The aim of the study was the comparison of conventional sintering versus additive manufacturing techniques for β-TCP bioceramics, focusing on mechanical properties and biocompatibility. A "critical" bone defect requires surgical intervention beyond simple stabilization. Autologous bone grafting is the gold standard treatment for such defects but it has its limitations. Alloplastic bone grafting using synthetic materials is becoming increasingly popular. The use of bone graft substitutes has increased significantly and current research was focused on optimizing these substitutes, whereas this study compares two existing manufacturing techniques and the thereby produced β-TCP implants. The 3D-printed β-TCP hybrid structure implant was fabricated using two components, a column structure and a freeze-foam, which were sintered together. The conventionally manufactured ceramics were made by pouring. Both scaffolds were characterized according to porosity, mechanical properties and biocompatibility. The hybrid structure had a total porosity of 74.4 ± 0.5%. Microporous β-TCP implants had a porosity of 43.5 ± 2.4%, while macroporous β-TCP implants had a porosity of 61.81%. Mechanical testing revealed that the hybrid structure had a compressive strength of 10.4 ± 6 MPa, significantly lower than the microporous β-TCP implant’s with 32.9 ± 8.7 MPa. Biocompatibility evaluations showed a steady increase in cell proliferation over time for all β-TCP implants, with minimal cytotoxicity. This study provides valuable insight into the potential of additive manufacturing for β-TCP bioceramics in the treatment of bone defects.

Pericytes, as perivascular cells, are present in all vascularized organs and tissues, and they actively interact with endothelial cells in capillaries and microvessels. Their involvement includes functions like blood pressure regulation, tissue regeneration, and scarring. Studies have confirmed that pericytes play a crucial role in bone tissue regeneration through direct osteodifferentiation processes, paracrine actions, and vascularization. Recent pre-clinical and clinical experiments have shown that combining perivascular cells with osteogenic factors and tissue-engineered scaffolds can be therapeutically effective in restoring bone defects. This approach holds promise for addressing bone-related medical conditions. In this review, we have emphasized the characteristics of pericytes and their involvement in angiogenesis and osteogenesis. Furthermore, we have explored recent advancements in the use of pericytes in preclinical and clinical investigations, indicating their potential as a therapeutic resource in clinical applications.

Although researchers have proposed various indentation size effect (ISE) models, these models often involve different form and number of parameters that can make our wonder which is the best in existed ISE models. Three types of ISE test data, namely, normal ISE, reverse ISE and transition of normal to reverse ISE, are used to evaluate the sixteen ISE models. The comparatively study indicates that H-J, N-G-Fs, N-G-H, N-G-A and N-G-Qs models can accurately predict the normal ISE. The reason for this is that the friction stress that is not related to dislocation activities or the indentation size effect of plastic zone has been introduced into these models. Therefore, these two factors should be considered in future ISE models. The sixteen ISE models are originally proposed to describe the normal ISE of different materials. However, to our surprise, some of these models are able to capture the reverse ISE and the transition of normal to reverse ISE of different materials. The determination coefficients (DC) of the sixteen ISE models are also determined for different materials. For reverse ISE, the highest DC value for NiCSi, TC4 and PED Ni are given by the EXP, N-G-Fs and N-G-A models, respectively. For the transition of normal to reverse ISE, the N-G-YC, N-G-Fs, and N-G-H models produce the maximum DC for ZrO2, Cu and Y2O3-ZrO2, respectively. Moreover, the mean DC of the N-G-Fs model is the maximum among the sixteen ISE models, followed by the N-G-H model, but they cannot accurately predict the reverse ISE. Therefore, the N-G-Fs and N-G-H models should be further modified to accurately predict the reverse ISE.

In bone tissue engineering, ceramics have been the choice due to their excellent biological properties. But the paradigm changed with the discovery of bioactive glasses (BGs) in 1969 by Larry Hench and co-workers, due to their ability to bond to living tissues through the formation of an interfacial bone-like hydroxyapatite layer when the bioglass was put in contact with biological fluids in vivo. Among a number of tested compositions, the one exhibiting the highest bioactivity index is the well-known trademarked 45S5 Bioglass®. The topic received increasing attention particularly after 1985 when this material entered in the market of biomedical devices, inspiring many other investigations aiming at further exploring the in vitro and in vivo performances of this BG, or developing other related BG compositions. The research efforts gradually revealed a number of shortcomings of 45S5 Bioglass®, mostly derived from its high sodium content, initially intended to decrease the melting temperature and accelerating the degradation of the silicate network over time. But the extensive release of sodium from 45S5 Bioglass® in the biological fluids creates a high pH cytotoxic environment. Other serious drawbacks include a fast degradation rate, and a poor sintering ability, which hinders the reliable fabrication of porous scaffolds. Therefore, sol-gel was regarded as an attractive alternative to prepare alkali-free BG compositions. The process uses inorganic and/or organic precursors, which undergo hydrolysis and condensation at room-temperature, being less costly. When properly conducted, the sol-gel process might result in amorphous structures with all the components intimately mixed at the atomic scale. Moreover, developing new better performing materials for bone tissue engineering is a growing concern, as the ageing of the world’s population leads to lower bone density and osteoporosis. This work describes the sol-gel synthesis of a novel quaternary silicate-based BG with the composition 60 SiO2 – 34 CaO – 4 MgO – 2 P2O5 (mol%) was prepared using acidified distilled water as single solvent. By controlling the kinetics of the hydrolysis and condensation steps, an amorphous glass structure could be obtained. The results of XRD of samples calcined within the temperature range from 600-900 ºC demonstrated that amorphous nature was maintained until 800 ºC, followed by partial crystallization at 900 ºC. The specific surface area, an important factor in osteoconduction, was also evaluated over different temperatures, ranging from 160.6 ± 0.8 m2/g at 600 ºC down to 2.2 ± 0.1 m2/g at 900 ºC, being accompanied consistent changes in average pore size and agreeing pore size distribution. The immersion of the BG particles in simulated body fluid (SBF) led to the formation of an extensive apatite layer on its surface. These overall results indicate the proposed material is very promising for biomedical applications in bone regeneration and tissue engineering.

Bone tissue engineering has developed significantly in recent years as the increasing demand for bone substitutes due to trauma, cancer, arthritis, and infections. The scaffolds for bone regeneration need to be mechanically stable and have a 3D architecture with interconnected pores. With the advances in additive manufacturing technology, these requirements can be fulfilled by 3D printing scaffolds with controlled geometry and porosity using a low-cost multistep process. The scaffolds, however, must also be bioactive to promote the environment for the cells to regenerate into bone tissue. To determine if a low-cost 3D printing method for bespoke SiOC(N) porous structures can regenerate bone these structures were tested for osteointegration potential by using human mesenchymal stem cells (hMSCs). This includes checking the general biocompatibilities under the osteogenic differentiation environment (cell proliferation and metabolism). Moreover, cell morphology was observed by confocal microscopy and gene expressions on typical osteogenic markers at different stages for bone formation were determined by real-time PCR. The results of the study showed the pore size of the scaffolds had a significant impact on differentiation. A certain range of pore size could stimulate osteogenic differentiation, thus promoting bone regrowth and regeneration.

The loss or dysfunction of skeletal tissue often necessitates surgical intervention, particularly in cases involving trauma, tumors, or abnormal development leading to critical-sized defects. Despite autografts being considered the gold standard for bone grafts, their limitations and complications prompt the exploration of alternative approaches for bone repair and regeneration. Current advancements in bone tissue engineering have led to innovative strategies aiming to regenerate injured bone structures, providing viable alternatives to traditional autografts or allografts. Among these strategies, Hydrogel Microparticles (HMPs) have emerged as promising scaffolds due to their notable characteristics, including high porosity and mechanical tunability. HMPs play an important role in facilitating vasculature formation, mineral deposition, and overall bone tissue regeneration. HMPs, fabricated through various techniques, exhibit versatility in functions such as drug and cell delivery, structural scaffolding, and bioinks for 3D printing. In addition, these microgels can be injected for minimally invasive delivery and can display modular properties with different designs and configurations. This review exclusively focuses on the advancements in HMPs for bone regeneration, delving into synthesis and functionalization techniques while highlighting their diverse applications documented in the literature. Our aim is to shed light on the unique benefits and potential of HMPs in the intricate field of engineering bone tissue.

The regeneration of bone tissue is a main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, while it should be resorbed even in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated and it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also on osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between the formation of new bone tissue and material degradation has not been found until now. The addition of different substances such as collagen or growth factors and also of different cell types have already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are differently used as basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designated for bone regeneration with the aim to give an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

Segmental bone defects caused by trauma, infection, tumor resection or osteoporotic fractures present significant surgical treatment challenges. Host bone autograft is considered the gold standard to restore function but comes with the cost of harvest site comorbidity. Allograft bone is a secondary option but has its own limitations in incorporation with host bone as well as cost. Therefore, developing new bone tissue engineering strategies to treat bone defects is critically needed. In the past three decades, the use of stem cells delivered with different scaffolds or growth factors for bone tissue engineering has made tremendous progress. Many varieties of stem cells have been isolated from different tissues for use in bone tissue engineering. This review summarizes the progress in using different postnatal stem cells including bone marrow mesenchymal stem cells, muscle-derived stem cells, adipose-derived stem cells, dental pulp stem cells/periodontal ligament stem cells, periosteum stem cells, umbilical cord-derived stem cells, peripheral blood stem cells and urine-derived stem cells for bone tissue engineering and repair. This review also summarizes the progress using exosomes or extracellular vesicles delivered with various scaffolds for bone repair. The advantages and disadvantages of each type of stem cell are also discussed and explained in detail. It is hopeful in the future that these preclinical results will translate into new therapies for bone defect repair.

Mass transfer restrictions of scaffolds are currently hindering the development of three-dimensional (3D), clinically viable, and tissue engineered constructs. For this situation, a 3D poly(lactide-co-glycolide)/hydroxyapatite porous scaffold, which was much favorable for transfer of nutrients to and waste products from the cells in the pores, was developed in this study. The 3D scaffold had an innovative structure, including macropores with diameters of 300−450 μm for cell ingrowth and microchannels with diameters of 2−4 μm for nutrition and waste exchange. The mechanical strength in wet state was strong enough to offer the structural support. The typical structure was more beneficial for the attachment, proliferation, and differentiation of rabbit bone marrow mesenchymal stem cells (rBMSCs). The alkaline phosphatase (ALP) activity and calcium (Ca) deposition were evaluated on the differentiation of rBMSCs, and the results indicated that the microchannel structure was very favorable for differentiating rBMSCs into maturing osteoblasts. For repairing rabbit radius defects in vivo, there was rapid healing in the defects treated with the 3D porous scaffold with microchannels, where the bridging by a large bony callus was observed at 12 weeks post-surgery. Based on the results, the 3D porous scaffold with microchannels was a promising candidate for bone defect repair.

The retina is a complex and fragile photosensitive part of the central nervous system which is prone to degenerative diseases leading to permanent vision loss. No proven treatment strategies exist to treat or reverse the degenerative conditions. Recent investigations demonstrate that cell transplantation therapies to replace the dysfunctional retinal pigment epithelial (RPE) cells and or the degenerating photoreceptors (PRs) are viable options to restore vision. Pluripotent stem cells, retinal progenitor cells and somatic stem cells are the main cell sources used for cell transplantation therapies. The success of retinal transplantation based on cell suspension injection is hindered by limited cell survival and lack of cellular integration. Recent advances in material science helped to develop strategies to grow cells as intact monolayers or as sheets on biomaterial scaffolds for transplantation into the eyes. Such implants are found to be more promising than the bolus injection approach. Tissue engineering techniques are specifically designed to construct biodegradable or non-degradable polymer scaffolds to grow cells as a monolayer and construct implantable grafts. The engineered cell construct along with the extracellular matrix formed, can hold the cells in place to enable easy survival, better integration and improved visual function. This article reviews the advances in the use of scaffolds for transplantation studies in animal models and its application in current clinical trials.

Periodontitis is a chronic inflammatory disease which results in the destruction of the tooth’ s supporting tissues and the alveolar bone resorption. The complement becomes a major link between infection and inflammatory pathology including periodontitis. Gingipians as important virulence factors of P. gingivalis have the activity of C5 convertase, could cleave C5 into fully functional C5a to activate C5aR. The above process could be blocked by the C5aR antagonist (PMX-53) to suppress local periodontal inflammation, and then achieves the purpose of treatment of periodontitis. Nanoparticles incorporated within gelatin are promising carrier system for drug delivery in recent years. This study aimed to investigate whether gelatin nanoparticles loaded with PMX-53 prevents alveolar bone resorption in miniature swines model of periodontitis. Four miniature swines were placed ligatures around the maxillary and mandibular fourth premolar and first molar on both sides for seven weeks to induce periodontitis. Then, animals were assigned randomly to four groups: minocycline-treated group, gelatin with PMX53-treated group, gelatin-treated group and a sham control group. They were treated with 1ml related drugs respectively, into gingival sulcusl for 4 times at one-week intervals. We showed that local treatments with gelatin nanoparticles loaded with PMX-53 could inhibit alveolar bone loss of periodontitis. Our study revealed that gelatin nanoparticles loaded with PMX-53 prevented alveolar bone resorption miniature swines model of periodontitis. In addition, provided proof-of-concept for local targeting of gelatin nanoparticles loaded with PMX-53 as a powerful candidate for the treatment of periodontitis.

Octacalcium phosphate (OCP) is a precursor of biological apatite crystals that has attracted attention as a possible bone substitute. On the other hand, few studies have examined this material at the experimental level due to the limitations of OCP mass production. Recently, mass production technology of OCP was developed, and the launch of OCP bone substitutes is occurring. In this study, the bone regeneration capacity of OCP products was compared with two of the most clinically used materials: heat-treated bovine bone (BHA) and sintered biphasic calcium phosphate (BCP). Twelve rabbits were used, and defects in each tibia were filled with OCP, BHA, BCP, and left unfilled as control (CON). The tibias were harvested at 4 and 12 weeks, and 15 μm slides were prepared using the diamond grinding method after being embedded in resin. Histological and histomorphometric analyses were performed to evaluate the bone regeneration ability and mechanism. The OCP showed significantly higher resorption and new bone formation in both periods analysed (p<0.05). Overall, OCP bone substitutes can enhance bone regeneration significantly by activating osteoblasts and a rapid phase transition of OCP crystals to biological apatite crystals (mineralisation), as well as providing additional space for new bone formation by rapid resorption.

Scaffold guided breast tissue regeneration (SGBTR) can both transform reconstructive and cosmetic breast surgery. Implant-based surgery is the most common method. However, there are inherent limitations as there is replacement of tissue rather than regeneration. Regenerating autologous soft tissue has the potential to provide a more like-for-like reconstruction with minimal morbidity. Our SGBTR approach regenerates soft tissue by implanting additively manufactured bioresorbable scaffolds filled with autologous fat graft. A pre-clinical large animal study was conducted implanting 100 ml breast scaffolds (n=55) made from medical-grade polycaprolactone in 11 minipigs for 12 months. Various treatment groups were investigated where immediate or delayed autologous fat graft, as well as platelet rich plasma were added to scaffolds. Computed Tomography and Magnetic Resonance Imaging was performed on explanted scaffolds to determine volume and distribution of regenerated tissue. Histological analysis was performed to confirm tissue type. At 12 months we were able to regenerate and sustain a mean soft tissue volume of 60.9 4.5 ml (95% CI) across all treatment groups. There was no evidence of capsule formation. There were no immediate or long-term post-operative complications. In conclusion, we were able to regenerate clinically relevant soft tissue volumes utilizing SGBTR in a pre-clinical large animal model.

The healing of osteochondral defects (OCD) resulting from injury, osteochondritis, or osteoarthritis in middle- and old-age individuals, bearing lesions in the cartilage and bone, pain, and loss of joint function, presents challenges to the clinical practitioners because of non-regenerative cartilage and the limitations of current therapies. Bioactive peptide-based osteochondral (OC) tissue regeneration is becoming more popular because it does not have the immunogenicity, misfolding, or denaturation problems associated with original proteins. Periodically, reviews are published on the regeneration of bone and cartilage; however, none of them address the simultaneous healing of these tissues in the complicated heterogeneous environment of the OC interface. As regulators of cell adhesion, proliferation, differentiation, angiogenesis, immunomodulation, and antibacterial activity, potential therapeutic strategies for OC defects utilizing bone and cartilage-specific peptides should be examined and investigated. Therefore, the main goal of this review is to study how they contribute to the healing of OC defects, either alone or in conjunction with other peptides and biomaterials.

The increase in the rate and prevalence of diseases associated with the localized and general loss of bone mass calls for an investigation into therapeutic alternatives that largely involve the de-velopment of new biomaterials and cell therapy, converting tissue bioengineering into a prom-ising option. An experimental model of a critical mandibular lesion in rats has been used to study bone re-generation by treating the ostectomy with the biomaterials Evolution® and Gen-Os® (OsteoBiol®, Italy) combined, or not, with dental pulp stem cells (DP-MSC). The results obtained through the Micro-CT and histological study reveal the almost complete re-covery of the lesion in the group with DP-MSC. These results are supported by increases in endoglin, TGF-β, protocollagen I, parathormone, and calcitonin, generating an environment of bone generation and development when combining Evolution® and Gen-Os® (OsteoBiol®, Italy) with DP-MSC. These promising results confirm the transcendental role of DP-MSC in combina-tion with osteogenic biomaterials for bone regeneration, and warrant further studies, including its assessment in clinical trials.

The three-dimensional printing of scaffolds is an interesting alternative to the traditional techniques of periodontal regeneration. This technique uses computer assisted design and manufacturing after CT scan. After 3D modelling, individualized scaffolds are printed by extrusion, selective laser sintering, stereolithography, or powder bed inkjet printing. These scaffolds can be made of one or several materials such as natural polymers, synthetic polymers, or bioceramics. They can be monophasic or multiphasic and tend to recreate the architectural structure of the periodontal tissue. In order to enhance the bioactivity and have a higher regeneration, the scaffolds can be embedded with stem cells and/or growth factors. This new technique could enhance a complete periodontal regeneration. This review summarizes the application of 3D printed scaffolds in periodontal regeneration. The process, the materials and designs, the key advantages and prospects of 3D bioprinting are highlighted, providing new ideas for tissue regeneration.

The effective treatment for chronic wounds constitute one of the most common worldwide health care problem due to the presence of high levels of proteases, free radicals and exudates in the wound, which constantly activate the inflammatory system avoiding the tissue regeneration. In this study, we describe a multifunctional bioactive and resorbable membrane with in-built antioxidant agent for the continuous quenching of free radicals as well as to control inflammatory response helping to promote the wound healing process. To reach that goal synthesized statistical copolymers of N-vinylcaprolactam (V) and 2-hydroxyethyl methacrylate (H) have been conjugated with catechol bearing hydrocaffeic acid (HCA) molecules. The natural polyphenol (catechol) is the key molecule responsible for the mechanism of adhesion of mussels, and provides the functionalized polymer conjugate a continuous antioxidant response, antiinflammatory effect, UV screen and bioadhesion in the moist environment of the human body, all of them key features in the wound healing process. Therefore, these novel mussel-inspired materials have an enormous potential of application and can act very positively, favoring and promoting the healing effect in chronic wounds.

Abstract: This article provides a brief review of the ontogeny of chondrocytes and the pathophysiology of osteoarthritis (OA), and details how physical exercise improves the health of osteoarthritic joints and enhances the potential of mesenchymal stem cells for successful transplantation therapy. In response to exercise chondrocytes increase their production of glycosaminoglycans, bone morphogenic proteins and antiinflammatory cytokines and decrease their production of proinflammatory cytokines and matrix degrading metalloproteinases. These changes are associated with improvements in cartilage organization and reductions in cartilage degeneration. Studies in humans indicate that exercise increases peripheral blood recruitment of bone marrow-derived mesenchymal stem cells (BM-MSC) and upregulates BM-MSC expression of osteogenic and chondrogenic genes, osteogenic micro-RNAs, and osteogenic growth factors. Rodent experiments are uniform in demonstrating that exercise enhances the osteogenic potential of BM-MSC while diminishing their adipogenic potential, and that exercise done after stem cell implantation may benefit stem cell transplant viability. Physical exercise also exerts a beneficial effect on the skeletal system by decreasing immune cell production of osteoclastogenic cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and interferon (INF)-γ while increasing their production anti-osteoclastogenic cytokines IL-10 and transforming growth factor (TGF)-β. In conclusion, physical exercise done both by stem cell donors and recipients may improve the outcome of mesenchymal stem cell transplantation.

Objectives: The promising specific growth regulators are employed tissue culture of the bamboo species. The specific natural hardening mixture supports the acclimatization and adaptation of the protected cultivation. The bamboo species contribute to the carbon sequestration and stabilization of the environment. Findings: The growth regulator 2, 4-D encourages callus induction and growth regulators NAA + TDZ, BAP + Kinetin + Gelrite, BAP + Kinetin + Coconut water + myo-inositol, NAA and TDZ impose plant regeneration in the Bambusa species. The growth regulator of 2,4-D, 2,4-D + Kinetin, 2,4-D + BA, 2,4-D + BAP and 2,4-D + NAA + BAP produces callus induction in the Dendrocalamus species. The growth regulator of TDZ, BA and IBA + Coumarin + Putrescine, BAP + GA3, NAA + Kinetin, BA + IBA, BA + Kinetin + NAA, NAA + Kinetin, Kinetin + IAA has facilitated shoot regeneration in the Dendrocalamus species with the specific period. The growth regulator of BA and TDZ; BAP + TDZ, IBA + Coumarin + Putrescine, BAP + GA3, NAA + Kinetin, BA + IBA, BA + Kinetin + NAA, NAA + Kinetin, Kinetin + IAA develops root regeneration with unambiguous time in the Dendrocalamus species. The growth regulator of BAP and Kinetin + BAP imposes shoot regeneration and IBA and IBA + Coumarin + sucrose conducts root regeneration in the edible bamboo. The natural hardening materials of cocopeat, vermicompost, perlite, cow dung, FYM, compost, soil & garden soil and humus soil, perlite, and FYM recommend in the acclimatization and adaptation of the Bambusa species and Dendrocalamus species respectively. Novelty: The standard growth regulators and hardening mixtures impose tissue culture, acclimatization and adaptation in the bamboo species. The bamboo species involves in managing carbon sequestration, biogeochemical cycle and the environment.

Osteoporosis is a bone condition where bones become weaker, leading to fractures, especially in older adults and postmenopausal women. Bioceramics for bone regeneration have indeed emerged as a promising solution for conditions like osteoporosis. Choosing the right bioceramic depends on how quickly it dissolves, how strong it is, and whether the body will react to it. Studies show that bioceramics can help bones grow back by activating (bone morphogenetic protein) BMP, (mitogen-activated protein kinase) MAPK, and Wingless/integrated (Wnt)/β-catenin pathways in the body when combined with stem cells, drugs, and supports. However, bioceramics have some problems like not being flexible enough and being prone to breaking, as well as difficulties in growing stem cells and finding the right supports for different bone types. While there has been progress in improving bioceramics for bone healing, we need to keep looking for new ideas from other areas of medicine to keep improving them. This review aims to add to the expanding field of scientific research by offering a detailed look at how bioceramics and growth factors contribute to bone regeneration. Ultimately, this knowledge will help in creating new types of bioceramics that can improve bone regrowth, providing new treatment options for people with bone diseases.

Nanomedicine has allowed for emerging advances in imaging, diagnostics and therapeutics. Regenerative Medicine has taken advantage of a number of nanomaterials for reparation of diseased or damaged tissues in the nervous system involved in memory, cognition and movement. Electrical, thermal, mechanical and biocompatibility aspects of carbon-based nanomaterials (nanotubes, graphene, fullerenes and their derivatives) make them suitable candidates to drive nerve tissue repair and stimulation. This review article focuses on recent advances on the use of carbon nanotube (CNT)-based technologies on nerve tissue engineering; outlining how neurons interact with the nanomaterials interface for promoting neuronal differentiation, growth and network reconstruction for their possible use in therapies of neurodegenerative pathologies and spinal cord injuries.

Recent research efforts in bone tissue engineering have been primarily directed towards manufacture-viable synthesis of biomaterials that can significantly enhance the biocompatibilities and osteogenic capabilities on the new biomaterials. This paper presents a straightforward, cost-effective, optimized, and well-controlled hydrothermal synthesis of Nb-doped potassium titanate nanofibers in high-purity. Characterization data revealed that the Nb-doping potassium titanate maintained the crystal structure, showing great promise for applications in bone tissue engineering.

Recently, nanotechnologies have become increasingly prominent in the field of bone tissue engineering (BTE), offering substantial potential to advance the field forward. These advancements manifest in two primary ways: the localized application of nanoengineered materials to enhance bone regeneration and their use as nano-vehicles for delivering bioactive compounds. Despite significant progress in the development of bone substitutes over the past few decades, it is worth noting that the quest to identify the optimal biomaterial for bone regeneration remains a subject of intense debate. Ever since its initial discovery, poly(lactic-co-glycolic acid) (PLGA) has found widespread use in BTE due to its favorable biocompatibility and customizable biodegradability. This review provides an overview of contemporary advancements in the development of bone regeneration materials using PLGA polymer. The review covers some of PLGA properties with a special focus on modifications of these properties towards bone regeneration. Furthermore, we delve into the techniques for synthesizing PLGA nanoparticles (NPs), the diverse forms in which these NPs can be fabricated, and the bioactive molecules that exhibit therapeutic potential for promoting bone regeneration. Additionally, we addressed some of the current concerns regarding the safety of PLGA NPs, and PLGA-based products available in the market. Finally, we briefly discussed some of the current challenges and proposed some strategies to functionally enhance the fabrication of PLGA NPs towards BTE. We envisage that the utilization of PLGA NP holds significant potential as a potent tool in advancing therapies for intractable bone diseases.

Mandibular critical size defect (CSD) due to pathological conditions, trauma, and congenital disease can not heal spontaneously and predominantly filled with fibrous tissue. Therefore, a Guided Bone Regeneration (GBR) combined with bone grafting can be performed. The researchers considered using Demineralized Dentin Material Membrane (DDMM) from bovine dentine as an alternative GBR. This study aimed to determine the amount of fibroblast and collagen density after DDMM and bone graft implantation on CSD. Thirty-six Rattus norvegicus rats were used as samples. Mandibular bone defect 5x5 mm was made, then filled with bone graft and covered with Bovine Pericardium Collagen Membrane (BPCM) in the control group and DDMM in the treatment group. Six samples were sacrificed on 7, 14, and 21 days post-surgical for histology examination. There were no significant differences in the amount of fibroblast and collagen density (p-value > 0,05). The amount of fibroblast is lower and the collagen density is higher in treatment group. DDMM has microporosity to prevent connective tissue ingrowth and dentine tubules to allow growth factors release. DDMM and bone graft implantation can reduce the amount of fibroblasts and increase collagen density of CSD which potentially being used as a CSD alternative treatment for bone regeneration.

Three-dimensional (3D) printing techniques have received considerable focus in the area of bone engineering due to its precise control in the fabrication of complex structures with customizable shapes, internal and external architectures, mechanical strength, and bioactivity. In this study, we design a new composition biomaterial consisting of polylactic acid (PLA), and halloysite nanotubes (HNTs) loaded with zinc nanoparticles (PLA+H+Zn). The hydrophobic surface of the 3D printed scaffold was coated with two layers of fetal bovine serum (FBS) on the sides and one layer of NaOH in the middle. Additionally, a layer of gentamicin was coated on the outermost layer against bacterial infection. Scaffolds were cultured in standard cell culture medium without the addition of osteogenic medium. This surface modification strategy improved material hydrophilicity and enhanced cell adhesion. Pre-osteoblasts cultured on these scaffolds differentiated into osteoblasts and proceeded to produce a type I collagen matrix and subsequent calcium deposition. 3D printed scaffolds formed from this composition possessed high mechanical strength and showed an osteoinductive potential. Furthermore, the external coating of antibiotics not only preserved the previous osteogenic properties of the 3D scaffold but also significantly reduced bacterial growth. Our surface modification model enabled the fabrication of a material surface that was hydrophilic and antibacterial, simultaneously, with an osteogenic property. The designed PLA+H+Zn may be a viable candidate for the fabrication of customized bone implants.

Teeth include mesenchymal stem cells (MSCs), which are multipotent cells that promote tooth growth and repair. Dental tissues, specifically the dental pulp and the dental bud, constitute a relevant source of multipotent stem cells, known as dental-derived stem cells (d-DSCs): dental pulp stem cells (DPSCs) and dental bud stem cells (DBSCs). Cell treatment with bone-associated factors and stimulation with small molecule compounds are, among the available methods, the ones who show excellent advantages promoting stem cell differentiation and osteogenesis. Recently, attention has been paid to studies on natural and non-natural compounds. Many fruits, vegetables and some drugs contain molecules that can enhance MSC osteogenic differentiation and therefore bone formation. The purpose of this review is to examine research work over the past 7 years that has investigated two different types of MSCs from dental tissues that are attractive targets for bone tissue engineering: DPSCs and DBSCs. We focused on articles hypothesizing the identification and study of compounds that induce proliferation and osteogenic differentiation of the two d-DSC populations, representing an interesting issue for regenerative medicine. The reconstruction of bone defects in fact is still a challenge for personalized medicine.

Materials based on Mg2+-containing phosphates are gaining great relevance in the field of bone tissue repair via regenerative medicine methods. Magnesium ions, together with condensed phosphate ions, play a significant role in the process of bone remodeling, affecting the early stage of bone regeneration through active participation in the process of osteosynthesis. Here we pro-vide a comprehensive overview of the usage of biomaterials based on magnesium phosphate and magnesium calcium phosphate in bone reconstruction. The role of magnesium ions in angiogene-sis, an important process associated with osteogenesis, is considered. Finally, the biological properties of magnesium phosphates for bone regeneration are summarized. They show promis-ing results in terms of use as bone replacement material.

Objective: Regeneration of bone defects remains a challenge for maxillofacial and reparative surgeons. The purpose of this histological study was to assess the osteogenic potential of octacalcium phosphate (OCP) and bone matrix gelatin (BMG) alone and in combination in artificially created mandibular bone defects in rats. The quality of the newly formed bone was also evaluated. Methods: Thirty-six male Sprague Dawley rats (6-8 weeks old with 120-150 g weight) were randomly divided into four groups. Defects (3 mm in diameter and 2 mm in depth) were created in the mandible of rats and filled with 6 mg of OCP, BMG or a combination of both (1/4 ratio), respectively. Defects were left unfilled in the control group. To assess osteoinduction and bone regeneration and determine the quality of the newly formed bone, tissue specimens were harvested at seven, 14, and 21 days post-implantation. The specimens were processed, stained with hematoxylin and eosin (H&E) and histologically analyzed under light microscopy. Results: In the experimental groups, new bone formation was initiated at the margins of defects from seventh day after implantation. At the end of the study period, the amount of the newly formed bone increased and the bone was relatively mature. Osteoinduction and new bone formation were greater in OCP/BMG group. In the control group, slight amount of new bone had been formed at the defect margins (next to host bone) on day 21. Conclusion: Combination of OCP/BMG may serve as an optimal biomaterial for treatment of mandibular bone defects.

Synthetic bone made of calcium phosphate is widely used for the clinical treatment of bone defects caused by trauma and bone tumors. Although synthetic bone is easy to use, its effects are only partial depending on the size and location of the bone defect, and there are many treatment options other than the use of synthetic bone. Various biodegradable polymers that are being considered for use as scaffolds for regenerative medicine are also being considered for use as synthetic bones; however, commercial synthetic bone products with performance comparable to that of calcium phosphate bioceramics have not yet been clinically applied. This review introduces the practice of bone regeneration therapy with synthetic bone and recent research on bone regeneration therapy with biodegradable polymers.

Globally, cancer is an important health problem worldwide, and has become one modern medicine’s most serious problems to prevent, diagnose, and treat. Many types of cancers still have non-negligible mortality rates, and new treatments need to be developed for them. This study aimed to elucidate cancer mechanisms and facilitate cancer treatment and prevention. The ideal temperature for cancer growth is 35°C; however, conditions were not consistent with chromosomal instability, loss of alleles of tumor-suppressor genes, abnormal DNA methylation, and collagen phagocytosis, which are known causes of cancer. In addition, when cancer develops, white blood cells attack the cancer tissue and remove it; however, as the decrease in body temperature drops, leads to a reduction in the immune potential of the white blood cells. Based on previous papers, this study focused on aimed to determine the effects of the low-temperature environment of 35°C, the temperature at which cancer is most likely to proliferate, and changes in adenosine triphosphate (ATP) levels. The study revealed that Therefore, the causes of cancer is caused by include chromosome fusion that occurs occurring due to the impaired DNA topoisomerase IIα proliferation and primary cilia rotation due to resulting from decreased intercellular adhesion.

Polyetheretherketone (PEEK) in the last few years emerged as an exceedingly promising material for craniofacial defect, due to its biocompatibility and mechanical properties. However, its utilization remains controversial due to its inertness and low osteoinductivity. This study aimed to investigate the postoperative outcomes of patients undergoing maxillo-facial and neurosurgical procedures with PEEK implants. The focus is on evaluating bone regrowth on the surface and edges of the implant, periosteal reactions, and implant positioning. A retrospective analysis of 12 maxillo-facial surgery patients and 10 neurosurgery patients who received PEEK implants was conducted. CT scans performed at least one-year post-operation, were examined for bone regrowth, periosteal reactions, and implant positioning. In maxillo-facial cases, the analysis included mandibular angle and fronto-orbital reconstruction, while neurosurgical cases involved cranioplasty. In maxillofacial surgery, 11 out of 12 patients showed radiological evidence of bone regrowth around PEEK implants, with favorable outcomes observed in craniofacial reconstruction. In neurosurgery, 9 out of 10 patients exhibited minimal or none bone regrowth, while one case demonstrated notable bone regeneration beneath the PEEK implant interface. The study highlights the importance of implant design and patient-specific factors in achieving successful outcomes, providing valuable insights for future implant-based procedures.

Mesenchymal stem cells (MSCs) hold immense therapeutic potential due to their regenerative and immunomodulatory properties. However, to utilize this potential, it is crucial to optimize their in vitro cultivation conditions. Three-dimensional (3D) culture methods using cell-laden hydrogels aim to mimic the physiological microenvironment in vitro, thus preserving MSC biological functionalities. Cellulosic hydrogels are particularly promising due to their biocompatibility, sustainability, and tunability in terms of chemical, morphological, and mechanical properties. This study investigated the impact of (1) two physical crosslinking scenarios for hydrogels derived from anionic cellulose nanofibers (CNF) used to encapsulate adipose-derived MSCs (adMSCs) and (2) physiological culture conditions on the in vitro proliferation, differentiation, and extracellular vesicle (EV) production of these adMSCs. Our results revealed that additional Ca2+-mediated crosslinking, intended to complement self-assembly and gelation of aqueous to-CNF in the adMSC cultivation medium, adversely affected both the mechanical properties of the hydrogel spheres and the growth of the encapsulated cells. However, cultivation under dynamic and hypoxic conditions significantly improved the proliferation and differentiation of the encapsulated adMSCs. Furthermore, we demonstrated that adMSCs in CNF hydrogel spheres exhibited potential for scalable EV production with potent immunosuppressive capacities in a bioreactor system. These findings underscore the importance of physiological culture conditions and the suitability of cellulosic materials for enhancing the therapeutic potential of MSCs. Overall, our study provides valuable insights for optimizing the in vitro cultivation of MSCs for various applications, including tissue engineering, drug testing, and EV-based therapies.

Dental pulp tissue engineering (TE) quests to regenerate dentin/pulp complex by combining a suitable supporting matrix, stem cells, and biochemical stimuli. Such procedures foresee a matrix that can be easily introduced into the root canal system (RCS) and tightly adhere to dentin walls to assure the dentin surface's proper colonization with progenitor cells capable of restoring the dentin/pulp complex. Herein was investigated an injectable self-setting hyaluronic acid-based (HA) hydrogel system, formed by aldehyde-modified (a-HA) with hydrazide-modified (ADH), enriched with platelet lysate (PL), for endodontic regeneration. The hydrogels' working (wT) and setting (sT) times, the adhesion to the dentine walls, the hydrogel's microstructure, and the delivery of human Dental Pulp Cells (DPCs) were studied in vitro. Hydrogels incorporating PL showed a suitable wT and sT and a porous microstructure. The tensile tests showed that the breaking point occurs after 4.13 mm deformation. While in the indentation test after 1.3 mm deformation. Both breaking points occur in the hydrogel extension. The HA/PL hydrogels exhibited supportive properties and promoted cell migration toward dentin surfaces in vitro. Overall, these results support using PL-laden HA injectable hydrogels (HA/PL) as a biomaterial for DPCs encapsulation, thereby displaying great clinical potential towards endodontic regenerative therapies.

Selected glasses with 10 Na₂O + (90-x) P₂O₅ + x BCD where bypass cement dust (BCD) x value =10, 20, 30 in mol% were synthesized by recognizable melting annealing technique. Cooperative characterization of the prepared glasses were carried out through FTIR and SEM analysis before and after immersed in simulated body fluid (SBF) solution for 13 and 23 days at 37 ^oC. After immersion in SBF, apatite layer is produced on the glass surface after 13 day and increase after 23 day, showing good bioactivity after immersion in the SBF especially for bioglass sample with 30% BCD. A porous hydroxy apatite layer produced on the surface of SBF-glass composite and this layer became denser after more soaking time, periods were extended from 13 to 23 days. Atomic absorption spectroscopy explained the early period of soaking that cause release of both Si and Ca ions through the glass beside decreasing of phosphrous ions. Bioglass (BCD-30) is studied as shielding for gamma, protons and alphas by using Phy-X software, SRIM Monte Carlo simulation code and its subroutine TRIM. The gamma shielding parameters, mass stopping power (MSP), range for both proton (H- ions) and alpha (He- ions) in bioglass- BCD-30 and human bone tissue have estimated. Also, comparison between them is calculated in predicting the radiation damage and atomic displacements per atom (dpa).

Autologous platelet-rich plasma (PRP) preparations are prepared at point of care. Centrifugation cellular density separation sequesters a fresh unit of blood into three main fractions: a platelet-poor plasma (PPP) fraction, a stratum rich in platelets (platelet concentrate) and, bioformulation dependent, also leukocyte and erythrocyte fractions. The employment of autologous platelet concentrates facilitates the biological potential to accelerate and support in numerous cellular activities that can lead to tissue repair, tissue regeneration, wound healing, and ultimately functional structural repair. Normally, after PRP preparation the PPP fraction is discarded. One of the less well known, but equally important features of PPP is that particular growth factors (GFs) are not abundantly present in PRP, as they reside outside the platelet alpha granules. Precisely, insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) are mainly present in the PPP fraction. In addition to their roles as angiogenesis activators, these plasma-based GFs are also known to inhibit inflammation, fibrosis, and they promote keratinocyte migration and support in tissue repair and wound healing. Additionally, PPP is known for the presence of exosomes and other macrovesicles, exerting cell-cell communication and cell signaling. Newly developed ultrafiltration technologies incorporate PPP processing methods by eliminating in a fast and efficient manner plasma water, cytokines, molecules, and plasma proteins with a molecular mass (weight) less than the pore size of the fibers. Consequently, a viable and viscous protein concentrate of functional, total proteins, like fibrinogen, albumin, and alpha-2-macroglobulin is created. Consolidating a small volume of high platelet concentrate with a small volume of highly concentrated protein-rich PPP creates a protein rich platelet concentrate (PRPC) biological preparation. After the activation of proteins, mainly fibrinogen, the PRPC matrix retains and facilitates interactions between invading resident cells, like macrophages, fibroblast, and mesenchymal stem cells (MSCs), and the embedded concentrated PRP cells and molecules. The administered PRPC biologic will ultimately undergo fibrinolysis, leading to a sustained release of concentrated cells and molecules that have been retained in the PRPC matrix until the matrix is dissolved. We will discuss the unique biological and tissue reparative and regenerative properties of PRPC matrix.

A novel scaffold design has been created to enhance tissue engineering and regenerative medicine by optimizing the controlled, prolonged release of hepatocyte growth factor (HGF), a powerful chemoattractant for endogenous mesenchymal stem cells. We present a new stacked scaffold that is made up of three different fibrin gel layers, each of which has HGF integrated into the matrix. The design attempts to preserve HGF's regenerative properties for long periods of time, which is necessary for complex tissue regeneration. These multi-layered fibrin gels have been mechanically evaluated using rheometry, and their degradation behavior has been studied using D-Dimer ELISA. Understanding the kinetics of HGF release from this novel scaffold configuration is essential for understanding HGF's long-term sustained bioactivity. A range of cell-based tests were carried out to verify the functionality of HGF following extended incorporation. These tests included 2-photon microscopy using phalloidin staining to examine cellular morphology, SEM analysis for scaffold-cell interactions, and scratch and scatter assays to assess migration and motility. The analyses show that the novel stacking scaffold promotes vital cellular processes for tissue regeneration in addition to supporting HGF's bioactivity. This scaffold design was developed for in situ tissue engineering. Using the body as a bioreactor, the scaffold should recruit mesenchymal stem cells from their niche thus combining the regenerative abilities of HGF and MSCs to promote tissue remodeling and wound repair.

Bone/fracture healing is a complex process with different steps and four basic tissue layers being affected: cortical bone, periosteum, fascial tissue surrounding the fracture, and bone marrow. Stem cells and their derivatives, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells, skeletal stem cells, and multipotent stem cells, can function to artificially introduce highly regenerative cells into decrepit biological tissues and augment the healing process at the tissue level. Stem cells are molecularly and functionally indistinguishable from standard human tissues. The widespread appeal of stem cell therapy lies in its potential benefits as a therapeutic technology that, if harnessed, can be applied in clinical settings. This review aims to establish the molecular pathophysiology of bone healing, the current stem cell interventions that disrupt or augment the bone healing process, and finally, consider the future direction/therapeutic options related to stem cells and bone healing.

Background: Complex bone defects are challenging to treat. Autografting is the gold standard for regenerating bone defects, however limitations include donor site morbidity and increased surgical complexity. Advancements in 3D bioprinting (3DBP) offer a promising alternative for viable bone grafts. Methods: Design of Experiments (DoE) was used to design 12 hydrogel bioinks of various Gelatin meth-acrylate/hydroxyapatite (GelMA/HA) concentrations. These bioinks were assessed for pipettability and equilibrium modulus. An optimal bioink was designed using the DoE data to produce the greatest stiffness while still being pipettable. Two bioinks, the DoE designed maximal stiff-ness and the experimentally defined maximal stiffness vs. a literature based control were then printed using a 3D bioprinter and assessed for print fidelity. The resulting hydrogels were combined with human bone-marrow-derived mesenchymal stromal cells (hMSCs) and evaluated for cell viability. Results: DoE ANOVA analysis indicated that the augmented 3 level factorial design model used was a good fit (p < 0.0001). Using the model, DoE correctly predicted that a composite hydrogel consisting of 12.3% GelMA, 15.7% HA, and 2% Gelatin would produce the maximum equilibrium modulus while still being pipettable. The hydrogel with the most optimal print fidelity was 10% GelMA, 2% HA, and 5% Gelatin. There were no significant differences in cell viability within hydrogels from day 2 to day 7 (p > 0.05). There was however a significantly lower cell viability in the gel composed of 12.3% GelMA, 15.7% HA, and 2% gelatin compared to the other gels with lower HA concentration (p < 0.05), showing that higher HA or print pressure may be cytotoxic within hydrogels. Conclusions: Extrusion-based 3DBP offers significant advantages for bone-tissue implants due to its high customizability. This study demonstrates it is possible to create printable bone-like grafts from GelMA and HA with increased HA levels, favorable mechanical properties (145kPa) and >80% cell viability.

Purpose: to assess any differences on marginal bone loss between bone-level or tissue-level dental implants through a review of literature until September 2019. Materials and methods: MEDLINE, Embase and other database were searched by two independent authors. The search was limited to articles in English. Results: The search provided 1028 records and, after removing the duplicates through titles and abstracts screening, 45 full-text articles were assessed for eligibility. For qualitative analysis 20 articles were included, 17 articles of them for quantitative analysis. A total of 1161 patients (mean age 54,4 years) and 2933 implants were observed, 1427 (Tissue-level) and 1506 (Bone-level). The survival rate and the success rate were more than 90%, except for 2 studies with a success rate of 88% and 86.2%. No studies reported any differences between groups in term of success and survival rates. Three studies showed that BL-implants had statistically less marginal bone loss (P< 0.05). Only one study reported statistically less marginal bone loss in TL-implants (P< 0.05). In the most part of the studies, differences between implant types in marginal bone loss were not statistically significant. Conclusion: Despite to the peri-implant tissue around transmucosal implants has been reported to be inflammation-free because of the absence of bacterial infiltration in the micro-gap between the fixture and abutment, no clinical and radiological differences were highlighted between groups from the included studies after a variable period of follow-up ranged between 1 to 5 years.

Composite biomaterials that combine osteoconductive and osteoinductive properties are a promising approach for bone tissue engineering (BTE) since it allows osteogenesis stimulation while mimicking the extracellular matrix (ECM) morphology. In this context, the aim of the present research work was to produce polyvinylpyrrolidone (PVP) nanofibers containing mesoporous bioactive glass (MBG) 80S15 nanoparticles. These composite materials were produced by electrospinning technique. The design of experiments (DOE) was used to estimate the optimal electrospinning parameters to reduce average fiber diameter. The polymeric matrices were thermally crosslinked under different conditions, and the fiber’s morphology was studied using scanning electron microscopy (SEM). Evaluation of the mechanical properties of nanofibrous mats revealed a dependence on thermal crosslinking parameters and on the presence of MBG 80S15 particles inside the polymeric fibers. Degradation tests indicated that the presence of MBG led to a faster degradation of nanofibrous mats. On the other hand, MBG presence also leads to higher swelling capacity. The assessment of in vitro bioactivity in simulated body fluid (SBF) was performed in MBG pellets and PVP/MBG (1:1) composites to assess whether the bioactive properties of MBG 80S15 were kept when it was incorporated into PVP nanofibers. FTIR and XRD analysis along with SEM–EDS results indicated that a hydroxy-carbonate apatite (HCA) layer was formed on the surface of MBG pellets and nanofibrous webs after soaking in SBF over different time periods. In general, the materials revealed no cytotoxic effects on Saos-2 cell line. The overall results for the produced materials show the potential of the composites to be used in BTE.

Bone metabolism is a complex process which is influenced by the activity of bone cells (e.g., osteocytes, osteoblasts, osteoclasts), the effect of some specific biomarkers (e.g., parathyroid hormone, vitamin D, alkaline phosphatase, osteocalcin, osteopontin, osteoportegerin, osterix, RANKL, Runx2) and the characteristic signaling pathways (e.g., RANKL/RANK, Wnt/β, Notch, BMP, SMAD). Some phytochemical compounds such as flavonoids, tannins, polyphenols, anthocyanins, terpenoids, polysaccharides, alkaloids and others presented a beneficial and stimulating effect in the bone regeneration process due to pro-estrogenic activity, antioxidant and anti-inflammatory effects and modulation of bone signaling pathways. Lately, nanomedicine has emerged as an innovative concept for new treatments in bone related pathologies envisaged by incorporation of medicinal substances in nanometric systems for oral or local administration, as well as in nanostructured scaffolds with huge potential in bone tissue engineering.

Notwithstanding the advances achieved in the last decades in the field of synthetic bone substitutes, the development of biodegradable 3D scaffolds with ideal mechanical and biological properties remains an unattained challenge. In this work, a novel approach is explored to produce synthetic bone grafts mimicking the complex bone structure using additive manufacturing. For the first time, scaffolds were produced, using an extrusion technique, composed of a thermoplastic polymer, polycaprolactone (PCL), hydroxyapatite nanoparticles (HANp), and polyethylene glycol diacrylate (PEGDA). These scaffolds were further compared with two groups of scaffolds: one composed of PCL and another of PCL and HANp. After production, optimisation and characterisation of these scaffolds, an in vitro evaluation was performed using human dental pulp stem/stromal cells (hDPSCs). Through the findings it was possible to conclude that PEGDA scaffolds were successfully produced presenting networks of interconnected channels, presenting hydrophilic properties (15.15 4.06°), adequate mechanical performance (10.41MPa 0.934), and allowing a cell viability significantly superior to the other groups analysed. To conclude, findings in this study demonstrated that PCL, HANp and PEGDA scaffolds may have promising effects on bone regeneration and might open new insights for 3D tissue substitutes.

Physical activity is well-established as an important protective factor against degenerative conditions and a promoter of tissue growth and renewal. The discovery of FNDC5 as the precursor of irisin in 2012 sparked significant interest in its potential as a diagnostic biomarker and a therapeutic agent for various diseases. Clinical studies have examined the correlation between plasma irisin levels and pathological conditions using a range of assays, but the lack of reliable measurements for endogenous irisin has led to uncertainty about its prognostic/diagnostic potential as an exercise surrogate. Animal and tissue-engineering models have shown the protective effects of irisin treatment in reversing functional impairment and potentially permanent damage, but dosage ambiguities remain unresolved. This review provides a comprehensive examination of the clinical and basic studies of irisin in the context of degenerative conditions and explores its potential as a therapeutic approach in the physiological processes involved in tissue repair/regeneration.

Critical sized bone defects and articular cartilage injuries resulting from trauma, osteonecrosis or age-related degeneration are often nonhealing by the physiological repairing mechanisms, thus representing a clinic issue due to the relevant epidemiological incidence. Current treatment approaches consist of autologous or allogenic grafting, which are associated with painfulness, morbidity, risk of infections and rejection. Novel tissue-engineering approaches, aiming at the reconstruction of damaged tissues, have been proposed as alternative solutions to these conven-tional methods. These approaches are based on the combination of three fundamental compo-nents: autologous or allogenic cells, a scaffold and growth-stimulating signals, which are gener-ally referred to as the tissue engineering triad. Three-dimensional polymer networks are fre-quently used as scaffolds to allow cell proliferation and tissue regeneration. In this scenario, cryogels are giving promising results as cell scaffolds over other polymer networks, thanks to their peculiar properties. In particular, cryogels possess an interconnected porous structure and a typical sponge-like behaviour, which facilitate the cellular infiltration and ingrowth. Their properties can be appropriately adjusted to match the requirements of the specific tissue or or-gan that it is intended to regenerate. In this review it is reported the state of the art on the fabri-cation and employment of cryogels in supporting osteo or chondro-genic differentiation for the re-building of more organized tissues. Moreover, it will highlight current progress and future perspectives in the implementation of this technology in the clinical practice.

Exosomes, nanoscale extracellular vesicles, are a hot area of investigation in the biomedical field, as they have been shown to play a crucial role in the physiology of numerous tissues, including bone. This study explores the landscape of exosome-based bone regeneration research using infometric techniques. By relying on BERTopic, an advanced topic modeling algorithm, we analyzed a comprehensive corpus of scientific literature to identify key themes and trends in exosome research in the bone regeneration field. We then extracted significant concepts from the abstracts of the corpus and we used them to create knowledge graphs using GPT 3.5 turbo Large Language Model, to map the distribution of information within this domain. The resulting ide-oscape highlights the key ideas that aggregate most of the recent research in the area, from mesenchymal stem cell-derived exosomes to engineered exosome-integrated biomaterials. This exploration provides a holistic view of the field and uncovers its emerging trends, providing useful insight to guide future research directions.

Bone fractures are very common in the geriatric population and poses a great economic burden worldwide. While traditional methods for repairing bone defects have primarily been autografts, there are several drawbacks limiting its use. Bone graft substitutes have been used as alternative strategies to improve bone healing. However, there remains several impediments to achieving the desired healing outcomes. Injectable hydrogels have become attractive scaffold materials for bone regeneration given their high performance in filling irregularly sized bone defects, ability to encapsulate cells and bioactive molecules, and mimic the native ECM of bone. We investigated the use of an injectable chitosan-based hydrogel scaffold to promote differentiation of preosteoblasts in vitro. The hydrogels were characterized by evaluating cell homogeneity, cell viability, rheological and mechanical properties, and differentiation ability of preosteoblasts in hydrogel scaffolds. Cell-laden hydrogel scaffolds exhibited shear thinning behavior and the ability to maintain shape fidelity after injection. The CNC-CS hydrogels exhibited higher mechanical strength and significantly upregulated the osteogenic activity and differentiation of preosteoblasts as shown by ALP activity assays and histological analysis of hydrogel scaffolds. These results suggest that this injectable hydrogel is suitable for cell survival, can promote osteogenic differentiation of preosteoblasts, and structurally support new bone growth.

Tooth extraction is the most common procedure in dental practice. However, in the long term, it may cause alveolar ridge atrophy. This systematic review aimed to evaluate the role of platelet-rich fibrin (PRF) in post-exodontic alveolar ridge preservation in terms of its effectiveness in the regeneration of bone tissue as assessed by imaging and its efficacy compared to physiological bone healing. The study is presented in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. This systematic review was conducted using electronic databases such as PubMed, Scopus, Web of Science, and Science Direct. The grey literature search was conducted in the New York Academy of Medicine Grey Literature Report. All the studies in this systematic review were randomized controlled trials (RCTs). The risk of bias was performed according to the Cochrane Handbook for Systematic Reviews of Interventions 6.2 (RevMan 6.2). Considering the inclusion and exclusion criteria, we included 17 randomized clinical trials, published up to 2022 investigating the efficacy of PRF in post-exodontic bone regeneration. Based on the results of clinical studies, it can be stated that despite not being statistically significant, PRF promotes neoformation and prevents bone loss between three and four months post-extraction.

Cytokines secreted by individual immune cells regulate tissue regeneration and allow communication between various cell types. Cytokines bind to cognate receptors and trigger the healing process. Determining the orchestration of cytokine interactions with their receptors on their cellular targets is essential to fully understand the process of inflammation and tissue regeneration. To this end, we have investigated the interactions of Interleukin-4 cytokine (IL-4)/Interleukin-4 cytokine receptor (IL-4R) and Interleukin-10 cytokine (IL-10)/Interleukin-10 cytokine receptor (IL-10R) using in situ Proximity Ligation Assays in a regenerative model of skin, muscle and lung tissues in the mini-pig. The pattern of protein-protein interactions was distinct for the two cytokines. IL-4 bound predominantly to receptors on macrophages and endothelial cells around the blood vessels while the target cells of IL-10 were mainly receptors on muscle cells. Our results show that in situ studies of cytokine-receptor interactions can provide unravel the fine details of the mechanism of action of cytokines.

Porous tantalum (Ta) is a promising biomaterial and has been applied in orthopedics and dentistry for nearly two decades. The high porosity and interconnected pore structure of porous Ta promise fine bone ingrowth and new bone formation within the inner space, which further guarantee rapid osteointegration and bone-implant stability in long term. Porous Ta has high wettability and surface energy that can facilitate adherence, proliferation and mineralization of osteoblasts. Meanwhile, low elastic modulus and high friction coefficient of porous Ta can effectively avoid stress shield effect, minimize marginal bone loss and ensure primary stability. Accordingly, the satisfactory clinical application of porous Ta based implants or prostheses are mainly derived from its excellent biological and mechanical properties. With the advent of additive manufacturing, personalized porous Ta based implants or prostheses have shown their clinical value in the treatment of individual patient who need specially designed implant or prosthesis. In addition, many modification methods have been introduced to enhance the bioactivity and antibacterial property of porous Ta with promising in vitro and in vivo research results. In any case, choosing suitable patients is of great importance to guarantee surgical success after porous Ta insertion.

The development of biomaterial as substitution to connective tissue graft for treating gingival recession is growing nowadays. Hydrogels received attention as potential scaffold to be used in gingival tissue engineering since their capability to mimic soft tissue characteristic as they can hold amount of water. Gelatin is a natural polymer that widely used in hydrogel preparation with good biological properties, but it has poor physical stability for the used as scaffold. Chemical crosslinking strategy using EDC/NHS was performed in this study to overcome its limitation. One uncrosslinked gelatin and two crosslinked gelatin hydrogels different concentration of EDC/NHS were prepared in this study. This study investigated the difference of physical characterization from the prepared gelatin hydrogels. Our findings suggest the crosslinking strategy using EDC/NHS increase physical properties of the gelatin hydrogels without interfering the chemical structure of the gelatin. The higher crosslinker concentration will result in better morphology and more resilient to biodegradation. As a result, the crosslinked gelatin hydrogel with gelatin:EDC:NHS mass ratio of 12:1:1 met the physical characteristic for future use as scaffold for gingival tissue regeneration.

The objective of this case report is to introduce a customized CAD/CAM freeze-dried bone allograft (FDBA) block for its use in Guided Bone Regeneration (GBR) procedures for severely deficient maxillary bones. Additionally, a special newly developed remote incision technique is presented to avoid wound dehiscence. The results show an optimal integration behaviour of the FDBA block after six months and the formation of new vital bone. Thus, the results of the present case report confirm the use of the customized CAD/CAM bone block for augmentation of complex defects in the maxillary aesthetic zone as a successful treatment concept.

Dysregulation of cartilage homeostasis and the changes in the density and the architecture of the subchondral bone were postulated as a potent mechanically pathological activity contributing to osteoarthritis (OA) pathogenesis. Extracorporeal shockwave therapy (ESWT) is a new, none invasive and effective method in the treatment of animal OA model. In the current study, we demonstrated that shockwave induced the expression of protein-disulfide isomerase-associated 3 (Pdia-3) which is a multifunctional protein hypothesized to be a significant mediator for 1α,25-Dihydroxyvitamin D3 (1α,25(OH)₂D₃) signaling pathway using two-dimensional electrophoresis. Histological analysis and quantitative polymerase chain reaction (qPCR) were verified and observed that the expression of Pdia-3 at 2 weeks was significantly higher than that of any other group at 4 weeks, 8 weeks, and 12 weeks post-shockwave treatment in early OA knee of rat. The other factors of the 1α,25(OH)₂D₃ rapid membrane signaling pathway including extracellular signal-regulated protein kinases 1 (ERK1), osteopontin (OPG), alkaline phosphatase (ALP), and matrix metallopeptidase 13 (MMP13) were measured and significantly increased by qPCR at 2 weeks post-shockwave treatment in early OA knee. Our proteomic data revealed significant Pdia-3 expression in microenvironments of joint tissue that could be actively responded to ESWT, which may potentially regulate biological function of chondrocytes and osteoblasts in the treatment of OA knee.

This study aimed to evaluate the physico-chemical properties, biocompatibility and bioabsorption of 3 different new membranes for bone guided regeneration (PLGA associated with hydroxyapatite and beta-TCP) with three thicknesses (200, 500 and 700 µm) implanted in mice subcutaneously. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and the quantification of Carbon, Hidrogen and Nitrogen were used to characterize the physico-chemical properties. One hundred Balb-C mice were divided into 5 experimental groups: Group 1 - Sham (without implantation); Group 2 - 200 μm; Group 3 - 500 μm; Group 4 - 700 μm; and Group 5 - Pratix®. Each group was subdivided into four experimental periods (7, 30, 60 and 90 days). Samples were collected and processed for histological and histomorphometrical evaluation. The membranes showed no moderate or severe tissue reactions in the experimental periods studied. The 500 μm membrane did not show tissue reaction for any experimental periods studied. The 200 μm membrane membranes began to exhibit fragmentation after 30- day, while the 500 and 700 µm membranes started the fragmentation at 90-day. All membranes studied were biocompatible, and the 500µm membrane showed the best results being a promissory membrane for bone guided regeneration.

Methacrylated silk (Sil-MA) is a chemically modified silk fibroin specifically designed to be crosslinkable under UV light. This allows the structuring of this material throught additive manufacturing techniques and then to easily prototype patient specific construct. In this study we used Sil-MA to produce single layer crosslinked structures that can be withdrawal and ejected recovering their shape after rehydration. A complete chemical and physical characterization of the material has been conducted. Additionally, we tested the material biocompatibility according to the International Standard Organization protocols (ISO 10993) ensuring the possibility to use it in future trials. The material was also tested to verify its ability to support the osteogenesis. Two different additive manufacturing techniques have been tested (a Digital Light Processing (DLP) UV projector and a pneumatic extrusion technique) to develop Sil-MA grid. Finally, we provide a proof-of-concept that the printed Sil-MA structures are injectable.

Background : Newly generated cardiomyocytes (NGC) concur to recovery of human myocarditis. However, Methods: We retrospectively assessed NGC in 213 consecutive patients with endomyocardial biopsy denoting acute myocarditis, with normal coronaries and valves. Tissue samples were processed for histology (H&E), immunohistochemistry for the evaluation of inflammatory infiltrates, immunostaining for alpha-sarcomeric-actin, junctional connexin-43, Ki-67, phosphorylated STAT3 (p-STAT3) and Western Blot (WB) for HMGB1. Frozen samples were analyzed with polymerase chain reaction (PCR) for cardiotropic viruses. Controls included 20 normal surgical biopsies. Results: NGCs were defined as small myocytes (diameter < 10 µm) with nuclear positivity to Ki-67 and p-STAT3, positive immunostaining for cytoplasmic α-sarcomeric actin and connexin 43. Their number/mm2 in relation with age and pathway of integration were evaluated. NGCs crossed the membrane and grew integrated within the empty necrotic myocytes. NGC mean diameter was 6.6 ± 3.34 vs 22.5 ± 3.11 µm adult cells; their number, in comparable LVEF, was 86.3 ± 10.3/mm2 in patients between 10 and 40 years; 50.4 ±13.8/mm2 in those between 41 and 60; 15.1 ± 5.7/ mm2 in those between 61 and 80; control NGC mean diameter was 0.2± 0.2/mm2. PCR was positive for viral genomes in 16% of cases; NGCs were not statistically different in viral and non-viral myocarditis. WB analysis revealed a higher expression of HMGB1 in myocarditis compared to myocardial controls. Conclusions: NGCs are constantly recognizable in acute human myocarditis. Their number declines with age. Their integration within necrotic myocytes consents preservation of cardiac structure and function.

3D Printing (3DP) technology has revolutionized the field of the use of bioceramics for maxillofacial and periodontal applications, offering unprecedented control over the shape, size, and structure of bioceramic implants. In addition, bioceramics have become attractive materials for these applications due to their biocompatibility, biostability, and favorable mechanical properties. However, despite their advantages, bioceramic implants are still associated with inferior biological performance issues after implantation, such as slow osseointegration, inadequate tissue response, and increased risk of implant failure. To address these challenges, researchers have been developing strategies to improve the biological performance of 3D printed bioceramic implants. The purpose of this review is to provide an overview of 3DP techniques and strategies for bioceramic materials designed for bone regeneration. The review also addresses the use and incorporation of active biomolecules in 3D printed bioceramic constructs to stimulate bone regeneration. By controlling the surface roughness, and chemical composition of the implant, the construct can be tailored to promote osseointegration and reduce the risk of adverse tissue reactions. Additionally, growth factors, such as bone morphogenic proteins (rhBMP-2) and pharmacologic agent (dipyridamole), can be incorporated to promote the growth of new bone tissue. Incorporating porosity into bioceramic constructs can improve bone tissue formation and the overall biological response of the implant. As such, by employing surface modification, combining with other materials, and incorporation of 3DP workflow can lead to better patient healing outcomes.

Electrospinning is the versatile technique to generate large quantities of micro- or nano-fibers from a wide variety of shapes and sizes of polymer. Natural bone is a hierarchically composites with the dispersion of inorganic ceramic along organic polymer. The aim of this study, the electrospun poly (lactic acid) (PLA) mats coated with chitosan (CH) and calcium silicate (CS) powder were fabricated. The morphology, chemical composition, and surface properties of CS/CH-PLA composites were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, the CS/CH-coated PLA mats increased the formation of apatite on the surface when soaking in cell cultured medium. During culture, the adhesion and proliferation of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA were significantly promoted relative to those on PLA. Collagen I and fibronectin levels and promoted cell adhesion were observed upon an increase in CS content. Further, compared to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs as well as their osteogenesis properties, which was characterized by bone-related gene expression. Our results demonstrated that the biodegradable and electroactive CS/CH-PLA mats had potential application as an ideal candidate for bone tissue engineering. Together, findings from this study clearly demonstrated that PLLA-C2S composite scaffold may function as an ideal candidate for bone tissue engineering.

Background: The implementation of tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML) has brought a significant improvement in the prognosis for CML patients and a decrease in the number of patients requiring allogeneic hematopoietic stem cell transplantation (allo-HCT). Nevertheless, the impact of TKIs on allo-HCT outcomes have not been thoroughly explored. Objectives: The main endpoint of our research was to assess the impact of prior TKI treatment on acute graft-versus-host disease (aGvHD) and chronic graft-versus-host disease (cGvHD). Methods: In our retrospective analysis we included 240 patients treated between 1993 and 2013, and divided them into 3 groups according to the therapy administered prior to matched related or matched unrelated donor allo-HCT (imatinib group n=41, dasatinib/nilotinib group n=28, TKI naïve group n=171). Results: Both the cumulative incidence of aGvHD (p=0.044) and cGvHD (p&lt;0.001) in individuals receiving second generation TKIs (2G-TKIs) prior to allo-HCT compared to patients receiving no TKIs or imatinib (IMA) (40.7% vs 61.4% vs 70.7%, p=0.044; 25.0% vs 76.4% vs 51.2%, p&lt;0.001, respectively). In case of the 2G-TKI cohort, the number of low-grade aGvHD and cGvHD was significantly lower compared to the IMA and TKI-naïve groups (p=0.018, p=0.004; p&lt;0.001 versus TKI-naïve, respectively). In terms of 3-year overall survival (OS) there were no important variations between TKI-naïve, IMA and 2G-TKI (55% vs 49.9% vs 69.6%, p=0.740). Conclusions: The results of our study suggest that TKI treatment prior to allo-HCT may have protective impact on immune-mediated outcomes.

Adipose stem cells (ASCs) have multilineage differentiation capacity and hold great potential for regenerative medicine. Compared to bone-marrow-derived mesenchymal stem cells (bmMSCs), ASCs are easier to isolate from abundant sources with significantly higher yields. It is generally accepted that bmMSCs show age-related changes in their proliferation and differentiation potentials, whereas this aspect is still controversial in the case of ASCs. In this review, we evaluated the existing data on the effect of donor age on the osteogenic potential of human ASCs. Overall, a poor agreement has been achieved because of inconsistent findings in the previous studies. Finally, we attempted to delineate the possible reasons behind the lack of agreements reported in the literature. ASCs represent a heterogeneous cell population and the osteogenic potential of ASCs can be influenced by donor-related factors such as age, but also gender, lifestyle, and the underlying health and metabolic state of donors. Furthermore, future studies should consider experimental factors in in-vitro conditions, including passaging, cryopreservation, culture conditions, variations in differentiation protocols, and readout methods.

Hybrid scaffolds based on bioactive glass (BAG) particles (<38µm), covalently linked to the gelatin (G*), using 3-glycidoxypropyltrimethoxysilane (GPTMS), have been studied for bone bioengineering. In this study, two glass compositions (13-93 and 13-93B20 [where 20% of the SiO2 was replaced with B2O3]) were introduced in the gelatin matrix. The Cfactor (Gelatin/GPTMS molar ratio) was kept constant at 500. The hybrids obtained were found to be stable at 37°C, in solution; condition at which pure gelatin is liquid. All hybrids were characterized by in vitro dissolution in TRIS solution (for up to 4 weeks) and Simulated Body Fluid (SBF) (for up to 2 weeks). Samples processed with 13-93B20 exhibit a faster initial dissolution and significantly faster precipitation of a hydroxyapatite (HA) layer. The faster ion release and HA precipitation recorded from the G*/13-93B20 samples, is attributable to the higher reactivity of borosilicate compared to the silicate glass. MC3T3-E1 cells behavior, in direct contact with the hybrids, was investigated, showing that the cells were able to proliferate and spread on the developed biomaterials. Tailoring the glass composition allows to better control the material’s dissolution, biodegradability, and bioactivity. Bioactive (especially with 13-93B20 BAG), and biocompatible, the hybrids are promising for bone application.

Recombinant human collagen peptide (RCP) is a recombinantly created xeno-free biomaterial enriched in RGD (arginine-glycine-aspartic acid) sequences, with good processability that is being investigated for regenerative medicine applications. Recently, the biocompatibility and osteogenic ability of β-TCP/RCP (RCP granules combined with β-tricalcium phosphate (TCP) submicron particles) were demonstrated. In the present study, β-TCP/RCP was implanted into experimental periodontal tissue defects (three-walled bone defect) created in beagle dogs to investigate tissue responses and subsequent regenerative effects. Micro computed tomography image analysis at 8 weeks postoperatively showed that the amount of new bone after β-TCP/RCP graft was significantly greater (2.2 fold, P&lt;0.05) than that of the control (no graft) group. Histological findings showed that the transplanted β-TCP/RCP induced active bone-like tissue formation including TRAP-positive and OCN-positive cells as well as bioabsorbability. Ankylosis did not occur, and periostin-positive periodontal ligament-like tissue formation was observed. Histological measurements revealed that β-TCP/RCP implantation formed 1.7-fold more bone-like tissue and 2.1-fold more periodontal ligament-like tissue than the control, and significantly suppressed gingival recession and epithelial downgrowth (P&lt;0.05). These results suggest that β-TCP/RCP is effective as a periodontal tissue regenerative material.

In recent decades, porous scaffolds for bone tissue engineering (BTE) have gained significant attention. Considerable research efforts have been dedicated to investigating the impact of scaffold pore size on a diverse array of biological processes, including cell-scaffold interactions, substance transportation, and vascularization. However, the multi-scale hierarchical porosity, a key structural characteristic of natural bone, has rarely been replicated in BTE scaffolds due to the challenges of controlling the scaffold structure across multiple length scales. With the advancement of manufacturing technology, there has been increasing research on biomimetic multi-scale hierarchical materials, which are also gaining favor in the field of BTE. Therefore, there is an urgent need to review multi-scale hierarchical porous BTE scaffolds. This paper aims to review the role and fabrication methods of multi-scale porous BTE scaffolds at different length scales, the design and manufacturing of new BTE scaffolds for bone regeneration.

The impact of obesity upon bone metabolism is controversial since both negative and positive effects have been reported. Bone remodeling is modulated by the central nervous system through cytokines, hormones and neuromodulators. The present study aimed to evaluate the effects evoked by bilateral retroperitoneal white adipose tissue (rWAT) denervation (Dnx) upon bone mineral metabolism and remodeling in an experimental model of obesity in rats. Male Wistar rats were fed during 18 weeks with high-fat diet (HFD) or standard diet (SD) as controls, and rWAT Dnx or Sham surgery was performed at the 14th week. Biochemical and hormonal parameters, bone histo-morphometry, rWAT and hypothalamus protein and gene expression were analyzed. HFD group presented decreased bone formation parameters, increased serum and bone leptin and FGF23, increased serum and hypothalamic neuropeptide Y (NPY) and decreased serum 1,25-dihydroxyvitamin D3 and PTH. After rWAT Dnx, bone markers and histomorphometry showed restoration of bone formation, serum and hypothalamic NPY decreased, without altera-tion in leptin levels. The present study showed that the denervation of rWAT improved bone formation in obese rats mediated by a preferential reduction in neurohormonal actions of NPY, emphasizing the relevance of the adipose tissue-brain-bone axis in the control of bone metabolism in obesity.

Background: Antibiotic-containing carrier systems are one option that offers the advantage of releasing active ingredients over a longer period of time. In vitro sustained drug release from a carrier system consisting of microporous β-TCP ceramic and alginate has been reported in previous works. Alginate dialdehyde (ADA) gelatin gel showed both better mechanical properties when loaded into a β-TCP ceramic and higher biodegradability than pure alginate. Methods: Dual release of daptomycin and BMP-2 was measured on days 1, 2, 3, 6, 9, 14, 21, and 28 by HPLC and ELISA. After release, the microbial efficacy of the daptomycin was verified and the biocompatibility of the composite was tested in cell culture. Results: Daptomycin and the model compound FITC protein A (n=30) were released from the composite over 28 days. A Daptomycin release above the minimum inhibitory concentration (MIC) by day 9 and a burst release of 71.7 ± 5.9 % were observed in the loaded ceramics. Low concentrations of BMP-2 were released from the loaded ceramics over 28 days.

Large volume bone defect regeneration is complex and demands time to complete. Several regeneration phases with unique characteristics including immune responses follow, overlap, and interdepend on each other and, if successful, lead to the regeneration of the organ bone's form and function. However, during traumatic, infectious, or neoplastic clinical cases, the intrinsic bone regeneration capacity may exceed, and surgical intervention is indicated. Scaffold-guided bone regeneration (SGBR) has recently shown efficacy in preclinical and clinical studies. To investigate different SGBR strategies over periods of up to 3 years we have established a well characterized large segmental tibial bone defect ovine model, for which we have developed and optimized immunohistochemistry (IHC) protocols. We present an overview of the immunohistochemical characterization of different experimental groups in which all ovine segmental defects were treated with a bone grafting technique combined with a three-dimensionally printed medical-grade polycaprolactone-tricalcium phosphate (mPCL-TCP) scaffold. The qualitative data set is based on osteoimmunological findings gained from IHC analyses of over &gt;350 sheep surgeries over the past two decades. Our systematic and standardized IHC protocols enabled us to gain further insight into the complex and long-drawn-out bone regeneration processes, which ultimately proved to be a critical element for successful translational research.

Regeneration of lost tail is of great importance to lizards. Anolis carolinensis, a green lizard, is capable of regenerating its tail efficiently after autotomy. Hence, it is considered as a model organism in regeneration study. A. carolinensis shed its tail in order to distract the predator’s attention and thus makes a way to escape. Restoring of the amputated tail takes several days and the mechanism is currently clearly understood. Although save its life, tail regeneration is associated with the impairment of several vital functions in Anoles. In addition, various differences have been observed between original and regenerated tail in terms of mechanism and structure. To date, very little work has been conducted on tail autotomy and regeneration at molecular and genetic level. The genes responsible for regeneration in anoles are identified recently. These genes are evolutionarily conserved through all tetrapod vertebrates. They are, however, in a state of ‘switched-off’ in other vertebrates including humans. Consequently, a throughout study of these so called ‘switched-off’ genes may provide a way of restoring lost organs in human, and thus could revolutionize the modern medical science.

Insufficient oral ridge tissue presents a challenge in the treatment of dental implants. One method to enhance alveolar crest dimensions is guided bone regeneration (GBR); however, existing membranes have certain limitations. To address this issue, we aimed to compare the effectiveness of a resorbable bilayer membrane composed of poly(l-lactic acid) and poly(-caprolactone) （PLACL）with that of a collagen membrane（COL） in a rat GBR model. The rat calvaria was used as an experimental model by placing a plastic cylinder. Forty male Fisher rats underwent surgery, and micro-computed tomography and histomorphometric analyses were performed to assess bone regeneration. The results showed that bone regeneration was similar across all the groups. However, after 24 weeks, the PLACL membrane demonstrated significant resilience, occasional partial degradation, and intermittent air bubble formation. This extended preservation of the barrier effect has great potential to facilitate optimal bone regeneration. In conclusion, this study shows that the PLACL membrane is a promising alternative to GBR. By providing a durable barrier and supporting bone regeneration over an extended period, this resorbable bilayer membrane may address the limitations of the current membranes. Further studies and clinical trials are warranted to validate the efficacy and safety of this drug in humans.

Tissue engineering and regenerative medicine has gradually evolved as a promising therapeutic strategy to the modern healthcare of the aging and diseased population. In this study, we developed a novel nano-fibrous scaffold and verified its application in the critical bone defect regeneration. The metformin-incorporated nano-gelatin/hydroxyapatite fibers (NGF) was produced by electrospinning, cross-linked, and then characterized by XRD and FTIR. Cytotoxicity, cells adhesion, cell differentiation, and quantitative osteogenic gene and protein expression were analyzed by bone marrow stem cells from rat. Rat forearm critical bone defect model was performed for the in vivo study. The nano-gelatin/hydroxyapatite fibers (NGF) were characterized by their porous structures with proper interconnectivity without significant cytotoxic effects; the adhesion of bone marrow stem cells on the nano-gelatin/hydroxyapatite fibers (NGF) could be enhanced. The osteogenic gene and protein expression were upregulated. Post implantation, the new regenerated bone in bone defect was well demonstrated in the NGF samples. We demonstrated that the metformin-incorporated nano-gelatin-hydroxyapatite fibers greatly improved healing potential on the critical sized bone defect. Although metformin-incorporated nano-gelatin/hydroxyapatite fibers had advantageous effectiveness during bone regeneration, further validation is required before it can be applied to clinical applications.

Introduction This study was conducted to validate the findings of a prior study published in JDD in September 2023, which reported that a topical firming and toning body lotion (FTB – SkinMedica®, Allergan Aesthetics, an AbbVie Company, Irvine, CA) upregulated several genes in a UV irradiated 3D full-thickness human skin model, outperforming other products, including TransFORM Body Treatment with TriHex Technology® (ATF – Alastin Skincare®, a Galderma company Fort Worth, Texas, USA ). Given the unique response reported for FTB, we conducted this study to assess the reproducibility of these results and explore gene expression at multiple time points, along with validating protein expression in an ex vivo model. Materials and Methods Experiments were conducted using an ex vivo model with photodamaged skin from facelift patients, under an Institutional Review Board approved study. Skin samples were processed, cultured in transwells with Skin Media, and treated daily with either TransFORM or FTB for 7 days. A control group was left untreated. Gene expression was assessed using RT-PCR on days 1 and 3, immunofluorescence after 3 and 7 days of treatment. Skin samples were fixed, paraffin-embedded, sectioned, and stained with an anti-tropoelastin antibody. Fluorescence detection and imaging were conducted to assess protein expression changes. Results Gene expression data from our study and the initial study showed a few similarities but multiple discrepancies. In particular, as opposed to results previously reported at only the 24-hour time point, additional time points showed complete reversal of many of these results. For example, COL1A1 expression at 24 hours was similar for FTB in both studies but differed for TransFORM which showed higher levels at 24 hours. However, at day 3, COL1A1 expression decreased markedly for FTB and was sustained for TransFORM. Other genes, such as COL3A1, COL5, ELN, VEGFC, ATG7, ATG12, BECN1, POMP, PSMB5, and PSMB6, exhibited varying expression patterns between the studies and across different time points. From a translational perspective, histological analysis showed that TransFORM enhanced elastin fiber presence in the dermal-epidermal junction (DEJ) more effectively than FTB at both day 3 and day 7. FTB-treated samples maintained a gap in the DEJ, while TransFORM-treated samples exhibited increased cellular proliferation and DEJ undulation, indicative of a healthier regenerative response. Conclusion This study highlights the problems of examining data and drawing conclusions using a single point of examination. In addition, when a study reports positive results for only 1 product among a range of 8 competitive products, further questioning is essential to exclude the possibility of the experimental model favoring that particular product. The additional 3-day timepoint and further translational examination of histological changes, paints a completely different picture to that reported in the prior publication TransFORM outperformed FTB in most gene expression and histological parameters when assessed over multiple time points in a physiologically relevant ex vivo model.

: Carcinoma-associated fibroblasts (CAFs) are highly accumulated in the tumor surrounding stroma of primary epithelial ovarian cancer (OC). CAFs exert important functions for the vascularization, growth and progression of ovarian tumor cells. However, no attention has been shown to their origin so far. It has been mainly assumed that CAFs in primary OC arise from the activation of resident fibroblasts. Here, we compare CAFs with ovarian location to CAFs found in peritoneal implants from patients with advanced OC. Our findings show that CAFs from primary tumors and peritoneal metastases share the expression of mesothelial-related markers. Therefore, as in peritoneal carcinomatosis, CAFs in primary ovarian carcinomas could be originated via a mesothelia-to-mesenchymal transition (MMT) process. The detection of mesothelial-derived CAFs in tumors confined to the ovary and associated biomarkers could be the key to early detection of peritoneal spread in affected patients.

Functional articular cartilage regeneration remains an unmet medical challenge, increasing the interest for innovative biomaterial-based tissue engineering (TE) strategies. Hydrogels, 3D macromolecular networks with hydrophilic groups, present articular cartilage-like features such as high water content and load-bearing capacity. In this study, 3D porous polyethylene glycol diacrylate (PEGDA) hydrogels were fabricated combining the gas foaming technique and an UV-based crosslinking strategy. The 3D porous PEGDA hydrogels were characterized in terms of their physical, structural and mechanical properties. Our results showed that the size of the hydrogels pores can be modulated by varying the initiator concentration. In vitro cytotoxicity tests showed that 3D porous PEGDA hydrogels presented high biocompatibility both with human chondrocytes and osteoblast-like cells. Importantly, the 3D porous PEGDA hydrogels supported the viability and chondrogenic differentiation of human bone marrow-derived mesenchymal stem/stromal cells (hBM-MSCs)-based spheroids as demonstrated by the positive staining of typical cartilage extracellular matrix (ECM) (glycosaminoglycans (GAGs)) and upregulation of chondrogenesis marker genes. Overall, the produced 3D porous PEGDA hydrogels presented cartilage-like mechanical properties and supported MSC-spheroid chondrogenesis, highlighting their potential as suitable scaffolds for cartilage TE or disease modelling strategies.

The employment of PRP in regenerative medicine has not generated the promised grandiose outcomes. Nonetheless, it currently remains the gold standard strategy for tissue regeneration. Therefore, scientific research has focused on identifying other matrices rich in growth factors and cytokines to improve the efficacy of PRP. In the present study, a new technology called AMPLEX PLUS -compound derived from colostrum enriched with exosomes- was applied in combination with PRP to evaluate the concentration trend of 20 bioactive molecules. The results show that the concentration of all the compounds analyzed increased significantly in PRP samples with AMPLEX PLUS technology compared with samples containing only plasma or PRP, suggesting how this new strategy could improve the performance of PRP and make significant advances in regenerative medicine.

The aim of this study was to evaluate the effects of autologous microfragmented adipose tissue (MFAT), obtained by mechanical fragmentation, on radiographic bone healing in dogs subjected to tibial plateau levelling osteotomy (TPLO). Twenty dogs with unilateral cranial cruciate disease were enrolled and randomly assigned to the treatment group (MFAT) or the control group (NT). The MFAT group underwent TPLO and autologous MFAT intra-articular administration while the NT group underwent TPLO alone. The adipose tissue was collected from the thigh region and MFAT was obtained by mechanical fragmentation at the end of the surgery. The patients were subjected to X-ray exam preoperatively, immediately postoperatively (T0) and at 4 (T1) and 8 (T2) weeks postoperatively. Two radiographic scores that had previously been described for the evaluation of bone healing after TPLO were used. A 12-point scoring system (from 0 = no healing to 12= complete remodelling) was used at T0, T1 and T2, while a 5-point scoring system (from 0 = no healing to 4 = 76%–100% of healing) was used at T1 and T2. The median healing scores were significantly higher at T1 and T2 for the MFAT group compared with the NT group for the 12-point (p < 0.05) and 5-point (p < 0.05) scoring systems. The intra-articular injection of autologous microfragmented adipose tissue can accelerate bone healing after TPLO without complications.

One-dimensional nanostructures such as silver nanowires (AgNWs) have attracted considerable attention owing to their outstanding electrical, thermal and antimicrobial properties; however, their application in the prevention of infections linked to bone tissue regeneration interventions has not yet been explored. Here we report on the development of an innovative scaffold prepared from chitosan, composite hydroxyapatite and AgNWs (CS-HACS-AgNWs) having both bioactive and antibacterial properties. In vitro results highlighted the antibacterial potential of AgNWs against both gram-positive and gram-negative bacteria. The CS-HACS-AgNWs composite scaffold demonstrated suitable Ca/P deposition, improved gel strength, reduced gelation time, and sustained Ag+ release within therapeutic concentrations. Antibacterial studies showed that the composite formulation was capable of inhibiting bacterial growth in suspension and of completely preventing biofilm formation on the scaffold in the presence of resistant strains. The hydrogels were also shown to be biocompatible, allowing cell proliferation. In summary, the developed CS-HACS-AgNWs composite hydrogels demonstrated significant potential as a scaffold material to be employed in bone regenerative medicine, as it presents enhanced mechanical strength combined with the ability to allow calcium salts deposition, while efficiently decreasing the risk of infections. The results presented justify further investigations into potential clinical applications of these materials.

Objectives. To compare the audiological benefits of a non-implantable wearing option of a bone conduction (BC) implant mounted on an arch (SoundArc) to traditional BC hearing aids (HA) mounted on eyeglasses (BCHA) in patients with moderate to severe conductive or mixed hearing loss. Methods: A preliminary cross-sectional observational prospective cohort study was conducted at a Tertiary Audiological Department, University Hospital. Fourteen adults with conductive or mixed hearing loss (PTA at 0.5-1-2-4 KHz = 67 ± 15 dB HL) had been wearing conventional BCHA on eyeglasses for at least 3 years, and refused the surgical implantation of a BC hearing implant (BCHI). Unaided and aided pure-tone AC and BC thresholds and speech test in quiet and in noise were recorded at baseline and in two different settings: with a BCHI mounted on SoundArc®, and with their own BCHA with two couplers, mounted on eyeglasses. International Inventory for Hearing Aids [IOI – HA], the Hearing Handicap Inventory [HHIA/E], Speech, Spatial, Qualities of Hearing Scale [SSQ], a 10-scores visuo-analogic scale [VAS], and Fatigue impact scale [FIS] score were asked in both conditions. Results: a statistical significative functional gain was observed for both settings. (p=.0001) Better speech perception performances in quiet and in noise were observed with SoundArc compared to their conventional BCHA on eyeglasses (word repetition score in noise improvement of +19.3 at SNR +10 dB, p=.002; + 12.1 at SNR 0 dB, p=.006; and +11.4 at SNR -10 dB, p=.002) No significant differences were found in IOI–HA, FIS, and HHIA/E scores, while significative better SSQ scores in all domains were reported for SoundArc. (p=.0038) Conclusions: Although patients were accustomed to their BCHA on eyeglasses, the non-implanted wearable option of the BCHI proved to be a viable alternative in adult patients with conductive or mixed hearing loss unable to receive or refusing BCHI surgery.

PARP inhibitors are used in tumor therapy exploiting their inhibitory role in DNA repair. Radiation therapy leads to DNA damage in the affected region comprising both tumor tissue and adjacent normal tissue. In addition, radiotherapy has long-standing effects on DNA integrity. The mechanisms for this are not well understood. We studied normal tissue damage of the lung after application of ionizing radiation (IR) in two well established rat models comprising both external (eIR) and internal (iIR) ionizing radiation. We found a nearly complete (~350-fold) loss of PARP-1 in the irradiated tissue in both models but no change in PARylated protein. This may be explained by the strong decrease in both ARH3 and PARG, both deparylating enzymes. We demonstrate, that of all these proteins are expressed in type II pneumocytes, but also in type I pneumocytes and the bronchiolar epithelium. The data suggest a severe disturbance of PARylation in these cells which may affect their major functions such as maintenance of the integrity of the alveolar wall. It is likely that the application of PARP inhibitors could have cumulative effects in radiation-damaged normal tissue.

Objective. The present study examined the potential use of computed tomography panoramic mandibular indices on cone beam CT (CBCT) for the assessment of bone density in postmenopausal women with low bone mass. Study design. We enrolled 104 postmenopausal women who performed dual energy X-ray absorptiometry (DXA) using a DXA scanner and mental foramen region CBCT using NewTom VGi EVO Cone Beam 3D system. We assessed the relationship between DXA parameters: lumbar, femoral neck and total hip T score, bone mineral density (BMD), and lumbar trabecular bone score (TBS) and the panoramic mandibular indices: computed tomography mandibular index superior (CTI(S)), computed tomography mandibular index inferior (CTI(I)) and computed tomography mental index (CTMI). Results. We found important correlations between the CTI(I), CTI(S) and CTMI and bone mass, quantitative evaluated as BMD and T-score and also quality using TBS score. Conclusion. CBCT measured indices CTI(S), CTI(I), CTMI are useful in assessing patients with low bone mass.

Abstract: A biomaterial is proposed for closing extensive bone defects in the maxillofacial region. The composition of the biomaterial includes high-molecular chitosan, chondroitin sulfate, hyaluronate, heparin, alginate and inorganic nanostructured hydroxyapatite. The purpose of the study is to demonstrate morphological and histological early signs of reconstruction of a bone cavity of critical size. The studies were carried out on 84 white female rats weighing 200-250 g. The study group consisted of 84 subjects in total, 40 in the experimental group and 44 in the control group. In all animals, three-walled bone defects measuring 0.5 x 04 x 05 cm were applied subperiosteally in the region of the angle of the lower jaw and filled in experimental group using lyophilized gel mass of chitosan-alginate-hydroxyapatite (CH-SA-HA). In control animals, the bone cavities were filled with an auto-blood clot after bone trepanation and bleeding. The observation periods are 3.5.7 days, 2.3.4.6.8 and 10 weeks. The control of bone regeneration was carried out using multiple morphological and histological analyses. Results showed that following implantation the chitosan construct actively replaced early-stage defects with the formation of a full-fledged new bone tissue as compared to the control group. Already, by the 7th day morphological analysis showed that formation of spongy bone tissue could be seen. After 2 weeks there was a pronounced increase in bone volume (P<0.01), and at 6 weeks after surgical intervention the closure of the defect was 70-80%, after 8 weeks - 100% without violation of bone morphology with a high degree of mineralization. Thus, the use of modified chitosan after filling eliminates bone defects of a critical size in the maxillofacial region, reveals early signs of bone regeneration, and serves as a promising material in reconstructive dentistry.

Glycosphingolipids (GSLs), a subtype of glycolipids containing sphingosine, are critical components of vertebrate plasma membranes, playing a pivotal role in cellular signaling and interactions. In human articular cartilage in osteoarthritis (OA), GSL expression is known notably to decrease. This review focuses on the roles of gangliosides, a specific type of GSL, in cartilage degeneration and regeneration, emphasizing their regulatory function in signal transduction. The expression of gangliosides, whether endogenous or augmented exogenously, is regulated at the enzymatic level, targeting specific glycosyltransferases. This regulation has significant implications for the composition of cell surface gangliosides and their impact on signal transduction in chondrocytes and progenitor cells. Different levels of ganglioside expression can influence signaling pathways in various ways, potentially affecting cell properties, including malignancy. Moreover, gene manipulations against gangliosides have been shown to regulate cartilage metabolism and chondrocyte differentiation in vivo and in vitro. This review highlights the potential of targeting gangliosides in the development of therapeutic strategies for osteoarthritis and cartilage injury and addresses promising directions for future research and treatment.

In the ongoing shift towards electric vehicles (EVs) primarily utilizing lithium-ion battery technology, a significant population of hybrid electric vehicles (HEVs) remains operational, reliant on established NiMH battery systems. Over the last twenty years, these HEVs have generated a substantial quantity of NiMH batteries that are either inoperable, experiencing performance degradation, or approaching the end of their service life. This results in a twofold challenge: a growing volume of environmentally hazardous waste due to the difficulty of NiMH battery reclamation, and escalating maintenance costs for HEV owners necessitated by replacement battery purchases. Patent WO2015092107A1, published in 2015, proposed a "Method for regenerating NiMh batteries." This method claims the ability to restore NiMH batteries to their original functionality. However, a comprehensive review of relevant scientific literature fails to identify any empirical evidence supporting the efficacy of the regeneration technique detailed in the patent. Within this context, this paper presents a detailed analysis and evaluation of the feasibility of the aforementioned patented method. To achieve this objective, the authors propose a prototype constructed utilizing NiMH battery cells sourced from a Toyota Prius. The experimental results obtained from this prototype demonstrate the potential for battery regeneration using the proposed method. These findings offer a promising solution for mitigating the challenges associated with NiMH battery disposal and maintenance within the HEV domain.

Background: One challenge in implant dentistry is to reduce marginal bone resorption to avoid long-term esthetic and biological complications. Sub-gingival implant placement has been suggested as a suitable strategy. Methods: 38 healthy patients were enrolled to receive bone level (BL – Control group) or 2 mm sub-crestal (SC - Test group) conical connection, platform-switched implants. An immediate tissue level abutment was used in the Test group by following a One Time Abutment (OTA) restorative procedure. Marginal Bone Modification (MBM) was calcu-latied on standardized radiographs at surgery (T0), loading (T1), and 6 months (T2) and 12 months after loading (T3), and cathegorised in Bone Loss (BL) if the resorption occurred below the implant neck and Bone Remodeling (BR) if above. Pocket probing depth (PPD), Bleeding on probing (BoP) and Plaque Index (PI) were also collected. Results: The mean MBM in the test group after 12 months was 0.61mm, compared to 0.52mm in the control group. However, no BL was observed in the test group, as the MBM completely occurred above the implant neck as BR, whilst in the control group MBM corresponded in total to BL. The average PPD was 2.38mm in the test group and 3.04mm in the control group after 12 months, BoP 50% and 43%, PI 33% and 19.44% respectively. Conclusions: Sub-crestal conical connection, platform-switched implants could be a suitable clinical choice to avoid BL with exposure of the treated implants surfaces.

Methylmercury (MeHg) intoxication is a global health concern. Although MeHg neurotoxicity is well-recognized, less is known about MeHg's effects on metabolism. In this study, we evaluated MeHg intoxication (20mg/L in drinking water for 20 days) effects on liver and epididymal white fat (EWF) in young ApoE knockout (ko) and wild-type mice. The former is well-known to show spontaneous dyslipidemia. Hg levels in hair, liver, and EWF were measured to assess the degree of MeHg exposure. We also evaluated body weight gain, plasma triglycerides, total cholesterol levels, and liver injury by assessing steatosis score, AST, ALT, SOD, and TBAR levels. To evaluate EWF, we analyzed mean wet weight and adipocyte diameter, plasma leptin levels and metabolomics. Hg levels were markedly higher among intoxicated mice. ApoE ko mice showed higher Hg in the hair but lower levels in the liver and EWF than wild-type controls. Among wild-type mice, MeHg compromised weight gain and increased liver TBAR levels compared to non-challenged controls. Among non-intoxicated mice, ApoE deficiency significantly increased triglyceride, total cholesterol, and liver transaminases with reduced EWF wet weight, hepatic SOD, and plasma leptin levels. MeHg accumulation together with ApoE deficiency elevated total cholesterol, triglycerides, hepatic transaminases, and TBARS. We found distinct EWF metabolite activity in different scenarios of ApoE deficiency and MeHg intoxication, highlighting increased cardiovascular risk especially when both challenges occur. Further studies are required to elucidate the underlying mechanisms involved in these effects and the target nutritional interventions in most need to ameliorate them.

Biphasic bone substitutes (BBS) are nowadays established biomaterials. Through their constant development even natural components like hyaluronic acid (HY) are added to improve both their handling and also their regenerative properties. However, low knowledge exists regarding the consequences of the HY addition for their biocompatibility and the inflammatory tissue reactions. Thus, the present study was conducted aiming to analyze the influence of two different amounts of high molecular weight HY (HMWHY) combined with a BBS on the in vitro biocompatibility and the in vivo tissue reaction. Established in vitro procedures using L929 cells were used for cytocompatibility analyses under the test conditions of DIN EN:ISO 10993-5. For the in vivo study part, calvarial defects were created in 20 Wistar rats and subsequently filled with the BBS and the BBS combined with two different HMWHY amounts, i.e., BBS+HY(L) and BBS+HY(H). As controls empty defects were used. Established histological, immunohistochemical and histomorphometrical methods were applied to analyze the tissue reactions to the three different materials, including the induction of pro- and anti-inflammatory macrophages and multinucleated giant cells (BMGCs). The in vitro results showed that none of the materials or compositions caused biological damages to the L929 cells and can considered to be non-toxic. The in vivo results showed that only the addition of high doses of HY to a biphasic bone substitute significantly decreases the occurrence of proinflammatory macrophages (* p < 0.05) comparable to the numbers found in the control group, while no significant differences within the three study groups for M2-macrophages nor BMGCs were detected. In conclusion, the addition of different amounts of HMWHY does not seem to affect the inflammation response to the BBS while improving the material handling properties.

Tissue-like phantoms are widely used as a model for mimicking the optical properties of live tissue. This paper presents the results of a diffusion reflection method as well as fluorescence lifetime imaging microscopy measurements of fluorescein-conjugated gold nanorods in solution as well as inserted in solid tissue-imitating phantoms. A lack of consistency between the fluorescence lifetime results of the solutions and the phantoms raises a question about the ability of tissue-like phantoms to maintain the optical properties of inserted contrast agents.

Bacterial nanocellulose (BNC) surface has a negative charge that allows the adsorption of calcium ions to initiate the nucleation of different calcium phosphate phases. The aim of this study was to investigate different methods of mineralization on three-dimensional microporous bacterial nanocellulose, to mimetize the composition, structure, and biomechanical properties of natural bone. To generate 3D microporous biomaterial, the porogen particles were incorporated during the BNC fermentation with the strain Komagataeibacter medellinensis. Calcium phosphates (CPs) were deposited on BNC scaffolds by five alternating immersing cycles with calcium and phosphate solutions. Scanning electron microscopy micrograph showed that the scaffolds have different pore sizes, between 70 and 350 µm, but the porous interconnectivity was affected by the biomineralization method and time. The crystals on the BNC surface are shown to be rod-shaped with a calcium phosphate ratio similar to that of immature bone, increasing from 1.13 to 1.6 with cycle numbers. The main mineral phases obtained by X-ray diffraction were Octacalcium Dihydrogen Hexakis (phosphate (V)) Pentahydrate (OCP). In vitro cell studies showed good cellular adhesion and higher cell viability to 95% in all the scaffolds. Osteogenic differentiation of human bone marrow mesenchymal stem cells on the scaffolds was evaluated by bone expression markers like alkaline phosphatase, osteocalcin, and osteopontin. In conclusion, it is possible to prepare 3D BNC scaffolds with controlled microporosity, which could allow osteoblast adhesion, proliferation, and differentiation.

Disease, trauma, and aging account for a significant number of clinical disorders. Regenerative medicine is emerging as a very promising therapeutic option. The design and development of new cell-customized biomaterials able to mimic ECM functionalities represent one of the major strategy to control the cell fate and stimulate tissue regeneration. Recently, hydrogels have received a considerable interest for their use in the modulation and control of cell fate during regeneration processes. Several synthetic bioresponsive hydrogels are being developed in order to facilitate cell-matrix and cell-cell interactions. In this review new strategies and future perspectives of such synthetic cell microenvironment will be highlighted.

Regeneration is usually regarded as a unique plant or some animal species process. In reality, regeneration is a ubiquitous process in all multicellular organisms. It ranges from response to wounding by healing the wounded tissue to whole body neoforming (remaking of the new body). In a larger context, regeneration is one facet of two reproduction schemes that dominate the evolution of life. Multicellular organisms can propagate their genes asexually or sexually. Here I present the view that the ability to regenerate tissue or whole-body regeneration is also determined by the sexual state of the multicellular organisms (from simple animals like hydra and planaria to plants and complex animals). The above idea is manifested here by showing evidence that many organisms, organs, or tissues show inhibited or diminished regeneration capacity when in reproductive status compared to the same organism organs or tissues in nonreproductive conditions or by exposure to sex hormones.

Low back pain (LBP) is a significant global health issue, contributing to considerable disability and socioeconomic burdens. The degeneration of the human intervertebral disc (IVD) is a critical factor in the pathogenesis of LBP. Recent studies have emphasized the significance of its specific set of genes and extracellular matrix (ECM) in IVD health. The Noggin gene has emerged as a critical factor due to its high expression levels in healthy nucleus pulposus cells (NPCs) observed in our previous research. In this study, we investigated the hypothesis that decreased Noggin expression in NPCs is associated with IVD degeneration, contributing to LBP development. A lentivirus-mediated RNAi was applied to knockdown Noggin expression in primary NPCs from six human donors. Cell viability analysis, XTT assay, and cell apoptosis were conducted to reveal the effect after transduction. After two weeks, colony formation unit (CFU) assay was used to examine the anchor-independent growth ability of transduced cells. Additionally, qPCR was performed to quantify cellular anabolism and catabolism makers at the transcript level. The results showed lentivirus-mediated downregulation of Noggin suppressed cell growth, cell viability, and colony formation, and induced apoptosis in human NPCs in vitro. Noteworthy, it hindered cellular anabolism and enhanced catabolism activity in human NPCs after transduction. Our findings indicated that the degeneration of human IVD is possibly related to decreased Noggin expression in NPCs. This research provides valuable insights into the role of Noggin in IVD homeostasis and its implications for LBP treatment.

Increasing evidence suggests that prenatal exposure to opioids can adversely influence brain development, yet, limited data exists on the effects of opioid-exposure on preschool language development. Our study aimed to characterize the nature and prevalence of language problems in children prenatally exposed to opioids, and the factors that support or hinder language acquisition. A sample of 100 children born to pregnant women in methadone maintenance treatment and 110 randomly identified non-exposed children were studied from birth to age 4.5 years. At 4.5 years, 89 opioid-exposed and 103 non-exposed children completed the preschool version of the Clinical Evaluation of Language Fundamentals (CELF-P) as part of a comprehensive neurodevelopmental assessment. Children prenatally exposed to opioid had poorer receptive and expressive language outcomes at age 4.5 years compared to non-exposed children. After adjustment for child sex, maternal education, other pregnancy substance use, maternal pregnancy nutrition and prenatal depression, opioid exposure remained a significant independent predictor of children’s total CELF-P language score. Examination of a range of potential intervening factors showed that a composite measure of the quality of parenting and home environment at 18 months and early childhood education participation at 4.5 years were important positive mediators.

Cadaver bone is possibly the most common transplant material used today. Common types of cadaver bone transplants are freeze dried bone allografts and xenografts. In the case of freeze dried bone allograft transplants, it was theorized that these materials mineralize by way of osteoinduction and stimulating osteogenesis. However, these theories have been proven false. It has been proposed that these materials mineralize via osteoconduction however, there are no studies to support this hypothesis. This study was undertaken to determine how these transplants mineralize and what type of bone they produce. Materials and Methods: This study is a histological analysis of human cadaver bone graft healing from the incipient stages of mineralization through completed mineralization. All cadaver bone grafts used for evaluation in this study were particulate bone graft materials in the maxilla or mandible. No block grafts were evaluated. Results: The mineralization of cadaver bone transplants was produced by an inflammatory response to the transplanted tissue. The histologic findings of the mineralized bone produced by this process was sclerotic bone. No resorption of cadaver bone graft particles was found. When loaded the sclerotic bone was found to fail through an accumulation of microfractures.Conclusions: Particulate freeze-dried bone allografts and xenografts do not heal via the normal processes of mineralization. Cadaver bone grafts produce significant inflammation and are hypothesized to mineralize by a process termed antigenic ossification. The process of antigenic ossification produces sclerotic bone that is not capable of self-repair which can ultimately lead to bone failure.

The breast holds significant importance in women's lactation process. The breast has diverse tissues such as glandular, Cooper’s ligament, lactiferous ducts, adipose, muscles, and skin with various mechanical properties. Most soft tissues exhibit nonlinear, viscoelastic, and anisotropic mechanical behaviour. Stiffness is one of the commonly used mechanical properties for measuring mechanical behaviour in soft tissues. However, this is typically used in simplifying cases where analysis is limited to within the linear elastic region. Young’s modulus is the prevailing measure for quantifying stiffness in tissues. This systematic review examines commonly used techniques for mechanically characterising breast soft tissues to close the gap in the literature. Additionally, this systematic review summarises the mechanical behaviour of the breast tissues available in the literature and highlights the uncovered areas to understand the mechanical behaviour of breast tissues fully. These include a) more mechanical behaviour studies, allowing more accurate modelling for other applications, b) Viscoelastic analysis studies, and c) mechanical analysis on other breast tissues, such as the lactiferous duct, also known as the milk duct. The data obtained in the review can be used as inputs in computational models to analyse the behaviour of the breast tissues.

Vertical and horizontal bone augmentation is one of the most challenging techniques in bone engineering. The use of barrier membranes and scaffolds in guided bone regeneration (GBR) procedures is a common approach for the treatment of lost bone around teeth and dental implants. The aim of this study was to estimate the barrier effects of a synthetic poly (lactic acid/caprolactone) [P(PA/CL)] bilayer membrane for GBR, compared to a porcine collagen bilayer membrane, in the vertical augmentation model on 10–12-months old rat skull without periosteum. The HAp block (diameter: 4 mm, height: 3 mm, porosity:75%, average pore size:150 μm) was placed on the rat skull without a periosteum. The P(LA/CL) membrane (solid layer: 25 μm, porous layer: 175 μm) or the collagen membrane (solid layer, porous layer) was applied onto the HAp block. At 3, 6, and 12 weeks after the surgery, the incised tissues were fixed, decalcified, and stained with hematoxylin and eosin for histological evaluation. The P(LA/CL) membrane remained until 12 weeks and could achieve barrier effects to inhibit cellular invasion from the repositioned soft tissues. Local bone formation occurred in the interconnected pores of HAp at 6 weeks. On the other hand, the collagen membrane did not inhibit cellular invasion for its expansion until 3 weeks, and was absorbed until 6 weeks. The results indicated that the P(LA/CL) membrane might be effective in GBR as occlusive absorbable membrane.

Spider silks, renowned for their exceptional mechanical and biocompatible properties, offer significant potential as scaffolds in tissue engineering. This paper explores the feasibility of using spidroins, the primary proteins in spider silk, to develop scaffolds that closely mimic the extracellular matrix (ECM) essential for tissue regeneration. Spidroins (spider silk proteins) are particularly valuable due to their unique strength, elasticity, and biocompatibility, which support cellular growth and differentiation. The paper examines current methods for producing recombinant spider silk, including using unicellular hosts like E. coli and multicellular systems like transgenic plants and silkworms. It also examines current scaffolds that utilize spidroins and their shortcomings, such as immunogenicity and protein production, which must be urgently addressed for more practical and effective widespread biomedical applications. In addition, it stresses the need for further research to solve these challenges and fully realize the potential of spider silk in biomedical applications.

(1) Background : When placing implants in the maxillary posterior region with insufficient alveolar bone, a maxillary sinus elevation is necessary. Autogenous bone, though biologically ideal, poses risks and discomfort due to donor site harvesting. Block-type autogenous tooth bone graft material, made from the patient’s own extracted tooth, offers similar biological stability without these drawbacks; (2) Methods : This study observed the progress of 19 implant patients who were treated with maxillary sinus elevation procedures using block-type autogenous tooth bone graft material at the Daegu Catholic University Medical Center. Extracted teeth were processed into demineralized tooth block bone. After elevating the sinus membrane, implants and the tooth bone graft material were placed in the space, and the bony window was repositioned. Postoperative evaluations through clinical observation and radiographic imaging assessed sinus membrane elevation, alveolar bone height increase, and implant osseointegration; (3) Results : Results showed proportional increases in alveolar bone height to the graft material size, with long-term stability. No postoperative complications occurred, even with sinus membrane perforation, and implants remained stable; (4) Conclusions : The study concludes that maxillary sinus lifts using block-type autogenous tooth bone graft material provide excellent bone induction and biocompatibility, making it a highly beneficial method for both dentists and patients.

The color of carcass fat is an important factor in meat quality. To investigate the characteristics and changes in lipid metabolism of SAT in Mongolian cattle at 34 M of age compared with the control group, we evaluated the color, relative expression of genes associated with browning, and profiles of lipid metabolites by using qPCR and non-targeted lipidomics techniques. Overall, the yellowness value and relative expression of mitochondrial biogenesis–specific markers, thermogenic, UCP2, and beige adipocyte marker genes in the SAT of 34 M cattle were higher than those control (p &lt; 0.05). Using multivariate analysis, 172 significantly different lipids (SDLs) were identified. Triacylglycerols (TGs) and phosphatidylcholines (PCs) had high relative contents with abundant unsaturated fatty acids. The upregulation of TGs observed in the SAT of 34 M cattle mainly consisted of medium- and long-chain fatty acids. Pathway analysis demonstrated that 172 SDLs were primarily involved in glycerophospholipid, glycerolipid, ether lipid, and sphingolipid metabolism. In summary, yellow fat of naturally grazed cattle was impacted by many factors such as lipid metabolism, browning genes expression and age. These findings provide new insight into the characteristics and metabolic pathways of adipose tissue in natural grazing Mongolian cattle.

This study aimed to identify miRNA editing sites during adipose tissue development in Ningxiang pigs and analyze their characteristics and functions. Based on the small RNA-seq data from subcutaneous adipose tissue samples of Ningxiang pigs at four stages (30, 90, 150 and 210 days), we constructed a developmental atlas of the miRNA editome in adipose tissue of Ningxiang pigs. The characteristics and functions of this editome were further explored through bioinformatics analysis. The findings revealed that a total of 505 miRNA editing sites were identified with C-to-U editing types being the most prevalent, followed by U-to-C, A-to-G and G-to-U. Importantly, these four types of miRNA editing exhibited a base preference. The number of editing sites showed obvious differences among age groups, with the highest occurrence of miRNA editing events observed at 90 days of age and the lowest at 150 days of age. In the miRNA seed region, a total of 9 miRNA editing sites were identified with significant differences in editing levels (P &lt; 0.05), and located in ssc-miR-23a, ssc-miR-27a, ssc-miR-30b-5p, ssc-miR-15a, ssc-miR-497, ssc-miR-15b, and ssc-miR-425-5p, respectively. Target gene prediction and enrichment analysis revealed that the editing of miR-497 may potentially regulate fat deposition by inhibiting adipose synthesis via influencing target binding. These results provide new insights into the regulatory mechanism of pig fat deposition.

Ozonated sunflower oil (OSO) is an established therapeutic agent and nutraceutical harboring various therapeutic values, including antiallergic, derma-protective, and broad-spectrum antimicrobial activity. Conversely, the medicinal aspects of OSO for wound healing, tissue regeneration, and treatment of inflammation in dyslipidemia have yet to be fully elucidated. Herein, a comparative effect of OSO and sunflower oil (SO) was investigated to heal cutaneous wound and tissue regeneration of zebrafish impediment by carboxymethyllysine (CML) toxicity, following impact on hepatic inflammation and blood lipid profile. After OSO (final 2%, 1 μL) and SO's (final 2%, 1 μL) treatment, substantial healing was elicited by OSO in the cutaneous wound of zebrafish impaired by CML (final 25 mg). As an important event of wound healing, OSO scavenges the reactive oxygen species (ROS), rescues the wound from oxidative injury, and triggers the essential molecular events for the wound closer. Furthermore, the intraperitoneal injection of OSO was noted to counter the CML-induced adversity and prompt tissue regeneration in the amputated tail fin of zebrafish. Additionally, OSO counters the CML-induced neurotoxicity and rescues the zebrafish from acute mortality and paralysis, along with meticulous recovery of hepatic inflammation, fatty liver changes, and diminished ROS and proinflammatory interleukin (IL)-6 production. Besides, OSO efficiently ameliorated CML-induced dyslipidemia by alleviating the total blood cholesterol (TC), triglyceride (TG) and increasing high-density lipoproteins cholesterol (HDL-C). The outcome of multivariate assessment employing principal component analysis and hierarchical cluster analysis supports a superior therapeutic potential of OSO over SO against the clinical manifestation of CML. Conclusively, OSO owing to its antioxidant and anti-inflammatory potential, counters CML-induced toxicity and promotes wound healing, tissue regeneration, hepatoprotection, improved blood lipid profile, and survivability of zebrafish.

Corneal diseases are the third leading cause of blindness worldwide. There are numerous causes of corneal blindness, and the common treatment for this condition often involves corneal tissue transplantation, such as Descemet's Membrane Endothelial Keratoplasty (DMEK). DMEK has been established as the preferred surgical technique for the treatment of corneal endothelial disorders. The success of DMEK depends largely on the quality of the donor endothelial cells and the trans-plantation procedure. However, the scarcity of suitable donor tissue and the sensitivity of endo-thelial cells pose a major challenge. In recent years, tissue engineering has attracted attention as potential solutions to these problems. This review offers an outline of the current landscape of DMEK in the context of bioengineering, exploring various methodologies, advancements, and fu-ture prospects.

This study presents an innovative method for producing thermosensitive bio-ink from chitosan hydrogels saturated with carbon dioxide and agarose. It focuses on a detailed characterization of their physicochemical properties and potential applications in biomedicine and tissue engineering. The ORO test approved rapid regeneration of the three-dimensional structure of chitosan-agarose composites in the unidirectional bench press simulation test. The diffusion of dyes through chitosan-agarose hydrogel membranes strongly depended on the share of both polymers in the composite and the molecular weight of the dyes. Glucose, as a nutrient marker, also diffused through all membranes regardless of composition. Biocompatibility assessment using MTT tests on 46BR.1N fibroblasts and HaCaT keratinocytes confirmed the safety of the bioink. The regenerative potential of the bioink was confirmed by efficient cell migration, especially HaCaT. Long-term viability studies showed that chitosan-agarose scaffolds, unlike the agarose ones, support cell proliferation and survival, especially 14 days after bioink extrusion. Experiments in a skin wound model in mice confirmed the biocompatibility of tested dressing and the beneficial action of chitosan on healing. Studies on vessel formation in chicken embryos highlight the potential of the chitosan-agarose composition for enhancing proangiogenic effects. This composition meets all entry criteria and possesses excellent biological properties.

The study evaluated the regenerative responses of the lacrimal functional unit (LFU) after Lacrimal Gland (LG) ablation. The LG of Wistar rats were submitted to G1) partial LG ablation, G2) partial ablation and transplantation of an allogeneic LG, or G3) total LG ablation, (n=7-10/group). The eye wipe test, slit-lamp image, tear flow, and histology were evaluated. RT-PCR analyzed inflammatory and proliferation mediators. The findings were compared to naïve controls after 1 and 2 months (M1 and M2). G3 presented increased corneal sensitivity, and the 03 groups have shown corneal neovascularization. Histology revealed changes in LG, and corneal inflammation. In the LG, there was an increase in MMP-9 mRNA of G1 and G2 at M1 and M2 and RUNX-1 at M1 and M2 in G1 and RUNX-3 mRNA at M1 in G1, and in G2 at M2. TNF-α mRNA rose in the corneas of G1 and G2 at M2. There was an increase in the IL-1β mRNA in the Trigeminal Ganglion of G1 at M1. Without changes in tear flow or evidence of LG regeneration, LG ablation or grafting are unreliable models for dry eye or LG repair in rats. The surgical manipulation extended inflammation to the LFU.