Pulp necrosis remains a significant clinical challenge in dentistry, as current therapeutic approaches fail to achieve functional pulp regeneration. Extracellular vesicles (EVs), as crucial mediators of intercellular communication, offer new opportunities for regenerative strategies. In this study, we focus on CD24(+) human dental papilla cells (CD24(+) hDPCs), a functionally defined subpopulation previously characterized as having superior regenerative potential, and evaluate the regenerative potential of their derived EVs (CD24(+) EVs) in pulp-like tissue regeneration. CD24(+) EVs significantly enhanced the proliferation, migration, and osteo/odontogenic differentiation of human dental pulp stem cells (hDPSCs) and markedly promoted endothelial tube formation in vitro. In a treated dentin matrix (TDM)-based ectopic regeneration model, CD24(+) EVs increased cellular accumulation within the regenerated tissue and robust angiogenesis, inducing the formation of well-organized, highly vascularized pulp-like tissue with dense cellular architecture and positive DSPP expression. Together, these findings suggest that CD24(+) EVs concurrently enhance cell migration, odontogenic differentiation, and angiogenesis, and support a promising cell-assisted EV strategy grounded in functionally defined cellular subpopulations for pulp-like tissue regeneration.

Tooth morphogenesis is orchestrated by a complex interplay of signaling pathways and transcription factors that control cell proliferation, apoptosis, and differentiation, with the Wnt/β-catenin signaling pathway playing a pivotal role. However, the comprehensive regulatory mechanisms of Wnt/β-catenin signaling remain largely unclear. Smad7, a key antagonist of the TGF-β superfamily, is essential for maintaining tissue homeostasis and ensuring proper cellular function. Our previous study has demonstrated that Smad7 knockout in mice leads to impaired proliferative property of tooth germ cells, resulting in small molars. Here, we identified SMAD7 expression in human dental papilla and dental pulp, colocalized with β-CATENIN and cell proliferation-related proteins. RNA sequencing analysis revealed a significant reduction in Wnt signaling activity in Smad7-deficient mouse tooth germs. Using lentivirus transfection, we established SMAD7-knockdown human dental papilla stem cells, which manifested remarkably blunt proliferation rate, along with diminished Wnt signaling activity. In vivo transplantation investigations further revealed the indispensable role of SMAD7 in dentin formation. Mechanistically, we revealed that β-CATENIN interacts with P-SMAD2/3 and SMAD7 through co-immunoprecipitation and yeast two-hybrid assays. Inhibition of TGF-β pathway or disruption of SMAD7/β-CATENIN transcription factor complex formation potently impacted Wnt/β-catenin activities, indicating both direct and indirect regulatory mechanisms. These findings highlight the critical role of SMAD7 in the proliferation and differentiation of human dental stem cells, which could contribute to dental tissue regeneration and engineering.

In dental pulp regeneration, the ischemic microenvironment within the root canal severely compromises the survival and function of transplanted human dental pulp stem cells (hDPSCs). Here, we developed a PDMS-based core-shell oxygen-glucose delivery platform (P-C@P-G) that continuously released oxygen and glucose for up to 40 and 29 days, respectively, while minimizing peroxide-associated cytotoxicity through diffusion-controlled regulation without the need for exogenous enzymes. Under oxygen-glucose deprivation (OGD, 0.1% O2, glucose-free conditions) conditions, P-C@P-G improved cellular metabolic activity and enhanced hDPSC survival, proliferation, migration, and odontogenic differentiation. Compared with single-substrate supplementation, dual oxygen-glucose delivery produced greater improvements in hDPSC survival and differentiation. Transcriptomic and molecular analyses revealed alterations in TNF-α/NF-κB and Wnt/β-catenin signaling pathways following treatment. In vivo, P-C@P-G promoted pulp-like tissue regeneration, vascularization, and dentin sialophosphoprotein (DSPP) expression, resulting in greater pulp-like tissue formation and vascularization than the control group. Collectively, these findings demonstrated that sustained oxygen-glucose delivery effectively alleviated ischemia-associated metabolic insufficiency and revealed distinct contributions of oxygen and glucose to dental pulp regeneration.

Regeneration of the dentin-pulp complex is essential for tooth integrity and function. However, the inherent cell heterogeneity limits our understanding of lineage-specific subsets critical for efficient odontogenesis and regenerative outcomes. Here, we demonstrated that CD24+ human dental papilla cells (hDPCs) exhibit robust odontogenic differentiation capacity and drive coordinated regeneration of well-vascularized pulp and structurally integrated dentin tissues in both ectopic murine and preclinical in situ minipig models, significantly outperforming conventional dental pulp stem cells. Mechanistically, we delineate a BMP2/SIRT1 axis where elevated BMP signaling sustains SIRT1 expression and promotes mitochondrial metabolism and odontogenic capacity. Furthermore, BMP signaling induces VEGF expression, enhancing neovascularization via paracrine effects. CD24 is also a downstream marker of BMP signaling, though it does not directly mediate differentiation. Together, CD24+ hDPCs represent a regeneration-competent subpopulation that integrates mitochondrial metabolism and signaling crosstalk to enable coordinated dentin-pulp regeneration, representing a translationally relevant cell source for dental tissue engineering.

Cell sheet therapy has emerged as a transformative technology in regenerative medicine, providing scaffold-free constructs that preserve cell–cell junctions and extracellular matrix components. Compared with traditional cell delivery methods, cell sheets enable improved engraftment, survival, and integration after transplantation. Recent years have witnessed remarkable progress in clinical translation, with several products approved in Japan, the United States, and South Korea. This review summarizes the current landscape of cell sheet therapies approved worldwide, focusing on their fabrication technologies, cell sources, and clinical indications. We highlight representative products such as JACE®, Nepic®, Ocural®, JACEMIN®, HeartSheet®, Epicel®, Holoderm®, Kaloderm®, and ZEVASKYN™, emphasizing their technological foundations and regulatory trajectories. Advances in temperature-responsive culture surfaces, closed culture devices, and automated sheet manipulation have facilitated large-scale and standardized manufacturing. Furthermore, the establishment of cell banks, donor eligibility screening, and Good Manufacturing Practice (GMP)-compliant processes ensure product consistency and safety. In parallel, regulatory frameworks in Japan, the United States, and South Korea have shaped the development paths of autologous and allogeneic products, with different strategies for approval, reimbursement, and long-term monitoring. Cell sheet-based regenerative therapies have already demonstrated clinical and commercial viability, offering novel treatment options for burns, ocular diseases, vitiligo, and cardiac conditions. Despite encouraging outcomes, challenges remain in vascularization, large-scale production, cost-effectiveness, and equitable patient access. Continued progress will depend on addressing biological limitations, optimizing manufacturing logistics, and harmonizing international regulations. Collectively, cell sheet therapies represent a pivotal step toward broader adoption of regenerative medicine in routine clinical practice.

OBJECTIVE:Irreversible pulpitis in immature teeth is a serious dental disease which may lead to unclosed apical foramen and even tooth loss. Our study proposed a system of G-CSF/laponite/collagen composite and investigated its effects for stem cells of apical papilla (SCAPs) homing, targeting a potential treatment for immature dental pulp regeneration. METHODS:In vitro, the effect of G-CSF on SCAPs proliferation, migration and differentiation was investigated. The microporous scaffold structure, sustained-release capability and cytotoxic effects of G-CSF/laponite/collagen composite was evaluated. In vivo, dentin cannulas model filled with G-CSF/laponite/collagen composite implanted in the back of nude mice was utilized to verify the effects of SCAPs homing for pulp regeneration. RESULTS:In our study, the promoting effects of G-CSF on SCAPs proliferation and migration were verified, and the optimal concentration was chosen at 10 and 50 ng/ml. Interestingly, G-CSF had a slight effect on osteogenesis but significantly increased the gene expression of odontogenesis (DSPP, DMP-1). Laponite was observed to adsorb and slowly release G-CSF in a sustained manner, and the "laponite + collagen" contained micropore scaffold structure without biotoxicity for SCAPs. In vivo, 50 ng/ml G-CSF/laponite/collagen composite appeared to be the best combination for pulp regeneration, among the aspects of neo-tissue area, regenerative cells, odontoblast-like ratio, and number of blood vessels. CONCLUSION:Our study proposed that 50 ng/ml G-CSF/laponite/collagen composite has a great potential to induce SCAPs homing for immature dental pulp regeneration, providing a new strategy to treat irreversible pulpitis in immature teeth.

Insufficient blood circulation in injured regions is a critical challenge that hinders the application of engineered tissue in the regeneration of tissue defects or losses. Here, we developed a three-dimensional culture system that enables human microvascular units (MVUs) to expand and self-organize into vascularized microtissues containing well-formed microvascular structures and stem-cell-derived functional stroma. Moreover, the vascularized microtissue is customizable in both shape and size. The functionality of vascularized microtissues was evaluated in various tissue defect models including spinal cord injury, skin defects, and femoral bone defects. In vivo evidence confirmed that transplantation of customized vascularized microtissues efficiently enhanced nerve function and motor recovery in the spinal cord injury model, accelerated wound closure, facilitated skin appendage regeneration in the skin defect model, and boosted bone regeneration in the femoral defect model. These findings highlight the potential of vascularized microtissues as an efficient platform for repairing and regenerating diverse tissues.

Aim or purpose: The pulp regeneration strategy is important to treat pulpitis and pulp necrosis. Yet the key functional subpopulation and mechanism that governs the odontogenic fate decisions remain largely unknown. Materials and methods: In our study, a heterogeneous human CD24+ dental papilla stem cell with strong odontogenic differentiation potential was identified from dental papilla tissue through fluorescence-activated cell sorting, and the latent odontogenic mechanism was revealed through transcriptome analysis. Results: We found that CD24+ cells not only play a dominant role in deep caries defense but also functional pulp-dentin regeneration, which was verified by an ectopic pulp regeneration mice model and a clinical scale in situ minipig model. Transplantation of CD24+ cells efficiently reconstructed pulp tissue with robust neo-dentin formation and neovascularization that resembled the native pulp tissue. The success rate was significantly higher than dental pulp stem cells. Mechanistically, we proposed a novel regulatory paradigm, wherein BMP2-derived BMP signaling orchestrates SIRT1-mediated mitochondrial metabolic reprogramming to regulate the odontogenic fate commitment. Inhibition of BMP signaling led to the downregulation of SIRT1 expression, antioxidant capacity, autophagy, mitochondrial biogenesis, ultimately resulting in mitochondrial metabolic dysfunction and odontogenic fate impairment. Moreover, we unveiled that high BMP signaling activity upregulated VEGF expression in CD24+ cells, which enhanced HUVECs migration and angiogenesis during pulp regeneration. Conclusions: These findings unveiled promising insights into the specific therapeutic strategies based on human CD24+ dental papilla stem cells and mitochondrial metabolic manipulation, with novel and promising applications in pulpitis and pulp necrosis treatments.

Skeletal muscle regeneration mediated by muscle satellite cells (MuSCs) is supported by the specific vascular niche containing endothelial cells, pericytes, and mesenchymal stem cells. Volumetric muscle loss (VML) severely disrupts the vascular niche and impairs the ability of MuSCs to regenerate functional skeletal muscle. Until now, it remains a great challenge to reconstruct the vascular niche for muscle regeneration. Here, we successfully developed a specific 3D induction strategy based on collagen matrix and pro-angiogenic culture system to fabricate a multifunctional human pre-vascularized microtissue (h-VM) in vitro. The h-VM featured a robust vascular network formed by endothelial cells, with pericytes and mesenchymal stem cells accompanying. Under a specific induction medium, the h-VM could differentiate into adipogenic and osteogenic tissues, indicating a strong stemness within the microtissue. Of note, the h-VM significantly boosted the myogenic differentiation of MuSCs through paracrine signaling. Transplantation of the h-VM into the volumetric muscle defect not only facilitated early vessel integration with the host vasculature but also maintained muscle structural stability and provided sustained mechanical support to the defect site. Mechanistically, the h-VM effectively induced MuSCs differentiation and myofiber formation, and M2 macrophage polarization, thereby mitigating muscle fibrosis and atrophy post-injury, ultimately achieving structural and functional angio-myogenesis. Our results highlight that the h-VM can effectively re-establish the vascular regenerative microenvironment, which presents an innovative therapeutic approach to promote functional skeletal muscle regeneration following volumetric muscle loss.

One of the long-standing challenges in the field of tissue repair and regeneration is the rapid establishment of local microvascular circulation and restoration of perfusion at the site of defects or injuries. Recently, adipose tissue-derived microvascular fragments (ad-MVFs) have attracted increasing attention from researchers. Adipose tissue is rich in blood vessels, and significant progress has been made in the extraction and preservation techniques for microvascular fragments within it. Ad-MVFs promote tissue and organ repair and regeneration through three main mechanisms. First, they accelerate rapid and efficient vascularization at the injury site, enabling early vessel perfusion. Second, the stem cell components within ad-MVFs provide a rich source of cells for tissue and organ regeneration. Third, they play a role in immune regulation, facilitating integration with host tissues after implantation. The application methods of ad-MVFs are diverse. They can be directly implanted or pre-cultivated, facilitating their combination with various scaffolds and broadening their application scope. These properties have led to the wide use of ad-MVFs in tissue engineering, with promising prospects. This review demonstrates that ad-MVFs can serve as a reliable and highly feasible unit for tissue regeneration.

Regeneration of the dentin-pulp complex is essential for the lifelong structural integrity and biological function of damaged teeth. However, the inherent heterogeneity of dental stem cells limits our understanding of lineage-specific subsets critical for efficient odontogenesis and regenerative outcomes. Here, we identify a distinct subpopulation of human dental papilla cells (hDPCs) marked by CD24 expression. CD24+ hDPCs exhibit robust odontogenic differentiation capacity, preferential localization in odontoblast-generating regions during tooth development, and accumulation beneath reparative dentin in carious teeth. Functionally, CD24+ hDPCs drive coordinated regeneration of well-vascularized pulp and structurally integrated dentin tissues in both ectopic murine and preclinical in situ minipig models, significantly outperforming conventional dental pulp stem cells. Mechanistically, we delineate a BMP2-driven metabolic axis where elevated BMP signaling sustains SIRT1 expression and promotes mitochondrial metabolism. Inhibition of BMP signaling disrupts this axis, resulting in WNT signaling activation, reduced SIRT1 expression, compromised antioxidant and autophagic responses, and consequently diminished odontogenic capacity. Furthermore, BMP signaling in CD24+ hDPCs induces VEGF expression, which enhances endothelial cell recruitment and neovascularization via paracrine effects. CD24 is also a downstream marker of odontogenic BMP signaling, reflecting BMP pathway activation and correlating with odontogenic potential, though it does not directly mediate differentiation. Together, our findings characterize CD24+ hDPCs as a regeneration-competent subpopulation that integrates mitochondrial metabolism and signaling crosstalk to enable coordinated dentin and pulp regeneration, representing a translationally relevant cell source for dental tissue engineering.

Rationale: Mesenchymal stromal cells (MSCs) are considered a promising resource for cell therapy, exhibiting efficacy in ameliorating diverse bone diseases. However, most MSCs undergo apoptosis shortly after transplantation and produce apoptotic extracellular vesicles (ApoEVs). This study aims to clarify the potential role of ApoEVs from apoptotic MSCs in ameliorating osteoporosis and molecular mechanism. Methods: In this study, Dio-labeled bone marrow mesenchymal stem cells (BMSCs) were injected into mice to track BMSCs apoptosis and ApoEVs production. ApoEVs were isolated from BMSCs after inducing apoptosis, the morphology, size distribution, marker proteins expression of ApoEVs were characterized. Protein mass spectrometry analysis revealed functional differences in proteins between ApoEVs and BMSCs. BMSCs were adopted to test the cellular response to ApoEVs. Ovariectomy mice were used to further compare the ability of ApoEVs in promoting bone formation. SiRNA and lentivirus were used for gain and loss-of-function assay. Results: The results showed that BMSCs underwent apoptosis within 2 days after being injected into mice and produce a substantial quantity of ApoEVs. Proteomic analysis revealed that ApoEVs carried a diverse functional array of proteins, and easily traversed the circulation to reach the bone. After being phagocytized by endogenous BMSCs, ApoEVs efficiently promoted the proliferation, migration, and osteogenic differentiation of BMSCs. In an osteoporosis mouse model, treatment of ApoEVs alleviated bone loss and promoted bone formation. Mechanistically, ApoEVs carried Ras protein and activated the Ras/Raf1/Mek/Erk pathway to promote osteogenesis and bone formation in vitro and in vivo. Conclusion: Given that BMSC-derived ApoEVs are high-yield and easily obtained, our data underscore the substantive role of ApoEVs from dying BMSCs to treat bone loss, presenting broad implications for cell-free therapeutic modalities.

Cellular senescence is an important risk factor in the development of hepatic steatosis. Senolytics present therapeutic effects on age-related hepatic steatosis without eliminating senescent hepatocytes directly. Therefore, it highlights the need to find senolytics’ therapeutic targets. Dysfunction of adipose tissue underlies the critical pathogenesis of lipotoxicity in the liver. However, the correlation between adipose tissue and hepatic steatosis during aging and its underlying molecular mechanism remains poorly understood. We explored the correlation between white adipose tissue (WAT) and the liver during aging and evaluated the effect of lipolysis of aged WAT on hepatic steatosis and hepatocyte senescence. We screened out the ideal senolytics for WAT and developed a WAT-targeted delivery system for senotherapy. We assessed senescence and lipolysis of WAT and hepatic lipid accumulation after treatment. The results displayed that aging accelerated cellular senescence and facilitated lipolysis of WAT. Free fatty acids (FFAs) generated by WAT during aging enhanced hepatic steatosis and induced hepatocyte senescence. The combined usage of dasatinib and quercetin was screened out as the ideal senolytics to eliminate senescent cells in WAT. To minimize non-specific distribution and enhance the effectiveness of senolytics, liposomes decorated with WAT affinity peptide P3 were constructed for senotherapy in vivo. In vivo study, WAT-targeted treatment eliminated senescent cells in WAT and reduced lipolysis, resulting in the alleviation of hepatic lipid accumulation and hepatocyte senescence when compared to non-targeted treatment, providing a novel tissue-targeted, effective and safe senotherapy for age-related hepatic steatosis.

INTRODUCTION:This study aimed to assess state-trait anxiety level changes in Chinese patients with dentofacial discrepancies before and after orthognathic surgery and to explore the feasibility of developing a reference index for the preoperative screening of postoperative patients with high anxiety.METHODS:A total of 96 Chinese patients with dentofacial discrepancies who underwent orthognathic surgery were included in this study. Data were collected before orthognathic surgery and at 2 weeks (T2), 3 months, and 6 months (T4) after surgery using the State-Trait Anxiety Inventory. Receiver operating characteristic and linear regression analyses were performed to screen for preoperative indicators of postoperative high-state anxiety.RESULTS:State-trait anxiety levels in patients with dentofacial discrepancies decreased after surgery (F = 18.95, P <0.01; F = 6.90, P <0.01). Trait Anxiety Inventory can be used to screen patients with high-state anxiety from T2 to T4 (area under cover 95% confidence interval: T2, 0.74 [0.62-0.86]; 3 months, 0.79 [0.69-0.90]; T4, 0.77 [0.66-0.87], P <0.01), corresponding to cutoff values of 48.5, 46.5, and 45.5, respectively.CONCLUSIONS:All participants' state-trait anxiety levels improved after surgery compared with their preoperative levels. Preoperative trait anxiety levels can be used as a reference indicator to screen patients who may have high-state anxiety levels after orthognathic surgery. The creation of a screening scale will assist health care professionals to more pertinently help patients with high anxiety.

Background:Diabetic chronic wounds present a formidable challenge in clinical management, lacking effective treatment options. Mesenchymal stem cell (MSC) transplantation has emerged as a promising therapy for tissue repair and regeneration. However, transplanted MSCs often undergo rapid apoptosis, giving rise to heterogeneous extracellular vesicles (EVs), including apoptotic bodies (apoBDs) and apoptotic small extracellular vesicles (apoSEVs). The potential stimulatory role of these EVs in diabetic wound healing remains unknown.Methods:In this study, we investigated the effects of apoSEVs derived from adipose-derived mesenchymal/stromal cells (ADSCs) on the recovery of diabetic wounds by modulating the function of versatile target cells. First, we characterized the apoSEVs and apoBDs derived from apoptotic ADSCs. Subsequently, we evaluated the effects of apoSEVs and apoBDs on macrophages, endothelial cells, and fibroblasts, three essential cell types in wound healing, under high-glucose conditions. Furthermore, we developed a gelatin methacryloyl (GelMA) hydrogel for the sustained release of apoSEVs and investigated its therapeutic effects on wound healing in type 2 diabetic mice in vivo.Results:apoSEVs facilitated the polarization of M1 phenotype macrophages to M2 phenotype, promoted proliferation, migration, and tube formation of endothelial cells, and enhanced fibroblast proliferation and migration. However, apoBDs failed to improve the function of endothelial cells and fibroblasts. In vivo, the apoSEVs-loaded GelMA effectively promoted wound healing by facilitating collagen fiber deposition, angiogenesis, and immune regulation.Conclusion:Our study elucidates the beneficial effects of apoSEVs on wound recovery in diabetes and introduces a novel strategy for diabetic wound treatment based on apoSEVs.

Objectives: Regenerating the periodontium poses a critical challenge in oral medicine. To repair various periodontal defects, it is necessary to adopt a bio-scaffold that provides both the architecture and bioactive cues for local stem cells to migrate, reside, proliferate, and differentiate. The objective of this study is to combine a cellspecific decellularized extracellular matrix (ECM) and a biomimetic electrospinning scaffold to regenerate severely destructed periodontium.Methods: SEM, water contact angle (WCA), live/dead staining, swelling ratio, tensile test and immune-fluorescent staining were used to define the suitable topography for certain dental stem cells seeding and culturing. Transwell assay, CCK-8, Alizarin Red staining and PCR immune-fluorescent staining were used to determine ideal cell-specific ECM for PDLSCs/BMSCs migration, viability, and oriented differentiation. A biodegradable triplelayered electrospun scaffold (TLS) was fabricated by electrospinning with aligned fibers on both surfaces and a polyporous structure in the middle. The morphology and inter-porous structure of the TLS were characterized by SEM and mercury intrusion porosimetry (MIP). The surface of the TLS was functionalized with cell-specific ECM (Bi-ECM-TLS) through decellularization of the cell sheets cultured on the scaffold. The regenerative outcome of Bi-ECM-TLS was assessed by an in-situ rat periodontal defect model. Micro-CT, HE-staining, Masson's trichome staining, Sirius Red staining and Immunofluorescent staining were used for histological analysis. Results: Aligned Gelatin/PCL fibrous membrane (GPA) was most effective for both PDLSCs and BMSCs in culture with WCA around 50 degrees and better mechanical strength than the rest. MSCs favored the same type of ECM (cell-specific ECM), and their regenerative properties were effectively induced with better chemotaxis, proliferative and differentiating behaviors. TLS characterization showed that TLS possessed aligned-random-aligned structure and inter-porous structure. In a rat model of periodontal defects, the TLS functionalized by BMSCspecific ECM for bone regeneration and PDLSC-specific ECM demonstrated highest BV/TV ratio, best bone structure and ligament fiber orientation and blood vessel formation, suggesting optimal performance in regenerating both alveolar bone and periodontal ligaments over TLS, single-ECM loaded TLS and r-Bi-ECM-TLS.Significance: This study highlights the importance of combining a cell-specific decellularized ECM and a biomimetic electrospinning scaffold for targeted periodontal tissue regeneration, with potential implications for periodontal tissue engineering and improved patient outcomes.

Osteoporosis is a highly prevalent skeletal bone disorder worldwide with characteristics of reduced bone mass and increased risk of osteoporotic fractures. It has been predicted to become a global challenge with the aging of the world population. However, the current therapy based on antiresorptive drugs and anabolic drugs has unwanted side effects. Although cell-based treatments have shown therapeutic ef-fects for osteoporosis, there are still some limitations inhibiting the process of clinical application. In the present study, we developed EVs derived from skeletal muscle tissues (Mu-EVs) as a cell-free therapy to treat disuse-induced osteoporosis. Our results showed that Mu-EVs could be prepared easily and abun-dantly from skeletal muscle tissues, and that these Mu-EVs had typical features of extracellular vesicles. In vitro studies demonstrated that Mu-EVs from normal skeletal muscles could be phagocytized by bone marrow stromal/stem cells (BMSCs) and osteoclasts (OCs), and promoted osteogenic differentiation of BM-SCs while inhibited OCs formation. Correspondingly, Mu-EVs from atrophic skeletal muscles attenuated the osteogenesis of BMSCs and strengthened the osteoclastogenesis of monocytes. In vivo experiments revealed that Mu-EVs could efficiently reverse disuse-induced osteoporosis by enhancing bone formation and suppressing bone resorption. Collectively, our results suggest that Mu-EVs may be a potential cell -free therapy for osteoporosis treatment.Statement of significanceOsteoporosis is a highly prevalent skeletal bone disorder worldwide and has become a global health concern with the aging of the world population. The current treatment for osteoporosis has unwanted side effects. Extracellular veiscles (EVs) from various cell sources are a promising candidate for osteoporo-sis treatment. In the present study, our team established protocols to isolate EVs from culture supernatant of skeletal muscles (Mu-EVs). Uptake of Mu-EVs by BMSCs and osteoclasts influences the balance of bone remodeling via promoting the osteogenic differentiation of BMSCs and inhibiting the osteoclasts forma-tion of monocytes. In addition, exogenous Mu-EVs from normal skeletal muscles are proved to reverse the disuse-induced osteoporosis. We provide experimental evidence that Mu-EVs therapy is a potential cell-free platform for osteoporosis treatment towards clinical application.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Systemic elimination of senescent cells using senolytic drugs presents therapeutic effects on age-related diseases, including senile osteoporosis. However, low bioavailability and potential side effects of senolytics restrict clinical application. Therefore, we developed a bone-targeted delivery system for senolytics to effective treatment of senile osteoporosis. In this study, quercetin was screened out as the ideal senolytics for eliminating senescent BMSCs. Treatment of quercetin efficiently decreased the senescence markers in senescent BMSCs models. After treatment with quercetin in vitro, cell mitosis and calcification staining assay confirmed that the proliferation and osteogenesis of the senescent BMSCs populations were enhanced. To enhance the effectiveness and minimize the side effect of treatment, liposomes decorated with bone affinity peptide (DSS)6 were constructed for bone-targeted delivery of quercetin. After administration of liposomes loading quercetin in two aged mice models, histological and cellular analysis confirmed that bone-targeted treatment with quercetin efficiently eliminated senescent cells in bone, restored the function of BMCSs, and promoted bone formation in aged mice models when compared to non-targeted treatment. Taken together, the bone-targeted delivery of senolytics efficiently eliminates senescent cells to recover bone mass and microarchitecture, showing an effective treatment for senile osteoporosis. STATEMENT OF SIGNIFICANCE: Senile osteoporosis, a common and hazardous chronic disease, has been still lacking effective therapy. How to effectively eliminate the hazards of senescent cells in skeleton to bone formation remains challenge. In this study, quercetin was screened out as the ideal senolytic drug for senescent BMSCs and could effectively eliminated senescent BMSCs to restore the cellular functions of senescent BMSCs models in vitro. Then, the bone-targeted liposomes were designed to encapsulate and deliver senolytics efficiently to senile bone tissue. Based on two aged mice models, we confirmed that bone-targeted delivery of quercetin efficiently eliminated senescent cells in skeleton and enhanced bone formation in vivo, suggesting the bone-targeted elimination of senescent cells is an effective treatment for senile osteoporosis.

Pulp loss is accompanied by the functional impairment of defense, sensory, and nutrition supply. The approach based on endogenous stem cells is a potential strategy for pulp regeneration. However, endogenous stem cell sources, exogenous regenerative signals, and neovascularization are major difficulties for pulp regeneration based on endogenous stem cells. Therefore,the purpose of our research is to seek an effective cytokines delivery strategy and bioactive materials to reestablish an ideal regenerative microenvironment for pulp regeneration. In in vitro study, we investigated the effects of Wnt3a, transforming growth factor-beta 1, and bone morphogenetic protein 7（BMP7） on human dental pulp stem cells（h-DPSCs） and human umbilical vein endothelial cells. 2D and 3D culture systems based on collagen gel, matrigel, and gelatin methacryloyl were fabricated to evaluate the morphology and viability of h-DPSCs. In in vivo study, an ectopic nude mouse model and an in situ beagle dog model were established to investigate the possibility of pulp regeneration by implanting collagen gel loading BMP7. We concluded that BMP7promoted the migration and odontogenic differentiation of h-DPSCs and vessel formation. Collagen gel maintained the cell adhesion, cell spreading, and cell viability of h-DPSCs in 2D or 3D culture. The transplantation of collagen gel loading BMP7 induced vascularized pulp-like tissue regeneration in vivo. The injectable approach based on collagen gel loading BMP7 might exert promising therapeutic application in endogenous pulp regeneration.