Tissue engineering and regenerative medicine最新文献

Background: The renal glomerulus, a capillary network between two arterioles, is essential for urine production in mammals. While it partially regenerates after renal injury, its precise mechanisms remain unclear, and stereological studies on post-injury glomerular structural changes are limited.

Methods: Therefore, this study aims to investigate three-dimensional glomerular alterations over time following ischemia-reperfusion injury (IRI) in adult mouse kidneys. Synchrotron radiation micro-computed tomography (SR-MCT) and immunohistochemical analyses were employed to visualize and quantify three-dimensional glomerular structures and nephron numbers from 1 to 21 days post-IRI.

Results: A unique "twin glomeruli" structure, linked to three arterioles through an atypical "aefferent" arteriole, appeared between 3 and 21 days post-IRI, peaked on day 9, and exhibited features distinct from both degenerating and developing glomeruli. SR-MCT revealed a time-dependent increase in nephron numbers between 1 and 21 days post-IRI, while immunohistochemistry revealed significant elevated glomerular and tubular densities from days 9 to 21. These findings suggest that twin glomeruli are transient structures induced by IRI and may contribute to nephron expansion.

Conclusion: This study challenges current understanding by demonstrating that twin glomeruli represent an atypical glomerular structure occurring during kidney repair and suggesting possible neonephrogenesis in the adult mouse kidney, a phenomenon previously considered impossible after birth. If similar results are observed in humans, it could lead to significant changes in the approaches and objectives for treating renal diseases. Additionally, a comprehensive investigation into the numerical response of glomerular counts to various stimuli could provide valuable insights into kidney regeneration and repair.

Background: Electric field (EF) stimulation is an emerging biophysical approach that enhances stem cell function by mimicking endogenous wound currents. However, its effects on tonsil-derived mesenchymal stem cells (TMSCs) remain poorly understood.

Methods: A low-intensity EF stimulation system (0-12 mV; potential difference between parallel electrodes, 5 mm apart; 5 min on/5 s off for 38 h) was established to examine the effects of EF on TMSC viability, proliferation, stemness, and chondrogenic differentiation. Young and senescent TMSCs were evaluated for metabolic activity, cell cycle distribution, and expression of stemness- and chondrogenesis-related markers. For differentiation assays, cells were preconditioned with EF stimulation before chondrogenic induction.

Results: Moderate EF intensities (4-8 mV) enhanced the viability, metabolic activity, and proliferation of both young and senescent TMSCs, whereas excessive stimulation (12 mV) reduced these functions without causing cell death. In senescent TMSCs, EF stimulation promoted S-phase entry and upregulated Cyclin A2 and Cyclin B1 expression, suggesting partial restoration of proliferative potential. In young TMSCs, EF stimulation increased NANOG, OCT4, and SOX2 expression, thereby supporting stemness maintenance. EF stimulation enhanced glycosaminoglycan deposition and chondrogenic marker expression (Aggrecan, COL2A1, and SOX9) when applied before chondrogenic induction but exerted an inhibitory effect when applied during the differentiation phase.

Conclusion: Low-intensity EF stimulation serves as a tunable bioelectric cue that enhances the proliferation, stemness, and early chondrogenic potential of TMSCs in an intensity- and state-dependent manner, providing a non-invasive strategy to improve mesenchymal stem cell function for regenerative applications.

Background: The perichondrium-a natural fibrous membrane encasing cartilage-plays a pivotal role in nutrient delivery and matrix regulation; however, it is often overlooked in engineered constructs. This study aimed to fabricate a perichondrium-mimicking three-dimensional (3D) bioprinted auricular cartilage construct utilizing a hybrid bioink and to assess the effects of adipose-derived stem cell (ADSC) outer layers on cartilage matrix formation, vascularization, and construct stability.

Methods: Chondrocyte spheroids and ADSCs were isolated from New Zealand white rabbits and embedded in bioinks composed of either alginate alone or alginate/GelMA composites. A dual-mode printing strategy facilitated the fabrication of constructs with 3 and 10 layers. ADSCs were printed as outer "perichondrium-mimicking" layers in designated groups (G2, G4, and G6). Constructs were implanted subcutaneously in nude mice for 6 weeks. Histological analyses, immunohistochemical assessments (CD31), and image-based quantitative analyses were conducted.

Results: The inclusion of ADSC layers significantly enhanced cartilage matrix synthesis and decreased calcification, particularly in constructs containing GelMA. Group G4 exhibited the highest levels of glycosaminoglycan and collagen content, as well as the lowest calcium deposition. Ten-layer constructs (G6) preserved structural integrity and supported neovascularization; however, the final cartilage thickness did not proportionally scale with the initial print height.

Conclusion: The incorporation of ADSC-laden perichondrium-mimicking layers in conjunction with a hybrid alginate/GelMA bioink synergistically enhances cartilage formation, matrix quality, and vascular integration in large constructs. This biomimetic approach is a promising platform for developing clinically relevant cartilage grafts for auricular reconstruction and other cartilage repair applications.

Background: Conventional drug-eluting stents suppress neointimal hyperplasia but delay re-endothelialization, raising long-term safety concerns. This study developed and evaluated a sirolimus-WKYMVm eluting stent (S-WES) to simultaneously promote re-endothelialization and suppress neointimal hyperplasia.

Methods: Sirolimus-eluting stents (SES), WKYMVm-eluting stents (WES), and S-WES were fabricated using electrospray. Surface morphology was characterized via scanning electron microscopy (SEM), and in vitro drug-release kinetics were determined using high-performance liquid chromatography. Biological efficacy was assessed using human umbilical vein endothelial cell (HUVEC) and smooth muscle cell (SMC) assays. In vivo performance was evaluated over 4 weeks, followed by optical coherence tomography (OCT) and histopathological analysis.

Results: SEM analysis showed that S-WES had a uniform, crack-free polymer coating. Each stent was consistently loaded with sirolimus (105.15 ± 25.54 μg) and WKYMVm (1.07 ± 0.18 μg), yielding a dual drug-release profile. WKYMVm was almost completely released within 7 days, whereas sirolimus showed sustained release (day 1: 22.43 ± 5.32%, day 28: 94.38 ± 4.11%). In vitro assays showed that sirolimus suppressed SMC migration and HUVEC proliferation, while WKYMVm significantly enhanced HUVEC proliferation. In vivo OCT revealed reduced neointimal hyperplasia in the S-WES group (29.64 ± 8.66 μm²) compared with SES (34.65 ± 7.50 μm²; p = 0.041). Histopathology and immunohistology showed reduced stenosis ratio (28.39 ± 6.84%), decreased α-SMA expression, and increased VE-cadherin, CD31-positive endothelial coverage in the S-WES group.

Conclusion: The sirolimus-WKYMVm dual-drug stent enhances re-endothelialization and inhibits neointimal hyperplasia, thereby offering a promising strategy for improving the efficacy and long-term safety of cardiovascular stents.

Background: Growing evidence validates the vital function of mesenchymal stem cells (MSCs) in tumor development. Our previous findings have illustrated the role of MSCs in the invasion and recurrence of ameloblastoma. Stem cells can be transplanted to release paracrine factors in the tumor microenvironment (TME) to inhibit tumor progression and recurrence. The paracrine function of human amniotic mesenchymal stromal cells (HAMSCs) benefits bone regeneration. However, the dual function of HAMSCs in inhibiting tumor progression and promoting bone regeneration in the TME remains unknown.

Methods: To analyze the role of HAMSCS in the cross-talk between mesenchymal ameloblastoma-derived cells (M-AMCs), human bone marrow mesenchymal stem cells (HBMSCs), and HAMSCs, an in vitro co-culture system of M-AMCs, HBMSCS, and HAMSCS was prepared. An in vivo ectopic transplantation model was employed further to detect the therapeutic effect of HAMSCs on bone regeneration.

Results: A high-level basal autophagy was detected in the stroma of ameloblastoma. In the in vitro co-culture models, M-AMCs suppressed the proliferation, differentiation, migration, and autophagy of HBMSCs, and conversely, HBMSCs promoted the above phenotypes of M-AMCs. HAMSCs promoted the proliferation, differentiation, migration and autophagy of the co-cultured HBMSCs. Additionally, HAMSCs mediated the cross-talk between M-AMCs and HBMSCs. The in vivo ectopic transplantation model indicated that transplanted HAMSCs promoted bone regeneration by inhibiting the growth of M-AMCs and enhancing autophagy, as well as osteogenesis in bone defects of mice.

Conclusions: The interaction of M-AMCs and HBMSCs may be associated with ameloblastoma recurrence. HAMSCs regulate the cross-talk between M-AMCs and HBMSCs to increase the autophagic level in the TME, thus inhibiting the progression and recurrence of ameloblastoma and promoting bone regeneration. Therefore, HAMSC-based therapy provides an alternative to facilitate bone regeneration and repair of ameloblastoma-induced bone defects.

Background: Mesenchymal stem (stromal) cells are a promising cell source for regenerative medicine, but their therapeutic efficacy is often limited by poor engraftment and survival post-transplantation. One major contributing factor is anoikis, a form of apoptosis triggered by cell detachment from the extracellular matrix. Spheroid culture systems have shown potential to enhance cell survival and stemness, yet the mechanisms by which they confer resistance to anoikis remain unclear.

Methods: We established spontaneous spheroids from human umbilical cord-derived mesenchymal stem (stromal) cells (UC-MSCs) and performed RNA-sequencing analysis to compare gene expression profiles between spheroid and monolayer cultures. Differentially expressed genes were identified and subjected to GO and pathway enrichment analyses. Functional assays included the use of PI3K/Akt and HIF-1 pathway inhibitors to dissect their role in anoikis regulation. Expression levels of apoptosis-related genes were validated by qRT-PCR.

Results: Spheroid UC-MSCs exhibited significantly enhanced resistance to anoikis. Transcriptomic analysis revealed upregulation of both pro-apoptotic and anti-apoptotic genes, suggesting a balanced but regulated apoptotic threshold. Downregulation of executioner genes such as BAX, BAK1, and FADD, along with activation of PI3K/Akt and HIF-1α pathways, suggested effective suppression of apoptotic execution. Inhibitor experiments confirmed these pathways as key contributors to anoikis resistance.

Conclusion: Our findings demonstrate that spheroid formation promotes a survival-permissive gene expression profile in UC-MSCs, driven in part by PI3K/Akt and hypoxia signaling. These insights advance the understanding of spheroid-mediated anoikis resistance and may inform strategies to enhance stem cell-based therapies.

Background: The Wnt signalling pathway, one of the key classical stem cell pathways, plays an important role in helping the liver regenerate after injury. Stem cells can influence changes in adult cell behaviour by either activating or inhibiting this pathway. When liver damage is severe, the organ's ability to regenerate may be compromised, sometimes leading to structural changes. Umbilical cord-derived mesenchymal stem cells have shown promise in improving the liver microenvironment more effectively through the classical Wnt pathway.

Methods: Studies were conducted on both reviews and original experiments. This paper used a repeated-measures design, and statistical analysis was performed using a two-factor, two-level repeated-measures model to analyze the experimental results. The measurements taken before and after the intervention were compared, and interactions were examined. C57/6 BAL mice were randomly divided into two to three groups, with in vivo Choline-methionine deficiency C57 black mouse animal disease models, and hepG2 replace complex intake primary liver cell problem to mimic in vitro cell models simulated. One sample from each group was randomly selected for model validation, and stem cell injection experiments were conducted after validation. The experiments were carried out in a wholly randomized manner to explore the phenotype and intrinsic mechanisms of liver cirrhosis and steatosis.

Results: In cirrhosis, inflammatory fibrosis, endoplasmic reticulum stress, and mitochondrial damage are key virulent factors in the primary stage. After treating mice for a month and a half, the AST content in the peripheral blood plasma of animals and the expression of ALT increased. The interventional treatment of umbilical cord mesenchymal cell infusion (three times a month at doses of 10⁵, 4 × 10⁵, or 10⁶) has further contributed to understanding the underlying mechanisms. The Wnt pathway plays a significant role in organ and tissue reversing function (p < 0.05).

Conclusion: Umbilical cord mesenchymal stem cells were used to treat cirrhosis, ranging from end-stage to early stages, in methionine-deficient rats by modulating the Wnt pathway. It can inhibit the progression of steatosis-related inflammation and fibrosis, further depresses cirrhosis in mice and humans, and underscores the significance of umbilical stem cells in public health.

Background: Alzheimer's disease (AD) presents significant unmet medical needs with no effective therapeutic options. Current pharmacological treatments provide only symptomatic relief and do not prevent the ongoing neurodegeneration. Cell therapies using mesenchymal stem cells (MSCs) are being widely investigated for its potential in treating AD but remain unverified. This review aimed to evaluate therapeutic effects of MSCs on AD patients through a review of clinical trial literatures.

Methods: Publications and registered clinical trials from January 2011 to June 2025 were collected from the international databases (ClinicalTrials.gov, PubMed, Web of Science, SCOPUS) using the keywords of "Alzheimer's disease", "mesenchymal stem cells", and "clinical trials". After initial screening and sorting, 17 clinical trials and 4 related papers were finally selected for in-depth analysis.

Results: The 17 clinical trials were mostly early stages with 4 phase 1 (23.5%), 9 phases 1/2 (52.9%), 3 phase 2 (17.7%), and 1 pilot phase (5.9%). The source of MSCs included allogeneic umbilical cord blood (UCB) in 5 trials (29.4%), autologous adipose tissue in 4 (23.5%), allogeneic umbilical cord (UC) in 3 (17.6%), allogeneic bone marrow (BM) in 3 (17.6%), allogeneic placenta in 1 (5.9%) and 1 unknown (5.9%). Administration routes were primarily intravenous (IV) infusion in 12 trials (70.6%), intracerebroventricular (ICV) infusion via Ommaya reservoir in 3 (17.6%), and stereotactic brain injection (SBI) in 2 (11.8%). Among the 17 clinical trials, outcome data of 7 trials have been reported in 4 clinical papers and 1 clinical results posted in ClincalTrials.gov: 4 trials using UCB MSCs (NEUROSTEM-AD) in 2 papers, 2 trials using BM MSCs (Lomecel-B) in 2 papers and 1 trial using adipose MSCs (AstroStem) in ClinicalTrials.gov. All 5 reports using different cell types, administration routes or dosages claimed the safety of MSCs administration. As for the therapeutic efficacy, 2 reports using Lomecel-B reported meaningful improvement in AD pathophysiology or cognitive functions, while the other 3 reports using NEUROSTEM-AD or AstroStem failed to show statistically significant efficacy.

Conclusion: The analysis of 17 clinical trials and 5 relevant clinical outcomes showed that MSCs therapy if feasible and generally safe in AD patients. There are indications of potential therapeutic benefits such as improved cognitive function or quality of life measures in some AD patients. However, its therapeutic efficacy has not been proven definitely due to small size of subjects, variations in dosage, MSCs source, and administration scheme (route, timing, and frequency). Larger subject sizes and well-controlled trials are needed to provide more conclusive evidence.

Background: Type I atelocollagen is used to treat full-thickness chondral lesions. However, evidence on the concentration-dependent effects of atelocollagen-based scaffolds on chondrogenesis is lacking. This study aimed to evaluate the in vitro and in vivo chondrogenic potentials of low-, intermediate-, and high-concentration atelocollagen-based scaffolds in a rabbit model of osteochondral defects.

Methods: Human mesenchymal stem cells (hMSCs) were encapsulated in 3%, 6%, and 9% type I collagen gels to assess cell viability and chondrogenic differentiation in vitro. In vivo, full-thickness osteochondral defects (4 × 4 mm) were created in 24 rabbits and treated as follows: Group 1 (microfracture only), Group 2 (microfracture + 3% atelocollagen), Group 3 (microfracture + 6%), and Group 4 (microfracture + 9%). The animals were euthanized at 4, 8, or 12 weeks. Macroscopic and histological outcomes were evaluated using gross morphological assessment and modified O'Driscoll scores.

Results: At 8 weeks postoperatively, Group 4 (7.17 ± 0.76) exhibited significantly higher macroscopic scores than Group 2 (3.83 ± 0.29, p < 0.001) and Group 3 (4.50 ± 0.50, p < 0.001), indicating near-complete defect filling and smooth surface restoration. At 12 weeks, Groups 2 (7.33 ± 0.58), 3 (7.50 ± 0.87), and 4 (8.00 ± 0.00) all demonstrated significantly higher macroscopic scores than Group 1 (0.17 ± 0.12, p < 0.001 for all). Histologically, all atelocollagen-treated groups (Group 2:20.77 ± 1.55; Group 3:23.5 ± 1.00; Group 4:23.67 ± 1.44) exhibited significantly higher scores than Group 1 (1.67 ± 0.29, p < 0.001), with Group 4 achieving the highest overall.

Conclusion: High-concentration atelocollagen-based scaffolds significantly enhanced both the efficiency and quality of cartilage regeneration by providing mechanical support and a favorable microenvironment for chondrogenesis.

Background: Achieving stable and functional integration of synthetic implants with host tissue remains a key challenge in tissue engineering. Medpor®, a porous high-density polyethylene (HDPE) implant widely used in craniofacial reconstruction, provides excellent mechanical strength but lacks bioactivity, limiting early cell adhesion, vascularization, and extracellular matrix (ECM) deposition.

Methods: To enhance Medpor® biointegration, we employed a multi-faceted modification strategy combining plasma treatment with biologically active components. Treated implants were coated with collagen and fibrin hydrogels and further supplemented with a platelet-derived Purified Exosome Product (PEP). Modified and control implants were evaluated in a subcutaneous mouse model to assess host tissue response, vascularization, and implant integration.

Results: Tissue ingrowth was observed in the pores of all Medpor® implants. Plasma treatment significantly increased the surface hydrophilicity of Medpor®, promoting host cell adhesion and tissue infiltration. Implants modified with both hydrogels and PEP exhibited enhanced ECM deposition, greater vascular density, and improved tissue integration compared to untreated Medpor®. The combination of physicochemical surface treatment and biochemical cues led to a synergistic effect, supporting tissue ingrowth and angiogenesis under a controlled host immune response.

Conclusion: This study demonstrates that integrating plasma surface modification with bioactive hydrogels and PEP can effectively enhance the biointegration of Medpor® implants in vivo. The combined approach significantly enhances implant vascularization and ECM development, offering a promising translational strategy for improving synthetic implant performance in regenerative and reconstructive biomaterial applications.