Journal of Tissue Engineering and Regenerative Medicine最新文献

The pancreatic extracellular matrix (ECM) is an enormously complex construct. Previous studies underline the challenges to identify the optimal combinations and ratios of individual ECM proteins for promoting survival and function of isolated and transplanted islets. This study aimed on assessing the efficiency of solubilized natural ECM extracted from juvenile pigs, an unlimited donor source. Isolated human islets were cultured under a hypoxic atmosphere (2% oxygen) in media supplemented with either solubilized porcine pancreatic ECM (ppECM) or a mixture of human ECM proteins composed of collagen-IV, laminin-521, and nidogen-1 (hEPM). Control islets were cultured under identical conditions without ECM-compounds. Reactive oxygen species production increased three-fold in controls but was reduced by hEPM or ppECM. Early apoptosis remained on preculture levels when islets were treated with hEPM or ppECM. Preculture viability was preserved when hEPM or ppECM was administered. Whilst controls failed to respond to glucose challenge, treatment with hEPM or ppECM preserved the physiological insulin response. In summary, overall survival was significantly highest in ppECM-treated islets. This study presents a new approach to protect human islets from hypoxia-induced damage by supplementing media with ppECM extracted from an unlimited donor source. The findings may also serve as starting point for a novel encapsulation technique to protect isolated human islets.

Odontogenic stem cells are mesenchymal stem cells (MSCs) with multipotential differentiation potential from different dental tissues. Their osteogenic differentiation is of great significance in bone tissue engineering. In recent years, it has been found that long noncoding RNAs (lncRNAs) participate in regulating the osteoblastic differentiation of stem cells at the epigenetic level, transcriptional level, and posttranscriptional level. We reviewed the existing lncRNA related to the osteogenic differentiation of odontogenic stem cells and emphasized the critical mechanism of lncRNA in the osteogenic differentiation of odontogenic stem cells. These findings are expected to be an important target for promoting osteoblastic differentiation of odontogenic stem cells in bone regeneration therapy with lncRNA.

Healthy skeletal muscle can regenerate after ischaemic, mechanical, or toxin-induced injury, but ageing impairs that regeneration potential. This has been largely attributed to dysfunctional satellite cells and reduced myogenic capacity. Understanding which signalling pathways are associated with reduced myogenesis and impaired muscle regeneration can provide valuable information about the mechanisms driving muscle ageing and prompt the development of new therapies. To investigate this, we developed a high-throughput in vitro model to assess muscle regeneration in chemically injured C2C12 and human myotube-derived young and aged myoblast cultures. We observed a reduced regeneration capacity of aged cells, as indicated by an attenuated recovery towards preinjury myotube size and myogenic fusion index at the end of the regeneration period, in comparison with younger muscle cells that were fully recovered. RNA-sequencing data showed significant enrichment of KEGG signalling pathways, PI3K-Akt, and downregulation of GO processes associated with muscle development, differentiation, and contraction in aged but not in young muscle cells. Data presented here suggest that repair in response to in vitro injury is impaired in aged vs. young muscle cells. Our study establishes a framework that enables further understanding of the factors underlying impaired muscle regeneration in older age.

Numerous patients experience articular cartilage defects (ACDs), which are characterized by progressive cartilage degradation and often lead to osteoarthritis (OA). Consequently, 44.7% of OA patients suffer from dyskinesia or disability. Current clinical drug treatments offer limited effectiveness in fully curing the disease. In this study, we propose a collaborative approach that combines physical and biological cues to promote cartilage regeneration. A biodegradable piezoelectric poly (l-lactic acid) (PLLA) nanofiber scaffold facilitates in situ, battery-free electrical stimulation under natural joint loading, while extracellular vesicles (EVs) serve as communication mediators between cells and promote cell proliferation, migration, and secretion of type II collagen. In this combined approach, EVs attached to PLLA are gradually released by localized piezoelectric electrical stimulation and taken up by chondrocytes. This process results in the organization of type II collagen along the PLLA fiber surface, ultimately forming cartilage lacunae that facilitate the residence of new chondrocytes. As an outcome, a significant round cartilage defect (diameter: 3 mm and depth: 1 mm) in the PLLA/EVs group (rat and knee) was rapidly restored within six weeks. In contrast, individual EVs and PLLA groups demonstrated considerably weaker cartilage regeneration capabilities. This research suggests that the synergistic effect of electromechanical stimulation and EVs-based biological cues is a crucial intervention method for treating OA.

To construct tissue-engineered blood vessels (TEBVs) in vitro, it is necessary to transfer seed cells to three-dimensional (3D) scaffolds for culture. However, what happens to the behavior of the cells after they are transferred to the scaffold is unclear. Therefore, in this study, a transcriptome analysis was used to characterize the differentially expressed genes (DEGs) of vascular smooth muscle cells (VSMCs) before and after transfer to 3D polyglycolic acid (PGA) scaffolds and to understand the changes in functional gene expression in the early stage of 3D culture. Transcriptome sequencing results showed that DEGs in the seed cells were mainly enriched in cell proliferation and cell-cell adhesion. The DEGs of cells grown in a 3D PGA scaffold (PGA-VSMCs) were mainly enriched in signal transduction. Furthermore, we found that ERK1/2 was significantly activated in PGA-VSMCs and inhibiting the phosphorylation level of ERK 1/2 in PGA-VSMCs significantly increased the expression of elastin. In conclusion, the PGA scaffold material altered gene expression in VSMCs and affected the elastin production. This study advances our understanding of biomaterial-cell interactions and provides valuable insights for improving the cultivation of TEBVs.

Oral and maxillofacial bone defect repair in patients remains challenging in clinical treatment due to the different morphologies of bone defects. An injectable hydrogel of microspheres with sustained bone morphogenetic protein 9 (BMP9) expression for oral and maxillofacial bone defect repair has been developed. This study is bioinspired by the substantial osteogenesis property of recombinant adenoviruses expressing bone morphogenetic protein 9 (Ad-BMP9) and minimally invasive treatment by injection. A novel scaffold encompassing bone mesenchymal stem cells (BMSCs) transfected with Ad-BMP9 was produced and cocultured on a superficial surface of monodisperse photocrosslinked methacrylate gelatin hydrogel microspheres (GelMA/MS, produced with microfluidic technology). The biological tests including live/dead cell staining, phalloidin staining, cell counting kit-8 (CCK-8) assay, alkaline phosphatase (ALP) activity and staining, alizarin red S staining, and quantitative real-time polymerase chain reaction (RT-qPCR), revealed that the hydrogel microspheres exhibited good biocompatibility and remarkably promoted the osteogenic differentiation of BMSCs in vitro. In addition, a small needle was injected the innovative scaffold beneath the nude mice’s skin. The micro-CT and histological staining assay results demonstrated that the new implant, with high blood vessel formation markers (CD31-positive cells) expression over four and eight weeks, achieved significant vascularized bone-like tissue formation. Consequently, the injectable hydrogel microspheres, cocultured with BMSC transfected with Ad-BMP9, enhanced vascularized bone regeneration, therefore representing a facile and promising technique for the minimally invasive treatment of oral and maxillofacial bone defects.

Distraction osteogenesis (DO) is a widely employed method for the treatment of limb discrepancies and deformity correction. This study aimed at observing the histomorphological and ultrastructural changes of peripheral nerves around the distraction area during DO and investigating the self-repair mechanism of peripheral nerves in a rat DO model. Sixty rats underwent right femoral DO surgery and were randomly separated into six groups: Control (latency, no distraction, n = 10), Group 0-week (after distraction, n = 10), Group 2-week (n = 10), Group 4-week (n = 10), Group 6-week (n = 10), and Group 8-week (n = 10) at consolidation phase. The right femur of rats in Group 0-week, Group 2-week, Group 4-week, Group 6-week, and Group 8-week was subjected to continuous osteogenesis distraction at a rate of 0.5 mm/day for 10 days. Motor nerve conduction velocity (MNCV) of the sciatic nerve, sciatic function index (SFI), histological analyses, and transmission electron microscopy were conducted to evaluate nerve function. The MNCV and SFI of Group 0-week, Group 2-week, Group 4-week, and Group 6-week were significantly lower than the Control (P < 0.05). No statistical differences were found between the Control and Group 8-week in terms of MNCV and SFI (P > 0.05). Injuries to nerve fibres and nodes of Ranvier were observed in the Group 0-week, whereas the nerve fibres returned to the normal arrangement in the Group 8-week and oedema of myelin disappeared, with the continuity of axons and lamellar structure of myelin being restored. Femoral DO in rats with a rate of 0.5 mm/day may cause sciatic neurapraxia, which can be self-repaired after 8 weeks of consolidation. The paraneurium around the sciatic nerve enables it to glide during the distraction phase to reduce the occurrence of injurious changes.

Background. Insufficient bone formation is the key reason for the imbalance of bone metabolism and one of the main mechanisms for the occurrence and deterioration of postmenopausal osteoporosis (PMOP). Accumulating evidence has demonstrated that pulsed electromagnetic field (PEMF), as a physiotherapy, can treat osteoporosis by promoting osteogenic differentiation in osteoblasts. However, little is known about its mechanisms. Methods. In vivo, ovariectomized mice were administered PEMF for 4 weeks, and skeletal analysis was conducted. In vitro, hydrogen peroxide-treated mouse osteoblast precursor cells with or without PEMF intervention were subjected to osteogenic differentiation testing and miRNA microarrays. The potential target miRNAs were validated, followed by gene expression assays to further clarify their regulatory relationships with target pathways. Results. We found that PEMF reduced bone loss in ovariectomized mice and promoted osteogenic differentiation of hydrogen peroxide-treated osteoblast precursor cells via downregulation of miR-6976-5p. Mechanistically, reduced miR-6976-5p enhanced the nuclear transport of phosphorylated Smad1/5/9 by upregulating Smad4, thereby activating the BMP/Smad pathway. Additionally, the administration of miR-6976-5p inhibitors successfully promoted osteogenic differentiation in vitro, and its antagomirs protected bone mass in vivo. miR-6976-5p mimics and agomirs acted in the opposite way. Conclusion. These results provide evidence that PEMF alleviates estrogen deficiency-induced bone loss by activating osteoblastic progenitor cells and maintaining their osteogenic differentiation and shed light on the mechanisms involved, which may provide a potential option for the clinical application of PEMF in PMOP.

Nonsyndromic microtia is a kind of congenital ear malformation with unclear pathogenic genes. Cadherin-11 (CDH11, OB-cadherin) is a member of the cadherin family, which has been demonstrated to play important roles in controlling morphogenesis and cell biological characteristics during multiple developmental processes. In the present study, we found low expression of CDH11 in microtia cartilage compared with the normal one for the first time. For a more comprehensive and in-depth understanding of CDH11 in microtia development, we performed both gain- and loss-of-function experiments to detect the effect of CDH11 on chondrocytes. CDH11 promoted chondrocyte proliferation by increasing S-phase cell numbers and increasing cell migration, which is important for tissue morphogenesis. Additionally, knockdown of CDH11 in chondrocytes reduced the quality of engineered cartilage by decreasing the key transcription factors of chondrogenesis, SOX9 expression, and cartilage ECM production, including collagen type II (COL2A) and elastin (ELN), compared to the control group. Furthermore, RNA-Seq on CDH11 knockdown chondrocytes showed that it was highly related to HOX family genes, which have been reported to be important regulatory genes patterning craniofacial tissue formation. This study identified CDH11 as a candidate pathogenic gene of microtia and supported the potential key role of CDH11 in craniofacial malformations.

Treatment options for critically sized bone defects are currently limited to metal osteosynthesis, autologous bone grafting, or calcium-based implants to bridge the gap. Additive manufacturing techniques pose a possible alternative. The light-basedthree-dimensional printing process of vat photopolymerization (VP) is of particular interest since it enables the printing of complex scaffold architectures at high resolution. This review compares multiple vat photopolymerization processes as well as the employed resin components’ interactions with musculoskeletal cells and tissue. The results show an outstanding printing capability, exceeding the potential of other printing methods. However, despite the availability of various biocompatible materials, neither the mechanical strength of bone nor the scale necessary for clinical application has been achieved so far when relying on single material constructs. One possible solution is the development of adaptive hybrid constructs produced with multimaterial VP.