Journal of Tissue Engineering and Regenerative Medicine最新文献

Meniscal injuries present a significant clinical challenge due to the limited self-healing capacity of avascular regions and the unsatisfactory long-term outcomes of current repair strategies. Collagen, the primary structural component of the meniscal extracellular matrix (ECM), plays a crucial role in maintaining its biomechanical integrity and guiding tissue regeneration. This review summarizes recent advances in collagen scaffolds technology, focusing on materials, collagen extraction, and scaffold fabrication methods, as well as their in vivo interactions with cells that regulate tissue regeneration. The mechanical enhancement of collagen scaffolds through crosslinking and reinforcement with synthetic polymers is discussed, alongside strategies for controlled degradation and biological integration. Despite remaining challenges in mechanical durability and long-term stability, these developments position collagen-based scaffolds as a promising avenue toward clinically viable meniscal repair solutions.

Decellularized articular cartilage of human origin presents itself as the most homologous filling material for focal cartilage defects. Yet, the full repopulation of the exceptionally dense collagen construct has never been achieved without providing host cells with artificially created migration paths into the matrix. Within this study, we examine the use of a femtosecond laser to engrave fine patterns into human articular cartilage before decellularization and GAG depletion (decell-deGAG). Scaffolds were tested for decellularization success and mechanical behavior. Seeding tests were performed to assess biocompatibility and examine the performance in a simulated defect environment using an osteochondral plug model in vitro and in vivo in an ectopic nude mouse model. The composition and structure of the newly formed repair tissue and macrophage recruitment were observed via histology. The femtosecond laser was successful in engraving deep, fine structures into the matrix without the thermal damage found with other laser techniques. Engraving was also beneficial for decellularization success. The resulting decell-deGAG scaffold featured a compressive modulus many times stronger than other biomaterials commonly used for cartilage regeneration and presents a defect filling material that is similar to the tissue it is meant to replace. Moreover, the incisions promoted the repopulation with therapeutically relevant cells. A favorable spatial environment inside the incisions facilitated the formation of repair tissue that mimics hyaline cartilage in composition and collagen orientation. Scaffolds were well-integrated within simulated defects. Femtosecond laser–engraved cartilage poses an authentic defect filling material with cartilage-like properties. When used in combination with cell seeding, it promotes the formation of differentiated repair tissue. Thus, the hereby presented biomaterial shows great potential in improving the repair of focal cartilage defects and reducing long-term graft failures.

Chronic respiratory diseases are a major global health concern. Lung epithelial dysfunction is a common underlying feature of many such conditions; hence, reconstructing the diseased epithelium with functional epithelial cells is a promising therapeutic approach. There are various endogenous stem cell and progenitor populations in the lung epithelium that can be utilized for transplantation. Additionally, pluripotent stem cells (PSCs) have emerged as a valuable source for generating therapeutic cells due to their capacity for indefinite self-renewal and the availability of directed differentiation protocols to transform them into lung progenitors or mature lung epithelial cells. This review discusses the endogenous stem cell and progenitor populations of the lung epithelium, recent advances in developing directed differentiation protocols to generate these cells, and the application of both endogenous and PSC-derived lung epithelial cells for disease modeling in vitro and as cell therapies in vivo. It provides valuable insights into the current progress of regenerative medicine within the respiratory field and highlights areas that require further research.

The dermal barrier is widely considered the body’s first line of defense against most foreign bodies, protecting it from both moisture loss and bacterial invasion. However, when the skin is ruptured for long-term medical interventions (e.g., transcutaneous prosthetics), it is difficult to restore and maintain this protective barrier. Although there are no direct, biological examples of true transcutaneous features in the human body, similar phenomena can be observed in phalangeal nails. This study aims to investigate keratin, the primary component of fingernails, in its hydrolyzed form as an additive to induce cell adhesion in two representative scaffold types. Electrospun fibers and chitosan–gelatin cryogels—two well-characterized scaffolds used in dermal tissue engineering—were selected for this study as a fibrous and macroporous foundation. Both electrospun fibers and cryogels were fabricated with a range of keratin additive concentrations (0, 1, 3, 5, 7, and 10 wt/wt% and wt/v% for electrospun fibers and cryogels, respectively) and tested for surface properties, mechanical strength, biocompatibility, and material behavior. Overall, it was determined that hydrolyzed keratin had a positive effect on cell adhesion and proliferation but that high quantities of the keratin resulted in adverse effects on the scaffold properties. With dermal applications in mind, this study found that 5 and 7 wt/wt% keratin electrospun fibers possessed required cell counts, surface energies, tensile strength, and contact angle, all with consistent reproducibility. For the cryogels, 3 and 5 wt/v% keratin had the best combined performance, maintained structural integrity through swelling and porosity, and displayed minimal loss in compressive strength. Therefore, hydrolyzed keratin represents a promising additive for bothelectrospun fibers and cryogels in tissue engineering applications.

Glycolysis supports mesenchymal stem cell (MSC) proliferation and sustains their undifferentiated state by maintaining energy supply and limiting apoptosis. The rapid advancement of space life sciences has spurred considerable interest in the effects of microgravity on stem cells. However, the contribution of glycolytic metabolism to apoptotic regulation under simulated microgravity (SMG) remains unclear. This study examined the influence of SMG on glycolytic activity and apoptosis in human dental pulp stem cells (hDPSCs). Lactic acid and glucose measurements were used to evaluate glycolytic flux, while transcript levels of HK2, PKM2, and LDHA were quantified by qPCR, HK2 and PKM2 protein expression was assessed by Western blotting, and annexin V-FITC/PI staining combined with immunoblotting of apoptosis-related proteins (BAX, BCL-2, and cleaved caspase-3) was performed to assess cell death. SMG markedly increased glycolytic capacity and attenuated apoptosis in hDPSCs. SphK1 expression was also elevated, indicating a role in cell survival. Pharmacological inhibition of SphK1 with PF-543 reduced both glycolysis and the antiapoptotic effect, implicating SphK1 as a critical regulator of these processes. Inhibition of glycolysis by 2-DG further increased apoptosis, confirming the protective role of glycolytic metabolism under SMG. These findings demonstrate that SMG enhances glycolysis and limits apoptosis in hDPSCs via SphK1 upregulation, suggesting that microgravity conditions may augment stem cell survival and function.

Retinal degeneration is the leading cause of blindness worldwide. Subretinal implantation of human retinal progenitor cells (hRPCs) has shown great promise in models of retinal degeneration for restoration of vision but is limited by extremely low (< 2%) integration into the retina. Successful integration of implanted cells requires their migration from the site of implantation into the degenerating retina. Little is known about what cues promote RPC migration in the context of the postimplantation microenvironment, such as cues presented by a biomaterial carrier. We utilized a high-throughput assay to study the migration of hRPCs in three-dimensional hydrogel matrices of varying chemical composition and stiffness and, with exposure to different soluble factors, to identify cues important for hRPC migration and associated cell signaling events driving migration. Collagen type I, collagen type I methacrylate, and hyaluronic acid glycidyl methacrylate gels were developed with variable stiffness. The impact of key growth factors in neural development, regeneration, and cell migration such as epidermal growth factor (EGF), fibroblast growth factor (FGF), stromal cell–derived factor (SDF), and hepatocyte growth factor (HGF) was studied using hRPCs in 2 mg/mL collagen type I gels. Migration of the hRPCs varied significantly in gels of different composition and stiffness, with higher levels of mean migration distance after 48 h in nonphoto crosslinked collagen-based gels with higher concentrations of gel components and associated compressive moduli. In addition, the presence of SDF and HGF in collagen gels increased hRPC migration compared to media alone. Key signaling nodes correlating with hRPC migration were identified in Akt and MAPK signaltransduction pathways using bead-based multiplex ELISA and partial least-squares regression (PLSR) modeling. These results motivate the further exploration of material stiffness and co-delivery of soluble factors as important design parameters in cell delivery vehicles to promote transplanted hRPC migration and successful integration into degenerating retina.

Ex vivo organ perfusion (EVOP) is used for whole organ preservation, and the main focus is to improve the outcome of donor organs for transplantation. Recently, EVOP has found application in disease modeling, drug development, and tissue regeneration. We discuss progress in EVOP research involving small animal organs using benchtop and incubator-based EVOP systems, highlighting innovative designs of EVOP systems, technical specifications of each system, and their versatile applications across a range of research fields.