Journal of Tissue Engineering and Regenerative Medicine最新文献

Regenerative medicine (RM) exploits stem cells to construct biological replacements and repair damaged tissues, offering an alternative to daunting organ transplantation. Even while RM has advanced quickly, building an entire organ remains beyond our capabilities. Experts are thus investigating the adoption of biologically generated composites that preserve the tissue’s crucial physiological, morphological, and mechanical characteristics. Noncellular tissues like extracellular matrix offer cells a milieu similar to their physiological niche, becoming a promising substitute for synthetic composites. In this context, amnion, the membrane enclosing the fetus, is a great contender since it is widely obtainable and economical. Given its biochemical and anatomic characteristics, and the extensive supply of stem cells, growth factors, and matrix proteins, the amnion is considered a fantastic candidate to employ in RM. Decellularized amniotic membrane (DAM) has many uses as two- and three-dimensional scaffolds, anchoring for cell adhesion and expansion for tissue regeneration, and as carrier systems for cell and drug cargoes. The present research aims to assess the recent surge in DAM-RM research, potentially to get beyond the existing barriers impeding the RM’s clinical translation landscape. The present paper draws a comprehensive picture of the experimental evidence and clinical trials regarding exploiting DAM in RM.

Despite ongoing efforts, the regeneration of critical-sized bone defects remains a significant challenge for clinicians due to the absence of a standard clinically compliant bone tissue engineering protocol. These challenges are mostly attributed to the inadequacies of current methods, characterized by their high variability and the reliance on animal-derived components, such as fetal bovine serum (FBS) in cell culture. To address these shortcomings, our approach diverges from conventional practices by prioritizing consistency and reproducibility, and the complete elimination of animal derivatives throughout the entire process. We have developed a novel method that utilizes a peptide-functionalized photocrosslinkable methacrylated hyaluronic acid (MeHA–RGD) hydrogel as a cell sealant for loading human adipose-derived stem cells (hASCs) into a 3D porous polycaprolactone–tricalcium phosphate (PCL–TCP) scaffold. Additionally, we created a 3D-printed vacuum-assisted cell loading device to facilitate this process and ensure efficiency and consistency during cell loading. Our findings indicate that the MeHA–RGD hydrogel supports both stem cell viability and osteogenic differentiation, demonstrating outcomes comparable to those achieved with fibrin glue, a conventional cell sealant widely used in BTE from autologous or xenogeneic sources, even under serum- and xeno-free conditions. In the pursuit of clinical translation, it is vital that biomaterials exhibit low variability, are easily accessible, readily available, and completely free of animal derivatives. To our knowledge, this is the first study to employ a 3D-printed vacuum-assisted cell loading device system within a fully defined hybrid 3D system under complete serum- and xeno-free conditions. These findings unravel and encourage alternative approaches in addressing the existing challenges in BTE, thereby facilitating and accelerating clinical translation in the future.

Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) are used to model cardiac development and disease. This requires a robust population of mature CMs and external stimuli to mimic the complex environment of the heart. In effort toward this maturation, previous groups have applied electrical stimulation (ES) to CMs with varying results depending on the stimulation duration, frequency, and pattern. As such, there is an uncertainty surrounding the timeline on which stimulated iPSC-CMs begin to show early signs of maturation in comparison with their nonstimulated counterparts. Here, we introduce a low-cost custom bioreactor capable of delivering tunable ES to standard 2D cell monolayers. We show that, after exposure to short-term ES, stimulated CMs express early signs of maturation compared to nonstimulated controls. Changes to contractility and protein expression indicate cellular rearrangement within cell monolayers and induction of partial maturation in response to ES. While early signs of maturation are present after 3-4 days of ES, additional cellular structures must develop to reach complete maturation. We also show that this bioreactor can electrically stimulate cardiac fibroblasts (cFBs) and may induce alignment of cFB. We have shown that our custom ES bioreactor can be easily integrated into standard in vitro cell culture platforms to induce measurable changes in both CMs and cFB, exhibiting its potential for promoting crucial CM maturation and cell alignment for cardiac tissue engineering applications.

Managing large, critical-sized bone defects poses a complex challenge, especially when autografts are impractical due to their size and limited availability. In such situations, the development of synthetic bone implants becomes crucial. These implants can be carefully designed and manufactured as potential bone substitutes, offering controlled parameters such as porosity, hardness, and osteogenic cues. In this study, we employed digital light processing (DLP) technology to construct an alumina ceramic scaffold featuring a triply periodic minimal surface (TPMS) structure for bone transplantation. The scaffold was filled with type I collagen to enhance cell infiltration [1], thereby increasing the total surface area. In addition, type I collagen is a carrier for both bone morphogenetic protein-2 (BMP-2) and zoledronic acid (ZA). Using a clinically relevant rabbit cranium defect model, the scaffold underwent in vivo assessment for its functionality in repairing critical-sized bone defect (approximately 8 mm). Four groups of animal experiments were carried out including the control group, the gyroid scaffold group, the type I collagen-loaded scaffold group, and the bioactive factor-functionalized scaffold group. Our animal-based study results revealed that the gyroid scaffold, functionalized with bioactive molecules, provided a conductive surface for promoting increased bone formation and enhancing the healing process in critical-sized long bone and cranium defects. These findings offer preclinical evidence, supporting the use of a TPMS structure composite scaffold and present compelling support for its application as an advanced synthetic bone substitute in the future.

Background: The induced membrane (IM) preclinical models have been described in small animals, but few studies have looked at bone regeneration achievement. The optimisation and validation of such a preclinical model, considering the results obtained after the use of biomaterials as a substitute for bone grafting, could lead to simplifying the surgical procedure and enhance the clinical results.

Methods: An in vivo model of the IM technique was developed on the femur of Lewis rats after a 4-mm critical bone defect stabilised with an osteosynthesis plate. A first optimisation phase was performed by evaluating different osteotomy methods and two different osteosynthesis plate sizes. The efficiency of the model was evaluated by the failure rate obtained 6 weeks after the first operative time. Thereafter, bone regeneration was evaluated histologically and radiologically at 24 weeks to confirm the critical nature of the bone defect (negative control), the effectiveness of the IM with a syngeneic bone graft (positive control) and the possibility of using a biomaterial (GlassBone Noraker) in this model.

Results: Sixty-three rats were included and underwent the first surgical step. Nineteen rats subsequently underwent the second surgical step. The results obtained led to select piezotomy as the best osteotomy technique and 1-mm-thick plates with 2.0-mm-diameter screws as osteosynthesis material. Twenty-four weeks after the second surgical step, solely the group with both surgical steps and a syngeneic bone graft showed complete ossification of the bone defect. In contrast, the group without a graft did not present a suitable ossification, which confirms the critical nature of the defect. IM produced an incomplete bone regeneration using GlassBone alone.

Conclusions: A piezotome osteotomy with an osteosynthesis plate of sufficient stiffness is required for this two-stage bone regeneration model in rats. The 4-mm bone defect is critical for this model and suitable for biomaterial evaluation.

Bone marrow–derived mesenchymal stem cells (BM-MSCs) are well established for their osteogenic potential but are prone to senescence with aging or in vitro expansion. Drug treatments that reduce cellular senescence may enhance the regenerative capacity of BM-MSCs. This study investigates the effects of losartan and fisetin, both separately and in combination, on cellular senescence and osteogenesis. Human BM-MSCs were exposed to low and high concentrations of each drug for 24 h. Our findings showed that high-dose losartan exhibited cytotoxicity, focusing subsequent analyses on the low doses. Both low-dose losartan and fisetin effectively mitigated cellular senescence, with combined treatment showing synergistic effects in reducing senescence markers. From these initial findings, subsequent experiments utilized low doses of both compounds to evaluate their effect on differentiation capacity. Our multimodal approach, incorporating flow cytometry, senescence-associated heterochromatin foci (SAHF) immunohistochemistry, senescence-associated secretory phenotype (SASP) quantification, and differentiation potential assays, revealed that the combination of 23.6 μM of losartan and 50 μM of fisetin was optimal for reducing cellular senescence and enhancing osteogenesis in BM-MSCs. These results support potential therapeutic strategies to counteract age-related declines in bone health and improve healing. By targeting cellular senescence while promoting osteogenesis, losartan and fisetin offer promising avenues for future research aimed at enhancing the regenerative capacity of BM-MSCs in the context of musculoskeletal regenerative medicine.