Ex vivo cartilage explant model for the evaluation of chondrocyte-targeted exosomes

There is no efficient tracking system available for the therapeutic molecules delivered to cartilage.The dense matrix covering the cartilage surface is the main biological barrier that the therapeutic molecules must overcome.In this study,we aimed to establish a system that can dynamically and effectively track the therapeutic molecules delivered to cartilage.To this aim,we adopted bovine and human cartilage explants as ex vivo models for chondrocyte-targeted exosome dispersion.The efficiency of drug delivery was evaluated using frozen sections.The results of this study showed that the penetration and distribution of chondrocyte-targeted exosomes in cartilage explants can be tracked dynamically.Thus,ex vivo cartilage explants provide an effective and economic system to evaluate therapeutic drugs encapsulated in chondrocyte-targeted exosomes in preclinical studies.

One-step fabrication of cell sheet-laden hydrogel for accelerated wound healing

Full-thickness skin wounds are have continued to be reconstructive challenges in dermal and skin appendage regeneration, and skin substitutes are promising tools for addressing these reconstructive procedures. Herein, the one-step fabrication of a cell sheet integrated with a biomimetic hydrogel as a tissue engineered skin for skin wound healing generated in one step is introduced. Briefly, cell sheets with rich extracellular matrix, high cell density, and good cell connections were integrated with biomimetic hydrogel to fabricate gel + human skin fibroblasts (HSFs) sheets and gel + human umbilical vein endothelial cells (HUVECs) sheets in one step for assembly as a cell sheet-laden hydrogel (CSH). The designed biomimetic hydrogel formed with UV crosslinking and ionic crosslinking exhibited unique properties due to the photo-generated aldehyde groups, which were suitable for integrating into the cell sheet, and ionic crosslinking reduced the adhesive force toward the substrate. These properties allowed the gel + cell sheet film to be easily released from the substrate. The cells in the harvested cell sheet maintained excellent viability, proliferation, and definite migration abilities inside the hydrogel. Moreover, the CSH was implanted into a full-thickness skin defects to construct a required dermal matrix and cell microenvironment. The wound closure rate reached 60.00 ± 6.26% on the 2nd day, accelerating mature granulation and dermis formation with skin appendages after 14 days. This project can provide distinct guidance and strategies for the complete repair and regeneration of full-thickness skin defects, and provides a material with great potential for tissue regeneration in clinical applications.

前交叉韧带重建术后评估何时重返运动指标的研究进展

前交叉韧带重建术(ACLR)是前交叉韧带(ACL)损伤最常用的治疗手段。术后重返运动(RTS)是医生和患者共同关注的问题。在现有文献中,评估患者RTS时机的标准尚未达成一致。常用的评价指标包括术后时间、下肢肌力、功能评分和单腿跳跃测试。近年来,研究学者开始更多地关注单腿跳跃测试。本文将就以上评价指标和单腿跳跃测试进行归纳总结,旨为临床医生评估重返运动时机提供参考。