Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, Shanghai, PR China; National Tissue Engineering Center of China, Shanghai, PR China.
Department of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Tissue Engineering, Shanghai, PR China.
Acta Biomater. 2017 May;54:321-332. doi: 10.1016/j.actbio.2017.03.031. Epub 2017 Mar 22.
In vivo niche plays an important role in regulating differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. This study explored the feasibility that chondrocyte sheet created chondrogenic niche retained chondrogenic phenotype of BMSC engineered cartilage (BEC) in subcutaneous environments. Porcine BMSCs were seeded into biodegradable scaffolds followed by 4weeks of chondrogenic induction in vitro to form BEC, which were wrapped with chondrocyte sheets (Sheet group), acellular small intestinal submucosa (SIS, SIS group), or nothing (Blank group) respectively and then implanted subcutaneously into nude mice to trace the maintenance of chondrogenic phenotype. The results showed that all the constructs in Sheet group displayed typical cartilaginous features with abundant lacunae and cartilage specific matrices deposition. These samples became more mature with prolonged in vivo implantation, and few signs of ossification were observed at all time points except for one sample that had not been wrapped completely. Cell labeling results in Sheet group further revealed that the implanted BEC directly participated in cartilage formation. Samples in both SIS and Blank groups mainly showed ossified tissue at all time points with partial fibrogenesis in a few samples. These results suggested that chondrocyte sheet could create a chondrogenic niche for retaining chondrogenic phenotype of BEC in subcutaneous environment and thus provide a novel research model for stable ectopic cartilage regeneration based on stem cells.
In vivo niche plays an important role in directing differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. The current study demonstrated that chondrocyte sheet generated by high-density culture of chondrocytes in vitro could cearte a chondrogenic niche in subcutaneous environment and efficiently retain the chondrogenic phenotype of in vitro BMSC engineered cartilage (vitro-BEC). Furthermore, cell tracing results revealed that the regenerated cartilage mainly derived from the implanted vitro-BEC. The current study not only proposes a novel research model for microenvironment simulation but also provides a useful strategy for stable ectopic cartilage regeneration of stem cells.
体内生态位在调节干细胞的分化命运中起着重要作用。由于缺乏合适的软骨生成生态位，骨髓基质细胞（BMSCs）在皮下环境中的稳定软骨再生一直是一个巨大的挑战。本研究探讨了在皮下环境中，由软骨细胞片创建的软骨生成生态位保留 BMSC 工程软骨（BEC）软骨生成表型的可行性。将猪 BMSCs 接种到可生物降解的支架中，然后在体外进行 4 周的软骨诱导，形成 BEC，将其分别用软骨细胞片（Sheet 组）、无细胞的小肠黏膜下层（SIS，SIS 组）或无任何包裹（Blank 组）包裹，然后植入裸鼠皮下以追踪软骨生成表型的维持情况。结果表明，Sheet 组中的所有构建体均显示出典型的软骨特征，具有丰富的腔隙和软骨特异性基质沉积。随着体内植入时间的延长，这些样本变得更加成熟，除了一个未完全包裹的样本外，所有时间点均未见明显的成骨迹象。Sheet 组中的细胞标记结果进一步表明，植入的 BEC 直接参与了软骨形成。SIS 和 Blank 组中的样本在所有时间点主要显示出骨化组织，少数样本中存在部分纤维化。这些结果表明，软骨细胞片可以为 BEC 在皮下环境中保留软骨生成表型创造一个软骨生成生态位，从而为基于干细胞的稳定异位软骨再生提供一个新的研究模型。
体内生态位在指导干细胞的分化命运中起着重要作用。由于缺乏合适的软骨生成生态位，骨髓基质细胞（BMSCs）在皮下环境中的稳定软骨再生一直是一个巨大的挑战。本研究表明，体外通过高密度培养软骨细胞生成的软骨细胞片可以在皮下环境中创建一个软骨生成生态位，并有效地保留体外 BMSC 工程软骨（vitro-BEC）的软骨生成表型。此外，细胞示踪结果表明，再生的软骨主要来源于植入的 vitro-BEC。本研究不仅提出了一种新的微环境模拟研究模型，还为干细胞的稳定异位软骨再生提供了一种有用的策略。
