Sheehy Eamon J, Mesallati Tariq, Vinardell Tatiana, Kelly Daniel J
Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland; Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.
School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland.
Acta Biomater. 2015 Feb;13:245-53. doi: 10.1016/j.actbio.2014.11.031. Epub 2014 Nov 24.
Cartilaginous tissues engineered using mesenchymal stem cells (MSCs) have been shown to generate bone in vivo by executing an endochondral programme. This may hinder the use of MSCs for articular cartilage regeneration, but opens the possibility of using engineered cartilaginous tissues for large bone defect repair. Hydrogels may be an attractive tool in the scaling-up of such tissue engineered grafts for endochondral bone regeneration. In this study, we compared the capacity of different naturally derived hydrogels (alginate, chitosan and fibrin) to support chondrogenesis and hypertrophy of MSCs in vitro and endochondral ossification in vivo. In vitro, alginate and chitosan constructs accumulated the highest levels of sulfated glycosaminoglycan (sGAG), with chitosan constructs synthesizing the highest levels of collagen. Alginate and fibrin constructs supported the greatest degree of calcium accumulation, though only fibrin constructs calcified homogeneously. In vivo, chitosan constructs facilitated neither vascularization nor endochondral ossification, and also retained the greatest amount of sGAG, suggesting it to be a more suitable material for the engineering of articular cartilage. Both alginate and fibrin constructs facilitated vascularization and endochondral bone formation as well as the development of a bone marrow environment. Alginate constructs accumulated significantly more mineral and supported greater bone formation in central regions of the engineered tissue. In conclusion, this study demonstrates the capacity of chitosan hydrogels to promote and better maintain a chondrogenic phenotype in MSCs and highlights the potential of utilizing alginate hydrogels for MSC-based endochondral bone tissue engineering applications.
使用间充质干细胞（MSC）构建的软骨组织已被证明可通过执行软骨内程序在体内生成骨。这可能会阻碍将MSC用于关节软骨再生，但为使用工程化软骨组织修复大的骨缺损开辟了可能性。水凝胶可能是扩大此类用于软骨内骨再生的组织工程移植物规模的一种有吸引力的工具。在本研究中，我们比较了不同天然来源的水凝胶（藻酸盐、壳聚糖和纤维蛋白）在体外支持MSC软骨生成和肥大以及在体内支持软骨内骨化的能力。在体外，藻酸盐和壳聚糖构建体积累了最高水平的硫酸化糖胺聚糖（sGAG），壳聚糖构建体合成了最高水平的胶原蛋白。藻酸盐和纤维蛋白构建体支持最大程度的钙积累，不过只有纤维蛋白构建体均匀钙化。在体内，壳聚糖构建体既不促进血管化也不促进软骨内骨化，并且还保留了最多的sGAG，这表明它是用于关节软骨工程的更合适材料。藻酸盐和纤维蛋白构建体都促进了血管化和软骨内骨形成以及骨髓环境的发育。藻酸盐构建体在工程组织的中央区域积累了显著更多的矿物质并支持更大的骨形成。总之，本研究证明了壳聚糖水凝胶促进并更好地维持MSC软骨生成表型的能力，并突出了利用藻酸盐水凝胶用于基于MSC的软骨内骨组织工程应用的潜力。
