Fabrication of cartilage tissue substitutes from cells with induced pluripotency
One of the approaches to cartilage tissue restoration problem relies on cellular technologies that use iPSCs, induced pluripotency stem cells that are an unlimited source of cellular material for tissue engineering with significant differentiation potential. However, there are no standardized protocols for chondrogenic differentiation of iPSCs. This study aimed to make cartilage tissue samples using 3D spheroid cultures and following four chondrogenic differentiation protocols, then compare characteristics of the cartilage samples made under different protocols and isolate the most effective way of differentiation. The iPSCs were differentiated chondrogenically, the four protocols were "long", "short", "combined" and with conditioned medium from a primary culture of autologous chondrocytes; the combinations of TGFβ1, BMP2, Chir 99021, and PK factors varied. Microwell plates were used to make spheroids. Immunocytochemical staining, real-time PCR and histological staining enabled assessment of the synthesis and expression profiles. High rates of synthesis and expression of chondrogenic markers Sox9, aggrecan, type II collagen were observed in spheroids experimented with under the "long", "combined" protocols and the conditioned medium protocol. The "combined" differentiation protocol made chondrogenesis most effective, and conditioned medium was highly efficient in inducing and supporting chondrogenic differentiation.
Keywords: tissue engineering, articular cartilage, induced pluripotency stem cells (iPSCs), spheroids, chondrogenesis