Chondrogenic differentiation of human umbilical cord blood-derived mesenchymal stem cells in vitro

Different therapeutic techniques have been developed for regeneration of articular cartilage injuries, but none has provided an optimal solution to their treatment. Human umbilical cord blood-mesenchymal Stem Cells (HUCB-MSCs) have been considered as promising alternative cell source for cartilage repair. Objectives: Examining the success rate of MSCs isolation from HUCB as well as chondrogenic differentiation potential of HUCB-MSCs in vitro. Materials and methods: 32 UCB samples were collected, in addition to 5 bone marrow (BM) and 5 peripheral blood (PB) samples, taken as reference controls. Samples were used for mononuclear cells isolation from which MSCs were expanded under complete aseptic conditions, were verified morphologically and through the presence of CD44 and CD105, and absence of CD34. Results: Success rate of UCB-MSCs isolation was (25%), a rate that was lower than those of PB (40%) and BM (80%). Accordingly, certain input parameters have been recommended for successful MSCs isolation from UCB. On selecting samples in which recommended parameters were fulfilled, success rate was increased to 72%. This was together with providing optimal experiment conditions; mainly type of expansion medium, success rate reached 80%. Then, successfully expanded MSCs were subjected to chondrogenic differentiation by culturing in pelleted micromass system in presence of transforming growth factor beta-1 and chondrogenic medium devoid of fetal bovine serum to evaluate their ability to undergo chondrogenesis. Differentiation was verified microscopically using special stains, and proved by reverse transcriptase-polymerase chain reaction for expression of aggrecan and collagen II genes. In conclusion, in vitro differentiation into chondrocytes is possible from HUCB-MSCs. Microsc. Res. Tech. 78:667-675, 2015. (c) 2015 Wiley Periodicals, Inc.