Improved cardiac differentiation of human adipose tissue-derived stem cells using a combination of bFGF and BMP4

Adipose-derived stem cells (ADSCs) represent a promising source of cells for cardiac tissue engineering and repair of the injured heart. However, better understanding of the factors affecting the cardiac differentiation of ADSCs is required before clinical application of these cells. Current study was designed to investigate the role of bFGF and BMP4 in cardiac differentiation of human ADSCs.
ADSCs were isolated from human abdominal subcutaneous adipose tissue and cultured. For cardiac differentiation, ADSCs were treated with 10 ng/ml bFGF and 20, 50 or 100 ng/ml BMP4 in a medium containing 10% FBS or 0.5% B27 for four days. Then the induction factors were completely omitted, and the cells were maintained in 10% FBS-containing medium for up to three weeks. At the end of differentiation period, the expression of some cardiac markers was assessed by RT-PCR, qPCR and immunocytochemistry.
The differentiated ADSCs expressed cardiac-specific genes. Based on qPCR analysis, the maximum expression level of ANF and MLC2A mRNAs was detected in the cells treated with 10 ng/ml bFGF and 20 ng/ml BMP4 in the FBS-containing medium. Moreover, FBS supplementation of induction medium was more effective than the B27-containing medium for cardiac differentiation of ADSCs by bFGF and BMP4. The cells treated with 10 ng/ml bFGF and 20 ng/ml BMP4 in FBS-containing medium expressed cardiac troponin I and α-actinin proteins.
It seems that a combination of bFGF and BMP4 improves cardiac differentiation of ADSCs. Moreover, bFGF and BMP4 are more effective for cardiac differentiation when the induction medium is supplemented with FBS than B27. This may be due to the presence of insulin in B27 supplement.