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We studied the differentiation of embryonic stem cells (ESCs) and developed a novel protocol for generating functional cardiomyocytes (CMs) from ESCs by co-culturing these with live cardiac cells. We then evaluated the structural and functional properties of these ESC-derived CMs (ESCMs). An acellular matrix obtained from rabbit heart tissues was used as a scaffold. Then ESCMs were seeded onto the acellular matrix for preliminary tissue engineering applications. We found that by mimicking the cardiac microenvironment, the percentage of beating embryoid bodies (EBs) was much higher and the homogeneity of EBs were significantly improved over that seen in the control group (p<0.001). ESCMs in EBs acquired almost the same structural and functional properties as typical CMs. After implantation, the cells in the EBs rapidly grew and expanded in the extracellular matrix. These results indicate that the differentiation of ESCs can be controlled in a cardiac mimicking microenvironment and that ESCs can be used as an ideal cell source for large-scale tissue engineering applications for the procurement of cardiac muscle.

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doi:10.1042/CBI20090021 Received 1 June 2009/20 August 2009; Accepted 15 September 2009 Published as Immediate Publication 15 September 2009