Paracrine Factors from Cultured Cardiac Cells Promote Differentiation of Embryonic Stem Cells into Cardiac Myocytes

Embryonic stem (ES) cell-derived cardiac myocytes could be valid source for cell transplantation therapy. The primary goal of the present study is to explore the efficient method to obtain cardiac cells derived from ES cells. We examined the effects of conditioned medium from cultured cardiac cells of neonatal mouse on the differentiation of ES cells toward cardiac myocytes. When Nkx2.5-GFP knock-in ES cells were incubated in the medium extracted from cultured neonatal mouse ventricular myocytes, they showed more efficient differentiation to cardiac myocytes, compared with incubation in the control medium (6.8′1.6 vs 8.6′1.9%, n=4, p<0.05). Neonatal cultured myocytes may produce some paracrine factors which promotes ES cell differentiation to cardiac cells.