Differentiation of human umbilical cord mesenchymal stem cells into cardiomyocytes: an experimental study

Objective To evaluate the capability of the cardiomyogenic differentiation of human umbilical cord (UC) mesenchymal stem cells (MSCs) in vitro and therapeutic effects on heart function recovery in rats with acute myocardial infarction (MI) post-transplantation. Methods The UC-MSCs were isolated by collagenase and trypsogen digestion, and the 4th to 6th passages of UC-MSCs were collected for 5- azacytidine induction, then identified by imrnunohistochemistry and immunofluorescence. MI models were established in rats and randomly divided into 2 groups (n=10 each): cell transplantation group (received transplantation of cultured UC-MSCs to around infarcted myocardium) and control group. Four weeks later,immunofluorescence was performed to identified the transplanted stem cells, and changes in cardiac function was detected by ultrasound. Results There was a consistent change in morphology of UC- MSCs after induction in vitro. Positive rates of specific α- cardiac actin, myosin and Troponin T after 5- azacytidine induction were over 50%. Four weeks after cell transplantation, the transplanted umbilical cord mesenchymal stem cells survived in infarcted myocardium and differentiated into cardiomyocyte-like cells. Cardiac function test showed greater level of left ventricular ejection fraction (LVEF) in UC-MSCs group four weeks after transplantation [ (68.4± 15.2)% ] compared with control group [ (53.2± 13.4)%, P＜0.05]. Conclusion Human umbilical cord mesenchymal stem cells may differentiate into cardiomyocyte-like cells in vitro and may contribute to recovery of cardiac function. Key words: Stem cell transplantation; Myocytes, cardiac; Myocardial infarction; Actins; 5-azacytidine