Autologous transplantation of bone marrow cells improves damaged heart function

Background-Autologous bone marrow cells (BMCs) transplanted into ventricula r scar tissue may differentiate into cardiomyocytes and restore myocardial function. This study evaluated cardiomyogenic differentiation of BMCs, thei r survival in myocardial scar tissue, and the effect of the implanted cells on heart function. Methods and Results-In vitro studies: BMCs from adult rats were cultured in cell culture medium (control) and medium with 5-azacytidine (5-aza, 10 mu mol/L), TGF beta 1 (10ng/mL), or insulin (1 nmol/L) (n=6, each group). Only BMCs cultured with 5-aza formed myotubules which stained positively for tr oponin I and myosin heavy chain. In vivo studies: a cryoinjury-derived scar was formed in the left Ventricular free wall. At 3 weeks after injury, fre sh BMCs (n=9), cultured BMCs (n=9), 5-aza-induced BMCs (n=12), and medium ( control, n=12) were autologously transplanted into the scar. Heart function was measured at 8 weeks after myocardial injury. Cardiac-like muscle cells which stained positively for myosin heavy chain and troponin I were observ ed in the scar tissue of the 3 groups of BMC transplanted hearts. Only the 5-aza-treated BMC transplanted hearts had systolic and developed pressures which were higher (P<0.05) than that of the control hearts. All transplante d BMCs induced angiogenesis in the scar. Conclusions-Transplantation of BMCs induced an,angiogenesis. BMCs cultured with 5-aza differentiated into cardiac-like muscle cells in culture and in vivo in ventricular scar tissue and improved myocardial function.