Background: This study was designed to investigate the efficacy of the combined procedure of left ventricular (LV) repair and fetal cardiomyocyte transplantation (CM-TX) in a rat myocardial infarction model.
Methods and results: A moderate-sized LV aneurysm was created by proximal ligation of the left coronary artery in 47 Lewis rats. Four weeks later, they were underwent another operation and received culture medium injection (n=10; group I), fetal CM-TX (n=10; group II), purse-string LV repair with culture medium injection (n=14; group III), or LV repair with fetal CM-TX (n=13; group IV). They were echocardiographically followed-up during the subsequent 4 weeks, and cardiac catheterization was performed in the final week. In the late period, LV dimension in group IV was smaller than that in group III (end-diastolic dimension, 0.92+/-0.02 versus 1.01+/-0.03 cm, P=0.0090; end-systolic dimension, 0.62+/-0.02 versus 0.74+/-0.04 cm, P=0.0093; at the fourth week), although they initially showed similar decreases in both groups. At the final week, end-systolic elastance was higher in group IV than in groups I, II, or III (0.61+/-0.10 versus 0.19+/-0.03, 0.30+/-0.09, 0.33+/-0.07 mm Hg/ micro L, P=0.0002, 0.0037, and 0.0042, respectively).
Conclusions: Fetal CM-TX exerted preventive effects against late LV dilation and dysfunction after LV repair in the rat model. The results suggest that repair surgery combined with fetal CM-TX may enhance the surgical benefits for patients with LV aneurysm in the long term.