Injection of composite with bone marrow-derived mesenchymal stem cells and a novel synthetic hydrogel after myocardial infarction: a protective role in left ventricle function.

A number of studies have shown that the transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) into the thinned infarct wall improves regional wall motion. In this study, we hypothesized that the injection of biomaterials and MSCs into the infarcted myocardium can preserve left ventricular (LV) function. To test this hypothesis, anterior acute myocardial infarction (AMI) was induced in 34 rabbits and BMSCs with hydrogel composite were prepared. One week after inducing AMI, 28 of the 34 rabbits were divided into four groups (Groups A-D; three rabbits were used for bone marrow aspiration, and three rabbits died) and all received an epicardial injection. Group A received BMSCs with hydrogel composite marked by 5-bromodeoxyuridine (BrdU); Group B received BMSCs only marked by BrdU; Group C received hydrogel only marked by BrdU; and Group D was the control group, which received fetal bovine serum. Echocardiography was performed before AMI was induced, 1 week after AMI, and 4 weeks after the epicardial injection. The results were compared with those before AMI, and the rabbits of all the four groups had significantly larger LV end-diastolic diameter (LVDd), thinner anterior wall (AW), lower LV ejection fraction (LVEF), lower VS and VE (p<0.05) 1 week after AMI, which were more significant in Group A (p<0.05). Compared with 1 week after AMI, Group A and Group B had significantly smaller LVDd, thicker AW, larger LVEF, larger VS and VE (p<0.05) 4 weeks after the epicardial injection, which were more significant in Group A (p<0.05); however, there was no significant difference in Group C and Group D. These results suggested that BMSCs with hydrogel composite could serve as an injectable biomaterial that prevents LV remodeling and dilation, and improves local systolic and diastolic function after AMI.