Objective: This study was to investigate the proliferation and differentiation of rat adipose stromal cells when implanted into ischemic myocardium and the improvement of heart function.
Methods: Sprague-Dawley rat adipose tissue was digested with collagenase type I solution and adipose stromal cells were derived by culture. The cells' surface phenotype was examined by flow cytometry. Adipose stromal cells labeled with 4'6-diamidino-2-phenylindole (adipose stromal cells group) or Dulbecco's modified Eagle medium (control group) was transplanted into the ischemic myocardium, which was produced by ligation of left descending branch of coronary artery. At 1 and 4 weeks after transplantation, specimens were acquired from infarcted area and also echocardiography was done to detect the effects on heart function. Then, cell morphology and capillary density were measured, and vascular endothelial growth factor expression levels were assayed by reverse transcription-PCR and enzyme-linked immunosorbent assay.
Result: Adipose stromal cells derived by culture expressed CD44 and CD90 but not CD31 or CD45. Adipose stromal cells were alive at 1 and 4 weeks after transplantation and had a trend toward differentiation into vascular endothelial cells. The number of capillary vessels in peri-infarct area in adipose stromal cells group increased significantly compared with control group (P<0.01). The levels of vascular endothelial growth factor mRNA and protein expression at 1 week increased significantly in adipose stromal cells group compared with control group (P<0.01). Left ventricular function, including ejection fraction and fractional shortening, was higher in adipose stromal cells group when compared with control group at 4 weeks (P<0.01).
Conclusion: Adipose stromal cells transplantation can accelerate angiogenesis in infarcted area after rat myocardial infarction and can improve heart function.