Myocardial regeneration after implantation of porcine small intestinal submucosa in the left ventricle

INTRODUCTION Most cardiomyocytes do not regenerate after myocardial infarction. Porcine small intestinal submucosa has been shown to be effective in tissue repair. OBJECTIVE To evaluate myocardial tissue regeneration and functional effects of SIS implantation in pigs after left ventriculotomy. METHODS Fifteen pigs were assigned to two groups: porcine small intestinal submucosa (SIS) (N=10) and control (N=5). The SIS group underwent a mini sternotomy, left ventriculotomy and placement of a SIS patch. The control group underwent a sham procedure. Echocardiography was performed before and 60 days after the surgical procedure. Histological analysis was performed with hematoxylin-eosin stain and markers for actin 1A4, anti sarcomeric actin, connexin43 and factor VIII. RESULTS Weight gain was similar in both groups. Echocardiography analysis revealed no difference between groups regarding end diastolic and systolic diameters and left ventricular ejection fraction, both pre (P=0.118, P=0.313, P=0.944) and post procedure (P=0.333, P=0.522, P=0.628). Both groups showed an increase in end diastolic (P<0,001 for both) and systolic diameter 60 days after surgery (P=0.005, SIS group and P=0.004, control group). New cardiomyocytes, blood vessels and inflammatory reactions were histologically identified in the SIS group. CONCLUSION SIS implantation in pigs after left ventriculotomy was associated with angiomuscular regeneration and no damage in cardiac function.