Coronary reperfusion coupled with mechanical unloading reduced myocardial fibrosis and significantly upregulated cardiomyocyte proliferation to 10.4% compared to 0.5% in loaded reperfused hearts.
Does mechanical unloading coupled with coronary reperfusion improve cardiomyocyte proliferation and prevent fibrosis in a rat model of myocardial infarction?
In a rat model of myocardial infarction, coupling mechanical unloading with coronary reperfusion prevents unloading-induced fibrosis and significantly upregulates cardiomyocyte proliferation.
Absolute Event Rate: 10.4% vs 0.5%
p-value: p=0.0001
Percutaneous left ventricular assist devices (LVADs) have become essential tools during coronary reperfusion in high-risk PCI. Significant reduction in infarct propagation is observed when mechanical unloading is coupled with reperfusion, but little is known of the effect this reduction in wall stress and extracellular matrix with LVADs has on the heart's regenerative capacity. This study investigates the effect coronary reperfusion coupled with mechanical unloading has on myocardial fibrosis, and the impact of these changes in extracellular matrix on the heart's regenerative potential. MI was induced by coronary artery ligation in Lewis rats. Hearts underwent permanent coronary ligation (AMI) or were reperfused after 90 min (AMI/R). In each group, hearts were either loaded (AMI-L or AMI/R-L) or unloaded (AMI-U or AMI/R-U). In the unloaded subgroup, the infarcted hearts were explanted after 90 min and transplanted into the abdomen of healthy recipients via heterotopic abdominal heart-lung transplantation. The recipient's heart acted as control. Hearts were analysed on day 7. 30 hearts were studied. In the permanent ligation group, fibrosis increased in both the loaded and unloaded hearts with no significant rise in cardiomyocyte proliferation. After coronary reperfusion, no increase in fibrosis was observed with mechanical unloading but cardiomyocyte proliferation rose significantly (AMI/R-L vs AMI/R-U p = 0.0001). Cardiomyocyte proliferative rate in the loaded and unloaded hearts was 0.6% and 3.7%, respectively, after permanent ligation, and 0.5% and 10.4%, respectively, after coronary reperfusion. These data show that coronary reperfusion coupled with mechanical unloading reduces myocardial fibrosis and upregulates cardiomyocyte proliferation after myocardial infarction.
Bello et al. (Sat,) conducted a other in Acute myocardial infarction (n=30). Mechanical unloading coupled with coronary reperfusion vs. Coronary reperfusion without mechanical unloading (loaded) was evaluated on Cardiomyocyte proliferative rate (p=0.0001). Coronary reperfusion coupled with mechanical unloading reduced myocardial fibrosis and significantly upregulated cardiomyocyte proliferation to 10.4% compared to 0.5% in loaded reperfused hearts.