Wine grape pomace protects against reperfusion arrhythmias in dysmetabolic rats

Severe reperfusion arrhythmias are associated with increased mortality after acute myocardial infarction. High fat and fructose diet (HFFD) increases arrhythmic risk and predispose to diseases such as diabetes, hypertension, and dyslipidemia.

Wine grape pomace (WGP) is left-over of seeds and skins generated in the winemaking process. It contains relatively high amounts of bioactive components such as dietary fiber and polyphenols. Food rich in polyphenols has been proposed to prevent cardiovascular disease.  

We tested whether rats fed with an HFFD increased arrhythmias during the reperfusion and if a WGP supplementation could counteract this effect.

Male Wistar rats were fed for 6 weeks with control diet (C), HFFD (20 % fat and 20% fructose w/w), and HFFD supplemented with WGP in a dose of 1 g/Kg/day. Isolated hearts were perfused with a Krebs-Henseleit solution and after 15 min stabilization, submitted to 10 min of regional ischemia followed by 5 min of reperfusion. Incidence and severity of arrhythmias were analyzed. In myocardial homogenates, AKT, eNOS, and Nox4 were evaluated by western blot.  

Metabolic syndrome was confirmed in HFFD and WGP groups. HFFD increased ventricular fibrillation incidence (5/6, p<0.01 vs C by Fisher Exact test) and duration (3min 36s, P<0.05 by Kruskal-Wallis) with respect to C (1/10 y 1min) and WGP (1/10 y 1 min). Other arrhythmias occurred in similar proportion in all groups. WGP enhances heart p-AKT and p-eNOS expression and reduces Nox4 expression in the heart

The above results suggest that an HFFD facilitates the occurrence of severe arrhythmias during reperfusion and WGP prevents these events associated with an increase in nitric oxide bioavailability in the heart.