Abstract P173: Role Of Potassium Intake On Hypertensive Cardiovascular Damage In Apolipoproteine-deficient Mice Under Normal And High Salt Conditions

Abstract

Reduced potassium (k+) intake has been linked to cardiovascular diseases. The underlying mechanisms remain unknown. Here, we investigate the effect of low (0%), normal (0.5%) and high K+ (5%) diet on the development of atherosclerosis and hypertensive cardiac damage. To induce atherosclerosis, apolipoprotein-deficient mice were infused with angiotensin (Ang) II (500ng/kg/min) for 28 days. Potassium treatment was initiated 2 weeks before Ang II infusion. Cardiac function was assessed by MRI. Levels of K+ in the serum and urine were significantly different between groups. The Ang II infused mice from the K+ low group had significantly higher atherosclerotic plaques in the aortic arch (21±3%) compared to K+ high (10±2%) and K+ normal (11±2%) groups. The atherosclerosis development was blood pressure independent since no differences in blood pressure between the groups were observed. Although heart to body-weight ratio did not differ between three groups, K+ low diet was associated with a lower ejection fraction rate and increased mRNA expression levels of cardiac ANP, BNP, collagen and fibronectin compared to the K+ normal and K+ high group. After Ang II infusion, assessment of aldosterone levels in urine showed significant higher aldosterone levels in the high K+ (214±72ng/24h) compared to normal K+ (26±6ng/24h) and low K+ (18±4ng/24h) groups. Aldosterone induced cardiovascular damage is known to be aggravated by sodium. To, evaluate whether high sodium diet unmask aldosterone mediated cardiovascular damage in the high K+ group, mice fed a high or normal K+ diet were additionally treated with high sodium (1% NaCl) in the drinking water. During Ang II treatment, high salt diet accelerated atherosclerosis in the aortic arch of both groups but no differences were observed between the high K+ high/high Na+ (41±7%) and normal K+/high Na+ (49±2%) group. In contrast, high K+/high Na+ group have significantly more severe cardiac hypertrophy compared to normal K+ high Na+ group (8.9±0.7 vs 6.4±0.7mg/g). These results were confirmed by MRI. K+ deficient diet induces atherosclerosis and cardiac damage during Ang II induced hypertension. K+ enriched diet exacerbates cardiac hypertrophy only under high Na+ conditions most likely in an aldosterone-dependent mechanism.