Elevated Aldosterone at Birth Predicts Renal Function Decline in Low Birth Weight Rats

Abstract

Epidemiological and experimental studies reported elevated aldosterone levels in low birth weight individuals. However, the effect of this finding on renal function after ischemic events is unknown. The objective of this study was to investigate the effects of elevated aldosterone at birth on renal function after ischemia in later life. We used low birth weight rats exposed to bilateral mild renal ischemia (15 min) and treated with acute infusion of angiotensin converter enzyme inhibitor Enalaprilat. At 12 weeks of age male and female, control and low birth weight rats were exposed to renal ischemia or sham, and treated with Enalaprilat or vehicle. Systemic and renal hemodynamic were measured 2 hours after ischemia, followed by blood and tissue collection. GraphPad software was used for statistical analysis with significances set at P<0.05. Aldosterone levels measured at birth and 12 weeks of age were elevated (P<0.05) in male low birth weight rats compared to females counterparts and controls. Mean arterial pressure was elevated (P<0.05) in male low birth weight rats compared to female counterpart and controls. Mild renal ischemia exacerbated increases in Aldosterone and mean arterial pressure; and induced reductions in glomerular filtration rate and renal blood flow (P<0.05), and increases in renal vascular resistance (P<0.05) only in male low birth weight rats. Enalaprilat reverted changes observed in male low birth weight rats, while did not affect female counterpart and controls. This study suggest that elevated aldosterone at birth predicts renal function decline after ischemia event in low birth weight rats with sex dimorphism and involvement of the renin angiotensin system