P4.9 ENDOTHELIN-1 IS LINKED WITH ARTERIAL STIFFNESS AND INTERLEUKIN-6 IN BLACK SOUTH AFRICAN WOMEN: THE SABPA STUDY

Abstract

Up-regulation of ET-1 activates inflammatory cells such as macrophages that release pro-inflammatory mediators such interleukin-6 which promote vascular inflammation and endothelial dysfunction, leading to arterial stiffness. Included in this study were 194 black and 197 white South-Africans. Cardiovascular variables were recorded using the Finometer and the Compliar. ET-1 and interleukin-6 were determined by recognized biochemical methods. The participants were divided into black and white men and women due to significant interactions of ethnicity (F(391) = 6.78; p < 0.001) and gender (F(391) = 2.39; p < 0.05) on the association of ET-1 with systolic blood pressure. No significant difference in ET-1 levels between black and white groups emerged. Black men and women had higher blood pressure and pulse wave velocity in comparison to white men and women (p < 0.05). C-reactive protein and interleukin-6 were higher in the black groups compared to the white group (all p < 0.05). A positive correlation (single) existed between ET-1 and interleukin-6 (r = 0.27; p = 0.007), systolic blood pressure (r = 0.27; p = 0.008), pulse pressure (r = 0.25; p = 0.014) and pulse wave velocity (r = 0.23; p = 0.026) in black women. After partial adjustments for BMI and GGT the correlation remains. With forward stepwise multiple regression ET-1 associated with interleukin-6 (adj.R2= 0.13, β=0.278, P=0.005) and measures of arterial stiffness. ET-1 independently associated with systolic blood pressure, pulse pressure and interleukin-6 in black women. Our results suggest that adverse endothelial function is potentially driven by pro-inflammation.