EFFECT OF INTERLEUKIN-10 AND LAMINAR SHEAR STRESS ON ENDOTHELIAL NITRIC OXIDE SYNTHASE AND NITRIC OXIDE IN AFRICAN AMERICAN HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS

Background: African Americans have a predisposition to heightened systemic inflammation and a high prevalence of hypertension. Objective: The purpose of this study was to evaluate the influence of interleukin-10 (IL-10) and laminar shear stress (LSS) on African American endothelial cells by measuring total endothelial nitric oxide synthase (eNOS) protein expression and its phosphorylated form (p-eNOS) at Serine 1177, and nitric oxide (NO) levels, in response to IL-10 incubation and high physiological levels of LSS, used as an in vitro mimetic for aerobic exercise training (AEXT). Design: Human umbilical vein endothelial cells (HUVEC) from an African American donor were cultured. The experimental conditions included Static, Static with IL-10 Incubation, LSS at 20 dynes/cm(2), and LSS at 20 dynes/cm(2) with IL-10 Incubation. Western blotting was used to measure eNOS and p-eNOS protein expression in the cells. A modified Griess assay was used to measure NO metabolites in the cell culture media. Results: There were significant increases in p-eNOS, eNOS, and NO in the LSS at 20 dynes/cm(2) and LSS at 20 dynes/cm(2) with IL-10 Incubation experimental conditions when compared to the Static experimental condition. There were no other statistically significant differences demonstrating that IL-10 did not have an additive effect on eNOS activity in our study. Conclusion: The significant increases in p-eNOS, eNOS, and NO as a result of LSS in African American HUVECs suggest that AEXT may be a viable, nonpharmacologic method to improve vascular inflammation status and vasodilation, and thereby contribute to hypertension reduction in the African American population.