Abstract 55: Hiv Viral Proteins Elevate Blood Pressure And Impairs Endothelial Function In Resistance Arteries Via Sex Specific, Immune And Nox1-dependent Mechanisms In Mice.

Abstract

Thanks to the onset of combination antiretroviral therapy (cART), patients living with HIV live longer but experience accelerated rates of hypertension. However, the etiology of HIV-associated hypertension remains ill defined, specifically the respective contributions of repressed viral infection and cART treatment. Herein, we took advantage of a transgenic model (Tg26) of repressed viral infection to investigate the contribution of HIV viral proteins to hypertension. Quantification of inflammatory cytokines revealed elevated circulating TNFα levels but also high aorta and intraperitoneal immune cells TNFα in male Tg26 mice leading to the hypothesis that HIV-associated hypertension involves immune-derived TNFα secretion and endothelial dysfunction in males and females Tg26 mice. Blood pressure (BP) was measured via radio telemetry and vascular reactivity studies performed via wire myography. BP analysis revealed increased mean arterial pressure (MAP: male: WT=112.3±1.3 vs Tg26=121.9±4.0 mmHg/ female: WT=110.6±3.01/ Tg26=120.3±6.9 mmHg) and heart rate in both sexes (P<0.05). However, blockade of TNFα action with etanercept restored BP and aortic endothelial function in male Tg26 mice only. Along with an increase in TNFα, male Tg26 aortas showed infiltration of Tcells and proinflammatory cytokines IL-18, and IL-6, which were not seen in females. However, scavenging of reactive oxygen species with the selective NOX1 inhibitor GKT771 restored aorta endothelial function in both sexes. A contributor to hypertension is impaired endothelial relaxation in resistance arteries. Mesenteric arteries showed impaired endothelial relaxation to acetylcholine in both male and female Tg26 mice (P<0.05) with no impairment in smooth muscle cell relaxation. This phenotype was reproduced in WT mice transplanted with Tg26 bone marrow (BM) and remarkably reversed in Tg26 mice receiving WT BM supporting a clear role for immune cells in endothelial dysfunction. Collectively, these data indicate that HIV-related hypertension involves immune and NOX1-dependent endothelial dysfunction in both sexes but TNFα-dependent mechanisms in males only providing evidence of sex specific mechanisms.