Circulating Hydrogen Sulfide (H(2)S) and Nitric Oxide (NO) Levels Are Significantly Reduced in HIV Patients Concomitant with Increased Oxidative Stress Biomarkers

Human immunodeficiency virus (HIV) attacks the immune system and weakens the ability to fight infections/disease. Furthermore, HIV infection confers approximately two-fold higher risk of cardiac events compared with the general population. The pathological mechanisms responsible for the increased incidence of cardiovascular disease in HIV patients are largely unknown. We hypothesized that increased oxidative stress and attenuated circulating levels of the cardioprotective gaseous signaling molecules, nitric oxide (NO), and hydrogen sulfide (H(2)S) were involved in the cardiovascular pathobiology observed in HIV patients. Plasma samples from both HIV patients and age–matched normal subjects were used for all assays. Oxidative stress was determined by analyzing the levels of advanced oxidation protein products (AOPP) and H(2)O(2). Antioxidant levels were determined by measuring the levels of trolox equivalent capacity. ADMA, hs-CRP, and IL-6 were determined by using ELISA. The levels of H(2)S (free H(2)S and sulfane sulfur) and NO(2) (nitrite) were determined in the plasma samples by using gas chromatography and HPLC, respectively. In the present study we observed a marked induction in the levels of oxidative stress and decreased antioxidant status in the plasma of HIV patients as compared with the controls. Circulating levels of the cardiovascular disease biomarkers: ADMA, hs-CRP (high-sensitivity C-reactive protein), and IL-6 were significantly increased in the circulatory system of HIV patients. The levels of both nitrite and H(2)S/sulfane sulfur were significantly reduced in the plasma of HIV patients as compared with normal subjects. Our data demonstrate significant increases in circulating biomarkers of oxidative stress and cardiovascular (CV) in conjunction with decreased bioavailability of H(2)S and NO in HIV patients. Diminished levels of these two cardioprotective gaseous signaling molecules may be involved in the pathogenesis of CV disease in the setting of HIV.