Comprehensive assessment of the arginine pathway and its relationship to inflammation in HIV.

BACKGROUND: Nitric oxide helps maintain vascular function and is generated through the oxidation of arginine. Whether altered arginine metabolism may lead to elevated levels of inflammation in HIV is unclear. METHODS: We performed a cross-sectional analysis of HIV-infected adults on stable antiretroviral therapy with HIV-1 RNA less than 50 copies/ml and HIV-uninfected controls. We measured biomarkers in the arginine pathway, markers of systemic inflammation, and monocyte activation. T-tests, χ tests, and propensity score matching analyses were used to compare markers by HIV status, and multiple linear regressions were used to assess associations of arginine metabolites with markers of inflammation. RESULTS: Overall, 131 participants were enrolled (93 HIV-infected and 38 HIV-uninfected controls); 70% were men; 58% African-Americans; median age was 51 years, median absolute CD4 was 735 cell/mm. Lysine, arginine, citrulline, global arginine bioavailability ratio, and symmetrical dimethylarginine were different between HIV-infected and HIV-uninfected adults (P = ≤0.02), but asymmetric dimethylarginine was not (P ≥ 0.13). Arginine biomarkers in HIV-infected, but not in HIV-uninfected controls, were associated with all measured markers of inflammation, endothelial activation, and coagulation (P ≤ 0.05). CONCLUSION: HIV-infected participants on antiretroviral therapy with virologic suppression have altered plasma levels of biomarkers in the arginine pathway compared with controls. These biomarkers are independently associated with markers of inflammation and monocyte activation in HIV.

Effect of statin on arginine metabolites in treated HIV-infection.

BACKGROUND AND AIMS: Asymmetric dimethylarginine (ADMA) is an inhibitor of nitric oxide and an independent risk factor for cardiovascular disease. We examined the effect of statin on ADMA in HIV + patients on stable ART, and whether such an effect contributes to the favorable changes on carotid intima media thickness. METHODS: This is a secondary analysis of SATURN-HIV, in which HIV + adults on stable ART with HIV-1 RNA< 1000 copies/mL and LDL-cholesterol <130 mg/dL were randomized to 10 mg daily rosuvastatin or placebo. Arginine metabolites, ADMA, and markers of inflammation were assessed at baseline and 48 weeks. Carotid intima media thickness (c-IMT) was measured at baseline, 48 and 96 weeks. Spearman correlations, and linear mixed-effect models were used to study relationships among variables. RESULTS: Overall, 79% were male, 68% African Americans, with a median age of 46 years. In the statin arm, no change in ADMA levels was observed at 48 weeks (0.70%), whereas a trend towards an increase in ADMA levels (23.78%) was observed in the placebo group (p = 0.06). Elevated baseline ADMA (highest tertile) was associated with a 0.04 mm increase in c-IMT (p = 0.03) after adjusting for statin and study duration. No interaction was seen between baseline ADMA and statin randomization on change in c-IMT (p = 0.21). CONCLUSIONS: In HIV + subjects on ART, rosuvastatin suppressed the increase over time in ADMA levels. Elevated baseline levels of ADMA were associated with increases in c-IMT, regardless of statin assignment. The favorable effect of rosuvastatin on c-IMT appears to be independent of the arginine pathway.