Resting energy expenditure and substrate oxidation in human immunodeficiency virus (HIV)-infected asymptomatic men: HIV affects host metabolism in the early asymptomatic stage

Abstract

To study the effect of persistent human immunodeficiency virus (HIV) infection on host metabolism, we performed indirect calorimetry in 11 asymptomatic HIV-infected patients (Centers for Disease Control group II or III) who were seropositive for > 1 y, but who still had normal numbers of circulating CD4⁺ T cells, and in 11 healthy control subjects of similar age and relative body composition. HIV-infected patients had 8% (P < 0.05) higher rates of resting energy expenditure than did control subjects. Fat-oxidation rates were significantly higher in the patients (x̄ ± SE: 2.90 ± 0.08 vs 2.19 ± 0.17 g · kg FFM⁻¹ · d⁻¹, patients vs control subjects, P < 0.01) whereas no significant differences in carbohydrate-oxidation rates between patients and control subjects were found. These alterations in metabolism were not associated with increased concentrations of catecholamines, Cortisol, or thyroid hormones. Mean concentrations of interleukin 6 in the patients were increased only twofold when compared with healthy control subjects. The results indicate that HIV infection affects host metabolism in the early asymptomatic stage, before CD4⁺ T cell numbers start to decline.