Effect of highly active antiretroviral therapy on homocysteine plasma concentrations in HIV-1-infected patients.

Objective: To analyze the effect of antiretroviral therapy on homocysteine levels in HIV-1-infected patients.

Design: Observational, prospective study of patients with AIDS.

Methods: We included patients with HIV-1 infection naive for antiretroviral drugs. Before and after 6 months of treatment, we evaluated fasting and postoral methionine load plasma homocysteine, serum vitamins B6 and B12, and intraerythrocyte folate levels.

Results: We studied 69 patients who began therapy for a 6-month period. Fasting and postoral methionine load plasma homocysteine levels increased significantly after 6 months of antiretroviral therapy with respect to basal values (P < 0.001). Fasting hyperhomocysteinemia was present in 7.3% of patients before treatment and in 89.9% after 6 months of therapy (P = 0.0001). Postoral methionine load hyperhomocysteinemia was found in 4.5% of subjects before therapy vs. 98.5% at the end of study period (P = 0.001). These results were not associated with folate or vitamins B6 or B12 levels.

Conclusions: In patients with HIV-1 infection, fasting and postoral methionine load plasma homocysteine levels increased after 6 months of antiretroviral treatment. Nutritional abnormalities were not responsible for hyperhomocysteinemia, suggesting that enzymatic disturbances in the metabolic pathways of homocysteine may occur.