Conditions: HIV
Keywords: Endothelial function
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 60
Healthy volunteers: no

Brief summary:
The investigators hypothesize that older subjects with HIV randomly assigned to atazanavir will have increased bilirubin levels, reduced oxidative stress, and improved flow-mediated, endothelium-dependent vasodilation compared to subjects not switched to atazanavir.

Detailed description:
The mortality induced by HIV has dropped significantly due to effective antiretroviral therapy. Epidemiological data suggest a less than 5% 10-year mortality for patients treated with HAART. As a result of the reduction in early AIDS-related deaths, HIV has become a chronic disease manifesting the common components of chronic disease such as inflammation, vascular dysfunction, and oxidative stress. The combination of these trends put HIV patients at increased risk of myocardial infarction compared with age-matched subjects over the long term. Several studies suggest that some protease inhibitors might increase the risk of myocardial infarction. The leading theory behind this association derives from the relationship between protease inhibitor use and the onset of an atherogenic dysmetabolism including the development of insulin resistance, dyslipidemia, and oxidative stress.

In contrast to the older protease inhibitors, atazanavir induces neither insulin resistance nor dyslipidemia. In addition, atazanavir has a property unique among protease inhibitors: elevation of unconjugated bilirubin by inhibiting the enzyme uridine diphosphate glucuronyltransferase (UGT) 1A1. Bilirubin is a potent intracellular antioxidant. The investigators have demonstrated that higher levels of bilirubin within the normal range are associated with reduced rates of stroke and peripheral artery disease. Patients with Gilbert's Syndrome (chronic elevations of bilirubin as a result of genetically reduced UGT 1A1) have a lower rate of myocardial infarction compared with age-matched controls. It is plausible that use of atazanavir compared with other protease inhibitors, by reducing oxidative stress, may improve vascular function and, ultimately, reduce the rate of cardiovascular complications with chronic therapy.

The benefit of atazanavir may be particularly important now with the aging of the HIV population. Aging is associated with higher levels of oxidative stress and endothelial dysfunction, both of which are associated with heightened rates of cardiovascular morbidity and mortality. Accordingly, the investigators hypothesize that the use of atazanavir in stable HIV patients age 45 years or older will improve endothelial dysfunction and reduce oxidative stress compared with continuing the current therapy.

Arms:
arm 1: Subjects are enrolled and either kept on their baseline regimen. This is being designated the placebo comparator. arm 2: These subjects are switched to an atazanavir-based regimen.

Interventions: intervention 1: Atazanavir intervention 2: Placebo
Intervention descriptions: intervention 1: The active group will switch from a non-atazanavir regimen to an atazanavir-based regimen. intervention 2: The control group will stay on their baseline regimen

Protocol document: