Biomarkers for Muscle Function and Aging in Chronic HIV Infection

Inclusion Criteria: Group 1: HIV positive subjects * HIV positive * English speaking * 50-65 years old * On Antiretroviral therapy and an HIV viral load below 200 copies/ml * CD4 equal to or greater than 350 cells/mm3 * Postmenopausal (women) * Lower extremity mobility sufficient to participate in functional assessment. Group 2: HIV negative subjects Inclusion Criteria for Group 2 subjects * English speaking * 50-65 years old * Negative for HIV (based on an HIV antibody test at Study Visit 1) * Matched to Group 1 for sex (50% W, 50% M) and age (50 - 65yo) * Postmenopausal (women) * Lower extremity mobility sufficient to participate in functional assessment. Exclusion Criteria: Exclusion Criteria for Group 1 Subjects * Acute or serious illness within 60 days prior to entry * Use of pharmacologic doses of corticosteroids in the past 6 months. * Use of anabolic therapy in the past 6 months. * Lower extremity mobility insufficient to participate in functional assessment. * Current use (last 30 days) of anticoagulants or known bleeding disorder. Exclusion Criteria for Group 2 subjects * Acute or serious illness within 60 days prior to entry * Use of pharmacologic doses of corticosteroids in the past 6 months * Use of anabolic therapy in the past 6 months * Lower extremity mobility insufficient to participate in functional assessment * Current use (last 30 days) of anticoagulants or known bleeding disorder.