Factors Mediating Gut Microbiota Dysbiosis and Metabolic Disease in HIV Patients.

Inclusion Criteria: * Men and women; 18 years to 65 years (All Cohorts) * Subjects with chronic HIV-1 Infection defined as a positive ELISA confirmed by a positive Western Blot or plasma HIV-1 RNA level \>1,000 copies/mL at any time in the past. (Cohorts A1, A2 \& A3) * HIV-1 seronegative (Cohort A4) * Either with or without lipodystrophy (to be assessed at Visit 1) * Body mass index (BMI) between 21-29 mg/kg2 and weight stable for at least 3 months (All Cohorts) * Antiretroviral therapy (ART) naïve (Cohort A3): \<10 days of ART treatment at any time prior to Visit 1 or previously on ART but off treatment for the previous 6 months prior to Visit 1 * Long-term ART (Cohort A1 \& A2): Must be on same antiretroviral treatment and have a plasma HIV-1 RNA \<25 copies/mL for 3-6 months prior to Visit 1.Liver function tests not greater than 2x normal, normal kidney and thyroid function. Fasting glucose must be \<110 mg/dl * Liver function tests not greater than 2x normal, normal kidney and thyroid function. Fasting glucose must be \<110 mg/dl * ART-treated individuals whose microbiota resembles those with untreated HIV infection and ART-treated individuals whose microbiota resembles the HIV-negative control cohort (equal numbers with and without lipodystrophy).(Cohort B; a subset of Cohort A) Exclusion Criteria: * Gastrointestinal disease such as inflammatory bowel disease, Clostridium difficile colitis or celiac sprue. * history of bowel resection, bleeding disorder, history of hyperglycemia, treated with high-dose glucocorticoid therapy or alpha-interferon in past year Current use of anticoagulant therapy * Daily use of aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) with inability to withhold drug for 7 days before and after a rectosigmoid biopsy procedure. * Used antibiotics within the prior three months * Pregnancy * Current use of proton pump inhibitors and H2-blockers * Active opportunistic or other chronic infection, such as hepatitis B or C or an active malignancy * Patient inability to participate in the study, such as inability to undergo venipuncture, completion of questionnaire or mucosal biopsy (if selected) procedures that form part of the inclusion/exclusion criteria or part of the outcome measure.