Comparing Blood Vessel Endothelial Function in HIV-Infected People and Matched HIV-Uninfected People

Inclusion Criteria for HIV-Infected Group: * Positive HIV enzyme-linked immunosorbent assay (ELISA) test with confirmatory Western Blot * Not currently receiving antiretroviral therapy Inclusion Criteria for HIV-Uninfected Group: * Negative HIV ELISA test at screening * Within 10 years of age of the matched HIV-infected participant * Same sex and current smoking status as the matched HIV-infected participant * Height within 4 inches of the matched HIV-infected participant Exclusion Criteria for All Participants: * Inability to complete written informed consent * Incarceration at the time of screening or main study visit * Diagnosed vascular disease (e.g., history of angina pectoris, coronary disease, peripheral vascular disease, cerebrovascular disease, aortic aneurysm, or otherwise known atherosclerotic disease) * Diagnosed disease or process associated with increased systemic inflammation (e.g., systemic lupus erythematosis, inflammatory bowel diseases, or other collagen vascular diseases); Note: Hepatitis B or C co-infections are not exclusionary * History of bleeding diathesis, gastrointestinal ulceration or bleeding, cerebrovascular aneurysm or bleeding, or retinal hemorrhage * Known or suspected cancer requiring systemic treatment within 6 months of screening * History of diabetes mellitus, as defined by the American Diabetes Association; Note: History of gestational diabetes is not exclusionary * History of migraine headaches * History of Raynaud's phenomenon * History of cardiac arrhythmias or cardiomyopathy * History of hypothyroidism or hyperthyroidism, even if treated; Note: Use of caffeinated products, except on the mornings of the study visits, is not exclusionary * Known allergy or intolerance to nitroglycerin * History of carotid bruits * Creatinine clearance less than 50mL/min, using a serum creatinine level measured at screening * Hemoglobin level greater than 9.0g/dL at screening * Alanine aminotransferase (ALT) level or aspartate aminotransferase (AST) greater than three times the upper limit of normal (ULN) at screening * Total bilirubin greater than 2.5 times ULN at screening * Fever, defined as a temperature greater than 38.0 C within 48 hours prior to screening * Received therapy for acute infection or other serious medical illness within 14 days prior to screening * Pregnant or breastfeeding during the course of the study * Hypotension, defined as systolic blood pressure less than 90mm Hg, at screening. * Uncontrolled hypertension * Receipt of anti-inflammatory agents (e.g., plaquenil, infliximab, etanercept, mycophenolate mofetil, sirolimus, tacrolimus, cyclosporine, pentoxifylline, thalidomide) * Receipt of investigational agents, cytotoxic chemotherapy, systemic or topical glucocorticoids (of any dose), or anabolic steroids within 28 days of screening; Note: Physiologic testosterone replacement therapy is not exclusionary * Receipt of lipid-lowering drugs, aspirin, other non-steroidal anti-inflammatory drugs (NSAIDs), acetazolamide, anticoagulants, anticonvulsants, or thyroid replacements within 7 days prior to screening * Use of sildenafil, vardenafil, or tadalafil within 72 hours (before or after) of each main study visit * Active drug or alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements