This is a prospective, non-randomised, 48 week study of the effect of protease inhibitor (PI) containing and non-PI containing antiretroviral regimens on the expression of adipocyte specific genes, protein levels and cellular structure in HIV-infected individuals, naive to therapy, who are starting therapy for the first time.

Antiretroviral medications, used to treat HIV infection, cause side effects. These include changes in composition of fat throughout the body (loss in some areas and accumulation in others), elevations in blood lipids and abnormalities in glucose metabolism. The resulting syndrome is known as "HIV associated lipodystrophy" or HIVLD. In HIV negative populations, such abnormalities in lipid and glucose metabolism are associated with an increased risk of developing cardiovascular disease (CVD). The aim of this study is to characterize the changes that occur in body composition and metabolism with antiretroviral treatment and compare them to changes in fat tissue structure and function and surrogate markers for cardiovascular disease.

Inclusion Criteria:

• Age >18.
• Be able to provide written consent to perform in the trial.
• HIV antibody positive at time of entry to the study.

Specific to HIV Infection and Metabolic Abnormalities Protocol 1 (HAMA) part A only:

• Be naive to antiretroviral medication.

Specific to HAMA part B only:

• Have had a minimum total exposure to antiretroviral medications (to include drugs from more than one drug class) of 48 weeks at time of recruitment.
• Have had a minimum of 48 weeks interval since completion of HAMA part A.

Exclusion Criteria:

• Any history of, or ongoing, mental or physical condition (including suspected or known diagnosis of ischaemic heart disease), which, in the opinion of the investigator, would impede the subject's ability to participate in the trial.
• Prior use of growth hormone or glucocorticoid or anabolic steroid products within the previous six months.
• Prior use of supraphysiological doses of testosterone or oestrogen replacement therapy within the previous year.
• Alcohol or substance abuse which in the opinion of the investigator would affect the patients ability to participate in the trial.
• Prior use of any retinoid-containing compound within the previous six months.
• Abnormal coagulation.
• Previous allergic reaction or known allergy to local anaesthetic.
• Previous or concomitant use of medications, which, in the opinion of the investigator, would affect the subject's ability to participate in all activities involved in the trial.
• Any grade-three laboratory abnormality recorded from screening bloods, which, in the opinion of the investigator, would impede the subject's ability to safely complete all study requirements.
• Any finding on screening clinical examination, which, in the opinion of the investigator, would impede the subject's ability to participate in the rest of the trial.
• Pregnancy

Specific to HAMA part A only:

• Prior use of anti-retroviral agents (including protease inhibitors, nucleoside or non-nucleoside reverse transcriptase inhibitors, investigational antiretroviral agents or fusion inhibitors). Entry of individuals who have had previous antiretroviral therapy as part of post exposure prophylaxis will be at the discretion of the study investigators.