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[Lipids and AIDS]
Insights
HIV infection alters lipid levels, increasing triglycerides and decreasing HDL, correlating with disease severity. This dyslipidemia, potentially linked to antiretroviral drugs, elevates cardiovascular risk in patients.
Area of Science:
- Biochemistry
- Immunology
- Pharmacology
Context:
- HIV infection significantly impacts lipid metabolism.
- Antiretroviral therapies, particularly protease inhibitors, are associated with lipodystrophy and metabolic syndrome.
- Cytokines released during HIV infection may contribute to dyslipidemia.
Purpose:
- To elucidate the mechanisms of dyslipidemia in HIV-infected individuals.
- To explore the link between HIV, antiretroviral drugs, and metabolic complications.
- To assess the cardiovascular risk associated with HIV-induced dyslipidemia.
Summary:
- HIV infection causes early cholesterol decrease and later triglyceride increase, with reduced HDL, proportional to CD4 count decline.
- Mechanisms include increased TG synthesis, decreased TG catabolism, reduced lipoprotein lipase activity, and enhanced LDL catabolism.
- Antiprotease drugs can induce lipodystrophy, central obesity, insulin resistance, and cushingoid features, increasing cardiovascular risk.
Impact:
- Highlights the significant cardiovascular risk in HIV patients due to dyslipidemia.
- Emphasizes the need to understand the pathogenesis of these metabolic complications.
- Suggests that managing dyslipidemia in HIV patients requires strategies similar to non-infected individuals, while seeking safer antiretroviral agents.
Abstract:
HIV infection induces an early decrease of cholesterol and a late increase of triglycerides (TG) with a reduction of HDL. These changes are proportional with the lowering of CD4, which reflects the infection's severity. Both the increase of TG synthesis and the decrease of TG catabolism, in relation with a reduction of lipoprotein lipase activity, are responsible of these changes. Moreover, LDL catabolism is enhanced by macrophage scavenger receptors, due to a high proportion of small, dense LDL which are more easily oxidized. Many cytokines (interferon alpha, interleukins, TNF) play probably a pathogenic role in the dyslipidemia. Some HIV patients who received antiproteases may develop lipodystrophy with central obesity, insulino-resistance, glucose intolerance and sometimes diabetes (like in syndrome X). Other patients present a cushingoid, buffalo hump. This complication may be observed also with antiretroviral treatment other than antiproteases. The physiopathology of these findings could be in relation with structural homologies between antiproteases and some important proteins, involved in lipid and adipocyte metabolism. Cardiovascular risk linked to these perturbations is evident. The treatment is not different from the treatment for seronegative, hyperlipidemic patients: struggle against risk factors, diet advices, fibrates or statins. The antiproteases bring huge contribution to the prognosis of AIDS patients but the risk of cardiovascular complications could impair this therapeutic progress. So, it is essential to understand the pathogeny of these complications in order to discover new antiproteases, without these adverse side effects.