Tenofovir (TFV), efavirenz (EFV) and ritonavir (RTV) are the first line highly active antiretroviral therapy (HAART) agents used in most treatment of HIV patients. Their uses are well documented to be associated with increased cardiovascular dysfunction and co-morbid toxicity, but the potential beneficial effect of Mg- supplementation has not been investigated. Several protease inhibitors (PI), RTV in particular, and EFV can cause elevated endothelial cell reactive oxygen species generation and cellular dysfunction. Dyslipidemia associated with PI use may also account for increased risk of myocardial infarction. Most NRTIs, TVF included, display varying degrees of mitochondrial toxicity. Our in vitro studies using cultured endothelial cells indicate that high extracellular Mg attenuated AZT-induced increases in ROS formation, decreased release of PGI2 and NO and reduced cell viability. Similar effects were observed for RTV-induced cytotoxicity. AZT treatment in a rat model provoked systemic oxidative stress, neutrophil activation and inflammatory WBC infiltration of cardiac tissue;most intriguingly, all these oxidative indices were suppressed by dietary Mg supplementation. Based on the reported findings and our own observations, we postulate that: (i) prooxidant properties of most HAARTs may directly or indirectly cause endothelial injury and related metabolic disturbance leading to cardiac dysfunction;and (ii) Mg-supplementation provides systemic and cardioprotective benefits due to its modulating role against HAART-induced oxidative toxicity.
The specific aims are: 1) Establish the dose- and time- dependent systemic oxidative stress and cardiac pathogenesis and progression of dysfunction resulting from TFV, EFV, or RTV treatment in rats. 2) Determine if dietary Mg-supplementation attenuates each HAART- induced systemic pathogenesis and cardiac dysfunction through an anti-oxidative mechanism. 3) Determine the cytotoxic mechanisms of each HAART treatment in cultured endothelial cell (EC);assess the contribution of iron and inflammatory cytokines, and the protection afforded by high levels of Mg. Oxidative stress will be determined biochemically by lipid peroxidation products (8-isoprostane, lipid hydroperoxides), blood and tissue glutathione status and NO release. HAART-induced metabolic effects will be assessed (glucose intolerance, plasma lipid disturbances), and immunohistochemical and pathology techniques will be used to localize inflammatory markers and WBC infiltration. Alteration in iCAM and eNOS expression will be assessed by western blot analysis. Changes in cardiac function will be determined in situ by echocardiogram. This proposed exploratory study may reveal a potential usefulness of Mg-supplement as an effective, yet inexpensive adjunct therapy to minimize the deleterious impact of HAART-related cardiovascular oxidative and metabolic side effects.
The use of highly active antiretroviral therapy (HAART) agents for HIV-1 patients may cause adverse cardiovascular side effects. The proposed project will help to determine the cytotoxicity and cardiac functional impairment caused by three currently recommended HAART agents (tenofovir, efavirenz and ritonavir), and the potential beneficial effects of Mg-supplementation.
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