Cardioprotective Efficacy ofMg-Supplementation during HAART Therapy

描述（由申请人提供）：替诺福韦（TFV），依非韦伦（EFV）和利托那韦（RTV）是用于大多数HIV患者治疗的一线高效抗逆转录病毒疗法（HAART）药物。它们的使用与增加心血管功能障碍和合并症毒性有关，但补充镁的潜在有益作用尚未被调查。几种蛋白酶抑制剂（PI），特别是RTV和EFV可引起内皮细胞活性氧生成升高和细胞功能障碍。与使用PI相关的血脂异常也可能是心肌梗死风险增加的原因。大多数nrti，包括TVF，都表现出不同程度的线粒体毒性。我们使用体外培养的内皮细胞进行的研究表明，高细胞外Mg可减弱azt诱导的ROS形成增加、PGI2和NO释放减少以及细胞活力降低。rtv诱导的细胞毒性也有类似的效果。AZT在大鼠模型中引起全身氧化应激、中性粒细胞活化和炎症性白细胞浸润；最有趣的是，所有这些氧化指标都被膳食中添加Mg所抑制。根据已有的研究结果和我们自己的观察，我们假设：(i)大多数HAARTs的促氧化特性可能直接或间接导致内皮损伤和相关的代谢紊乱，从而导致心功能障碍；（ii）镁补充剂由于其对haart诱导的氧化毒性的调节作用而提供全身和心脏保护益处。具体目的是：1)建立剂量和时间依赖性的大鼠全身氧化应激和心脏功能障碍的发病机制和进展，由TFV、EFV或RTV治疗引起。2)确定膳食补充镁是否通过抗氧化机制减弱HAART诱导的各种全身发病机制和心功能障碍。3)确定每种HAART治疗对培养内皮细胞（EC）的细胞毒性机制；评估铁和炎性细胞因子的贡献，以及高水平镁所提供的保护。氧化应激将通过脂质过氧化产物（8-异前列腺素、脂质氢过氧化物）、血液和组织谷胱甘肽状态和NO释放来确定。将评估haart诱导的代谢影响（葡萄糖耐受不良，血脂紊乱），免疫组织化学和病理技术将用于定位炎症标志物和白细胞浸润。western blot检测iCAM和eNOS表达的变化。心功能的变化将通过超声心动图原位测定。这项探索性研究可能会揭示镁补充剂作为一种有效且廉价的辅助治疗的潜在用途，以最大限度地减少haart相关心血管氧化和代谢副作用的有害影响。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: 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.