MECHANISMS OF CARDIOVASCULAR COMPLICATIONS IN AIDS

这项研究的主要长期目标是调查艾滋病患者滥用可卡因导致心血管并发症的机制。可卡因滥用引起的严重心血管并发症是众所周知的，然而，分子机制尚未阐明。细胞因子在内皮细胞和心肌细胞功能的正常调节中起重要作用。越来越多的证据表明，HIV-1的达特蛋白可以改变细胞基因表达和信号转导途径，并可以诱导细胞因子如TNF α和IL-1 β的形成。初步数据表明，TNF α可损害心血管功能，在可卡因存在下加剧。因此，我们将检验达特和细胞因子的组合（TNF α和IL-1 β）与可卡因及其代谢物的联合使用可在艾滋病患者中产生心血管并发症，通过研究以下具体目标：（l）确定可卡因及其主要代谢物在调节Ca 2+中的作用，在存在和不存在TNF α或IL-1 β的情况下分离的人心肌细胞中的Na+和K+电流;（2）研究达特蛋白和/或炎性细胞因子在存在或不存在可卡因的情况下对整联蛋白表达和整联蛋白介导的事件的调节作用，也就是说，内皮细胞迁移和白细胞与内皮细胞的粘附;（3）通过监测以下方面的变化来评估用可卡因和/或TNF α急性或慢性治疗的小鼠的心血管并发症：（a）通过全身动脉压和心输出量测量的全身血管阻力，（B）通过监测肺动脉压和心输出量确定的肺血管阻力，和（c）通过测量左心室压力的变化和变化率来测定左心室收缩力;和（4）确定达特蛋白在调节心血管功能中的作用。达特转基因和TNF α受体敲除小鼠模型将用于检测特定目标#3下所示的各种参数。拟议的研究将提供一个深入了解的分子机制，可能是负责可卡因诱导的心血管并发症的存在下，艾滋病毒感染。该提案的统一主题是确定达特和炎症细胞因子在调节可卡因诱导的心脏毒性作用中的作用，这些作用已在艾滋病患者中观察到。

The primary long term goal of the proposed research is to investigate the mechanisms responsible for cardiovascular complications from cocaine abuse in AIDS patients. Serious cardiovascular complications due to cocaine abuse are well known; however, the molecular mechanisms have not been delineated. Cytokines play a significant role in the normal regulation of the function of endothelial cells and cardiac myocytes. There is growing evidence that the Tat protein of HIV- l can alter cellular gene expression and signal transduction pathways and can induce the formation of cytokines such as TNFalpha, and IL-1beta. Preliminary data demonstrate that TNFalpha can compromise cardiovascular function which is exacerbated in the presence of cocaine. We will therefore test the hypothesis that a combination of Tat and the cytokines (TNFalpha and IL- 1beta) with cocaine and its metabolites can produce cardiovascular complications in AIDS patients, by investigating the following specific aims: (l) to determine the effects of cocaine and its major metabolites in modulating the Ca2+, Na+ and K+ currents in isolated human cardiac myocytes in the presence and absence of TNFalpha or IL-1beta; (2) to investigate the modulatory effects of Tat protein and/or the inflammatory cytokines in the presence or absence of cocaine on integrin expression and integrin mediated events, i.e., endothelial cell migration and leucocyte adhesion to endothelial cells; (3) to assess the cardiovascular complications in mice acutely or chronically treated with cocaine and/or TNFalpha by monitoring the changes in: (a) systemic vascular resistance measured by systemic arterial pressure and cardiac output, (b) pulmonary vascular resistance determined by monitoring pulmonary arterial pressure and cardiac output, and (c) left ventricular contractility by measuring changes and the rate of change in the left ventricular pressure; and (4) to determine the role of Tat protein in modulating cardiovascular function. The tat transgenic and TNFalpha receptor knockout mouse models will be used to test the various parameters indicated under specific aim #3. The proposed studies will provide an in-depth understanding of the molecular mechanisms that may be responsible for the cocaine-induced cardiovascular complications in the presence of HIV infection. The unifying theme of the proposal is to define the role of Tat and the inflammatory cytokines in modulating the cocaine induced cardiotoxic effects that have been observed in patients with AIDS.