MECHANISMS OF CARDIOVASCULAR COMPLICATIONS IN AIDS

拟议研究的主要长期目标是调查艾滋病患者可卡因滥用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，分子机制尚未明确。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Tat蛋白可以改变细胞基因表达和信号转导途径，诱导TNFalpha和il -1 β等细胞因子的形成。初步数据表明，TNFalpha可以损害心血管功能，在可卡因的存在下，这种情况会加剧。因此，我们将通过研究以下具体目标来验证Tat和细胞因子（TNFalpha和IL-1 β）与可卡因及其代谢物的组合可以在艾滋病患者中产生心血管并发症的假设：(1)确定可卡因及其主要代谢物在TNFalpha或IL-1 β存在和不存在的情况下调节离体人类心肌细胞中Ca2+， Na+和K+电流的作用；(2)研究在存在或不存在可卡因的情况下Tat蛋白和/或炎症细胞因子对整合素表达和整合素介导的事件（即内皮细胞迁移和白细胞粘附内皮细胞）的调节作用；(3)通过监测以下方面的变化来评估急性或慢性可卡因和/或TNFalpha治疗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，(c)通过测量左心室压的变化和变化率来测量左心室收缩力；(4)确定Tat蛋白在调节心血管功能中的作用。转基因和TNFalpha受体敲除小鼠模型将用于测试特定目标#3所指示的各种参数。拟议的研究将提供一个深入的分子机制，可能负责在存在艾滋病毒感染的可卡因诱导心血管并发症。该提案的统一主题是确定Tat和炎性细胞因子在调节可卡因诱导的心脏毒性作用中的作用，这种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.