Integrative analysis of coronary adaptations to ischemia

本建议的目的是描述参与冠状动脉侧枝生长或非出芽血管生成的信号。我们的一般论点是侧枝生长严重依赖于特定生长因子及其受体的时间依赖性表达。缺血发作时：受炎症、缺氧和/或细胞氧化还原状态调节的血管生成因子（胰岛素样生长因子-1）的表达增加。b.这些血管生成因子受体的表达增加（VEGF的IGF-I和-II受体，flk-1和flt受体，VEGF的TGF受体，TGF受体I型和II型）。在足以改善闭塞区域缺血的侧支过程中：a.受剪切应力调节的血管生成因子（血小板衍生生长因子-b [PDGF- b]及其受体（PDGF- α和β受体）和内皮型一氧化氮合酶[eNOS]）的表达增加。B.与血管生成和/或细胞增殖相关的生长因子和受体的表达恢复到基线水平。在糖尿病动物模型中：冠状动脉侧枝的生长，作为对短暂的，反复发作的缺血的反应，受到损害。5. 缺血发作时，受缺氧、炎症和氧化还原状态调控的血管生成因子表达减少或缺失；然而，表达这些因子的受体。冠脉血管生成将诱导慢性仪器狗2分钟重复冠状动脉闭塞。血管生成将在几个不同的时间进行评估：1。早期的反应;2. 快速生长期；和3。维护阶段;和4。最后的生长阶段。除了接受重复缺血刺激的动物外，还将研究假对照组和车辆对照组。侧支电导将通过测量闭塞区域的心肌功能、侧支血流（放射性微球）和闭塞后反应性充血反应的减少来评估。与血管生成相关的丝裂原将从正常和缺血血管区域的心肌间质透析液中测定（细胞增殖，管形成，Western分析）。Northern分析和逆转录酶聚合酶链反应将用于评估心肌和脉管系统中特定转录物的表达。该方法整合了从分子水平到生理水平的一系列技术，将有助于全面了解与冠状动脉血管生成相关的信号以及糖尿病破坏冠状动脉侧枝循环生长的机制。

The goal of this proposal is to delineate the signals involved in coronary collateral growth or non-budding angiogenesis. Our general thesis is that collateral growth is critically dependent on the time-dependent expression of specific growth factors and their receptors. At the onset of ischemia: a expression of angiogenic factors (insulin-like growth factor-1 that are regulated by inflammation, hypoxia, and/or the cellular redox state is increased. b. expression of receptors for these angiogenic factors is increased (IGF-I and -II receptors, flk-1 and flt receptors for VEGF, TGF receptors for VEGF, TGF receptor Types I and II). 2. During collateralization sufficient to ameliorate ischemia in the occluded territory: a. expression of angiogenic factors regulated by shear stress (platelet derived growth factor-B [PDGF-B] and its receptors (PDGF- alpha and -beta receptor), and endothelial nitric oxide synthase [eNOS]) is increased. b. expression of growth factors and the receptors associated with angiogenesis and/or cellular proliferation returns to baseline. In an animal model of diabetes: 4. Coronary collateral growth, in response to brief, repetitive episodes of ischemia is impaired. 5. At the onset of ischemia, expression of the angiogenic factors regulated by hypoxia, inflammation, and the redox state is reduced or absent; whereas, receptors for these factors are expressed. Coronary angiogenesis will be induced in chronically-instrumented dogs by 2 minute repetitive coronary artery occlusions. Angiogenesis will be evaluated at several different times: 1. Early responses; 2. Rapid growth phase; and 3. Maintenance phase; and 4. Final growth phase. Sham and vehicle control groups will be studied in addition to the animals receiving the repetitive ischemic stimuli. Collateral conductance will be evaluated by measurements of myocardial function in the occluded territory, collateral flow (radioactive microspheres), and diminution of reactive hyperemic responses following the occlusions. Mitogens associated with angiogenesis will be assayed from myocardial interstitial dialysate of the normal and ischemic vascular regions (cell proliferation, tube formation, Western analysis). Northern analysis, and reverse transcriptase polymerase chain reaction will be used to evaluate expression of the specific transcripts in the myocardium and vasculature. This approach integrates a range of techniques from this molecular to physiological levels will facilitate a complete understanding the signals associated with coronary angiogenesis and the mechanisms by which diabetes abrogates the growth of the coronary collateral circulation.