NO/STEM CELLS IN THE DIABETIC HEART

糖尿病心脏中的无细胞/干细胞

• 批准号: 7023880
• 负责人: Thomas H HINTZE
• 金额: $ 41.13万
• 依托单位: NEW YORK MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7023880
• 关键词: anions; biological signal transduction; cardiovascular disorder therapy; coronary disorder; diabetic cardiomyopathy; dogs; enzyme activity; heart function; heart metabolism; hematopoietic growth factor; hematopoietic stem cells; immunocytochemistry; insulin dependent diabetes mellitus; laboratory rat; myocardial ischemia /hypoxia; nitric oxide; nitric oxide synthase; noninsulin dependent diabetes mellitus; phosphorylation; protein metabolism; superoxides; vasodilation; western blottings

DESCRIPTION (provided by applicant): Diabetes is associated with both coronary vascular disease and cardiac ischemia resulting in accelerated and aggressive cardiac disease. In the previous 3 years we have focused on the potential role of reduced NO production on the diabetic heart. We have found that alloxane induced type I diabetes is characterized by increased mRNA for eNOS but reduced protein and NO production. We have also shown that there are marked shifts in cardiac substrate use, consistent with the role of NO in the control of cardiac fatty acid and glucose uptake. We have also found that the decrease in NO production results in altered regulation of myocardial oxygen consumption by NO perhaps contributing to a mismatch between oxygen delivery and demand. In the current application we will continue to focus on the role of NO in the control of cardiac function and metabolism. In specific aim 1, we will examine the potential that phosphorylation can increase the activity of eNOS and compensate for the reduction in eNOS protein which we observed in the diabetic heart. In vitro studies will be used to sort out the signaling mechanism and the Bezold-Jarisch reflex coronary dilation will be used as method to study this in vivo. Previously we have found that diabetes shifts substrate uptake in the heart from fatty acids to keto acids with no glucose uptake despite the marked increase in plasma glucose. We have also found that these shifts occur at about the time that NO production by the heart falls. We will investigate the relationship between NO production and substrate use in the diabetic heart in specific aim 2 of this proposal. Whereas most of our studies have focused on type 1 diabetes, the incidence of type II diabetes is increasing in the population at epidemic rates. To investigate the role of altered NO production and the mechanism responsible we have begun studies in the Zucker fatty rat (Type II) and to contrast those findings with rats treated with Streptozotocin (Type I) or alloxan. Interestingly, and the focus of specific aim 3 we have found that eNOS protein is normal in the heart of the Zucker rat accompanied by a reduction in NO bioactivity (unlike the Strep treated rat where eNOS protein is reduced by 50%). These data imply an important role for superoxide anion in Type II diabetes and will be the focus of this specific aim. In specific aim 4 we will determine whether treatment of the diabetic dog heart with growth factors to recruit cardiac stem cells results in alterations in cardiac function after infarction. Because diabetes is characterized by aggressive myocardial ischemia we postulate that in the diabetic heart compensatory mechanisms such as stem cell recruitment are deficient resulting in exaggerated ischemia. Thus this proposal will continue work on the role of NO in the control of cardiac function and metabolism and extend these studies to the role of cardiac stem cells in the genesis and treatment of the diabetic ischemic heart.

描述（由申请人提供）：糖尿病与冠状血管疾病和心肌缺血有关，导致加速和侵袭性心脏病。在过去的 3 年里，我们一直关注减少 NO 产生对糖尿病心脏的潜在作用。我们发现四氧烷诱发的 I 型糖尿病的特点是 eNOS mRNA 增加，但蛋白质和 NO 产生减少。我们还表明，心脏底物的使用发生了显着变化，这与 NO 在控制心脏脂肪酸和葡萄糖摄取中的作用一致。我们还发现，NO 产生的减少会导致 NO 对心肌耗氧量的调节发生改变，这可能会导致氧气输送和需求之间的不匹配。在当前的应用中，我们将继续关注NO在控制心脏功能和代谢中的作用。在具体目标 1 中，我们将研究磷酸化可以增加 eNOS 活性并补偿我们在糖尿病心脏中观察到的 eNOS 蛋白减少的潜力。体外研究将用于理清信号传导机制，并且 Bezold-Jarisch 反射冠状动脉扩张将用作体内研究的方法。此前我们发现，糖尿病将心脏中的底物摄取从脂肪酸转变为酮酸，尽管血浆葡萄糖显着增加，但没有葡萄糖摄取。我们还发现，这些变化大约发生在心脏一氧化氮生成量下降的时候。我们将在本提案的具体目标 2 中研究糖尿病心脏中 NO 产生和底物使用之间的关系。尽管我们的大部分研究都集中在 1 型糖尿病上，但 II 型糖尿病的发病率在人群中呈流行趋势。为了研究 NO 产生改变的作用及其机制，我们开始在 Zucker 脂肪大鼠（II 型）中进行研究，并将这些结果与链脲佐菌素（I 型）或四氧嘧啶治疗的大鼠进行对比。有趣的是，在具体目标 3 的重点中，我们发现 Zucker 大鼠心脏中的 eNOS 蛋白是正常的，同时伴随着 NO 生物活性的降低（与 Strep 治疗的大鼠不同，其中 eNOS 蛋白减少了 50%）。这些数据表明超氧阴离子在 II 型糖尿病中发挥着重要作用，并将成为这一具体目标的重点。在具体目标 4 中，我们将确定用生长因子招募心脏干细胞治疗糖尿病狗心脏是否会导致梗塞后心脏功能的改变。由于糖尿病的特点是严重的心肌缺血，我们假设糖尿病心脏中干细胞募集等代偿机制存在缺陷，导致过度缺血。因此，该提案将继续研究NO在控制心脏功能和代谢中的作用，并将这些研究扩展到心脏干细胞在糖尿病缺血性心脏的发生和治疗中的作用。