The retinal microenvironment in diabetic retinopathy

糖尿病视网膜病变的视网膜微环境

• 批准号: 8316113
• 负责人: ROBERT A. LINSENMEIER
• 金额: $ 36.75万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8316113
• 关键词: Acidosis; Acute; Adult; Affect; Age; Animals; Blood Vessels; Blood capillaries; Blood flow; Carbonic Acid; Clinical; Complications of Diabetes Mellitus; Diabetes Mellitus; Diabetic Retinopathy; Disease; Disease Progression; Dropout; Endothelial Cells; Environmental Risk Factor; Event; Excision; Experimental Diabetes Mellitus; Extravasation; Felis catus; Functional disorder; Hyperglycemia; Hypoxia; Lead; Letters; Link; Long-Evans Rats; Measurement; Measures; Messenger RNA; Metabolism; Michigan; Microspheres; Molecular; Neonatal; Oxygen; Pathway interactions; Phase; Play; Proteins; Rattus; Regulation; Relative (related person); Retina; Retinal; Retinal Diseases; Rodent; Role; Signal Transduction; Streptozocin; Testing; Time; Tissues; Treatment Protocols; Tumor Tissue; Vascular Endothelial Growth Factors; Work; angiogenesis; capillary; carbonate dehydratase; diabetic; insight; insulin signaling; relating to nervous system; response; transcription factor; type I and type II diabetes

DESCRIPTION (provided by applicant): Diabetic retinopathy is one of the most common causes of retinal disease in adults. Many molecular and histological changes have been demonstrated, and it is now recognized that neural as well as vascular problems exist. The most important contributor to vascular dysfunction is the elevation of vascular endothelial growth factor (VEGF), which causes vascular leakage and angiogenesis. Unfortunately, we still do not know what underlies the increase in VEGF. Hypoxia and acidosis are both known regulators of VEGF, but the magnitude and time course of changes in retinal oxygen and pH are not known in diabetes. More information about these parameters will allow a better understanding of disease progression, and ultimately may lead to an understanding of pathways that can be targeted before VEGF causes damage. We will make intraretinal recordings of PO2 and pH in rats with streptozotocin (STZ)-induced diabetes, and in rats with acidosis in the absence of diabetes. To place these changes in the context of other events, we will also measure important vascular parameters (blood flow, leakage, molecular signals). SPECIFIC AIM 1: Oxygen in diabetic retinopathy. Retinal tissue hypoxia has been implicated in the increased VEGF that is found in both the background and proliferative phases of retinopathy. There is considerable indirect support for the existence of hypoxia in diabetic retinopathy, but very limited direct evidence. We will characterize intraretinal oxygenation in rats with up to 1 year of diabetes. Our hypothesis is that inner retinal PO2 will decrease over this time. We will also investigate changes in the regulation of retinal oxygen in diabetics. Our hypothesis is that changes in regulation of PO2 will be a more sensitive indicator of changes in the microenvironment and occur earlier than changes in baseline PO2. We found increased PO2 in the retina in an earlier study at 12 weeks of diabetes. Our hypothesis is that this was due to increased blood flow, which we will now investigate. SPECIFIC AIM 2: Acidosis in diabetic retinopathy. VEGF is regulated by acidosis in some tissues but the role of pH in controlling VEGF in the adult retina is unknown. We will characterize retinal pH in rats with up to 1 year of diabetes. Our hypothesis is that the inner retina will be more acidic than normal for at least a few months. We also hypothesize that molecular mechanisms come into play to reduce acidosis, such as increased carbonic anhydrase and acid removal mechanisms. These will be evaluated with mRNA and protein measurements. SPECIFIC AIM 3: Is retinal acidosis sufficient to upregulate VEGF? Finding that the diabetic retina is acidotic will open the possibility that it is one of the factors that regulates VEGF, but will not tell us whether it is important. Consequently, we will produce acidosis in the absence of diabetes, via carbonic anhydrase inhibition. We will first establish a treatment protocol that yields intraretinal pH values similar to diabetes, and then evaluate changes in VEGF and leakage. Our hypothesis is that acidosis alone will be sufficient to increase VEGF, produce molecular changes that underlie leakage, and cause leakage itself.

描述（由申请人提供）：糖尿病性视网膜病是成人视网膜疾病最常见的原因之一。已经证明了许多分子和组织学变化，现在已经认识到存在神经和血管问题。引起血管功能障碍的最重要的因素是血管内皮生长因子（VEGF）的升高，这会导致血管泄漏和血管生成。不幸的是，我们仍然不知道是什么是VEGF增加的基础。缺氧和酸中毒都是VEGF的已知调节剂，但是视网膜氧和pH的变化的大小和时间过程在糖尿病中尚不清楚。有关这些参数的更多信息将使人们更好地了解疾病的进展，最终可能会导致对可以在VEGF造成损害之前的途径的理解。我们将在患有链蛋白酶（STZ）诱导的糖尿病的大鼠中对PO2和pH的视网膜内记录，在没有糖尿病的情况下患有酸中毒的大鼠。为了将这些变化放在其他事件的背景下，我们还将测量重要的血管参数（血流，泄漏，分子信号）。特定目标1：糖尿病性视网膜病中的氧气。视网膜组织缺氧与视网膜病的背景和增殖阶段发现的VEGF有关。对于糖尿病性视网膜病中缺氧的存在，有相当大的间接支持，但直接证据非常有限。我们将表征最多1年糖尿病的大鼠的内部氧合。我们的假设是内部视网膜PO2将在这段时间内减少。我们还将研究糖尿病患者视网膜氧气调节的变化。我们的假设是，PO2调节的变化将是微环境变化的更敏感的指标，并且比基线PO2的变化更早。我们发现，在糖尿病12周的早期研究中，视网膜中的PO2增加了。我们的假设是，这是由于血流增加所致，我们现在将调查。特定目标2：糖尿病性视网膜病中的酸中毒。 VEGF受某些组织中的酸中毒调节，但是pH在控制成人视网膜中VEGF中的作用尚不清楚。我们将表征患有长达1年糖尿病的大鼠的视网膜pH值。我们的假设是，内部视网膜至少几个月将比正常情况更酸性。我们还假设分子机制可以减少酸中毒，例如增加的碳酸酐酶和酸去除机制。这些将通过mRNA和蛋白质测量进行评估。特定目标3：视网膜酸中毒足以上调VEGF？发现糖尿病性视网膜是酸性的，它将打开它是调节VEGF的因素之一，但不会告诉我们它是否重要。因此，我们将在没有糖尿病的情况下通过碳酸酐酶抑制产生酸中毒。我们将首先建立一种治疗方案，该方案产生类似于糖尿病的视网膜内pH值，然后评估VEGF和泄漏的变化。我们的假设是，仅酸中毒就足以增加VEGF，产生渗漏构成并引起泄漏本身的分子变化。