Oxidant stress & ascorbic acid processing in diabetes

项目二：糖尿病中的氧化应激和抗坏血酸处理该项目的目的是研究氧化应激和羰基应激在糖尿病并发症发病机制中的作用。特别是，该项目（项目2）试图测试的假设，即在组织培养和糖尿病大鼠中的高葡萄糖导致的氧化应激，与糖尿病的人，主要是过渡金属和醛糖还原酶依赖。此外，我们假设许多药物被认为是作为醛糖还原酶抑制剂，抗糖化剂，生长因子，NO合酶，PKC和其他抑制剂在大鼠中作为过渡金属螯合剂和/或抗氧化剂具有有益的效果。我们建议通过使用非常强大的探针来评估体内氧化应激，即6-脱氧-6-氟抗坏血酸（F-抗坏血酸）结合750 MHz 19 F-NMR光谱来测试这些假设，而同时提供了对体内抗坏血酸催化剂及其糖尿病调节的第一个生物化学见解。1. 目的：研究低、高糖环境下抗坏血酸降解产物的化学性质和形成机制。第二章：确定高糖环境如何影响糖尿病并发症相关细胞中F-抗坏血酸降解的代谢途径。确定大鼠和人类的糖尿病如何影响抗坏血酸处理，以及未发现的异常是否可预测大鼠和DCCT患者的糖尿病并发症的发展。使用这种新的方法，我们希望澄清关键问题：为什么大量的药物在糖尿病大鼠中取得了成功，但在人类中却失败了，这是由于糖尿病大鼠特有的氧化应激的正常化，并且这种压倒性的强度掩盖了糖尿病引起的人类并发症的其他机制。如果得到证实，这一结果将对基于高血糖大鼠模型的抗糖尿病治疗的未来发展产生深远影响。

Project #2: OXIDANT STRESS AND ASCORBIC ACID PROCESSING IN DIABETES The objective of the Program Project is to investigate the role of oxidative and carbonyl stress in the pathogenesis of diabetic complications. In particular, this project (Project 2) seeks to test the hypothesis that the oxidative stress resulting from high glucose in tissue culture and the diabetic rat is, in contrast to the diabetic human, primarily transition metal and aldose reductase dependent. Furthermore, we hypothesize many of the drugs thought to act as aldose reductase inhibitors, anti-glycating agents, growth factors, NO synthase, PKC and other inhibitors have beneficial effects in the rat as transition metal chelators and/or antioxidants. We propose to test these hypotheses by using a very powerful probe for assessment of oxidative stress in vivo, i.e 6-deoxy-6- fluoro ascorbic acid (F-ascorbate) in conjunction with 750 MHz 19F- NMR-spectroscopy, while at the same time providing the first biochemical insight into ascorbate catabolism in vivo and its modulation by diabetes. 1. To determine the chemical nature and mechanism of formation of F- ascorbate degradation products formed in vitro in low and high glucose environment. 2: To determine how the metabolic pathways of F-ascorbate degradation in cells implicated in diabetic complications are influenced by high glucose environment, and 3. To determine how diabetes in the rat and the human affects ascorbate processing, and whether uncovered abnormalities predict development of diabetic complications in the rat and DCCT patient. Using this novel approach, we expect to clarify the critical question: Is the reason why a large number of drugs have been successful in the diabetic rat but have failed in the human due to normalization of oxidative stress that is specific to the diabetic rat and of such overwhelming intensity that it masks other mechanisms of diabetes induced complications in the human. If confirmed, this outcome would have a profound effect on the future development of anti-diabetic therapies based on the rat model of hyperglycemia.