Diabetic Neuropathy: Implications for Wound Repair

描述（由申请人提供）： 该提议探讨了皮肤感觉神经纤维和内皮细胞之间发生的响应皮肤损伤的细胞信号传导途径。我们以前的数据表明，神经源性神经肽有助于正常的伤口修复过程。相反，与糖尿病相关的非愈合性慢性溃疡的特征在于微血管病变和神经支配减少。基于过去资助期间令人鼓舞的数据，我们继续探索我们的假设，即在糖尿病患者中，高血糖和高脂血症损害微血管内皮细胞对神经源性神经肽的反应和内皮细胞产生必要的炎症介质。这些异常导致对皮肤损伤的反应受损。我们将测试我们的假设，解决以下目标：目标1：确定高血糖和基质糖基化对微血管内皮细胞反应的影响。高脂血症可直接改变细胞反应，并可通过细胞外基质分子糖基化间接改变细胞反应。我们将确定高血糖和/或基质分子糖基化是否改变SP诱导的内皮细胞介质合成，细胞骨架组织，整合素表达和细胞内信号传导。目的2：确定升高的脂肪酸水平对内皮细胞反应的影响。高血压与糖尿病并发症密切相关。我们将确定是否升高的脂肪酸单独或作为甘油三酯改变SP诱导的内皮细胞介质合成，细胞骨架组织，整合素表达或细胞内信号。目的3：探讨高血糖、高血脂对微血管内皮细胞的抗氧化调节作用。高脂血症引起的氧化应激可改变细胞对损伤的反应。我们将继续研究抗氧化剂、维生素E、维生素C和N-乙酰半胱氨酸对高血糖和高血脂条件下细胞反应的影响。目的4：确定神经肽活性的恢复是否改善糖尿病小鼠的伤口修复。我们将使用几种方法来评估神经肽在创伤修复中的作用。在高血糖db/db小鼠中使用切除伤口修复模型，我们将替换P物质并抑制中性内肽酶活性。我们还将测试抗氧化剂在这种小鼠伤口模型中的作用。

DESCRIPTION (provided by applicant): This proposal explores cell signaling pathways that occur between cutaneous sensory nerve fibers and endothelial cells in response to cutaneous injury. Our previous data suggest that nerve-derived neuropeptides contribute to the normal wound repair process. In contrast, non-healing chronic ulcers associated with diabetes mellitus are characterized by microangiopathy and decreased innervations. Based on encouraging data during the past funding period we continue to explore our hypothesis that in patients with diabetes mellitus, hyperglycemia and hyperlipidemia impair microvascular endothelial cell response to nerve-derived neuropeptides and endothelial cell production of necessary inflammatory mediators. These abnormalities contribute to impaired response to cutaneous injury. We will test our hypothesis by addressing the following Aims: Aim 1: To determine the effects of hyperglycemia and matrix glycosylation on microvascular endothelial cells responses. Hyperglycemia can directly alter cellular responses and can indirectly alter cellular response by extracellular matrix molecule glycosylation. We will determine whether hyperglycemia and/or matrix molecule glycosylation alters SP-induced endothelial cell mediator synthesis, cytoskeleton organization, integrin expression and intracellular signaling. Aim 2: To determine the effect of elevated fatty acid levels on endothelial cell responses. Hyperlipidemia is strongly associated with complications in diabetes mellitus. We will determine whether elevated fatty acids alone or as Triglycerides alter SP-induced endothelial cell mediator synthesis, cytoskeleton organization, integrin expression or intracellular signaling. Aim 3: To determine the anti-oxidant regulation of microvascular endothelial cell response to hyperglycemia & hyperlipidemia. Oxidative stress due to hyperlipidemia may alter cellular response to injury. We will continue our studies of effects of antioxidants, vitamin E, vitamin C and n-acetyl cysteine on cellular responses under hyperlipidemic and hyperglycemic conditions. Aim 4: To determine whether restoration of neuropeptide activity improves wound repair in diabetic mice. We will use several approaches to evaluate the roles of neuropeptides in wound repair. Using an excisional wound repair model in hyperglycemic db/db mice, we will replace substance P and inhibit neutral endopeptidases activity. We will also test the effects of antioxidants in this murine wound model.