Inhibition of Neointimal Hyperplasia Following Vascular Surgery in Diabetes

描述(由申请人提供)： 在美国，动脉粥样硬化仍然是导致死亡和残疾的主要原因。目前治疗严重动脉粥样硬化的方法有很高的失败率，这是由于继发于新生内膜增生的再狭窄。一氧化氮(NO)是一种小的血管保护分子，可抑制新生内膜增生的发展。作为我们之前的VA Merit资助周期的一部分，我们开发了几种不同的基于NO的疗法，成功地减少了动物模型中的新生内膜增生。然而，许多退伍军人患有糖尿病(DM)，这是一种改变局部动脉对损伤的反应的疾病。事实上，由于侵袭性新生内膜增生，糖尿病患者在血管介入治疗后的预后更差。这让我们质疑无基础疗法在这些患者群体中是否有效。我们实验室产生的初步数据表明，在I型和II型糖尿病的动物模型中，基于NO的治疗方法具有显著不同的疗效。我们发现，在II型糖尿病啮齿动物模型中，NO更有效地抑制新生内膜增生，而在I型糖尿病啮齿动物模型中，NO完全无效。这些差异似乎与胰岛素水平有关。因此，考虑到糖尿病在患有严重动脉粥样硬化的退伍军人中很常见，而且这些患者最需要治疗以提高通畅率，因此进一步评估基于NO的疗法在这些疾病中的疗效至关重要。我们的假设是，NO介导的抑制新生内膜增殖是由胰岛素信号通路调节的。因此，本研究的具体目标是：具体目标1：研究胰岛素和葡萄糖对体外培养的血管平滑肌细胞(VSMC)、血管内皮细胞和外膜成纤维细胞中NO调节增殖、迁移、细胞死亡和氧自由基能力的影响。具体目的2：在胰岛素治疗和非胰岛素治疗的I型和II型糖尿病动物模型中，评价NO抑制体内新生内膜增殖的效果。具体目标3：明确胰岛素信号通路在血管系统中调节NO下游有益效应的机制。具体地说，丝裂原激活的蛋白激酶通路将通过获得和失去功能的策略来操纵。预防患者尤其是患有糖尿病等疾病的患者发生新的内膜增生，将对患者的护理产生重大影响。由于糖尿病患者对血管干预的需求增加，而且干预后的结果更差，因此这一人群将从改善结果的治疗中受益匪浅。这项建议中的研究是新颖的，因为还没有研究人员研究一氧化氮在I型或II型糖尿病中的作用。因此，这项提议产生的数据将对我们所知的无血管生物学做出重大贡献，并将导致开发创新的策略来预防糖尿病患者群体中的新生内膜增生。最终，通过更好地了解调控NO在血管系统中的下游有益影响的途径，可以为我们的患者开发更好的基于NO的疗法，从而最大限度地发挥这种疗法对退伍军人的有益潜力。

DESCRIPTION (provided by applicant): PROJECT SUMMARY Atherosclerosis remains the leading cause of death and disability in the United States. Current therapeutic modalities for the treatment of severe atherosclerosis have high failure rates due to the development of restenosis secondary to neointimal hyperplasia. Nitric oxide (NO) is a small vasoprotective molecule that is known to inhibit the development of neointimal hyperplasia. As part of our prior VA Merit funding cycle, we developed several different NO-based therapies that successfully reduced neointimal hyperplasia in animal models. However, many veterans have diabetes mellitus (DM), a disease that alters the local arterial response to injury. In fact, patients with DM have been shown to have worse outcomes following vascular interventions due to aggressive neointimal hyperplasia. This led us to question whether NO-based therapies would be effective in this patient population. Preliminary data generated in our laboratory suggested that NO-based therapies have dramatically different efficacies in animal models of type I and type II diabetes. We found that NO was more efficacious at inhibiting neointimal hyperplasia in a rodent model of type II diabetes, yet completely ineffective in a rodent model of type I diabetes. These differences appear to be related to insulin levels. Thus, given that diabetes is common among veterans with severe atherosclerosis, and that these patients are most in need of a therapy to improve patency rates, it is critically important to further evaluate the efficacy of NO-based therapies in these diseases. Our hypothesis is that NO-mediated inhibition of neointimal hyperplasia is regulated by the insulin signaling pathway. Thus, the specific aims of this proposal are: Specific Aim 1: Characterize the effect of insulin and glucose on the ability of NO to regulate proliferation, migration, cell death, and reactive oxygen species in vascular smooth muscle cells (VSMC), endothelial cells, and adventitial fibroblasts in vitro. Specific Aim 2: Evaluate the efficacy of NO at inhibiting neointimal hyperplasia in vivo in animal models of type I and type II DM with and without insulin therapy. Specific Aim 3: Define the mechanism by which the insulin signaling pathway regulates the downstream beneficial effects of NO in the vasculature. Specifically, the mitogen activated protein kinase pathway will be manipulated using gain- and loss-of-function strategies. Preventing the development of neointimal hyperplasia in patients, especially those with diseases such as DM, will have a significant impact on patient care. Since patients with diabetes have an increased need for vascular interventions and have worse outcomes following interventions, this population would benefit greatly from a therapy that will improve outcomes. The studies in this proposal are novel, as no researcher has examined the role of NO in type I or type II DM. Thus, the data generated from this proposal will make a significant contribution to what is known about NO vascular biology and will lead to the development of innovative strategies to prevent neointimal hyperplasia in diabetic patient populations. Ultimately, by having a greater understanding of the pathways that regulate the downstream beneficial effects of NO in the vasculature, better NO-based therapies can be developed for our patients, thereby maximizing the beneficial potential this therapy will have for our veterans.