Roles of oxidation and inflammation in aortic stiffening

描述（由申请人提供）：越来越明显的是，大血管的电容功能，特别是主动脉，通过调节收缩期部分卒中容量，降低收缩压和维持舒张期全身灌注来调节血流动力学。常见的临床情况，包括衰老、胰岛素抵抗、糖尿病和高血压本身都与这种弹性功能的丧失有关，容易发生收缩期高血压。这些变化背后的机制尚不清楚；然而，临床研究表明，炎症和氧化损伤与动脉硬化参数有关。生化和实验研究也表明活性氧在弹性蛋白和胶原蛋白的修饰中会促进动脉硬化。我们实验室和其他人先前的工作表明，活性氧在高血压中起着关键作用。最近，我们发现适应性免疫系统和细胞因子IL-17在高血压的发生中起重要作用。在拟议的研究中，我们将采用独特的转基因小鼠，使我们能够增加或减少血管平滑肌中活性氧的水平，以研究这些物质如何促进动脉硬化、血管胶原蛋白和弹性蛋白含量以及这些物质的生化修饰。我们将通过使用我们制造的小鼠来实现这一目标，这些小鼠允许我们删除细胞外超氧化物歧化酶（SOD3）或NADPH氧化酶亚基p22phox。我们假设通过删除SOD3来增加血管氧化损伤会增强，而通过删除p22phox来抑制氧化应激会防止动脉硬化。在其他研究中，我们将验证适应性免疫，特别是T细胞和细胞因子IL-17有助于动脉硬化的假设。我们认为RAG-1-/-和IL-17-/-小鼠在血管紧张素II输注期间不会发生动脉硬化，但T细胞的过继性转移会促进这些动物的动脉硬化。最后，我们假设动脉硬化，通过向目标组织（如远端血管和肾脏）传递增加的压力；会促进炎症反应和T细胞活化，从而进一步升高血压。为了验证这一假设，我们将弹性蛋白缺乏症小鼠（Eln小鼠）与rag1 -/-小鼠杂交。我们假设，与Eln小鼠相比，这些动物的血压会降低，T细胞的过继性转移将恢复这些动物的血压。这些研究将为动脉硬化的病因提供新的信息。我们在高血压生理学、结缔组织生物化学和心血管组织形态学方面的综合专业知识使我们在这些研究方向上处于独特的地位。

DESCRIPTION (provided by applicant): It has become increasingly apparent that the capacitance function of larger vessels, and in particular the aorta, modulates hemodynamics by accommodating a portion of stroke volume during systole, reducing systolic pressure and maintaining systemic perfusion during diastole. Common clinical conditions, including aging, insulin resistance, diabetes and hypertension per se are associated with loss of this elastance function, predisposing to systolic hypertension. The mechanisms underlying these changes remain unknown; however clinical studies have suggested that inflammation and oxidative injury are associated with parameters of arterial stiffening. Biochemical and experimental studies have also implicated reactive oxygen species in modifications of elastin and collagen that would promote arterial stiffening. Prior work from our laboratory and others demonstrated that reactive oxygen species play a critical role in hypertension. More recently, we have shown that the adaptive immune system and the cytokine IL-17 are important in the genesis of hypertension. In the proposed studies, we will employ unique, genetically modified mice that permit us to increase or decrease vascular smooth muscle levels of reactive oxygen species to study how these contribute to arterial stiffening, vascular collagen and elastin content and biochemical modifications of these. We will accomplish this by using mice we have made that allow us to delete either the extracellular superoxide dismutase (SOD3) or the NADPH oxidase subunit p22phox. We hypothesize that increasing vascular oxidant injury by deleting SOD3 will enhance, while inhibiting oxidant stress by deleting p22phox will prevent arterial stiffening. In other studies, we will test the hypothesis that adaptive immunity and in particular T cells and the cytokine IL-17 contribute to arterial stiffening. We propose that RAG-1-/- and IL-17-/- mice will not develop arterial stiffening during angiotensin II infusion, but that adoptive transfer of T cells will promote arterial stiffening in these animals. Finally, we hypothesize that arterial stiffening, by transmitting increased pressure to target tissues, such as distal vessels and the kidney; will promote an inflammatory response and T cell activation, which further increases blood pressure. To test this hypothesis, we will cross mice heterozygotic for elastin deficiency (Eln mice) with RAG-1-/- mice. We postulate that these animals will have reduced blood pressure compared to Eln mice, and that adoptive transfer of T cells will restore blood pressure in these animals. These studies will provide new information regarding the etiology of arterial stiffening. Our combined expertise in the physiology of hypertension, connective tissue biochemistry and cardiovascular histomorphology place us in a unique position to pursue these directions of research. PUBLIC HEALTH RELEVANCE: Project Narrative: Arterial stiffening is an important mediator of systolic hypertension; however the mechanisms responsible for changes in large vessel compliance remain undefined. This project will test the hypothesis that oxidative injury and the adaptive immune system interact to increase arterial stiffness. These studies promise to provide new information regarding hypertension, vascular disease and how alterations in arterial compliance predispose to inflammation.