Atomic Force Microscopic Studies of Dissecting Aneurysm

描述（申请人提供）：工业化学品N-（2-氨基乙基）乙醇胺（AEEA）在世界范围内有着巨大的生产和使用。人类会在环境中接触到AEEA，而AEEA存在于各种常见产品中。血管是许多环境毒素的目标。此外，人们越来越认识到，血管疾病开始于儿童时期，并可能与产前暴露有关。这个实验室和其他实验室已经发现，在怀孕的大鼠（水坝）的第三个月给予AEEA，会导致新生幼鼠的血管病变，称为夹层主动脉瘤，或DAA。DAA是胸主动脉肌壁的突然撕裂或撕裂。在人类中，DAA影响青少年至成年早期，导致远端血管闭塞、主动脉破裂和猝死。DAA与几种描述良好的临床综合征相关，但绝大多数DAA是零星发生的，没有已知的遗传缺陷，高血压是唯一明确的危险因素。这项拟议研究的长期目标是更好地了解导致动脉夹层的主动脉壁物理弱化；通过在体内模型、血管细胞和自发性高血压大鼠中了解这些机制，可以设计出诊断和预防人类DAA的策略。待验证的假设是，AEEA的毒性损伤导致主动脉壁（或中膜）血管平滑肌细胞（VSMCs）损伤、功能失调的胎儿胶原纤维形成。生物物理性质紊乱，血管壁变弱。所提出的研究的基本原理是，通过了解导致解剖的物理和分子缺陷，可以设计预防或减轻DAA的策略。该假设将通过两个特定目的来解决：首先，在体内或体外AEE暴露后，将确定主动脉主要结构蛋白（胶原蛋白、弹性蛋白）的物理缺陷。这将通过原子力显微镜（AFM）测量主动脉基质和分离分子的物理特性来完成，原子力显微镜是一种测量皮牛顿分子力的技术。在Specific Aim #2中，血管夹层的潜在机制和高血压（人类的一个危险因素）的作用将通过以下方式揭示：a)通过生化和分子技术表征分离的VSMCs产生的基质缺陷，以及b)确定对照组和自发性高血压大鼠的产前AEEA效应。这些结合体内、体外、生物物理和分子方法将确定结构/分子毒性作用

DESCRIPTION (provided by applicant): The industrial chemical N-(2-aminoethyl) ethanolamine (AEEA) has enormous worldwide production and use. Human environmental exposures to AEEA occur, and AEEA is found in a variety of common products. Blood vessels are the target of many environmental toxins. Furthermore, it is becoming increasingly recognized that vascular disorders begin in childhood, and may be related to prenatal exposure. This and other laboratories have found that AEEA, given to pregnant rats (dams) during their third trimester, results in a vascular lesion in newborn pups known as dissecting aortic aneurysm, or DAA. DAA is the sudden tearing, or splitting of the layers of the muscular wall of the thoracic aorta. In humans, DAA affects those in the teen years to early adulthood, resulting in occlusion of distal vessels, aortic rupture, and sudden death. DAA is associated with several well-described clinical syndromes, but the vast majority of DAAs occur sporadically, without known genetic defects, and with hypertension as the only clear-cut risk factor. The long-term goal of this proposed research is to better understand the physical weakening of the aortic wall that underlies arterial dissection; by understanding these mechanisms in this in vivo model, in vascular cells, and in spontaneously hypertensive rats, strategies for diagnosis and prevention of human DAA can be devised. The hypothesis to be tested is that AEEA's toxic insult causes damaged, dysfunctional fetal collagen fibrillogenesis by vascular smooth muscle cells (VSMCs) of the aortic wall (or media). Deranged biophysical properties and weakening of the blood vessel wall result. The rationale for the proposed studies is that by understanding the physical and molecular defects that lead to dissection, strategies to prevent or attenuate DAA can be devised. The hypothesis will be addressed by two Specific Aims: First, physical defects in the aorta's major structural proteins (collagen; elastin) will be defined after in vivo or in vitro AEE exposure. This will be accomplished by measuring physical characteristics of aortic matrix and isolated molecules with atomic force microscopy (AFM), a technique that measures piconewton molecular forces. In Specific Aim #2, mechanisms underlying vascular dissection and the role of hypertension (a risk factor in humans) will be revealed by: a) characterizing defects from matrix produced by isolated VSMCs through biochemical and molecular techniques, and b) defining prenatal AEEA effects in control and spontaneously hypertensive rats. These combined in vivo, in vitro, biophysical and molecular approaches will identify the structural/molecular toxic effects of AEEA that weaken the aortic wall to result in DAA.