Fetal Determinants of Atherosclerosis

描述(由申请人提供)：我们之前的研究表明，动脉粥样硬化在胎儿发育期间就已经开始形成，孕妇在怀孕期间的高胆固醇血症与胎儿脂肪条纹的形成增加以及正常胆固醇血症儿童动脉粥样硬化的进展速度更快相关，这不能用传统的危险因素来解释。虽然在人类中，遗传差异可能起到一定作用，但我们假设，母体高胆固醇血症本身会导致胎儿动脉发生致病事件，从而决定他们日后对动脉粥样硬化的易感性。我们还假设，母体高胆固醇血症引起的氧化应激导致调节动脉粥样硬化形成的基因表达的持续变化。一个重要的推论是，母亲在怀孕期间降低胆固醇和抗氧化剂干预可能会为她们的后代提供长期的好处。利用遗传同质的动物模型，我们最近提供了直接证据，证明母体高胆固醇血症和氧化应激在促进胎儿病变形成和加速出生后动脉粥样硬化形成中的因果作用。我们还为动脉壁基因表达的持续调控提供了原则上的证据。我们现在建议更好地定义与母亲高胆固醇血症相关的宫内编程，确定影响出生后动脉粥样硬化易感性的基因，并调查怀孕期间的干预是否也降低了“正常胆固醇”母亲的后代的易感性。通过将低密度脂蛋白受体缺陷(LDLR-/-)小鼠的胚胎移植到治疗或未治疗的C57BL/6、LDLR-/-或apoE-/-小鼠中，可以实现不同水平的母体高胆固醇血症和抗氧化保护。随着时间的推移，后代将受到出生后动脉粥样硬化条件和病变形成的影响。激光捕获显微切割、基因芯片和聚合酶链式反应技术将被用来确定基因调控的持久性及其与动脉粥样硬化、基因产物的免疫细胞化学存在和氧化应激测量的相关性。这些研究将从根本上对子宫内编程和动脉粥样硬化形成机制产生新的见解，并可能建立一种新的预防方法。

DESCRIPTION (provided by applicant): We previously showed that atherogenesis already begins during fetal development and that maternal hypercholesterolemia during pregnancy is associated with enhanced fatty streak formation in fetuses and a much faster progression of atherosclerosis in normocholesterolemic children that could not be explained by conventional risk factors. Although in humans inherited genetic differences are likely to contribute, we hypothesize that maternal hypercholesterolemia per se induces pathogenic events in fetal arteries that determine their later susceptibility to atherosclerosis. We also hypothesize that oxidative stress caused by maternal hypercholesterolemia leads to persistent changes in the expression of genes modulating atherogenesis. An important corollary is that cholesterol lowering and antioxidant interventions in mothers during pregnancy may provide long-lasting benefits to their offspring. Using genetically homogeneous animal models, we recently provided direct evidence for the causal role of maternal hypercholesterolemia and oxidative stress in both enhanced fetal lesion formation and accelerated post-natal atherogenesis. We also provided proof in principle for persistent regulation of gene expression in the arterial wall. We now propose to better define the in utero programming associated with maternal hypercholesterolemia, to identify genes influencing post-natal susceptibility to atherosclerosis, and to investigate whether interventions during pregnancy also decrease the susceptibility in offspring of "normocholesterolemic" mothers. Different levels of maternal hypercholesterolemia and antioxidant protection will be achieved by transferring embryos of LDL receptor deficient (LDLR-/-) mice into treated or untreated C57BL/6, LDLR -/- or apoE -/- mice. Offspring will be subjected to post-natal atherogenic conditions and lesion formation followed over time. Laser-capture microdissection, gene microarray and PCR techniques will be used to determine persistence of gene regulation and its correlation with atherosclerosis, immunocytochemical presence of gene products and measurements of oxidative stress. These studies should yield fundamentally new insights into in utero programming and atherogenic mechanisms, and may establish a novel preventive approach.