PFAS accelerate atherosclerosis through modulation of bile acid metabolism

项目总结 心血管疾病是美国和世界范围内的主要死亡原因，动脉粥样硬化 心脏病是一种特别沉重的负担。全氟和多氟烷基物质(PFAS)是一类普遍存在的 与心脏代谢性疾病风险因素增加相关的人造化学物质(即， 循环胆固醇增加)，或与动脉粥样硬化相关的主要结果，包括中风/心脏病发作 流行病学研究。目前还没有使用啮齿动物模型研究PFAS加速动脉粥样硬化的报道。 最近的啮齿动物研究表明，PFAS可以增加循环中的胆固醇，但这些研究依赖于 主要是在表现出脂蛋白胆固醇组分模式(极低密度脂蛋白，低密度脂蛋白，高密度脂蛋白)的野生型小鼠身上 与人类相反，而且不会在主动脉内形成损害。绕过这个问题，并拥有 一个实验模型，结果可以直接外推到人类身上，我们将使用低密度 脂蛋白受体缺陷小鼠(Ldlr-/-)，这些小鼠具有与人类一样的血脂特征，以确定PFAS- 介导性的胆固醇水平升高会导致病理性动脉粥样硬化。最近，我们发表了一篇 野生型小鼠喂食致动脉粥样硬化的食物，并暴露于5种与环境相关的PFA的简单混合物中 (全氟辛烷磺酸、全氟辛烷酸、全氟辛烷磺酸和全氟辛烷)12周后，循环胆固醇和胆汁增加。 酸。在初步研究中，我们遵循相同的暴露范例，观察到血液循环增加 Ldlr-/-小鼠体内的胆固醇。在这里，我们建议使用一个简单的PFAS混合物来扩展我们最初的观察结果 一个完整的因素设计，并检查动脉粥样硬化病变的形成。循环中的胆固醇水平可以 通过与饮食中胆固醇吸收、从头合成胆固醇有关的机制进行调节 排泄物。我们的初步研究表明，接触该混合物的ldlr-/-小鼠胆汁酸降低。 回肠重摄取转运体的排泄和诱导(尤其是顶端钠依赖胆汁酸 传送器；ASBT)。我们提议的研究将使用对ASBT有选择性的药物和大量标记的甾醇 要确认ASBT的诱导是关键。最后，为了在人类队列中验证其中一些观察结果，我们 最近从Anniston社区健康调查(ACHS)中测量了血清中的PFAS，我们报告说 居民高度暴露于全氟辛烷磺酸，我们现在建议测量储存样本中的胆汁酸。我们会 使用混合方法显示1)全氟辛烷磺酸混合物与增加的胆固醇在统计学上相关，以及2)这些 这种联系是通过增加循环中的胆汁酸来调节的。我们假设全氟辛烷磺酸加速 通过改变胆固醇排泄为胆汁酸而导致的动脉粥样硬化。我们的具体目标是：1)检验假设 环境相关的全氟辛烷磺酸混合物加速了LDLR-/-小鼠的动脉粥样硬化。2)测试 假设PFAS通过ASBT破坏胆汁酸的再摄取导致循环中胆固醇的增加- 相关机制。3)检查全氟辛烷磺酸混合物与循环胆汁酸之间的关系，并检测 如果是这样的话，全氟辛烷磺酸混合物和胆固醇之间的联系可以用这些物质的增加来解释。

PROJECT SUMMARY Cardiovascular diseases are the leading cause of death in the United States and worldwide, and atherosclerotic heart disease is particular burdensome. Per- and polyfluoroalkyl substances (PFAS) are a class of ubiquitous man-made chemicals that have been associated with increased risk factors for cardiometabolic disease (i.e., increased circulating cholesterol), or major outcomes related to atherosclerosis including stroke/heart attacks in epidemiological studies. No studies have reported on PFAS accelerated atherosclerosis using rodent models. Recent rodent studies have shown PFAS can increase circulating cholesterol, but these studies have relied primarily on wildtype mice which display lipoprotein cholesterol fraction patterns (VLDL, LDL, HDL) that are opposite of humans, and which do not develop lesions within the aorta. To circumvent this problem and to have an experimental model from which results can be directly extrapolated to humans, we will use Low Density Lipoprotein Receptor deficient mice (Ldlr -/-), which have lipid profiles like humans, to determine if PFAS- mediated increases in cholesterol levels lead to pathological atherosclerosis. Recently, we published that wildtype mice fed an atherogenic diet and exposed to a simple mixture of 5 environmentally relevant PFAS (PFOS, PFOA, PFNA, PFHxS, and GenX) for 12 weeks resulted in increased circulating cholesterol and bile acids. In preliminary studies, we followed the same exposure paradigm and observed increased circulating cholesterol in Ldlr -/- mice. Here, we propose to extend our initial observations using a simple PFAS mixture to a full factorial design and examine atherosclerotic lesion formation. Circulating cholesterol levels can be modulated through mechanisms related to dietary cholesterol absorption, de-novo cholesterol synthesis, and fecal excretion. Our preliminary studies show that Ldlr -/- mice exposed to the mixture show decreased bile acid excretion and induction of reuptake transporters in the ileum (especially apical sodium dependent bile acid transporter; ASBT). Our proposed studies will use pharmaceuticals selective for ASBT and mass labeled sterols to confirm ASBT induction is critical. Finally, to validate some of these observations in a human cohort, we recently measured PFAS in serum from the Anniston Community Health Surveys (ACHS) and we reported that residents were highly exposed to PFOS, and we now propose to measure bile acids in stored samples. We will use mixture methods to show 1) PFAS mixtures statistically correlate with increased cholesterol, and 2) these associations are mediated through increases in circulating bile acids. We hypothesize that PFAS accelerate atherosclerosis by altering cholesterol excretion as bile acids. Our specific aims are: 1) To test the hypothesis that mixtures of environmentally relevant PFAS accelerate atherosclerosis in Ldlr -/- mice. 2) To test the hypothesis that PFAS disrupts bile acid reuptake leading to increases in circulating cholesterol through ASBT- related mechanisms. 3) To examine the association between PFAS mixtures and circulating bile acids and test if that the association between PFAS mixtures and cholesterol can be explained by increases in these.