PFAS accelerate atherosclerosis through modulation of bile acid metabolism

项目摘要 心血管疾病是美国和世界范围内死亡的主要原因，动脉粥样硬化是导致死亡的主要原因。 心脏病是特别沉重负担。全氟烷基和多氟烷基物质（PFAS）是一类普遍存在的 与心脏代谢疾病的风险因素增加有关的人造化学物质（即， 循环胆固醇增加），或与动脉粥样硬化相关的主要结局，包括中风/心脏病发作， 流行病学研究。没有研究报告PFAS加速动脉粥样硬化使用啮齿动物模型。 最近的啮齿动物研究表明，PFAS可以增加循环胆固醇，但这些研究依赖于 主要是野生型小鼠，其显示脂蛋白胆固醇分数模式（VLDL、LDL、HDL）， 与人类相反，并且在主动脉内不发生病变。为了解决这个问题， 一个实验模型，其结果可以直接外推到人类，我们将使用低密度 脂蛋白受体缺陷小鼠（Ldlr -/-），其具有与人类相似的脂质谱，以确定PFAS- 介导的胆固醇水平增加导致病理性动脉粥样硬化。最近，我们发表了 喂食致动脉粥样硬化饮食并暴露于5种环境相关PFAS的简单混合物的野生型小鼠 (PFOS PFOA、PFNA、PFHxS和GenX）治疗12周，导致循环胆固醇和胆汁 acids.在初步研究中，我们遵循相同的暴露模式，观察到循环增加， Ldlr -/-小鼠中的胆固醇。在这里，我们建议使用简单的PFAS混合物来扩展我们的初步观察， 一个完整的析因设计和检查动脉粥样硬化病变的形成。循环胆固醇水平可以 通过与膳食胆固醇吸收、胆固醇从头合成和 粪便排泄我们的初步研究表明，Ldlr -/-小鼠暴露于混合物显示胆汁酸减少， 回肠中再摄取转运蛋白的排泄和诱导（尤其是顶端钠依赖性胆汁酸 转运蛋白; ASBT）。我们提出的研究将使用药物选择性ASBT和质量标记的甾醇 确认ASBT诱导是至关重要的最后，为了在人类队列中验证这些观察结果，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。我们将 使用混合物方法显示1）PFAS混合物与胆固醇升高具有统计学相关性，2）这些 通过循环胆汁酸的增加来介导相关性。我们假设PFAS加速了 动脉粥样硬化通过改变胆固醇作为胆汁酸的排泄。我们的具体目标是：1）检验假设 环境相关PFAS的混合物加速Ldlr -/-小鼠的动脉粥样硬化。2)测试 假设PFAS破坏胆汁酸再摄取，导致通过ASBT增加循环胆固醇- 相关机制。3)检查PFAS混合物与循环胆汁酸之间的相关性， 如果PFAS混合物与胆固醇之间的联系可以通过这些物质的增加来解释的话。

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.