Hepatic Encephalopathy in Alcoholic Cirrhosis: A Systems Biology Approach

描述(由申请人提供)：酒精性肝病和肝硬变(ALD)是与酒精相关的死亡和残疾的主要原因。肝性脑病(HE)是ALD的严重并发症，以一系列神经认知功能障碍为特征。HE的发病机制受肠道菌群衍生因子、宿主对这些因子的反应、这些因子对肝功能的影响、潜在肝病的严重程度和门体分流的影响。在ALD中，酒精对认知功能的直接影响以及它对驱动HE的其他因素的间接影响增加了另一层复杂性。因此，肠-肝-脑轴是一个复杂的系统，其在ALD中的扰动在ALD的HE发生中起着核心作用。不幸的是，在HE和ALD中，大多数文献都集中在末端器官上，而不是认为它们是一个复杂的生物系统。因此，肠道菌群、肠道、肝脏和脑之间的相互作用在ALD中HE的发生中的影响尚未得到充分的探讨。在HE的背景下，我们知识上的这种差距阻碍了对酒精诱导的肠道、肝脏和脑损伤机制的研究。在这项提案中，我们将通过检验以下中心假设来解决这一未得到满足的需求：与非酒精性肝硬化症患者相比，酒精性肝硬化症患者的肠道菌群和功能发生了特定的变化，与促炎环境和内毒素血症以及相关的脑功能受损和肝性脑病有关。我们将通过以下具体目标来检验这一假说：使用系统生物学方法，确定酒精性肝硬变和肝性脑病患者与非酒精性肝硬变患者相比，肠道菌群功能和种群的变化之间的联系及其对认知的相关影响。ALD和肝硬变(伴或不伴HE)的受试者将与因非酒精性脂肪性肝病(NAFLD)而导致的肝硬变(伴或不伴HE)的受试者进行比较。将在每个患者中研究表现组、微生物组、代谢组和转录组。症状包括饮酒、肝硬变严重程度、HE的存在、认知功能(心理测试、脑磁共振波谱(MRS)和扩散张量成像)和全身炎症状态(内毒素和内皮功能障碍)。肠道微生物组将使用长度异质性聚合酶链式反应和粪便和结肠粘膜的多标签焦磷酸测序(MTPS)进行分析。代谢组将使用尿液和血清MRS进行研究，肠道微生物区系的转录组或功能能力将使用深度MTPS进行分析。最终的系统生物学分析将展示HE和ALD之间的关键联系，这些联系将描述可能形成未来试验重点的特定靶点。它还将确定ALD和NAFLD在HE发病机制上的区别，从而揭示这些不同疾病中HE发生的机制差异。研究人员非常适合进行这些研究，因为他们的专业知识、可获得的对象和环境。 与公共健康相关：饮酒的患者会损害他们的肝脏、大脑以及肠道细菌，所有这些都会影响他们戒酒后很长一段时间的生活质量和生存。这项提议将通过比较过去喝酒和不喝酒的患者来研究肠道细菌的变化是否可以解释酒精对大脑和整个身体的这些影响。这一结果将帮助我们找到新的治疗靶点，以防止酒精对肠道、肝脏和大脑的这些有害影响

DESCRIPTION (provided by applicant): Alcoholic liver disease and cirrhosis (ALD) is a leading cause of alcohol-related death and disability. Hepatic encephalopathy (HE) is a serious complication of ALD and is characterized by a spectrum of neuro-cognitive dysfunction. The pathogenesis of HE is driven by intestinal microflora-derived factors, the host response to these factors, the impact of these factors on hepatic function, the severity of the underlying liver disease and portasystemic shunting. In ALD, another layer of complexity is added by the direct effects of alcohol on cognitive function and its indirect effects on the other factors that drive HE. Thus, the gut-liver-brain axis represents a complex system and its perturbation in ALD plays a central role in the genesis of HE in ALD. Unfortunately, in both HE and ALD, most of the literature has focused on end-organs rather than consider them a complex biologic system. The impact of the interactions between the intestinal microflora, intestine, liver and the brain in the genesis of HE in ALD has therefore not been fully explored. This gap in our knowledge has hindered the investigation of the mechanisms of alcohol-induced gut, liver and brain injury in the context of HE. In this proposal, we will address this unmet need by testing the central hypothesis that: patients with alcoholic cirrhosis have a specific alteration in their gut flora population and function that is linked with a pro- inflammatory milieu and endotoxemia and associated impaired brain function and hepatic encephalopathy, compared to those who do not have alcoholic cirrhosis.. We will test this hypothesis by the following specific aim: To determine the association between changes in gut microflora function and population and their associated effects on cognition in patients with alcoholic cirrhosis and hepatic encephalopathy compared to those with non-alcoholic cirrhosis using a systems biology approach. Subjects with ALD and cirrhosis (with or without HE) will be compared to those with cirrhosis (with or without HE) due to non- alcoholic fatty liver disease (NAFLD). The phenome, the microbiome, the metabolome and the meta- transcriptome will be studied in each patient. The phenome will be characterized by alcohol use, cirrhosis severity, presence of HE, cognitive function (psychometric tests, brain MR spectroscopy (MRS) and diffusion tensor imaging) and systemic inflammatory state (endotoxin and endothelial dysfunction). The gut microbiome will be analyzed using Length-heterogeneity PCR and Multi-tagged pyrosequencing (MTPS) of stool and colonic mucosa. The metabolome will be studied using urine and serum MRS, and the meta-transcriptome or functional capacity of the gut microflora will be assayed using deep MTPS. The final Systems Biology analysis will demonstrate key linkages between HE and ALD that will delineate specific targets that could form the focus of future trials. It will also define distinctions in the HE pathogenesis in ALD compared to NAFLD that would shed light into the mechanistic differences of HE development in these divergent diseases. The investigators are well suited to perform these studies because of their expertise, availability of subjects and the environment. PUBLIC HEALTH RELEVANCE: Patients who drink alcohol can hurt their liver, brain as well as change the bacteria in their bowels, all of which can affect their quality of life and survival long after they quit drinking. This proposal will study whether change in the bowel bacteria can explain these effects of alcohol on the brain as well as the entire body by comparing patients who used to drink to those who do not drink. The results will help us find newer targets for treatments to prevent these injurious effects of alcohol on the bowels, liver and brain