Metabonomic Stratification of Fatty Liver Disease

非酒精性脂肪性肝病(NAFLD)指的是一系列肝脏损害，分四个主要阶段逐步发展，特征是过量脂肪在肝脏中积聚。据认为，它影响了西方国家20%-30%的人口，并在全球范围内日益流行。NAFLD的确切发病机制尚不完全清楚。近年来，肠道微生物群对肝功能的影响已经被广泛研究，一些肠道代谢生物标志物已经被认为与非酒精性脂肪性肝炎(NASH)的发生有关，NASH是NAFLD的第二阶段。这些代谢特征包括芳香族氨基酸(AAA)、支链氨基酸(BAA)和苯乙酸(PAA)的失衡，已发现苯乙酸(PAA)可通过人-鼠粪便微生物区移植(FMT)促进肝脏脂肪变性的表型。了解肠道微生物群产生的代谢物对NASH的贡献有助于开发精确的微生物组靶向治疗方法。然而，肠道微生物组与NAFLD疾病进展和发病机制的确切分子机制联系仍然不清楚。一种治疗或预防NASH的新方法可能涉及对微生物组进行广泛的分子表型分析，以预测患者对NASH的易感性，然后操纵肠道微生物区系。越来越多的证据表明，与微生物组相关的干预措施，如FMT，在治疗NAFLD方面是有前景的，但缺乏精心设计和标准化的临床研究。然而，在确定肠道微生物群引发NASH的途径之前，微生物组靶向治疗的发展将受到限制。这些实验将通过非靶向代谢组学结合统计分析来展示NASH患者和健康对照组之间新的肠道微生物组代谢特征的差异，并将探讨FMT作为NASH患者肠道微生物组靶向治疗的有效性。这将通过识别健康个体的肠道微生物区系代谢生物标记物来实现，以确定FMT的理想捐赠者的代谢特征，并建立全面的对照。来自电波研究的健康个体的可靠代谢特征将与来自生物库和圣玛丽医院肝脏诊所的NASH患者的代谢特征进行比较。代谢表型用于检测与NASH相关的最相关的肠道微生物区系代谢生物标志物。这将通过核磁共振(核磁共振)光谱和质谱学(MS)的非定向代谢图谱来促进。非靶向代谢谱分析允许对肠道代谢组进行全面分析，并发现新的相关代谢生物标志物。此外，NASH患者FMT后的代谢生物标志物和肝脏表型将通过非靶向元基因组学共同分析并与FLORINASH数据集相关联，以确定微生物群激发NASH的临时途径。在本实验中，假设NASH患者的代谢型将被修复以模拟FMT后健康对照组的代谢表型，并通过深入的鸟枪元基因组分析进一步证实。

Non-alcoholic Fatty Liver Disease (NAFLD) refers to a spectrum of liver damage that progressively develops in four main stages and is characterized by the accumulation of excess fat in the liver. It is thought to affect 20 - 30% of western countries' population with an increasing worldwide prevalence. The exact pathogenesis of NAFLD remains incompletely understood. In recent years the effect of the gut microbiome on liver function has been extensively studied and several gut-metabolic biomarkers have been correlated to the development of Non-alcoholic Steatohepatitis (NASH), the second stage of NAFLD. These metabolic signatures include imbalances in aromatic amino acids (AAA), branch-chain amino acids (BAA) and phenylacetic acid (PAA), which has been found to prompt the hepatic steatosis phenotype by a human-to-mouse Faecal Microbiota Transplantation (FMT).Understanding the contribution of the metabolites produced by the gut microbiome to NASH could allow for the development of precision microbiome-targeted therapies. However, the exact molecular mechanistic links of the gut microbiome to disease progression and pathogenesis in NAFLD remain elusive. A novel approach to treat or prevent NASH may involve extensive molecular phenotyping of the microbiome for the prediction of susceptibility to NASH in patients followed by the manipulation of the gut microbiota. There is increasing evidence that microbiome-related interventions in NAFLD such as FMT are promising however there is a lack of well-designed and standardized clinical studies. Nevertheless, until the pathways by which the gut microbiome provokes NASH are identified, the development of microbiome-targeted therapies will be restricted.These experiments will demonstrate novel gut-microbiome metabolic signature differences between patients with NASH and healthy controls through untargeted metabolomics coupled with statistical analysis and will investigate the effectiveness of FMT as a method of gut-microbiome targeted therapy for NASH patients. This will be carried out by identifying gut-microbiota metabolic biomarkers in healthy individuals to determine the metabolic profile of the ideal donor for FMT and to establish a comprehensive control.Desirable metabolic signatures of healthy individuals from the AIRWAVE study will be compared with metabolic profiles of NASH patients from the Biobank and the Liver Clinic at St Marys Hospital. Metabolic phenotyping is used for the detection of the most relevant gut-microbiota metabolic biomarkers associated with NASH. This will be facilitated through untargeted metabolic profiling by Nuclear Magnetic Resonance (NMR) spectroscopy and Mass Spectrometry (MS). Untargeted Metabolic Profiling allows for comprehensive analysis of the gut metabolome and the discovery of new associated metabolic biomarkers. Furthermore, the metabolic biomarkers and liver phenotypes of NASH patients post-FMT will be co-analysed and correlated to the FLORINASH dataset through untargeted metagenomics to identify the casual pathways by which the microbiome incites NASH.In this experiment, it is hypothesised that the metabotype of patients with NASH will be reconditioned to mimic the metabolic phenotype of a healthy control post FMT and further confirmed by in-depth shotgun metagenomic analysis.