Metabonomic Stratification of Fatty Liver Disease

非酒精性脂肪性肝病（NAFLD）指的是一系列肝损伤，分四个主要阶段逐步发展，其特征是肝脏中过量脂肪的积累。据认为，它影响了西方国家20 - 30%的人口，并在世界范围内日益流行。NAFLD的确切发病机制尚不完全清楚。近年来，肠道微生物组对肝功能的影响得到了广泛的研究，一些肠道代谢生物标志物与非酒精性脂肪性肝炎（NASH）的发展有关，NASH是NAFLD的第二阶段。这些代谢特征包括芳香氨基酸（AAA）、支链氨基酸（BAA）和苯基乙酸（PAA）的失衡，通过人-小鼠粪便微生物群移植（FMT）发现，这些代谢特征促进了肝脏脂肪变性表型。了解肠道微生物组产生的代谢物对NASH的贡献可以促进精确微生物组靶向治疗的发展。然而，肠道微生物群与NAFLD疾病进展和发病机制的确切分子机制联系仍然难以捉摸。一种治疗或预防NASH的新方法可能涉及广泛的微生物组分子表型，以预测患者对NASH的易感性，然后对肠道微生物群进行操作。越来越多的证据表明，微生物组相关干预NAFLD如FMT是有希望的，但缺乏精心设计和标准化的临床研究。然而，在确定肠道微生物组引发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与统计分析相结合，证明NASH患者与健康对照组之间新的肠道微生物代谢特征差异，并将研究FMT作为NASH患者肠道微生物组靶向治疗方法的有效性。这将通过识别健康个体的肠道微生物群代谢生物标志物来确定FMT理想供体的代谢特征，并建立全面的控制。AIRWAVE研究中健康个体的理想代谢特征将与来自生物银行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群代谢生物标志物。这将通过核磁共振（NMR）光谱和质谱（MS）的非靶向代谢分析来促进。非靶向代谢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，将通过非靶向宏基因组学共同分析fmt后NASH患者的代谢生物标志物和肝脏表型，并将其与FLORINASH数据集相关联，以确定微生物组刺激NASH的偶然途径。在本实验中，假设NASH患者的代谢型将被修复以模仿健康对照者FMT后的代谢表型，并通过深入的散弹枪宏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.