Pathophysiology and Characterisation of NAFLD

描述（由申请人提供）：非酒精性脂肪性肝病（NAFLD）是美国最常见的肝脏疾病。NAFLD的高患病率很大程度上是基于肥胖和胰岛素抵抗患病率的持续增加。部分NAFLD患者进行性组织学损伤的基础尚不清楚。该项目的总体目标是：1)建立一个模型来识别组织学上更严重的NAFLD患者；2)更好地定义NAFLD组织学进展的病理生理基础。为了实现这些目标，提出了两个假设和具体目标。我们的第一个假设是，胰岛素敏感性、高胰岛素血症和/或亚临床炎症指数可以用来建立一个模型，能够识别组织学上更严重的NAFLD级别风险增加的患者。第一个具体目标是前瞻性筛选一组生物学参数，以确定具有组织学严重NAFLD风险的患者的能力，通过NAFLD分级来衡量。在一项针对不同严重程度NAFLD患者的初步研究中，我们发现组织学上更严重的NAFLD与更高的体脂百分比、更高的c反应蛋白和空腹胰岛素水平独立相关。与NAFLD严重程度密切相关的趋势还表现为IGFBP-1水平、体脂百分比、HGH水平和连续血糖监测。我们现在建议对这些和其他亚临床炎症、胰岛素敏感性、胰岛素样生长因子轴的标志物进行详细评估，并对1-3级NAFLD患者和对照组进行人体测量评估。我们的第二个假设是NAFLD中可能发生的炎症和进行性纤维化主要是由于氧化应激增加。第二个具体目标是确定NAFLD中氧化应激增加的机制和影响。氧化应激被认为是NAFLD肝细胞损伤的核心。我们的初步数据表明，在组织学进展性NASH患者中，氧化应激增加可能存在转录前基础。在这些实验的逻辑延伸中，我们现在建议使用高通量质谱分析，使用ICAT标记技术，测量1-3级NAFLD患者和对照组中肝脏蛋白质丰度的差异，包括过氧化物酶体蛋白。我们相信，这些实验将对组织学进展性NAFLD患者氧化应激增加的原因和影响产生机制上的见解。

DESCRIPTION (provided by applicant): Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease in the United States. The high prevalence of NAFLD is largely on the basis of relentless increases in the prevalences of obesity and insulin resistance. The basis of progressive histological injury in a proportion of patients with NAFLD is poorly understood. The overall goals of this project are to 1) develop a model to identify patients with more histologically severe grades of NAFLD and 2) better define the pathophysiological basis of histological progression of NAFLD. Two hypotheses and specific aims have been developed to achieve these goals. Our first hypothesis is that indices of insulin sensitivity, hyperinsulinemia and/or subclinical inflammation can be used to generate a model capable of identifying patients at increased risk for more histologically severe grades of NAFLD. The first specific aim is to prospectively screen a panel of biological parameters for their ability to identify patients at risk for histologically severe NAFLD, as measured by NAFLD grade. In a pilot study of patients with varying degrees of severity of NAFLD, we found that more histologically severe NAFLD is independently associated with greater percent body fat, higher C-reactive protein and fasting insulin levels. Strong trends for an association with severity of NAFLD grade were also seen for higher IGFBP-1 levels, % truncal fat, HGH levels, and continuous glucose monitoring profiles. We now propose to carry out detailed assessments of these and other markers of subclinical inflammation, insulin sensitivity, insulin-like growth factor axis and assessments of anthropometry in patients with grades 1-3 of NAFLD and in controls. Our second hypothesis is that the inflammation and progressive fibrosis that can occur in NAFLD are substantially due to increased oxidative stress. The second specific aim is to determine the mechanism and effects of increased oxidative stress in NAFLD. Oxidative stress is thought to be central to hepatocellular injury in NAFLD. Our preliminary data demonstrate a possible pre-transcriptional basis of increased oxidative stress in patients with more histologically progressive NASH. In a logical extension of these experiments, we now propose to use high-throughput mass spectrometry analysis, using an ICAT tagging technique, to measure differential hepatic protein abundance, including of peroxisomal proteins, in patients with NAFLD grades 1-3, and also in controls. We believe that these experiments will generate mechanistic insight into the cause and effects of increased oxidative stress in patients with histologically progressive NAFLD.