2010-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/710880摘要：非酒精性脂肪肝疾病是全世界造成慢性肝病最常見的原因。肥胖是非酒精性脂肪肝疾病發生的重要危險因子。由於過去缺乏前瞻性追蹤的研究，我們並不知道肝臟如何病變為脂肪肝，以及如何從單純脂肪肝惡化為脂肪性肝炎，這其中牽涉的因素尚未完全了解。氧化壓力(oxidative stress)是造成非酒精性脂肪性肝疾病的一項重要因素。過去研究報告發現膽色素(bilirubin)有抗氧化的功能，而UGT1A1 基因的變異是影響膽色素濃度的重要因素。我們預期UGT1A1 基因的變異(polymorphism)會影響非酒精性脂肪性肝疾病的發生，將研究肥胖兒童之UGT1A1 基因的變異。此外，有許多證據顯示內毒素(endotoxin)會經由甲型腫瘤壞死因子(TNF-α)而引起脂肪性肝炎。在人類的研究中發現，非酒精性脂肪性肝炎患者的腸內細菌較正常控制組有明顯增加的情形。這些研究證實腸內細菌群落對於非酒精性脂肪肝炎有致病性的影響。所以本研究的目的是要建立前瞻性追蹤研究，以瞭解兒童非酒精性脂肪性肝疾病的盛行率與自然病史，並分析影響病程的危險因子。並且探討腸道內的細菌群落對於兒童非酒精性脂肪性肝炎的影響與角色。本研究期望能對於此一逐漸重要的兒童肝臟疾病能有更深入的了解。在本三年計畫中，我們將連續性每年追蹤五百名肥胖的兒童青少年(包含9 到10 歲250 名與13 歲250 名)。我們將測量體位指標、空腹血糖、胰島素、三酸甘油脂、膽固醇、高密度脂蛋白、與肝功能。對於持續ALT 異常超過3 個月以上者，我們將建議他們接受肝臟穿刺與肝臟核磁共振檢查來進一步評估他們脂肪肝病變的程度。我們將偵測受試者UGT1A1 基因的變異(UGT1A1*6 與UGT1A1*28) 。我們將分析該基因變異對於非酒精性脂肪性肝疾病的關聯性。另外，我們將收集新鮮糞便以研究肥胖兒童腸道微生物群落變化。利用聚合酶連鎖反應放大糞便中細菌16S核醣體RNA 的基因後，進行變性梯度膠電泳分析(DGGE)，來找出非酒精性脂肪性肝疾病病患與單純肥胖控制組之間糞便細菌群落的差異。對於一些有興趣的腸內細菌種類，進行即時聚合酶連鎖反應來定量分析。這部分的研究結果將會使我們進一步了解腸內細菌群落與人類寄主的交互作用如何來影響非酒精性脂肪性肝炎的致病機轉。總之，本研究將針對兒童非酒精性脂肪肝疾病的相關危險因子與自然史提供重要的資料。此外，我們將研究UGT1A1 基因變異與腸內細菌群落差異在非酒精性脂肪肝疾病的致病角色，這部分是一項在非酒精性脂肪肝疾病的重要先驅性研究。<br> Abstract: Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes ofchronic liver disease worldwide. Obesity is associated with the development of NAFLD,and insulin resistance is the key mechanism. Little is known about nature history ofNAFLD in children.Oxidative stress is increased in nonalcoholic fatty liver disease. Variants in theUGT1A1 gene contribute to increased bilirubin levels and bilirubin can act as anantioxidant. We hypothesize that variant UGT1A1 genotypes modify the risk forNAFLD development.We will compare bilirubin levels and UGT1A1 polymorphism inobese children and their normal control. In human study, intestinal bacterial overgrowthis more frequent in NASH patients than in controls. These findings suggest theunderlying mechanisms of intestinal bacteria in NASH.The aims of this study are: (1) to establish a cohort to prospectively analyze thenatural history of NAFLD in obese children; (2) to identify risk factor(s) that may affectthe expression and progression of NAFLD in obese children; (3) to investigate thepotential roles of intestinal bacteria in the pathogenesis of pediatric NAFLD.We expect to recruit 500 obese children (250 subjects for age group 9 and 10 years,250 subjects for age 13) and will be followed up once per year for 3 years. At each visit,anthropometric measurements, fasting blood sugar and insulin, lipid profiles, and liverfunction profiles. For subjects with abnormal ALT persisting for more than 3 months, wewill suggest liver biopsy and hepatic magnetic resonance imaging to investigate theseverity of hepatic steatosis, necroinflammation and fibrosis in their liver.The UGT1A1 genotypes (UGT1A1*6 and UGT1A1*28) will be detected. We willassess the effects of UGT1A1 genotypes on NAFLD, also we will use bilirubin level as asurrogate for oxidative stress.We will collect the stool samples from all subjects every year and analyze the fecalmicroflora.We will investigate population fingerprinting using denaturing gradient gelelectrophoresis (DGGE) analysis of 16S rRNA gene amplicons. In addition, we willenumerate several bacterial species by quantitative real-time polymerase chain reaction(real-time PCR). The microbial diversity of the intestinal bacterial ecosystem in patientswith NAFLD and patients with simple steatosis will be compared. This result willimprove understanding of host-microbe interaction in NASH.This study will offer the important information for the natural history of pediatricNAFLD. It is the first study in the world to incorporate UGT1A1 genotypes and theintestinal bacteria profile into the pathogenesis of NAFLD.