Sanal Madhusudana Girija
Special Center for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India.
World J Gastroenterol. 2008 Feb 14;14(6):831-44. doi: 10.3748/wjg.14.831.
Nonalcoholic fatty liver disease (NAFLD) is a group of diseases with excess fat in liver in the absence of a poorly defined limit of alcohol consumption. Most common variety, a universal public health problem, is associated with insulin resistance caused by a host of genetic and epigenetic defects modulated by life style and environmental factors. In fact the term NAFLD is loose to incorporate so many etiologies except alcoholism and few other etiologies, presenting as fat in liver. However as a sign fatty liver is very important in predicting the risk of diabetes, cardiovascular disease, stroke, cirrhosis and cancer. Abnormal fat accumulation can result from several defects in nuclear receptors associated with lipid sensing, synthesis and oxidation like LXR, FXR, SREBP, ChREBP and PPAR; defects in the lipid influx-efflux channels, insulin signaling, proteins involved in fatty acid catabolism, defects in adipose tissue development and function, inappropriate nutrition and finally defects in neural regulatory mechanisms. The progress of the disease is determined by the basic defects which results in fat accumulation, an individual's immunological response to the accumulated fat and its derivatives and the oxidant stress response. Congregation of unrelated genetic defects under same diagnosis 'NAFLD' can result in inefficient patient management. Further studies are required to understand the molecular basis of fatty liver to enable a personalized management of diseases presenting as fatty liver in the absence of alcohol abuse.
非酒精性脂肪性肝病(NAFLD)是一组在酒精摄入量未明确界定的情况下肝脏脂肪过多的疾病。最常见的类型是一个普遍的公共卫生问题,与由多种遗传和表观遗传缺陷引起的胰岛素抵抗有关,这些缺陷受生活方式和环境因素调节。事实上,NAFLD这个术语很宽泛,涵盖了除酗酒和其他少数病因之外的众多病因,表现为肝脏脂肪堆积。然而,作为一种体征,脂肪肝在预测糖尿病、心血管疾病、中风、肝硬化和癌症风险方面非常重要。异常脂肪堆积可能源于与脂质感知、合成和氧化相关的核受体的多种缺陷,如肝X受体(LXR)、法尼酯X受体(FXR)、固醇调节元件结合蛋白(SREBP)、碳水化合物反应元件结合蛋白(ChREBP)和过氧化物酶体增殖物激活受体(PPAR);脂质流入-流出通道缺陷、胰岛素信号传导、参与脂肪酸分解代谢的蛋白质、脂肪组织发育和功能缺陷、营养不当,以及最终的神经调节机制缺陷。疾病的进展取决于导致脂肪堆积的基本缺陷、个体对堆积脂肪及其衍生物的免疫反应以及氧化应激反应。在同一诊断“NAFLD”下聚集不相关的遗传缺陷可能导致患者管理效率低下。需要进一步研究以了解脂肪肝的分子基础,从而能够在无酒精滥用的情况下对表现为脂肪肝的疾病进行个性化管理。