Non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFL) includes a spectrum of clinicopathological conditions with increasing prevalence in the developed world. Although steatosis alone seems to have a benign course, those patients with the diagnosis of non-alcoholic steatohepatitis (NASH) can have a progressive course. Additionally, there is now evolving, indirect evidence that some of the patients with cryptogenic cirrhosis may be the result of 'burned-out' NASH. Although NAFL and NASH are associated with insulin-resistance syndrome, some patients with NAFL may have no obvious risk factors. Despite preliminary data from a number of pilot studies, no established therapies can be offered to patients with NASH. Over the next few years, a number of exciting research projects dealing with the epidemiology as well as the pathogenesis of NAFL are expected to be completed. It is anticipated that, through a better understanding of NAFL, more effective treatment protocols can be developed targeting only those patients with NASH that are at the highest risk for progression to cirrhosis and liver failure.     

Predictors of fibrosis in Asian patients with non-alcoholic steatohepatitis

Background and Aim: Non‐alcoholic steatohepatitis (NASH) is increasingly recognized as an important cause of chronic liver disease. However, data on Asians with NASH is lacking in the literature. The aim of the present study was to describe the clinical, biochemical and histological characteristics of NASH in Asians and to determine the predictors for septal fibrosis. Method: Sixty consecutive patients aged over 18 years with elevated serum alanine transferase, sonographic evidence of steatosis, and consent for liver biopsy were included. Patients with chronic hepatitis B or C, alcoholic, autoimmune, genetic, or drug‐induced liver disease were excluded. Clinical, biochemical and histological variables were tested for association with septal liver fibrosis (F2/3). Results: Median age of the cohort was 45.5 years (range 21–75 years) and 63% were male. Ninety percent of patients were obese (body mass index [BMI]≥ 25), 70% had hypertriglyceridemia, 68% had hypercholesterolemia, 58% had metabolic syndrome, 53% had hypertension, 47% had diabetes mellitus (DM), and 18% had obstructive sleep apnea. Sixty‐eight percent had gamma‐glutamyl transferase (GGT) ≥ 2 × upper limit of normal (ULN), 55% had alanine aminotransferase (ALT) ≥ 2 × ULN, and 23% had aspartate aminotransferase (AST) ≥ 2 × ULN. Of the 40 non‐diabetic patients undergoing oral glucose tolerance testing, 45% had normal tests, 30% had impaired glucose tolerance, 23% DM, and 2% impaired fasting glucose. Eighteen patients (30%) had septal fibrosis (F2/3), but none had cirrhosis. Necroinflammatory grade ≥ 2 (odds ratio [OR] 13), AST ≥ 2 × ULN (OR 5.3) and DM (OR 5) were significantly and independently correlated with septal fibrosis. Conclusion: Septal fibrosis is common in Asians with NASH. Necroinflammatory grade ≥ 2, AST ≥ 2 × ULN and DM are independent predictors for septal fibrosis.     

How common is non‐alcoholic fatty liver disease in the Asia–Pacific region and are there local differences?

Risk factors for development of non-alcoholic steatohepatitis include obesity, especially central adiposity, glucose intolerance or type 2 diabetes mellitus (T2DM), and dyslipidemia. Non-alcoholic fatty liver disease (NAFLD) is now considered a manifestation of metabolic syndrome. During the last two decades, NAFLD has become the most common chronic liver disease in North America and Europe, but until recently was thought to be uncommon (perhaps due to the lack of study) in Asia. Fatty liver can be identified on imaging modalities (ultrasonography, computed tomography scans, and magnetic resonance imaging) with high sensitivity, but steatohepatitis and fibrosis cannot be distinguished. Thus, an inherent drawback in studying the epidemiology of NAFLD is the lack of definitive laboratory tests, no uniform definition-with different studies using cut-off values of alcohol consumption from <20 g/week to 210 g/week, and case selections where biopsy was used for definition. In studies outside the region, the prevalence of NAFLD varies from 16% to 42% by imaging, and 15-39% of liver biopsies. The major risk factors for NAFLD, central obesity, T2DM, dyslipidemia, and metabolic syndrome, are now widely prevalent and are increasing geometrically in the Asia-Pacific region. It is therefore not surprising that NAFLD is common in this region. Estimates of current prevalence range from 5% to 30%, depending on the population studied. Central obesity, diabetes, and metabolic syndrome are the major risk factors. To date, however, data on the natural history and impact of NAFLD causing serious significant chronic liver disease are lacking and there is a need for prospective, cooperative studies.     

Impact of Pemafibrate in Patients with Hypertriglyceridemia and Metabolic Dysfunction-associated Fatty Liver Disease Pathologically Diagnosed with Non-alcoholic Steatohepatitis: A Retrospective,Single-arm Study

Objective The therapeutic effect of pemafibrate on metabolic dysfunction-associated fatty liver disease (MAFLD) remains unknown. This retrospective, single-arm study investigated the efficacy and safety of pemafibrate in MAFLD patients with hypertriglyceridemia. Methods A total of 10 patients who received pemafibrate (oral, 0.1 mg, twice a day) at Gunma Saiseikai Maebashi Hospital between September 2018 and September 2019 were included. All patients underwent a liver biopsy, and the disease grade and stage were pathologically assessed based on the FLIP algorithm. Results The median age was 66.0 (53.8-74.8) years old, and 5 patients (50.0%) were men. All patients were diagnosed with non-alcoholic steatohepatitis (NASH). The fasting and non-fasting triglyceride (TG) levels were 175 (149-247) mg/dL and 228 (169-335) mg/dL, respectively. The AST and ALT values at 6 months were significantly lower than at baseline [AST: 28.0 (22.0-33.8) U/L vs. 43.5 (24.0-55.0) U/L, p=0.008, ALT: 23.0 (14.8-26.5) U/L vs. 51.5 (23.0-65.3) U/L, p=0.005, respectively], especially in NASH patients with significant activity and advanced fibrosis (p=0.040 and 0.014, respectively). Fasting TG levels were significantly lower and HDL-C levels significantly higher at 6 months than at baseline (p=0.005 and 0.032, respectively). At six months, FIB-4, the aspartate aminotransferase-to-platelet ratio index, and the macrophage galactose-specific lectin-2 binding protein glycosylation isomer level were significantly improved compared with baseline (p=0.041, 0.005 and 0.005, respectively). Treatment-related adverse events were not observed. Conclusion Pemafibrate treatment may be safe and effective for MAFLD patients with hypertriglyceridemia.     

脂肪细胞脂肪酸结合蛋白在非酒精性脂肪性肝病患者肝脏中的表达及意义

[目的]研究脂肪细胞特异性蛋白脂肪细胞脂肪酸结合蛋白(adipocyte fatty acid-binding protein,aP2)在非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)患者肝脏中的表达及意义。[方法]收集2011-01—2012-12期间收治的16例NAFLD患者(NAFLD组)及15例有轻度肝功能异常但肝穿病理检查正常者(对照组)的肝穿标本;对2组标本行苏木精-伊红染色和Masson染色了解其脂肪肝活动度评分,免疫荧光双标染色检测肝组织中aP2蛋白的表达定位,以及RT-PCR检测aP2基因的表达;对2组以上测定结果进行分析比较。[结果]病理组织学结果显示NAFLD组患者的脂肪变程度达到1~3级,肝小叶内炎症1~3级,肝细胞气球样变达0~1级,肝纤维化评分0~2。NAFLD组活动度评分5.3±1.25,对照组为0。在激光共聚焦显微镜下,可见NAFLD组绿色荧光标记的aP2表达于肝细胞胞浆内,并且与红色荧光标记的白蛋白位置重叠;对照组肝脏中无aP2表达。RTPCR显示NAFLD组肝脏组织aP2mRNA的表达较对照组升高了约3.3倍。[结论]在NAFLD时,肝细胞可以表达脂肪细胞特征性蛋白,即发生了成脂性改变,此改变与肝脏的炎症反应相关,可能参与了疾病的进展。     

Effects of estrogen and androgen deprivation on the progression of non-alcoholic steatohepatitis (NASH) in male Sprague–Dawley rats

Aim:  We studied the mechanisms of estrogen/androgen involvement in the induction of NASH by treating Sprague–Dawley (SD) rats fed with a normal or high fat (HF) diet by depriving them of endogenous estrogens/androgens.
Methods:  Male adult SD rats ( n  = 10/group) on normal or HF diets were treated for 75 days either with tamoxifen (Tam) or flutamide (Flu) or Tam + Flu in order to induce NASH. We analyzed histopathologically the liver samples from the treated groups for NASH, checked the serum biochemical and lipid profile markers and finally analyzed the signal pathways underlying the molecular mechanisms for the induction process of NASH.
Results:  Deprivation of endogenous estrogens and/or androgens (Tam or Flu or Tam + Flu) without the HF diet did not induce NASH. Tam or Tam + Flu induced NASH, compared to milder lesions without fibrosis in HF diet and Flu-treated liver. Serum alanine aminotransferase or lipid profile markers further proved the Tam, Flu or Tam + Flu effects on the induction of NASH in conjunction with a HF diet. Tam treatment predominantly downregulated the ERα and FAS and upregulated UCP2 and TNF-α.
Conclusions:  Deprivation of endogenous estrogen/androgens in conjunction with a HF diet may induce NASH where the downregulated ERα and FAS, and upregulated UCP2 and TNF-α could be involved in their molecular pathomechanism pathways. These results could suggest the potential negative roles of estrogenic/androgenic depriving compounds in the induction of NASH, along with obesity.     

Non-alcoholic steatohepatitis in type 2 diabetes mellitus

BACKGROUND AND AIMS: Non-alcoholic steatohepatitis (NASH) is commonly associated with type 2 diabetes mellitus (DM). Prevalence of NASH in type 2 DM has not been well studied and there is an epidemic rise in type 2 DM in Asian and Western populations. Its association with chronic liver disease in the form of NASH makes it an important health problem. Hence we have studied its prevalence and correlation of biochemical parameters with histological grades of non-alcoholic fatty liver disease (NAFLD) in otherwise asymptomatic type 2 DM patients. METHODS: One hundred and forty-eight individuals were screened. Forty-eight individuals were excluded due to history of alcohol intake or liver disease as a result of other causes. One hundred non-alcoholic individuals with type 2 DM underwent abdominal ultrasonography (US abdomen). Forty-nine patients had evidence of fatty liver on US abdomen, and 32 of these 49 patients underwent liver biopsy. RESULTS: Four of 32 (12.5%) individuals had steatosis alone. Mild, moderate and severe NASH was present in 21/32 (65.5%), 4/32 (12.5%) and 3/32 (9.35%), respectively. Fibrosis was present in 7/32 (21.8%) patients (four grade 1 and three grade 3). There was no significant difference in body mass index (BMI), transaminase levels, serum cholesterol and triglyceride levels among patients with non-alcoholic fatty liver disease. CONCLUSION: We conclude that the prevalence of NASH is high in type 2 DM patients and liver biopsy is the only investigation to differentiate between non-alcoholic fatty liver and steatohepatitis.     

非酒精性脂肪性肝病发生及进展的危险因素

非酒精性脂肪性肝病(NAFLD)的患病率逐年增加,目前成为我国成年人中最常见的慢性肝病之一。NAFLD可由非酒精性肝脂肪变性进展为非酒精性脂肪性肝炎、肝硬化、肝细胞癌及NAFLD相关性心血管事件、死亡等重大疾病。现对NAFLD发生的危险因素以及进展为肝纤维化、肝硬化、肝癌、相关心血管事件和死亡等重大疾病的相关危险因素进行综述,以便进一步探讨NAFLD发生发展的机制,降低NAFLD的患病率,减缓NAFLD的进展程度,降低相关疾病的病死率。     

非酒精性脂肪性肝病的诊断和治疗进展

随着非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)流行率的上升以及对其危害的全面认识,其诊断和治疗发展迅速。本文介绍了新的NAFLD病理学评分系统和病理学检查指征;在无创性诊断方面概述了肝脏脂肪变性、肝脏炎症和纤维化无创性诊断的现有方法及最新进展,以及疾病进展风险因素;在治疗方面,描述了饮食控制要点,并介绍了抗阻运动联合有氧运动和避免静坐的三联运动方式;在药物治疗方面,介绍了维生素E和吡格列酮2个重点药物的优缺点。最后,简述了以疾病分级为基础的检测和治疗策略。     

Non-alcoholic fatty liver disease in the Asia-Pacific region: definitions and overview of proposed guidelines

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western industrialized countries, affecting 20-40% of the general population. Large population-based surveys in China, Japan, and Korea indicate that the prevalence of NAFLD is now 12% to 24% in population subgroups, depending on age, gender, ethnicity, and location (urban versus rural). There is strong evidence that the prevalence of NAFLD has increased recently in parallel with regional trends in obesity, type 2 diabetes, and metabolic syndrome; and that further increases are likely. The relationship between NAFLD, central obesity, diabetes, and metabolic syndrome is clearly evident in retrospective and prospective Asian studies, but the strength of association with these metabolic risk factors is only appreciated when regional definitions of anthropometry are used. Pathological definition of NAFLD, particularly its activity and the extent of liver fibrosis, requires histological examination, but liver biopsy is often not appropriate in this disorder for logistic reasons. An alternative set of operational definitions is proposed here. Clinicians need guidelines as how best to diagnose and manage NAFLD and its associated metabolic disorders in countries with scant healthcare resources. The Asia-Pacific Working Party (APWP) for NAFLD was convened to collate evidence and deliberate these issues. Draft proposals were presented and discussed at Asia-Pacific Digestive Week at Cebu, Philippines, in late November 2006, and are published separately in this issue of the Journal as an Executive Summary. The present document reviews the reasoning and evidence behind the APWP-NAFLD proposals for definition, assessment, and management of NAFLD in the Asia-Pacific region.     

Commonly used animal models of non-alcoholic steatohepatitis

BACKGROUND:Animal models are an essential tool in non-alcoholic steatohepatitis (NASH) studies. Ideally, such models should reflect the etiology, disease progression, and the established pathology of human NASH. To date, no single animal model displays the range of histopathologic and pathophysiologic features associated with human NASH. The currently available models do not or only partially reflect the real picture of human NASH. In particular, insulin resistance and fibrosing steatohepatitis are rarely r...     

Current management of non‐alcoholic steatohepatitis

Non‐alcoholic steatohepatitis (NASH) is the most common cause of liver disease in Western populations, and its prevalence is increasing rapidly. It is part of a multisystem disease affecting other organs such as the kidneys, heart and blood vessels, and is closely associated with the components of the metabolic syndrome. Physicians managing patients with NASH should not only focus on the management of NASH, but also on associated comorbidities in individual patients. The approaches to treatment of NASH include either limiting energy surplus alone, or in combination with targeting of downstream pathways of inflammation and fibrosis. In this mini‐review, we discuss the currently available treatment options for NASH, as well as those in late‐stage clinical trials. We discuss the challenges of managing these patients with a limited number of approved therapies, as well as managing advanced‐stage patients with NASH and cirrhosis. We also discuss the specific management of comorbidities in NASH patients, in particular diabetes, hypertension, dyslipidaemia and cardiovascular diseases. Finally, we present the screening protocols for both hepatocellular carcinoma and extrahepatic malignancies in these patients.     

非酒精性脂肪性肝病肝纤维化的诊断和治疗进展

非酒精性脂肪性肝病(NAFLD)正成为全球最常见的慢性肝病。从其疾病谱来看,非酒精性脂肪性肝炎(NASH)是疾病进展形式,可进展为肝纤维化,从而导致NAFLD相关肝硬化和肝癌。NASH肝纤维化与疾病预后密切相关,临床亟需有效措施诊断及干预疾病进展。重点介绍了目前非酒精性脂肪性肝纤维化的诊断和治疗进展。     

肝血窦内皮细胞在非酒精性脂肪性肝病发展中的作用

非酒精性脂肪性肝病(NAFLD)是以肝脏脂肪变、炎症和纤维化为主要表现的临床代谢综合征,日渐成为严重影响公众健康的常见慢性肝病。肝血窦内皮细胞(LSEC)是肝脏组织特化的血管内皮细胞,作为一道重要的血管屏障,其对肝脏细胞吸收和代谢源自肠道血液中的营养与物质成分发挥重要调节作用。介绍了NAFLD发生发展进程中LSEC毛细血管化、血管功能障碍及其参与调控肝脏炎症、血管生成、肝纤维化的研究进展。     

非酒精性脂肪性肝病与代谢综合征相关性的临床研究

目的分析非酒精性脂肪性肝病与代谢综合征的关系。方法按住院顺序选择有随访资料病例共185例,将其分为四组（单纯脂肪肝组、单纯肥胖组、脂肪肝＋肥胖组、正常对照组）,在基线水平对四组出现代谢综合征情况进行横向比较。其次,在随访后再次对四组出现代谢综合征情况进行组内、组间比较。结果随访结束时,单纯脂肪肝组代谢综合征发病率明显高于正常对照组（P〈0.05）。结论非酒精性脂肪性肝病促进代谢综合征的发生,且不依赖于肥胖。