固醇调节元件结合蛋白与非酒精性脂肪性肝病

固醇调节元件结合蛋白(SREBP)是新发现的螺旋-环-螺旋-亮氨酸链转录因子家族的一员,合成后以无活性的前体形式结合在内质网上,细胞内胆固醇的含量通过反馈抑制蛋白水解加工过程而控制SREBP的激活。SREBP与肝脏脂质代谢紊乱、胰岛素抵抗、过氧化物酶体增殖物激活受体、氧化应激、肝脏X受体和解偶联蛋白2等有关,在非酒精性脂肪性肝病发病过程中起着重要作用。     

Histopathology of nonalcoholic fatty liver disease

Histological analysis of liver biopsies remains a standard against which other methods of assessment for the presence and amount of hepatic injury due to nonalcoholic fatty liver disease(NAFLD) are measured.Histological evaluation remains the sole method of distinguishing steatosis from advanced forms of NAFLD,i.e.nonalcoholic steatohepatitis(NASH) and fibrosis.Included in the lesions of NAFLD are steatosis,lobular and portal inflammation,hepatocyte injury in the forms of ballooning and apoptosis,and fibros...     

Promising diagnostic biomarkers of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: From clinical proteomics to microbiome

Fatty liver has been present in the lives of patients and physicians for almost two centuries. Vast knowledge has been generated regarding its etiology and consequences, although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is still envisioned. On the one hand, proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis. In contrast, metabolomics has been able to distinguish between NAFLD and NASH, even detecting degrees of fibrosis. On the other hand, genetic and epigenetic markers have been useful in monitoring disease progression, eventually functioning as target therapies. Other markers involved in immune dysregulation, oxidative stress, and inflammation are involved in the instauration and evolution of the disease. Finally, the fascinating gut microbiome is significantly involved in NAFLD and NASH. This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease. As is evident, despite great advances in studying these biomarkers, there is still a long path before they translate into clinical benefits.     

Dietary habits and behaviors associated with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD)is one of the most frequent causes of health problems in Western(industrialized)countries.Moreover,the incidence of infantile NAFLD is increasing,with some of these patients progressing to nonalcoholic steatohepatitis.These trends depend on dietary habits and life-style.In particular,overeating and its associated obesity affect the development of NAFLD.Nutritional problems in patients with NAFLD include excess intake of energy,carbohydrates,and lipids,and shortages of polyunsaturated fatty acids,vitamins,and minerals.Although nutritional therapeutic approaches are required for prophylaxis and treatment of NAFLD,continuous nutrition therapy is difficult for many patients because of their dietary habits and lifestyle,and because the motivation for treatment differs among patients.Thus,it is necessary to assess the nutritional background and to identify nutritional problems in each patient with NAFLD.When assessing dietary habits,it is important to individually evaluate those that are consumed excessively or insufficiently,as well as inappropriate eating behaviors.Successful nutrition therapy requires patient education,based on assessments of individual nutrients,and continuing the treatment.In this article,we update knowledge about NAFLD,review the important aspects of nutritional assessment targeting treatment success,and present some concrete nutritional care plans which can be applied generally.     

脂肪肝指数在非酒精性脂肪性肝病诊断中的应用价值

目的:通过评估脂肪肝指数(FLI),探讨其对非酒精性脂肪性肝病(NAFLD)的筛查和诊断价值。方法:选取年龄大于40岁的上海嘉定地区常住居民共2 519人,通过问卷调查、体格检查及相关人体测量学和生化学指标检测,综合评估人群代谢状态并计算个体FLI。通过高分辨率超声诊断NAFLD。利用受试者工作特征(ROC)曲线评估FLI对于经超声诊断的NAFLD的预测价值。结果:最终共有2 139名受试者纳入统计分析。FLI作为诊断NAFLD的ROC曲线下面积为0.84,95%可信区间为0.82～0.86。当FLI≥30时,其诊断NAFLD的敏感性和特异性最好,灵敏度和特异度分别达到80.6%和73.8%。结论:FLI对于NAFLD的诊断具有较高的参考价值,适用于大样本流行病学研究及指导NAFLD的早期干预和治疗。     

性激素在非酒精性脂肪性肝病发病机制中的作用

非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)是一类由遗传-环境-代谢应激相关因素所致的,以弥漫性肝细胞大泡性脂肪变性和肝小叶内炎症为主要特征的临床病理综合征.近年来,随着研究深入,发现NAFLD不仅与肝脏脂质代谢紊乱、胰岛素抵抗(insulin resistance,IR)、氧化应激、内毒素血症等相关,其发生还存在明显性别差异,推测其可能与不同性别间性激素水平、肝脂代谢差异以及糖脂代谢酶表达及活性差异等多种因素相关[1].现结合近年来国内外最新文献,就性激素在NAFLD患者中的变化及其对NAFLD发病的影响和作用机制作一简要综述. 一、NAFLD流行病学与性别差异 Hepatology于2011年发表了澳大利亚一项最新研究结果,1170例青少年中,NAFLD发病率为12.8％,其中男女比例约为1:1.6[2].该结论与多项国内外研究结果显示的男性脂肪肝患病率高于女性相悖,分析其原因可能与不同研究人口基础特征、ALT水平及不同性别人群肥胖比例差异等相关[3].有关NAFLD性别差异的研究结果显示,整体人群中,男性NAFLD患者高于女性,但青春期前及50岁以后女性发病率明显高过男性,说明女性激素可能对生育期女性脂肪肝的发生起保护作用.     

Treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause for elevated liver enzymes in the developed nations. Beyond prevention programs which are of particular interest because of the increasing number of overweight children, treatment should be focussed on the most important risk factors, obesity and insulin resistance. As a consequence of elucidating the pathomechanisms of NAFLD, the number of potential therapeutic options increased. However, many studies investigating the therapeutic effect show shortcomings in at least one of the following points: lack of a serial liver biopsy, short term of treatment and limited number of included patients. The second generation insulin sensitizer piogiitazone and rosiglitazone show the most promising improvements in NAFLD, but weight gain and potential hepatotoxicity calls for attention. In conclusion, a general recommendation for the application of specific drugs cannot be given. Besides controlled clinical trials, weight reduction and physical activity to improve insulin sensitivity in obese patients should be the priority objective.     

非酒精性脂肪性肝病小鼠肝组织与脂质代谢相关基因FAS、ACC和SREBP-1水平分析*

目的 探讨非酒精性脂肪性肝病(NAFLD)小鼠肝组织脂质代谢相关基因水平变化。方法 采用高脂饲料喂养20小鼠,构建小鼠NAFLD动物模型,观察小鼠肝组织病理学变化,检测血清总胆固醇(TCH) 和甘油三酯(TG)含量,采用RT-PCR法检测小鼠肝组织胆固醇调节元件结合蛋白(SREBPs)、乙酰辅酶A羧化酶(ACC)和脂肪酸合成酶(fatty acid synthase, FAS)基因变化。结果 10只NAFLD模型小鼠肝细胞排列不整齐,肝细胞内出现大小不等的脂滴;NAFLD模型小鼠血清TG和TCH水平分别为(0.63±0.13)mmol/L和(7.23±0.7)mmol/L,显著高于10只对照组[(0.28±0.06)mmol/L和(2.78±0.6)mmol/L,P<0.001];在实验24 w末,NAFLD组小鼠肝组织FAS 和SREBP-1 mRNA水平分别为(3.9±1.1)和(1.8±0.7),对照组则分别为【(1.0±0.3)和(1.0±0.4),FAS: t = 6.231, P<0.001; SREBP-1: t =2.431, P =0.035】,差异显著,而NAFLD组小鼠肝组织ACC mRNA水平为(1.2±0.5),与对照组【(1.0±0.4), t=0.765, P=0.462】比,无显著差异。结论 NAFLD模型小鼠肝组织与脂质代谢相关基因显著上调,为进一步研究NAFLD的发生发展机制奠定了基础。     

Review of nonalcoholic fatty liver disease in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women. Women with PCOS frequently have metabolic complications including insulin resistance (IR), early diabetes, hypertension and dyslipidemia. Recent studies have demonstrated an association between PCOS and another metabolic complication: nonalcoholic fatty liver disease (NAFLD). NAFLD occurs as a result of abnormal lipid handling by the liver, which sensitizes the liver to injury and inflammation. It can progress to nonalcoholic steatohepatitis (NASH), which is characterized by hepatocyte injury and apoptosis. With time and further inflammation, NASH can progress to cirrhosis. Thus, given the young age at which NAFLD may occur in PCOS, these women may be at significant risk for progressive hepatic injury over the course of their lives. Many potential links between PCOS and NAFLD have been proposed, most notably IR and hyperandrogenemia. Further studies are needed to clarify the association between PCOS and NAFLD. In the interim, clinicians should be aware of this connection and consider screening for NAFLD in PCOS patients who have other metabolic risk factors. The optimal method of screening is unknown. However, measuring alanine aminotransferase and/or obtaining ultrasound on high-risk patients can be considered. First line treatment consists of lifestyle interventions and weight loss, with possible pharmacologic interventions in some cases.     

Probiotics as a complementary therapeutic approach in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD) is currently recognized as one of the most common causes of chronic liver disease. It involves a spectrum of conditionsthat include pure steatosis without inflammation, steatohepatitis, fibrosis and cirrhosis. The key factor in the pathophysiology of NAFLD is insulin resistance that determines lipid accumulation in the hepatocytes and, thus, oxidative stress, which is followed by inflammatory response. However, NAFLD pathogenesis is still largely unknown and has been extensively investigated. Although life style modification with the aim of losing weight has been advocated to treat this disorder, its effectiveness is limited; additionally, there is no specific pharmacologic treatment until nowadays. Recent evidence suggests that the gut microbiota may play a role in the development of insulin resistance, hepatic steatosis, necroinflammation and fibrosis. Differences in gut microbiota between NAFLD patients and lean individuals as well as presence of small intestinal bacterial overgrowth in NAFLD subjects have been demonstrated. Furthermore, some data indicate that the immunoregulatory effects of probiotics may be beneficial in NAFLD treatment as they modulate the intestinal microbiota; improve epithelial barrier function and strengthen the intestinal wall decreasing its permeability; reduce bacterial translocation and endotoxemia; improve intestinal inflammation; and reduce oxidative and inflammatory liver damage. In this article, we review the clinical trials on the use of probiotics in the treatment of NAFLD and discuss the effects of these agents and their efficacy as an emerging therapeutic resource to treat NAFLD patients.     

高脂饮食非酒精性脂肪性肝病大鼠肝脏成脂相关基因表达增强

目的探讨非酒精性脂肪性肝病（NAFLD）大鼠肝脏成脂相关基因mRNA表达的动态变化.方法模型组SD大鼠给予高脂饮食饲养,分批于实验第4、8、12、16、24周处死,同期设普通饮食饲养大鼠作对照.RT-PCR分别检测肝脏固醇调节元件结合蛋白1c（SREBP-1c）及其靶基因脂肪酸合成酶（FAS）、脂联素、抵抗素mRNA表达.结果模型组大鼠4周肝脏可见散在性肝细胞脂肪变性,8周为单纯性脂肪性肝炎,12～24周从脂肪性肝炎进展为脂肪性肝炎伴肝纤维化.从实验第4周起,模型组大鼠肝脏SREBP-1c和FAS mRNA表达逐渐增强,至24周时分别较对照组升高5～6倍和2～2.5倍;模型组大鼠肝脏从第12周起出现脂联素和抵抗素mRNA表达,两者表达量均随造模时间延长而增强.相关分析显示,SREBP-1c、FAS、脂联素、抵抗素mRNA表达量均与肝脂肪变程度呈正相关（r值分别为0.808、0.834、0.592、0.577,P值均＜0.01）.结论高脂饮食NAFLD大鼠肝脏SREBP-1c、FAS、脂联素、抵抗素等成脂基因表达增强,提示脂肪变性的肝细胞可能部分具有脂肪细胞的特征,即发生了成脂性改变.     

Transition of an acronym from nonalcoholic fatty liver disease to metabolic dysfunction-associated fatty liver disease

Nonalcoholic fatty liver disease(NAFLD) is a global public health concern owing to its substantial contribution to chronic liver diseases. The disease is closely linked to metabolic syndrome(MS), suggesting a common biological pathway and shared disease mechanism for both ailments. Previous studies revealed a close relationship of NAFLD with the components of MS including abdominal obesity,dyslipidemia, hypertension, and hyperglycemia. Hence, a group of experts recently renamed NAFLD as metabolic dysfunction-associated fatty liver disease(MAFLD) in order to encompass a more appropriate pathogenesis of the disease.NAFLD was first named to describe a condition similar to alcoholic hepatitis in absence of significant alcohol consumption. However, knowledge pertaining to the etiopathogenesis of the disease has evolved over the past four decades. Recent evidence endorses NAFLD as a terminology of exclusion and suggests that it may often leads to misdiagnosis or inappropriate management of patients, particularly in clinical practice. On the other hand, the new definition is useful in addressing hepatic steatosis with metabolic dysfunction, which ultimately covers most of the patients with such illness. Therefore, it seems to be helpful in improving clinical diagnosis and managing high-risk patients with fatty liver disease. However, it is imperative to validate the new terminology at the population level to ensure a holistic approach to reduce the global burden of this heterogeneous disease condition.     

饮食干预对非酒精性脂肪性肝病肠道菌群的影响

非酒精性脂肪性肝病(NAFLD)的发生与遗传和环境密切相关,肠道菌群在其发生和发展中发挥了重要作用,调节肠道菌群已成为干预NAFLD的重要靶点之一.无论是饮食总量还是结构都会对肠道菌群产生直接且长期的影响.通过低脂饮食、增加饮食中不饱和脂肪酸或者增加难以吸收的多糖等方式调整饮食结构,可以有效调节肠道菌群并治疗NAFLD,但高蛋白饮食的作用还存在争议.     

Inhibition of apoptosis in the management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in the developed world. The pathogenesis of NAFLD is multifactorial, involving obesity, insulin resistance, inflammation and oxidative stress. Accordingly, several treatments targeting these pathways have been evaluated in patients with NAFLD but have either shown limited efficacy or an unfavorable safety profile. On the other hand, increased hepatocyte apoptosis also appears to be implicated in the development and progression of NAFLD and recent pilot studies suggest that inhibition of apoptosis might represent a useful approach in this disease. However, several issues pertaining both to the efficacy and safety of this new class of agents remain unresolved and larger studies are required to clarify the role of this therapeutic modality in the management of NAFLD.     

Advances in paediatric nonalcoholic fatty liver disease: Role of lipidomics

Due its close relationship with obesity, nonalcoholic fatty liver disease (NAFLD) has become a major worldwide health issue even in childhood. The most accepted pathophysiological hypothesis is represented by the “multiple hits” theory, in which both hepatic intracellular lipid accumulation and insulin resistance mainly contribute to liver injury through several factors. Among these, lipotoxicity has gained particular attention. In this view, the pathogenic role of different lipid classes in NAFLD (e.g., sphingolipids, fatty acids, ceramides, etc.) has been highlighted in recent lipidomics studies. Although there is some contrast between plasma and liver findings, lipidomic profile in the NAFLD context provides novel insights by expanding knowledge in the intricate field of NAFLD pathophysiology as well as by suggesting innovative therapeutic approaches in order to improve both NAFLD prevention and treatment strategies. Selective changes of distinct lipid species might be an attractive therapeutic target for treating NAFLD. Herein the most recent evidence in this attractive field has been summarized to provide a comprehensive overview of the lipidomic scenario in paediatric NAFLD.     

肠道益生菌对非酒精性脂肪肝的影响

目的探讨肠道菌群与非酒精性脂肪肝(NAFLD)的关系。方法对53例服用肠道益生菌的NAFLD患者和56例对照组患者进行服药前后肝脏的超声检查,抽血查血肌酐、尿素氮、总胆固醇、三酰甘油、空腹血糖,并同时对年龄和体质量指数(BMI)进行统计。结果服药前两组各项指标比较,差异无统计学意义(P0.05)。服药后肠道益生菌组和对照组比较,脂肪肝消退数明显增加,差异有统计学意义(P0.05)。服药前后两组比较,肠道益生菌组服药后较服药前脂肪肝消退数明显增加,差异有统计学意义(P0.01);而对照组各项指标比较,差异均无统计学意义(P0.05)。两组服药前后各种观察指标差值的比较,脂肪肝消退、中度脂肪肝减少数、总胆固醇、三酰甘油和尿素氮下降在肠道益生菌组差异有统计学意义(P0.05、P0.01)。结论口服益生菌可以降低NAFLD的发生,益生菌可能具有预防和治疗NAFLD的作用。     

Histopathology of nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD), a hepatic manifestation of metabolic syndrome, is the most common chronic liver disease, and the prevalence is rapidly increasing worldwide. Nonalcoholic steatohepatitis (NASH), the severe form of NAFLD, can progress to liver cirrhosis and hepatocellular carcinoma (HCC). Although noninvasive clinical scores and image-based diagnosis for NAFLD have improved, histopathological evaluation of biopsy specimens remains the gold standard for diagnosing NAFLD/NASH. Steatosis, lobular inflammation, and hepatocellular ballooning are all necessary components for the diagnosis of NASH; fibrosis is also typically observed. Other histopathological abnormalities commonly observed in NASH include hepatocellular glycogenated nuclei, lipogranulomas, and acidophil bodies. The characteristics of pediatric NAFLD/NASH differ from adult NAFLD/NASH. Specifically, steatosis and portal inflammation are more severe in pediatric NAFLD, while intralobular inflammation and perisinusoidal fibrosis are milder. Although interobserver agreement for evaluating the extent of steatosis and fibrosis is high, agreement is low for intralobular and portal inflammation. A recently reported histological variant of HCC, steatohepatitic HCC (SH-HCC), shows features that resemble non-neoplastic steatohepatitis, and is thought to be strongly associated with underlying NASH. In this report, we review the histopathological features of NAFLD/NASH.     

非酒精性脂肪性肝病的相关危险因素研究进展

非酒精性脂肪性肝病(NAFLD)是指一群组织病理异常,其发病以胰岛素抵抗为基础,并与肥胖、高脂血症、Ⅱ型糖尿病、原发性高血压等密切相关。疾病早期症状隐匿,如不及时控制可诱发肝硬化及慢性肝病。NAFLD治疗策略有限,因此探讨脂肪肝相关危险因素对降低NAFLD发病及延缓其病程进展具有重要意义。     

Nonalcoholic steatohepatitis in nonalcoholic fatty liver disease patients of Bangladesh

AIM: To explore the prevalence and risk factors for nonalcoholic steatohepatitis (NASH) in nonalcoholic fatty liver disease (NAFLD) patients. METHODS: We have included 493 patients with sonographic evidence of a fatty change, and 177 of these individuals were evaluated and confirmed after liver biopsy. The exclusion criteria consisted of significant alcohol abuse (< 20 g daily), evidence of hepatitis B and C, evidence of drug-induced fatty liver disease and other specific liver diseases such as hemochromatosis, Wilson’s disease or autoimmune liver disease. The patients were assessed for metabolic syndrome, and biochemical, anthropometric and histopathological evaluations were carried out. The degree of disease activity in the NAFLD patients was evaluated using the NAFLD Activity Score. The data were analyzed by SPSS, version 16.0. RESULTS: Females predominated among the study participants (250, 57.0%), and the mean age was 40.8 ± 10.2 years. The numbers of overweight, obeseⅠ and obese Ⅱ patients were 58 (13.2%), 237 (53.9%) and 93 (21.2%), respectively. However, there were 422 (96.2%) centrally obese patients. NASH was absent in 10 (5.6%) cases, borderline in 92 (52.6%) cases and present in 75 (42.4%) cases. The presence of diabetes could significantly (P = 0.001) differentiate NASH from simple steatosis. The following parameters did not influence the development of NASH: age, sex, basal metabolic index, waist circumference, serum high-density lipoprotein, triglyceride, insulin resistance index, hypertension and metabolic syndrome. The serum gammaglutamyl transpeptidase (GGT) level was significantly higher (P = 0.05, 51.7 ± 32.8 and 40.4 ± 22.6 U/L) in the NASH patients, with a sensitivity of 45% and a specificity of only 68%. The serum alanine aminotransferase and aspartate aminotransferase levels were not able to predict NASH. CONCLUSION: Females were the predominant sufferers of NAFLD in Bangladesh. The prevalence of NASH was high. Diabetes was found to be the main culprit in developing NASH. GGT was the only biochemical marker of NASH. We recommend liver biopsy in NAFLD patients who have diabetes and elevated GGT.