慢性丙型肝炎肝细胞及细胞器病变特点研究

目的观察不同炎症程度的丙型肝炎肝细胞及细胞器超微结构,了解不同炎症程度的丙型肝炎患者肝细胞超微结构特征。方法收集6例经肝穿刺活检病理确诊的轻度、中度、重度丙型肝炎肝组织标本各2例,同时选取2例肝移植中的正常供肝组织作为对照,对照光镜特点,对各病例电镜下的肝细胞器超微结构特点进行分析总结。结果光镜下观察到轻度慢性丙型肝炎以肝细胞水肿变性为主;中度慢性丙型肝炎以汇管区炎症为主伴淋巴滤泡形成;重度慢性丙型肝炎肝小叶内易见肝细胞点状坏死,纤维组织增生并可见弓形纤维或假小叶形成。电镜下观察到与正常肝细胞相比较,轻度慢性丙型肝炎病例中肝细胞胞浆内粗面内质网减少、滑面内质网增多;中度慢性丙型肝炎表现为肝细胞胞浆内脂滴稍增多,部分伴脂滴融合,胞浆内局灶可见胶原纤维;而重度慢性丙型肝炎的肝细胞内可见线粒体凝聚、融合和变性,糖原增多,脂滴进一步呈大泡型脂变并融合,细胞核内可见包涵体形成。结论不同炎症程度的丙型肝炎肝细胞具有不同的超微结构特征。     

非酒精性脂肪肝炎动物模型的研究概况

随着全球代谢综合征患病率不断上升,非酒精性脂肪肝病(NAFLD)患病率也急剧上升,已是全球最常见的慢性肝疾病,包括单纯性脂肪肝、非酒精性脂肪性肝炎(NASH)、晚期纤维化、肝硬化和肝细胞癌。而NASH是由单纯性脂肪肝发展至肝纤维化、肝硬化和肝癌的重要阶段,因此,预防和治疗NASH已成为一个研究焦点。动物模型是研究疾病的发病机制、治疗药物的研发以及制定防治策略的重要环节。目前已经开发的动物模型主要是模拟人类NASH的病理形态和临床特征,包括膳食动物模型、药物诱导动物模型和基因修饰动物模型,但这些模型均存在各自的优缺点。本文就近年来NASH动物模型的研究及其应用情况进行总结,以供NASH研究者参考。     

肠道菌群与非酒精性脂肪肝相关性的研究进展

非酒精性脂肪肝(NAFLD)是我国最常见的慢性肝病之一,为非酒精性因素所致的肝细胞脂肪变为特征的综合征,包括单纯性脂肪肝(SFL)、非酒精性脂肪性肝炎(NASH)及其相关肝硬化和肝细胞癌(HCC)。人体肠道中的各种菌群发挥着不同的病理生理作用,与许多疾病密切相关,肠道菌群可以通过"肠-肝轴"影响NAFLD的发生发展,"二次打击"学说很好地解释了NAFLD的发病机制及其与肠道菌群的关系。益生元、益生菌可以很好地调节肠道菌群,与抗生素和手术相比更加廉价、无害、安全,有望成为预防和治疗NAFLD的新方法。本研究对肠道菌群与NAFLD相关性的研究进展加以综述。     

非酒精性脂肪肝发病机制和治疗的研究进展

非酒精性脂肪性肝病(non-alcoholic fatty liver disease, NAFLD)已成为全球最常见肝病之一,其发病率仍然有继续增加的趋势。NAFLD是一类包含单纯性脂肪肝、非酒精性脂肪性肝炎(non-alcoholic steatohepatitis, NASH)等疾病的临床病理综合征,并可能进一步进展为肝硬化、肝衰竭和肝细胞性肝癌,威胁人类健康。目前NAFLD的发病机制尚不完全清楚,并且尚没有理想的有效治疗药物。该文主要就NAFLD的发病机制和治疗的研究进展进行综述,为NAFLD的基础研究和临床治疗提供相关的参考。     

Visfatin在非酒精性脂肪性肝病发展过程中的表达及意义

观察血清及肝脏组织中内脂素(Visfatin)的表达情况,探讨其在非酒精性脂肪性肝病(nonalcoholic fattyliver disease,NAFLD)发生、发展过程中的作用.以高脂饮食构建NAFLD大鼠模型,应用酶联免疫吸附法、RT-PCR及免疫组织化学等方法,动态检测大鼠NAFLD发展过程中血清Visfatin的含量及其在肝组织中的表达.结果显示:在模型组大鼠由单纯性脂肪肝(SS)发展为非酒精性脂肪性肝炎(NASH)的过程中,Visfatin在大鼠血清和肝组织中的表达均呈现由高到低的变化趋势,SS组大鼠Visfatin的表达显著高于正常对照组和NASH组(P<0.01),而正常对照组和NASH组之间无明显差异;SS组大鼠Visfatin主要表达于小叶中央静脉周围脂肪变性相对较轻的肝细胞内.由此认为,Visfatin在血清和肝组织中的高表达作为早期事件,可能在NAFLD发展过程中起重要作用.     

Gilbert 综合征肝活检的超微结构特征*

目的:确定Gilbert综合征患者肝组织的超微结构特征,为Gilbert综合征的诊断和鉴别诊断提供新的方法。方法:按电镜常规进行标本制备,应用透射电镜对20例Gilbert综合征患者肝穿刺活检组织进行超微结构观察。结果:肝细胞可出现巨大线粒体,常含有副晶格样包涵体、较明显的基质致密颗粒。肝细胞常见脂褐素颗粒增多,多分布于毛细胆管周围肝细胞内。可出现较有特征性的色素颗粒,大小不等,卵圆形或不规则形,含有电子致密块状颗粒,与电子密度略低的聚集物以及脂滴互相混杂。这些溶酶体颗粒的基质由细小的、弱嗜锇性的颗粒组成。少数颗粒类似Dubin-Johnson综合征的颗粒。但颗粒较小,缺少致密核芯结构。结论:特征性的含粗大电子致密物的溶酶体对Gilbert综合征的诊断有重要参考价值。     

模拟人类非酒精性肝病的小鼠模型

<正>非酒精性脂肪肝病(nonalcoholic fatty liver disease,NAFLD)为当前全球最常见慢性肝病,且呈低龄化趋势,其俗称为"脂肪肝";其病理特征,为肝细胞脂肪变性;其病因,可排除酗酒史及其他肝病因素;其发病率高,西方国家达15%~30%,我国达15%;该病初期,为单纯性脂肪肝(nonalcoholic simple fatty liver,NAFL)病情较稳定;然而,如发展到脂肪性肝炎(nonalcoholic steatohepatitis,NASH),则可进一步恶变为肝硬化、肝癌;脂肪性肝炎患病10~15年肝硬化率达15%~25%,其中约30%~     

肠道菌群影响非酒精性脂肪性肝病的机制及应对策略

非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)的发病率逐年升高,已成为最常见的肝脏疾病之一。目前其发病机制未被完全阐明,尚无有效治疗药物。肠道菌群与人体共生,作为人体的“第二基因组”,其在消化、吸收及代谢中发挥重要作用。新近研究表明,肠道菌群已成为影响NAFLD发生、进展的重要因素,肠道菌群失调和肠肝轴紊乱与非酒精性单纯性脂肪肝(nonalcoholic fatty liver,NAFL)发展为非酒精性脂肪性肝炎(nonalcoholic steatohepatitis,NASH)、肝纤维化和肝细胞癌(hepatocellular carcinoma,HCC)密切相关。因此,肠道微生态干预有望成为预防或治疗NAFLD的新手段。本综述主要探讨肠道菌群异常对NAFLD/NASH发病过程、机制的影响及干预措施。     

PNPLA3在实验性非酒精性脂肪性肝病中的表达及其CpG岛甲基化状态的研究

目的:探讨PNPLA3在非酒精性脂肪性肝病中的表达水平及其Cp G岛甲基化状态,探讨PNPLA3在NAFLD发生、发展中的作用。方法:1.采用10μg/m L的油酸作用于人正常肝细胞株L02建立脂肪肝细胞模型,72 h后经油红O染色,观察正常组、脂肪肝模型组及给药组细胞内脂滴形成情况,并用荧光定量PCR检测PNPLA3在三组肝细胞中的表达情况。2.采用专用DNA提取试剂盒分别提取正常组、脂肪肝模型组、给药组细胞中DNA,经亚硫酸转化后行PCR扩增目的基因,并用焦磷酸测序方法检测不同组PNPLA3 Cp G岛中甲基化水平,探讨其在非酒精性脂肪肝中的作用。结果:1、脂肪肝模型组肝细胞PNPLA3 m RNA的表达高于正常组,经姜黄素给药后,其表达降低,差异均有统计学意义(P0.05)。2、在PNPLA3启动子区6个检测位点中,脂肪肝组位点2甲基化水平高于正常组,姜黄素给药后甲基化水平降低,差异均有统计学意义(P0.05),在其余各检测位点中甲基化水平无差异。结论:1、油红O染色后,脂肪肝模型组细胞内发现有大量红色脂滴积聚,而正常组基本上未见脂滴,姜黄素给药组脂滴较模型组减少,表明用10μg/m L的油酸诱导能成功建立体外肝细胞模型。2、PNPLA3 m RNA在肝细胞中高表达及其启动子区甲基化状态异常参与非酒精性脂肪肝发病。3、抑制肝脏PNPLA3活性或降低肝细胞PNPLA3 m RNA的表达水平可能是今后治疗非酒精性脂肪性肝病(NAFLD)的一个新的治疗方法。     

固醇调节元件结合蛋白2信号通路与非酒精性脂肪性肝病北大核心CSCD

非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)是以肝细胞内甘油三酯和胆固醇等脂毒性脂肪过度沉积为主要特征的一种临床获得性代谢综合征。最新研究表明,NAFLD向非酒精性脂肪肝炎(NASH)进展时,肝内胆固醇积累可能较甘油三酯更具有细胞毒性风险。固醇调节元件结合蛋白2(sterol regulatory element-binding protein 2,SREBP2)是脂质代谢重要的核转录因子之一,主要调控胆固醇的生物合成和体内平衡。SREBP2及其靶基因调控的胆固醇异常是引起非酒精性脂肪肝病发生发展的重要因素之一。因此,认识SREBP2信号通路中,上下游各因素的表达调控作用与NAFLD发病机制之间关系,就显得非常重要。本文总结了受SREBP2调控表达的靶基因的特点,着重介绍SREBP2调控胆固醇体内合成与平衡的信号通路与NAFLD发病机制之间关系,为研究和指导治疗NAFLD及其代谢性疾病提供新的思路。     

Increased Circulating Levels of Alpha-Ketoglutarate in Morbidly Obese Women with Non-Alcoholic Fatty Liver Disease

BackgroundNon-alcoholic fatty liver disease (NAFLD) causes a wide spectrum of liver damage, ranging from simple steatosis to cirrhosis. However, simple steatosis (SS) and steatohepatitis (NASH) cannot yet be distinguished by clinical or laboratory features. The aim of this study was to assess the relationship between alpha-ketoglutarate and the degrees of NAFLD in morbidly obese patients.ResultsWe found that serum levels of alpha-ketoglutarate were significantly higher in morbidly obese women than in normal-weight women. We showed that circulating levels of alpha-ketoglutarate were lower in lean controls and morbidly obese patients without NAFLD. We also found that alpha-ketoglutarate serum levels were higher in both SS and NASH than in normal liver of morbidly obese patients. However, there was no difference between SS and NASH. Moreover, we observed that circulating levels of alpha-ketoglutarate were associated with glucose metabolism parameters, lipid profile, hepatic enzymes and steatosis degree. In addition, diagnostic performance of alpha-ketoglutarate has been analyzed in NAFLD patients. The AUROC curves from patients with liver steatosis exhibited an acceptable clinical utility. Finally, we showed that the combination of biomarkers (AST, ALT and alpha-ketoglutarate) had the highest accuracy in diagnosing liver steatosis.ConclusionThese findings suggest that alpha-ketoglutarate can determine the presence of non-alcoholic fatty liver in morbidly obese patients but it is not valid a biomarker for NASH.     

Multi-SNP Analysis of GWAS Data Identifies Pathways Associated with Nonalcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease; the histological spectrum of which ranges from steatosis to steatohepatitis. Nonalcoholic steatohepatitis (NASH) often leads to cirrhosis and development of hepatocellular carcinoma. To better understand pathogenesis of NAFLD, we performed the pathway of distinction analysis (PoDA) on a genome-wide association study dataset of 250 non-Hispanic white female adult patients with NAFLD, who were enrolled in the NASH Clinical Research Network (CRN) Database Study, to investigate whether biologic process variation measured through genomic variation of genes within these pathways was related to the development of steatohepatitis or cirrhosis. Pathways such as Recycling of eIF2:GDP, biosynthesis of steroids, Terpenoid biosynthesis and Cholesterol biosynthesis were found to be significantly associated with NASH. SNP variants in Terpenoid synthesis, Cholesterol biosynthesis and biosynthesis of steroids were associated with lobular inflammation and cytologic ballooning while those in Terpenoid synthesis were also associated with fibrosis and cirrhosis. These were also related to the NAFLD activity score (NAS) which is derived from the histological severity of steatosis, inflammation and ballooning degeneration. Eukaryotic protein translation and recycling of eIF2:GDP related SNP variants were associated with ballooning, steatohepatitis and cirrhosis. Il2 signaling events mediated by PI3K, Mitotic metaphase/anaphase transition, and Prostanoid ligand receptors were also significantly associated with cirrhosis. Taken together, the results provide evidence for additional ways, beyond the effects of single SNPs, by which genetic factors might contribute to the susceptibility to develop a particular phenotype of NAFLD and then progress to cirrhosis. Further studies are warranted to explain potential important genetic roles of these biological processes in NAFLD.     

Genome-Wide Analysis of Copy Number Variation Identifies Candidate Gene Loci Associated with the Progression of Non-Alcoholic Fatty Liver Disease

Between 10 and 25% of individuals with non-alcoholic fatty liver disease (NAFLD) develop hepatic fibrosis leading to cirrhosis and hepatocellular carcinoma (HCC). To investigate the molecular basis of disease progression, we performed a genome-wide analysis of copy number variation (CNV) in a total of 49 patients with NAFLD [10 simple steatosis and 39 non-alcoholic steatohepatitis (NASH)] and 49 matched controls using high-density comparative genomic hybridization (CGH) microarrays. A total of 11 CNVs were found to be unique to individuals with simple steatosis, whilst 22 were common between simple steatosis and NASH, and 224 were unique to NASH. We postulated that these CNVs could be involved in the pathogenesis of NAFLD progression. After stringent filtering, we identified four rare and/or novel CNVs that may influence the pathogenesis of NASH. Two of these CNVs, located at 13q12.11 and 12q13.2 respectively, harbour the exportin 4 (XPO4) and phosphodiesterase 1B (PDE1B) genes which are already known to be involved in the etiology of liver cirrhosis and HCC. Cross-comparison of the genes located at these four CNV loci with genes already known to be associated with NAFLD yielded a set of genes associated with shared biological processes including cell death, the key process involved in ‘second hit’ hepatic injury. To our knowledge, this pilot study is the first to provide CNV information of potential relevance to the NAFLD spectrum. These data could prove invaluable in predicting patients at risk of developing NAFLD and more importantly, those who will subsequently progress to NASH.     

Use of Non-Invasive Parameters of Non-Alcoholic Steatohepatitis and Liver Fibrosis in Daily Practice - An Exploratory Case-Control Study

Background

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of a metabolic syndrome. To date, liver biopsy has been the gold standard used to differentiate between simple steatosis and steatohepatitis/fibrosis. Our aim was to compare the relevance of serum non-invasive parameters and scoring systems in the staging of liver fibrosis and non-alcoholic steatohepatitis (NASH) in patients with NAFLD.

Methods and Findings

A total of 112 consecutive patients diagnosed with NAFLD were included. A liver biopsy was performed on 56 patients. The Kleiner score was used for the staging and grading of the histology. Non-invasive parameters for fibrosis (hyaluronic acid; AST/ALT; fibrosis scoring indexes OELF, ELF, BARD score, APRI, NAFLD fibrosis score); and inflammation (M30 and M65 cytokeratin-18 fragments) were measured and calculated. The same analyses were performed in 56 patients diagnosed with NAFLD, who were not indicated for liver biopsy. Based on the liver histology, NASH was diagnosed in 38 patients; simple steatosis in 18 patients. A cut-off value of 750 U/L of serum M65 discriminated patients with and without NASH with a 80% sensitivity and 82% specificity (95% CI:57–95). Fibrosis stage F0–F2 was present in 39 patients; F3–F4 in 17 patients. Serum concentrations of hyaluronic acid were higher in patients with advanced fibrosis (p<0.01); a cut-off value of 25 µg/l discriminated patients with F3–F4 with a 90% sensitivity and 84% specificity from those with F0–F2 (95% CI:59–99). When applying the non-invasive criteria to those patients without a liver biopsy, NASH could only be diagnosed in 16%; however, advanced fibrosis could be diagnosed in 35% of them.

Conclusions

In patients with NAFLD, non-invasive serum parameters with a high accuracy can differentiate those patients with NASH and/or advanced fibrosis from those with simple steatosis. A substantial portion of those patients not indicated for liver biopsy might have undiagnosed advanced fibrosis.     

Lipidomics in pathogenesis,progression and treatment of nonalcoholic steatohepatitis (NASH): Recent advances

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting up to 30% of the general adult population. NAFLD encompasses a histological spectrum ranging from pure steatosis to non-alcoholic steatohepatitis (NASH). NASH can progress to cirrhosis and is becoming the most common indication for liver transplantation, as a result of increasing disease prevalence and of the absence of approved treatments. Lipidomic readouts of liver blood and urine samples from experimental models and from NASH patients disclosed an abnormal lipid composition and metabolism. Collectively, these changes impair organelle function and promote cell damage, necro-inflammation and fibrosis, a condition termed lipotoxicity. We will discuss the lipid species and metabolic pathways leading to NASH development and progression to cirrhosis, as well as and those species that can contribute to inflammation resolution and fibrosis regression. We will also focus on emerging lipid-based therapeutic opportunities, including specialized proresolving lipid molecules and macrovesicles contributing to cell-to-cell communication and NASH pathophysiology.     

Pharmacological Inhibition of the Chemokine CXCL16 Diminishes Liver Macrophage Infiltration and Steatohepatitis in Chronic Hepatic Injury

Non-alcoholic fatty liver disease (NAFLD) is a major cause of morbidity and mortality in developed countries, resulting in steatohepatitis (NASH), fibrosis and eventually cirrhosis. Modulating inflammatory mediators such as chemokines may represent a novel therapeutic strategy for NAFLD. We recently demonstrated that the chemokine receptor CXCR6 promotes hepatic NKT cell accumulation, thereby controlling inflammation in experimental NAFLD. In this study, we first investigated human biopsies (n = 20), confirming that accumulation of inflammatory cells such as macrophages is a hallmark of progressive NAFLD. Moreover, CXCR6 gene expression correlated with the inflammatory activity (ALT levels) in human NAFLD. We then tested the hypothesis that pharmacological inhibition of CXCL16 might hold therapeutic potential in NAFLD, using mouse models of acute carbon tetrachloride (CCl₄)- and chronic methionine-choline-deficient (MCD) diet-induced hepatic injury. Neutralizing CXCL16 by i.p. injection of anti-CXCL16 antibody inhibited the early intrahepatic NKT cell accumulation upon acute toxic injury in vivo. Weekly therapeutic anti-CXCL16 administrations during the last 3 weeks of 6 weeks MCD diet significantly decreased the infiltration of inflammatory macrophages into the liver and intrahepatic levels of inflammatory cytokines like TNF or MCP-1. Importantly, anti-CXCL16 treatment significantly reduced fatty liver degeneration upon MCD diet, as assessed by hepatic triglyceride levels, histological steatosis scoring and quantification of lipid droplets. Moreover, injured hepatocytes up-regulated CXCL16 expression, indicating that scavenging functions of CXCL16 might be additionally involved in the pathogenesis of NAFLD. Targeting CXCL16 might therefore represent a promising novel therapeutic approach for liver inflammation and steatohepatitis.     

非酒精性脂肪肝与脂肪性肝炎动物模型研究进展

非酒精性脂肪肝是无酒精滥用的包括单纯性脂肪肝、脂肪性肝炎、脂肪性肝纤维化和肝硬化的肝病综合征,目前已成为广受关注的肝病医学难题。随着抗脂肪肝药物的深入研究,动物模型制作得到很好发展。近年来,在大鼠、沙鼠、小鼠、兔和小猪等动物种属成功地建立了食物、胃肠外营养与蛋氨酸胆碱缺乏等诱导的单纯性脂肪肝和脂肪性肝炎动物模型,这些模型为研究脂肪肝和脂肪性肝炎的发病机理与治疗提供了机会。每种动物模型各有优缺点,合理应用动物模型能更好地开展脂肪肝病的实验和临床研究。本文综述了非酒精性脂肪肝及脂肪性肝炎动物模型制作方法的若干研究进展。