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。     

非酒精性脂肪性肝病的发病机制及治疗进展

近年来,随着人们生活水平的提高,脂肪性肝病的发病率明显上升,且患病年龄趋于低龄化,已经成为严重危害我国人民健康的常见疾病,我国非酒精性脂肪性肝病的发病率明显高于酒精性脂肪性肝病。本文主要对NAFLD的发病机制及相关治疗进展做简要的综述。NAFLD的发病机制与胰岛素抵抗、氧化应激、代谢综合征、脂肪细胞因子的作用、内质网应激、及铁超载等多种因素有关。NAFLD的治疗可以从防治原发病或相关危险因素、基础治疗(行为或生活方式干预;调整饮食;运动疗法)、药物治疗以及手术治疗等方面进行。了解国际上NAFLD的发病机制以及相关治疗进展,对遏制非酒精性脂肪性肝病的发生、发展趋势有着十分重要的意义。     

非酒精性脂肪性肝病诊断方法研究进展

非酒精性脂肪性肝病(non-alcoholic fatty liver disease, NAFLD)是一类进行性的慢性肝脏疾病,包括简单的脂肪蓄积、非酒精性脂肪性肝炎、进展性的肝纤维化、肝硬化和肝细胞肝癌。NAFLD具有致病机制复杂、疾病进行性、高发病率、伴随并发症风险以及无特效药物治疗等特征,这凸显出对NAFLD的发病机制认知、筛查、诊断与监测的重要性。因此,该文旨在介绍NAFLD的概况,着重从肝穿刺组织活检、影像学检查和血液标志物三个方面归纳与总结诊断方法的研究进展,为NAFLD的基础研究、临床诊断及其新的生物标志物研究提供相关的参考。     

非酒精性脂肪性肝病与肠粘膜屏障关系的研究进展

近年来,非酒精性脂肪性肝病的发病率正呈逐年升高趋势,且可进一步发展为非酒精性肝炎、肝硬化甚至肝癌,但其具体的发病机制目前尚未完全阐明。迄今为止,关于非酒精性脂肪性肝病较为人们所接受的是"两次打击学说",即肝脏的脂肪变性及脂质的过氧化反应。自"肠-肝轴"被提出后,关于肠道粘膜屏障功能与非酒精性脂肪性肝病的发生和发展的关系备受研究人员的关注。近些年来,关于非酒精性脂肪性肝病与肠道粘膜的机械屏障、生物屏障、化学屏障、免疫屏障方面的研究越来越多,肠粘膜的四个屏障功能与非酒精性脂肪性肝病密切相关,相互影响共同促进疾病的发生发展。本文就非酒精性脂肪性肝病与肠粘膜屏障关系的研究进展进行了综述。     

肝细胞程序性坏死与非酒精性脂肪性肝病

非酒精性脂肪性肝病是目前世界上最常见的慢性肝病,其发病机制尚不清楚。肝细胞死亡与该病的相关性已被广泛报道。程序性坏死是一种细胞死亡形式。研究发现,肝细胞程序性坏死在非酒精性脂肪性肝病的发展过程中发挥重要作用。本文就近年来肝细胞程序性坏死在非酒精性脂肪性肝病中的研究进展作一综述,旨在为非酒精性脂肪性肝病的发病机制与药物治疗提供新思路。     

GSDMD调控非酒精性脂肪肝中细胞焦亡的研究进展

细胞焦亡是一种炎症相关的细胞程序性死亡方式,由胱天蛋白酶(caspase)和炎性小体介导,最终依赖gasdermin家族成员gasdermin D(GSDMD)执行。细胞焦亡的发生伴随着细胞内炎性因子的外泄及免疫细胞的活化,因此与炎症反应的发生密切相关。非酒精性脂肪性肝病(nonalcoholic fatty liver disease, NAFLD)是一种病因不明的慢性肝病,如果缺乏有效的干预手段,脂肪变性会逐渐进展至炎症、纤维化,最终发展至肝硬化。GSDMD 介导的细胞焦亡在非酒精性脂肪性肝病的发病过程中扮演重要角色,不仅会导致肝细胞死亡,还会加重炎症反应和纤维化的进程。抑制GSDMD 的功能从而减少细胞焦亡能够有效地缓解NAFLD 中的脂质堆积和炎症反应,这将为NAFLD 的治疗开辟一个新的研究方向。本文将概述GSDMD 介导的细胞焦亡的分子机制,并关注GSDMD 和细胞焦亡在NAFLD 发病机制及治疗方面的研究进展,为NAFLD 的诊治提供新思路。     

NAFLD患者肠粘膜机械屏障损伤的研究

非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)是慢性肝损伤的主要病因之一。据估计,大约有20%的成人有非酒精性脂肪性肝病,2%-3%发展成非酒精性脂肪性肝炎(nonalcoholic steatohepatitis,NASH)。NASH是NAFLD的渐进形式,并可能导致肝硬化和肝细胞癌。NAFLD不仅增加了肝病患者死亡率,作为代谢综合征,还增加了肥胖、2型糖尿病及高脂血症的发病率。肌球蛋白轻链激酶(MLCK)是细胞收缩的关键酶,可使肌球蛋白轻链磷酸化(MLC),促使肌动蛋白收缩,破坏细胞间的紧密连接蛋白,使细胞骨架收缩,进而使肠上皮通透性增加,肠粘膜机械屏障遭到破坏,致使NAFLD的病情进一步发展。MLCK在NAFLD的发生及发展中起着重要作用。NAFLD严重威胁人类健康,影响人们的生活质量及生存质量。为NAFLD患者寻找崭新的治疗方法是极其必要的。     

非酒精性脂肪性肝病的药物治疗进展

非酒精性脂肪性肝病已日渐成为目前慢性肝病的主要病因,其与肥胖、2型糖尿病和代谢综合征等疾病密切相关,疾病谱主要包括非酒精性单纯性脂肪肝、非酒精性脂肪性肝炎和肝硬化。早期诊断和及时治疗可望减轻NAFLD患者肝炎的严重程度并延缓肝纤维化的进展,减少并发症的出现。目前认为其发病与胰岛素抵抗、氧化应激及脂质过氧化和肠道菌群失调等因素有关。通过饮食调整和适当运动而减轻体重被认为是最基础的治疗措施,但单纯依靠减肥治疗脂肪性肝病(FLD)的效果并不理想,药物在脂肪性肝炎防治中的作用同样不可忽视。目前没有根治这一疾病的特效药物,单纯针对某一发病机制的药物亦难以治愈NAFLD这种复杂的疾病,本文主要从改善胰岛素抵抗、降脂、保肝抗炎及改善肠道菌群等四方面介绍一下本病的药物治疗进展。提倡改变生活方式的非药物治疗与药物干预治疗紧密结合,以取得最理想的治疗效果。     

PPARs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(non-alcoholic fatty liver disease,NAFLD)是西方国家最常见的慢性肝脏疾病,其疾病谱包括肝脂肪变性,脂肪性肝炎,进一步的肝纤维化、肝硬化,甚至肝细胞性肝癌。其发病机制尚未明确,通常解释为"二次打击"学说。然而新的研究发现非甘油三酯在肝脏的沉积,而是脂肪酸(fatty acids,FAs)及其代谢产物等可能对肝脏有毒性作用。过氧化物酶体增殖物激活受体(PPARs)是配体激活的转录因子,是核受体超家族成员之一,具有调节脂质及糖代谢、抗炎和抗纤维化作用,尤其在FAs储存及分解代谢中起到核心作用,与NAFLD的发生发展密切相关,可能作为治疗NAFLD有效靶点。本文将对PPARs在NAFLD发病机制中的作用做一综述。     

细胞外囊泡在非酒精脂肪肝发病机制及诊断治疗中的作用

非酒精性脂肪性肝病(nonalcoholic fatty liver disease, NAFLD)是21世纪全球最重要的公共健康问题之一,也是我国愈来愈重要的慢性肝病问题。细胞间通讯在NAFLD病理进程中发挥重要作用。细胞外囊泡(extracellular vesicles, EVs)是近年来备受关注的细胞间通讯方式。EVs携带脂质、蛋白质、DNA、mRNA以及非编码RNA等作为信号分子在细胞间的物质和信息交流中起重要作用,参与了多个生理病理过程。目前细胞外囊泡在非酒精脂肪肝发病机制及诊断治疗中的作用方面的研究非常有限,但初步研究显示, EVs在NAFLD病程发展中发挥重要作用。因此,该文重点关注EVs参与NAFLD病程机制研究,并对其在NAFLD防治中的潜在诊疗价值作简要综述。     

Fatty liver: Role of inflammation and fatty acid nutrition

Nonalcoholic fatty liver disease (NAFLD) refers to a wide spectrum of liver damage, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. NAFLD is strongly associated with insulin resistance and is defined by accumulation of liver fat >5% per liver weight in the presence of <10 g of daily alcohol consumption. The exact prevalence of NAFLD is uncertain because of the absence of simple noninvasive diagnostic tests to facilitate an estimate of prevalence but in subgroups of people such as those with type 2 diabetes, the prevalence may be as high as 70%. NASH is an important subgroup within the spectrum of NAFLD that progresses over time with worsening fibrosis and cirrhosis, and NASH is associated with increased risk for cardiovascular disease. It is, therefore, important to understand the pathogenesis of NASH specifically, to develop strategies for interventions to treat this condition. The purpose of this review is to discuss the roles of inflammation, fatty acids and fatty acids in nutrition, in the pathogenesis and potential treatment of NAFLD.     

Lipid metabolism and liver inflammation. II. Fatty liver disease and fatty acid oxidation

Fatty liver disease (FLD), whether it is alcoholic FLD (AFLD) or nonalcoholic FLD (NAFLD), encompasses a morphological spectrum consisting of hepatic steatosis (fatty liver) and steatohepatitis. FLD has the inherent propensity to progress toward the development of cirrhosis and hepatocellular carcinoma. It is generally difficult to distinguish AFLD from NAFLD on morphological grounds alone despite the distinctions implied by these etiological designations. The indistinguishable spectrum of histological features of both AFLD and NAFLD suggests a possible convergence of pathogenetic mechanisms at some critical juncture that enables the progression of steatohepatitis toward cirrhosis and liver cancer. From a pathogenetic perspective, FLD may be considered a single disease with multiple etiologies. Excess energy consumption and reduced energy combustion appear to be critical events that culminate in lipid storage in the liver. Energy combustion in the liver is controlled by peroxisome proliferator-activated receptor (PPAR)-alpha-regulated mitochondrial and peroxisomal fatty acid beta-oxidation systems and the microsomal omega-oxidation system. PPAR-alpha, a receptor for peroxisome proliferators, functions as a sensor for fatty acids (lipid sensor), and ineffective PPAR-alpha sensing can lead to reduced energy burning resulting in hepatic steatosis and steatohepatitis. Delineation of the pathogenetic aspects of FLD is necessary for developing novel therapeutic strategies for this disease.     

Pro-inflammatory signalling and gut-liver axis in non-alcoholic and alcoholic steatohepatitis: Differences and similarities along the path

Non-alcoholic fatty liver disease (NAFLD) and alcohol-associated liver disease (ALD) represent a spectrum of injury, ranging from simple steatosis to steatohepatitis and cirrhosis. In humans, in fact, fatty changes in the liver, possibly leading to end-stage disease, were observed after chronic alcohol intake or in conditions of metabolic impairment. In this article, we examined the features and the pro-inflammatory pathways leading to non-alcoholic and alcoholic steatohepatitis. The involvement of several events (hits) and multiple inter-related pathways in the pathogenesis of these diseases suggest that a single therapeutic agent is unlikely to be an effective treatment strategy. Hence, a combination treatment towards multiple pro-inflammatory targets would eventually be required. Gut-liver crosstalk is involved not only in the impairment of lipid and glucose homoeostasis leading to steatogenesis, but also in the initiation of inflammation and fibrogenesis in both NAFLD and ALD. Modulation of the gut-liver axis has been suggested as a possible therapeutic approach since gut-derived components are likely to be involved in both the onset and the progression of liver damage. This review summarizes the translational mechanisms underlying pro-inflammatory signalling and gut-liver axis in non-alcoholic and alcoholic steatohepatitis. With a multitude of people being affected by liver diseases, identification of possible treatments and the elucidation of pathogenic mechanisms are elements of paramount importance.     

MicroRNAs in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), or, more accurately, metabolic associated fatty liver disease, accounts for a large proportion of chronic liver disorders worldwide and is closely associated with other conditions such as cardiovascular disease, obesity, and type 2 diabetes mellitus. NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH) and can progress to cirrhosis and, eventually, also hepatocellular carcinoma. The morbidity and mortality associated with NAFLD are increasing rapidly year on year. Consequently, there is an urgent need to understand the etiology and pathogenesis of NAFLD and identify effective therapeutic targets. MicroRNAs (miRNAs), important epigenetic factors, have recently been proposed to participate in NAFLD pathogenesis. Here, we review the roles of miRNAs in lipid metabolism, inflammation, apoptosis, fibrosis, hepatic stellate cell activation, insulin resistance, and oxidative stress, key factors that contribute to the occurrence and progression of NAFLD. Additionally, we summarize the role of miRNA-enriched extracellular vesicles in NAFLD. These miRNAs may comprise suitable therapeutic targets for the treatment of this condition.     

Six-Transmembrane Epithelial Antigen of Prostate 3 Promotes Hepatic Insulin Resistance and Steatosis

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by excessive deposition of fatty acids in the liver. Further deterioration leads to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma, creating a heavy burden on human health and the social economy. Currently, there are no effective and specific drugs for the treatment of NAFLD. Therefore, it is important to further investigate the pathogenesis of NAFLD and explore effective therapeutic targets for the prevention and treatment of the disease. Six-transmembrane epithelial antigen of prostate 3 (STEAP3), a STEAP family protein, is a metalloreductase. Studies have shown that it can participate in the regulation of liver ischemia-reperfusion injury, hepatocellular carcinoma, myocardial hypertrophy, and other diseases. In this study, we found that the expression of STEAP3 is upregulated in NAFLD. Deletion of STEAP3 inhibits the development of NAFLD in vivo and in vitro, whereas its overexpression promotes palmitic acid/oleic acid stimulation-induced lipid deposition in hepatocytes. Mechanistically, it interacts with transforming growth factor beta-activated kinase 1 (TAK1) to regulate the progression of NAFLD by promoting TAK1 phosphorylation and activating the TAK1-c-Jun N-terminal kinase/p38 signaling pathway. Taken together, our results provide further insight into the involvement of STEAP3 in liver pathology.     

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。     

The hedgehog pathway in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of obesity-associated liver diseases and it has become the major cause of cirrhosis in the Western world. The high prevalence of NAFLD-associated advanced liver disease reflects both the high prevalence of obesity-related fatty liver (hepatic steatosis) and the lack of specific treatments to prevent hepatic steatosis from progressing to more serious forms of liver damage, including nonalcoholic steatohepatitis (NASH), cirrhosis, and primary liver cancer. The pathogenesis of NAFLD is complex, and not fully understood. However, compelling evidence demonstrates that dysregulation of the hedgehog (Hh) pathway is involved in both the pathogenesis of hepatic steatosis and the progression from hepatic steatosis to more serious forms of liver damage. Inhibiting hedgehog signaling enhances hepatic steatosis, a condition which seldom results in liver-related morbidity or mortality. In contrast, excessive Hh pathway activation promotes development of NASH, cirrhosis, and primary liver cancer, the major causes of liver-related deaths. Thus, suppressing excessive Hh pathway activity is a potential approach to prevent progressive liver damage in NAFLD. Various pharmacologic agents that inhibit Hh signaling are available and approved for cancer therapeutics; more are being developed to optimize the benefits and minimize the risks of inhibiting this pathway. In this review we will describe the Hh pathway, summarize the evidence for its role in NAFLD evolution, and discuss the potential role for Hh pathway inhibitors as therapies to prevent NASH, cirrhosis and liver cancer.