Steatosis in chronic hepatitis C: association with increased messenger RNA expression of collagen I,tumor necrosis factor-alpha and cytochrome P450 2E1

BACKGROUND: Increased levels of tumor necrosis factor (TNF)-alpha and oxidative stress have been implicated as factors contributing to hepatic injury in fatty liver diseases. As steatosis is associated with an accelerated progression of fibrosis in chronic hepatitis C (HCV), we hypothesized that the messenger (m)RNA expression of genes involved with the production of reactive oxygen species, inflammation and cellular injury would be increased in liver tissue from subjects with steatosis and chronic HCV. METHODS: Real-time polymerase chain reaction was performed to determine relative mRNA expression levels of collagen I, TNF-alpha, cytochrome P450 2E1 (CYP 2E1), transforming growth factor-beta1 and CD14 in liver biopsies from 38 patients with chronic HCV. The mRNA expression levels were compared between subjects with and without steatosis, fibrosis, and inflammation. RESULTS: Multivariate analysis demonstrated that collagen I mRNA expression was increased by 199% in steatosis (P = 0.02), 85% in moderate to severe fibrosis (P = 0.02) and 157% in inflammation (P = 0.03). Livers of patients with steatosis also had an increase in TNF-alpha mRNA expression by 50% (P = 0.03) and CYP 2E1 expression by 37% (P = 0.04) compared with non-steatotic livers. Tumor necrosis factor-alpha protein was localized to Kupffer cells, bile ducts and portal inflammatory cells by immunohistochemistry. CONCLUSION: Increased expression of TNF-alpha may be involved in the pathogenesis of liver injury and progression of fibrosis in individuals who have steatosis in association with chronic HCV.     

Role of Kupffer cells in host defense and liver disease.

Kupffer cells (KC) constitute 80-90% of the tissue macrophages present in the body. They reside within the lumen of the liver sinusoids, and are therefore constantly exposed to gut-derived bacteria, microbial debris and bacterial endotoxins, known to activate macrophages. Upon activation KC release various products, including cytokines, prostanoides, nitric oxide and reactive oxygen species. These factors regulate the phenotype of KC themselves, and the phenotypes of neighboring cells, such as hepatocytes, stellate cells, endothelial cells and other immune cells that traffic through the liver. Therefore, KC are intimately involved in the liver's response to infection, toxins, ischemia, resection and other stresses. This review summarizes established basic concepts of KC function as well as their role in the pathogenesis of various liver diseases.     

Pleiotropy within gene variants associated with nonalcoholic fatty liver disease and traits of the hematopoietic system

Genome-wide association studies of complex diseases, including nonalcoholic fatty liver disease (NAFLD), have demonstrated that a large number of variants are implicated in the susceptibility of multiple traits — a phenomenon known as pleiotropy that is increasingly being explored through phenome-wide association studies. We focused on the analysis of pleiotropy within variants associated with hematologic traits and NAFLD. We used information retrieved from large public National Health and Nutrition Examination Surveys, Genome-wide association studies, and phenome-wide association studies based on the general population and explored whether variants associated with NAFLD also present associations with blood cell-related traits. Next, we applied systems biology approaches to assess the potential biological connection/s between genes that predispose affected individuals to NAFLD and nonalcoholic steatohepatitis, and genes that modulate hematological-related traits—specifically platelet count. We reasoned that this analysis would allow the identification of potential molecular mediators that link NAFLD with platelets. Genes associated with platelet count are most highly expressed in the liver, followed by the pancreas, heart, and muscle. Conversely, genes associated with NAFLD presented high expression levels in the brain, lung, spleen, and colon. Functional mapping, gene prioritization, and functional analysis of the most significant loci (P < 1 × 10^-8) revealed that loci involved in the genetic modulation of platelet count presented significant enrichment in metabolic and energy balance pathways. In conclusion, variants in genes influencing NAFLD exhibit pleiotropic associations with hematologic traits, particularly platelet count. Likewise, significant enrichment of related genes with variants influencing platelet traits was noted in metabolic-related pathways. Hence, this approach yields novel mechanistic insights into NAFLD pathogenesis.     

环氧合酶-2与肝脏疾病的研究进展

环氧合酶-2是人体合成前列腺素的关键酶,参与炎症反应、细胞增殖与凋亡,在多种疾病中发挥作用.近年来研究发现,环氧合酶-2与肝脏疾病发生发展密切相关,选择性环氧合酶-2抑制剂有望成为临床治疗肝病的有效药物.本文就环氧合酶-2与肝脏疾病的研究进展作一综述.     

Pediatric liver diseases: current challenges and future perspectives

Chronic liver diseases in children represent a rising problem with significant effects on public health. In fact, several pediatric liver diseases are precursors of adult chronic hepatopathies, cirrhosis and hepatocellular carcinoma. The prevalence of liver diseases in children is unknown. In the USA, every year, 15,000 children are hospitalized for liver diseases, but these disorders continue to be under-recognized or diagnosed late. The main reason is due to the frequent absence of symptoms in the vast majority of liver diseases, especially in the early stages. In the last few decades several advances have been made in understanding the pathogenesis of liver diseases, permitting the discovery of new therapeutic targets to treat liver diseases, thus improving the natural history of these disorders. In this article we discuss the most recent advances in the understanding of the pathogenesis, diagnosis and treatment of the most frequent pediatric liver diseases.     

Glutathione-S-transferase gene polymorphisms (GSTT1, GSTM1, GSTP1) as increased risk factors for asthma

OBJECTIVES: Asthma is a complex multifactorial disease with an obvious genetic predisposition, immunological aberration, and involvement of noxious environmental factors. Polymorphisms of the glutathione-S-transferase (GST) genes are known risk factors for some environmentally-related diseases. In the present study, the hypothesis that polymorphisms in the GSTT1, GSTM1 and GSTP1 genes are associated with atopic and nonatopic asthma was examined. METHODOLOGY: The study population consisted of 103 unrelated healthy individuals and 101 patients with bronchial asthma (64 atopic, 37 nonatopic). Asthma was diagnosed according to the American Thoracic Society statement. Genotyping of polymorphisms in the GSTT1, GSTM1 and GSTP1 genes was performed using real time polymerase chain reaction with a Light Cycler instrument and hybridization probes in combination with the Light Cycler DNA master hybridization probes kit. RESULTS: Patients with atopic asthma (34.4%) had a higher prevalence of the GSTT1 null genotype than the nonatopic asthma patients (13.5%; OR = 3.83; 95% CI, 1.24-11.78). Asthma patients (63.4%) had a higher prevalence of the GSTM1 null genotype than the control group (40.8%; OR = 2.34; 95% CI, 1.31-4.20). Subjects with the GSTP1 homozygous Val/Val genotype had a 3.55-fold increased risk of having atopic asthma compared to nonatopic asthma (OR = 3.55; 95% CI, 1.10-12.56). CONCLUSIONS: These results suggest that the GSTT1 and GSTM1 null genotypes and the GSTP1 Val/Val polymorphism may play important roles in asthma pathogenesis. It is possible that intermediate electrophilic metabolites, arising in the first phase of detoxification, are not metabolized by GST enzymes in asthmatic patients and are not excreted. These intermediate metabolites may damage cells and generate oxidative stress, and so contribute to the pathogenesis of asthma.     

慢性乙型肝炎和肝病中Fas和FasL表达的原位研究

目的了解慢性乙型肝炎和肝病时介导凋亡的Ｆａｓ／ＦａｓＬ表现。方法以免疫组化法原位检查各种慢性肝病４５例的活检肝组织。结果肝内浸润的淋巴细胞中检出ＦａｓＬ，肝细胞Ｆａｓ／ＦａｓＬ表达与炎症活动性一致，多分布在界面性炎症区。肝细胞表达ＦａｓＬ，可能也发挥细胞毒效应。结论新的发现是ＦａｓＬ可在肝细胞结节和肝癌细胞表达，提示有细胞毒效应的ＦａｓＬ在ＨＢ相关慢性肝病中有发病学意义。肝癌细胞中未检出Ｆａｓ而检出ＦａｓＬ，可能是一种肿瘤逃避免疫攻击的机制     

Human leukocyte antigen DQ2/8 prevalence in non-celiac patients with gastrointestinal diseases

AIM: To investigate the prevalence of human leukocyte antigen (HLA) DQ2/8 alleles in Southern Italians with liver and gastrointestinal (GI) diseases outside of celiac disease. METHODS: HLA DQ2/8 status was assessed in 443 patients from three ambulatory gastroenterology clinics in Southern Italy (University of Federico Ⅱ, Naples, Loreto Crispi Hospital, Ruggi D’Aragona Hospital, Salerno). Patients were grouped based on disease status [pre-post transplant liver disease, esophageal/gastric organic and functional diseases, irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD)] and DQ2/8 alleles, which correspond to a celiac disease genetic risk gradient. Subject allele frequencies were compared to healthy Italian controls. RESULTS: One hundred and ninety-six out of four hundred and forty-three (44.2%) subjects, median age 56 years and 42.6% female, were DQ2/8 positive. When stratifying by disease we found that 86/188 (45.7%) patients with liver disease were HLA DQ2/8 positive, 39/73 (53.4%) with functional upper GI diseases and 19/41 (46.3%) with organic upper GI diseases were positive. Furthermore, 38/105 (36.2%) patients with IBS and 14/36 (38.9%) with IBD were HLA DQ2/8 positive (P = 0.21). Compared to healthy controls those with functional upper GI diseases disorders had a 1.8 times higher odds of DQ2/8 positivity. Those with liver disease had 1.3 times the odds, albeit not statistically significant, ofDQ2/8 positivity. Both those with IBS and IBD had a lower odds of DQ2/8 positivity compared to healthy controls. CONCLUSION: The proportion of individuals HLA DQ2/8 positive is higher in those with liver/upper functional GI disease and lower in IBS/IBD as compared to general population estimates.     

Role of the diet as a link between oxidative stress and liver diseases

Oxidative stress is caused by an imbalance between the production of reactive oxygen(free radicals) and the body’s ability(antioxidant capacity) to readily detoxify the reactive intermediates or easily repair the resulting damage. An adequate diet, characterized by daily intake of foods associated with improvementsin the total antioxidant capacity of individuals and reduced incidence of diseases related to oxidation, can modulate the degree of oxidative stress. In fact, dietderived micronutrients may be direct antioxidants, or are components of antioxidant enzymes, leading to improvement of some indicators of hepatic function. However, although their increased dietary intake might be beneficial, literature data are still controversial. This review summarizes what is known about the effects of diet nutrients on oxidative stress, inflammation and liver function. Moreover, we have analyzed:(1) the main nutritional components involved in the production and/or removal of free radicals; and(2) the role of free radicals in the pathogenesis of several hepatic diseases and related comorbidities.     

Increased lipid peroxidation in patients with non-alcoholic fatty liver disease and chronic hepatitis C as measured by the plasma level of 8-isoprostane

BACKGROUND: Oxidative stress plays an important role in the pathogenesis of chronic liver diseases. The plasma level of 8-isoprostane, a product of lipid peroxidation, is a marker of oxidative stress in vivo. The aim of the present study was to clarify whether the degree of lipid peroxidation, as measured by the plasma level of 8-isoprostane, influences the progression of chronic liver diseases and hepatocarcinogenesis. METHODS: Plasma 8-isoprostane levels were investigated in 14 patients with non-alcoholic fatty liver disease (NAFLD), 75 with chronic hepatitis C (CH-C), 14 with cured CH-C, 14 with HCV-positive hepatocellular carcinoma (HCC-C) and 38 healthy volunteers. 8-Isoprostane was measured by enzyme immunoassay after affinity column purification. RESULTS: Plasma 8-isoprostane was significantly elevated in NAFLD (11.9 [3.8-56.8] pg/mL), CH-C (10.1 [4.2-134.5] pg/mL) as compared to controls (6.3 [3.6-11.1] pg/mL). Plasma 8-isoprostane values were positively correlated with body mass index in NAFLD (P < 0.05) and with total cholesterol in cured CH-C (P < 0.01). 8-Isoprostane levels were not significantly related to sex, age, biochemical data or iron metabolism markers in all liver diseases. In addition, after the administration of peg-interferon, the values of 8-isoprostane improved in almost all patients, reaching values of healthy subjects. CONCLUSIONS: 8-Isoprostane values are elevated in patients with NAFLD and CH-C as compared to healthy controls. Oxidative stress caused by increased lipid peroxidation is involved in the pathogenesis of NAFLD and CH-C.     

Recent advances in dietary supplementation,in treating non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD) is currently known as the most common liver problem, characterized by excessive lipid accumulation in hepatocytes,which may progress to other liver diseases such as nonalcoholic steatohepatitis, hepatic tissue fibrosis, livercirrhosis, and failure or hepatocellular carcinoma. Since NAFLD is positively associated with the development of obesity, insulin resistance, and ultimately type 2 diabetes mellitus, it is often regarded as the hepatic manifestation of the metabolic syndrome. No pharmacologic treatment has yet been proven for this disease. For most patients with presumed or confirmed NAFLD, the only proven strategy is to offer lifestyle advice that can lead to sustained weight loss. Since insulin resistance, oxidative stress, inflammation, and necro-apoptosis are involved in NAFLD pathogenesis, it seems that every potential therapeutic agent should target one or some of these pathologic events. There are many well known anti-oxidants, anti-inflammatory, and insulin sensitizer dietary supplements which have shown beneficial effects on NAFLD improvement in animal and human studies. The purpose of this review is to explore the existing evidences on dietary supplements considered to have hepatoprotective properties, and to present some proposed mechanisms by which they may protect against NAFLD.     

Liver and Bone

Abstract  To investigate the pathogenesis of hepatic osteodystrophy (HOD) in parenchymal liver disease, we developed a laboratory model in animals using carbon tetrachloride (CCl₄) and thioacetamide. Biochemical and histological parameters in the model were measured. In rats with both chronic non-cirrhotic liver injury and CCl₄-induced cirrhosis, tibial bone volume was significantly lower than in controls. In CCl₄-treated cirrhotic rats, the osteoid volume decreased while the urinary calcium/creatinine ratio increased. In all CCl₄-treated rats, bone volume was significantly correlated with both the serum albumin concentration and the number of goblet cells reflecting intestinal villous atrophy. The serum concentration of vitamin D metabolites was not correlated with bone volume. Whole body retention of ⁴⁷Ca was significantly lower in CCl₄-treated cirrhotic rats than in controls. Furthermore, the bone volume in thioacetamide-treated cirrhotic rats was significantly lower than in controls. These data demonstrate that chronic parenchymal liver injury itself causes osteoporosis (i.e. HOD) due to a combination of low bone formation rates and high resorption rates, that HOD begins at the stage of chronic non-cirrhotic liver injury, that bone volume in HOD parallels liver damage and that the principal pathogenesis of HOD seems to be intestinal Ca malabsorption due to lower serum albumin and villous atrophy, while serum levels of vitamin D metabolites have little influence on the pathogenesis of HOD.     

Vitamin D deficiency in chronic liver disease

Vitamin D is an important secosteroid hormone with known effect on calcium homeostasis, but recently there is increasing recognition that vitamin D also is involved in cell proliferation and differentiation, has immunomodulatory and anti-inflammatory properties. Vitamin D deficiency has been frequently reported in many causes of chronic liver disease and has been associated with the development and evolution of non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC) virus infection. The role of vitamin D in the pathogenesis of NAFLD and CHC is not completely known, but it seems that the involvement of vitamin D in the activation and regulation of both innate and adaptive immune systems and its antiproliferative effect may explain its importance in these liver diseases. Published studies provide evidence for routine screening for hypovitaminosis D in patients with liver disease. Further prospectives studies demonstrating the impact of vitamin D replacement in NAFLD and CHC are required.     

PNPLA3基因在非酒精性脂肪性肝病中的作用

非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD) 在世界范围内发病率成日益上升趋势,其相关基因研究对完善其致病机制,补充其治疗方案及改善预后至关重要.目前,国内外多项实验证实含patatin 样磷脂酶域3(PNPLA3) 基因突变与NAFLD 密切相关,考虑其与肝脏脂...     

Gene expression profiling of non‐alcoholic steatohepatitis using gene set enrichment analysis

Aim: Non‐alcoholic steatohepatitis (NASH) is a subset of non‐alcoholic fatty liver disease (NAFLD) and sometimes progresses to cirrhosis and liver failure. In this study we analyzed the expression profile of genes and biological pathways involved in NASH in comparison with non‐NASH by gene set enrichment analysis (GSEA) employing a DNA microarray technique. Methods: mRNA from liver biopsy specimens was collected from a group of NASH patients and a group of non‐NASH patients. We analyzed the relative abundance of mRNA using high‐density oligonucleotide microarrays containing probes for 54 675 known genes, and investigated the pathogenetic mechanisms of NASH by means of a powerful technique for analyzing molecular profiling data, GSEA. Results: The results showed that the level of expression of 27 gene sets was significantly higher and the level of expression of 25 gene sets was significantly lower in the NASH samples than in the non‐NASH samples. Based on these results we created an online, publicly available, searchable database containing the data for the gene expression profiles of the NASH patients ( http://www2.genome.rcast.u‐tokyo.ac.jp/___/NASH/NASH_GSEA2/ ). Conclusion: Our data revealed differences in expression of many gene sets that are involved in the pathogenesis of NASH.     

Cellular endo‐lysosomal dysfunction in the pathogenesis of non‐alcoholic fatty liver disease

Non‐alcoholic fatty liver disease (NAFLD), an increasingly devastating human disorder, is characterized by intrahepatic fat accumulation. Although important progress has been made in understanding NAFLD, the fundamental mechanisms involved in the pathogenesis of NAFLD have not been fully explained. The endo‐lysosomal trafficking network is central to lipid metabolism, protein degradation and signal transduction, which are involved in a variety of diseases. In recent years, many genes and pathways in the endo‐lysosomal trafficking network and involved in lysosomal biogenesis have been associated with the development and progression of NAFLD. Mutations of these genes and impaired signalling lead to dysfunction in multiple steps of the endo‐lysosomal network (endocytic trafficking, membrane fusion and lysosomal degradation), resulting in the accumulation of pathogenic proteins. In this review, we will focus on how alterations in these genes and pathways affect endo‐lysosomal trafficking as well as the pathophysiology of NAFLD.     

Short report: Severe Plasmodium falciparum malaria in Cameroon: associated with the glutathione S-transferase M1 null genotype

Glutathione S-transferases (GST) are a family of enzymes involved in phase-II detoxification of endogenous and xenobiotic compounds. Polymorphisms in GST genes have been associated with susceptibility to different diseases. In this study we determined the frequencies of polymorphisms in GSTM1, GSTT1, and GSTP1 in DNA of 138 children from Cameroon, presenting with uncomplicated malaria (N = 19), malaria with minor complications (N = 81), or severe malaria (N = 38). Analyses of GSTM1 and GSTT1 were performed using PCR-multiplex procedure, while GSTP1 was done by PCR-RFLP. Subjects presenting with malaria with complications were found more often of the GSTM1-null genotype (58-64%) as compared with those with uncomplicated malaria (32%), a difference that was statistically significant. We conclude that the GSTM1-null genotype is associated with malaria with complications.     

NF-κB的结构和功能研究及与酒精性肝病的关系

酒精性肝病 （ alcoholic liver disease, ALD） 是由于长期大量饮酒导致的中毒性肝损害,包括酒精性脂肪肝、酒精性肝炎、酒精性肝硬化。研究发现,核因子κB（NF—κB）作为一种多功能的细胞转录因子,在肝脏炎症、纤维化及肝细胞再生、凋亡等病理生理中起着重要作用。NF—κB通过调控细胞激酶、趋化因子、生长因子、细胞黏附因子及早期反应的蛋白质分子基因的转录而参与炎症和免疫反应、某些疾病的病理产生、急性期反应、细胞增殖和细胞凋亡及对病毒感染的反应等。由于广泛参与许多基因的转录调控及细胞的凋亡调控和转化,故NF—κB在许多疾病中高度表达。