8-hydroxy-2--deoxyguanosine and Non-alcoholic-Fatty-Liver-Disease

The progression of nonalcoholic fatty liver disease (NAFLD) into severe histological forms (steatohepatitis - NASH) is paralleled by the occurrence of complex molecular processes. Mitochondrial dysfunction is a hallmark feature of advanced disease. Mitochondrially encoded cytochrome B (cytochrome b, MT-CYB), a member of the oxidative phosphorylation system, is a key component of the respirasome supercomplex. Here, we hypothesized that NAFLD severity is associated with liver tissue cytochrome b mutations and damaged mitochondrial DNA (mtDNA).. We included 252 liver specimens of NAFLD patients - in whom histological disease ranged from mild to severe - which were linked to clinical and biochemical information. Tissue molecular explorations included MT-CYB sequencing and analysis of differential mtDNA damage. Profiling of circulating Krebs cycle metabolites and global liver transcriptome was performed in a subsample of patients. Tissue levels of 4-hydroxynonenal - a product of lipid peroxidation and 8-hydroxy-2'-deoxyguanosine, a marker of oxidative damage - were measured.. Compared to simple steatosis, NASH is associated with a higher level of MT-CYB variance, 12.1 vs. 15.6 substitutions per 10. NASH is associated with genetic alterations of the liver cellular respirasome, including high cytochrome b variation and mtDNA damage, which may result in broad cellular effects.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aldehydes; Amino Acids, Branched-Chain; Cytochromes b; Disease Progression; DNA Damage; DNA, Mitochondrial; Glutamic Acid; Glutarates; Humans; Lipid Peroxidation; Liver; Middle Aged; Mutation; Non-alcoholic Fatty Liver Disease; Obesity; Oxidative Phosphorylation; Oxidative Stress; Severity of Illness Index; Transcriptome

Studies have shown that liraglutide, or human umbilical cord mesenchymal stem cell (hUC-MSCs) can improve non-alcoholic fatty liver disease (NAFLD). However there have been no studies on the combination of the two used to treat NAFLD. This study aimed to explore the therapeutic effects of combination of liraglutide and hUC-MSCs on liver injury in rats with type 2 diabetes mellitus (T2DM) and NAFLD, and further investigate their mechanisms. Sprague Dawley rats fed by a high fat and high sucrose diet were randomly divided into 5 groups, including NC group, T2DM/NAFLD group, liraglutide group (treated with liraglutide, 200 μg/kg, twice daily for 8 weeks), hUC-MSCs group (treated with hUC-MSCs at the first and fifth weeks), liraglutid＋hUC-MSCs group (treated with liraglutide and hUC-MSCs). Liver tissue was procured for histological examination, real-time qRT-PCR and Western blot analysis. After treatment, liraglutide and hUC-MSCs reduced serum ALT and AST levels, alleviate liver inflammation and improved liver histopathology. The expressions of inflammatory cytokines, TLR4 and NF-κB in serum and liver were significantly inhibited, particularly in the combination treatment group. Eight weeks after liraglutide or hUC-MSCs administration, FBG, HbA1c, HOMA-IR, ALT, AST, Liver wet eight and hepatic TLR4, NF-κB, IL-6, TNF-α, 8-OHdG mRNA and proteins were significantly decreased, and the levels of SOD expression were significantly increased in three treatment groups compared with T2DM/NAFLD group. This study suggests that liraglutide in combination with hUC-MSCs could significantly improve glycolipid metabolism, insulin resistance and liver injury in T2DM/NAFLD rats. Its mechanism may be related to the down-regulation of the TLR4/NF-κB inflammatory pathway and improvement in oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Combined Modality Therapy; Cytokines; Diabetes Mellitus, Type 2; Humans; Inflammation; Liraglutide; Liver; Liver Neoplasms; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; NF-kappa B; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Rats, Sprague-Dawley; Superoxide Dismutase; Toll-Like Receptor 4; Umbilical Cord

The aim of the study was to determine whether serum thymosin beta4 (Tβ4) can be a useful noninvasive biomarker to differentiate between nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver (NAFL).. The study included 24 NAFL patients and 21 NASH patients. The levels of Tβ4, 8-hydroxydeoxyguanosine acid (8-OhdG), liver function parameters, blood lipid, and glucose were detected in the venous blood of all patients. The NAFLD histological activity score (NAS) was examined in biopsy specimens from all patients. Statistical analysis was performed in order to find differences between the two abovementioned groups. In addition, receiver operator characteristic (ROC) analyses for alanine aminotransferase (ALT) and Tβ4 levels were performed in NAFL and NASH patients and the cut-off value was determined. Associations between the variables were tested using correlation coefficient calculations. Statistical significance was set at a p value of < 0.05.. Serum Tβ4 content was 5.12 ± 1.87 mg/l in the NAFL group and 2.98 ± 1.35 mg/l in the NASH group (p < 0.001). Serum Tβ4 content and NAS, histological features of hepatic steatosis, lobular inflammation and ballooning, ALT, glucose and 8-OhdG levels were negatively correlated (p < 0.05 for all) in the NASH group. The correlation coefficient values were -0.530, -0.562, -0.574, -0.438, -0.446, -0.426 and -0.563, respectively. On the basis of ROC analysis, the best predictive Tβ4 cut-off value for detecting NASH was 3.94 mg/l (85.7% sensitivity and 79.2% specificity, which were higher than those of ALT).. Serum Tβ4 level can be used as a biomarker for the diagnosis of NASH and was negatively correlated with the oxidation state of the liver.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aspartate Aminotransferases; Biomarkers; Deoxyguanosine; Diagnosis, Differential; Female; Humans; Liver; Liver Function Tests; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Thymosin

The aim of the present study was to elucidate whether the administration of antioxidant-rich nutrients, including branched-chain amino acids (BCAAs), microelements, and vitamins, both alone and in combination, has a positive impact on liver function in a nonalcoholic steatohepatitis (NASH) mouse model and identify the mechanisms underlying these effects.. Seven-week-old male KKAy mice fed a methionine- and choline-deficient diet (MCD) for 4 weeks were divided into 7 groups and fed the following planned diets for another 4 weeks: group A (normal diet), group B (MCD; control), group C (MCD with rich microelements), group D (MCD with rich BCAAs), group E (MCD with rich microelements and BCAAs), and group F (MCD with rich microelements, BCAAs, and vitamins). We then conducted biochemical assays, histological analyses, immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4-hydroxy-2'-nonenal (4-HNE), and Western blotting for insulin glucose signaling, lipid metabolism, and endoplasmic reticulum (ER) stress-related signaling in liver specimens obtained from mice in each group.. The morphometric grades of all NASH-related findings and the mean degree of 8-OHdG immunolocalization in groups D-F were significantly lower than those observed in group B. The expression levels of insulin receptor β subunit (IRβ) and p-elF in groups E and F and those of phosphatidyl-inositol 3 kinase (PI3K85), p-AcelCoA, and PERK in group F were similar to those noted in group A.. The administration of a combination of antioxidant-rich nutrients, including BCAAs and microelements, is likely to suppress the progression of NASH by reducing oxidative stress, primarily via the downregulation of the ER stress pathway.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Amino Acids, Branched-Chain; Animals; Antioxidants; Choline; Deoxyguanosine; Diet; Dietary Supplements; Endoplasmic Reticulum; Liver; Male; Methionine; Mice; Micronutrients; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Receptor, Insulin; Vitamins

Non-alcoholic fatty liver disease (NAFLD) is an increasing cause of hepatocellular carcinoma (HCC). Previously, we reported that DNA oxidation induced epigenetic alteration of tumor suppressor genes (TSGs) and contributed to HCC emergence. Here, we examine the associations between clinicopathological characteristics of NAFLD and advanced oxidative DNA damage that is associated with TSG methylation in the NAFLD liver.. Liver biopsies from 65 NAFLD patients were analyzed for clinicopathological features and oxidative DNA damage using immunohistochemistry of 8-hydroxydeoxyguanosine (8-OHdG). Abnormal DNA methylation in the promoters of 6 TSGs, HIC1, GSTP1, SOCS1, RASSF1, CDKN2A, and APC, was examined using MethyLight. Associations between clinicopathological characteristics, methylation of TSGs, and accumulation of 8-OHdG were analyzed.. We found that aspartate aminotransferase/alanine aminotransferase ratio, the fibrosis-4 index, and serum α-fetoprotein (AFP) level were associated with degree of 8-OHdG, and AFP was an independent factor among them (P = 0.0271). Regarding pathological findings, hepatocellular ballooning and stage of fibrosis were also associated with oxidative DNA damage (P = 0.0021 and 0.0054); ballooning was an independent risk for detecting high degree of 8-OHdG in hepatocytes (odds ratio 7.38, 95% confidence interval 1.41-49.13, P = 0.0171). Accumulation of methylated TSGs was significantly associated with deposition of 8-OHdG (P = 0.0362).. Patients with high serum AFP and high degree of ballooning showed accumulation of oxidative DNA damage that could be a seed of DNA methylation responsible for hepatocarcinogenesis. These characteristics could be risk of HCC; such patients require urgent intervention such as lifestyle modification.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; alpha-Fetoproteins; Biopsy; Carcinoma, Hepatocellular; Cell Transformation, Neoplastic; Deoxyguanosine; DNA Damage; DNA Methylation; Female; Gene Expression Regulation; Genes, Tumor Suppressor; Hepatocytes; Humans; Liver; Liver Neoplasms; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Oxidation-Reduction; Promoter Regions, Genetic

The aim of this study was to evaluate the role of NADPH oxidase (NADPHox) in the pathogenesis of oxidative phosphorylation (OXPHOS) dysfunction as found in mice fed a high-fat diet (HFD). C57BL/6J mice were distributed in four groups: WT/SCD: six wild-type (WT) mice fed a standard chow diet (SCD); WT/HFD, six WT mice fed a HFD; NOX2(-/-)/SCD, six NADPHox-deficient mice on a SCD; (4) NOX2(-/-)/HFD, six NADPHox-deficient mice on a HFD. After 32 weeks, we studied the liver for: histology; OXPHOS complex activity; fully assembled OXPHOS complexes and their subunits; gene expression of OXPHOS subunits; oxidative and nitrosative stress; and oxidative DNA damage. In the liver of WT/HFD mice, we found a significant decreased in the activity of all OXPHOS complexes, in fully assembled complexes, in the amount of OXPHOS subunits, and in gene expression of mitochondrial DNA-encoded subunits. 8-hydroxy-2'-deoxyguanosine was only increased in mitochondrial DNA. The liver of NOX(-/-)/HFD mice showed mild steatosis but no non-alcoholic steatohepatitis (NASH) lesions were found. OXPHOS activity, OXPHOS subunits, and assembly of subunits into OXPHOS complexes were normal in these mice. We conclude that this study shows that NADPH deficiency protects mice from developing OXPHOS dysfunction and NASH caused by a HFD.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adenosine Diphosphate; Adenosine Triphosphate; Animals; Deoxyguanosine; Diet, High-Fat; Disease Models, Animal; DNA Damage; ERRalpha Estrogen-Related Receptor; Gene Expression; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; NADPH Oxidase 2; Non-alcoholic Fatty Liver Disease; Oxidative Phosphorylation; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Receptors, Estrogen

Free iron in the liver is believed to facilitate the formation of reactive oxygen species (ROS), including hydroxyl radicals (*OH), which cause oxidative damage of numerous cellular components such as lipids, proteins, and nucleic acids, and also upregulate collagen synthesis. The *OH radical is known to generate promutagenic bases such as 8-hydroxy-2-deoxyguanosine (8-OHdG). In cases with chronic hepatitis C, long-term iron reduction therapy reduced the activity of hepatitis, suppressed fibrosis, and prevented hepatocarcinogenesis. In nonalcoholic steatohepatitis (NASH) livers, hepatic iron accumulation as well as oxidative DNA damage significantly increased. Humoral factor(s) in NASH serum may upregulate DMT1 expression in small intestine. Iron reduction therapy for NASH patients has a potential to reduce disease activity as well as hepatic oxidative damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Deoxyguanosine; Hepatitis C, Chronic; Humans; Iron; Jejunum; Non-alcoholic Fatty Liver Disease; Oxidative Stress

The rate of onset of hepatocellular carcinoma (HCC) in patients with nonalcoholic steatohepatitis (NASH) has been reported recently to be comparable to that of patients with chronic hepatitis C. However, the precise mechanism contributing to carcinogenesis in the former remains unclear. Although increased oxidative stress is presumed to play a role in carcinogenesis in patients with NASH, this relationship remains to be directly proven. In this study, we investigated the involvement of oxidative DNA damage in hepatocarcinogenesis in patients with NASH.. Patients with nonalcoholic fatty liver disease who were treated at our university hospital were eligible for enrolment in the study(n = 49). The study cohort included 30 patients with NASH without HCC (NASH without HCC), six HCC patients with NASH (NASH-HCC), and 13 patients with simple steatosis. Quantitative immunohistochemistry with a KS-400 image analyzing system was used for 8-hydroxy-2'-deoxyguanosine (8-OHdG) detection.. The 8-OHdG content in the liver tissue of NASH-HCC patients was significantly different from that in the other patients. The median immunostaining intensity was 8.605 in the NASH-HCC cases, which was significantly higher than that in the cases of NASH without HCC (4.845; P = 0.003). Multivariate analysis using hepatic 8-OHdG content as a factor in addition to age and fasting blood sugar revealed a significant difference in clinicopathological factors between NASH-HCC and NASH without HCC cases. Old age (P = 0.015) and high relative immunostaining intensity for intrahepatic 8-OHdG (P = 0.037) were identified as independent factors.. 8-OHdG content in liver tissue may serve a marker of oxidative stress and could be a particularly useful predictor of hepatocarcinogenesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aged, 80 and over; Aldehydes; Carcinoma, Hepatocellular; Cell Transformation, Neoplastic; Deoxyguanosine; DNA Damage; DNA, Neoplasm; Fatty Liver; Female; Humans; Liver; Liver Neoplasms; Male; Middle Aged; Neoplasm Staging; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Young Adult

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of a metabolic syndrome characterized by accumulation of hepatic fat, inflammation and varying degrees of fibrosis. Angiotensin (AT)-II has been reported to play a role in the establishment of NASH. This study examined the effects of an AT-II receptor blocker, irbesartan, on NASH using fatty liver Shionogi (FLS)-ob/ob male mice as the closest animal model of human metabolic syndrome-related NASH. Irbesartan (30 mg/kg/day) was orally administered to FLS-ob/ob mice for 12 weeks (irbesartan group). The effects of irbesartan on steatohepatitis were examined using factors including steatosis, fibrosis, inflammation and oxidative stress. The areas of hepatic fibrosis and hepatic hydroxyproline content were significantly lower in the irbesartan group compared to controls. The areas of α-smooth muscle actin-positivity and F4/80-positive cells were significantly decreased in the irbesartan group. The percentage of 8-hydroxy-2-deoxyguanosine (8-OHdG)-positive cells and 8-OHdG DNA content were significantly decreased in the irbesartan group compared to controls. Levels of RNA expression for procollagen I, transforming growth factor β1, tumor necrosis factor-α, sterol regulatory element-binding protein 1c and fatty acid synthase were significantly lower in the irbesartan group compared to controls. In contrast, the gene expression of peroxisome proliferator activated receptor-α was significantly higher in the irbesartan group compared to controls. Irbesartan administration improved hepatic steatosis and attenuated the progression of hepatic fibrosis by inhibiting the activation of hepatic stellate cells and Kupffer cells and reducing oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Actins; Angiotensin II Type 1 Receptor Blockers; Animals; Biphenyl Compounds; Collagen Type I; Deoxyguanosine; Fatty Acid Synthases; Fatty Liver; Hepatic Stellate Cells; Inflammation; Irbesartan; Liver Cirrhosis; Male; Mice; Mice, Obese; Non-alcoholic Fatty Liver Disease; Obesity; Oxidative Stress; PPAR alpha; RNA, Messenger; Sterol Regulatory Element Binding Protein 1; Tetrazoles; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha