INFLUENCE OF OXIDATIVE STRESS AND OBESITY IN PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS

BackgroundNonalcoholic steatohepatitis is considered the hepatic manifestation of metabolic syndrome and it is particularly associated to the insulin resistance, hypertension, obesity and abnormalities in lipid and glucose metabolism.ObjectiveConsidering the importance of obesity and oxidative stress in the pathophysiology of nonalcoholic steatohepatitis, this study aimed to evaluate the presence and association of the obesity and oxidative stress in this pathology.MethodsFifteen outpatients with nonalcoholic steatohepatitis (nonalcoholic steatohepatitis group), diagnosed according to the histopathological findings from the liver biopsy, and 15 body mass index-matched subjects (non nonalcoholic steatohepatitis group) without nonalcoholic steatohepatitis were included. All volunteers were registered in a Brazilian University Hospital. Nutritional assessment (weight, height, body mass index and waist circumference) and biochemical analysis (fasting glucose, liver enzymes, lipid profile, leptin, superoxide dismutase, glutathione peroxidase, vitamins C and E, catalase and 8-isoprostane) were performed for all the participants. The student t test was used for statistical analysis, with P<0.05 as the significant factor.ResultsNonalcoholic steatohepatitis patients had higher fasting glucose, hepatic enzymes (serum aspartate aminotransaminase, alanine aminotransaminase, gamma glutamyl transferase, alkaline phosphatase), triglycerides and superoxide dismutase and lower glutathione peroxidase values than non nonalcoholic steatohepatitis individuals.ConclusionThis paper demonstrates that only the presence of obesity is not enough to trigger alterations in all the studied biomarkers. Despite the majority of oxidative stress markers being found to be similar in both conditions, the nonalcoholic steatohepatitis subjects could be slightly more affected than the non nonalcoholic steatohepatitis individuals.

Antioxidant effect of apolipoprotein A-I on high-fat diet-induced non-alcoholic fatty liver disease in rabbits

Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized condition that encompasses a spectrum of liver abnormalities. It has been suggested that oxidative stress and lipid peroxidation are key pathophysiological mechanisms in NAFLD. Although an antioxidant effect of apolipoprotein A-I (apoA-I) has been reported, its influence on NAFLD has not been reported. The aim of this study was to determine whether apoA-I could improve the biochemical and histological abnormalities associated with high-fat diet-induced NAFLD through its antioxidant actions in rabbits. Liver damage was evaluated by hepatic coefficient, hepatic lipid assay, liver apparent abnormalities as well as hematoxylin-eosin staining of liver sections. Lipid peroxidation was assessed by measuring malondialdehyde (MDA) level in liver. Oxidative stress was assessed by measuring superoxide dismutase (SOD), glutathione peroxidase (GPx), and inducible nitric oxide synthase (iNOS) activities in serum and liver. Also, the mRNA expressions levels of SOD, GPx, and catalase (CAT) were determined by real-time quantitative polymerase chain reaction method. The results showed that apoA-I (20 or 40 mg/kg/w) was effective in reducing hepatic steatosis, inflammation, hepatic coefficient, and liver total cholesterol, triglyceride, low-density lipoprotein-cholesterol, and MDA levels in high-fat diet rabbits. In addition, apoA-I increased SOD and GPx activities while reducing iNOS activity in serum and liver. Moreover, apoA-I significantly increased the mRNA expression levels of SOD, GPx, and CAT in liver. This study showed that apoA-I exerted protective effects against fatty liver disease in rabbits induced by a high-fat diet, possibly through its antioxidant actions.

Nonalcoholic fatty liver disease and bariatric surgery

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease worldwide. Treatment recommendations for NAFLD are aimed towards weight reduction, thereby reducing insulin resistance. Unfortunately, lifestyle modifications have not yielded long-term success, while durable weight loss is routinely achieved with bariatric surgery. This article reviews the effects of bariatric surgery on patients with NAFLD. In these patients, postsurgical evaluations of liver histology by repeat liver biopsy are hindered by the risk of the procedure and the inherent sample variability, which makes the impact of bariatric surgery on NAFLD difficult to quantify. In longitudinal studies of NAFLD, the biopsy-based evaluations should be augmented by repeated measurements of the noninvasive biomarkers that may provide an insight into the changes in the physiological state of the liver after bariatric or other types of interventions. Nevertheless, currently available tests are not able to provide this type of in-depth outcome measures for these patients.

Amelioration of diet-induced nonalcoholic steatohepatitis in rats by Mn-salen complexes via reduction of oxidative stress

BACKGROUND

Nonalcoholic steatohepatitis (NASH), a progressive stage of nonalcoholic fatty liver disease (NAFLD), is characterized by steatosis (accumulation of triacylglycerols within hepatocytes) along with inflammation and ballooning degeneration. It has been suggested that oxidative stress may play an important role in the progress of NAFLD to NASH. The aim of present study was to determine whether antioxidant supplementations using EUK-8, EUK-134 and vitamin C could improve the biochemical and histological abnormalities associated with diet-induced NASH in rats.

METHODS

NASH was induced in male N-Mary rats by feeding a methionine - choline deficient (MCD) diet. The rats were fed either normal chow or MCD diet for 10 weeks. After NASH development, the MCD-fed rats were randomly divided into four groups of six: the NASH group that received MCD diet, the EUK-8 group which was fed MCD diet plus EUK-8, the EUK-134 group which was fed MCD diet plus EUK-134 and the vitamin C group which received MCD diet plus vitamin C. EUK-8, EUK-134 and vitamin C (30 mg/kg body weight/day) were administered by gavage for eight weeks.

RESULTS

Treatment of MCD-fed rats with salens reduced the sera aminotransferases, cholesterol, low density lipoprotein contents, the extent of lipid peroxidation and protein carbonylation whereas the HDL-C cholesterol levels were significantly increased. In addition, EUK-8 and EUK-134 improved steatosis, ballooning degeneration and inflammation in liver of MCD-fed rats.

CONCLUSION

Antioxidant (EUK-8, EUK-134 and vitamin C) supplementation reduces NASH-induced biochemical and histological abnormalities, pointing out that antioxidant strategy could be beneficial in treatment of NASH.