J.T. Stefano

Combination of N‐acetylcysteine and metformin improves histological steatosis and fibrosis in patients with non‐alcoholic steatohepatitis

Aim:  There is no proven medical therapy for the treatment of non‐alcoholic steatohepatitis (NASH). Oxidative stress and insulin resistance are the mechanisms that seem to be mostly involved in its pathogenesis. The aim of our study was to evaluate the efficacy of N‐acetylcysteine (NAC) in combination with metformin (MTF) in improving the aminotransferases and histological parameters (steatosis, inflammation, hepatocellular ballooning, and fibrosis) after 12 months of treatment.

A rodent model of NASH with cirrhosis, oval cell proliferation and hepatocellular carcinoma

BACKGROUND/AIMS Hepatocellular carcinoma (HCC) is a well recognized complication of advanced NASH (non-alcoholic steatohepatitis). We sought to produce a rat model of NASH, cirrhosis and HCC. METHODS Adult Sprague-Dawley rats, weighing 250-300g, were fed a choline-deficient, high trans-fat diet and exposed to DEN in drinking water. After 16 weeks, the animals underwent liver ultrasound (US), sacrifice and assessment by microscopy, immunohistochemistry and transmission electron microscopy (TEM). RESULTS US revealed steatosis and focal lesions in 6 of 7. All had steatohepatitis defined as inflammation, advanced fibrosis and ballooning with Mallory-Denk bodies (MDB) with frank cirrhosis in 6. Areas of more severe injury were associated with anti-CK19 positive ductular reaction. HCC, present in all, were macro-trabecullar or solid with polyhedral cells with foci of steatosis and ballooned cells. CK19 was positive in single or solid nests of oval cells and in neoplastic hepatocytes. TEM showed ballooning with small droplet fat, dilated endoplasmic reticulum and MDB in non-neoplastic hepatocytes and small droplet steatosis in some cancer cells. CONCLUSIONS This model replicated many features of NASH including steatohepatitis with ballooning, fibrosis, cirrhosis and hepatocellular carcinoma. Oval cell proliferation was evident and the presence anti-CK 19 positivity in the cancer suggests oval cell origin of the malignancy.

Intake of trans Fatty Acids Causes Nonalcoholic Steatohepatitis and Reduces Adipose Tissue Fat Content

We investigated the effects of dietary trans fatty acids, PUFA, and SFA on body and liver fat content, liver histology, and mRNA of enzymes involved in fatty acid metabolism. LDL receptor knockout weaning male mice were fed for 16 wk with diets containing 40% energy as either trans fatty acids (TRANS), PUFA, or SFA. Afterwards, subcutaneous and epididymal fat were weighed and histological markers of nonalcoholic fatty liver disease (NAFLD) were assessed according to the Histological Scoring System for NAFLD. PPARalpha, PPARgamma, microsomal triglyceride transfer protein (MTP), carnitine palmitoyl transferase 1 (CPT-1), and sterol regulatory element binding protein-1c (SREBP-1c) mRNA were measured by quantitative RT-PCR. Food intake was similar in the 3 groups, although mice fed the TRANS diet gained less weight than those receiving the PUFA diet. Compared with the PUFA- and SFA-fed mice, TRANS-fed mice had greater plasma total cholesterol (TC) and triglyceride (TG) concentrations, less epididymal and subcutaneous fat, larger livers with nonalcoholic steatohepatitis (NASH)-like lesions, and greater liver TC and TG concentrations. Macrosteatosis in TRANS-fed mice was associated with a higher homeostasis model assessment of insulin resistance (HOMA(IR)) index and upregulated mRNA related to hepatic fatty acid synthesis (SREBP-1c and PPARgamma) and to downregulated MTP mRNA. Diet consumption did not alter hepatic mRNA related to fatty acid oxidation (PPARalpha and CPT-1). In conclusion, compared with PUFA- and SFA-fed mice, TRANS-fed mice had less adiposity, impaired glucose tolerance characterized by greater HOMA(IR) index, and NASH-like lesions due to greater hepatic lipogenesis. These results demonstrate the role of trans fatty acid intake on the development of key features of metabolic syndrome.

Association of polymorphisms of glutamate‐cystein ligase and microsomal triglyceride transfer protein genes in non‐alcoholic fatty liver disease

Background and Aims:  Although the metabolic risk factors for non‐alcoholic fatty liver disease (NAFLD) progression have been recognized, the role of genetic susceptibility remains a field to be explored. The aim of this study was to examine the frequency of two polymorphisms in Brazilian patients with biopsy‐proven simple steatosis or non‐alcoholic steatohepatitis (NASH): −493 G/T in the MTP gene, which codes the protein responsible for transferring triglycerides to nascent apolipoprotein B, and −129 C/T in the GCLC gene, which codes the catalytic subunit of glutamate‐cystein ligase in the formation of glutathione.

Effects of hepatitis C virus on cardiovascular risk in infected patients: a comparative study.

The role of hepatitis C virus (HCV) in the pathogenesis of atherosclerosis and cardiovascular events is unclear. The aim of this study was to evaluate the direct effect of HCV on cardiovascular risk and correlate it with pro and anti-inflammatory cytokines in patients with HCV. HCV monoinfected patients, genotype 1, naive, non-obese (BMI<30) and non-diabetics were included and compared to controls (blood donors). Patients with prior diagnosis of cardiovascular diseases, hypertension, chronic renal failure, cancer and chronic use of lipid-lowering drugs or immunosuppressants were excluded. Age, BMI, systolic blood pressure (SBP) and diastolic (DBP), fasting glucose and lipid levels were determined. Serum cytokines (IL-6, IL-10 and TNF-α) and Framingham score were also evaluated. 62 HCV patients, 34 (54.8%) were males and none of them was smoking. The Framingham scores (median and 25th and 75th percentiles) were 12% (6.5-14%), showing an intermediate cardiovascular risk in patients with HCV. There was significant direct correlation between Framingham and total cholesterol (p=0.043) and DBP (p=0.007). HDL-C (p=0.002) was inversely correlated with the Framingham score. HCV patients had higher levels of proinflammatory cytokines (IL-6 and TNF-α) compared to controls (p<0.0001) and the relation of proinflammatory/anti-inflammatory TNF-α/IL10 and IL-6/IL10 were higher in HCV patients (p<0.01). The Framingham score was directly correlated to IL-6 and TNF-α, but differences were not statistically significant. Patients with HCV monoinfected, nonobese, naïve and non diabetic have an intermediate cardiovascular risk, as measured by the Framingham score and high levels of proinflammatory cytokines (IL-6 and TNF).

Microsomal triglyceride transfer protein and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is currently one of the most common forms of liver disease, covering cases from simple steatosis without inflammation, to cases of steatohepatitis and fibrosis, and may lead to liver cirrhosis and hepatocellular carcinoma. The pathophysiology of nonalcoholic fatty liver disease is based on multiple events; changes in the secretion of lipoproteins can lead to steatosis. Liver lipid secretion is mediated by apoB100 and microsomal triglyceride transfer protein (MTP). The pharmacological suppression of MTP is suggested as a possible treatment for hyperlipidemia, although the upregulation of this protein can be a treatment for nonalcoholic steatohepatitis.

Advanced glycated albumin isolated from poorly controlled type 1 diabetes mellitus patients alters macrophage gene expression impairing ABCA-1-mediated reverse cholesterol transport

We evaluated the effects of albumin isolated from control individuals and from patients with poorly controlled type 1 diabetes mellitus on macrophage gene expression and on reverse cholesterol transport.

Pro- and Anti-inflammatory Cytokines in Steatosis and Steatohepatitis

BackgroundFatty liver disease is a problem in both bariatric patients and in patients with moderate obesity. Tumor necrosis factor (TNF)-α has been frequently measured in nonalcoholic steatohepatitis (NASH) with or without diabetes, but less is known about interleukin (IL)-6 and IL-10.MethodsModerately obese patients (n = 80) with histologically proven steatosis (n = 29) and NASH (n = 51) were recruited. Serum levels of cytokines were documented along with clinical information. The aim was to identify the correlates of such biomolecules in a stable population.ResultsDiabetes tended to be more associated with NASH (52.5% instead of 41.4%, P = 0.015), with no difference of age, gender, or body mass index regarding steatosis. For the entire population, cytokine changes were not significant, including TNF-α and IL-6. In diabetics only, all markers tended to diminish with NASH, especially IL-10 (P = 0.000). IL-10 correlated with homeostatic model assessment index (P = 0.000) and other variables of glucose homeostasis in diabetes, thus representing a major marker of the disease.Conclusions(1) Generally inconsistent changes in pro- and anti-inflammatory cytokines occurred when NASH was globally compared to steatosis. (2) In contrast, downregulation of IL-6 and IL-10 was perceived in diabetics with NASH. (3) Arterial hypertension did not play a role in these circumstances. (4) IL-10 maintained strong correlations with glucose metabolism indices. (5) TNF-α could not be incriminated for progressive liver damage, as values failed to increase in NASH. (6) Investigations of IL-10 and other counterregulatory cytokines are lacking in this context and deserve further studies.

Hypocaloric high-protein diet improves clinical and biochemical markers in patients with nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE To investigate the role of hypocaloric highprotein diet, a prospective clinical study was conducted in NAFLD patients. RESEARCH METHODS AND PROCEDURES Pre-versus post-interventional data were analyzed in 48 stable NAFLD patients (submitted to a hypocaloric high-protein diet during 75 days. Variables included anthropometrics (body mass index/ BMI and waist circumference/WC), whole-body and segmental bioimpedance analysis and biochemical tests. Diet compliance was assessed by interviews every two weeks. RESULTS BMI, WC and body fat mass remained relatively stable (-1.3%, -1.8% and -2.5% respectively, no significance). HDL- cholesterol increased (P < 0.05) whereas total, LDL and VLDL cholesterol, triglycerides, aspartate aminotransferase/ AST, gamma glutamyltransferase/GGT, alkaline phosphatase/ AP, fasting blood glucose and glycated hemoglobin/ HbA1c decreased (P < 0.05). When patients were stratified according to increase (22/48, 45.8%) and decrease (21/48, 43.8%) of BMI, association between weight decrease and liver benefit could be elicited in such circumstances for ALT, AP and AST/ALT ratio. No change could be demonstrated in patients who gained weight. Multivariate assessment confirmed that waist circumference, ferritin, triacylglycerol, and markers of glucose homeostasis were the most relevant associated with liver enzymes. DISCUSSION Ours results are consistent with the literature of calorie restriction in the management of NAFLD. Changes in lifestyle and weight loss are recommended for NAFLD patients. European guidelines also support this recommendation. CONCLUSION This is the first study that demonstrated that a high protein, hypocaloric diet were associated with improvement of lipid profile, glucose homeostasis and liver enzymes in NAFLD independent on BMI decrease or body fat mass reduction.

Genetic polymorphisms and oxidative stress in non-alcoholic steatohepatitis (NASH): A mini review.

Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease, thus becoming an epidemic in the Western world with a major impact on public health. NAFLD encompasses a large spectrum of disease ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and may progress to fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The role of genetic polymorphisms is not clear. Evidence supports the hypothesis that genetic factors are involved in the predisposition to NAFLD, and thus should emphasize the polygenic nature of the disease as a limiting factor in these studies. However, the polymorphic allele associated with increased hepatic steatosis appears to be associated with various different combinations of phenotypes, including increase or decrease of the biochemical and clinical parameters. It is possible that SNPs in genes involved in excessive fatty acid oxidation would predispose to NASH. On the other hand, the SNPs could determine the inadequate mitochondrial overload during times of excessive FFA supply. However due to the multiple hits involving some pathways, a brief review of genetic variants on mediators of oxidative stress, inflammation and lipid metabolism pathways is presented. It is clear that the discovery of genetic and environmental associations, robust enough to direct the treatment and to trace specific prevention strategies would only be possible with studies examining the susceptibility of NAFLD in a number of individuals considerably higher than assessed so far. These studies need a large number of well phenotyped cases and controls and certainly require national and international collaboration.