Feruze Yilmaz Enc

SIRT1 as a potential therapeutic target for treatment of nonalcoholic fatty liver disease

Summary Sirtuins are members of the silent information regulator 2 (Sir2) family, a group of Class III histone/protein deacetylases. There are 7 different sirtuins in mammals (SIRT1-7), of which SIRT1 is the best known and most studied. SIRT1 is responsible for the regulation of protein activation by means of deacetylating a variety of proteins that play important roles in the pathophysiology of metabolic diseases. Recently, it has been shown that SIRT1 plays key roles in the regulation of lipid and glucose homeostasis, control of insulin secretion and sensitivity, antiinflammatory effects, control of oxidative stress and the improvements in endothelial function that result due to increased mitochondrial biogenesis and β-oxidation capacity. Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease, and it has been accepted as the hepatic component of metabolic syndrome. Recent studies have shown that SIRT expression in the liver is significantly decreased in an NAFLD model of rats fed a high-fat diet, and moderate SIRT1 overexpression protects mice from developing NAFLD. In addition to resveratrol, a natural SIRT1 activator, small-molecule pharmacologic SIRT1 activators have positive effects on metabolic diseases. These effects are particularly promising in the case of diabetes mellitus, for which phase studies are currently being performed. With this information, we hypothesized that the pharmacologic activation of SIRT1, which has been implicated in the pathogenesis of NAFLD, will be a potential therapeutic target for treating NAFLD. In this paper, we review the metabolic effects of SIRT1 and its association with the pathophysiology of NAFLD.

Relation of epicardial adipose tissue and carotid intima-media thickness in patients with nonalcoholic fatty liver disease.

Objective Currently, nonalcoholic fatty liver disease (NAFLD) itself has been accepted as an atherosclerotic risk factor and related to increased cardiovascular disease risk. In this study, we aimed to investigate the relationship of epicardial fat thickness (EFT), a parameter associated with atherosclerosis in recent years, with carotid artery intima-media thickness (C-IMT), another parameter of subclinical atherosclerosis. Design and methods We investigated 57 patients with biopsy-proven NAFLD and 30 age-matched and sex-matched controls. EFT was obtained by transthoracic echocardiography and C-IMT was evaluated by an ultrasonographic measurement using a linear type B-mode probe. Results EFT and C-IMT were significantly higher in NAFLD patients compared with the controls (EFT: 0.58±0.18 vs. 0.36±0.17 cm, P<0.001 and C-IMT: 0.64±0.1 vs. 0.52±0.1 mm, P<0.001, respectively). We found a statistically significant correlation between EFT and BMI, C-IMT, waist circumference, homeostasis model assessment of insulin resistance, and nonalcoholic steatohepatitis scores in both groups. Stepwise regression analysis showed that C-IMT (&bgr;=0.36, t=2.86, P=0.006) and waist circumference (&bgr;=0.3, t=2.44, P=0.018), in the order they entered into the model, were independent predictors of EFT in patients with NAFLD. Conclusion Our findings indicate that EFT and C-IMT were significantly higher in patients with NAFLD compared with the controls and waist circumference and C-IMT are independent predictors for EFT in patients with NAFLD.

TLR4 gene polymorphism in patients with nonalcoholic fatty liver disease in comparison to healthy controls.

OBJECTIVES Recent studies have suggested that bacterial overgrowth and endotoxemia along with its receptor, Toll-like receptor 4 (TLR-4), play a role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The present study was designed to test and evaluate the TLR4 gene polymorphism in patients with NAFLD in comparison to healthy controls. METHODS A total of 119 patients [mean (standard deviation, SD) age 43.4 (11.5) years, 55.5% were males] with NAFLD and 80 healthy controls [mean (SD) age 40.9 (8.1) years, 67.5% were females)] were evaluated in terms of patient demographics, anthropometrics, blood biochemistry, liver histology, and ultrasonographic (USG) findings. Histological evaluation was performed in 111 patients, and blood samples were collected from 119 patients with NAFLD and 80 healthy persons. Allelic variants of TLR4 (Asp299Gly and Thr399Ile) were assayed by real-time PCR. Genomic DNA was amplified using FAM/VIC primers specific for allelic variants of TLR4 Asp299Gly and Thr399Ile with real-time PCR. Amplicons were analyzed with high-resolution melting on a Light Cycler 480 for detecting different melting patterns of polymorphic and wild-type alleles. RESULTS The number of the subjects with heterozygous mutation at genotype 299 (Asp299Gly) was significantly lower in the NAFLD than in the control group (23.8 vs. 10.9%, P=0.027). Logistic regression analysis revealed that female gender [odds ratio (OR)=2.984, 95% confidence interval (CI) 1.561-5.360, P=0.001] and heterozygous (Asp299Gly) mutation at codon 299 (OR=2.998, 95% CI 1.325-6.783, P=0.008) were the significant predictors of higher likelihood of TRL4 gene polymorphism-related prevention of NAFLD. CONCLUSIONS As the first-time-in-humans controlled study related to investigation of TLR4 gene polymorphism in NAFLD, our findings contribute to the available data that TLR-4 signaling is pivotal for the pathogenesis of NASH and indicate that the TLR4 codon 299 heterozygous gene mutation (Asp299Gly) in humans may have a preventive role against the genesis of NAFLD.

Association of human leukocyte antigen DQB1 and DRB1 alleles with chronic hepatitis B

AIM To investigate the effect of human leukocyte antigen (HLA) DRB1 and DQB1 alleles on the inactive and advanced stages of chronic hepatitis B. METHODS Patient records at a single institutions hepatology clinic were reviewed. Demographic data, laboratory results, endoscopy results, virological parameters, biopsy scores and treatment statuses were recorded. In total, 355 patients were eligible for the study, of whom 226 (63.7%) were male. Overall, 82 (23.1%) were hepatitis B early antigen (HBeAg) positive, 87 (24.5%) had cirrhosis, and 66 (18.6%) had inactive disease. The presence of DQB1 and DRB1 alleles was determined by polymerase chain reaction with sequence-specific primers. The distribution of the genotyped alleles among patients with cirrhosis and patients with chronic active hepatitis was analyzed. RESULTS The most frequent HLA DQB1 allele was DQB1*03:01 (48.2%), and the most frequent HLA DRB1 allele was DRB1*13/14 (51.8%). DQB1*05:01 was more frequent in patients with active disease than in inactive patients (27% vs 9.1%; P = 0.002, Pc = 0.026). DRB1*07 was rare in patients with cirrhosis compared with non-cirrhotics (3.4% vs 16%; P = 0.002, Pc = 0.022). Older age (P < 0.001) and male gender (P = 0.008) were the other factors that affected the presence of cirrhosis. In a multivariate logistic regression analysis, DRB1*07 remained a significant negative predictor of cirrhosis (P = 0.015). A bioinformatics analysis revealed that a polymorphic amino acid sequence in DRB1*07 may alter interaction with the T-cell recognition site. CONCLUSION This study demonstrates that HLA alleles may influence cirrhosis development and disease activity in Turkish chronic hepatitis B patients.

Association of Serum Lipoprotein-Associated Phospholipase A2 Level with Nonalcoholic Fatty Liver Disease

BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is one of the most common causes of chronic liver disease, worldwide. Lipoprotein-associated phospholipase A2 (Lp-PLA2) was recently characterized as a novel inflammatory biomarker that is correlated with several components constituting the metabolic syndrome. METHODS In this study, we determined the serum levels of Lp-PLA2 in patients with definite nonalcoholic steatohepatitis (NASH, n=25), borderline NASH (n=22), simple fatty liver (n=10), and healthy controls without evidence of liver disease (n=38). The levels of Lp-PLA2 were measured by enzyme-linked immunosorbent assay and compared in the four study groups. Moreover, concentrations of Lp-PLA2 were assessed in relation to the general characteristics of the study participants and the results of liver biopsy. RESULTS Concentrations of Lp-PLA2 were significantly higher in patients with definite NASH (161.8±0.9 μg/L, P<0.001), borderline NASH (135.4±47.7 μg/L, P=0.001), and simple fatty liver (132.4±46.2 μg/L, P=0.042) compared with healthy controls (86.2±40.7 μg/L). Furthermore, the serum Lp-PLA2 level was strongly associated to histological steatosis scores in patients with NAFLD (β=0.32, t=2.50, P=0.016). CONCLUSION Although subject to future confirmation, our data suggest that Lp-PLA2 levels are elevated in NAFLD.

Concentrations of connective tissue growth factor in patients with nonalcoholic fatty liver disease: association with liver fibrosis.

Aim: In this study, we aimed to investigate the relationship between the histological fibrosis stage of nonalcoholic fatty liver disease (NAFLD) and serum connective tissue growth factor (CTGF) to determine the usefulness of this relationship in clinical practice. Methods: Serum samples were collected from 51 patients with biopsy-proven NAFLD and 28 healthy controls, and serum levels of CTGF were assayed by ELISA. Results: Levels of CTGF were significantly higher in patients with NAFLD compared with controls (P = 0.001). The serum CTGF levels were significantly increased, that correlated with histological fibrosis stage, in patients with NAFLD [in patients with no fibrosis (stage 0) 308.2 ± 142.9, with mild fibrosis (stage 1–2) 519.9±375.2 and with advanced fibrosis (stage 3–4) 1353.2 ± 610 ng/l, P < 0.001]. Also serum level of CTGF was found as an independent predictor of histological fibrosis stage in patients with NAFLD (β = 0.662, t = 5.6, P < 0.001). The area under the ROC curve was estimated 0.931 to separate patients with severe fibrosis from patients with other fibrotic stages. Conclusion: Serum levels of CTGF may be a clinical utility for distinguishing NAFLD patients with and without advanced fibrosis.

Impaired Gallbladder Motility and Increased Gallbladder Wall Thickness in Patients with Nonalcoholic Fatty Liver Disease.

Background/Aims Nonalcoholic fatty liver disease (NAFLD) is currently the most common chronic liver disease worldwide. Along with the increase in the incidence of NAFLD and associated obesity, an increase in gallbladder disease (GD) has been noted. This has led to the identification of a new disease entity called fatty GD. There is a gap in the literature on the dynamics of gallbladder function in patients with NAFLD. Methods An observational case-control study, a total of 50 patients with biopsy proven NAFLD without gallbladder stone/sludge and 38 healthy comparison subjects were enrolled. Fasting, postprandial gallbladder volumes (PGV), gallbladder ejection fraction (GEF), and fasting gallbladder wall thickness (FGWT) were measured by real-time 2-dimensional ultrasonography. Results Fasting gallbladder wall thickness, fasting gallbladder volumes and PGV were significantly higher in patients with NAFLD than control subjects (P < 0.001, P = 0.006, and P < 0.001, respectively). Gallbladder ejection fraction was significantly lower in the NAFLD group than the controls (P = 0.008). The presence of NAFLD was an independent predictor for GEF, PGV, and FGWT. Also, steatosis grade was an independent predictor for GEF, and GEF was significantly lower in the nonalcoholic steatohepatitis (NASH) subgroup than the controls. Conclusions Gallbladder dysfunction and increase in gallbladder wall thickness exists in asymptomatic (without stone/sludge and related symptoms) patients with NAFLD and are useful in identifying fatty GD. Measurement of these variables in NAFLD patients may be useful in identifying those at higher risk for GD.

Therapeutic success with bismuth-containing sequential and quadruple regimens in Helicobacter pylori eradication

BACKGROUND AND STUDY AIMS The success rate of Helicobacter pylori (H. pylori) eradication with the classical triple therapy is gradually declining. In this study, we aimed to compare and assess the efficacies of six different eradication regimens including sequential protocols. PATIENTS AND METHODS Endoscopically confirmed nonulcer dyspepsia patients were enrolled. H. pylori presence was determined either histologically or by a rapid urease test. Treatment-naive patients were randomly assigned to an either one of three 10-day (OAC, OTMB, and OACB) or one of three sequential protocols (OA+OCM, OA+OCMB, and OA+OMDB) (O=omeprazole, A=amoxicillin, C=clarithromycin, T=tetracycline, M=metronidazole, B=bismuth, D=doxycycline). The eradication was assessed 6-8weeks after the completion of the treatment by a 14C-urea breath test. RESULTS In total, 301 patients were included. Fifty-two percent of the participants (n=157) were female, and the mean age was 44.9years (range=18-70). The intention to treat (ITT) and per protocol (PP) eradication rate for each regimen is as follows: OAC (ITT=61.2%, PP=75%), OTMB (83.3%, 87%), OACB (76.5%, 79.6%), OA+OCM (72.3%, 73.9%), OA+OCMB (82.7%, 89.6%), and OA+OMDB (59.3%, 65.3%). Smoking significantly affected the eradication rate (P=0.04). CONCLUSION In this study, OTMB and OA+OCMB were significantly superior to the triple therapy and succeeded to reach the eradication rate proposed by the Maastricht consensus (over 80%). These two bismuth-containing regimens could be considered for first-line therapy in the regions with high clarithromycin resistance.

Plasma fibrinogen-like protein 2 levels in patients with non-alcoholic fatty liver disease.

BACKGROUND/AIMS Fibrinogen-like protein 2 (fgl2), has recently been identified as a new member of the fibrinogen-like family of proteins. In this study we assayed plasma levels of fgl2 in patients with biopsy proven non-alcoholic fatty liver disease (NAFLD) and examined their association with clinical, biochemical and histological phenotypes. METHODOLOGY Levels of plasma fgl2 were measured by enzyme linked immunosorbent assay and compared between the study groups. Moreover, concentrations of fgl2 were assessed in relation to the general characteristics of the study participants and the results of the liver biopsy. RESULTS Levels of fgl2 were significantly higher in patients with definite non-alcoholic steatohepatitis (NASH) (788±190pg/mL, p<0.001) and borderline NASH (710 ± 140pg/mL, p<0.001) compared with controls (515±174pg/mL). No significant differences were found in patients with simple steatosis (649 ± 162pg/mL) as compared with controls. There were no associations between the plasma fgl2 levels with the fibrosis stage and steatosis grade. CONCLUSIONS Although subject to future confirmation, our data suggest that fgl2 levels are elevated in the more severe forms of NAFLD.

Evaluation of depression, anxiety, alexithymia, attachment, social support and somatization in functional dyspepsia

ABSTRACT AIM: The psychiatric and psychosocial aetiology of Functional dyspepsia is not well known. In the present study, our aim is to determine the relative contributions of psychiatric predictors – i.e. depression, anxiety, somatization, alexithymia – in relation with socio-psychological factors, specifically their personal characteristics (i.e. emotional attachment) and perceived social support, in distinguishing FD from organic dyspepsia and healthy samples. MATERIAL AND METHODS: An estimated 30 functional dyspepsia, 29 organic dyspepsia patients who were admitted to our gastroenterology outpatient clinic and 27 healthy controls were enrolled to our study. Beck Depression Inventory, Toronto Alexithymia Scale, Adult Attachment Scale, State-Trait Anxiety Inventory, Multidimensional Scale of Perceived Social Support and somatization sub-scale of Symptom Checklist-90 were provided to all patients and healthy controls. All participants were examined by a gastroenterologist and a psychiatrist. RESULTS: Healthy controls were younger than organic dyspepsia group and women/men rate was lower in organic dyspepsia than other two groups. Depression score was higher in functional dyspepsia group than in healthy controls and functional dyspepsia group’s attachment syle was more secure than that of the healthy control group. Somatization rate was seen higher in functional dyspepsia group with psychiatric examination. There was no significant difference seen in anxiety, alexithymia and social support between the three groups. DISCUSSION: Anxious-avoidant attachment profile as well as the higher propensity to have depressive and anxiety symptoms might be critical psychiatric and psychosocial factors underlying FD’s aetiology. A multidisciplinary approach is needed in the follow up of functional dyspepsia patients. Psychological evaluation and treatment would increase the life quality of dyspepsia patients.