Insulin resistance and metabolic syndrome in chronic liver diseases: old entities with new implications

Metabolic and Genetic Risk Factors Are the Strongest Predictors of Severity of Alcohol-Related Liver Fibrosis

BACKGROUND & AIMS

Individual risk for developing alcohol-related liver disease (ALD) varies greatly. We hypothesized that metabolic risk factors and genetic polymorphisms predict severity of ALD.

METHODS

Biopsy-controlled, cross-sectional study in patients with a history of excessive drinking. We measured the homeostatic model assessment of insulin resistance (HOMA-IR), plasma triglycerides, high- and low-density lipoproteins (HDL, LDL), and total cholesterol. Moreover, we genotyped four single nucleotide polymorphisms in PNPLA3 (rs738409C>G), TM6SF2 (rs58542926C>T), MBOAT7 (rs641738C>T), and HSD17B13 (rs72613567T>TA). We assessed predictors of higher fibrosis stage using multivariable ordered logistic regression.

RESULTS

Of 325 included patients, 25% had severe fibrosis or cirrhosis and 59% had HOMA-IR ≥2.5. HOMA-IR increased for each fibrosis stage, while there was a similar decrease in LDL and total cholesterol. Individuals with risk variant PNPLA3 rs738409-G or TM6SF2 rs58542926-T had higher fibrosis stage. In multivariable regression, HOMA-IR ≥2.5 (OR = 3.04, 95% CI 1.90-4.87), LDL <2.60 mmol/L (OR = 2.05, 95% CI 1.33-3.16), TM6SF2 rs58542926-T (OR = 1.99, 95% CI 1.17-3.37), age above 50 years (OR = 1.66, 95% CI 1.03-2.70), and PNPLA3 rs738409-G (OR = 1.54, 95% CI 1.11-2.12) independently predicted higher fibrosis stage. Independent predictors of hepatic inflammatory activity were HOMA-IR, active drinking, age, and PNPLA3 risk variant. Active drinking, elevated triglycerides, and PNPLA3 risk variant predicted steatosis.

CONCLUSIONS

Insulin resistance is the strongest predictor of liver fibrosis stage and hepatic inflammation in patients with alcohol-related liver disease. Genetic susceptibility further aggravates this risk. These data highlight the clinical value of detailed metabolic and genetic profiling of patients with excessive alcohol use.

The Differential Roles of T Cells in Non-alcoholic Fatty Liver Disease and Obesity

Non-alcoholic fatty liver disease (NAFLD) constitutes a spectrum of disease states characterized by hepatic steatosis and is closely associated to obesity and the metabolic syndrome. In non-alcoholic steatohepatitis (NASH), additionally, inflammatory changes and hepatocellular damage are present, representing a more severe condition, for which the treatment is an unmet medical need. Pathophysiologically, the immune system is one of the main drivers of NAFLD progression and other obesity-related comorbidities, and both the innate and adaptive immune system are involved. T cells form the cellular component of the adaptive immune system and consist of multiple differentially active subsets, i.e., T helper (Th) cells, regulatory T (Treg) cells, and cytotoxic T (Tc) cells, as well as several innate T-cell subsets. This review focuses on the role of these T-cell subsets in the pathogenesis of NAFLD, as well as the association with obesity and type 2 diabetes mellitus, reviewing the available evidence from both animal and human studies. Briefly, Th1, Th2, Th17, and Th22 cells seem to have an attenuating effect on adiposity. Th2, Th22, and Treg cells seem to decrease insulin resistance, whereas Th1, Th17, and Tc cells have an aggravating effect. Concerning NAFLD, both Th22 and Treg cells appear to have an overall tempering effect, whereas Th17 and Tc cells seem to induce more liver damage and fibrosis progression. The evidence regarding the role of the innate T-cell subsets is more controversial and warrants further exploration.

The effect of antidiabetic medications on non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and is prevalent in more than 50% of patients with type II diabetes. At present, there is no approved therapy for NASH. Until now, the only proven effective interventions in improving biochemical and histological features of NASH, including fibrosis, are weight loss and physical activity even without weight loss. Because of the common epidemiological and pathophysiological features between NAFLD and T2DM, many antidiabetics drugs have been tested in patients with NAFLD over the years. Among these, pioglitazone and liraglutide seem to improve some histological features of NASH but have no clear effect on fibrosis. Metformin has been largely studied in the past years without convincing evidence of improving NAFLD. Data on other compounds such as DDP-4 and SGLT-2 inhibitors are limited. The rational and results of such studies are discussed in the present review.

Animal Models of Nonalcoholic Fatty Liver Disease-A Starter's Guide

Nonalcoholic fatty liver disease (NAFLD) constitutes a major health concern with the increasing incidence of obesity and diabetes in many Western countries, reaching a prevalence of up to 30% in the general population. Animal models have played a vital role in elucidating the pathophysiological mechanisms of NAFLD and continue to do so. A myriad of different models exists, each with its advantages and disadvantages. This review presents a brief overview of these models with a particular focus on the basic mechanisms and physical, biochemical and histological phenotype. Both nutritional and chemically induced, as well as genetic models are examined, including models combining different approaches.

Liver test abnormalities in patients with HIV mono-infection: assessment with simple noninvasive fibrosis markers

Background

Patients with HIV mono-infection may develop chronic liver disease due to a number of factors including hepatic steatosis. We estimated the prevalence and predictors of hepatic steatosis and fibrosis in a cohort of HIV-mono-infected patients with persistently deranged liver function tests.

Methods

Of 2398 consecutive patients at one UK clinical center, 156 (6.5%) had persistently abnormal transaminases in at least two measurements six months apart. We used APRI and FIB4 scores to determine the presence of significant and/or advanced fibrosis in this group as well as its potential associations.

Results

Mean age was 47.5±8.5 years and 91% (142/156) were males. Diabetes mellitus was present in 11% of patients; hypertension in 18%; and dyslipidemia in 52%. Almost all were on antiretroviral therapy (ART) (97%) and most were virologically suppressed (94%). Steatosis was detected by ultrasound in 71% of patients. The prevalence of FIB4≤1.45, 1.46-3.24 and >3.25 was 67%, 29% and 4%, respectively, and that of APRI≤0.5, 0.51-1.49 and >1.5 was 52%, 45% and 3% respectively. In multivariate analysis, only cumulative ART exposure was associated with FIB4>1.45 (odds ratio [OR] 1.008, 95% confidence interval [CI] 1.000-1.016), while APRI>0.5 was associated with higher alanine aminotransferase levels (OR 1.033, 95%CI 1.015-1.510). Twenty patients had a liver biopsy, of whom 13 had non-alcoholic fatty liver disease (NAFLD).

Conclusions

Elevated transaminases are often present in HIV-mono-infected patients and this may be associated with NAFLD and/or ART. Non-invasive screening for the presence of NAFLD and fibrosis in all HIV-mono-infected patients as part of their routine clinical management should be further explored.

Gender differences in liver disease and the drug-dose gender gap

Although gender-based medicine is a relatively recent concept, it is now emerging as an important field of research, supported by the finding that many diseases manifest differently in men and women and therefore, might require a different treatment. Sex-related differences regarding the epidemiology, progression and treatment strategies of certain liver diseases have long been known, but most of the epidemiological and clinical trials still report results only about one sex, with consequent different rate of response and adverse reactions to treatment between men and women in clinical practice. This review reports the data found in the literature concerning the gender-related differences for the most representative hepatic diseases.

Steatosis induced CCL5 contributes to early-stage liver fibrosis in nonalcoholic fatty liver disease progress

The rapidly increasing prevalence of nonalcoholic fatty liver disease (NAFLD) has become one of the major public health threats in China and worldwide. However, during the development of NAFLD, the key mechanism underlying the progression of related fibrosis remains unclear, which greatly impedes the development of optimal NAFLD therapy. In the current study, we were endeavored to characterize a proinflammatory cytokine, CCL5, as a major contributor for fibrosis in NAFLD. The results showed that CCL5 was highly expressed in fatty liver and NASH patients. In NAFLD rats induced by 8-week-HFD, CCL5 and its receptor, CCR5, were significantly up-regulated and liver fibrosis exclusively occurred in this group. In addition, we showed that hepatocytes are the major source contributing to this CCL5 elevation. Interestingly, a CCL5 inhibitor Met-CCL5, significantly decreased liver fibrosis but not hepatic steatosis. Using a cell model of hepatic steatosis, we found that the conditioned medium of lipid-overloaded hepatocytes (Fa2N-4 cells) which produced excessive CCL5 stimulated the profibrotic activities of hepatic stellate cells (LX-2) as manifested by increased migration rate, proliferation and collagen production of LX-2 cells. CCL5 knockdown in Fa2N-4 cells, Met-CCL5 or CCR5 antibody treatment on LX-2 cells all significantly inhibited the conditioned medium of FFA-treated Fa2N-4 cells to exert stimulatory effects on LX-2 cells. Consistently, the conditioned medium of Fa2N-4 cells with CCL5 over-expression significantly enhanced migration rate, cell proliferation and collagen production of LX-2 cells. All these results support that CCL5 produced by steatotic hepatocytes plays an essential role in fibrotic signaling machinery of NAFLD. In addition, we were able to identify C/EBP-β as the up-stream regulator of CCL5 gene transcription in hepatocytes treated with free fatty acid (FFA). Our data strongly supported that CCL5 plays a pivotal regulatory role in hepatic fibrosis during NAFLD, which constitutes a novel and exciting observation that may call for potential future development of specific CCL5-targeted NAFLD therapy.

Prevalence and predictors of liver steatosis and fibrosis in unselected patients with HIV mono-infection

OBJECTIVES

Significant liver disease may develop in HIV mono-infected patients, usually associated with fatty liver and/or cART exposure. We estimated the prevalence and predictors of hepatic steatosis and fibrosis as assessed by ultrasound and transient elastography (TE).

METHODS

We enrolled 125 consecutive HIV mono-infected patients who underwent ultrasound and TE. Clinical, biochemical, immunological, virological features and medication history were analysed.

RESULTS

Mean age was 39.5±10.3years and 91% were male. Metabolic syndrome (MS) was present in 9.8%, diabetes in 5.6%, hypertension in 9.7%, dyslipidemia in 32.8%. Increased AST and ALT were found in 5.6% and 16.8% respectively. Eighty-five (68%) patients were on cART (median length of treatment of 3 years, IQR 0-17). Hepatic steatosis was detected in 61 (55%) patients and was independently associated with male sex (OR 14.6, 95% CI 1.44-148.17), age (OR 1.082, 95% CI 1.01-1.16), HOMA (OR 2.56, 95% CI 1.101-5.96) and GGT (OR 1.037, 95% CI 1.007-1.075). Significant fibrosis (stiffness>7.4kPa) was present in 22 patients (17.6%) and was significantly associated with MS (OR 3.99, 95% CI 1.001-16.09).

CONCLUSIONS

Liver fibrosis can develop in asymptomatic HIV mono-infected patients. This is likely associated with NAFLD and usually manifests with normal transaminases. Non-invasive screening for the presence of NAFLD and fibrosis should be considered in the routine care of such patients.

Medium-chain fatty acid reduces lipid accumulation by regulating expression of lipid-sensing genes in human liver cells with steatosis

Accumulation of lipids in the liver can lead to cell dysfunction and steatosis, an important factor in pathogenesis causing non-alcoholic fatty liver disease. The mechanisms related to lipid deposition in the liver, however, remain poorly understood. This study was aimed to investigate the effects of medium-chain fatty acid (MCFA) on the lipolysis and expression of lipid-sensing genes in human liver cells with steatosis. A cellular steatosis model, which is suitable to experimentally investigate the impact of fat accumulation in the liver, was established in human normal liver cells (LO2 cells) with a mixture of free fatty acids (oleate/palmitate, 2:1) at 200 μm for 24 h incubation. MCFA was found to down-regulate expression of liver X receptor-α, sterol regulatory element binding protein-1, acetyl-CoA carboxylase, fatty acid synthase, CD 36 and lipoprotein lipase in this cellular model, and have positive effects on adipose triglyceride lipase and hormone-sensitive lipase. These results suggest that MCFA may reduce lipid accumulation by regulating key lipid-sensing genes in human liver cells with steatosis.

Peripheral and Hepatic Vein Cytokine Levels in Correlation with Non-Alcoholic Fatty Liver Disease (NAFLD)-Related Metabolic, Histological, and Haemodynamic Features

BACKGROUND

Haemodynamic impairment, inflammatory mediators and glucose metabolism disturbances have been implicated in the pathogenesis of Non-Alcoholic Fatty Liver Disease (NAFLD).

AIM

To investigate the cytokine profile in NAFLD patients in peripheral (P) and hepatic venous (HV) blood and to compare with histology, haemodynamic and metabolic parameters.

METHODS

40 obese patients with an indication for a transjugular liver biopsy were enrolled. Besides an extended liver and metabolic work-up, interleukin (IL) 1B, IL4, IL6, IL10, IL23, tumour necrosis factor (TNF) α and interferon (INF) γ were measured in plasma obtained from P and HV blood by means of multiplex immunoassay. The T helper (Th)1/Th2, the macrophage M1/M2 and the IL10/IL17a ratios were calculated.

RESULTS

A decrease of the P-IL10/IL17-ratio and an increase of the P-M1/M2-ratio (p<0.05) were observed in NASH versus no-NASH patients. A P-M1/M2-ratio increase was detected also in patients with portal hypertension in comparison with patients without it (p<0.05). Moreover diabetic patients showed an increase of the P-Th1/Th2-ratio in comparison with non-diabetic ones (p<0.05). The P-M1/M2 ratio positively correlated with steatosis grade (r = 0.39, p = 0.02) and insulin (r = 0.47, p = 0.003). The HV-M1/M2 ratio positively correlated with fasting insulin and Hepatic Venous Pressure Gradient (r = 0.47, p = 0.003). IL6 correlated with the visceral fat amount (r = 0.36, p = 0.02). The P- and HV-IL10/IL17 ratios negatively correlated with fasting insulin (respectively r = -0.4, p = 0.005 and r = 0.4, p = 0.01).

CONCLUSIONS

A proinflammatory cytokine state is associated with more disturbed metabolic, histological, and haemodynamic features in NAFLD obese patients. An increase of the M1/M2 ratio and a decrease of the IL10/IL17 ratio play a key role in this process.

Trypanosoma cruzi infection is a potent risk factor for non-alcoholic steatohepatitis enhancing local and systemic inflammation associated with strong oxidative stress and metabolic disorders

BACKGROUND

The immune mechanisms underlying experimental non-alcoholic steatohepatitis (NASH), and more interestingly, the effect of T. cruzi chronic infection on the pathogenesis of this metabolic disorder are not completely understood.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated immunological parameters in male C57BL/6 wild type and TLR4 deficient mice fed with a standard, low fat diet, LFD (3% fat) as control group, or a medium fat diet, MFD (14% fat) in order to induce NASH, or mice infected intraperitoneally with 100 blood-derived trypomastigotes of Tulahuen strain and also fed with LFD (I+LFD) or MFD (I+MFD) for 24 weeks. We demonstrated that MFD by itself was able to induce NASH in WT mice and that parasitic infection induced marked metabolic changes with reduction of body weight and steatosis revealed by histological studies. The I+MFD group also improved insulin resistance, demonstrated by homeostasis model assessment of insulin resistance (HOMA-IR) analysis; although parasitic infection increased the triglycerides and cholesterol plasma levels. In addition, hepatic M1 inflammatory macrophages and cytotoxic T cells showed intracellular inflammatory cytokines which were associated with high levels of IL6, IFNγ and IL17 plasmatic cytokines and CCL2 chemokine. These findings correlated with an increase in hepatic parasite load in I+MFD group demonstrated by qPCR assays. The recruitment of hepatic B lymphocytes, NK and dendritic cells was enhanced by MFD, and it was intensified by parasitic infection. These results were TLR4 signaling dependent. Flow cytometry and confocal microscopy analysis demonstrated that the reactive oxygen species and peroxinitrites produced by liver inflammatory leukocytes of MFD group were also exacerbated by parasitic infection in our NASH model.

CONCLUSIONS

We highlight that a medium fat diet by itself is able to induce steatohepatitis. Our results also suggest a synergic effect between damage associated with molecular patterns generated during NASH and parasitic infection, revealing an intense cross-talk between metabolically active tissues, such as the liver, and the immune system. Thus, T. cruzi infection must be considered as an additional risk factor since exacerbates the inflammation and accelerates the development of hepatic injury.

Noninvasive Assessment of Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is prevalent in 20-25% of the general population and is associated with metabolic risk factors such as obesity, diabetes mellitus, and dyslipidemia. Histologically, NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. As NASH develops in only 10-15% of patients with NAFLD, it is not practical to biopsy all patients who present with NAFLD. Noninvasive fibrosis tests have been extensively developed recently and offer alternatives for staging fibrosis. Despite their increasing use, such tests cannot adequately differentiate simple steatosis from NASH. At present, such tests can be used as first line tests to rule out patients without advanced fibrosis and thus prevent unnecessary secondary care referrals in a significant number of patients. In this review we present the evidence for the use of noninvasive fibrosis tests in patients with NAFLD.

Focus on emerging drugs for the treatment of patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disorder in Western countries and is increasingly being recognized in developing nations. Fatty liver disease encompasses a spectrum of hepatic pathology, ranging from simple steatosis to non-alcoholic steatohepatitis, cirrhosis, hepatocellular carcinoma and end-stage liver disease. Moreover, NAFLD is often associated with other metabolic conditions, such as diabetes mellitus type 2, dyslipidemia and visceral obesity. The most recent guidelines suggest the management and treatment of patients with NAFLD considering both the liver disease and the associated metabolic co-morbidities. Diet and physical exercise are considered the first line of treatment for patients with NAFLD, but their results on therapeutic efficacy are often contrasting. Behavior therapy is necessary most of the time to achieve a sufficient result. Pharmacological therapy includes a wide variety of classes of molecules with different therapeutic targets and, often, little evidence supporting the real efficacy. Despite the abundance of clinical trials, NAFLD therapy remains a challenge for the scientific community, and there are no licensed therapies for NAFLD. Urgently, new pharmacological approaches are needed. Here, we will focus on the challenges facing actual therapeutic strategies and the most recent investigated molecules.

Future treatments of cirrhosis

Cirrhosis can be sub-classified in clinical stages with distinct differences in prognosis and can even be reversed in some cases with successful etiological treatment. In this article, we review potential future therapies of cirrhosis, mainly focusing in the expansion of indications of currently licensed drugs. We strongly advocate that future therapies should focus on preventing the advent of complications and further progression of liver disease and should involve both primary and secondary care physicians. Such strategies could be based on the combination of currently licensed, relatively safe and inexpensive drugs and such randomized controlled trials should be prioritized in patients with advanced liver disease. The paradigm should be similar to that of prevention in cardiovascular diseases and long-term follow-up trials are needed.

Risk of postprandial insulin resistance: the liver/vagus rapport

Ingestion of a meal is the greatest challenge faced by glucose homeostasis. The surge of nutrients has to be disposed quickly, as high concentrations in the bloodstream may have pathophysiological effects, and also properly, as misplaced reserves may induce problems in affected tissues. Thus, loss of the ability to adequately dispose of ingested nutrients can be expected to lead to glucose intolerance, and favor the development of pathologies. Achieving interplay of several organs is of upmost importance to maintain effectively postprandial glucose clearance, with the liver being responsible of orchestrating global glycemic control. This dogmatic role of the liver in postprandial insulin sensitivity is tightly associated with the vagus nerve. Herein, we uncover the behaviour of metabolic pathways determined by hepatic parasympathetic function status, in physiology and in pathophysiology. Likewise, the inquiry expands to address the impact of a modern lifestyle, especially one's feeding habits, on the hepatic parasympathetic nerve control of glucose metabolism.

Comparison of characteristics between nonobese and overweight/obese subjects with nonalcoholic fatty liver disease in a South Indian population

AIMS

This study was designed to compare the characteristics of nonobese and overweight/obese subjects with nonalcoholic fatty liver disease (NAFLD) in an urban South Indian population.

SUBJECTS AND METHODS

The study group comprises 541 subjects drawn from the Chennai Urban Rural Epidemiology Study (CURES), which was carried out on a representative sample of Chennai city in southern India. NAFLD was diagnosed by ultrasonography. Subjects with NAFLD were classified as nonobese (body mass index of ≤22.9 kg/m(2)) and overweight/obese (body mass index of ≥23 kg/m(2)) based on World Health Organization Asia Pacific guidelines. Coronary artery disease (CAD) was assessed by a resting 12-lead electrocardiogram that was Minnesota-coded. Insulin resistance was assessed by using the homeostasis assessment model (HOMA-IR) using the following formula: fasting insulin (μIU/mL)×fasting glucose (mmol/L)/22.5.

RESULTS

In total, 173 of 541 (32%) subjects had NAFLD, of whom 48 (27.7%) had nonobese NAFLD and 125 (72.3%) had overweight/obese NAFLD. Compared with overweight/obese NAFLD patients, fasting blood glucose (104±29 vs. 119±45 mg/dL; P<0.05) and HOMA-IR (2.1±1.8 vs. 2.9±1.8; P<0.001) were lower and high-density lipoprotein cholesterol (43±9 vs. 39±8 mg/dL; P<0.001) was higher among nonobese NAFLD subjects. Multiple logistic regression analysis showed a significant association between nonobese NAFLD and CAD (P=0.013) even after adjusting for age, diabetes, hypercholesterolemia, HOMA-IR, and hypertension.

CONCLUSIONS

This study suggests that even nonobese NAFLD subjects have an association with CAD.

Metabolic syndrome and insulin resistance: underlying causes and modification by exercise training

Metabolic syndrome (MS) is a collection of cardiometabolic risk factors that includes obesity, insulin resistance, hypertension, and dyslipidemia. Although there has been significant debate regarding the criteria and concept of the syndrome, this clustering of risk factors is unequivocally linked to an increased risk of developing type 2 diabetes and cardiovascular disease. Regardless of the true definition, based on current population estimates, nearly 100 million have MS. It is often characterized by insulin resistance, which some have suggested is a major underpinning link between physical inactivity and MS. The purpose of this review is to: (i) provide an overview of the history, causes and clinical aspects of MS, (ii) review the molecular mechanisms of insulin action and the causes of insulin resistance, and (iii) discuss the epidemiological and intervention data on the effects of exercise on MS and insulin sensitivity.

Immunological mechanisms in the pathophysiology of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is characterized by the presence of steatosis, inflammation and hepatocyte injury and constitutes hepatic manifestation of the metabolic syndrome. The pathogenesis of NASH is complex and implicates cross-talk between different metabolically active sites, such as liver and adipose tissue. Obesity is considered a chronic low-grade inflammatory state and the liver has been recognized as being an "immunological organ". The complex role of the immune system in the pathogenesis of NASH is currently raising great interest, also in view of the possible therapeutic potential of immunotherapy in NASH. This review focuses on the disturbances of the cells constituting the innate and adaptive immune system in the liver and in adipose tissue.

Independent associations of low 25 hydroxy vitamin D and high parathyroid hormonal levels with nonalcoholic fatty liver disease in Asian Indians residing in north India

OBJECTIVE

We analysed the associations of 25 hydroxy vitamin D [25(OH) D] and parathyroid hormone (PTH) levels with clinical, anthropometric, biochemical and body composition parameters in Asian Indians with nonalcoholic fatty liver disease (NAFLD).

METHODS

In this case-control study, 162 cases and 173 age and sex matched controls were recruited. Clinical, anthropometric, biochemical parameters and liver ultrasound were done. Percentage body fat (%BF), lean body mass and bone mineral density (BMD) were assessed by dual energy X-ray absorptiometry (DXA). Fasting insulin levels, value of homeostasis model assessment of insulin resistance (HOMA-IR), serum 25(OH) D, calcium and PTH levels were measured.

RESULTS

Subjects with NAFLD had lower serum 25(OH) D (19.4 ± 8.5 vs. 27.8 ± 9.4 ng/ml, p = 0.0001) and higher serum PTH (54.9 ± 19.5 vs.41.5 ± 18.3 pg/ml, p = 0.0001) levels as compared to controls. We observed significantly high values of systolic blood pressure (p = 0.002), waist circumference (p = 0.05), serum triglycerides (p = 0.002), total cholesterol (p = 0.002), alanine transaminase (p = 0.05), fasting insulin (p = 0.02) and HOMA-IR (p = 0.03) in the lowest 25(OH) D quartile. Multivariable-logistic regression showed that low serum 25(OH) D [OR (95%CI): 4.46 (2.58-7.72), p = 0.0001] and high PTH [OR (95%CI): 2.21 (1.50-3.30), p = 0.0001] level were independently associated with NAFLD.

CONCLUSION

Low serum 25(OH) D and high PTH levels were independently associated with the presence of NAFLD in Asian Indians residing in north India.

The severity of histologic liver lesions is independent of body mass index in patients with nonalcoholic fatty liver disease

GOALS/BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity, but it may also be present in lean individuals. We evaluated the characteristics of NAFLD patients, focusing on those with normal body mass index (BMI).

STUDY

One hundred and sixty-two of 185 consecutive NAFLD patients were included. Demographic, clinical, somatometric, and laboratory characteristics were recorded. BMI<25 kg/m2 was considered to be normal.

RESULTS

Of the 162 patients, 12% had normal BMI. Patients with normal compared with those with increased BMI fulfilled more frequently no criterion of metabolic syndrome (43% vs. 2%; P<0.001) and had higher median alanine aminotransferase (92 vs. 62 IU/L; P=0.032) and aspartate aminotransferase levels (45 vs. 37 IU/L; P=0.036). Liver stiffness values by transient elastography were significantly lower in patients with normal than in those with increased BMI (5.0 ± 1.6 vs. 9.5 ± 8.7 kPa; P=0.003). In the 56 patients with liver biopsy, the prevalence of nonalcoholic steatohepatitis (50% vs. 68.8%; P=0.423) and the severity of inflammation and fibrosis did not significantly differ between cases with normal and those with increased BMI.

CONCLUSIONS

Approximately 1 of 8 NAFLD patients coming to a Greek tertiary liver center has normal BMI. On liver biopsy, normal BMI patients often have nonalcoholic steatohepatitis and histologic liver lesions of similar severity to the overweight or obese patients.

Does PPARγ2 gene Pro12Ala polymorphism affect nonalcoholic fatty liver disease risk? Evidence from a meta-analysis

Genetic factors can substantially contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). A missense Pro12Ala substitution in the PPARγ2 gene (rs1801282) has been studied in relation with NAFLD risk in different ethnic groups, but findings have been inconclusive. The aim of this was to evaluate the association between rs1801282 and NAFLD through meta-analysis of all relevant published evidence. A systematic search to find eligible studies was performed in Medline, HuGE Navigator, and SCOPUS databases. The strength of association was evaluated using odds ratios with 95% confidence intervals obtained from a random effect approach and under additive, dominant, co-dominant, recessive, and allelic contrast models. Seven studies comprising 1474 cases and 2259 controls met the eligibility criteria and included in the meta-analysis. Combined results did not indicate any predisposing or protective effect for rs1801282 under any of the assessed modes of inheritance. The rate of heterogeneity was generally high due to the inter-study variations in terms of age, gender, and ethnicity. Evidence from the current meta-analysis indicated that rs1801282 variants are not associated with NAFLD risk. Future large-scale studies are required to substantiate the present findings.

Association of peroxisome proliferator activated receptor-γ gene with non-alcoholic fatty liver disease in Asian Indians residing in north India

BACKGROUND

Genetics of non-alcoholic fatty liver (NAFLD) in Asian Indians has been inadequately studied. We investigated the association of polymorphisms C161T and Pro12Ala of peroxisome proliferator-activated receptor gamma (PPARγ) with clinical and biochemical parameters in Asian Indians with NAFLD.

METHODS

In this case-control study, 162 NAFLD cases and 173 controls were recruited. Abdominal ultrasound, clinical and biochemical profiles, fasting insulin levels and value of homeostasis model assessment of insulin resistance were determined. Polymerase chain reaction-restriction fragment length polymorphisms of two polymorphisms were performed. The association of these polymorphisms with clinical and biochemical parameters was analysed.

RESULTS

Higher frequency of Ala and T alleles of PPARγ was obtained in cases. Ala/Ala genotype of PPARγ (Pro12Ala) was associated with significantly higher serum triglycerides (TG), alkaline phosphatase (ALK) and waist-hip ratio in cases as compared to controls. In C161T polymorphism, TT genotype was significantly increased TG (p=0.04), total cholesterol (p=0.01), ALK (p=0.04) and gamma-glutamyl transpeptidase (p=0.007) in cases. The linkage disequilibrium for these two single-nucleotide polymorphisms of PPARγ was differed in cases (D1=0.1; p=0.006) and controls (D1=0.07; p=0.1). Using a multivariate analysis after adjusting for age, sex and body mass index, the presence of NAFLD was linked to these two polymorphisms (odds ratio 1.64 (95% CI: 1.09-2.45, p=0.05)].

CONCLUSION

Asian Indians in north India carrying the alleles Ala and T of PPARγ (Pro12Ala and C161T) polymorphisms are predisposed to develop NAFLD.

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels in patients with nonalcoholic fatty liver disease

Background/Aims

Nonalcoholic fatty liver disease (NAFLD), one of the most common forms of chronic liver disease, is closely associated with obesity and insulin resistance (IR). Adipokines secreted by adipose tissue have recently been implicated in initiating and perpetuating the chronic inflammatory state observed in obesity and NAFLD. Recent studies suggest neutrophil gelatinase-associated lipocalin (NGAL) plays a key role in the pathogenesis of IR. The aims of this study were to determine urinary NGAL levels in patients with ultrasonography proven NAFLD and to correlate these levels with the metabolic profile and fibrosis grade in this population.

Methodology

Our cohort consisted of 65 consecutive patients undergoing abdominal ultrasonography for clinical suspicion of NAFLD. Patients were subsequently divided into two groups: no steatosis (n=20) and steatosis (n=45). The stage of fibrosis was measured using a four-point scale. Urinary NGAL was measured by a specific microparticle enzyme immunoassay. The degree of insulin resistance was determined by the homeostatic model assessment (HOMA). Glucose, insulin, lipid profile, and transaminases were also measured.

Results

Urinary NGAL levels correlated with body mass index, HOMA, fasting glucose, and insulin levels in patients with steatosis. Moreover, uNGAL levels were higher in patients with steatosis compared to those with no steatosis (49.8 ng/mL and 22.7 ng/mL, respectively) with a statistically significant difference (p<0.001). A stepwise increase in uNGAL levels from patients without fibrosis (21.7 ng/mL) to patients with cirrhosis (47.4 ng/mL) was noted (p<0.001).

Conclusions

Our study demonstrates that in adult patients with NAFLD, uNGAL levels correlate with BMI, insulin resistance, and lipid profiles, and identifies a novel association between uNGAL levels and hepatocellular injury in these patients.

Non-alcoholic fatty liver disease and metabolic syndrome in adolescents: pathogenetic role of genetic background and intrauterine environment

In the last three decades the incidence of metabolic syndrome (MetS) has been growing worldwide along with an increase of obesity, type 2 diabetes mellitus, and non-alcoholic fatty liver disease (NAFLD). In children and adolescents such epidemics are particularly worrisome, since the metabolic consequences in adulthood will significantly burden the health care system. Although the definition of MetS in childhood is still controversial, there is agreement with respect to NAFLD being the hepatic manifestation of MetS. However, the molecular pathogenesis of MetS and its contribution to NAFLD is complex and closely related to the pre- and postnatal environment as well as to genetic predisposing factors. The analysis of the possible relationships between NAFLD and MetS is particularly interesting, not only from an epidemiological point of view, but also to better understand the genetic and environmental factors contributing to the development of both diseases. We here summarize the most recent epidemiological data on the incidence of both diseases in adolescents, and several aspects linking MetS with NAFLD, discussing the possible role played by genetics and intrauterine environment.

Circulating vaspin and its relationship with insulin sensitivity, adiponectin, and liver histology in subjects with non-alcoholic steatohepatitis

OBJECTIVE

Non-alcoholic steatohepatitis (NASH) is closely associated with components of metabolic syndrome. Vaspin is a novel adipocytokine that may link obesity, insulin resistance (IR), and type 2 diabetes mellitus. We aimed to investigate circulating vaspin levels in subjects with NASH and also to search for the association of vaspin with IR, adiponectin, and histological findings.

MATERIAL AND METHODS

A total of 50 male patients with NASH and 30 healthy male controls were enrolled. Vaspin and adiponectin were measured with ELISA method. Insulin sensitivity determined by homeostasis model assessment (HOMA-IR) index.

RESULTS

Plasma vaspin levels were higher and adiponectin levels were lower in NASH group compared with controls (p < 0.01 and p < 0.001, respectively). However, in multivariate analysis adjusted for glucose and lipid parameters, and HOMA-IR indexes, the difference in vaspin concentrations was disappeared. Nonetheless, the difference regarding the adiponectin levels remained significant between groups (p = 0.03). Vaspin was negatively correlated with low-density lipoprotein cholesterol (r = -0.32, p = 0.03) in subjects with NASH.

CONCLUSIONS

This study indicates that circulating vaspin levels are not altered in male subjects with NASH. These results suggest that in the absence of metabolic risk factors, vaspin per se may not be involved in the pathogenesis of NASH.

Plasma adiponectin--an independent indicator of liver fat accumulation

Proinflammatory cytokines and adipokines have a significant role in the development and progression of fatty liver. The aim of our current study was to explore the major indicators for hepatic fat determined as liver brightness. In addition to peptide hormones, several known cardiovascular and metabolic risk factors were included in the model. This is a population-based, epidemiological, cross-sectional study where 1200 subjects (600 men and 600 women, aged 40-59 years) were randomly selected, half of them having hypertension and half of them being controls. The severity of liver adiposity was measured by ultrasound and based on the brightness of the liver estimated as a numerical value ranging from 0 to 2. With respect to the studied peptide hormones, the associations between liver brightness and plasma adiponectin (P < .001), leptin (P < .001), ghrelin (P = .005), and highly sensitive C-reactive protein concentrations (P < .001) were significant before adjustments. When several other risk factors (age, sex, body mass index, waist circumference, quantitative insulin sensitivity check index, smoking, and alcohol consumption) and novel risk markers (adiponectin, leptin, ghrelin, and highly sensitive C-reactive protein concentrations) were considered simultaneously, of the peptide hormones, adiponectin remained the strongest independent indicator of the brightness of the liver (P = .025). Adiponectin is a very strong predictor for liver brightness, even after adjustment for the numerous other metabolic risk factors, markers of inflammation, and novel obesity-related peptide hormones. Whether low adiponectin levels predict to liver fat accumulation remains to be explored in a future prospective follow-up of this cohort.

Is there any progress in the treatment of non-alcoholic fatty liver disease?

Despite the fact that non-alcoholic fatty liver disease (NAFLD) and its severe clinical form, non-alcoholic steatohepatitis, are becoming increasingly prevalent in the industrialised countries, there are no licensed pharmacological treatments for them. Weight loss and life modifications, antioxidant therapies and insulin-sensitising agents are the current treatment strategies and have all been tested with inconclusive results. Low sample numbers, inadequate treatment duration and invalid surrogate markers for treatment response might all account for these results. As NAFLD is a systemic rather than a liver disease, future trials should address the patient as a whole and also address cardiovascular risk factors.

Predictive value of the fibrosis scores in patients with chronic hepatitis C associated with liver fibrosis and metabolic syndrome

OBJECTIVE

We evaluated patients with chronic hepatitis C (CHC) and compared the clinical and pathological features of steatosis and metabolic syndrome to identify the risk factors for CHC with severe fibrosis.

METHODS

One hundred seventy-one patients with biopsy-confirmed CHC were included in the study: 90 males and 81 females, age 56.2 ± 12.8 years; 46 with obesity (BMI≥25 kg/m(2)); 51 with hypertension; 36 with type 2 diabetes mellitus; and 20 with hypertriglyceridemia.

RESULTS

Steatosis was detected in 79 patients (46%); 92 patients (54%) showed no steatosis. Seventy-four patients (43%) showed mild fibrosis and 97 patients (56%) showed severe fibrosis. The variables that were significantly associated with steatosis were obesity [odds ratio 2.160 (1.010-4.727), p=0.046] and type 2 diabetes [odds ratio 3.667 (1.559-8.430), p=0.027]. The variables that were significantly associated with severe fibrosis were older age [odds ratio 2.675 (1.309-5.464), p=0.007], obesity [odds ratio 2.156 (1.006-4.619), p=0.048] and type 2 diabetes [odds ratio 8.739 (2.845-26.846), p=0.0002]. Nagasaki (N) score (the total number of specific risk factors, namely an older age, obesity, and type 2 diabetes) was higher in the severe fibrosis group than in the mild fibrosis group (mild fibrosis: severe fibrosis=1.48 ± 1.14 vs.2.66 ± 94, p<0.001).

CONCLUSION

Metabolic syndrome factors, including obesity and diabetes, play a critical role in the pathogenesis of fibrosis in CHC. The N score was therefore found to be a significant predictor of severe fibrosis in CHC.

Progression of alcoholic and non-alcoholic steatohepatitis: common metabolic aspects of innate immune system and oxidative stress

Growing evidence indicates that the innate immune system and oxidative stress caused by gut-derived endotoxins play a key role in alcoholic liver disease (ALD). Intracellular mechanisms associated with endotoxin-induced signaling play a crucial role in the initiation and progression of ALD. It is now widely accepted that activation of the innate immune system and increased release of pro-inflammatory cytokines and other mediators play an important role in the development of ALD. Accumulating evidence suggests that alcohol-mediated upregulation of CYP2E1 expression may initiate lipid peroxidation via reactive oxygen species. Non-alcoholic steatohepatitis (NASH) is a liver disease characterized by histopathological features similar to those observed in ALD, but in the absence of significant alcohol consumption. Initial efforts to clarify the mechanisms that promote the progression from steatosis to steatohepatitis somewhat artificially divided disease mechanisms into "first and second hits." This model considered the development of steatosis to be the "first hit," increasing the sensitivity of the liver to the putative "second hit," leading to hepatocyte injury, inflammation, and oxidative stress. We have emphasized the important role of gut-derived bacterial toxins, the innate immune system, and oxidative stress in the common pathogenic mechanism in ALD and NASH progression.

Serum hepcidin levels are related to the severity of liver histological lesions in chronic hepatitis C

Hepcidin is synthesized in the liver and has a crucial role in iron homoeostasis. Its synthesis is up-regulated in chronic inflammation and iron excess. We examined the determinants of serum hepcidin and liver hepcidin mRNA levels and their association with histological lesions in patients with chronic hepatitis C (CHC) and healthy controls. We studied 96 patients with CHC and 30 controls. Serum hepcidin levels were measured by an in-house competitive ELISA. Hepcidin mRNA levels were determined by a one-step qRT-PCR in total RNA extracted from liver biopsy specimens of 27 patients with CHC and six disease controls. Histological lesions were evaluated according to Ishak's classification. Serum hepcidin was significantly lower in patients with CHC than healthy controls (14.6 ± 7.3 vs 34.6 ± 17.3 ng/mL, P < 0.001). In patients with CHC, serum hepcidin correlated positively with aspartate aminotransferase (r = 0.334, P = 0.001) and insulin resistance (r = 0.27, P = 0.016) and had a trend for correlation with alanine aminotransferase (r = 0.197, P = 0.057) and serum haemoglobin (r = 0.188, P = 0.067) but not with ferritin. A significant positive correlation was also found between serum hepcidin levels and both necroinflammation (r = 0.259, P = 0.011) and fibrosis (r = 0.214, P = 0.036). Serum hepcidin was among others an independent predictor of cirrhosis (odds ratio: 1.145, P = 0.039). Liver hepcidin mRNA levels did not differ between patients and controls and were relatively lower in patients with than without cirrhosis (19.3 ± 21.7 vs 38.3 ± 26.0, P = 0.067). Patients with CHC have reduced serum hepcidin levels, which correlate with worse necroinflammation and fibrosis. The previously mentioned observations suggest a viral effect on hepatic hepcidin production, but might also support its involvement in the inflammatory process.

Hepatic lipogranulomas in patients with chronic liver disease: Association with hepatitis C and fatty liver disease

AIM: To study the significance and clinical implication of hepatic lipogranuloma in chronic liver diseases, including fatty liver disease and hepatitis C.

METHODS: A total of 376 sequential, archival liver biopsy specimens were reviewed. Lipogranuloma, steatosis and steato-fibrosis were evaluated with combined hematoxylin and eosin and Masson’s trichrome staining.

RESULTS: Fifty-eight (15.4%) patients had lipogranuloma, including 46 patients with hepatitis C, 14 patients with fatty liver disease, and 5 patients with other diseases. Hepatic lipogranuloma was more frequently seen in patients with hepatitis C (21%) and fatty liver disease (18%), and its incidence was significantly higher than that in control group (P < 0.0002 and P < 0.007, respectively). In addition, 39 out of the 58 patients with lipogranuloma were associated with steatosis and/or steato-fibrosis. Of the 18 lipogranuloma patients with clinical information available for review, 15 (83%) had risk factors associated with fatty liver disease, such as alcohol use, obesity, hyperlipidemia, and diabetes mellitus. Although the incidence of these risk factors was greater in patients with lipogranuloma than in control group (60%), it did not reach statistical significance.

CONCLUSION: Hepatic lipogranuloma is not limited to mineral oil use and commonly associated with hepatic steatosis, hepatitis C and fatty liver disease. With additional histological features of steato-fibrosis, lipogranuloma can also be used as a marker of prior hepatic steatosis.

Individualisation of antiviral therapy for chronic hepatitis C

The combination of pegylated-interferon (PEG-IFN)/ribavirin is currently the standard of care antiviral treatment for chronic hepatitis C (CHC), but optimal results require an individual approach. Key issues are to deliver doses that confer optimal antiviral efficacy against hepatitis C virus (HCV) for a time sufficient to minimise relapse. Viral monitoring during therapy guides the subsequent treatment course, particularly HCV RNA results at 4 weeks (rapid viral response [RVR]) and 12 weeks (complete early viral response [cEVR]). There is strong evidence that for most patients with genotypes 2 or 3 HCV infection, RVR allows truncation of treatment to 16 weeks, provided ribavirin dose is weight-based. However, those patients with cirrhosis, insulin resistance/diabetes or older than 50 years need 6-12 months treatment. For "difficult-to-treat" CHC (genotypes 1 and 4), RVR is infrequent (approximately 15% in European studies), but allows treatment to be truncated from 48 to 24 weeks. Without RVR, there is some evidence that longer treatment (72 weeks) improves sustained viral response (SVR). However, "induction dosing" first 12 weeks of PEG-IFN clearly does not improve SVR. To prevent dose reductions and complete therapy, it is critical to detect and treat depression and other disabling side-effects, including judicious use of growth factors for severe anemia or neutropenia and possibly, thrombocytopenia. Another potentially important aspect may be attempts to counter central obesity and insulin resistance, which confer suboptimal antiviral response with any HCV genotype. Treatment partnerships with specialist nurses, psychological therapists and other healthcare workers are also essential for optimal individual management of patients with CHC.

Serum HCV RNA levels and HCV genotype do not affect insulin resistance in nondiabetic patients with chronic hepatitis C: a multicentre study

BACKGROUND

Chronic hepatitis C (CHC) induces insulin resistance (IR) and subsequently diabetes.

AIM

To examine viral, metabolic and histological predictors of IR in 275 CHC patients to test the hypothesis that IR differs among HCV genotypes and that viral replication directly affects IR.

METHODS

We studied 275 nondiabetic treatment-naïve CHC patients. Histological lesions were evaluated according to Ishak. IR was assessed using homeostasis model assessment for insulin resistance (HOMA-IR).

RESULTS

HOMA > 3.0 was found in 37% of patients, independently associated with higher BMI and GGT. In genotype non-3 patients, HOMA > 3.0 was associated with higher BMI and GGT values, while no significant association was noted in genotype 3 patients. In non-obese patients with minimal fibrosis, HOMA > 3.0 was found in 20% of cases without significant differences among genotypes. No association between HOMA > 3.0 and HCV-RNA levels was found. Severe fibrosis (stage 5-6) related to older age (OR:1.048), HOMA-IR (OR:1.177), necroinflammation (OR: 2.990) and higher ALT (OR: 1.009) and GGT (OR:1.006).

CONCLUSIONS

IR develops at early stages of CHC without significant differences among genotypes. It is more frequent in obese patients with steatosis and contributes to fibrosis progression. However, IR does not seem to be associated with viraemia and therefore its exact pathogenetic mechanism in CHC remains elusive.

Smoking is associated with steatosis and severe fibrosis in chronic hepatitis C but not B

OBJECTIVE

The results of retrospective studies suggest an association between smoking, insulin resistance, steatosis and fibrosis in patients with chronic hepatitis C (CHC); no data are available for chronic hepatitis B (CHB). The purpose of this study was to evaluate the relationship, if any, of such factors on liver fibrosis in a cohort of patients with CHB and CHC.

MATERIAL AND METHODS

The study prospectively included 271 consecutive patients with CHB (n=95) or CHC (n=176) who had undergone liver biopsies. Each patient completed a questionnaire on smoking habits; anthropometric measurements and laboratory examinations were carried out and histological lesions were recorded.

RESULTS

In CHC patients, severe fibrosis was independently associated with a higher body mass index (BMI) (OR: 1.180, 95% CI: 1.028-1.354; p=0.019), heavy smoking (OR: 3.923, 95% CI: 1.356-11.348; p=0.012), higher alanine aminotransferase (ALAT) levels (OR: 1.010, 95% CI: 1.003-1.017; p=0.005) and alkaline phosphatase (ALP) levels (OR: 1.016, 95% CI: 1.001-1.030; p=0.03) and presence of necroinflammation (OR: 11.165, 95% CI: 1.286-96.970; p=0.029). Moreover, steatosis was independently associated with high gamma-glutamyl transpeptidase (GGT) values, heavy smoking and presence of necroinflammation. In CHB patients, no association between smoking habits and fibrosis or steatosis was noted.

CONCLUSIONS

Heavy smoking is associated with severe fibrosis in CHC but not CHB. Heavy smoking is also significantly associated with steatosis in CHC and this could be the link between smoking and fibrosis progression.

Adipokines in nonalcoholic steatohepatitis: from pathogenesis to implications in diagnosis and therapy

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and can vary from benign steatosis to end-stage liver disease. The pathogenesis of non-alcoholic steatohepatitis (NASH) is currently thought to involve a multiple-hit process with the first hit being the accumulation of liver fat which is followed by the development of necroinflammation and fibrosis. There is mounting evidence that cytokines secreted from adipose tissue, namely, adipokines, are implicated in the pathogenesis and progression of NAFLD. In the current review, we explore the role of these adipokines, particularly leptin, adiponectin, resistin, tumor necrosis factor-a, and interleukin-6 in NASH, as elucidated in experimental models and clinical practice. We also comment on their potential use as noninvasive markers for differentiating simple fatty liver from NASH as well as on their potential future therapeutic role in patients with NASH.