Diabetes and liver disease: an ominous association

Diabetes mellitus and advanced liver disease are associated with each other more frequently than expected by chance, and such an association carries a significant risk of morbidity and mortality. A metabolic pathway leading to advanced liver disease via fatty liver and steatohepatitis has been demonstrated, further supporting the possibility that cirrhosis may be a late complication of diabetes. In addition, an interaction between hepatitis C virus (HCV) and insulin resistance increases the overall prevalence of associated diseases, through largely unidentified mechanisms. Extensive prospective monitoring of non-alcoholic fatty liver disease cases, analysis of insulin signaling in HCV-infected patients using molecular biology techniques, and intervention studies, will help to clarify the mechanisms of action of the possible clinical strategies, the predictive value of biochemical, histological, and clinical markers, and the effectiveness of treatments available.

Histological assessment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an important complication of the metabolic syndrome, which is becoming an increasingly common cause of chronic liver disease. Histological changes typically mainly affect perivenular regions of the liver parenchyma and include an overlapping spectrum of steatosis, steatohepatitis and persinusoidal or pericellular fibrosis, in some cases leading to cirrhosis. Once cirrhosis has developed, typical hepatocellular changes are often no longer conspicuous, leading to such cases being mistakenly diagnosed as 'cryptogenic'. Portal inflammation, ductular reaction and periportal fibrosis can also be seen as part of the morphological spectrum of NAFLD, particularly in the paediatric population. Hepatocellular carcinoma has also been described as a complication of NAFLD-associated cirrhosis. NAFLD is also an important cofactor in other chronic liver diseases, especially hepatitis C. Histological assessments have an important role to play in the diagnosis and management of NAFLD. These include making the potentially important distinction between simple steatosis and steatohepatitis and providing pointers to the aetiology, including cases where a dual pathology exists. A number of systems have been devised for grading and staging the severity of fatty liver disease. These require further evaluation, but have a potentially important role to play in determining prognosis and monitoring therapeutic responses.

Predictors of non-alcoholic fatty liver disease in obese children

OBJECTIVE

To evaluate predictors of non-alcoholic fatty liver disease (NAFLD) in obese children.

DESIGN

Cross-sectional study.

SUBJECTS

Two hundred and sixty-eight obese children not consuming alcohol and without hepatitis B or C were consecutively studied at an auxology clinic.

MEASUREMENTS

Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, glucose, glucose during oral glucose tolerance testing (OGTT), insulin, insulin during OGTT, insulin resistance as estimated by homeostasis model assessment (HOMA), C-reactive protein (CRP), and systolic and diastolic blood pressure were measured. Fatty liver was diagnosed by ultrasonography using standard criteria. Univariable and multivariable logistic regression was used to evaluate predictors of NAFLD. All predictors except gender and pubertal status were modeled as continuous variables.

RESULTS

NAFLD was detected in 44% of obese children. At univariable analysis, male gender, Z-score of body mass index (BMI) (Z-BMI), ALT, AST, GGT, triglycerides, uric acid, glucose, glucose during OGTT, insulin, insulin during OGTT, HOMA, CRP and systolic blood pressure were predictors of NAFLD, whereas HDL-cholesterol and late-pubertal status were predictors of the normal liver. At multivariable analysis, however, only Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT were independent predictors of NAFLD.

CONCLUSION

Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT are independent predictors of NAFLD in Italian obese children, with most of the prediction explained by ALT and Z-BMI.

Fibrosis in genotype 3 chronic hepatitis C and nonalcoholic fatty liver disease: Role of insulin resistance and hepatic steatosis

Hepatic steatosis has been associated with fibrosis, but it is unknown whether the latter is independent of the etiology of fat infiltration. We analyzed the relationship between clinical characteristics, insulin resistance (HOMA-R) and histological parameters in 132 patients with "viral" steatosis caused by genotype 3 chronic hepatitis C (CHC-3) and 132 patients with "metabolic" steatosis caused by nonalcoholic fatty liver disease (NAFLD), matched by age, BMI, and degree of liver fat accumulation. Tests of liver function were comparable in the two study populations. The prevalence of features of insulin resistance was higher in NAFLD, as was HOMA-R (P = .008). Logistic regression analysis confirmed that steatosis was associated with a high viral load and low serum cholesterol in CHC-3, and with high aminotransferase, glucose, ferritin and hypertriglyceridemia in NAFLD. At univariate analysis, advanced fibrosis was associated with steatosis in NAFLD, but not in CHC-3. Other parameters related to fibrosis severity were HOMA-R and a low platelet count in CHC-3, and high aminotransferases, HOMA-R, ferritin and low HDL-cholesterol in NAFLD. On multivariate analysis, only low platelet count (OR = 0.78; 95% CI, 0.67-0.92) and HOMA-R (OR = 2.98; 1.13-7.89) were independent predictors of advanced fibrosis in CHC-3. In NAFLD, severe fibrosis was predicted by fat grading (OR = 3.03; 1.41-6.53), ferritin (OR = 1.13; 1.03-1.25) and HOMA-R (OR = 1.16; 1.02-1.31). In conclusion, insulin resistance is an independent predictor of advanced fibrosis in both NAFLD and CHC-3, but the extent of steatosis contributes to advanced disease only in NAFLD. Virus-induced hepatic steatosis as seen in CHC-3 does not contribute significantly to liver fibrosis.

gamma-Glutamyltransferase as a predictor of chronic kidney disease in nonhypertensive and nondiabetic Korean men

BACKGROUND

Little research has been done to examine whether gamma-glutamyltransferase (GGT) is prospectively associated with the development of chronic kidney disease (CKD). We performed a prospective study to examine the association between GGT and the risk for the development of CKD.

METHODS

The study cohort included a total of 10 337 healthy males with normal baseline kidney functions and no proteinuria. Participants were workers in a semiconductor manufacturing company and its 13 affiliates. CKD was defined as either the presence of proteinuria or a glomerular filtration rate (GFR) of < 60 mL x min(-1) x (1.73(2))(-1). Cox proportional hazards models were used to calculate the adjusted hazard ratios in separate models for CKD.

RESULTS

During a follow-up period of 25,774.4 person-years, 366 men developed CKD. After adjustments were made for age, baseline GFR, triglyceride, and HDL-C, the risk for CKD increased with an increasing quartile of serum GGT (p for trend <0.001). The top one fourth of serum GGT vs the bottom one fourth of relative risks for CKD was 1.90 (95% confidence interval, 1.37-2.63). These associations were also apparent in participants who consumed < or = 20 g/day of alcohol and those with normal weight, with values of alanine aminotransferase within reference intervals, or with C-reactive protein < 3.0 mg/L, and participants without metabolic syndrome.

CONCLUSIONS

Our findings, which were obtained from a large work-site cohort and excluded individuals with diabetes and hypertension, indicated that serum GGT may be an early predictor for the development of CKD, independent of baseline confounding factors.

Nonalcoholic fatty liver disease and HIV infection

As persons with HIV live longer, chronic liver disease is increasingly important. Nonalcoholic fatty liver disease (NAFLD) is characterized by excess fat in hepatocytes in patients without significant alcohol use. It can progress from steatosis to nonalcoholic steatohepatitis (NASH) to cirrhosis. Visceral obesity and insulin resistance are integral to the pathogenesis of NAFLD. Patients with HIV are at greater risk of NAFLD due to antiretroviral therapy and viral hepatitis coinfection. Antiretroviral therapy can lead to patterns of injury that include steatosis and NASH. Coinfection with hepatitis C virus increases the risk of insulin resistance and hepatic steatosis, and co-existent features of NASH have also been reported. Histological-based, longitudinal studies are needed that address the interactions of NAFLD and HIV infection, the effects of antiretroviral therapy and hepatotropic virus coinfection, and inform better management strategies.

The changing epidemiology and natural history of hepatitis C virus infection

Injection drug use remains the predominant mode of transmission of hepatitis C virus (HCV) infection. Growing numbers of persons who have been chronically infected with HCV for 20 or more years are coming to medical attention and are at risk for serious complications of chronic infection, including cirrhosis and hepatocellular carcinoma. Factors linked with the development of advanced fibrosis and cirrhosis include age at infection, duration of infection, heavy alcohol use, coinfections with HIV or hepatitis B virus, and male sex. Emerging risk factors for disease progression include steatosis, insulin resistance (and factors associated with the metabolic syndrome), and host genetics.

Impact of liver steatosis on the antiviral response in the hepatitis C virus-associated chronic hepatitis

BACKGROUND/AIM

Liver steatosis (LS) has been variably associated with chronic hepatitis C (CHC) but whether it affects sustained virological response to antiviral treatment and by what mechanisms is a question still under debate, at least for some genotypes. The aim of this work was to assess the frequency of LS, its relationship with host and viral factors and to what extent it can influence the response to antiviral combination therapy with pegylated interferon (INF)+ribavirin in a group of patients with CHC from a single center.

PATIENTS

One hundred and twelve patients with histologically proven CHC were treated with Peg INF-alpha 2a 180 microg a week subcutaneously for 48 weeks plus ribavirin 1000 or 1200 mg/day, according to the patient's body weight. Steatosis was graded according to Brunt et al.

RESULTS

Forty-six out of 112 patients (41.1%) were sustained virological responders (SVR). Seventy-two out of 112 (64.3%) presented with LS at histology; in this group, there were 24 patients (33.3%) with SVR compared with 22 (55%) of the non-steatosis group (chi(2)=6.5, P<0.02). Variables associated with the steatosis group were: higher serum levels of AST (P<0.04), alanine aminotransferase (P<0.02), gamma-GT (P<0.004), genotype 3a (P<0.03) and severity of histology (staging P<0.05) but at multiple linear regression analysis only genotype 3a and staging were significantly associated with LS. In the SVR group, age and body mass index (BMI) were significantly lower (P<0001 and P<0.03, respectively) compared with non-responders; moreover, genotype 1 was more frequent in the NR group, while genotype 3 was more frequent in the SVR group. At histology, grading and staging were also lower in the SVR group. Multiple logistic regression showed that only the grade of steatosis and genotype 3a were the variables independently associated with SVR.

CONCLUSIONS

This study showed a frequency of LS on the higher side of the range so far reported in the literature and confirmed that it negatively influences response to therapy. Genotype1 was confirmed to be the most frequent type in our area. It is more frequent in patients with mild-moderate steatosis and seems to condition therapeutic response negatively, together with BMI and age. In contrast, genotype 3a is more frequent in patients with severe steatosis, but is a favorable predictor of successful therapy.

Hepatic steatosis and insulin resistance are associated with serum imbalance of adiponectin/tumour necrosis factor-alpha in chronic hepatitis C patients

BACKGROUND

Steatosis and insulin resistance (IR) have a pathogenic role in chronic hepatitis C (HCV). Adipocytokines balance modulates hepatic lipid content and IR.

AIM

To evaluate serum adipocytokines and relationship with virological, histological and metabolic parameters in chronic HCV.

METHODS

Adiponectin and tumour necrosis factor-alpha (TNF-alpha) levels, HCV genotypes, HCV-RNA, IR (HOMA-IR), body mass index and liver steatosis and fibrosis were assessed in 161 non-diabetic chronic HCV patients.

RESULTS

Chronic HCV patients with steatosis showed lower serum adiponectin levels and higher levels of TNF-alpha, HOMA, alanine aminotransferase, gamma-glutamiltransferase and Histological Activity Index (HAI) and fibrosis scores. Low adiponectin levels were independently associated with grades of steatosis and HOMA-IR. Higher tumour necrosis factor-alpha levels were observed in patients with low adiponectin levels. The extension of steatosis was inversely correlated with adiponectin levels. A correlation between grade of steatosis with HOMA-IR and fibrosis was observed. HCV genotype 3-infected patients showed lower adiponectin levels than those with other genotypes. An independent predictor of low adiponectin levels in genotype 3 infection was the extension of steatosis. Liver fibrosis score was associated with steatosis, HAI and age.

CONCLUSIONS

Chronic HCV patients with steatosis showed a serum adiponectin/TNF-alpha imbalance that is associated with IR. Reduced adiponectin levels may be involved in the pathogenesis of steatosis, which in turn accelerates progression of fibrosis in chronic HCV.

Elevated serum uric acid levels in metabolic syndrome: an active component or an innocent bystander?

Elevated serum uric acid (SUA) levels are commonly seen in patients with the metabolic syndrome (MetS). Several mechanisms, both direct and indirect, connect the increased SUA levels with the established diagnostic criteria of MetS. It is possible that the increased cardiovascular disease risk associated with the MetS is partially attributed to elevated circulating SUA concentration. Several drugs used in the treatment of MetS may alter SUA levels. Thus, lifestyle measures together with the judicious selection of drugs for the treatment of hypertension, dyslipidemia, and insulin resistance associated with MetS may result in a reduction of SUA levels and possibly cardiovascular disease risk. This review summarizes the pathophysiologic association between SUA and MetS and focuses on the prevention of hyperuricemia and its cardiovascular consequences.

Fatty liver, carotid disease and gallstones: A study of age-related associations

AIM: To evaluate carotid intima-media thickening (IMT) and plaques, gallstone disease (GD) and fatty liver (FL) as a function of age.

METHODS: In 449 subjects, FL and carotid disease were assessed ultrasonographically. In a subgroup of 65/449 patients with non-alcoholic fatty liver disease (NAFLD), carotid disease, GD and associated factors were determined.

RESULTS: FL of unspecified etiology was more common in younger and GD in older individuals. FL subjects had an increased prevalence of IMT and a decreased prevalence of plaques and manifested carotid disease earlier. Plaques were more common in subjects with GD. Age was an independent predictor of carotid disease outcome and FL was a protective factor for plaques. In NAFLD, there was an inverse correlation between body weight and age and the latter independently predicted carotid findings.

CONCLUSION: Cardiovascular risk in patients with FL and NAFLD needs to be assessed as a function of age and body weight.

Non-alcoholic steatohepatitis and metabolic syndrome

PURPOSE OF REVIEW

Non-alcoholic steatohepatitis is part of a disease spectrum, non-alcoholic fatty liver disease, ranging from simple steatosis to cirrhosis, which is the most frequent cause of abnormal liver tests. There is clinical and epidemiological evidence that non-alcoholic fatty liver disease is the hepatic manifestation of the metabolic syndrome, having in common insulin resistance.

RECENT FINDINGS

The interest in the metabolic syndrome concept has been questioned. Insulin resistance, oxidative stress, mitochondrial dysfunction, immune deregulation and adipokines seem to be crucial in the pathogenesis of non-alcoholic fatty liver disease. The main treatment continues to rely on lifestyle changes, including weight loss strategies. Bariatric surgery in morbidly obese patients and insulin-sensitizing agents seem to be beneficial.

SUMMARY

There is strong evidence of the association of non-alcoholic steatohepatitis with the features of the metabolic syndrome, with its increased cardiovascular risk. Population interventions in order to change lifestyles and diet patterns that constitute risk factors for both situations are urgently needed. There is, however, evidence that in the presence of other risk factors, insulin resistance may be less important. These secondary forms of non-alcoholic steatohepatitis must be recognized, as they are potentially treatable by withdrawing the steatogenic factor.

Lack of association between microsomal triglyceride transfer protein gene polymorphism and liver steatosis in HCV-infected patients

OBJECTIVES

It has been shown that the HCV-core protein reduces the activity of microsomal triglyceride transfer protein (MTP) and could lead to steatosis in HCV-infected patients. The aim of our study was to investigate the influence of a functional polymorphism in the promoter region of the MTP gene (493G/T) on the development of HCV-related steatosis.

METHODS

Eighty-six chronic hepatitis C patients were studied to assess: the effects of body mass index, age, HCV genotype, and 493G/T MTP polymorphism on steatosis.

RESULTS

Steatosis was observed in 39 patients (45.3%). The 493G/T MTP polymorphism were not related to the development of steatosis.

CONCLUSION

The functional G/T MTP polymorphism do not seem to play any role in the development of steatosis in chronic hepatitis C.

New insights in the pathogenesis of non-alcoholic fatty liver disease

PURPOSE OF REVIEW

The hallmark of non-alcoholic fatty liver disease is hepatic steatosis. This is mostly a benign condition, but for largely unknown reasons it progresses to liver fibrosis, cirrhosis, and ultimately hepatocellular carcinoma in about 10% of patients. In this review we discuss recent progress in the understanding of the etiology of non-alcoholic fatty liver disease.

RECENT FINDINGS

In the last few years many connections between carbohydrate and triglyceride homeostasis, as well as inflammation, have surfaced. These seemingly unrelated metabolic pathways are linked by the action of diverse nuclear receptors. Many intermediates in lipid metabolism were shown to be activating ligands of these receptors, explaining the dysregulation of intermediary metabolism and induction of insulin resistance by a lipid overload. In addition to invoking a derangement in nuclear receptor regulation, excessive hepatic lipid influx may have direct metabolic consequences, particularly on mitochondrial function.

SUMMARY

Non-alcoholic fatty liver disease is a multifactorial disease. Many aspects of the disease and the links to inflammation can be understood when the multiple functions of the regulating nuclear receptors are taken into account. Many of these nuclear receptors seem attractive targets to develop therapy for non-alcoholic fatty liver disease and the closely related metabolic syndrome.

Chronic hepatitis C virus infection: genotyping and its clinical role

Chronic hepatitis C virus (HCV) infection is a worldwide public health problem with a global prevalence of 2%. A high proportion of those infected are at risk of developing cirrhosis and hepatocellular carcinoma and modeling data predicts that the burden of disease could soon increase substantially. The liver disease associated with chronic infection has led investigators to look for correlates between viral properties and disease progression, severity of disease and the response to antiviral therapy. HCV has been classified into six genotypes but genotype does not appear to influence disease presentation or severity of disease. However, genotype has been identified as a major predictor of response to interferon-based antiviral therapy. Antiviral regimens have been optimized for infections with HCV genotypes 1-4, although treatment strategies for genotypes 5 and 6 have yet to be developed. The molecular basis for the differences in response of HCV genotypes has yet to be determined.

Relationship between steatosis, inflammation, and fibrosis in chronic hepatitis C: a meta-analysis of individual patient data

BACKGROUND & AIMS

Steatosis is a frequent histologic finding in chronic hepatitis C (CHC), but it is unclear whether steatosis is an independent predictor for liver fibrosis. We evaluated the association between steatosis and fibrosis and their common correlates in persons with CHC and in subgroup analyses according to hepatitis C virus (HCV) genotype and body mass index.

METHODS

We conducted a meta-analysis on individual data from 3068 patients with histologically confirmed CHC recruited from 10 clinical centers in Italy, Switzerland, France, Australia, and the United States.

RESULTS

Steatosis was present in 1561 patients (50.9%) and fibrosis in 2688 (87.6%). HCV genotype was 1 in 1694 cases (55.2%), 2 in 563 (18.4%), 3 in 669 (21.8%), and 4 in 142 (4.6%). By stepwise logistic regression, steatosis was associated independently with genotype 3, the presence of fibrosis, diabetes, hepatic inflammation, ongoing alcohol abuse, higher body mass index, and older age. Fibrosis was associated independently with inflammatory activity, steatosis, male sex, and older age, whereas HCV genotype 2 was associated with reduced fibrosis. In the subgroup analyses, the association between steatosis and fibrosis invariably was dependent on a simultaneous association between steatosis and hepatic inflammation.

CONCLUSIONS

In this large and geographically different group of CHC patients, steatosis is confirmed as significantly and independently associated with fibrosis in CHC. Hepatic inflammation may mediate fibrogenesis in patients with liver steatosis. Control of metabolic factors (such as overweight, via lifestyle adjustments) appears important in the management of CHC.

Diabetes mellitus in chronic hepatitis B and C: prevalence and potential association with the extent of liver fibrosis

Diabetes mellitus has been reported to have an increased prevalence and to be associated with more severe fibrosis in patients with chronic hepatitis C. We evaluated the prevalence of diabetes mellitus in patients with chronic hepatitis B or C as well as the possible association between presence of diabetes and extent of liver fibrosis. In total, 434 consecutive patients with histologically documented hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (n = 174) or chronic hepatitis C (n = 260) were studied. The relationships of diabetes and epidemiological, somatomorphic, laboratory and histological patient characteristics were evaluated. Liver histological lesions were blindly evaluated according to the Ishak's classification. Diabetes was present in 58 (13%) patients, without any difference between those with chronic hepatitis B (14%) or C (13%). Diabetes was observed significantly less frequently in patients with fibrosis score 0-2 (7.7%) than 3-4 (10.4%) than 5-6 (29.2%) (P < 0.001). The presence of diabetes was independently associated with higher gamma-glutamyl-transpeptidase (GGT) levels and more severe fibrosis or presence of cirrhosis (P < 0.001) as well as with presence of hepatic steatosis and increased serum triglycerides levels (P < 0.02). In the noncirrhotic patients, diabetes was significantly associated with older age and higher GGT levels, but not with the extent of fibrosis. In conclusion, diabetes mellitus is observed in more than 10% of patients with either HBeAg-negative chronic hepatitis B or chronic hepatitis C. The presence of diabetes is strongly associated with more severe liver fibrosis, but such an association may be related to the high prevalence of diabetes in patients with cirrhosis.

Mechanisms of liver injury. III. Oxidative stress in the pathogenesis of hepatitis C virus

Hepatitis C virus (HCV) is a major cause of viral hepatitis that can progress to hepatic fibrosis, steatosis, hepatocellular carcinoma, and liver failure. HCV infection is characterized by a systemic oxidative stress that is most likely caused by a combination of chronic inflammation, iron overload, liver damage, and proteins encoded by HCV. The increased generation of reactive oxygen and nitrogen species, together with the decreased antioxidant defense, promotes the development and progression of hepatic and extrahepatic complications of HCV infection. This review discusses the possible mechanisms of HCV-induced oxidative stress and its role in HCV pathogenesis.

Liver microsomal triglyceride transfer protein is involved in hepatitis C liver steatosis

BACKGROUND & AIMS

Hepatic steatosis is frequent in chronic hepatitis C. Several mechanisms might be implicated, including metabolic cofactors and direct viral effects on intracellular lipid pathways. In a transgenic mouse model, hepatitis C virus (HCV) was shown to inhibit microsomal triglyceride transfer protein (MTP) activity, which is essential for hepatic lipoprotein assembly and secretion. No data are available on liver MTP activity in HCV-infected patients. We therefore investigated liver MTP gene expression and its lipid transfer activity in untreated cases infected with the major HCV genotypes showing variable degrees of hepatic steatosis.

METHODS

MTP messenger RNA (mRNA) levels were measured by real-time polymerase chain reaction, and MTP activity was assessed by fluorescent assay in liver biopsy specimens of 58 HCV-positive patients. A set of metabolic and serum lipid markers was also measured at the time of liver biopsies.

RESULTS

MTP mRNA levels showed a statistically significant (P = .001) inverse correlation with the degree of steatosis, independently of the HCV genotype. MTP mRNA levels also had an inverse correlation with serum insulin (P = .0002), homeostasis model assessment-insulin resistance (HOMA-IR) (P = .005), and body mass index (P = .02) in patients with HCV-1 and HCV-2 and with serum HCV-RNA (P = .02) in HCV-3 patients. Liver MTP-specific activity was significantly reduced in HCV-3 patients compared with those with other HCV genotypes (P = .004) and correlated with reduced serum cholesterol, apo B, and low-density lipoproteins.

CONCLUSIONS

MTP may play a central role in HCV-related steatosis, being modulated by different genotype-specific mechanisms, mainly hyperinsulinemia in non-HCV-3 patients, and more profound and direct virus-related effects in HCV-3-infected individuals.

The effect of the metabolic syndrome, hepatic steatosis and steatohepatitis on liver fibrosis in hereditary hemochromatosis

OBJECTIVES

The variability in phenotypic expression of hereditary hemochromatosis (HH) is not fully understood. We sought to examine whether the metabolic syndrome, hepatic steatosis or steatohepatitis influenced hepatic fibrosis among patients with HH and iron overload.

METHODS

We identified 86 patients with C282Y/C282Y or C282Y/H63D HH and iron overload (hepatic iron concentration (HIC) >2,200 microg/g for males, >1,600 microg/g for females). Features of the metabolic syndrome were assessed at the time of liver biopsy. Biopsies were scored by a blinded pathologist. Significant fibrosis was defined as peri-portal fibrosis or greater.

RESULTS

The mean (+/-SD) age of the study population was 53+/-12 years and 68 (79%) were male. The median (range) values of ferritin and HIC were 1,125 (253-9,530) microg/l and 9963 (1926-50 887) microg/g, respectively. The metabolic syndrome was present in 23 (27%), hepatic steatosis in 43 (50%), steatohepatitis in 18 (21%) and significant fibrosis in 38 (44%). Overall, neither the metabolic syndrome nor any of its components were associated with significant fibrosis or a higher mean fibrosis stage. Hepatic steatosis but not steatohepatitis was associated with a lower fibrosis stage. C282Y/H63D compound heterozygous individuals who had glucose intolerance had more severe fibrosis compared with those without glucose intolerance (1.0+/-1.0 vs. 0.1+/-0.3, P=0.01).

CONCLUSIONS

Overall, the metabolic syndrome and fatty liver were not associated with hepatic fibrosis among individuals with HH and iron overload. However, glucose intolerance may be important risk factor for the development of hepatic fibrosis in subjects with the C282Y/H63D HFE genotype.

Nonalcoholic fatty liver disease and liver transplantation

Nonalcoholic fatty liver disease affects a substantial proportion of the general population worldwide. This high prevalence of nonalcoholic fatty liver disease has important consequences in the donor selection process for liver transplantation, and in the posttransplant period given the high recurrence rate of disease. This paper reviews the prevalence of nonalcoholic fatty liver disease, its progressive potential, and the implications of this liver condition in both the pre- and post-liver transplantation setting.

Viral and metabolic factors influencing alanine aminotransferase activity in patients with chronic hepatitis C

BACKGROUND/AIMS

In chronic hepatitis C, disease progression and clinical manifestations are heterogenous. To clarify the role and interactions of viral and host factors in inducing liver cell injury, we examined the associations of several virological and metabolic variables with serum alanine aminotransferase levels.

METHODS

Patients with chronic hepatitis C enrolled in three phase III clinical trials of peginterferon alfa-2a (40KD) plus ribavirin (two studies analysing 'elevated' and one persistently 'normal' alanine aminotransferase) were included.

RESULTS

Multivariate analyses of 2,881 patients before treatment and of 1,403 patients with a sustained virological response indicated that gender, viral factors (genotype, HCV RNA titer) and indicators of metabolic syndrome (body mass index, blood pressure, blood glucose, cholesterol and triglyceride concentration) were associated with alanine aminotransferase levels. In addition, hepatitis C virus infection influenced serum lipids concentration according to a genotype-specific effect.

CONCLUSIONS

Heterogeneity in alanine aminotransferase levels in patients with chronic hepatitis C partially depends on the degree of derangement of fat and carbohydrate metabolism. As this is the result of an interaction of chronic hepatitis C infection with the patient's individual characteristics, treatment decisions should not be based on alanine aminotransferase level alone but rather on global evaluation of the patient.

Inflammation and conjugated linoleic acid: mechanisms of action and implications for human health

Data from a number of studies and trials have shown that different conjugated linoleic acids (CLA's) may produce beneficial effects on cancer, atherosclerosis, hypertension, diabetes and changes in body composition. Despite the increasing knowledge about CLA's implications on health, the mechanism of action of these fatty acids is not completely understood. Moreover, human studies indicate that some of these beneficial effects are considerably less evident than anticipated from mice studies, while the efficacy and safety of dietary supplements containing CLA have been questioned in some intervention trials. Recently, it has been suggested that the anti-carcinogenic and anti-atherosclerosis effects of CLA's stem from its anti-inflammatory properties. Because inflammatory responses are associated with the pathophysiology of many diseases, including obesity and the metabolic syndrome, the investigation in this area is of growing interest in recent years.

Prevalence of liver steatosis in patients with chronic hepatitis B: a study of associated factors and of relationship with fibrosis

OBJECTIVES

The clinical significance of hepatic steatosis in chronic hepatitis B virus patients is poorly understood. The purpose of this study was to determine risk factors for liver steatosis in chronic hepatitis B patients and its relationship with fibrosis.

METHODS

We retrospectively evaluated liver biopsies from patients with chronic hepatitis B treated in our department. Patients co-infected with other viruses (hepatitis C virus, HIV) or suffering from liver disease of any other cause were excluded from the study, as well as patients consuming alcohol above 30 g/day for males or 20 g/day for females. Liver steatosis, necroinflammation and fibrosis were assessed.

RESULTS

A total of 233 patients with chronic hepatitis B were included in the study. The mean age was 44.7+/-16.2 years. There were 164 men (70.4%) and 69 women (29.6%). The majority of patients were HbeAg-negative, 196/233 (84.1%). Thirty-seven patients had cirrhosis (15.9%). Steatosis was present in 42 patients (18%). Steatosis was independently associated with fasting glucose level (P=0.019) and being overweight (body mass index >or=25; P=0.021). No correlation was found with stage of fibrosis, grade of inflammation, alcohol use or other parameters. Ninety-four out of 233 patients (40.3%) had advanced fibrosis. Patients with advanced fibrosis were older than those with minimal or no fibrosis (47.6+/-17 versus 42.3+/-15.2 years, P=0.024) and more frequently had a higher grade of necroinflammation activity (57/94 (60.6%) versus 26/139 (18.7%), P<0.0001). There was no significant association between advanced fibrosis and the presence of steatosis or mild alcohol consumption.

CONCLUSION

Hepatic steatosis is present in 18% of our patients with biopsy-proven chronic hepatitis B. Steatosis is independently associated only with body mass index and fasting glucose level, risk factors for metabolic steatohepatitis, and was not correlated with the degree of fibrosis.

Hepatitis C infection and diabetes

Since the discovery of the hepatitis C virus (HCV) in 1989, attention has been paid to the association of chronic HCV infection and the development of diabetes. The risk factors for diabetes include older age, HCV genotype 3, severe liver fibrosis, family history of diabetes, and liver/kidney transplantation. Emerging evidence in animals and humans has shown that HCV infection induces hepatic steatosis and increases tumor necrosis factor-alpha level, both resulting in the development of insulin resistance and subsequent type 2 diabetes. It is suggested that the presence of diabetes and hepatic steatosis may enhance fibrosis progression, hepatocellular carcinoma, and atherosclerosis. Interferon is reportedly associated with improved glucose tolerance. However, interferon might enhance underlying autoimmunity against beta cells, leading to overt type 1 diabetes that is genetically predisposed or give rise to hyperglycemia, resulting in the development of type 2 diabetes. In light of the national epidemic of type 2 diabetes, the link between HCV and diabetes would be a major public health problem. Further clinical researches are awaited in order to effectively detect, prevent, and treat HCV-associated type 2 diabetes, which would also slow the progression of hepatitis C itself.

The medical complications of alcohol use: understanding mechanisms to improve management

The use of alcohol in a dependent or even a regular heavy pattern predisposes the drinker to a range of adverse consequences. These include a risk of direct harm from alcohol, including organ damage, mental health disorders and a range of social and legal problems associated with behaviours due to alcohol's effects. The range of organ damage associated with regular heavy alcohol consumption is well described. Much new information on the mechanisms by which damage occurs is available and is reviewed in this paper. New knowledge can assist in the development of more appropriate management strategies for those affected by the medical complications of alcohol use. Genetic susceptibility to tissue injury is explored and the reasons why many heavy drinkers do not appear to experience organ damage are considered. Approaches to the management of certain alcohol-related disorders are outlined.

Hepatitis C -- identifying patients with progressive liver injury

Hepatitis C follows a variable course with some patients developing progressive liver fibrosis, cirrhosis and hepatocellular carcinoma, while others have minimal or no significant liver disease after decades of infection. Studies have identified both host and viral factors associated with disease progression. The importance of general factors such as age at infection, gender, immune status and alcohol consumption has long been recognized; however recently, polymorphisms in a wide array of genes have also been shown to be associated with progressive fibrosis. How specific viral proteins may contribute to disease progression has also been studied. This review highlights what is currently known about the factors associated with progressive liver injury in patients with hepatitis C. A greater understanding of the determinants of disease progression will hopefully lead to improved utilization of existing treatments and ultimately may aid in identification of new therapeutic targets.

Hepatitis C and steatosis: a reappraisal

The overall prevalence of steatosis in patients with Hepatitis C virus (HCV) chronic infection is 55.5% (range 34.8-81.2%). This is a two to threefold increase compared with the prevalence of steatosis in chronic hepatitides because of other aetiologies and of the figures expected on the grounds of a steatosis-HCV chance association. HCV genotype 3 (HCV-3) has specific epidemiological features; furthermore, as compared with HCV-non-3 genotypes, it is associated with a higher prevalence (74.1%vs 47.9%, P < 0.01) and with more severe grades of steatosis (prevalence of grade 3 steatosis 29.6 vs 5.5 P < 0.01). Host and viral factors play a role, although to a variable extent, in the pathogenesis of HCV-3 and non-3 steatosis. HCV load and body mass index are associated with steatosis in HCV-3 and in HCV-non-3 patients respectively. Serum cholesterol levels and liver steatosis at baseline follow an inverse relationship in HCV infection. As hypocholesterolaemia corrects only in those sustained responders to antiviral treatment both in genotype 3 and in non-3 genotypes, the occurrence of a virally induced, acquired and reversible hypobetalipoproteinaemia seems plausible. Steatosis affects the natural course of HCV infection: it is associated with fibrosis, a possible mediator of increased risk to develop type 2 diabetes, it impairs the response to antiviral treatment in HCV-3 patients and might constitute a risk factor for the development of hepatocellular carcinoma. These observations indicate the need to evaluate the efficacy of combined antiviral and 'metabolic' approaches vs standard antiviral regimes in patients with steatosis and HCV chronic infection.

Elevated serum levels of alanine aminotransferase and gamma glutamyltransferase are markers of inflammation and oxidative stress independent of the metabolic syndrome

The present study attempted to establish whether elevated serum levels of alanine aminotransferase (ALT) and gamma glutamyltransferase (GGT) are independent (of each other) markers of systemic inflammation and oxidative stress as assessed by the plasma levels of C-reactive protein (CRP) and lipid peroxides (lipOX), regardless of the presence of underlying metabolic syndrome (as defined by the modified Adult Treatment Panel III (ATPIII) criteria). The plasma levels of CRP and lipOX were determined in 1483 middle-age Japanese men (42+/-9 years). A general linear model analysis indicated that elevated serum ALT and/or serum GGT (levels in the respective highest quartiles) were significantly related to the logarithms of the plasma levels of CRP (Beta=0.08 (0.05-0.11) and 0.08 (0.05-0.11), respectively) and the logarithm of the plasma levels of lipOX (Beta=0.03 (0.01-0.05) and 0.03 (0.01-0.05), respectively), regardless of the presence of underlying metabolic syndrome (MetS) (p<0.01). In addition, the presence of MetS and elevated serum levels of both of these liver enzymes additively increased the plasma levels of CRP and lipOX. Thus, it is proposed that elevated serum ALT and elevated serum GGT are independent markers of the activation of systemic inflammation and increased oxidative stress, independent of their relationship to MetS, and that the presence of MetS and elevations of both of these liver enzymes may additively worsen the atherogenic state.

Drug interactions between psychoactive substances and antiretroviral therapy in individuals infected with human immunodeficiency and hepatitis viruses

The liver disease characteristic of alcohol dependence encompasses three main related entities: steatosis, alcoholic hepatitis, and cirrhosis. Alcoholic cirrhosis is a leading cause of global morbidity and mortality. Alcohol intake among injecting drug users is a major contributor to transmission of viral infections, such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C viruses (HCV). HIV and HCV coinfected patients develop liver diseases earlier and more severely than the monoinfected individuals, including hepatocellular carcinoma. Interactions exist between the therapeutic drugs used to minimize and control the drug and alcohol dependence. Furthermore, drug-drug interactions occur between the highly active antiretroviral therapy (HAART) and alcohol, different HAART components and methadone, or each one of the therapies with the other, thus contributing to a higher toxicity level. With the evolution of effective antiretroviral therapy, survival of persons with HIV, and the syndrome it causes, acquired immunodeficiency syndrome (AIDS) has increased dramatically. Drug-drug interactions may appear between alcohol and anti-HBV or anti-HCV, therapy in the presence or absence of anti-HIV therapy. Several other medical-, social-, and drug-related factors of this population have to be considered when providing HAART. Because many coinfected patients also have problems with substance use, dealing with their drug dependence is an important first step in an attempt to improve adherence to and tolerance of antiviral therapy. It is necessary to minimize the risk of liver disease acceleration and/or reinfection with hepatitis viruses. Knowledge of potential drug interactions between methadone, antiretroviral therapy, psychoactive drugs, and antipsychotics and the role of coinfection with HBV or HCV and the drugs used in eradicating viral hepatitis permits suitable antiretroviral combinations.

Hepatic steatosis and insulin resistance: does etiology make a difference?

BACKGROUND/AIMS

To ascertain whether the etiology of hepatic steatosis modulates insulin resistance (IR) and to determine the predictors of IR.

METHODS

We studied IR through HOMA IR in 146 subjects, 99 of whom had ultrasonographic and/or histologic steatosis. Twenty-two had familial heterozygous hypobetalipoproteinemia (FHBL), 48 had non-alcoholic fatty liver disease (NAFLD), 34 HCV infection (17 with HCV1b, 17 with HCV3a) and 42 were healthy controls without steatosis.

RESULTS

Steatosis was present in 77.3% of FHBL and, by enrolment criteria, in all NAFLD and HCV cases. Overall HOMA-IR correlated with BMI and GGT (P<0.01). FHBL and healthy groups had similar HOMA-IR and GGT values, whereas higher levels were observed in HCV and NAFLD. HCV3a and FHBL patients were hypolipidemic. HOMA-IR was similar in FHBL patients and controls and lower than in HCV and NAFLD. FHBL patients had a high extent of steatosis, similar to that observed in HCV3a, but lower grading and staging than NAFLD and HCV. At multivariate analysis, steatosis and GGT predicted HOMA-IR.

CONCLUSIONS

Data suggest that not all hepatic fat associates with IR. FHBL patients, for some aspects, resemble HCV3a infection, possibly suggesting a shared steatogenic mechanism. Among steatotic patients serum GGT levels is the independent predictor of IR.

Liver disease in patients with diabetes mellitus

Diabetes mellitus is a growing health concern in our society. In addition to the well-known cardiovascular, renal, and ophthalmologic complications of diabetes, liver-related complications occur commonly and are often underrecognized. The ensuing article will review the relationship between diabetes mellitus and two common liver diseases: chronic hepatitis C and nonalcoholic fatty liver disease. The association with diabetes and cirrhosis, acute liver failure, hepatocellular carcinoma, and outcomes following orthotopic liver transplantation will also be discussed.

Hepatitis C virus (HCV) infection and hepatic steatosis

There are two discrete forms of steatosis that may be found in patients infected with hepatitis C virus (HCV). Metabolic steatosis can coexist with HCV, regardless of genotype, in patients with risk factors such as obesity, hyperlipidemia, and insulin resistance. The second form of hepatic steatosis in HCV patients is a result of the direct cytopathic effect of genotype 3 viral infections. There have been proposed mechanisms for this process but it remains elusive. Both categories of steatosis tend to hasten the progression of liver fibrosis and therefore prompt recognition and management should be initiated in patients with HCV and steatosis. The authors review the current understanding of the relationship between hepatitis C infection and hepatic steatosis and discuss future research directions.

Insulin resistance is associated with steatosis in nondiabetic patients with genotype 1 chronic hepatitis C

Conflicting data exist regarding the relationship between hepatitis C virus genotype 1 and hepatic steatosis as well as the latter's role in the progression of fibrosis and treatment response. We assessed factors associated with hepatic steatosis in genotype 1 chronic hepatitis C and the impact of hepatic fat on fibrosis development and interferon responsiveness. Two hundred ninety-one non-diabetic patients with genotype 1 chronic hepatitis C were examined for the presence of steatosis and its correlation with clinical, virological, and biochemical data, including insulin resistance (IR), evaluated by the homeostasis model assessment (HOMA) score. Steatosis was graded as mild (1%-20% of hepatocytes involved), moderate (21%-40% of hepatocytes involved), and severe (>40% of hepatocytes involved). Steatosis was mild in 110 of 291 (37.8%) and moderate/severe in 55 of 291 (18.9%) subjects. By logistic regression, moderate/severe steatosis was independently associated with the female sex (odds ratio [OR] 2.74; 95% CI 1.40-5.35), high gamma-glutamyltransferase levels (OR 1.52; 95% CI 1.22-1.91), and HOMA-score (OR 1.076; 95% CI 1.001-1.26). By logistic regression, moderate/severe steatosis (OR 2.78; 95% CI 1.21-6.4), and platelet counts (OR 0.97; 95% CI 0.96-0.98) were independent predictors of advanced fibrosis. Patients with moderate/severe steatosis had an OR of 0.52 (95% CI 0.30-0.90) for sustained virological response compared with patients with mild/absent steatosis. In conclusion, in nondiabetic European patients with genotype 1 hepatitis C at low risk for the metabolic syndrome, the prevalence of steatosis was nearly 60%. IR is a risk factor for moderate/severe steatosis, especially in men. Moderate/severe steatosis has clinical relevance, being associated with advanced fibrosis and hyporesponsiveness to antiviral therapy.

Hepatic steatosis in chronic hepatitis C: impact on response to anti-viral treatment with peg-interferon and ribavirin

BACKGROUND

There is increasing evidence that hepatic steatosis contributes to the progression of liver fibrosis, whereas its impact on the efficacy of anti-viral treatment is still under investigation.

AIM

To evaluate the effect of steatosis on the outcome of combined anti-viral treatment.

METHODS

We studied 102 consecutive naive patients with chronic hepatitis C receiving combined anti-viral therapy (peg-interferon alpha-2b and ribavirin).

RESULTS

Fifty (49%) of 102 patients had evidence of hepatic steatosis (29 grade 1, 16 grade 2 and 5 grade 3). Sustained virological response was similar in patients with and without steatosis (58% vs. 56%); moreover, the grade of steatosis did not affect the rate of sustained virological response (grade 1: 58%, grade 2: 56% and grade 3: 60%). Patients with steatosis had significantly higher serum levels of aspartate transaminase, alanine transaminase and gamma-glutamyltransferase (P = 0.007, 0.004 and 0.03, respectively), higher histological activity (P = 0.03), more advanced stage of fibrosis (P = 0.0394) and more often hepatitis C virus genotype 3 (P = 0.04).

CONCLUSIONS

Our findings suggest that hepatic steatosis in chronic hepatitis C, irrespective of its grade, is not a negative prognostic factor of response to combined anti-viral therapy, even when the histological and biochemical profile of the disease is more aggressive.

Hepatitis C virus infection can present with metabolic disease by inducing insulin resistance

Although hepatitis C virus (HCV) targets the liver, it has become increasingly evident that HCV can induce diseases of many organs. Recently, much attention is drawn to metabolic disorders in HCV infection. First, hepatic steatosis and derangement in lipid metabolism have been found characteristic of HCV infection, and later on, a correlation was noted between HCV infection and diabetes as well as insulin resistance. We have demonstrated that HCV by itself can induce insulin resistance through disturbing the insulin signaling pathway by HCV proteins. The fact that HCV infection induces insulin resistance by the virus itself may influence the progression of chronic liver disease and open up novel therapeutic approaches. In conclusion, towards the future, HCV infection needs to be viewed not only as a liver disease but also as a metabolic disease.

Nonalcoholic steatohepatitis: pathologic features and differential diagnosis

The worldwide epidemic of obesity has raised the awareness of nonalcoholic fatty liver disease (NAFLD) from that of a curiosity to one of a potentially progressive liver disease with risk for cirrhosis and hepatocellular carcinoma. This overview is focused on the histopathology of the spectrum of fatty liver disease, and discusses the role of liver biopsy, differential diagnoses, and new techniques in development. When pertinent, pathophysiology of this metabolic liver disease and recent treatment considerations have been mentioned as well.

Peroxisome Proliferator-Activated Receptor α L162V Polymorphism in Nonalcoholic Steatohepatitis and Genotype 1 Hepatitis C Virus-Related Liver Steatosis

BACKGROUND

Peroxisome proliferator-activated receptor alpha (PPARalpha) plays important roles in lipid metabolism. A recently discovered L162V polymorphism of the PPARalpha gene is associated with enhanced transcriptional activity. In this study, the frequency of L162V was investigated in nonalcoholic steatohepatitis (NASH) and genotype 1 hepatitis C virus (HCV)-related liver steatosis.

METHODS

Seventy-two NASH and 141 HCV-infected patients (54 with steatosis, 87 without steatosis) and 119 healthy controls were included. L162V polymorphism of the PPARalpha gene was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

RESULTS

PCR and RFLP analysis of the related gene segment was successful in 93%, 96%, and 100% of NASH and HCV-infected patients and controls, respectively. The frequency of the L162V polymorphism was similar in the NASH and HCV-infected patients and controls (5.9%, 3.6%, and 2.5%, respectively). No difference in the frequency of this polymorphism was observed in HCV-infected patients with or without significant liver steatosis. L162V was not associated with obesity, type 2 diabetes mellitus, hypercholesterolemia, or hypertriglyceridemia.

CONCLUSIONS

Neither NASH nor genotype 1 HCV-related liver steatosis seems to be associated with the PPARalpha L162V polymorphism. This polymorphism may have no association with the presence of type 2 diabetes mellitus, obesity, or various blood lipid alterations in NASH and HCV-infected patients.

Review article: hepatitis C virus-associated steatosis--pathogenic mechanisms and clinical implications

Steatosis is a common feature of chronic hepatitis C, and may be caused directly by the virus, as in genotype 3 infection, or be associated with host metabolic factors. The interaction of hepatitis C virus core protein with the lipoprotein secretion pathways causes the characteristic alterations of lipid metabolism observed in hepatitis C virus-related steatosis. Several pathogenic mechanisms are likely involved into the pathogenesis of hepatitis C virus-related steatosis, including hyper-homocysteinaemia, hypoadiponectinaemia and insulin resistance. Steatosis is a major determinant of the liver damage progression in chronic hepatitis C (CHC), and negatively affects the response rate to the interferon (IFN)-based anti-viral treatment. Moreover, recent evidence suggests that steatosis may contribute to liver carcinogenesis. Chronic hepatitis C is a recognized risk factor for type 2 diabetes and it could be implicated into the pathogenesis of atherosclerosis. The role of hepatitis C virus (HCV)-related steatosis in these epidemiological associations remains to be determined.

Review article: hepatic steatosis and insulin resistance

Hepatic steatosis may be both an adaptive phenomenon and an example of lipotoxicity. Its prevalence ranks in the same order of magnitude of insulin resistance in the general population. Studies support the finding that hepatic steatosis is secondary to insulin resistance and not vice versa. A steatotic liver will further contribute to the development of insulin resistance through impaired clearance of insulin from the portal blood, creating a vicious cycle. Insulin resistance is the leading force in the pathogenesis and natural history of non-alcoholic fatty liver disease. Dysfunction of energetic homeostasis and the interaction of adiponectin, leptin and tumour necrosis factor-alpha are key events in the pathogenesis of steatosis and insulin resistance. Insulin resistance represents the frame within which hepatic and extrahepatic non-alcoholic fatty liver disease-related clinical manifestations are to be anticipated and interpreted.