The prevalence of abnormal liver enzymes and metabolic syndrome in obese adolescent females with polycystic ovary syndrome

OBJECTIVES

We sought to determine the prevalence of abnormal liver enzymes suggestive of nonalcoholic steatohepatitis and metabolic syndrome in obese adolescent females with polycystic ovary syndrome.

DESIGN

A retrospective chart review.

PARTICIPANTS

Patients included 39 obese (body mass index Z score >/= 2) adolescent females with a diagnosis of polycystic ovary syndrome. Clinical and biochemical data in these patients were reviewed.

MAIN OUTCOME MEASURES

Aspartate and alanine aminotransferase levels, lipid panel, blood pressure, body mass index, and glucose intolerance were the main outcome measures of the study.

RESULTS

The study showed that 15.4 % (6 of 39) of patients had elevated aminotransferase levels, suggestive of nonalcoholic steatohepatitis, and 43.6 % (17 of 39) of patients qualified as having metabolic syndrome. Finally, 10.2 % (4 of 39) of patients were found to have both liver dysfunction and metabolic syndrome.

CONCLUSION

Liver dysfunction consistent with nonalcoholic steatohepatitis and metabolic syndrome are prevalent in obese adolescent females with polycystic ovary syndrome. Therefore, early screening and further work-up for both disease states are warranted in cases of young adolescent females with polycystic ovary syndrome.

Age-related changes in total and regional fat distribution

Aging is associated with progressive changes in total and regional fat distribution that have negative health consequences. Indeed, a preferential increase in abdominal fat, in particular visceral fat, combined with a decrease in lower body subcutaneous fat are commonly cited in the literature. These age-related changes in body composition can occur independent of changes in total adiposity, body weight or waist circumference, and represent a phenotype closely associated with increased morbidity and mortality risk. Tissues such as the heart, liver and skeletal muscle in the elderly have increased fat deposition, which increases risk for insulin resistance and cardiovascular disease. Furthermore, aging is associated with increased fat content within bone marrow, which exposes the elderly to fracture risk beyond that associated with low bone mineral density alone. Many of the age-associated body compositional changes cannot be detected by simple anthropometric measures alone, and the influence of gender, race or ethnicity, and physical activity patterns on these changes is unclear. This review will explore some of these age-related changes in total and regional fat distribution. Consideration will also be given to the strengths and limitations associated with some of the anthropometric methodologies employed for assessing these changes.

Role of adipose tissue in haemostasis, coagulation and fibrinolysis

Obesity is associated with an increased incidence of insulin resistance (IR), type 2 diabetes mellitus and cardiovascular diseases. The increased risk for cardiovascular diseases could partly be caused by a prothrombotic state that exists because of abdominal obesity. Adipose tissue induces thrombocyte activation by the production of adipose tissue-derived hormones, often called adipokines, of which some such as leptin and adiponectin have been shown to directly interfere with platelet function. Increased adipose tissue mass induces IR and systemic low-grade inflammation, also affecting platelet function. It has been demonstrated that adipose tissue directly impairs fibrinolysis by the production of plasminogen activator inhibitor-1 and possibly thrombin-activatable fibrinolysis inhibitor. Adipose tissue may contribute to enhanced coagulation by direct tissue factor production, but hypercoagulability is likely to be primarily caused by affecting hepatic synthesis of the coagulation factors fibrinogen, factor VII, factor VIII and tissue factor, by releasing free fatty acids and pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukin-1beta and interleukin-6) into the portal circulation and by inducing hepatic IR. Adipose tissue dysfunction could thus play a causal role in the prothrombotic state observed in obesity, by directly and indirectly affecting haemostasis, coagulation and fibrinolysis.

Association of central obesity with the severity and audiometric configurations of age-related hearing impairment

To investigate the effect of central obesity on the severity and characteristics of age-related hearing impairment (ARHI), we recruited 690 adult subjects with normal or symmetrical sensorineural hearing loss (SNHL). The effects of age, gender, morphometry, habits, systemic diseases, and environmental noise exposure on average pure tone hearing level at low frequencies (pure tone audiometry (PTA)-low) and high frequencies (PTA-high) were analyzed. After adjusting for age, gender, systemic disease, and other variables, waist circumference (WC) showed a significant positive association with PTA-low and PTA-high. In females, PTA-low and PTA-high only showed significant positive association with age, but not with WC or other variables. However, PTA-high showed a positive association with borderline significance with WC in female subjects older than 55. In males, WC as well as age and noise exposure showed significant positive associations with both PTA-low and PTA-high, primarily in subjects younger than 55. When both WC and BMI were taken into account in a backward stepwise multivariate linear regression analysis, WC, but not BMI, showed a significant positive association with PTA-low and PTA-high in males younger than 55, and with PTA-high with borderline significance in females older than 55. However, the audiogram patterns were not significantly affected by central obesity in either age or gender. Our results suggest that WC was, even after adjustment for BMI, an independent risk factor of ARHI, particularly for low and high frequencies in males younger than 55 and for high frequencies in female subjects older than 55.

Effects of estrogen and androgen deprivation on the progression of non-alcoholic steatohepatitis (NASH) in male Sprague-Dawley rats

AIM

We studied the mechanisms of estrogen/androgen involvement in the induction of NASH by treating Sprague-Dawley (SD) rats fed with a normal or high fat (HF) diet by depriving them of endogenous estrogens/androgens.

METHODS

Male adult SD rats (n = 10/group) on normal or HF diets were treated for 75 days either with tamoxifen (Tam) or flutamide (Flu) or Tam + Flu in order to induce NASH. We analyzed histopathologically the liver samples from the treated groups for NASH, checked the serum biochemical and lipid profile markers and finally analyzed the signal pathways underlying the molecular mechanisms for the induction process of NASH.

RESULTS

Deprivation of endogenous estrogens and/or androgens (Tam or Flu or Tam + Flu) without the HF diet did not induce NASH. Tam or Tam + Flu induced NASH, compared to milder lesions without fibrosis in HF diet and Flu-treated liver. Serum alanine aminotransferase or lipid profile markers further proved the Tam, Flu or Tam + Flu effects on the induction of NASH in conjunction with a HF diet. Tam treatment predominantly downregulated the ERalpha and FAS and upregulated UCP2 and TNF-alpha.

CONCLUSIONS

Deprivation of endogenous estrogen/androgens in conjunction with a HF diet may induce NASH where the downregulated ERalpha and FAS, and upregulated UCP2 and TNF-alpha could be involved in their molecular pathomechanism pathways. These results could suggest the potential negative roles of estrogenic/androgenic depriving compounds in the induction of NASH, along with obesity.

Advances in research on the role of phosphatidylinositol-3 kinase in the pathogenesis of nonalcoholic fatty liver disease

Due to improvement in living standards, changes in eating habits, as well as a sharp increase in the incidence of diabetes and metabolic syndrome, the incidence of nonalcoholic fatty liver disease is continuously increasing. Recent studies have shown that the phosphatidylinositol 3-kinase (PI-3K) pathway plays a crucial role in the pathogenesis of nonalcoholic fatty liver disease. In this article, we will review the role of PI-3K in the pathogenesis of nonalcoholic fatty liver disease.

Relationships of PAI-1 levels to central obesity and liver steatosis in a sample of adult male population in southern Italy

To analyse the relationship of PAI-1 plasma levels to echographically determined liver steatosis and cardiometabolic risk factors in a randomly selected sample of 254 adult male participants of the Olivetti Heart Study. Accounting for age and ongoing pharmacological treatment, PAI-1 levels were directly (P < 0.005) associated with body mass index (BMI), waist circumference (WC), serum triglyceride (TG), total cholesterol, insulin, homeostasis model assessment index, gamma-glutamyl transpeptidase and peritoneal fat. At multiple linear regression (MLR) analysis, measures of adiposity and TG exerted significant and quantitatively similar effects on PAI-1 levels. A progressive rise in PAI-1 level was detected with increasing degree of steatosis. A stepwise MLR model was used to evaluate the relative power of cardiometabolic risk factors and liver steatosis on PAI-1 levels. Adjusting for alcohol intake, BMI, WC and peritoneal fat were alternatively included in the model with other variables found to be significantly associated with plasma PAI-1 level. Liver steatosis, serum TG and various indexes of adiposity each had a significant independent impact on PAI-1 plasma level and explained overall 23% of its variability. Abdominal fat, liver steatosis and serum TG levels were significant and independent determinants of PAI-1 plasma level in an unselected sample of adult male population upon adjustment for age and therapy.

Targeted disruption of carcinoembryonic antigen-related cell adhesion molecule 1 promotes diet-induced hepatic steatosis and insulin resistance

Carcinoembryonic antigen-related cell adhesion molecule 1 (CC1) is a cell adhesion molecule within the Ig superfamily. The Tyr-phosphorylated isoform of CC1 (CC1-L) plays an important metabolic role in the regulation of hepatic insulin clearance. In this report, we show that CC1-deficient (Cc1(-/-)) mice are prone to hepatic steatosis, as revealed by significantly elevated hepatic triglyceride and both total and esterified cholesterol levels compared with age-matched wild-type controls. Cc1(-/-) mice were also predisposed to lipid-induced hepatic steatosis and dysfunction as indicated by their greater susceptibility to store lipids and express elevated levels of enzymatic markers of liver damage after chronic feeding of a high-fat diet. Hepatic steatosis in the Cc1(-/-) mice was linked to a significant increase in the expression of key lipogenic (fatty acid synthase, acetyl CoA carboxylase) and cholesterol synthetic (3-hydroxy-3-methylglutaryl-coenzyme A reductase) enzymes under the control of sterol regulatory element binding proteins-1c and -2 transcription factors. Cc1(-/-) mice also exhibited impaired insulin clearance, glucose intolerance, liver insulin resistance, and elevated hepatic expression of the key gluconeogenic transcriptional activators peroxisome proliferator-activated receptor-gamma coactivator-1 and Forkhead box O1. Lack of CC1 also exacerbated both glucose intolerance and hepatic insulin resistance induced by high-fat feeding, but insulin clearance was not further deteriorated in the high-fat-fed Cc1(-/-) mice. In conclusion, our data indicate that CC1 is a key regulator of hepatic lipogenesis and that Cc1(-/-) mice are predisposed to liver steatosis, leading to hepatic insulin resistance and liver damage, particularly when chronically exposed to dietary fat.

Impact of metabolic syndrome on elevated serum alanine aminotransferase levels in the Japanese population

Measurement of the serum alanine aminotransferase (ALT) level is used as an initial test for detection of liver diseases, and recent studies have also highlighted its potential value as a measure of overall health and survival as a marker of an increased risk of metabolic disorder. This study was designed to clarify the prevalence of elevated ALT levels in the Japanese population and to assess factors associated with ALT elevation. The subjects were 2165 individuals aged 40 to 85 years who participated in a Japanese community-based study referred to as the Takahata Study. Serum ALT levels and factors associated with ALT elevation were investigated. Among 2087 subjects who were negative for hepatitis B and C, the rates of elevated ALT greater than 30 U/L in men and greater than 25 U/L in women were 217 (22.7%) of 957 and 239 (21.2%) of 1130, respectively. These ALT cutoff levels had a specificity of more than 80% for exclusion of subjects with none or 1 of 3 metabolic risk factors: hypertension, lipid metabolism abnormality, and hyperglycemia. Multivariate analysis revealed 5 factors with a significant association with ALT elevation in men (n = 957): high gamma-glutamyltranspeptidase, low adiponectin, high low-density lipoprotein cholesterol, high body mass index, and high homeostasis model assessment insulin resistance index. Similarly, 4 factors were significantly associated with ALT elevation in women (n = 1130): high gamma-glutamyltranspeptidase, low adiponectin, high body mass index, and high homeostasis model assessment insulin resistance index. These results suggest that elevated ALT levels in the Japanese population older than 40 years have a strong association with metabolic syndrome-related features including obesity and insulin resistance.

Prevalence and risk factors for non-alcoholic fatty liver disease among adults in an urban Sri Lankan population

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) is an emerging problem in the Asia-Pacific region. However, its prevalence and risk factors in Asian (especially South Asian) communities is poorly studied. In this study, the aim was to determine the community prevalence and risk factors for NAFLD among adults in an urban Sri Lankan population.

METHODS

The study population consisted of 35-64-year-old adults, selected by stratified random sampling. NAFLD was diagnosed on established ultrasound criteria for fatty liver, safe alcohol consumption (< 14 units/week for men, < 7 units/week for females) and absence of hepatitis B and C markers. Blood pressure (BP) and anthropometric measurements were made, and fasting glucose, glycosylated hemoglobin, serum lipids, fasting serum insulin and serum alanine aminotransferase (ALT) were determined.

RESULTS

Of the 2985 study participants, 974 (32.6%) had NAFLD (605 [62.1%] women, mean age 52.8 years [standard deviation, 7.3]). On multivariate analysis, obesity, acanthosis nigricans, insulin resistance, elevated diastolic BP, fasting plasma glucose, plasma triglycerides, and ALT twice the upper limit of the reference range or more were independently associated with NAFLD.

CONCLUSION

The prevalence of NAFLD among adults in this urban Sri Lankan community is high and is strongly associated with constituent features of the metabolic syndrome.

Predictive factors for the development or regression of Fatty liver in Japanese adults

Fatty liver is commonly associated with alcohol or metabolic syndrome. We aimed to examine the longitudinal aspects of fatty liver, and clarify the independent predictors for the development or regression of fatty liver. In the present study, the clinical features of 1578 Japanese adults (1208 men and 370 women; 35 to 69 years of age) who visited our center both in 2000 and 2007–2008 were recorded and compared, including liver status diagnosed by ultrasonography. Of the 1578 participants, 217 (13.8%) showed fatty liver development, and 74 (4.7%) showed fatty liver regression. Logistic regression analysis revealed that body mass index and percentage body fat were strongly associated with the development or regression of fatty liver. Metabolic syndrome-related disorders such as serum levels of total cholesterol, triglyceride, uric acid, and fasting blood glucose were also associated with clinical course to some degree. However, the history of alcohol intake, the presence of metabolic syndrome, blood pressure, and habitual physical exercise were not independent predictors for the development or regression of fatty liver. Our present data suggest that control of body weight in men and the percentage body fat in women are particularly important for the prevention or treatment of fatty liver.

Carbon tetrachloride-induced liver disease in rats: the potential effect of supplement oils with vitamins E and C on the nutritional status

The aim of the present investigation was to study the effects of olive oil (OO), corn oil (CO), and flaxseed oil (FO), with or without supplementation of vitamins E and C, on food intake, body weight gain %, liver weight to body weight %, total lipids, liver functions, and liver histology in male rats intoxicated with carbon tetrachloride (CCl(4)). Forty-two rats were divided into two main groups. The first main group was fed on basal diet (BD) as a negative control group (NC). The second main group received subcutaneous injections of CCl(4) in paraffin oil (50% v/v 2 ml/kg) twice a week to induce chronic damage in the liver. The group was then divided into six subgroups, three of which were fed on 4% unsupplemented oils (CO, FO, and OO) as positive control for the three oils used. The rest of the groups were fed on 4% of the same oils supplemented with vitamins E and C. The results of the flaxseed oil rat group indicate that supplementing vitamin E and C led to a significant reduction in the mean values of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and liver alanine amino transferase enzyme (ALT). Moreover, it caused an increase of the mean value of high-density lipoprotein cholesterol (HDL-C) as compared to the negative control group (NC). The olive oil group supplemented with the same vitamins showed a significant decrease in the mean value of serum TC and significant (P<0.05) increase in the mean value of serum HDL-C as compared to NC. The results of the corn oil group supplemented with vitamins showed a significant increase in the mean value of serum HDL-C as compared to the negative control group. The histology results confirmed that the group hepatically injured with CCl(4) treatment and fed on supplemented FO or OO showed apparently normal hepatocytes.

CONCLUSION

The most effective treatment was observed with oils supplemented with vitamins E and C. Hierarchically FO achieved the best results compared to other additives, followed by OO and finally CO showing the least effective treatment among the observed groups.

Resveratrol amplifies profibrogenic effects of free fatty acids on human hepatic stellate cells

AIM

To ascertain whether resveratrol affects the expression of free fatty acids (FFA)-induced profibrogenic genes, death receptors, and/or apoptosis-related molecules in human hepatic stellate cells, using the LX-2 cell line.

METHODS

Cells were cultured in the presence of FFAs (2:1 oleate : palmitate) and subsequently treated with resveratrol. Gene expression rates were determined by quantitative real-time PCR. The 50% lethal dose (LD(50)) of resveratrol in the presence of FFAs was assessed with the MTT viability test.

RESULTS

Compared to vehicle controls, incubation of LX-2 cells with 0.5 mM FFAs induced profibrogenic genes (alpha-SMA x 2.9; TGF-beta1 x 1.6; TIMP-1 x 1.4), death receptors (CD95/Fas x 3.8; TNFR-1 x 1.4), and anti-apoptotic molecules (Bcl-2 x 2.3; Mcl-1 x 1.3). Subsequent addition of 15 microM resveratrol (LD(50) = 23.2 microM) significantly (P < 0.05) upregulated further these genes (alpha-SMA x 6.5; TGF-beta1 x 1.9; TIMP-1 x 2.2; CD95/Fas x 13.1, TNFR-1 x 2.1; Bcl-2 x 3.6; Mcl-1 x 1.9). Importantly, this effect was only observed in the presence of FFAs.

CONCLUSION

Resveratrol amplifies the profibrogenic activation of human hepatic LX-2 stellate cells. This finding raises the possibility that in obese patients with elevated FFAs reserveratrol could provoke hepatic fibrogenesis. In-vivo studies are necessary to further validate this conclusion.

Metabolic disturbances in non-alcoholic fatty liver disease

NAFLD (non-alcoholic fatty liver disease) refers to a wide spectrum of liver damage, ranging from simple steatosis to NASH (non-alcoholic steatohepatitis), advanced fibrosis and cirrhosis. NAFLD is strongly associated with insulin resistance and is defined by accumulation of liver fat >5% per liver weight in the presence of <10 g of daily alcohol consumption. The exact prevalence of NAFLD is uncertain because of the absence of simple non-invasive diagnostic tests to facilitate an estimate of prevalence. In certain subgroups of patients, such as those with Type 2 diabetes, the prevalence of NAFLD, defined by ultrasound, may be as high as 70%. NASH is an important subgroup within the spectrum of NAFLD that progresses over time with worsening fibrosis and cirrhosis, and is associated with increased risk for cardiovascular disease. It is, therefore, important to understand the pathogenesis of NASH and, in particular, to develop strategies for interventions to treat this condition. Currently, the 'gold standard' for the diagnosis of NASH is liver biopsy, and the need to undertake a biopsy has impeded research in subjects in this field. Limited results suggest that the prevalence of NASH could be as high as 11% in the general population, suggesting there is a worsening future public health problem in this field of medicine. With a burgeoning epidemic of diabetes in an aging population, it is likely that the prevalence of NASH will continue to increase over time as both factors are important risk factors for liver fibrosis. The purpose of this review is to: (i) briefly discuss the epidemiology of NAFLD to describe the magnitude of the future potential public health problem; and (ii) to discuss extra- and intra-hepatic mechanisms contributing to the pathogenesis of NAFLD, a better understanding of which may help in the development of novel treatments for this condition.

Association of serum uric acid level with non-alcoholic fatty liver disease: a cross-sectional study

BACKGROUND/AIM

Serum uric acid level has been suggested to be associated with factors that contribute to the metabolic syndrome. The aim of this study was to investigate the association of serum uric acid level with non-alcoholic fatty liver disease (NAFLD).

METHODS

A cross-sectional study was performed among the employees of Zhenhai Refining & Chemical Company Ltd., Ningbo, China.

RESULTS

The study included 8925 subjects (6008 men) with a mean age of 43 years. The prevalence rates of NAFLD and hyperuricemia were 11.78% and 14.71%, respectively. NAFLD patients had significantly higher serum uric acid levels than controls (370.3+/-86.6 vs. 321.1+/-82.6 micromol/L; P<0.001). The prevalence rate of NAFLD was significantly higher in subjects with hyperuricemia than in those without hyperuricemia (24.75% vs. 9.54%; P<0.001), and the prevalence rate increased with progressively higher serum uric acid levels (P value for trend <0.001). Multiple regression analysis showed that hyperuricemia was associated with an increased risk of NAFLD (odds ratio [OR]: 1.291, 95% confidence interval [CI]: 1.067-1.564; P<0.001).

CONCLUSION

Serum uric acid level is significantly associated with NAFLD, and elevated serum uric acid level is an independent risk factor for NAFLD.

Prevention of hepatocellular carcinoma in nonviral-related liver diseases

Although chronic infection with hepatitis B virus and/or hepatitis C virus are the most important risk factors for hepatocellular carcinoma (HCC) worldwide, other causes of cirrhosis can also lead to HCC. Given the high prevalence of alcoholism and the worldwide obesity epidemic, the relevant importance of nonviral liver disease-related HCC is expected to increase in the future. Some evidence supports mechanistic interactions between host or environmental factors and chronic viral hepatitis in the development of HCC. For example, food- and water-borne carcinogens have contributed to unusually high rates of HCC in parts of China and sub-Saharan Africa. With some of these conditions, appropriate public health measures to reduce the population's exposure to known etiologic agents, or early therapeutic intervention for 'at-risk' individuals before development of cirrhosis (e.g. hereditary hemochromatosis) can prevent HCC. Community-based programs to discourage and deal with excessive alcohol intake, to promote tobacco smoking awareness, to avoid exposure to aflatoxin and other food toxins, and measures to reduce the pandemic of obesity and diabetes are vital for effective interruption of the rising tide of HCC from nonviral liver disease.

A review of the natural history of chronic hepatitis B in the era of transient elastography

Understanding the natural history of chronic hepatitis B is important in order to predict the prognosis, to stratify the risk of hepatocellular carcinoma and to select appropriate candidates for antiviral treatment. Liver fibrosis is the pathogenic process that leads to liver cirrhosis. The study of liver fibrosis in the past has largely been hampered by the invasive nature of a liver biopsy. Most liver biopsy series represent biased populations with more active disease. Transient elastography is a reliable and non-invasive measurement of liver fibrosis that allows the study of liver fibrosis among patients without clinical indication for liver biopsy. Large studies using transient elastography in patients with predominantly normal alanine aminotransferase levels have been reported recently. The different roles of patient age, hepatitis B virus DNA and alanine aminotransferase levels in the risk stratification for advanced liver fibrosis have been defined in hepatitis B e antigen-positive and hepatitis B e antigen-negative chronic hepatitis B patients. The relationship between metabolic syndrome and chronic hepatitis B is also explored. In this review, new insights from studies using transient elastography on the natural history of chronic hepatitis B with special focus on liver fibrosis will be summarized and discussed.

Non-alcoholic steatohepatitis: an overview

Non-alcoholic fatty liver disease (NAFLD) includes a broad spectrum of fat-induced liver injury, ranging from mild steatosis to cirrhosis and liver failure. The presence of obesity and insulin resistance is strongly associated with non-alcoholic fatty liver and a greater risk of advanced disease. We present here a review of the mechanisms involved in the pathogenesis of NAFLD, advances in the diagnosis, and options for treatment.

NAFLD as a risk factor for the development of diabetes and the metabolic syndrome: an eleven-year follow-up study

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) uncommonly results in cirrhosis and liver-related death; however, its impact on the development of metabolic complications remains unclear. We sought to determine whether NAFLD with elevated aminotransaminase (ALT) levels was a risk factor for incident diabetes or the metabolic syndrome (MS) over an 11-year period.

METHODS

Adult residents of Busselton, Western Australia underwent assessment in 1994-1995 as part of the Busselton Health Survey. NAFLD was diagnosed on the basis of a raised ALT (>40 IU/l) after the exclusion of alcohol, viral, metabolic, and autoimmune liver disease. NAFLD and non-NAFLD subjects were reassessed in 2005 for liver complications, diabetes, and the MS.

RESULTS

A total of 358 subjects, 68% male (109 NAFLD, 249 non-NAFLD), mean age (s.d.) 59.9 (11.6) years, attended follow-up 11.1 years after the initial assessment. After excluding subjects with diabetes at baseline, those with NAFLD were more likely to have developed diabetes on follow-up (20/106, 18.9% vs. 15/246, 6.1%; P<0.001). After excluding subjects with MS at baseline, those with NAFLD were more likely to have developed MS at follow-up (27/81, 33.3% vs. 51/226, 22.6%; P=0.056). However, in multivariate logistic regression models, NAFLD was no longer a significant independent predictor of the development of diabetes or MS after adjusting for baseline waist circumference, hypertension, and insulin resistance. None of the subjects developed liver complications.

CONCLUSIONS

Subjects with NAFLD and elevated ALT levels are at an increased risk of developing diabetes and the MS. This may be because of the presence of associated metabolic risk factors.

Influence of ethnicity on histological differences in non-alcoholic fatty liver disease

BACKGROUND/AIMS

Previous studies examining ethnic differences in non-alcoholic fatty liver disease (NAFLD) are limited by small sample sizes and the lack of liver biopsy as a diagnostic modality.

METHODS

We retrospectively examined the influence of ethnicity on the biochemical and liver histological differences in NAFLD patients.

RESULTS

The proportion of African Americans (AA) in the NAFLD sample (total 238 patients; 15.1% AA) was lower than in the base population (68.2%). Median ALT (47 IU/L; p=0.05) and triglyceride (134mg/dL, p=0.002) levels were lower in AA than other ethnicities. AA showed lower degrees of steatosis [odds ratio (OR) 0.44, 95% confidence interval (CI) 0.22-0.89; p=0.02] than Whites. In contrast, Asians showed higher grades of ballooning than Whites (OR 2.67, 95% CI 1.03-6.93; p=0.04) and other ethnicities combined (OR 2.71, 95% CI 1.06-6.92; p=0.04). Hispanics showed a higher rate of Mallory bodies than Whites (OR 2.38, 95% CI 1.05-5.39; p=0.04) and other ethnicities combined (OR 2.41, 95% CI 1.09-5.34; p=0.03).

CONCLUSIONS

African Americans showed a lower degree of steatosis than Whites. In contrast, Asians and Hispanics showed higher grades of ballooning and Mallory bodies, respectively, than Whites and other ethnicities combined. These findings highlight the need for prospective studies to evaluate ethnic differences in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) in nonobese patients with diabetes: Prevalence and relationships with hemodynamic alterations detected with Doppler sonography()

AIM

To evaluate the prevalence, severity, and hemodynamic features of nonalcoholic fatty liver disease (NAFLD) in nonobese diabetics.

METHODS

We studied 100 consecutive nonobese (body mass index [BMI] < 30) patients with type 1 (n = 17) or type 2 (n = 83) diabetes and no known causes of liver disease. Steatosis was diagnosed and graded with ultrasonography. Digital sonographic images of the liver and right kidney were analyzed with dedicated software (HDI-Lab), and the liver/kidney ratio of grey-scale intensity was calculated as an index of the severity of the steatosis. Severity scores ranging from 0 (none) to 5 (severe) were compared with sonographic and Doppler findings (right liver size, portal vein diameter and flow velocity, hepatic and splenic arterial pulsatility indices, hepatic-vein flow profile and A- and S-wave velocities).

RESULTS

The prevalence of steatosis was 24% in type I and 80% in type II diabetes (grade 1 in 17%, grade 2 in 34%, grade 3 in 33%, grade 4 in 9%, grade 5 in 7%). In patients with steatosis (especially those with grades 4-5 disease), hepatic volume was increased (p < 0.005). Portal vein diameter was increased in grade 5 steatosis. The hepatic artery pulsatility index was significantly increased, particularly in grades 4 and 5 (p < 0.0001); portal and A-wave velocities were significantly reduced in grades 3-5 (p < 0.001); and the hepatic vein flow profile was altered in 27% (biphasic: 20%, flat: 7%) patients with steatosis, although there was no correlation with severity.

CONCLUSIONS

NAFLD is very frequent in nonobese diabetics with type 2 but not type 1 disease, and it is associated with hepatomegaly and liver hemodynamic alterations only when it is severe.

Hepatocellular carcinoma in the Asia pacific region

Primary liver cancer, particularly hepatocellular carcinoma (HCC) remains a significant disease worldwide. It is among the top three causes of cancer death in the Asia Pacific region because of the high prevalence of its main etiological agents, chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. In this region, the incidence of HCC has been static over recent decades. Older age is a major risk factor; the incidence increasing sharply after age 40 years. There is a male predilection, with male to female ratio of 3:1, except in elderly Japanese with equal sex incidence or female predominance. In most Asia-Pacific countries, chronic HBV infection accounts for 75-80% of cases; Japan, Singapore and Australia/New Zealand are exceptions because of higher prevalence of HCV infection. In spite of advances in surgery, liver transplantation and newer pharmaco/biological therapies, the survival rate has improved only slightly over recent decades, and this could be attributable to earlier diagnosis ('lead-time bias'). The majority of patients present with advanced diseases, hence reducing the chance of curative treatment. The importance of HCC may decrease in two to three decades when the prevalence of chronic HBV infection decreases as a result of the universal HBV vaccination programs implemented in late 1980s in most Asia-Pacific countries, and because of reduced incidence of medical transmission of HCV. However, transmission of HCV by injection drug use, and rising prevalence of obesity and diabetes, both independent risk factors for HCC, may partly offset this decline.

Relationship between alanine aminotransferase levels and metabolic syndrome in nonalcoholic fatty liver disease

OBJECTIVE

To investigate the relationship between alanine aminotransferase (ALT) levels and metabolic syndrome (MS) in nonalcoholic fatty liver disease (NAFLD).

METHODS

A total of 26527 subjects who received medical health checkup in our hospital from January 2005 to July 2007 were enrolled in the study. The diagnosis of fatty liver was based on ultrasound imaging. MS was defined according to the criteria of the Adult Treatment Panel III. ALT, triglyceride (TG), high density lipoprotein cholesterol (HDL-c), fasting plasma glucose (FPG), height, weight, waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in each subject to analyze the relationship between MS and ALT activity.

RESULTS

(1) The prevalence of NAFLD in men (30.94%) was significantly higher than that in women (15.65%); (2) The incidence of MS in NAFLD (33.83%) was significantly greater than that in non-NAFLD (10.62%); (3) Of the 6470 subjects with NAFLD, in the age-adjusted partial correlation analysis, there were statistically significant correlations between the ALT levels and most metabolic risk factors in each sex (P<0.01), except that ALT levels had no correlation with HDL-c in women. Moreover, in the multiple stepwise regression analysis, SBP lost its significance, and WC, body mass index (BMI), age, DBP, TG and FPG were independently associated with ALT levels in both sexes (P<0.05). HDL-c remained significant and was independently related to ALT levels in men; (4) ALT levels were significantly higher in subjects with MS compared to those without MS (P<0.001). Mean ALT levels increased with the number of MS components in each sex (P<0.05 for trend).

CONCLUSION

We found a strong relationship between ALT levels and MS in NAFLD and revealed that the cluster of MS components might be the predictor for ALT elevations.

Metabolic and histological features of non-alcoholic fatty liver disease patients with different serum alanine aminotransferase levels

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. Serum alanine aminotransferase (ALT) level is commonly performed to monitor NAFLD patients, but its clinical relevance is unclear.

AIM

To evaluate the metabolic and histological features of NAFLD patients with different ALT levels.

METHODS

A total of 173 consecutive patients with biopsy-proven NAFLD were studied. Patients with persistently normal ALT and those with abnormal ALT were compared.

RESULTS

Patients with persistently normal ALT had lower steatosis grade than patients with abnormal ALT, but they had similar degree of lobular inflammation, ballooning and fibrosis. Among 19 patients with ALT below 0.5 times the upper limit of normal (ULN) at the time of liver biopsies, 8 (42%) and 3 (16%) had steatohepatitis and significant fibrosis respectively. The within-patient coefficient of variance was similarly high in patients with simple steatosis and steatohepatitis (33.5). Age and glucose, but not ALT, were independent factors associated with significant fibrosis.

DISCUSSION

Metabolic factors, but not ALT, are associated with histological severity. Patients with ALT < 0.5 x ULN may still have non-alcoholic steatohepatitis (NASH) and significant fibrosis. Evaluation of NAFLD patients should be based on metabolic risk factors, but not ALT level.

The roles of obesity and gender on the relationship between metabolic risk factors and non-alcoholic fatty liver disease in Koreans

BACKGROUND

The effect of gender and weight status on the association between metabolic risk factors and NAFLD has not been well established. This study aimed to assess the relationships among obesity, gender, metabolic risk factors, and non-alcoholic fatty liver disease (NAFLD) in Korean adults.

METHODS

Abdominal ultrasounds, anthropometric measurements, and biochemical tests were performed on 13,768 Korean adults (7,313 men and 6,455 women) recruited from a health promotion centre between 2005 and 2006.

RESULTS

Of 13,768 subjects, 25% were diagnosed with NAFLD. Weight status (obesity vs non-obesity, odds ratio (OR) 4.4-9.7) and gender (women vs men, OR 0.6) were associated with NAFLD after adjusting for age, metabolic risk factors (high blood pressure, high glucose, high TG, low HDL, high LDL, and high uric acid), and gamma-glutamyl transferase (gammaGT). For subjects with any one risk factor, the OR (95% CI) for mild fatty liver was 27 (19.3-37.8) in men and 7.9 (6.1-10.2) in women who were obese compared to non-obese individuals having no risk factors. The ORs in men and women who were not obese were 4.7 (3.9-5.6) and 2.5 (2.2-3.0), respectively. The sensitivity and specificity for NAFLD with any one risk factor without obesity was 90-91 and 32-49%, respectively; any one risk factor combined with obesity changed the sensitivity and specificity to 64-67 and 77-85%, respectively.

CONCLUSIONS

Gender and weight status appear to modify the relationship between metabolic risk factors and NAFLD.

Long-term follow-up of patients with nonalcoholic fatty liver

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of conditions ranging from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH) convincingly. NASH is the only subtype of NAFLD that has been shown to progress relatively, although these findings were reported from studies with short follow-up periods. We assessed the long-term outcomes of a NAFLD cohort.

METHODS

Patients with NAFLD established by biopsy were identified in databases and categorized as NASH or non-NASH. Mortality data and causes of death were obtained from National Death Index Plus. The nonparametric Kaplan-Meier method with log-rank test and multivariate analyses with a Cox proportional hazard model were used to compare different NAFLD subtypes and to identify independent predictors of overall and liver-related mortality.

RESULTS

Of 173 NAFLD patients (age at biopsy, 50.2 +/- 14.5 y; 39.9% male; 80.8% Caucasian; 28.9% with type II diabetes), 72 (41.6%) had NASH and 101 (58.4%) had non-NASH NAFLD. Over the follow-up period, the most common causes of death were coronary artery disease, malignancy, and liver-related death. Although overall mortality did not differ between the NAFLD subtypes, liver-related mortality was higher in patients with NASH (P < .05). Independent predictors of liver-related mortality included histologic NASH, type II diabetes, older age at biopsy, lower albumin levels, and increased levels of alkaline phosphatase (P < .05).

CONCLUSIONS

This long-term follow-up evaluation of NAFLD patients confirms that NASH patients have increased liver-related mortality compared with non-NASH patients. In addition, patients with NAFLD and type II diabetes are especially at risk for liver-related mortality.

The Risk Factors for Ultrasound-diagnosed Non-alcoholic Fatty Liver Disease Among Adolescents

Introduction: Non-alcoholic fatty liver disease (NAFLD) is garnering increasing interest and acceptance as one of the most important causes of chronic liver disease. The aim of this study was to investigate the risk factors for NAFLD among selected adolescent students in Hualien City, Taiwan. Materials and Methods: A stratified random sampling scheme was carried out among 1724 adolescent students aged 12 or 13 years old in Hualien City. In total, 220 students (normal: overweight: obese = 97:48:75) agreed to join the study. They underwent physical examination, laboratory tests and ultrasonography examination of the liver. Diagnosis of NAFLD in this study was based on sonographic evidence of a fatty liver and testing negative for serum HBsAg and anti- HCV antibody. Results: Of the 220 participants, 4 were excluded because they tested positive for HBsAg or anti-HCV antibody. NAFLD was detected in 86 (39.8%) out of the 216 subjects. The rate of NAFLD in the adolescents increased progressively from 16.0% in the normal group to 50.5% in the overweight group, and 63.5% among the obese subjects. Compared to their normal counterparts, adolescents with NAFLD had a significantly higher weight, body mass index (BMI), waist circumference, levels of alanine aminotransferase (ALT), triglyceride and non- high-density-lipoprotein (non-HDL) cholesterol. However, among the participants with NAFLD, only 20 (23.3%) showed ALT abnormality but there was an increasing trend of ALT abnormality as the severity of fatty liver increased. In addition, the higher ALT, Homeostasis model assessment- insulin resistance (HOMA-IR), cholesterol, triglyceride, and non-HDL levels and lower HDL-C as the severity of fatty liver increased. In a stepwise logistic regression analysis, the most significant factor associated with the presence of NAFLD was weight category. When compared with their normal counterparts, overweight and obese adolescents had a 4.14 and 5.98 times the risk of having NAFLD, respectively. Elevated ALT was the second most important factor as adolescents with elevated ALT were more likely to have NAFLD (odds ratio = 3.32, 95% CI: 1.16 to 9.50). Non-HDL cholesterol level was the third most important factor associated with NAFLD with a 3.81-fold increase in risk incurred for every l n (1 mg/dL) increment. Conclusions: Obesity, ALT abnormality and elevated non-HDL-cholesterol are risk factors for NAFLD in adolescents. However, only 23.3% of the adolescents with NAFLD showed an abnormality for ALT. Therefore, ALT alone is not a sufficient indicator; and it is recommended that ultrasonog- raphy of the liver should be part of the routine health examination of obese adolescents. Key words: Adolescents, Non-alcoholic fatty liver disease, Obese, Risk factors

Epidemiology of non-alcoholic fatty liver disease in China

Fatty liver (steatosis) is highly prevalent in China and is more often linked to obesity than to alcoholism. Among more affluent regions of China, the community prevalence of non-alcoholic fatty liver disease (NAFLD) is approximately 15%. With the increasing pandemic of obesity, the prevalence of NAFLD has approximately doubled in the past decade. The risk factors resemble those in other ethnic populations, but it is important to note that ethnic-specific definitions of central obesity, obesity and metabolic syndrome are more useful in assessment of Chinese people. The full range of histological manifestations of NAFLD has been demonstrated in Chinese patients, but to date hepatic severity is generally mild. In contrast to chronic hepatitis C, steatosis is less common in patients with chronic hepatitis B; it is associated with metabolic, and not viral factors and does not appear to affect disease severity. Although long-term outcomes of NAFLD in Chinese populations remain unclear, it may be a predictor of metabolic disorders, diabetes and cardiovascular disease. Public health interventions are therefore indicated to halt or reverse the national trend of obesity in China so as to improve liver as well as metabolic health.

Epidemiology and natural history of non-alcoholic fatty liver disease (NAFLD)

The authors summarize and update the most recent knowledge in the field of prevalence, natural history and incidence of Non Alcoholic Fatty Liver Disease (NAFLD) and Non Alcoholic Steatohepatitis (NASH). These novel diseases, firstly recognized at the beginning of the second millennium, arose suddenly to the attention of the clinicians, because they are the hepatic expression of the "so-called" metabolic syndrome. Due to the epidemic burden of obesity, diabetes, and metabolic diseases, NAFLD and NASH will become soon probably the most common hepatic disease worldwide, and they surely will keep busy our future young hepatologists.

Non-alcoholic fatty liver disease and its association with obesity, insulin resistance and increased serum levels of C-reactive protein in Hispanics

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder of the liver, which may progress to fibrosis or cirrhosis. Recent studies have shown a significant impact of ethnicity on susceptibility to steatosis-related liver disease.

AIMS

To estimate the prevalence of NAFLD among Chilean Hispanics as well as the clinical and biochemical variables associated with the disease.

METHODS

Population-based study among Chilean Hispanics. The diagnosis of NAFLD was made on the basis of ultrasound evidence of fatty liver and absence of significant alcohol consumption and hepatitis C virus infection.

RESULTS

A total of 832 Hispanic subjects were included. Ultrasound findings revealed diffuse fatty liver in 23% of the subjects. Variables associated with fatty liver in multivariate analysis were body mass index >26.9 [odds ratio (OR) 6.2; 95% confidence interval (CI) 3.3-11.5], abnormal aspartate aminotransferase levels (OR 14; 95% CI 8.2-23.7), presence of insulin resistance as measured by homoeostasis model assessment-insulin resistance (OR 3; 95% CI 1.8-4.8) and serum levels of high-sensitivity C-reactive protein (hs-CRP) greater than 0.86 mg/L (OR 2.9; 95% CI 1.6-5.2). Among subjects with NAFLD, levels of hs-CRP were similar regardless of the alanine aminotransferase (ALT) level.

CONCLUSIONS

Chilean Hispanics exhibit a high prevalence of NAFLD. Obesity, insulin resistance, abnormal aminotransferase levels and elevated hs-CRP were independently associated with the presence of NAFLD. ALT elevation underestimates the presence of ultrasonographical fatty liver, whereas hs-CRP is a sensitive independent marker of NAFLD, which may be useful for detecting fatty liver in the general population.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the United States and, indeed, worldwide. It has become a global public health issue. In the United States, the prevalence in the general population is estimated at approximately 20%, while that in the morbidly obese population at approximately 75-92% and in the pediatric population at approximately 13-14%. The progressive form of NAFLD, nonalcoholic steatohepatitis, is estimated at approximately 3-5%, with approximately 3-5% of these having progressed to cirrhosis. Thus, the numbers of individuals at risk for end-stage liver disease and development of primary liver cancer is large. NAFLD is an independent risk factor for cardiovascular disease, leads to increased all-cause mortality, and to increased liver-related mortality. This review focuses on recent advances in our understanding of the NAFLD disease spectrum, including etiology, diagnosis, treatment, and genetic and environmental risk factors and suggests future directions for research in this important area.

Detection of TNF-α, TGF-β1 and hs-CRP and its clinical significance in non-alcoholic fatty liver disease

AIM: To examine expression and clinical significance of serum TNF-α, TGF-β1 and hs-CRP in non-alcoholic fatty liver disease.

METHODS: A total of 51 cases with simple steatosis, 48 cases with non-alcoholic steatohepatitis and 32 controls were enrolled from department of gastroenterology in the third hospital of Wuhan. Serum level of hs-CRP was determined and serum TNF-α and TGF-β1 levels were detected using ELISA method.

RESULTS: Results showed that TNF-α, TGF-β1 and hs-CRP were independent risk factors for non-alcoholic fatty liver disease. The levels of serum hs-CRP and TNF-α were significantly higher in non-alcoholic steatohepatitis patients than in simple steatosis patients (3.92 ± 1.41 vs 2.01 ± 0.39, 8.13 ± 4.21 vs 3.97 ± 0.94, both P < 0.05). However, no significant difference was observed in serum level of TGF-β1 between simple steatosis and non-alcoholic steatohepatitis groups.

CONCLUSION: TNF-α and hs-CRP could be used to differentiate patients with non-alcoholic steatohepatitis from simple steatosis.

Dietary resveratrol alters lipid metabolism-related gene expression of mice on an atherogenic diet

BACKGROUND/AIMS

Resveratrol, a polyphenolic activator of the silent information regulation 2 homolog 1 (SIRT1), is known to extend lifespan and improve metabolic disease. The aim of the present study is to test whether resveratrol protects against metabolic steatohepatitis through the modulation of lipid metabolism-related genes.

METHODS

We used a mouse model in which steatohepatitis can be induced by an atherogenic diet (Ath diet) to evaluate the effects of resveratrol on steatotic hepatitis and hepatic gene expression.

RESULTS

The Ath diet induced excessive weight gain, hepatomegaly, dyslipidemia, and steatohepatitis after 8 weeks. The addition of resveratrol protected against Ath diet-induced changes and also alleviated steatohepatitis. Whole-genome expression analysis revealed that an Ath diet altered the hepatic expression of genes involved in lipid metabolism, and the addition of resveratrol to the diet reversed that effect. Real-time PCR and Western blot analysis confirmed the Ath diet up-regulated the levels of genes related to lipogenesis and down-regulated genes involved in lipolysis. Resveratrol clearly suppressed the Ath diet-induced alterations of the expression of genes related to lipid metabolism.

CONCLUSIONS

Resveratrol ameliorated dyslipidemia and steatohepatitis induced by the Ath diet, and its beneficial effects were associated with the altered expression of hepatic genes involved in lipid metabolism.

Disease-specific mechanisms of fibrosis: hepatitis C virus and nonalcoholic steatohepatitis

Our mechanistic understanding of liver fibrosis has increased dramatically in recent years for all liver diseases and for hepatitis C and nonalcoholic steatohepatitis (NASH) in particular. Hepatitis C causes liver injury and fibrosis through direct cytopathic means, direct and indirect interactions with hepatic stellate cells, and activation of the immune system. Steatosis and insulin resistance, which are intrinsic deficits in NASH, are also of great importance in hepatitis C and may be induced by viral or host metabolic factors. For NASH, the key mediators of damage include oxidative stress, fat compartmentalization, visceral fat, apoptosis, and adipokine derangement. This article explores in depth the disease-specific mechanisms of fibrosis in hepatitis C and NASH, with a focus on recent developments.

Animal models of NASH: getting both pathology and metabolic context right

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of referral to liver clinics, and its progressive form, non-alcoholic steatohepatitis (NASH), can lead to cirrhosis and end-stage liver disease. The main risk factors for NAFLD/NASH are the metabolic abnormalities commonly observed in metabolic syndrome: insulin resistance, visceral obesity, dyslipidemia and altered adipokine profile. At present, the causes of progression from NAFLD to NASH remain poorly defined, and research in this area has been limited by the availability of suitable animal models of this disease. In the past, the main models used to investigate the pathogenesis of steatohepatitis have either failed to reproduce the full spectrum of liver pathology that characterizes human NASH, or the liver pathology has developed in a metabolic context that is not representative of the human condition. In the last few years, a number of models have been described in which the full spectrum of liver pathology develops in an appropriate metabolic context. In general, the underlying cause of metabolic defects in these models is chronic caloric overconsumption, also known as overnutrition. Overnutrition has been achieved in a number of different ways, including forced feeding, administration of high-fat diets, the use of genetically hyperphagic animals, or a combination of these approaches. The purpose of the present review is to critique the liver pathology and metabolic abnormalities present in currently available animal models of NASH, with particular focus on models described in approximately the last 5 years.

Obesity-associated liver disease

CONTEXT

In the last few years, several data have accumulated suggesting that obesity may be associated with liver disease and disease progression. Accordingly, the worldwide epidemic of obesity is likely to become a relevant source of morbidity and mortality in the general population.

EVIDENCE ACQUISITION

We reviewed the literature on two main issues: 1) the evidence that obesity carries out an increased risk of liver disease, both in the general population and in selected cohorts; and 2) the evidence that obesity is a risk factor for nonalcoholic fatty liver disease and its progression in a series observed in liver units.

EVIDENCE SYNTHESIS

The presence of obesity increases the risk of elevated liver enzymes by a factor of two to three, whereas the risk of steatosis at ultrasonography is increased by a factor of 3 in the presence of overweight and peaks at a factor of approximately 15 in the presence of obesity. Both cirrhosis (cryptogenic cirrhosis) and hepatocellular carcinoma are also associated with obesity in the general population. In patients with nonalcoholic fatty liver disease observed in liver units, obesity and weight gain are systematically associated with advanced fibrosis and fibrosis progression.

CONCLUSION

Liver disease of metabolic origin, associated with obesity, is now recognized as the most prevalent liver disease in Western countries. Strategies are needed to approach obesity-associated liver disease by behavior programs, motivating people to adopt a healthier lifestyle. Such programs should be coupled with public policies at a societal level to obtain the maximum effects in lifestyle changes.

Treatment options for nonalcoholic Fatty liver disease

Nonalcoholic fatty liver disease comprises a range of disorders from steatosis and steatohepatitis through to cirrhosis. Nonalcoholic steatohepatitis can progress to cirrhosis and liver-related death. Therefore, managing this common disorder is becoming an important public health issue. Lifestyle measures are commonly suggested but robust data are lacking. Trials with antioxidants (vitamin E, betaine) as well as cytoprotectants (ursodeoxycholic acid) have been disappointing. While data for insulin sensitizers such as metformin are less conclusive, thiazolidinediones appear promising. However, not all patients respond to thiazolidinediones. Moreover, issues related to weight gain, cardiovascular risk need to be addressed. The use of endocannabinoid antagonists and insulin secretagogues are novel strategies to combat this disorder.

Role of nonalcoholic fatty liver disease in the development of insulin resistance and diabetes

Nonalcoholic fatty liver disease (NAFLD) is a common disease that is usually accompanied by insulin resistance (IR). Whether or how NAFLD and IR are temporally and mechanistically related is controversial. Recent studies focus on their epidemiology, the importance of dietary fat, the role of adipocytokines and the sterol regulatory element-binding protein-1c. NAFLD and IR may progress to severe diseases, such as cirrhosis, diabetes or both, and understanding the pathogenesis of the precursor conditions has preventive and therapeutic implications. This review focuses on the possible relationships between NAFLD and IR and the treatment options available.

Obesity and overweight in relation to liver disease mortality in men: 38 year follow-up of the original Whitehall study

Obesity has been implicated in the aetiology of liver disease. However, to date, evidence is largely drawn from cross-sectional studies, where interpretation is hampered by reverse causality, and from studies on clinical populations that have limited generalisability. In this prospective cohort study, data on body mass index (BMI) and covariates were collected at baseline on 18 863 male government employees (aged 40-69 years). Respondents were then followed up for a maximum of 38 years of age. Mortality surveillance gave rise to 13 129 deaths, 122 of which were due to liver disease (57 cancers; 65 non-cancers). In age-adjusted analyses, BMI was positively related to total liver disease mortality (hazards ratio per 1 s.d. increase in BMI; 95% confidence interval (CI): 1.36; 1.14, 1.62) in a graded fashion across the weight categories (P-value for trend: 0.01). The magnitude of this association was somewhat stronger for non-cancer liver disease deaths (1.47; 1.16, 1.86) than for cancer liver disease deaths (1.25; 0.96, 1.62). Excluding deaths in the first 10 years of follow-up somewhat strengthened the BMI-non-cancer liver disease association. Adjustment for socioeconomic position, other candidate confounders and mediating factors led to the modest attenuation of these associations. Further investigation in prospective cohort studies with more detailed data on liver disease, for instance using biochemical tests of liver function or hepatic ultrasonography, is warranted.

Advance in the molecular pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease and its incidence rate is increasing year by year. In this paper, we investigated and summarized the studies on the mechanisms of NAFLD in recent years, aiming at illustrating the roles of genes in NAFLD and their molecular mechanisms.

Inflammatory change of fatty liver induced by intraportal low-dose lipopolysaccharide infusion deteriorates pancreatic insulin secretion in fructose-induced insulin-resistant rats

BACKGROUND

This study tested whether subacute inflammatory change of fatty liver induced by portal endotoxaemia is detrimental to pancreatic insulin secretion in fructose-fed rats (FFRs) with fatty liver.

METHODS

Rats were randomly assigned into two groups with a regular or fructose-enriched diet for 8 weeks. Rats, after fructose feeding for 4 weeks, were further divided into three subgroups: on fructose diet alone, on fructose diet combined with intraportal saline or lipopolysaccharide (LPS) infusion (n=8 per group) for the next 4 weeks. In another set of experiments, the liver and pancreatic tissues were obtained for histological examination in these four groups. Pancreatic insulin secretion was evaluated by in vivo hyperglycaemic clamp study.

RESULTS

Fasting plasma insulin concentrations and homoeostasis model assessment-insulin resistance, an insulin resistance score, were significantly increased in FFRs but failed to change in rats with LPS treatment. The 4-week intraportal LPS infusion significantly increased circulating aspartate transaminase, alanine transaminase and C-reactive protein levels but did not alter endotoxin levels in FFRs. The increased white blood cell count was also noted in rats after intraportal LPS infusion for 2 and 4 weeks. The attenuated first-phase and second-phase insulin responses in FFRs shown in hyperglycaemic clamp were further deteriorated in those with intraportal LPS infusion. Increased histopathological scores of liver and pancreas shown in FFRs were further increased in those combined with portal endotoxaemia.

CONCLUSION

This study demonstrates that the chronic subacute inflammatory change of fatty liver induced by mild portal endotoxaemia could deteriorate insulin secretion in a rodent model of metabolic syndrome and fatty liver.

Prevalence and risk factors of hepatic steatosis and its impact on liver injury in Chinese patients with chronic hepatitis B infection

BACKGROUND AND AIMS

The clinical significance of hepatic steatosis in chronic hepatitis B infection (CHB) is unclear. The aims of this study were thus to investigate the prevalence and risk factors for hepatic steatosis in patients with CHB and its relationship with liver injury.

METHODS

Consecutive patients with biopsy-proven CHB at Hangzhou Sixth People's Hospital between January 2005 and June 2007 were included. Patients co-infected with other viruses or suffering from liver disease of any other cause were excluded. Liver steatosis, necroinflammation and fibrosis were assessed by both Brunt and Scheuer classifications.

RESULTS

A total of 1915 patients (1497 men) with a mean age of 31 +/- 9.5 years were analyzed. Hepatic steatosis was present in 260 (14%) patients. The steatosis involved < 33% of hepatocytes in 90% of cases, and was more frequent among men than women (15% vs 8%, P < 0.001). Two-thirds (178 of 260) of patients with steatosis were hepatitis B e antigen (HBeAg)-positive, but there was no correlation with either serum HBeAg status or hepatitis B virus DNA titer. Degree of inflammation and fibrosis were more mild among those with steatosis than those without. Multivariate analysis showed that steatosis was independently associated with body mass index, serum triglyceride, apolipoprotein B, uric acid, and fasting blood glucose. However, fibrosis was only independently associated with age and inflammatory grade, and the latter associated with viral load and fibrosis stage.

CONCLUSIONS

Hepatic steatosis is common in CHB, it is associated with metabolic factors not viral ones, and does not appear to affect the severity of liver disease.

Fatty liver and chronic inflammation in Chinese adults

OBJECTIVE

To investigate the significance of fatty liver as predictor of insulin resistance (IR) and chronic inflammation.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 450 adults of Han Chinese origin aged >or=35. Excluded were cases with hepatitis B or C, alcoholic liver disease, or currently using thiazolidinedione. The volunteers were screened for the presence of the components of metabolic syndrome (MtS). IR index was estimated by the homeostasis model assessment. The fatty liver index was evaluated by computed tomography, calculated as the liver/spleen (L/S) ratio arrived at by averaging Hounsfield values obtained for five 3-mm slices. Serum levels of adiponectin, C-reactive protein (CRP), leptin, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were checked in 100 subjects with low-L/S ratio and 100 age- and sex-matched controls.

RESULTS

Fatty liver index correlated with all MtS traits and IR index. The values of L/S ratios in subjects with 0, 1, 2, 3 and >or=4 traits of MtS were 1.25+/-0.13, 1.18+/-0.16, 1.12+/-0.21, 1.05+/-0.25 and 0.92+/-0.25, respectively (p<0.001). In our stepwise regression analysis to compare the L/S ratios to the conventional traits of MtS for association with adipokine dysregulation, we found L/S ratio to be independently associated with most of them: adiponectin (p<0.001), CRP (p<0.001), IL-6 (p=0.005) and TNF-alpha (p=0.014).

CONCLUSION

In Chinese, fatty liver index correlated well with IR index and can be a better marker of chronic inflammation than the conventional components of MtS.

Protein glutathionylation increases in the liver of patients with non-alcoholic fatty liver disease

BACKGROUND AND AIM

Oxidative stress is an important pathophysiological mechanism in non-alcoholic steatohepatitis, where hepatocyte apoptosis is significantly increased correlating with disease severity. Protein glutathionylation occurs as a response to oxidative stress, where an increased concentration of oxidized glutathione modifies post-translational proteins by thiol disulfide exchange. In this study, we analyzed the protein glutathionylation in non-alcoholic fatty liver disease (NAFLD) and evaluated a potential association between glutathionylation, fibrosis, and vitamin E treatment.

METHODS

Protein glutathionylation was studied in the livers of 36 children (mean age 12.5 years, range 4-16 years) subdivided into three groups according to their NAFLD activity score (NAS) by Western blot analysis and immunohistochemistry, using a specific monoclonal antibody. In addition, we identified the hepatocyte ultrastructures involved in glutathionylation by immunogold electron microscopy.

RESULTS

Our findings showed that protein glutathionylation increases in the livers of patients with NAFLD and it is correlated with steatohepatitis and liver fibrosis. Its increase appears mainly in nuclei and cytosol of hepatocytes, and it is reversed by antioxidant therapy with reduced fibrosis.

CONCLUSION

Protein glutathionylation significantly increases in livers with NAFLD, strongly suggesting that oxidative injury plays a crucial role in this disease. Furthermore, the marked increase of protein glutathionylation, in correlation with collagen VI immunoreactivity, suggests a link between the redox status of hepatic protein thiols and fibrosis.