Prevalence of obesity and diabetes in patients with cryptogenic cirrhosis: a case-control study

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.

Aflatoxin exposure and viral hepatitis in the etiology of liver cirrhosis in the Gambia, West Africa

BACKGROUND

Cirrhosis of the liver is thought to be a major cause of morbidity and mortality in sub-Saharan Africa, but few controlled studies on the etiology of cirrhosis have been conducted in this region.

OBJECTIVES

We aimed to elucidate the association between environmental and infectious exposures and cirrhosis in The Gambia.

METHODS

Ninety-seven individuals were diagnosed with cirrhosis using a validated ultrasound scoring system and were compared with 397 controls. Participants reported demographic and food frequency information. Blood samples were tested for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis C virus (HCV) antibody, HCV RNA, and the aflatoxin-associated 249(ser) TP53 mutation.

RESULTS

HBsAg seropositivity was associated with a significant increase in risk of cirrhosis [odds ratio (OR) = 8.0; 95% confidence interval (CI), 4.4-14.7] as was the presence of HBeAg (OR = 10.3; 95% CI, 2.0-53.9) and HCV infection (OR = 3.3; 95% CI, 1.2-9.5). We present novel data that exposure to aflatoxin, as assessed both by high lifetime groundnut (peanut) intake and by the presence of the 249(ser) TP53 mutation in plasma, is associated with a significant increase in the risk for cirrhosis (OR = 2.8; 95% CI, 1.1-7.7 and OR = 3.8; 95% CI, 1.5-9.6, respectively). Additionally, aflatoxin and hepatitis B virus exposure appeared to interact synergistically to substantially increase the risk of cirrhosis, although this was not statistically significant.

CONCLUSIONS

Our results suggest that the spectrum of morbidity associated with aflatoxin exposure could include cirrhosis.

Effect of endurance exercise on hepatic lipid content, enzymes, and adiposity in men and women

Obesity and physical inactivity are independent risk factors for the development of nonalcoholic fatty liver disease (NAFLD). We determined the effect of endurance exercise training on hepatic lipid content and hepatic enzyme concentration in men and women. Waist circumference (WC), percent body fat (BF), computed tomography (CT) scans for liver attenuation (inverse relationship with hepatic lipid), bilirubin, alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) plasma concentrations were measured before and after 12 weeks of endurance training in 41 lean and obese men and women. Exercise training did not change liver attenuation, body weight, percent BF, bilirubin, or ALT concentration, but did lower WC (P < 0.0001), and decreased GGT in men only (P = 0.01). Obese subjects had a lower liver attenuation than lean subjects (P = 0.04). Obese women had lower ALT than obese men (P = 0.03). GGT was lower in women before and after training. WC was positively correlated with GGT (r = 0.32, P = 0.003) and ALT (r = 0.320, P = 0.004) and negatively correlated with liver attenuation (r = -0.340, P = 0.03). Percent BF was negatively correlated with bilirubin (r = -0.374, P = 0.005). Liver attenuation was negatively correlated with ALT (r = -0.405, P = 0.003). Short-term endurance training without weight loss does not alter hepatic lipid content. There was a strong relationship between GGT/ALT and body composition (percent BF) as well as between ALT and hepatic lipid content.

Relationship between insulin resistance and serum alanine aminotransferase as a surrogate of NAFLD (nonalcoholic fatty liver disease) in obese Korean children

There has been increasing number of obese children who accompany obesity-related comorbidities. It has been known that nonalcoholic fatty liver disease (NAFLD) as one of obesity-related comorbidities is related with insulin resistance. So, we investigated the relation between insulin resistance and NAFLD, using serum alanine aminotransferase (ALT) as a surrogate of NAFLD among obese children in Korea. The study subjects were 909 obese children aged 9-12 years (boys 613, girls 296). Body mass index (BMI), waist circumference (WC), blood pressure, fasting blood glucose, fasting insulin, lipid profile were measured. ALT, liver enzyme was used as a surrogate of NAFLD and homeostasis model assessment of insulin resistance (HOMA-IR) was used as the index of insulin resistance. The prevalence of elevated serum ALT (>or=40 mg/dl) was 33.4% in boys, and 19.6% in girls respectively. In boys, ALT was correlated with BMI, waist circumference, total cholesterol, triglyceride, HDL-cholesterol, systolic and diastolic blood pressure, HOMA-IR, fasting serum insulin. Odds ratio for HOMA-IR against the elevated ALT (>or=40 mg/dl) was 1.061 (95% confidence interval, 1.020-1.103, P=0.003). In girls, ALT was correlated with BMI, waist circumference, total cholesterol, triglyceride, glucose, systolic and diastolic blood pressure, HOMA-IR, fasting serum insulin. Odds ratio for HOMA-IR against the elevated ALT (>or=40 mg/dl) was 1.042 (95% confidence interval, 0.998-1.088, P=0.063). Among obese Korean children, insulin resistance and ALT, lipid profile, BMI, WC, blood pressure showed significant correlation. Especially, in boys, higher ALT is founded to be independently associated with insulin resistance.

Prevalence of metabolic syndrome, obesity and diabetes type 2 in cryptogenic cirrhosis

AIM: To evaluate the prevalence of metabolic syndrome (MS), obesity and type 2 diabetes mellitus (T2DM) in a group of Mexican Mestizo patients with cryptogenic cirrhosis (CC) and to compare this group with patients with cirrhosis secondary to other causes (disease controls).

METHODS: Patients with CC, diagnosed between January, 1990 and April, 2005, were included in a retrospective study. Patients with cirrhosis caused by chronic hepatitis C, alcohol abuse or autoimmune hepatitis (AIH) served as disease controls.

RESULTS: A total of 134 patients with CC were analyzed. Disease controls consisted of 81 patients with chronic hepatitis C, 33 with alcohol abuse and 20 with AIH. The median age of patients with CC was 57 years (range, 16-87); 83 (61.9%) patients were female; 53 (39.6%) were Child A, 65 (48.5%) Child B, and 16 (11.9%) were Child C cirrhosis. The prevalence of MS (29.1% vs 6%; P < 0.001), obesity (16.4% vs 8.2%; P = 0.04) and T2DM (40% vs 22.4%; P = 0.013) was higher in CC patients than in disease controls. There were no differences in sex, age or liver function tests between the two groups.

CONCLUSION: The prevalence of MS, obesity and T2DM were higher in patients with CC than in patients with cirrhosis secondary to others causes. Our findings support the hypothesis that non-alcoholic steatohepatitis (NASH) plays an under-recognized role in CC.

Relation between alanine aminotransferase concentrations and visceral fat accumulation among nondiabetic overweight Korean women

BACKGROUND

Alanine aminotransferase (ALT) is used as a surrogate marker for nonalcoholic fatty liver disease (NAFLD), which is frequently observed among obese subjects. Reported data were scanty about the relation between ALT concentrations and visceral fat accumulation measured by computed tomographic (CT) scanning in a large sample.

OBJECTIVE

We investigated the association between ALT concentrations and visceral fat accumulation measured by CT scanning, among nondiabetic overweight Korean women.

DESIGN

A cross-sectional study was performed in 903 nondiabetic overweight [body mass index (BMI; in kg/m(2)) > or = 25] Korean women aged 20-80 y. The area of abdominal visceral adipose tissue (VAT) was measured by CT scan. Anthropometric and cardiometabolic variables were measured.

RESULTS

Elevated ALT (> 40 IU/L) concentrations were found in 14.9% of the subjects. ALT concentrations were significantly correlated with all anthropometric and cardiometabolic variables after adjustment for age and alcohol consumption (P < 0.05). The adjusted odds ratios for elevated ALT concentrations according to the quartiles of VAT were 1.51 (95% CI: 0.83, 2.76), 3.16 (95% CI: 1.55, 6.49), and 15.15 (95% CI: 4.57, 50.00) in the second (76.9-102.6 cm(2)), the third (102.7-135.0 cm(2)), and the fourth (135.1-382.7 cm(2)) quartiles, respectively, compared with the first quartile (23.0-76.8 cm(2)) (P for trend < 0.001). In the multiple linear regression model, the VAT was significantly positively associated with ALT concentrations (standardized beta = 0.206, P < 0.001), whereas the regression coefficients of other anthropometric and cardiometabolic variables were not significant.

CONCLUSIONS

ALT concentrations have a strong association with visceral fat accumulation, and VAT is the main predictor of elevated ALT concentrations in the context of NAFLD among nondiabetic overweight Korean women.

Indications for liver transplantation

Patients should be considered for liver transplantation if they have evidence of fulminant hepatic failure, a life-threatening systemic complication of liver disease, or a liver-based metabolic defect or, more commonly, cirrhosis with complications such as hepatic encephalopathy, ascites, hepatocellular carcinoma, hepatorenal syndrome, or bleeding caused by portal hypertension. While the complications of cirrhosis can often be managed relatively effectively, they indicate a change in the natural history of the disease that should lead to consideration of liver transplantation. Referral to a liver transplant center is followed by a detailed medical evaluation to ensure that transplantation is technically feasible, medically appropriate, and in the best interest of both the patient and society. Patients approved for transplantation are placed on a national transplant list, although donor organs are allocated locally and regionally. Since 2002, priority for transplantation has been determined by the Model of End-Stage Liver Disease (MELD) score, which provides donor organs to listed patients with the highest estimated short-term mortality.

Nonalcoholic fatty liver disease: from clinical recognition to treatment

Nonalcoholic fatty liver disease (NAFLD) is probably the most common spectrum of metabolic liver disease in the world, encompassing simple steatosis to steatohepatitis, advanced fibrosis, cirrhosis and hepatocellular carcinoma. NAFLD affects a significant part of the general population worldwide. The existing correlation between obesity and NAFLD in combination with the increase in the frequency of obesity in the developed world implies that the incidence and severity of NAFLD will increase in the near future. Newer data support the idea that NAFLD constitutes the more important cause of cryptogenic cirrhosis of the liver and a ground for the development of hepatocellular carcinoma. Liver biopsy remains the most specific and sensitive method to differentiate NAFLD, providing important information on the long-term prognosis of the patients. The 'two hit' hypothesis constitutes the currently prevailing theory for the development of NAFLD and nonalcoholic steatohepatitis. The first 'hit' is purported to be the increase of free fatty acids in hepatocytes, which results in a decrease of beta-oxidation. The second step includes all mechanisms contributing to the development of necroinflammation and fibrosis. Currently, an effective treatment for patients with NAFLD does not exist. Improvement in liver histology remains the primary goal of any therapeutic approach in patients with NAFLD. Viewing NAFLD in the frame of the metabolic syndrome opens the possibility that both the onset of the disease and disease progression could be prevented by changes in lifestyle. Physical exercise and a low calorie diet in combination with the gradual loss of body weight represent the cornerstone for the management of NAFLD patients.

Current concepts in the evaluation of patients for liver transplantation

Candidates for liver transplantation undergo a thorough medical, surgical, psychosocial and financial evaluation prior to listing for transplantation. Prioritization for allocating livers is based upon the model for end-stage liver disease score and waiting-time mortality with the fundamental concept of giving organs to the sickest first. In the upcoming years the allocation system may be modified to include other factors associated with mortality, such as serum sodium, and may incorporate both pre- and post-transplant mortality. Strategies to expand the donor pool include utilizing livers from donors after cardiac death, split liver transplantation and living donor liver transplantation. Future challenges for liver transplantation will include the obesity epidemic and the prevention and treatment of recurrent disease, particularly hepatitis C.

Nonalcoholic fatty liver disease as a complication of insulin resistance

Nonalcoholic fatty liver disease (NAFLD) refers to a spectrum of liver damage ranging from simple steatosis to nonalcoholic steatohepatitis, advanced fibrosis, and rarely, progression to cirrhosis. The pathogenesis of NAFLD is thought to be related to insulin resistance and oxidant stress. Truncal obesity, dyslipidema, hypertension, and hyperglycemia are strongly associated with NAFLD; therefore, management of NAFLD entails identification and treatment of metabolic risk factors, improving insulin sensitivity, and increasing antioxidant defenses in the liver. This article briefly summarizes advances in our understanding of the relationship between NAFLD and the insulin resistance (metabolic) syndrome, its prevalence, natural history, and treatment.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) refers to the presence of hepatic steatosis not associated with a significant intake of ethanol. Insulin resistance is central to the pathogenesis of NAFLD; thus obesity, diabetes, and the metabolic syndrome are frequently associated with the disease. Consequently, as these metabolic conditions emerge as major health problems in Western society, it is now recognized that NAFLD is the most common chronic liver condition in the Western world. NAFLD is generally asymptomatic, although a minority of patients may present with evidence of progressive liver injury with complications of cirrhosis, liver failure, and hepatocellular carcinoma. Despite being common and potentially serious, relatively little is known about the natural history or prognostic significance of NAFLD. Although diabetes, obesity, and age are recognized risk factors for advanced liver disease, other significant factors leading to progressive liver injury remain to be identified. The treatment of NAFLD focuses upon modifying metabolic risk factors. Insulin-sensitizing and hepatoprotective drugs have been subjected to study trials, but as yet, no agent has conclusively been demonstrated to prevent disease progression. Management is further complicated by the inability to predict which patients will develop liver-related morbidity and thus benefit from treatment.

Nonalcoholic fatty liver disease: from pathogenesis to patient care

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in Western countries. It encompasses a wide spectrum of liver lesions, from pure steatosis to end-stage liver disease with cirrhosis and hepatocellular carcinoma. Nonalcoholic steatohepatitis corresponds only to one stage of NAFLD. As NAFLD can be considered a liver manifestation of the metabolic syndrome, its prevalence is high in obese people and in patients who have type 2 diabetes-insulin resistance is one of the key elements of the pathogenesis of NAFLD. This disease is often asymptomatic in the absence of decompensated cirrhosis, but should be suspected in patients with elevated aminotransferase levels or radiological evidence of a fatty liver or hepatomegaly. Liver fibrosis is associated with age over 50 years, obesity, diabetes and high triglyceride levels. Liver biopsy is the only way to assess the histologic features of necrotic inflammation and fibrosis that define nonalcoholic steatohepatitis and to determine its probable prognosis. The prognosis is good for pure steatosis, whereas the presence of necrotic inflammation is associated with a significant risk of progression to cirrhosis and, possibly, hepatocellular carcinoma. Lifestyle changes, such as dietary modifications and exercise, are recommended. To date, there have been very few randomized, placebo-controlled trials of drug treatments for NAFLD.

NASH and the risk of cirrhosis and hepatocellular carcinoma in type 2 diabetes

The risk of chronic liver disease and liver-related mortality is increased in patients with type 2 diabetes mellitus. Several cohort studies have suggested a metabolic pathway from nonalcoholic fatty liver, nonalcoholic steatohepatitis, cryptogenic cirrhosis, and eventually hepatocellular carcinoma. Although cardiovascular risk remains the major cause for excess mortality in type 2 diabetes mellitus, the risk of progressive liver disease should no longer be underscored.

Liver transplantation for metabolic liver diseases

Liver transplantation has become an accepted treatment for several metabolic liver diseases. With advances in organ transplantation and immunosuppressive strategies, survival rates following liver transplantation are generally excellent. When the primary metabolic defect is hepatic in origin, liver transplantation not only replaces the dysfunctional organ but also cures the underlying metabolic defect. For conditions in which the primary metabolic defect is extrahepatic, liver transplantation is usually performed for hepatic complications, although disease recurrence may occur. This article reviews common metabolic liver diseases treated with liver transplantation in the adult population.

Recurrence of nonviral diseases

As long-term graft survival and mortality after liver transplantation improve, recognition that allografts may be affected by the same disease process that resulted in the failure of the liver is of both clinical and academic importance. Recipients need to be counseled about recurrence and potential impact on graft function and graft survival; clinicians need to be aware of the potential of recurrence to interpret the clinical, laboratory, radiologic, and histologic findings and alter management. Understanding which conditions recur in the allograft and factors associated with recurrence may shed light on pathogenesis. This article discusses the recurrence of nonviral diseases after liver transplantation, diagnosis, and management.

Abnormal lipid and glucose metabolism in obesity: implications for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease represents a spectrum of histopathologic abnormalities, the prevalence of which may be as high as 24% of the population of the United States. Nonalcoholic fatty liver disease will play a major role in the science and practice of gastroenterology in the near future. The fundamental derangement in nonalcoholic fatty liver disease is insulin resistance, a key component of the metabolic syndrome, which includes type 2 diabetes mellitus, hypertriglyceridemia, essential hypertension, low circulating high-density lipoprotein, and obesity. The natural history of fatty liver disease is not always benign, and causality for cirrhosis and chronic liver disease is well-founded in the literature. Treatment strategies are limited and, at present, are primarily focused on weight loss and use of insulin sensitizing agents, including the thiazolidenediones. Recent data clearly implicate hepatic insulin resistance as a culprit in accumulation of free fatty acids as triglycerides in hepatocytes. Hepatic insulin resistance is clearly exacerbated by systemic insulin resistance and impaired handling by skeletal muscle and adipose tissue of both glucose and free fatty acids. The key consequence of hepatic insulin resistance, impaired hepatocyte insulin signal transduction, results in adverse cellular and molecular changes exacerbating hepatocyte triglyceride storage. Cytokines secreted by white adipose tissue, adipokines, have emerged as key players in glucose and fat metabolism previously thought controlled largely by insulin. Modulation of adipokines may aid in further understanding of the pathophysiology and treatment of nonalcoholic fatty liver disease.

Prevalence of nonalcoholic fatty liver disease in women with polycystic ovary syndrome

BACKGROUND & AIMS

Insulin resistance has been implicated in the pathogenesis of both nonalcoholic fatty liver disease (NAFLD) and polycystic ovary syndrome (PCOS). We hypothesized that NAFLD would be common in both obese and nonobese women with PCOS. The aim of this study was to estimate the prevalence of and identify associated factors for hepatic steatosis in women with PCOS.

METHODS

This is a retrospective study of 88 consecutive premenopausal women with PCOS. Clinical history, height, weight, and laboratory values were obtained. Fasting measurements of serum glucose and insulin were used to calculate homeostasis model assessment of insulin resistance (HOMA-IR). Abdominal ultrasonography was used to determine the presence and severity of hepatic steatosis.

RESULTS

Of the 88 women (median age, 31.4 years), 48 (55%) had steatosis; 15 (39%) of them were lean women. The presence of steatosis was associated with a greater body mass index (BMI) (P = .005) and HOMA-IR (P = .033), a lower fasting high-density lipoprotein (P = .003), and a greater prevalence of impaired fasting glucose, impaired glucose tolerance, and diabetes mellitus (P = .013). Only 7 (15%) subjects with hepatic steatosis had abnormal liver chemistries.

CONCLUSIONS

Fatty liver was identified in 55% of subjects with PCOS, nearly 40% of whom were lean women. High BMI and insulin resistance appeared to be important associated factors. Early recognition of NAFLD in this group of young patients is warranted, and further investigation including liver biopsy might be indicated.

Nonalcoholic Fatty liver disease and obesity

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized medical condition that may progress to hepatic cirrhosis with liver failure. The pathologic picture resembles that of alcohol-induced liver injury, but it occurs in patients who do not abuse alcohol. NAFLD is more common among patients with evidence of insulin resistance. NAFLD refers to a wide spectrum of liver damage, ranging from simple steatosis to steatohepatitis, fibrosis, and cirrhosis. The clinical implications of NAFLD are derived mostly from its common occurrence in the general population, specifically in obese individuals, and its potential to progress to cirrhosis and liver failure. It is difficult to propose a treatment strategy for NAFLD because its pathogenesis is poorly understood; however, the most commonly associated clinical features of obesity, diabetes mellitus, lipid disorders, and hypertension deserve therapeutic interventions independent of NAFLD. It is also not known if and how treatment of these other conditions affects the natural history of NAFLD, particularly in the long term.

Hepatocellular carcinoma in patients with nonalcoholic fatty liver disease: helical CT and MR imaging findings with clinical-pathologic comparison

PURPOSE

To retrospectively evaluate the clinical, pathologic, and helical computed tomographic (CT) and magnetic resonance (MR) imaging findings of hepatocellular carcinoma (HCC) in patients with nonalcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

Institutional review board approval was obtained for this study; the need for patient informed consent was waived. Clinical, pathologic, and imaging findings were retrospectively evaluated in 22 men (mean age, 64.5 years) with HCC and NAFLD. Helical CT and MR images were reviewed for morphologic features such as tumor size, margins, necrosis, and degree of enhancement.

RESULTS

Obesity, diabetes, and hypertension were common findings and were observed in 12 (55%), 14 (64%), and 13 (59%) of the 22 patients, respectively. The serum alpha-fetoprotein level was elevated in eight patients (36%). All patients had pathologic evidence of NAFLD. HCC was well-differentiated in seven patients, moderately differentiated in 11, and poorly differentiated in four. Large tumors (mean diameter, 8.4 cm) were depicted at CT and/or MR imaging in all patients. Twenty-one patients had a solitary or dominant mass. At imaging, tumor margins were well defined in 17 patients, with a smooth surface in 17, and there was evidence of a tumor capsule in 15. Necrosis was depicted in 16 patients. There was no evidence of calcifications, central scar, fat, or abdominal lymphadenopathy. CT was performed in 20 patients. HCC was hypoattenuating on unenhanced CT scans in 14 patients, heterogeneously hyperattenuating in the arterial phase in 20, and hypoattenuating in the portal phase in 14. MR imaging was performed in 16 patients. HCC was hyperintense compared with liver parenchyma at T2-weighted MR imaging in all 16 patients, hypointense at T1-weighted imaging in 14, heterogeneously hyperintense at arterial phase T1-weighted imaging in 16, and hypointense at portal phase T1-weighted imaging in 14.

CONCLUSION

HCC in patients with NAFLD is more likely to manifest as a large solitary or dominant mass characterized by smooth and possibly encapsulated margins, necrosis, and hypervascularity.

Epidemiology and natural history of NAFLD and NASH

Understanding of the epidemiology and natural history of non-alcoholic fatty liver disease (NAFLD) has increased; it is the most common form of chronic liver disease in the Western world and increasing in importance in other parts of the world. Prevalence is expected to increase as obesity and diabetes epidemics evolve. The natural history of NAFLD depends on the histologic subtype. Those who have simple hepatic steatosis or nonspecific inflammation generally have a benign long-term prognosis, whereas non-alcoholic steatohepatitis (NASH) can progress to cirrhosis. NASH-related cirrhosis may have a similar prognosis as cirrhosis from other causes, leading to liver failure or hepatocellular carcinoma.

Non-alcoholic steatohepatitis and cancer

Hepatocellular carcinoma (HCC) is part of the natural history of non-alcoholic steatohepatitis (NASH). A significant proportion of people who have cryptogenic cirrhosis develop HCC. NASH-related cirrhosis carries a substantial risk for early HCC development. Diagnosis of HCC often is made at first referral; the tumor usually is large with multiple localizations. Patients who have obesity or diabetes are at risk for HCC and a variety of cancers. Given the epidemic of obesity and diabetes, the incidence of NASH-related HCC is expected to increase. In addition to developing new diagnostic tools and pharmacologic therapies, efforts should be directed at preventing non-alcoholic fatty liver disease.

Probiotics for non-alcoholic fatty liver disease and/or steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease comprises a spectrum of diseases ranging from simple steatosis to non-alcoholic steatohepatitis, fibrosis, and cirrhosis. Probiotics have been proposed as a treatment option because of their modulating effect on the gut flora that could influence the gut-liver axis.

OBJECTIVES

To evaluate the beneficial and harmful effects of probiotics for non-alcoholic fatty liver disease and/or steatohepatitis.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (July 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2006), MEDLINE (1966 to May 2006), and EMBASE (1980 to May 2006). No language restrictions were applied.

SELECTION CRITERIA

Randomised clinical trials evaluating probiotic treatment in any dose, duration, and route of administration versus no intervention, placebo, or other interventions in patients with non-alcoholic fatty liver disease. The diagnosis was made by history of minimal or no alcohol intake, imaging techniques showing hepatic steatosis and/or histological evidence of hepatic damage, and by exclusion of other causes of hepatic steatosis.

DATA COLLECTION AND ANALYSIS

We had planned to extract data in duplicate and analyse results by intention-to-treat.

MAIN RESULTS

No randomised clinical trials were identified. Preliminary data from two pilot non-randomised studies suggest that probiotics may be well tolerated, may improve conventional liver function tests, and may decrease markers of lipid peroxidation.

AUTHORS' CONCLUSIONS

The lack of randomised clinical trials makes it impossible to support or refute probiotics for patients with non-alcoholic fatty liver disease and non-alcoholic steatohepatitis.

Antioxidant supplements for non-alcoholic fatty liver disease and/or steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is characterised by fatty deposition in the hepatocytes of patients with minimal or no alcohol intake and without other known cause. NAFLD includes a wide spectrum of histologic abnormalities ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), or even cirrhosis. Antioxidant supplements, therefore, could potentially protect cellular structures against oxidative stress and the resulting lipid peroxidation.

OBJECTIVES

To systematically evaluate the beneficial and harmful effects of antioxidant supplements versus no intervention, placebo, or other interventions for patients with NAFLD or NASH.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (June 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2006), MEDLINE (1966 to June 2006), EMBASE (1980 to June 2006), and the Chinese Biomedical Database (1978 to June 2006). No language restrictions were applied.

SELECTION CRITERIA

Randomised clinical trials evaluating any antioxidant supplements versus no intervention, placebo, or other interventions in patients with NAFLD or NASH. Our inclusion criteria for NAFLD or NASH were based on history of minimal or no alcohol intake, imaging techniques showing hepatic steatosis, and/or histological evidence of hepatic damage (including simple steatosis, fatty infiltration plus nonspecific inflammation, steatohepatitis, fibrosis, and cirrhosis), and by exclusion of other causes of hepatic steatosis.

DATA COLLECTION AND ANALYSIS

We extracted data from the identified trials and contacted authors. We used a random-effects model and fixed-effect model with the significant level set at P = 0.05. We evaluated the methodological quality of the randomised trials by looking at how the generation of allocation sequence, allocation concealment, blinding, and follow-up were performed. We made our analyses following the intention-to-treat method by imputing missing data.

MAIN RESULTS

We identified six trials: two were regarded of high methodological quality and four of low methodological quality. None of the trials reported any deaths. Treatment with antioxidant supplements showed a significant, though not clinically relevant, amelioration of aspartate aminotransferase levels, but not of alanine aminotransferase levels, as compared to placebo or other interventions. Gamma-glutamyl-transpeptidase was decreased, albeit not significantly, in the treatment arm. Radiological and histological data were too limited to draw any definite conclusions on the effectiveness of these agents. Adverse events were non-specific and of no major clinical relevance.

AUTHORS' CONCLUSIONS

There is insufficient data to either support or refute the use of antioxidant supplements for patients with NAFLD. It may be advisable to carry out large prospective randomised clinical trials on this topic.

Drugs improving insulin resistance for non-alcoholic fatty liver disease and/or non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver, which may progress to non-alcoholic steatohepatitis (NASH) and cirrhosis. It is suspected in persons with elevated aminotransferase levels and features of insulin resistance (or metabolic) syndrome. The pathogenesis of NAFLD is not clear and there is no universal treatment.

OBJECTIVES

To assess beneficial and harmful effects of drugs improving insulin resistance for NAFLD and/or NASH.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and The Chinese Biomedical Database until February 2006.

SELECTION CRITERIA

We included randomised clinical trials assessing the effects of drugs improving insulin resistance for patients with NAFLD or NASH.

DATA COLLECTION AND ANALYSIS

We evaluated the methodological quality of the randomised clinical trials by the generation of the allocation section, allocation concealment, and follow-up. Two independent observers extracted data from each trial. Dichotomous outcomes were reported as odds ratio (OR) with 95% confidence interval (CI).

MAIN RESULTS

Only three randomised clinical trials could be included. Two of the trials had unclear allocation concealment. None was blinded regarding outcome assessment. In two trials, metformin was associated with significantly higher normalization of serum alanine aminotransferase (OR fixed 2.83, 95% CI 1.27 to 6.31 versus diet and OR fixed 7.75, 95% CI 2.37 to 25.35 versus vitamin E) and improvement of liver echographic response (OR fixed 5.25, 95% CI 1.09 to 25.21). An improvement of fatty infiltration was observed in a limited number of patients undergoing liver biopsy. In the single pioglitazone trial, a statistically significant improvement of NASH histology was demonstrated.

AUTHORS' CONCLUSIONS

At present, there is insufficient data to either support or refute the use of drugs improving insulin resistance for patients with NAFLD, although current limited information suggests a favourable role of drugs improving insulin resistance. It is advisable to carry out large randomised trials on this topic employing clinically relevant outcome measures and adequate methodology, including blinded outcome assessment.

Leptin, superoxide dismutase, and weight loss: initial leptin predicts weight loss

OBJECTIVE

Our goal was to study how plasma leptin concentration, superoxide dismutase (SOD) activity, and weight loss are related in obese adults.

RESEARCH METHODS AND PROCEDURES

Serum leptin concentration, SOD activities, general biochemical data, and body composition measurements were obtained for 62 overweight and obese subjects before and after an 8-week body weight reduction (BWR) regimen. The subjects were on dietary control, performed moderate aerobic and strength training exercises, and attended educational lectures.

RESULTS

The measurement results indicated that the following criteria were significantly reduced: body weight [84.4 +/- 17.0 vs. 79.3 +/- 16.1 (standard error) kg, p < 0.001]; BMI (31.5 +/- 4.3 vs. 29.4 +/- 4.2 kg/m(2), p < 0.001), and fat mass (33.3 +/- 10.0 vs. 29.8 +/- 10.4 kg, p < 0.001). Plasma leptin levels also significantly decreased from 31.5 +/- 17.6 to 26.5 +/- 17.2 ng/mL (p < 0.001). Additionally, SOD activity was significantly increased from 261.4 +/- 66.0 to 302.7 +/- 30.9 U/mL (p < 0.001). Based on linear regression analysis results, a 3.78- to 8.13-kg reduction in weight can be expected after the 8-week BWR regimen when initial leptin concentration was 5 to 30 ng/mL.

DISCUSSION

We found that an 8-week exercise and diet program was effective in reducing weight and fat mass and, notably, had further beneficial effects on leptin resistance and SOD activity. Additionally, this study demonstrated that initial plasma leptin concentration may be used as a predictor for weight loss outcome.

[Epidemiology and natural history of primary nonalcoholic fatty liver disease]

The clinical impact of nonalcoholic fatty liver disease depends on its prevalence and natural history. The prevalence in the adult population is estimated to be about 23% and is on the increase. Thus, it has become the most common cause of persistent elevated liver enzymes, chronic liver disease, and cryptogenic cirrhosis in developed countries. The increasing prevalence of nonalcoholic fatty liver disease, which is approaching epidemic proportions, is parallel to that of other disorders associated with insulin resistance, especially obesity and type 2 diabetes mellitus. This entity occurs in men and women equally and in all age groups. The natural history is poorly defined mainly due to the scarcity of histologic follow-up studies. Although steatosis alone has a more benign clinical course, steatohepatitis is a progressive fibrotic disease, in which cirrhosis and liver-related death occur in a similar way to other causes of chronic liver diseases. Progression seems to be mainly dependent on the severity of histological damage at diagnosis, but age older than 40 years, obesity, and type 2 diabetes have also been associated with an increased risk of liver fibrosis and progression to cirrhosis.

Race and comorbid factors predict nonalcoholic fatty liver disease histopathology in severely obese patients

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is a common and potentially serious form of chronic liver disease. Although NAFLD is known to be associated with obesity and some comorbid conditions, less is known about the severity of NAFLD among different racial groups.

METHODS

We prospectively studied 237 consecutive morbidly obese patients presenting for bariatric surgery. All patients underwent intraoperative liver biopsy and chart review. After excluding subjects who reported alcohol use (n = 37) or who had missing biopsy data (n = 11), 189 patients were available for analysis. Clinical and laboratory associations with each of the histological components of NAFLD were assessed using multiple logistic regression analysis.

RESULTS

The mean age was 43.1 years, 84% were female, and 13% were African American. It was found that 88% had steatosis, including 35% with moderate to severe steatosis (> 33% of hepatocytes involved). Of these patients, 67% had inflammation, 46% had fibrosis, and 45% met Brunt's criteria for NASH. Compared with Caucasians and after adjustment, African Americans had significantly lower odds of severe hepatic pathology, with adjusted odds ratios of 0.1 (P = .02) for the presence of moderate or severe steatosis, 0.2 for inflammation (P = .006), 0.3 for fibrosis (P = .05), and 0.2 for NASH (P = .02). In addition, participants with one or more features of the metabolic syndrome (ie, diabetes, hypertension, or dyslipidemia) or elevated aminotransferase levels had significantly higher odds of severe hepatic histopathology.

CONCLUSION

Among obese patients presenting for bariatric surgery, NAFLD is more common in Caucasians, patients with features of the metabolic syndrome, and those with elevated aminotransferase levels.

Research on the protection effect of pioglitazone for non-alcoholic fatty liver disease (NAFLD) in rats

OBJECTIVE

The prevalence of non-alcoholic fatty liver disease (NAFLD) has markedly increased. Insulin resistance has been implicated in the pathogenesis of NAFLD. This study was aimed at observing the relationship between insulin resistance and NAFLD, and evaluating the role of pioglitazone (PGZ) acting as insulin-sensitizing agents in the prevention and treatment of rat fatty liver induced by high fat feeding.

METHODS

The rats were separated randomly into 6 groups: model group I were fed high fat diet for 8 weeks, PGZ prevention group were given PGZ 4 mg/(kg.d) simultaneously, while control group I were fed normal food for 8 weeks; model group II were fed high fat diet for 16 weeks, PGZ treatment group were given PGZ 4 mg/(kg.d) orally simultaneous with high fat diet for 8 weeks after high fat feeding for 8 weeks, control group II were fed normal food for 16 weeks. The rats were sacrificed after 8 weeks and 16 weeks respectively. Liver weight, body weight, serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), tumor necrosis factor alpha (TNF-alpha), fasting blood glucose (FBG), fasting plasma insulin (FINS), HOMA (homeostasis model assessment) insulin resistance index (HOMA-IR), and the liver histology of rats of all groups were assayed.

RESULTS

After 8 weeks, the liver in model group I showed typical steatosis, accompanied with mild to moderate lobular inflammatory cell infiltration, liver indexes and serum levels of ALT, AST, ALP, TNF-alpha were significantly increased (P<0.05) compared with control group I. Whereas, the degree of hepatic injury was attenuated in PGZ prevention group, liver indexes and serum levels of ALT, ALP were significantly decreased (P<0.05) compared with model group I. After 16 weeks, notable steatosis, and lobular inflammation were observed in model group II rat liver, while the degree of hepatic injury was attenuated in the PGZ treatment group. Liver index, serum levels of ALT, AST, ALP, FINS and HOMA-IR were significantly increased (P<0.05) in model group II compared with control group II. Whereas, in PGZ treatment group, serum levels of AST and FINS showed decreasing tendency, liver indexes, serum levels of ALT, ALP, TNF-alpha and HOMA-IR were significantly decreased compared with model group II.

CONCLUSION

Insulin resistance plays a role in the pathogenesis of NAFLD in rats. Pioglitazone can attenuate insulin resistance and biochemical and histological injury in high fat-induced fatty liver in rats.

Breath biomarkers and non-alcoholic fatty liver disease: preliminary observations

Breath biomarkers have the potential to offer information that is similar to conventional clinical tests or they are entirely unique. Preliminary data support the use of breath biomarkers in the study of liver disease, in particular non-alcoholic fatty liver disease (NAFLD). It was evaluated whether breath ethanol, ethane, sulfur compounds and acetone would be associated with hepatic histopathology amongst morbidly obese patients presenting for bariatric surgery. Breath samples were collected during a preoperative visit and compared with liver biopsies obtained during the surgery. A Student's two-tailed t-test was used to compare differences between the two groups. Linear regression was used to analyse associations between the concentrations of breath molecules and independent predictor variables. It was found that breath ethanol, ethane and acetone can be useful biomarkers in patients with NAFLD. In particular, breath ethanol can be associated with hepatic steatosis, and breath acetone can be associated with non-alcoholic steatohepatitis.

Favored T helper 1 response in a mouse model of hepatosteatosis is associated with enhanced T cell-mediated hepatitis

Steatohepatitis enhances the severity of liver injury caused by acute inflammation. The purpose of this study was to test the hypothesis that fatty liver due to chronic choline-deficient diet exacerbates concanavalin A (ConA)-induced liver hepatitis, which is predominantly facilitated by T cells. Male C57BL/6 mice were fed either control choline-sufficient diet (CSD) or choline-deficient diet (CDD) for 6 weeks before ConA administration. Mice were sacrificed 3, 9, and 24 hours after ConA injection. Liver injury measured by aspartate aminotransferase (AST), alanine aminotransferase (ALT), pathology, and terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) staining was minimal in mice fed either diet before ConA exposure. However, ConA-induced liver injury was significantly greater in CDD-fed mice compared with control-fed mice. Liver cytokines were assessed by quantitative real-time polymerase chain reaction (PCR). The expression of T helper (Th) 1 cytokines tumor necrosis factor alpha (TNF-alpha), interleukin 12 (IL-12), and interferon gamma (IFN-gamma) were dramatically elevated after ConA in CDD-fed mice compared with control-fed mice. CDD also enhanced ConA-induced STAT4 activation, but not STAT6. Notably, regulators of T-cell differentiation were strongly shifted toward a predominant Th1 profile. T-bet, regulator of the Th1 response, was up-regulated in CDD-fed mice, whereas Th2 regulator GATA-3 was significantly suppressed in CDD-fed mice after ConA. Moreover, the expression of suppressor of cytokine signaling (SOCS)-1, SOCS-3, and repressor of GATA-3 (ROG) favored a predominant Th1 cytokine response in CDD-fed mice. In conclusion, these data support the hypothesis that hepatosteatosis caused by CDD is associated with more severe ConA-induced hepatitis due to a predominant shift toward Th1 response.

A pilot study of atorvastatin treatment in dyslipemid, non-alcoholic fatty liver patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of liver injury. Currently, there are no proven effective therapies available. Atorvastatin is a new 3-hydroxy-3-metylglutaryl coenzyme A reductase inhibitor that reduces lipid serum levels.

AIM

To evaluate the effectiveness and safety of atorvastatin in dyslipemid, non-alcoholic fatty liver patients.

PATIENTS AND METHODS

We prospectively enrolled 25 patients with NAFLD; 22 of them completed the study. Body mass index, serum lipids, liver function tests and liver density assessed by echography were measured at baseline and after 1, 3, 6, 9 and 12 months of treatment. Normalization of transaminases and/or improvement in liver density were treatment end points. Patients received atorvastatin (10-80 mg/daily) according to basal serum choleresterol levels; additionally, they were given standard weight-loss counselling and encouraged to follow a low fat diet.

RESULTS

All 22 patients (14 men, mean age 47 +/- 10 years) had high cholesterol levels at baseline and 11 (44%) also presented high trygliceride levels. After 6 months of treatment, eight patients (36.3%) presented normal transaminase levels. The remaining patients continued treatment for 12 months when 20% of patients presented with normal transaminase levels, while the other patients showed a 10% reduction in basal levels. Mean cholesterol levels were 268.5 +/- 44.2 and 186.8 +/- 14.4 mg/dL before and after treatment, respectively (P < 0.05). The mean body mass index was 27.4 +/- 3.1 at baseline and 26.3 +/- 2.8 kg/cm2 at the end of treatment (P > 0.05). No side effects were reported.

CONCLUSIONS

Serum aminotransferase and lipid levels were reduced significantly in all patients with atorvastatin treatment. Therapy with atorvastatin in NAFLD patients with hyperlipidemia was found to be both effective and safe.

Cryptogenic cirrhosis in the region where obesity is not prevalent

AIM: Recent studies have demonstrated that obesity is the common feature of cryptogenic cirrhosis (CC) and non-alcoholic steatohepatitis. However, there is little information on CC in the region where obesity is not prevalent.

METHODS: The clinical features, and the liver-related morbidity and mortality of CC were analyzed in Japan where the prevalence of obesity is low. Among 652 cirrhotic patients, we identified 29 patients (4.4%) with CC. Of these, 24 CC patients who were followed up for more than 6 months were compared in a case-control study with age-, sex-, and Child-Pugh score-matched controls having cirrhosis of viral etiology.

RESULTS: Obesity (BMI≥25 kg/m²), diabetes mellitus, and hypertriglyceridemia were more frequent, and the visceral fat area was larger in the CC patients than in the controls. The indices of insulin resistance were higher and the serum aminotransferase levels were lower in the CC patients than in the controls. Logistic regression analysis identified the elevated hemoglobin A1c, BMI ≥ 25 kg/m², and normal aminotransferase levels as independent predictors of CC. Kaplan-Meier analysis demonstrated lower occurrence of hepatocellular carcinoma and higher survival rate in the CC than in the controls in contrast to the similar cumulative probability of liver-related morbidity between those groups.

CONCLUSION: CC more frequently presents with the clinical features suggestive of non-alcoholic steatohepatitis compared with controls even in the region where obesity is not prevalent. The lower occurrence of hepatocellular carcinoma and higher survival rate may indicate an indolent clinical course in CC as compared with viral cirrhosis.

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.

Similarities and differences in outcomes of cirrhosis due to nonalcoholic steatohepatitis and hepatitis C

The objective of this study was to prospectively define outcomes of cirrhosis due to nonalcoholic steatohepatitis (NASH) and compare them with those associated with hepatitis C virus (HCV) infection. We compared 152 patients with cirrhosis due to NASH with 150 matched patients with cirrhosis due to HCV. Over 10 years, 29/152 patients with cirrhosis due to NASH died compared with 44/150 patients with HCV (P < .04). This was mainly due to the lower mortality rate in patients with Child class A cirrhosis due to NASH versus HCV (3/74 vs. 15/75; P < .004). There were no significant across-group differences in mortality in patients with Child class B or C cirrhosis. Sepsis was the most common cause of death in both groups; patients with NASH had a higher cardiac mortality (8/152 vs. 1/150; P < .03). Patients with Child class A cirrhosis due to NASH also had a significantly lower risk of decompensation, defined by a 2-point increase in Child-Turcotte-Pugh score (P < .007). Cirrhosis due to NASH was associated with a lower rate of development of ascites (14/101 vs. 40/97 patients at risk; P < .006). NASH also had a significantly lower risk of development of hepatocellular carcinoma (10/149 vs. 25/147 patients at risk; P < .01). In conclusion, compensated cirrhosis due to NASH is associated with a lower mortality rate compared with that due to HCV. It is also associated with a lower rate of development of ascites, hyperbilirubinemia, and hepatocellular carcinoma. However, cardiovascular mortality is greater in patients with NASH.

Hepatocellular carcinoma with silent and cirrhotic non-alcoholic steatohepatitis, accompanying ectopic liver tissue attached to gallbladder

A 70-year-old man had been obese since youth. He had been treated for hypertension and diabetes mellitus. An abdominal ultrasound showed a mass in the liver. He was admitted to St Marianna University School of Medicine Hospital for further evaluation. There was no history of alcohol use, and hepatitis viral markers and autoantibodies were all negative. Several imaging studies showed overt hepatocellular carcinoma (HCC). Transcatheter arterial embolization was performed, followed by surgical resection. Histopathological examination revealed moderately differentiated HCC. The non-tumor areas had pseudolobules in a diffuse pattern similar to alcoholic cirrhosis. The histological findings in the ectopic liver tissue attached to the gallbladder, which was also resected during surgery, were that there was no cirrhosis, but fine fibrosis with inflammatory cell infiltration of sinusoids. These findings were consistent with non-alcoholic steatohepatitis (NASH). There was probably a progression of similar findings that had developed into cirrhosis. These findings confirmed a diagnosis of HCC, cirrhosis, and underlying NASH in this patient. The present case is important for investigation of the development into cirrhosis and carcinogenesis of NASH. The present case demonstrates the importance of evaluating obese patients with fatty liver for underlying NASH and ongoing follow up for development of cirrhosis and HCC.

Mouse models in non-alcoholic fatty liver disease and steatohepatitis research

Non-alcoholic fatty liver disease (NAFLD) represents a histological spectrum of liver disease associated with obesity, diabetes and insulin resistance that extends from isolated steatosis to steatohepatitis and cirrhosis. As well as being a potential cause of progressive liver disease in its own right, steatosis has been shown to be an important cofactor in the pathogenesis of many other liver diseases. Animal models of NAFLD may be divided into two broad categories: those caused by genetic mutation and those with an acquired phenotype produced by dietary or pharmacological manipulation. The literature contains numerous different mouse models that exhibit histological evidence of hepatic steatosis or, more variably, steatohepatitis; however, few replicate the entire human phenotype. The genetic leptin-deficient (ob/ob) or leptin-resistant (db/db) mouse and the dietary methionine/choline-deficient model are used in the majority of published research. More recently, targeted gene disruption and the use of supra-nutritional diets to induce NAFLD have gained greater prominence as researchers have attempted to bridge the phenotype gap between the available models and the human disease. Using the physiological processes that underlie the pathogenesis and progression of NAFLD as a framework, we review the literature describing currently available mouse models of NAFLD, highlight the strengths and weaknesses of established models and describe the key findings that have furthered the understanding of disease pathogenesis.

Exploration of global gene expression in human liver steatosis by high-density oligonucleotide microarray

Understanding the molecular mechanisms underlying fatty liver disease (FLD) in humans is of major importance. We used high-density oligonucleotide microarrays (22.3 K) to assess the mechanisms responsible for the development of human liver steatosis. We compared global gene expression in normal (n=9) and steatotic (n=9) livers without histological signs of inflammation or fibrosis. A total of 34 additional human samples including normal (n=11), steatosis (n=11), HCV-related steatosis (n=4) or steatohepatitis associated with alcohol consumption (n=4) or obesity (n=4) were used for immunohistochemistry or quantitative real-time PCR studies. With unsupervised classification (no gene selection), all steatotic liver samples clustered together. Using step-down maxT multiple testing procedure for controlling the Family-Wise Error-Rate at level 5%, 110 cDNAs (100 over- and 10 underexpressed) were found to be differentially expressed in steatotic and normal livers. Of them were genes involved in mitochondrial phosphorylative and oxidative metabolism. The mean ratio of mitochondrial DNA to nuclear DNA content was higher in liver steatosis compared to normal liver biopsies (1.12+/-0.14 vs 0.67+/-0.10; P=0.01). An increased expression of genes involved in inflammation (IL-1R family, TGFB) was also observed and confirmed by quantitative RT-PCR or immunochemistry. In steatohepatitis, an increase of the protein expression of mitochondrial antigens, IL-1R1, IGF2 and TGFB1 was also observed, interleukin 1 receptor being always strongly expressed in steatohepatitis linked to alcohol or obesity. In conclusion, mitochondrial alterations play a major role in the development of steatosis per se. Activation of inflammatory pathways is present at a very early stage of steatosis, even if no morphological sign of inflammation is observed.

Non-alcoholic fatty liver disease and the metabolic syndrome: Effects of weight loss and a review of popular diets. Are low carbohydrate diets the answer?

Non-alcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of fat-induced liver injury, ranging from relatively benign steatosis to cirrhosis and liver failure. The presence of obesity and insulin resistance is strongly associated with non-alcoholic fatty liver and confers on it a greater risk of histologically advanced disease. There is a growing concern in the medical profession as the prevalence of this disease continues to rise in parallel with the rise in obesity and the metabolic syndrome. Treatment options are limited and dietary weight loss is often advised. Low fat diets are difficult to adhere to and recent studies have shown the potential of low carbohydrate diets for weight loss and improving insulin resistance. Thus far, no study has evaluated the effect of low carbohydrate diets on NAFLD. Future studies will be required to address this question and others with regards to the nutritional adequacy and long-term side effects of these diets.

Nonalcoholic steatohepatitis and the metabolic syndrome

Relatively recently, the liver has been recognized as a major target of injury in patients with insulin resistance or the metabolic syndrome. Insulin resistance is associated with fat accumulation in the liver, a condition called nonalcoholic fatty liver disease (NAFLD). Excess fat in the liver is not a benign condition. Some patients with NAFLD develop necroinflammatory changes in the liver called nonalcoholic steatohepatitis (NASH) and a fraction of those will develop cirrhosis. About 20% all adults have NAFLD and 2% to 3% of adults have NASH. Approximately 20% of patients with NASH are at risk for developing cirrhosis and subsequently dying from end-stage liver disease. The diagnosis of NASH requires a high index of suspicion, especially in obese patients over the age of 45 years who have diabetes, because these are the patients at greatest risk for developing cirrhosis. Treatment focuses on addressing the underlying insulin resistance with increased exercise and weight reduction.

When is diabetes mellitus a relative or absolute contraindication to liver transplantation?

1. Diabetes mellitus is common in patients with cirrhosis; patients with DM undergoing liver transplantation often have many other co-morbid illnesses including obesity, coronary artery disease (CAD), autonomic neuropathy, gastroparesis, and nephropathy. 2. Long-term survival of patients with diabetes mellitus (DM) is significantly lower and morbidity higher when compared to non-diabetics mainly because of cardiovascular complications, infections, and renal failure. 3. Obesity, CAD, and renal failure are confounding factors that result in poor patient survival. 4. Patients with DM should undergo careful cardiovascular diagnostic work up, including routine coronary arteriogram, and necessary interventions before liver transplantation. This is especially important in those over 50 years old, and in those with retinopathy, nephropathy, and neuropathy. 5. Patients with coronary artery disease that is not amenable to surgery or stents, and those with impaired left ventricular function, should not be considered for liver transplantation. Other relative or absolute contraindications are those with proteinura and renal failure who are not candidates for combined liver/kidney transplantation, those with severe gastroparesis, especially when it is associated with diabetic autonomic neuropathy, and those with two or more risk factors such as CAD, morbid obesity, and renal failure. 6. Future studies should focus on risk stratification of patients with DM undergoing liver transplantation and better interventions to reduce the risk of diabetic complications before and after liver transplantation.

Relation between elevated serum alanine aminotransferase and metabolic syndrome in Korean adolescents

BACKGROUND

Concern is growing about nonalcoholic fatty liver disease, not only because it is a common liver disorder but also because it is one of the leading causes of chronic liver disease. Unexplained elevations in aminotransferase concentrations have been strongly associated with adiposity and thus may represent nonalcoholic fatty liver disease.

OBJECTIVE

We investigated the relation between nonviral or nonalcoholic elevations in alanine aminotransferase (ALT) and the metabolic syndrome in Korean adolescents.

DESIGN

Data were obtained from 1594 subjects aged 10-19 y from the Korean National Health and Nutrition Examination Survey 1998, a cross-sectional health survey of a nationally representative sample of noninstitutionalized civilian South Koreans. Body mass index, waist circumference, blood pressure, fasting glucose, lipid profiles, and serum ALT were measured.

RESULTS

The prevalence of elevated ALT (> 40 U/L) was 3.6% in boys and 2.8% in girls. The prevalence of metabolic syndrome was 3.3% in both boys and girls. The components of the metabolic syndrome were significantly worse in the group with elevated ALT concentrations than in the group with normal ALT concentrations. The odds ratios (95% CIs) for elevated ALT were 6.6 (3.7, 11.8), 2.3 (1.2, 4.6), and 3.0 (1.6, 5.8) in the adolescents with abdominal obesity, high triacylglycerol concentrations, and low HDL-cholesterol concentrations, respectively. The odds ratios for elevated ALT were 1.5 (0.7, 3.1), 2.6 (1.1, 6.2), and 6.2 (2.3, 16.8) in the adolescents with 1, 2, and > or = 3 risk factors (metabolic syndrome), respectively.

CONCLUSION

The metabolic syndrome was strongly associated with elevated ALT concentrations in Korean adolescents, and this association existed in a graded fashion across the number of metabolic components.

Approach to the diagnosis and treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease in the United States. It describes several clinicopathologic entities from simple hepatic steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. This article describes the epidemiology, clinical features, natural history, and pathogenesis of NAFLD.

Hepatic fat fraction: MR imaging for quantitative measurement and display--early experience

The institutional review board approved this HIPAA-compliant study. After all five patients with nonalcoholic fatty liver disease signed a consent, they underwent magnetic resonance (MR) imaging for hepatic fat quantification. The purpose of this study was to develop a fast and accurate method to acquire and display quantitative maps of the percentage of hepatic fat. In-phase and out-of-phase gradient-echo MR imaging was performed with dual flip angles (70 degrees, 20 degrees) to resolve ambiguity of the dominant constituent. T2* corrections were also estimated and applied to generate color-coded maps of the estimated percentage of hepatic fat. MR imaging results were compared with biopsy results in two of five patients, and the technique was validated qualitatively and quantitatively with a water-oil phantom. Results of the phantom study confirmed that the dual-flip angle algorithm can be used to correctly identify the dominant constituent, allowing depiction of 0%-100% of fat content. The estimated liver fat fraction was comparable to quantitative fat measurements at biopsy in both patients (MR imaging, 18.3% +/- 2.8 [standard deviation] and 28.6% +/- 2.4, vs quantitative histopathologic analysis, 11.2% and 28.5%, respectively).

SUPPLEMENTAL MATERIAL

radiology.rsnajnls.org/cgi/content/full/2373041639/DC1