Nonalcoholic fatty liver disease and nonalcoholic steatohepatitis in Japan

Clinical differences between alcoholic liver disease and nonalcoholic fatty liver disease

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are serious health problems worldwide. These two diseases have similar pathological spectra, ranging from simple hepatic steatosis to steatohepatitis, liver cirrhosis, and hepatocellular carcinoma. Although most subjects with excessive alcohol or food intake experience simple hepatic steatosis, a small percentage of individuals will develop progressive liver disease. Notably, both ALD and NAFLD are frequently accompanied by extrahepatic complications, including cardiovascular disease and malignancy. The survival of patients with ALD and NAFLD depends on various disease-associated conditions. This review delineates the clinical characteristics and outcomes of patients with ALD and NAFLD by comparing their epidemiology, the factors associated with disease susceptibility and progression, and the predictors and characteristics of outcomes. A comprehensive understanding of the characteristics and outcomes of ALD and NAFLD is imperative in the management of these chronic liver diseases.

Nationwide study of 4741 patients with non-B non-C hepatocellular carcinoma with special reference to the therapeutic impact

OBJECTIVE

To examine the prognostic factors and outcomes after several types of treatments in patients with hepatocellular carcinoma (HCC) negative for hepatitis B surface antigen and hepatitis C antibody, so-called "non-B non-C HCC" using the data of a nationwide survey.

BACKGROUND

The proportion of non-B non-C HCC is rapidly increasing in Japan.

METHODS

A total of 4741 patients with non-B non-C HCC, who underwent hepatic resection (HR, n = 2872), radiofrequency ablation (RFA, n = 432), and transcatheter arterial chemoembolization (TACE, n = 1437) as the initial treatment, were enrolled in this study. The exclusion criteria included extrahepatic metastases and/or Child-Pugh C. Significant prognostic variables determined by a univariate analysis were subjected to a multivariate analysis using a Cox proportional hazard regression model.

RESULTS

The degree of liver damage in the HR group was significantly lower than that in the RFA and TACE groups. The HR and TACE groups had significantly more advanced HCC than the RFA group. The 5-year survival rates after HR, RFA, and TACE were 66%, 49%, and 32%, respectively. Stratifying the survival rates, according to the TNM stage and the Japan Integrated Staging (JIS) score, showed the HR group to have a significantly better prognosis than the RFA group in the stage II and in the JIS scores "1" and "2." The multivariate analysis showed 12 independent prognostic factors. HR offers significant prognostic advantages over TACE and RFA.

CONCLUSIONS

The findings of this large prospective cohort study indicated that HR may be recommended, especially in patients with TNM stage II and JIS scores "1" and "2" of non-B non-C HCC.

Association of polymorphisms in GCKR and TRIB1 with nonalcoholic fatty liver disease and metabolic syndrome traits

In several genome-wide association studies, nonalcoholic fatty liver disease and alanine aminotransferase susceptibility variants have been identified in several genes, including LYPLAL1, ZP4, GCKR, HSD17B13, PALLD, PPP1R3B, FDFT1, TRIB1, COL13A1, CPN1, ERLIN1, CWF19L1, EFCAB4B, PZP, and NCAN. To investigate the relationship between these genes and nonalcoholic fatty liver disease in the Japanese population, we genotyped 540 patients and 1012 control subjects for 18 variations. We performed logistic regression analyses to characterize the association between the tested variations and nonalcoholic fatty liver disease. Metabolic syndrome and histological traits were also analyzed by linear regression. We also examined GCKR rs780094, TRIB1 rs2954021, and PNPLA3 rs738409 for epistatic effects. The A-allele of rs780094 in GCKR (P = 0.0024) and the A-allele of rs2954021 TRIB1 (P = 4.5×10⁻⁵) were significantly associated with nonalcoholic fatty liver disease. GCKR rs780094 was also associated with decreased plasma glucose, and increased triglycerides in the patient and control groups. GCKR rs780094 was also associated with an increased ratio of visceral to subcutaneous fat area in the patients with nonalcoholic fatty liver disease. Variations in GCKR, TRIB1, and PNPLA3 independently influenced nonalcoholic fatty liver disease and had no epistatic effects. Our data suggest variations in GCKR and TRIB1 are involved in the development of nonalcoholic fatty liver disease.

Clinical usefulness of non-protein respiratory quotient measurement in non-alcoholic fatty liver disease

AIM

Little is known about the effects of non-alcoholic fatty liver disease (NAFLD) on energy metabolism, although this disease is associated with metabolic syndrome. We measured non-protein respiratory quotient (npRQ) using indirect calorimetry, which reflects glucose oxidation, and compared this value with histological disease severity in NAFLD patients.

METHODS

Subjects were 32 patients who were diagnosed with NAFLD histopathologically. Subjects underwent body composition analysis and indirect calorimetry, and npRQ was calculated. An oral glucose tolerance test was performed, and plasma glucose area under the curve (AUC glucose) was calculated.

RESULTS

There were no differences in body mass index, body fat percentage or visceral fat area among fibrosis stage groups. As fibrosis progressed, npRQ significantly decreased (stage 0, 0.895 ± 0.068; stage 1, 0.869 ± 0.067; stage 2, 0.808 ± 0.046; stage 3, 0.798 ± 0.026; P < 0.005). Glucose intolerance worsened and insulin resistance increased with fibrosis stage. npRQ was negatively correlated with AUC glucose (R = -0.6308, P < 0.001), Homeostasis Model of Assessment - Insulin Resistance (R = -0.5045, P < 0.005), fasting glucose (R = -0.4585, P < 0.01) and insulin levels (R = -0.4431, P < 0.05), suggesting that decreased npRQ may reflect impaired glucose tolerance due to insulin resistance, which was associated with fibrosis progression. Estimation of fibrosis stage using npRQ was as accurate as several previously established scoring systems using receiver-operator curve analysis.

CONCLUSION

npRQ was significantly decreased in patients with advanced NAFLD. Our data suggest that measurement of npRQ is useful for the estimation of disease severity in NAFLD patients.

Obesity and gastrointestinal liver disorders in Japan

In Japan, the prevalence of obesity in adult men has increased since the 1970s, while that in adult women has not changed. The prevalence of obesity in 5-, 8-, 11-, and 14-year-old boys and girls increased from the late 1980s to late 1990 s and has decreased since 2000, while that in 17-year-old girls increased in 2002, similar to that for boys, but has since decreased. In 2009, 33.3% of adult men and 25.0% of adult women were obese, and 8-10% of children (age, 5-17 years) were obese. The prevalence of visceral obesity in adults was 50.8% of men and 18.0% of women. Obesity, especially visceral obesity, affects insulin resistance and increases metabolic diseases (diabetes mellitus, dyslipidemia, hypertension, cardiovascular disease, and non-alcoholic fatty liver disease [NAFLD]) and various cancers. In Japan, with a body mass index (BMI) of 23-25 as the reference category, the hazard ratio of total mortality is 1.36 for a BMI of 30-40 in men and 1.37 with a BMI of 30-40 in women. The frequency of patients with NAFLD has gradually increased in proportion to the increase in the population with obesity. From recent studies in Japan, the number of NAFLD patients is estimated to be 10 million, and around 2 million are considered to have non-alcoholic steatohepatitis. Dietary and behavioral modification is effective for body weight loss and for improvement of obesity-related gastrointestinal liver diseases. If necessary, bariatric surgery is useful for obesity treatment.

Clinical and histological determinants of nonalcoholic steatohepatitis and advanced fibrosis in elderly patients

The characteristics of nonalcoholic fatty liver disease (NAFLD) in elderly patients are unknown. Therefore, we aimed to examine the differences between elderly and nonelderly patients with NAFLD and to identify determinants of nonalcoholic steatohepatitis (NASH) and advanced fibrosis (bridging fibrosis or cirrhosis) in elderly patients. This is a cross-sectional analysis of adult participants who were prospectively enrolled in the NASH Clinical Research Network studies. Participants were included based on availability of the centrally reviewed liver histology data within 1 year of enrollment, resulting in 61 elderly (age ≥65 years) and 735 nonelderly (18-64 years) participants. The main outcomes were the presence of NASH and advanced fibrosis. Compared to nonelderly patients with NAFLD, elderly patients had a higher prevalence of NASH (56% versus 72%, P = 0.02), and advanced fibrosis (25% versus 44%, P = 0.002). Compared to nonelderly patients with NASH, elderly patients with NASH had higher rates of advanced fibrosis (35% versus 52%, P = 0.03), as well as other features of severe liver disease including the presence of ballooning degeneration, acidophil bodies, megamitochondria, and Mallory-Denk bodies (P ≤ 0.05 for each). In multiple logistic regression analyses, independent determinants of NASH in elderly patients included higher aspartate aminotransferase (AST) (odds ratio [OR] = 1.12, P = 0.007) and lower platelets (OR = 0.98, P = 0.02); and independent determinants of advanced fibrosis included higher AST (OR = 1.08, P = 0.007), lower alanine aminotransferase value (OR = 0.91, P = 0.002), and an increased odds of having low high-density lipoprotein (OR = 8.35, P = 0.02).

CONCLUSION

Elderly patients are more likely to have NASH and advanced fibrosis than nonelderly patients with NAFLD. Liver biopsy may be considered in elderly patients and treatment should be initiated in those with NASH and advanced fibrosis.

Utility of controlled attenuation parameter measurement for assessing liver steatosis in Japanese patients with chronic liver diseases

AIM

Steatosis is a common histological feature of chronic liver disease, especially alcoholic and non-alcoholic fatty liver disease, as well as chronic hepatitis C. A recent study showed that evaluating the controlled attenuation parameter (CAP) with transient elastography was an efficient way of non-invasively determining the severity of hepatic steatosis. The objective of this study was to prospectively evaluate the utility of CAP for diagnosing steatosis in patients with chronic liver disease.

METHODS

One hundred and fifty-five consecutive patients with suspected chronic liver disease underwent steatosis diagnosis using CAP, blood sample analyses, computed tomography for assessing the liver/spleen ratio and liver biopsy. Steatosis was graded according to the percentage of fat-containing hepatocytes: S0, less than 5%; S1, 5-33%; S2, 34-66%; and S3: more than 66%.

RESULTS

The CAP was significantly correlated with steatosis grade, and there were significant differences between the CAP value of the S0 patients and those of the patients with other grades of steatosis. S0 and S1-3 hepatic steatosis were considered to represent mild and significant steatosis, respectively. The CAP values of the patients with mild and significant steatosis were significantly different (P < 0.0001). The area under the receiver-operator curve (AUROC) value of the CAP for diagnosing significant steatosis was 0.878 (95% confidence interval, 0.818-0.939), and the optimal CAP cut-off value for detecting significant steatosis was 232.5 db/m. In multivariate analysis, the CAP (P = 0.0002) and the liver to spleen ratio (P = 0.004) were found to be significantly associated with significant steatosis.

CONCLUSION

The CAP is a promising tool for rapidly and non-invasively diagnosing steatosis.

Immunological mechanisms in the pathophysiology of non-alcoholic steatohepatitis

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

The future liver of the Asia pacific: fatter and firmer from more fructose and fortune?

The Asia Pacific region is the most diverse and the most populous region in the world. Recent socioeconomic changes have resulted in an emerging epidemic of non-communicable diseases such as type 2 diabetes and nonalcoholic fatty liver disease. The prevalence of nonalcoholic fatty liver disease in Asian Pacific countries now approximates that seen in Western countries. This increase is fueled by rising obesity, partly due to adoption of Western style diets and exposure to compounds such as high fructose corn syrup that are not included in traditional diets. Furthermore, South Asian populations may be more genetically susceptible via the inheritance of polymorphisms in apolipoprotein 3 that increase insulin resistance and nonalcoholic fatty liver disease. Importantly, there remains a substantial lack of data on the incidence and natural history of nonalcoholic steatohepatitis and subsequent complications such as hepatocellular carcinoma in Asian Pacific populations. This information gap prevents estimation of current and future disease burden and impedes efforts to lobby health policymakers to improve public health measures, as given the size of Asian Pacific populations, prevention rather than treatment of non-communicable diseases remains key. This review article addresses these issues and highlights research priorities for nonalcoholic fatty liver disease within the Asia Pacific region.

NAFLD in Asia--as common and important as in the West

NAFLD--regarded as a consequence of the modern sedentary, food-abundant lifestyle prevalent in the West--was recorded in Japan nearly 50 years ago and its changing epidemiology during the past three decades is well-documented. NAFLD, and its pathologically more severe form NASH, occur in genetically susceptible people who are over-nourished. Asian people are particularly susceptible, partly owing to body composition differences in fat and muscle. Community prevalence ranges between 20% (China), 27% (Hong Kong), and 15-45% (South Asia, South-East Asia, Korea, Japan and Taiwan). This Review presents emerging data on genetic polymorphisms that predispose Asian people to NAFLD, NASH and cirrhosis, and discusses the clinical and pathological outcomes of these disorders. NAFLD is unlikely to be less severe in Asians than in other populations, but the associated obesity and diabetes pandemics have occurred more recently in Asia than in Europe and the USA, and occur with reduced degrees of adiposity. Cases of cryptogenic cirrhosis and hepatocellular carcinoma have also been attributed to NAFLD. Public health efforts to curb over-nutrition and insulin resistance are needed to prevent and/or reverse NAFLD, as well as its adverse health outcomes of type 2 diabetes, cardiovascular events, cirrhosis and liver cancer.

Fatty liver Shionogi-ob/ob mouse: A new candidate for a non-alcoholic steatohepatitis model

AIM

The fatty liver Shionogi (FLS) mouse develops hereditary fatty liver without obesity. The FLS-ob/ob mouse made by transferring the leptin(ob) gene demonstrates several metabolic disorders and marked fat deposition in the liver. The aim was to evaluate which mouse model, the FLS or FLS-ob/ob, is more useful for non-alcoholic steatohepatitis research.

METHODS

FLS (n = 40) and FLS-ob/ob (n = 40) mice were fed a standard diet for 12, 24, 36 and 48 weeks, and then killed. The degree of fat deposition, oxidative stress, fibrosis and apoptosis were analyzed in the liver. Hepatic mRNA expression of fibrogenic and pro-inflammatory cytokines was measured.

RESULTS

FLS mice developed hepatic steatosis and slight fibrosis without obesity between 12 and 48 weeks of age. Conversely, FLS-ob/ob mice developed severe steatosis at 12 weeks of age, and steatohepatitis with increased oxidative stress and advanced fibrosis between 24 and 36 weeks of age. At 48 weeks of age, some FLS-ob/ob but not FLS mice, progressed to cirrhosis. Transforming growth factor-β1, connective tissue growth factor and tumor necrosis factor-α mRNA expression levels were greater in FLS-ob/ob than FLS mice between 24 and 48 weeks of age. The number of apoptotic cells in the liver was greater at 12 weeks of age in FLS mice and at 48 weeks of age in FLS-ob/ob mice.

CONCLUSION

FLS-ob/ob mice developed more severe steatohepatitis with fibrosis than FLS mice, and had increased oxidative stress and apoptosis. These findings indicate that the FLS-ob/ob mouse is a more useful model for steatohepatitis research.

Interactive effects of smoking and glutathione S-transferase polymorphisms on the development of non-alcoholic fatty liver disease

Glutathione S-transferases (GSTs) protect cells against exogenous and endogenous oxidative stress. GST polymorphisms are associated with the development of cardiovascular disease (CVD) and diabetes mellitus (DM), especially in current-smokers. Non-alcoholic fatty liver disease (NAFLD) is a predictor of future CVD or DM, because oxidative stress contributes to their pathogenesis. This study investigated whether the combination of smoking status and GST genotypes could affect the risk for NAFLD. A cross-sectional analysis was conducted among 713 Japanese participants (458 males and 255 females) during a health screening program. The GSTM1 null, GSTT1 null, GSTP1 A/B or B/B and GSTA1 A/B or B/B genotypes were determined and deemed to be high-risk genotypes. The prevalence of NAFLD was 18.7%. Among never-smokers, carriers of one, and those of two or more high-risk GSTM1, GSTP1 or GSTA1 genotypes were at a higher risk for NAFLD than those who were not carriers [odds ratio (95% confidence interval): 2.6 (1.1-5.9) and 3.3 (1.3-8.1), respectively], and the risk was further increased among current-smokers [4.6 (1.6-13.0) and 5.4 (1.2-23.7), respectively]. This is the first report to show that the combination of current-smoking and harboring high-risk GSTM1, GSTP1 and/or GSTA1 genotypes is interactively associated with the risk of NAFLD.

Clinicopathological features of liver injury in patients with type 2 diabetes mellitus and comparative study of histologically proven nonalcoholic fatty liver diseases with or without type 2 diabetes mellitus

BACKGROUND

The Japan Society of Diabetes Mellitus reported that the leading cause of death in patients with diabetes mellitus (DM) was chronic liver disease; however, there are limited studies investigating the cause of liver injury in these patients. Our study aimed to clarify the clinicopathological features of liver injury and the characteristics of nonalcoholic fatty liver disease (NAFLD) in DM patients.

METHODS

In total, 5,642 DM patients and 365 histologically proven NAFLD patients were enrolled. Clinical and laboratory parameters and liver biopsy results were, respectively, recorded and analyzed for the two sets of patients.

RESULTS

Positivity rates for Hepatitis B surface antigens (HBsAg) and anti-hepatitis C virus antibodies (anti-HCV Ab) were 1.7 and 5.1 %, respectively. The proportion of drinkers consuming 20-59 g and ≥60 g alcohol daily was 14.9 and 4.3 %, respectively. The percentage of DM patients with elevated serum alanine aminotransferase (ALT) levels (≥31 IU/L) was 28.6 %. Alcohol consumption had no significant effect on serum ALT levels. Seventy-two percent of HBsAg-positive patients were serum hepatitis B virus (HBV)-DNA negative, whereas 10 % exhibited high levels of the same (>4.0 log copies/ml). Thirty-eight percent of anti-HCV Ab-positive patients were serum HCV-RNA negative. Among the NAFLD patients, the frequencies of NASH and advanced stage NASH were significantly higher in male DM patients than in male patients without DM.

CONCLUSIONS

Although HBsAg- and anti-HCV Ab-positivity rates were high in our Japanese DM patients, a majority of liver injuries could be associated with NAFLD/nonalcoholic steatohepatitis.

Independent association between low serum amylase and non-alcoholic fatty liver disease in asymptomatic adults: a cross-sectional observational study

OBJECTIVES

Low serum amylase (LSA) was reported to be associated with obesity, metabolic syndrome (MetS) and diabetes. However, it is unknown as to whether LSA is associated with non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of MetS and insulin resistance. Therefore, we performed a clinical epidemiological study to investigate this potential association.

DESIGN

A cross-sectional observational study with multivariate analysis.

SETTING

Subjects were recruited in a healthcare centre in Saitama, an eastern district of Japan, near Tokyo.

PARTICIPANTS

A total of 1475 asymptomatic adults aged 30-79 years who underwent detailed medical check-ups and who regularly consumed small amounts of alcohol (<20 g/day).

OUTCOME MEASURES

Serum amylase, cardiometabolic risk factors, NAFLD determined by ultrasound, MetS determined by Adult Treatment Panel-III criteria and diabetes were assessed.

RESULTS

The prevalence of NAFLD increased significantly from 22.5% to 42.4% (all grades) and from 9.2% to 24.0% (moderate or severe grade) from the highest to the lowest quartile of serum amylase. Multiple logistic regression analysis showed that, compared with the highest quartile of serum amylase, the lowest quartile of serum amylase was significantly associated with any-grade NAFLD and with moderate-to-severe NAFLD, even after adjusting for MetS or diabetes. The association between LSA and any-grade NAFLD disappeared after further adjustment for body mass index or waist circumference, whereas the association between LSA and moderate or severe NAFLD remained statistically significant (ORs (95%CI), 2.01 (1.07 to 3.78) and 2.06 (1.09 to 3.87), respectively, both p=0.01).

CONCLUSIONS

Our results suggest that LSA may be associated with moderate or severe NAFLD in asymptomatic adults independent of MetS, diabetes and obesity. These results warrant confirmation in further studies.

Etiology of liver cirrhosis in Brazil: chronic alcoholism and hepatitis viruses in liver cirrhosis diagnosed in the state of Espírito Santo

OBJECTIVES

To report the etiology of liver cirrhosis cases diagnosed at the University Hospital in Vitoria, Espirito Santo, Brazil.

METHODS

The medical charts of patients with liver cirrhosis who presented to the University Hospital in Vitoria were reviewed. Chronic alcoholism and the presence of hepatitis B or C infections (HBV and HCV, respectively) were pursued in all cases.

RESULTS

The sample consisted of 1,516 cases (male:female ratio 3.5:1, aged 53.2 ± 12.6 years). The following main etiological factors were observed: chronic alcoholism alone (39.7%), chronic alcoholism in association with HBV or HCV (16.1 %), HCV alone (14.5%) and in association with alcoholism (8.6%) (total, 23.1 %), and HBV alone (13.1%) and in association with alcoholism (7.5%, total 20.6%). The remaining etiologies included cryptogenic cases (9.8%) and other causes (6.0%). The mean patient age was lower and the male-to-female ratio was higher in the cirrhosis cases that were associated with alcoholism or HBV compared with other causes. Intravenous drug abuse and a history of surgery or blood transfusion were significantly associated with HCV infection. Hepatocellular carcinoma was present at the time of diagnosis in 15.4% of cases. Chronic alcoholism associated with HCV infection was significantly associated (p<0.001) with reduced age (at the time of cirrhosis diagnosis) and increased prevalence of hepatocellular carcinoma (p = 0.052).

CONCLUSION

Alcoholism, HCV and HBV are the main factors associated with liver cirrhosis in the state of Espirito Santo. Chronic alcoholism associated with HCV infection reduced the age of patients at the time of liver cirrhosis diagnosis.

Comparison of the relationships of alcoholic and nonalcoholic fatty liver with hypertension, diabetes mellitus, and dyslipidemia

We compared the relationships of alcoholic fatty liver and nonalcoholic fatty liver with hypertension, diabetes mellitus, and dyslipidemia. Using a nationwide Japanese survey, we collected data on subjects with biopsy-proven alcoholic fatty liver or nonalcoholic fatty liver. Multiple logistic regression analysis was performed to determine whether alcoholic fatty liver and nonalcoholic fatty liver are associated factors for these diseases. Data on 191 subjects (65, alcoholic fatty liver; 126, nonalcoholic fatty liver) were analyzed. Alcoholic fatty liver (odds ratio, 2.54; 95% confidence interval, 1.06–6.32; p = 0.040), age ≥55 years, and body mass index ≥25 kg/m² were correlated with hypertension, whereas nonalcoholic fatty liver (odds ratio, 2.32; 95% confidence interval, 1.08–5.20; p = 0.035) and serum γ-glutamyl transpeptidase levels ≥75 IU/l were correlated with dyslipidemia. Furthermore, we found that there were biological interactions between alcoholic fatty liver and body mass index ≥25 kg/m² in ≥55-year-old subjects (attributable proportion due to interaction, 0.68; 95% confidence interval, 0.19–1.17), as well as between alcoholic fatty liver and age ≥55 years in subjects with body mass index ≥25 kg/m² (attributable proportion due to interaction, 0.71; 95% confidence interval, 0.24–1.18). Alcoholic fatty liver was more strongly associated with hypertension than nonalcoholic fatty liver and nonalcoholic fatty liver was more strongly associated with dyslipidemia than alcoholic fatty liver. Moreover, alcoholic fatty liver, obesity, and older age may interact to influence hypertension status.

Prevalence and risk factors for non-alcoholic fatty liver disease in Asian people who are not obese

Fatty liver (hepatic steatosis) is prevalent in industrialized countries. It is typically linked to obesity, central obesity and the presence of metabolic syndrome. With the introduction of a Westernized lifestyle and the increasing frequency of obesity in the Asia-Pacific region, the prevalence of non-alcoholic fatty liver disease (NAFLD) has been increasing over the past two decades. The risk factors are similar to those in other ethnic populations; but it is important to adopt the regional (ethnic-specific) anthropometric criteria to define overweight, obesity (including central obesity) and metabolic syndrome. To be noted, even using strict ethnic-specific criteria, a high percentage (15-21%) of Asia-Pacific NAFLD subjects in some series have been found to be non-obese, i.e. to have a normal body mass index (BMI) (17.5-22.4 kg/m(2)) or to be overweight (BMI 22.5-24.9 kg/m(2)). Differential distribution of visceral adipose tissue, recent increase in body weight, intake of high cholesterol diet and genetic background are factors likely associated with the development of NAFLD in these non-obese (but often overweight) Asia-Pacific subjects. Furthermore, insulin resistance may be the underlying key mechanism. In addition, since NAFLD may be the hepatic manifestation of metabolic syndrome, the presence of NAFLD is a predictor of future type 2 diabetes, metabolic syndrome and cardiovascular disease. Therefore, interventions at the public health level are indicated to halt the trend of overweight as well as obesity in Asia-Pacific region, particularly among those with relevant family history. Since the pathophysiology of NAFLD is closely related to metabolic derangement, lifestyle modification remains the cornerstone of management.

Clinical and pathological progression of non-alcoholic steatohepatitis to hepatocellular carcinoma

AIM

  Non-alcoholic steatohepatitis (NASH) can progress to hepatocellular carcinoma (HCC). We aimed to examine the clinical and pathological course of how NASH progresses to HCC.

METHODS

  In this retrospective multicenter study conducted in Japan, we examined 19 patients (53% female), who had been previously diagnosed with histologically proven NASH and developed HCC during the follow-up period. The median age of the patients at the time of initial diagnosis of NASH was 65 years.

RESULTS

  NASH progressed to HCC after a median follow-up period of 3.8 years (range: 0.5-11.6 years). All patients had been identified as having HCC during screening, which included 12 patients assessed by ultrasound, four patients assessed with computerized tomography, two patients that underwent serum des-γ-carboxy prothrombin testing and one patient that underwent serum α-fetoprotein testing. The median diameter of HCC tumors was 1.8 cm (range: 0.8-3.0 cm). The majority of patients (n = 13; 68%) presented with only one HCC tumor. The stage of liver fibrosis was significantly more advanced at the time of diagnosis of HCC than at the time of initial diagnosis of NASH, whereas there were no significant differences in the degree of steatosis.

CONCLUSION

  Screening for HCC with imaging is necessary not only in NASH patients with advanced fibrosis, but also in those with less advanced forms of fibrosis, particularly if they are old men. Liver fibrosis progresses to a more advanced stage during the development of HCC in NASH patients.

Genetic polymorphisms of the human PNPLA3 gene are strongly associated with severity of non-alcoholic fatty liver disease in Japanese

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) includes a broad range of liver pathologies from simple steatosis to cirrhosis and fibrosis, in which a subtype accompanying hepatocyte degeneration and fibrosis is classified as nonalcoholic steatohepatitis (NASH). NASH accounts for approximately 10-30% of NAFLD and causes a higher frequency of liver-related death, and its progression of NASH has been considered to be complex involving multiple genetic factors interacting with the environment and lifestyle.

PRINCIPAL FINDINGS

To identify genetic factors related to NAFLD in the Japanese, we performed a genome-wide association study recruiting 529 histologically diagnosed NAFLD patients and 932 population controls. A significant association was observed for a cluster of SNPs in PNPLA3 on chromosome 22q13 with the strongest p-value of 1.4 × 10(-10) (OR = 1.66, 95%CI: 1.43-1.94) for rs738409. Rs738409 also showed the strongest association (p = 3.6 × 10(-6)) with the histological classifications proposed by Matteoni and colleagues based on the degree of inflammation, ballooning degeneration, fibrosis and Mallory-Denk body. In addition, there were marked differences in rs738409 genotype distributions between type4 subgroup corresponding to NASH and the other three subgroups (p = 4.8 × 10(-6), OR = 1.96, 95%CI: 1.47-2.62). Moreover, a subgroup analysis of NAFLD patients against controls showed a significant association of rs738409 with type4 (p = 1.7 × 10(-16), OR = 2.18, 95%CI: 1.81-2.63) whereas no association was obtained for type1 to type3 (p = 0.41). Rs738409 also showed strong associations with three clinical traits related to the prognosis of NAFLD, namely, levels of hyaluronic acid (p = 4.6 × 10(-4)), HbA1c (p = 0.0011) and iron deposition in the liver (p = 5.6 × 10(-4)).

CONCLUSIONS

With these results we clearly demonstrated that Matteoni type4 NAFLD is both a genetically and clinically different subset from the other spectrums of the disease and that the PNPLA3 gene is strongly associated with the progression of NASH in Japanese population.

Hepatic recruitment of macrophages promotes nonalcoholic steatohepatitis through CCR2

Inflammatory cell infiltration in the liver is a hallmark of nonalcoholic steatohepatitis (NASH). The chemokine-chemokine receptor interaction induces inflammatory cell recruitment. CC-chemokine receptor (CCR)2 is expressed on hepatic macrophages and hepatic stellate cells. This study aims to investigate the therapeutic potential of CCR2 to NASH. Twenty-two weeks on a choline-deficient amino acid-defined (CDAA) diet induced steatosis, inflammatory cell infiltration, and liver fibrosis with increased CCR2 and monocyte chemoattractant protein (MCP)-1 expression in the wild-type livers. The infiltrated macrophages expressed CD68, CCR2, and a marker of bone marrow-derived monocytes, Ly6C. CCR2(-/-) mice had less steatosis, inflammatory cell infiltration, and fibrosis, and hepatic macrophages expressing CD68 and Ly6C were decreased. Toll-like receptor (TLR)4(-/-), TLR9(-/-), and MyD88(-/-) mice had reduced hepatic macrophage infiltration with decreased MCP-1 and CCR2 expression because TLR signaling is a potent inducer of MCP-1. To assess the role of Kupffer cells at the onset of NASH, Kupffer cells were depleted by liposomal clodronate. The Kupffer cell depletion ameliorated steatohepatitis with a decrease in the MCP-1 expression and recruitment of Ly6C-expressing macrophages at the onset of NASH. Finally, to test the therapeutic potential of targeting CCR2, a CCR2 inhibitor was administered to mice on a CDAA diet. The pharmaceutical inhibition of CCR2 prevented infiltration of the Ly6C-positive macrophages, resulting in an inhibition of liver inflammation and fibrosis. We concluded that CCR2 and Kupffer cells contribute to the progression of NASH by recruiting bone marrow-derived monocytes.

Role of obesity and lipotoxicity in the development of nonalcoholic steatohepatitis: pathophysiology and clinical implications

As obesity reaches epidemic proportions, nonalcoholic fatty liver disease (NAFLD) is becoming a frequent cause of patient referral to gastroenterologists. There is a close link between dysfunctional adipose tissue in NAFLD and common conditions such as metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. This review focuses on the pathophysiology of interactions between adipose tissue and target organs in obesity and the resulting clinical implications for the management of nonalcoholic steatohepatitis. The release of fatty acids from dysfunctional and insulin-resistant adipocytes results in lipotoxicity, caused by the accumulation of triglyceride-derived toxic metabolites in ectopic tissues (liver, muscle, pancreatic beta cells) and subsequent activation of inflammatory pathways, cellular dysfunction, and lipoapoptosis. The cross talk between dysfunctional adipocytes and the liver involves multiple cell populations, including macrophages and other immune cells, that in concert promote the development of lipotoxic liver disease, a term that more accurately describes the pathophysiology of nonalcoholic steatohepatitis. At the clinical level, adipose tissue insulin resistance contributes to type 2 diabetes mellitus and cardiovascular disease. Treatments that rescue the liver from lipotoxicity by restoring adipose tissue insulin sensitivity (eg, significant weight loss, exercise, thiazolidinediones) or preventing activation of inflammatory pathways and oxidative stress (ie, vitamin E, thiazolidinediones) hold promise in the treatment of NAFLD, although their long-term safety and efficacy remain to be established. Better understanding of pathways that link dysregulated adipose tissue, metabolic dysfunction, and liver lipotoxicity will result in improvements in the clinical management of these challenging patients.

NASH is an Inflammatory Disorder: Pathogenic, Prognostic and Therapeutic Implications

While non-alcoholic fatty liver disease (NAFLD) is highly prevalent (15% to 45%) in modern societies, only 10% to 25% of cases develop hepatic fibrosis leading to cirrhosis, end-stage liver disease or hepatocellular carcinoma. Apart from pre-existing fibrosis, the strongest predictor of fibrotic progression in NAFLD is steatohepatitis or non-alcoholic steatohepatitis (NASH). The critical features other than steatosis are hepatocellular degeneration (ballooning, Mallory hyaline) and mixed inflammatory cell infiltration. While much is understood about the relationship of steatosis to metabolic factors (over-nutrition, insulin resistance, hyperglycemia, metabolic syndrome, hypoadiponectinemia), less is known about inflammatory recruitment, despite its importance for the perpetuation of liver injury and fibrogenesis. In this review, we present evidence that liver inflammation has prognostic significance in NAFLD. We then consider the origins and components of liver inflammation in NASH. Hepatocytes injured by toxic lipid molecules (lipotoxicity) play a central role in the recruitment of innate immunity involving Toll-like receptors (TLRs), Kupffer cells (KCs), lymphocytes and neutrophils and possibly inflammasome. The key pro-inflammatory signaling pathways in NASH are nuclear factor-kappa B (NF-κB) and c-Jun N-terminal kinase (JNK). The downstream effectors include adhesion molecules, chemokines, cytokines and the activation of cell death pathways leading to apoptosis. The upstream activators of NF-κB and JNK are more contentious and may depend on the experimental model used. TLRs are strong contenders. It remains possible that inflammation in NASH originates outside the liver and in the gut microbiota that prime KC/TLR responses, inflamed adipose tissue and circulating inflammatory cells. We briefly review these mechanistic considerations and project their implications for the effective treatment of NASH.

Hepatocellular carcinoma in non-alcoholic steatohepatitis: Growing evidence of an epidemic?

The incidence of hepatocellular carcinoma in non-viral-related chronic liver disease has gradually increased in Japan. Obesity and diabetes mellitus type 2 have been established as a significant risk factor for hepatocellular carcinoma (HCC) by epidemiologic observations and experimental studies. The risks of these factors for HCC are likely conferred by two factors: the increased risk for development of non-alcoholic steatohepatitis (NASH) and the carcinogenic potential of themselves. Hepatocellular carcinoma in NASH is difficult to evaluate because histological diagnosis is required for diagnosis of NASH, which can lead selection bias. Furthermore, end-stage NASH is in effect "burned-out" NASH, for which the diagnosis of NASH cannot be made any more. At all events, previous studies on the etiology of Japanese HCC showed that non-alcoholic fatty liver disease accounts for 1-5% of all HCC (male predominant, median age 72 years). They have high prevalences of obesity and/or diabetes mellitus type 2 and 10-75% of the HCC arose from non-cirrhotic livers. HCC in NASH may be of multicentric origin, similar to HCC based on viral hepatitis. Regular screening for HCC is extremely important especially in cirrhotic NASH patients and recurrence should be warned. In western and Asian countries, the prevalence of non-alcoholic fatty liver disease in the general population is increasing dramatically. Therefore, there is an urgent need to elucidate pathogenesis and clinical features of HCC in NASH. In this review we summarize current concepts for HCC in NASH.

Association of genetic polymorphisms of glutathione-S-transferase genes (GSTT1, GSTM1, and GSTP1) and susceptibility to nonalcoholic fatty liver disease in Zahedan, Southeast Iran

Oxidative damage is thought to play a pivotal role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Glutathione-S-transferases (GSTs) are involved in cell protection against oxidative stress. We examined whether GSTM1, GSTT1, and GSTP1 polymorphisms are associated with NAFLD in a sample of the Iranian population. The current case-control study included 83 patients with NAFLD and 93 healthy subjects. The GSTM1 and GSTT1 polymorphisms were analyzed by multiplex polymerase chain reaction (PCR). The GSTP1 polymorphism was detected by tetra amplification refractory mutation system-PCR assay. The GSTM1-null genotype was significantly associated with the development of NAFLD (odds ratios [OR]=2.171, 95% confidence intervals [CI]=1.188-3.970, p=0.015). The GSTP1 Val allele was shown to be a risk factor for NAFLD (OR=1.739, 95% CI=1.089-2.777, p=0.024). The GSTT1 polymorphism was not significantly different between control and patient groups (p=0.221). This study showed that GSTM1 and GSTP1, but not GSTT1, genetic polymorphisms are associated with NAFLD in a sample of the Iranian population, and may be used to determine the risk of development of NAFLD.

Mechanisms and implications of age-related changes in the liver: nonalcoholic Fatty liver disease in the elderly

Nonalcoholic fatty liver disease (NAFLD) is hepatic steatosis associated with metabolic abnormalities such as overweight/central obesity, insulin resistance, type 2 diabetes (T2D), and dyslipidemia. NAFLD is becoming the most common liver disease in contemporary society, with the highest prevalence in those over 60 years. NAFLD pathology ranges from simple steatosis to a necroinflammatory fibrosing disorder called steatohepatitis (SH), the latter associated with high risk of developing cirrhosis, often occuring in the seventh to ninth decades of life. While the main health implications of NAFLD are increased risk of developing T2D, cardiovascular diseases, and common cancers, there is substantantially increased standardized mortality, and deaths from decompensated cirrhosis and hepatocellular carcinoma (HCC). Little is known about the interactive effects of ageing and NAFLD, with most studies focusing on the younger population. This paper summarises the epidemiology, pathogenesis, and clinical course of NAFLD, with particular attention to persons over age 60 years. An approach to the management of NASH and its complications in the elderly, will also be presented here.

Type 2 Diabetes Mellitus-Induced Hyperglycemia in Patients with NAFLD and Normal LFTs: Relationship to Lipid Profile, Oxidative Stress and Pro-Inflammatory Cytokines

Type 2 diabetes mellitus is associated with dyslipdemia, insulin resistance and non alcoholic fatty liver disease. The purpose of the current study was to assess whether type 2 diabetes mellitus-induced hyperglycemia has an effect on the lipid profile and release of oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests which may in turn lead to enhancing the pathogenicity of this liver disease. For this purpose, one hundred and five outpatients, matched in age and weight, were classified into two groups: the first group consisted of patients with non alcoholic fatty liver disease and the second group consisted of patients with non alcoholic fatty liver disease in conjunction with hyperglycemia due to the presence of type 2 diabetes mellitus. In all patients, lipid profile, oxidative stress, and inflammatory mediators were assessed by measuring serum concentrations of triglycerides, low density lipoprotein, hydrogen preroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6, respectively. In the studied population, it was found that the presence of type 2 diabetes mellitus-induced hyperglycemia significantly impaired lipid profile, and significantly enhanced the formation of hydrogen preroxide and malondialdehyde as well as significantly increased the release of tumor necrosis factor-alpha and interleukin-6 in the second group of patients. In addition, plasma glucose level showed significant positive correlation with hydrogen peroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6. From the previous results, it was concluded that the presence of type 2 diabetes mellitus-induced hyperglycemia results in significant increase in lipid profile, oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests. For this reason, further research studies may be essential to evaluate the benefit of adding suitable antioxidant and anti-inflammatory drugs to the treatment regimen for this group of patients. In addition, regular monitoring of blood glucose levels and liver function tests should be advised to this category of patients to reduce liver fat deposition and avoid the development of non alcoholic steatohepatitis, cirrhosis or liver cancer and their related complications.

Characteristics of patients with nonalcoholic steatohepatitis who develop hepatocellular carcinoma

BACKGROUND & AIMS

Nonalcoholic steatohepatitis (NASH) can progress to hepatocellular carcinoma (HCC). We aimed to characterize the clinical features of NASH patients with HCC.

METHODS

In a cross-sectional multicenter study in Japan, we examined 87 patients (median age, 72 years; 62% male) with histologically proven NASH who developed HCC. The clinical data were collected at the time HCC was diagnosed.

RESULTS

Obesity (body mass index ≥25 kg/m(2)), diabetes, dyslipidemia, and hypertension were present in 54 (62%), 51 (59%), 24 (28%), and 47 (55%) patients, respectively. In nontumor liver tissues, the degree of fibrosis was stage 1 in 10 patients (11%), stage 2 in 15 (17%), stage 3 in 18 (21%), and stage 4 (ie, liver cirrhosis) in 44 (51%). The prevalence of cirrhosis was significantly lower among male patients (21 of 54, 39%) compared with female patients (23 of 33, 70%) (P = .008).

CONCLUSIONS

Most patients with NASH who develop HCC are men; the patients have high rates of obesity, diabetes, and hypertension. Male patients appear to develop HCC at a less advanced stage of liver fibrosis than female patients.