Increase in the prevalence of fatty liver in Japan over the past 12 years: analysis of clinical background

Helicobacter pylori infection and liver diseases: Epidemiology and insights into pathogenesis

Both Helicobacter pylori (H. pylori) infection and liver diseases, including nonalcoholic fatty liver disease (NAFLD), viral hepatitis, and hepatocellular carcinoma (HCC), have high prevalences worldwide, and the relationship between H. pylori infection and liver disease has been discussed for many years. Although positive correlations between H. pylori and NAFLD have been identified in some clinical and experimental studies, negative correlations have also been obtained in high-quality clinical studies. Associations between H. pylori and the pathogenesis of chronic viral hepatitis, mainly disease progression with fibrosis, have also been suggested in some clinical studies. Concerning HCC, a possible role for H. pylori in hepatocarcinogenesis has been identified since H. pylori genes have frequently been detected in resected HCC specimens. However, no study has revealed the direct involvement of H. pylori in promoting the development of HCC. Although findings regarding the correlations between H. pylori and liver disease pathogenesis have been accumulating, the existing data do not completely lead to an unequivocal conclusion. Further high-quality clinical and experimental analyses are necessary to evaluate the efficacy of H. pylori eradication in ameliorating the histopathological changes observed in each liver disease.

Lean non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD), with its increasing prevalence and association with various co-morbidities, such as diabetes, cardiovascular disease and metabolic syndrome, is a growing concern. Previously thought to predominantly affect obese individuals, NAFLD has been shown to occur in non-obese subjects. This subset of individuals, known to have 'lean NAFLD' or 'non-obese NAFLD', is also growing increasingly prevalent. We summarize the clinical manifestations, pathophysiology and management of lean NAFLD in both adult and pediatric populations.

METHODS

Two reviewers performed an independent, formal review and analysis of the literature (PubMed and EMBASE search until April 2018).

RESULTS AND CONCLUSIONS

Patients with lean NAFLD share metabolic features of insulin resistance and dyslipidemia, similar to obese patients with NAFLD. Genetic predisposition, dietary and environmental factors may play a role in the pathogenesis of lean NAFLD. Genetic and metabolic conditions should be considered as well. Currently, there are no formal recommendations for the treatment of adult or pediatric lean NAFLD; however, lifestyle changes aimed at improving overall fitness are likely to have a favorable impact.

Fatty liver index predicts incident diabetes in a Japanese general population with and without impaired fasting glucose

AIM

Fatty liver is associated with the development of diabetes. However, to our knowledge, no study has examined the relationship between the fatty liver index (FLI), calculated scores of hepatic steatosis, and the development of diabetes among individuals without impaired fasting glucose (IFG). We aimed to examine whether FLI predicts the development of diabetes in individuals with and without IFG in a Japanese general population.

METHODS

We selected 1498 men and 2941 women who participated in Specific Health Checkups in Japan. We divided all participants into six groups according to tertiles of FLI (low, moderate, and high) and the presence or absence of IFG, by sex. We calculated hazard ratios for incident diabetes for each group using a Cox proportional hazard model, adjusting for potential confounders.

RESULTS

During a mean follow-up period of 3.0 years, 176 cases of diabetes in men and 320 cases in women were identified. Compared with the low FLI group without IFG, the high FLI group without IFG was significantly associated with incident diabetes in both men (hazard ratio, 1.90; 95% confidence interval, 1.08-3.36) and women (hazard ratio, 1.72; 95% confidence interval, 1.18-2.51). All IFG groups were significantly associated with incident diabetes regardless of FLI levels.

CONCLUSIONS

Our results showed that FLI is associated with the development of diabetes regardless of sex and the presence or absence of IFG, and that it may be a useful predictor of future risk of incident diabetes even in individuals without IFG.

Association of sugar sweetened beverages consumption with non-alcoholic fatty liver disease: a systematic review and meta-analysis

PURPOSE

The relationship between consumption of sugar sweetened beverages (SSB) and NAFLD has been reported in several epidemiological studies, but the results are inconsistent. The present systematic review and meta-analysis of observational studies was carried out to assess the relationship between sugar sweetened beverages consumption and NAFLD.

METHODS

Online databases were searched systematically through December, 2016 for studies investigating association between SSB consumption and NAFLD but limited to observational studies in human. Pooled odds ratio (OR) and 95% confidence intervals were calculated using Der-Simonian and Laird method while random effects meta-analysis was used, taking into account conceptual heterogeneity. Heterogeneity was assessed with the Cochran Q statistic and quantified with the I² statistic.

RESULTS

Of the 1015 identified articles, 42 were reviewed in depth and six studies (four cross-sectional, one case-control, and one cohort) met the criteria for inclusion in our systematic review with 6326 participants and 1361 cases of NAFLD in both men and women. Finally, four cross-sectional studies were included in the meta-analysis. Higher intake of SSBs (highest compared to lowest categories) was significantly associated with NAFLD, with a 40% increased Odds of NAFLD after adjusting for important potential confounders (pooled odds ratio 1.40; 95% CI 1.07, 1.82). There was no evidence for significant heterogeneity across studies [P = 0.226 (Q statistics), I² = 31.0%]. A significant positive association between SSB consumption and NAFLD was observed consistently in a sensitivity analysis [range of summary ORs 1.39-1.49]. There was no evidence of publication bias for the association between SSB and NAFLD.

CONCLUSIONS

This meta-analysis supports a positive significant association between higher consumption of SSB and NAFLD in both men and women. These findings strengthen the evidence that intake of SSBs should be limited to reduce fatty liver disease.

Estrogens and female liver health

Due to declining estrogen levels during menopause, NAFLD prevalence is higher in postmenopausal women compared to in premenopausal women or in men. Postmenopausal women are more susceptible to weight gain, fat redistribution and dyslipidemia, all major hallmarks of metabolic syndrome associated with increased NAFLD risk. Gut microbiota plays important roles in development of gastrointestinal tract, metabolism and immunity. Host-microbe interactions allows regulation of a wide range of pathways that affect healthy and diseased physiology. Recent advances in - omics technologies, such as microbiome, transcriptome and metabolome analysis, provided evidence that estrogens and intestinal microbiota (IM) can collectively influence obesity, inflammatory disease, diabetes, and cancers. By understanding underlying mechanisms of estrogens and microbiota crosstalk, we might design dietary and pharmacological interventions to alleviate the metabolic syndrome and NAFLD.

Cigarette smoking is a risk factor for the onset of fatty liver disease in nondrinkers: A longitudinal cohort study

Background

The effect of cigarette smoking on the onset of nonalcoholic fatty liver disease (NAFLD) is unclear, especially that associated with drinking small amounts of alcohol. We conducted a longitudinal study to investigate the relationship between cigarette smoking and NAFLD onset, which was stratified according to the amount of alcohol consumed.

Methods

We enrolled 7,905 Japanese subjects who had received annual health checkups more than twice between April 2003 and August 2013, 4,045 of whom met at least one of the following exclusion criteria and were excluded: (a) fatty liver at baseline; (b) hepatitis B or hepatitis C; (c) alcohol consumption (men: ≥210 g/wk; women: ≥140 g/wk); (d) change in alcohol drinking status between baseline and the study’s endpoint; (e) change in cigarette smoking habits between baseline and the study’s endpoint; or (f) current treatment with antidiabetic agents, antihypertensive agents, and/or lipid-lowering agents. The remaining 3,860 subjects (1,512 men, 2,348 women) were divided into two groups based on average alcohol consumption.

Results

After adjusting for the variables associated with metabolic disease, smoking was associated with fatty liver disease onset compared with nonsmokers in nondrinkers (adjusted hazard ratio = 1.988, 95% confidence interval 1.057–3.595; p = 0.034). No association was found between smoking and fatty liver disease onset in the low alcohol consumption group (men: <210 g alcohol/week; women: <140 g alcohol/week). The fatty liver disease incidence increased significantly among the nondrinkers as the number of cigarettes smoked increased (p = 0.001).

Conclusions

Cigarette smoking may be a significant risk factor associated with NAFLD onset in nondrinkers. These results may help clinicians to identify patients who are at a high risk of developing NAFLD and to prevent the progression of NAFLD by promoting earlier interventions that help people discontinue unhealthy lifestyle habits.

LiverSex Computational Model: Sexual Aspects in Hepatic Metabolism and Abnormalities

The liver is to date the best example of a sexually dimorphic non-reproductive organ. Over 1,000 genes are differentially expressed between sexes indicating that female and male livers are two metabolically distinct organs. The spectrum of liver diseases is broad and is usually prevalent in one or the other sex, with different contributing genetic and environmental factors. It is thus difficult to predict individual's disease outcomes and treatment options. Systems approaches including mathematical modeling can aid importantly in understanding the multifactorial liver disease etiology leading toward tailored diagnostics, prognostics and therapy. The currently established computational models of hepatic metabolism that have proven to be essential for understanding of non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) are limited to the description of gender-independent response or reflect solely the response of the males. Herein we present LiverSex, the first sex-based multi-tissue and multi-level liver metabolic computational model. The model was constructed based on in silico liver model SteatoNet and the object-oriented modeling. The crucial factor in adaptation of liver metabolism to the sex is the inclusion of estrogen and androgen receptor responses to respective hormones and the link to sex-differences in growth hormone release. The model was extensively validated on literature data and experimental data obtained from wild type C57BL/6 mice fed with regular chow and western diet. These experimental results show extensive sex-dependent changes and could not be reproduced in silico with the uniform model SteatoNet. LiverSex represents the first large-scale liver metabolic model, which allows a detailed insight into the sex-dependent complex liver pathologies, and how the genetic and environmental factors interact with the sex in disease appearance and progression. We used the model to identify the most important sex-dependent metabolic pathways, which are involved in accumulation of triglycerides representing initial steps of NAFLD. We identified PGC1A, PPARα, FXR, and LXR as regulatory factors that could become important in sex-dependent personalized treatment of NAFLD.

Combination of PNPLA3 and TLL1 polymorphism can predict advanced fibrosis in Japanese patients with nonalcoholic fatty liver disease

BACKGROUND

Hepatic fibrosis is an independent risk factor for mortality and liver-related events in patients with nonalcoholic fatty liver disease (NAFLD). PNPLA3 rs738409 has been associated with fibrosis in viral and non-viral hepatitis. TLL1 rs17047200 also has been associated with developing hepatocellular carcinoma probably via hepatic fibrogenesis. We estimated the impact of these genetic polymorphisms on hepatic fibrosis in Japanese patients with NAFLD.

METHODS

We analyzed the association between these genetic variants and the backgrounds of 817 individuals who received health checkups (health check cohort) from 2012 to 2014. Then, we investigated the relationship between genetic variants and liver histology in 258 consecutive patients with biopsy-proven NAFLD in Japan (NAFLD cohort) from 2012 to 2017 (UMIN000027399).

RESULTS

The prevalence of PNPLA3 CG/GG in the NAFLD cohort was higher than that in the health check cohort (p < 0.001). The prevalence of patients with advanced fibrosis (stages 3-4) was higher for PNPLA3 genotype CG/GG than CC (p = 0.048) and for TLL1 genotype AT/TT than AA (p = 0.044). The high-risk group which had at least two risk alleles of these variants was more likely to have advanced fibrosis (p = 0.004). Multivariate analysis identified body mass index [odds ratio (OR) 1.123, serum AST (OR 1.037, p = 0.004], serum albumin (OR 0.247, p = 0.032), and genetic high risk (OR 2.632, p = 0.026) as predictors of advanced fibrosis.

CONCLUSIONS

In Japanese patients with NAFLD, individuals with risk alleles of PNPLA3 and TLL1 may have a risk of advanced fibrosis.

Bile acid detoxifying enzymes limit susceptibility to liver fibrosis in female SHRSP5/Dmcr rats fed with a high-fat-cholesterol diet

During middle age, women are less susceptible to nonalcoholic steatohepatitis (NASH) than men. Thus, we investigated the underlying molecular mechanisms behind these sexual differences using an established rat model of NASH. Mature female and male stroke-prone spontaneously hypertensive 5/Dmcr rats were fed control or high-fat-cholesterol (HFC) diets for 2, 8, and 14 weeks. Although HFC-induced hepatic fibrosis was markedly less severe in females than in males, only minor gender differences were observed in expression levels of cytochrome P450 enzymes (CYP)7A1, CYP8B1 CYP27A1, and CYP7B1, and multidrug resistance-associated protein 3, and bile salt export pump, which are involved in fibrosis-related bile acid (BA) kinetics. However, the BA detoxification-related enzymes UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) 2A1, and the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), were strongly suppressed in HFC-fed males, and were only slightly changed in HFC-diet fed females. Expression levels of the farnesoid X receptor and its small heterodimer partner were similarly regulated in a gender-dependent fashion following HFC feeding. Hence, the pronounced female resistance to HFC-induced liver damage likely reflects sustained expression of the nuclear receptors CAR and PXR and the BA detoxification enzymes UGT and SULT.

Risk Factors for the Development of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis, Including Genetics

Nonalcoholic fatty liver disease is emerging as the most common cause of chronic liver disease worldwide. This trend is, in part, secondary, to the growing incidence of obesity, type 2 diabetes, and metabolic syndrome. Other risk factors include age, gender, race/ethnicity, genetic predisposition, and polycystic ovarian disease. With the introduction of genome-wide association studies, genetic mutations contributing to inherited susceptibility to steatosis have been identified, which hold keys to future improvement in diagnosis and management. This article expands on the aforementioned risk factors and summarizes the current available data on genetic and environmental factors associated with this common entity.

Involvement of Porphyromonas gingivalis in the progression of non-alcoholic fatty liver disease

BACKGROUND AND AIMS

The risk factors in the progression of nonalcoholic fatty liver disease (NAFLD) have not been fully clarified. Porphyromonas gingivalis (P.g) has been considered to be a confounding risk factor for systemic diseases. We aimed to evaluate the effect of P.g infection on risk of progression to NASH.

METHODS

(1) Serum IgG antibody titers against P.g fimbriae (fimA) in 200 biopsy-proven NAFLD patients were measured by ELISA and compared with histological findings. (2) C57BL/6J mice were fed a control diet (CD) or high-fat diet (HFD) with or without P.g-odontogenic infection and analyzed histologically. Mouse livers were analyzed using CE-TOFMS and LC-TOFMS.

RESULTS

(1) A significant correlation between fibrosis progression and antibody titers against P.g possessing fimA type 4 was identified (P = 0.0081). Multivariate analysis identified older age and type 4 P.g-positivity as risk factors for advanced fibrosis. (2) Fibrosis and steatosis were more severe in HFD P.g(+) mice compared with HFD P.g(-) mice. In metabolome analysis, fatty acid metabolism was significantly disrupted with HFD in P.g-infected mouse livers. Monounsaturated/saturated fatty acid ratios were significantly higher in the HFD P.g(+) group than in the HFD P.g(-) group (P < 0.05). Moreover, expression levels of SCD1 and ELOVL6 were significantly reduced.

CONCLUSIONS

These results suggest that P.g infection is an important risk factor for pathological progression in NAFLD. Increase in the monounsaturated/saturated fatty acid ratio may be an important change that facilitates progression of NAFLD.

Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention

NAFLD is one of the most important causes of liver disease worldwide and will probably emerge as the leading cause of end-stage liver disease in the coming decades, with the disease affecting both adults and children. The epidemiology and demographic characteristics of NAFLD vary worldwide, usually parallel to the prevalence of obesity, but a substantial proportion of patients are lean. The large number of patients with NAFLD with potential for progressive liver disease creates challenges for screening, as the diagnosis of NASH necessitates invasive liver biopsy. Furthermore, individuals with NAFLD have a high frequency of metabolic comorbidities and could place a growing strain on health-care systems from their need for management. While awaiting the development effective therapies, this disease warrants the attention of primary care physicians, specialists and health policy makers.

Developmental Origins of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Its prevalence is currently increasing not only in developed obese countries but also in developing countries. Recent findings from human cohorts and animal studies suggest that a nutritional imbalance in the early critical period is causatively associated with the incidence of NAFLD in later life. Based on the current theory of the developmental origins of health and disease (DOHaD), undernourishment and overnourishment in utero are both hypothesized to prime the predisposition for hepatic fat storage. Current knowledge on the developmental origins of NAFLD is introduced in this chapter.

The Fatty Liver Index: A Simple and Accurate Predictor of Colorectal Adenoma in an Average-Risk Population

BACKGROUND

Nonalcoholic fatty liver disease, the hepatic manifestation of metabolic syndrome, is associated with increased risk of colorectal adenoma, a precursor of colorectal cancer. Because nonalcoholic fatty liver disease and colorectal adenoma share many common risk factors of metabolic syndrome, the association between these 2 pathological findings has been investigated in multiple studies, but the results have been conflicting.

OBJECTIVE

The present study aimed to assess the relationship between the fatty liver index, a predictor of nonalcoholic fatty liver disease, and the prevalence of colorectal adenomas.

DESIGN

This is a retrospective observational study.

SETTINGS

This study was conducted at a single expert center.

PATIENTS

A total of 2976 consecutive subjects over 40 years of age undergoing routine checkups including abdominal ultrasonography and colonoscopy at Chung-Ang University Hospital Health Care Center were included.

MAIN OUTCOME MEASURES

The primary outcome measured was the prevalence of colorectal adenomas according to fatty liver index.

RESULTS

Among these subjects, 932 (31.3%) had colorectal adenoma, 691 (23.2%) had metabolic syndrome, and 1512 (50.8%) had fatty liver on ultrasonography. In multivariate analysis, fatty liver index ≥30 was associated with an increased risk of colorectal adenoma (OR, 1.269; 95% CI, 1.06-1.49; p = 0.008). The fatty liver index-high group (fatty liver index ≥30) had more colorectal adenomas and more advanced colorectal adenomas than the fatty liver index-low group (fatty liver index <30) (p < 0.001 and p = 0.042). The prevalence of colorectal adenomas increased with increasing quartile of fatty liver index (p < 0.05).

LIMITATIONS

The study was limited by a relatively healthy Asian population.

CONCLUSION

The high fatty liver index may be a useful predictor of colorectal adenoma. See Video Abstract at http://links.lww.com/DCR/A478.

Plasma amino acid profile associated with fatty liver disease and co-occurrence of metabolic risk factors

Fatty liver disease (FLD) increases the risk of diabetes, cardiovascular disease, and steatohepatitis, which leads to fibrosis, cirrhosis, and hepatocellular carcinoma. Thus, the early detection of FLD is necessary. We aimed to find a quantitative and feasible model for discriminating the FLD, based on plasma free amino acid (PFAA) profiles. We constructed models of the relationship between PFAA levels in 2,000 generally healthy Japanese subjects and the diagnosis of FLD by abdominal ultrasound scan by multiple logistic regression analysis with variable selection. The performance of these models for FLD discrimination was validated using an independent data set of 2,160 subjects. The generated PFAA-based model was able to identify FLD patients. The area under the receiver operating characteristic curve for the model was 0.83, which was higher than those of other existing liver function-associated markers ranging from 0.53 to 0.80. The value of the linear discriminant in the model yielded the adjusted odds ratio (with 95% confidence intervals) for a 1 standard deviation increase of 2.63 (2.14–3.25) in the multiple logistic regression analysis with known liver function-associated covariates. Interestingly, the linear discriminant values were significantly associated with the progression of FLD, and patients with nonalcoholic steatohepatitis also exhibited higher values.

Targeting nuclear receptors for the treatment of fatty liver disease

Ligand-activated nuclear receptors, including peroxisome proliferator-activated receptor alpha (PPARα), pregnane X receptor, and constitutive androstane receptor, were first identified as key regulators of the responses against chemical toxicants. However, numerous studies using mouse disease models and human samples have revealed critical roles for these receptors and others, such as PPARβ/δ, PPARγ, farnesoid X receptor (FXR), and liver X receptor (LXR), in maintaining nutrient/energy homeostasis in part through modulation of the gut-liver-adipose axis. Recently, disorders associated with disrupted nutrient/energy homeostasis, e.g., obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD), are increasing worldwide. Notably, in NAFLD, a progressive subtype exists, designated as non-alcoholic steatohepatitis (NASH) that is characterized by typical histological features resembling alcoholic steatohepatitis (ASH), and NASH/ASH are recognized as major causes of hepatitis virus-unrelated liver cirrhosis and hepatocellular carcinoma. Since hepatic steatosis is basically caused by an imbalance between fat/energy influx and utilization, abnormal signaling of these nuclear receptors contribute to the pathogenesis of fatty liver disease. Standard therapeutic interventions have not been fully established for fatty liver disease, but some new agents that activate or inhibit nuclear receptor signaling have shown promise as possible therapeutic targets. In this review, we summarize recent findings on the roles of nuclear receptors in fatty liver disease and discuss future perspectives to develop promising pharmacological strategies targeting nuclear receptors for NAFLD/NASH.

Undernourishment in utero and hepatic steatosis in later life: A potential issue in Japanese people

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. The prevalence of NAFLD in Japan has nearly doubled in the last 10-15 years. Increasing evidence supports undernourishment in utero being causatively connected with the risk of NAFLD in later life. Low body mass index (BMI) has been common among Japanese women of childbearing age for several decades due to their strong desire to be thin. It is plausible that insufficient maternal energy intake by pregnant Japanese women may underlie the rapid increase in the prevalence of NAFLD in Japan. In order to clarify the mechanisms by which undernourishment in utero primes adult hepatic steatosis, we developed a mouse model of fetal undernourishment with a hepatic fat deposit-prone phenotype on an obesogenic high fat diet in later life. We found that endoplasmic reticulum (ER) stress response parameters were activated concomitantly with the deterioration of hepatic steatosis and also that the alleviation of ER stress with the chemical chaperone, tauroursodeoxycholic acid (TUDCA), significantly improved hepatic steatosis. Therefore, undernourishment in utero may program the future integration of ER stress in the liver on an obesogenic diet in later life and also induce the deterioration of hepatic steatosis. These results also provide an insight into interventions for the potential high-risk population of NAFLD, such as those born small or exposed to maternal undernourishment during the fetal period, with the alleviation of ER stress by dietary supplements and/or specific food including chaperones.

Investigating Molecular Connections of Non-alcoholic Fatty Liver Disease with Associated Pathological Conditions in West Virginia for Biomarker Analysis

Non-alcoholic fatty liver disease (NAFLD) is a disease characterized by a steatosis of the liver that may progress to more serious pathological conditions including: nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. As the prevalence of NAFLD has increased worldwide in recent years, pathophysiology and risk factors associated with disease progression of NAFLD are at the focus of many studies. NAFLD is related to and shares common serum biomarkers with cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), obesity, and metabolic syndrome (MetS). West Virginia (WV) is a state with some of the highest rates of CVD, obesity and diabetes mellitus. As NAFLD is closely related to these diseases, it is of particular interest in WV. Currently there is no cost-effective, standardized method used clinically to detect NAFLD prior to the onset of reversible complications. At this time, the diagnosis of NAFLD is made with costly radiologic studies and invasive biopsy. These studies are only diagnostic once changes to hepatic tissue have occurred. The diagnosis of NAFLD by traditional methods may not allow for successful intervention and may not be readily available in areas with already sparse medical resources. In this literature review, we identify a list of biomarkers common among CVD, T2DM, obesity, MetS and NAFLD. From this research we propose the following biomarkers are good candidates for inclusion in a panel of biomarkers for the early detection of NAFLD: adiponectin, AST, ALT, apo-B, CK18, CPS1, CRP, FABP-1, ferritin, GGT, GRP78, HDL-C, IGF-1, IL-1β, 6, 8, 10, IRS-2PAI-1, leptin, lumican, MDA SREBP-1c and TNF-α. Creating and implementing a biomarker panel for the early detection and attenuation of NAFLD, prior to the onset of irreversible complication would provide maximum benefit and decrease the disease burden on the patients and healthcare system of WV.

Significance of non-alcoholic fatty liver disease in Crohn's disease: A retrospective cohort study

AIM

The prevalence of non-alcoholic fatty liver disease (NAFLD) and Crohn's disease (CD) is increasing. The aim of our study was to evaluate the prevalence of NAFLD in patients with CD, as well as to investigate the effect of NAFLD on the disease course of CD.

METHODS

Our retrospective cohort study included 303 patients who underwent abdominal ultrasound for CD and NAFLD diagnosis at our center between November 2008 and October 2014. Serum C-reactive protein (CRP) level and rate of remission, defined by a score <150 on the Crohn's Disease Activity Index, were compared between CD patients with and without NAFLD, using multivariate logistic regression. The effect of NAFLD on the surgery-free interval was evaluated using Cox proportional hazards models, adjusted for potential demographic confounders.

RESULTS

Non-alcoholic fatty liver disease was diagnosed in 66 (21.8%) patients in our study cohort and was associated with lower CRP levels (0.58 vs. 2.18 mg/dL, P < 0.0001) and a higher rate of remission (75.9% vs. 53.7%, P = 0.0024). Non-alcoholic fatty liver disease was identified as an independent predictor of a negative CRP level (<0.3 mg/dL; odds ratio, 1.85; 95% confidence interval, 1.03-3.37) and higher rate of remission (odds ratio, 2.57; 95% confidence interval, 1.21-5.80). Non-alcoholic fatty liver disease was associated with longer surgery-free interval (log-rank test, P = 0.0035), with NAFLD identified as a positive predictor of surgery-free interval (P = 0.0014).

CONCLUSIONS

Non-alcoholic fatty liver disease may offer a protective effect in patients with CD and could be used as a prognostic marker in patients with CD.

Liver-specific G0 /G1 switch gene 2 (G0s2) expression promotes hepatic insulin resistance by exacerbating hepatic steatosis in male Wistar rats

BACKGROUND

Hepatic steatosis is strongly associated with insulin resistance. It has been reported that G₀ /G₁ switch gene 2 (G0s2) inhibits the lipolytic activity of adipose triglyceride lipase, which is a major lipase in the liver as well as in adipocytes. Moreover, G0s2 protein content is increased in the livers of high-fat diet (HFD)-fed rats. In the present study, we investigated the effect of hepatic G0s2 on insulin sensitivity in male Wistar rats.

METHODS

Male Wistar rats were fed a 60% HFD for 4 weeks. After 3 weeks of feeding, rats were injected with adenovirus-expressing green fluorescent protein (Ad-GFP; control) or adenovirus-expressing mouse G0s2 (Ad-G0s2). On Day 7 after injection, a euglycemic-hyperinsulinemic clamp study was performed in rats fasted for 8 h.

RESULTS

Body weight and fasting glucose levels were not significantly different between the Ad-GFP and Ad-G0s2 groups. During the clamp study, the glucose infusion rate required for euglycemia decreased significantly by 16% in the Ad-G0s2 compared with Ad-GFP group. The insulin-suppressed hepatic glucose output increased significantly in the Ad-G0s2 group, but the insulin-stimulated glucose disposal rate was not significantly different between the two groups. Consistent with the clamp data, insulin-stimulated phosphorylation of Akt decreased significantly in livers of rats injected with Ad-G0s2. Furthermore, Oil Red O-staining indicated that overexpression of G0s2 protein in the liver promoted hepatic steatosis by 2.5-fold in HFD-fed rats.

CONCLUSION

The results of the present study indicate that hepatic G0s2 protein may promote hepatic insulin resistance by exacerbating hepatic steatosis.

An update on non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in Asia

Non-alcoholic fatty liver disease (NAFLD) has become the most overwhelming liver disease in Asia. In consideration of its increasing medical and economic impact on Asian people, it is time for us to review the update data in Asian countries and formulate strategies to cope with this emerging health problem in Asia. Moreover, growing data indicates that NAFLD may be a systemic disease, not just confined to liver-specific morbidity and mortality, but also associated with several extra-hepatic manifestations, such as cardiovascular diseases, chronic renal diseases, and malignancy. As the co-occurrence of NAFLD and viral hepatitis is common in Asia, issues related to the impact of NAFLD on the clinical outcomes and management of viral hepatitis remain to be elucidated. Areas covered: In this article, a narrative review was conducted, searching for literature from PubMed, Ovid MEDLINE, and the Cochrane Library database till August 2016. Studies relevant to the emerging data of NAFLD in Asia, including the diagnosis, risk factors, the assessment and management of Asian NAFLD patients were examined and discussed. Expert commentary: Collaboration in Asian countries to develop an effective and practical measurement to assess the severity of NAFLD is urgently required.

Metabolomic characteristics of cholesterol-induced non-obese nonalcoholic fatty liver disease in mice

Nonalcoholic fatty liver disease (NAFLD) in non-obese patients remains a clinical condition with unclear etiology and pathogenesis. Using a metabolomics approach in a mouse model that recapitulates almost all the characteristic features of non-obese NAFLD, we aimed to advance mechanistic understanding of this disorder. Mice fed high fat, high cholesterol, cholate (HFHCC) diet for three weeks consistently developed hepatic pathology similar to NAFLD and nonalcoholic steatohepatitis (NASH) without changes to body weight or fat pad weights. Gas- and liquid chromatography/mass spectrometry-based profiling of lipidomic and primary metabolism changes in the liver and plasma revealed that systemic mechanisms leading to steatosis and hepatitis in this non-obese NAFLD model were driven by a combination of effects directed by elevated free cholesterol, cholesterol esters and cholic acid, and associated changes to metabolism of sphingomyelins and phosphatidylcholines. These results demonstrate that mechanisms underlying cholesterol-induced non-obese NAFLD are distinct from NAFLD occurring as a consequence of metabolic syndrome. In addition, this investigation provides one of the first metabolite reference profiles for interpreting effects of dietary and hepatic cholesterol in human non-obese NAFLD/NASH patients.

NAFLD as a Sexual Dimorphic Disease: Role of Gender and Reproductive Status in the Development and Progression of Nonalcoholic Fatty Liver Disease and Inherent Cardiovascular Risk

Nonalcoholic fatty liver disease (NAFLD) spans steatosis through nonalcoholic steatohepatis, cirrhosis, and hepatocellular carcinoma (HCC) associated with striking systemic features and excess cardiovascular and liver-related mortality. The pathogenesis of NAFLD is complex and multifactorial. Endocrine derangements are closely linked with dysmetabolic traits. For example, in animal and human studies, female sex is protected from dysmetabolism thanks to young individuals' ability to partition fatty acids towards ketone body production rather than very low density lipoprotein (VLDL)-triacylglycerol, and to sex-specific browning of white adipose tissue. Ovarian senescence facilitates both the development of massive hepatic steatosis and the fibrotic progression of liver disease in an experimental overfed zebrafish model. Consistently, estrogen deficiency, by potentiating hepatic inflammatory changes, hastens the progression of disease in a dietary model of nonalcoholic steatohepatitis (NASH) developing in ovariectomized mice fed a high-fat diet. In humans, NAFLD more often affects men; and premenopausal women are equally protected from developing NAFLD as they are from cardiovascular disease. It would be expected that early menarche, definitely associated with estrogen activation, would produce protection against the risk of NAFLD. Nevertheless, it has been suggested that early menarche may confer an increased risk of NAFLD in adulthood, excess adiposity being the primary culprit of this association. Fertile age may be associated with more severe hepatocyte injury and inflammation, but also with a decreased risk of liver fibrosis compared to men and postmenopausal status. Later in life, ovarian senescence is strongly associated with severe steatosis and fibrosing NASH, which may occur in postmenopausal women. Estrogen deficiency is deemed to be responsible for these findings via the development of postmenopausal metabolic syndrome. Estrogen supplementation may at least theoretically protect from NAFLD development and progression, as suggested by some studies exploring the effect of hormonal replacement therapy on postmenopausal women, but the variable impact of different sex hormones in NAFLD (i.e., the pro-inflammatory effect of progesterone) should be carefully considered.

Association between the hyperuricemia and nonalcoholic fatty liver disease risk in a Chinese population: A retrospective cohort study

Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease associated with high levels of serum uric acid (SUA). However, whether this relationship applies in obese subjects has been unclear, and no cohort study has previously been conducted in non-obese subjects. We therefore performed a retrospective cohort study among employees of seven companies in China to investigate whether hyperuricemia was independently associated with NAFLD in obese and non-obese subjects, respectively. A total of 2383 initially NAFLD-free subjects were followed up for four years, and 15.2% (363/2383) developed NAFLD. Hyperuricemia subjects had a higher cumulative incidence than did those with normouricemia (29.0% vs. 12.9%, P<0.001). Cox proportional hazard regression analyses showed that baseline hyperuricemia was significantly associated with risk of developing NAFLD in non-obese subjects. This relationship was significantly independent of baseline age, gender, metabolic syndrome components, and other clinical variables (RR = 1.389, 95%CI: 1.051-2.099). However, this association did not exist in obese subjects (RR = 1.010, 95%CI: 0.649-1.571). The independent effect of hyperuricemia on NAFLD was stronger in females (RR = 2.138, 95%CI: 1.050-4.355) than in males (RR = 1.435, 95%CI: 1.021-2.018). In conclusion, further studies are needed to explore the different mechanisms between obese and non-obese subjects, and the reason hyperuricemia raises NAFLD risk in females more than in males.

High Fat Diet-Induced Hepatic 18-Carbon Fatty Acids Accumulation Up-Regulates CYP2A5/CYP2A6 via NF-E2-Related Factor 2

To investigate the role of hepatic 18-carbon fatty acids (FA) accumulation in regulating CYP2A5/2A6 and the significance of Nrf2 in the process during hepatocytes steatosis, Nrf2-null, and wild type mice fed with high-fat diet (HFD), and Nrf2 silenced or over expressed HepG2 cells administered with 18-carbon FA were used. HE and Oil Red O staining were used for mice hepatic pathological examination. The mRNA and protein expressions were measured with real-time PCR and Western blot. The results showed that hepatic CYP2A5 and Nrf2 expression levels were increased in HFD fed mice accompanied with hepatic 18-carbon FA accumulation. The Nrf2 expression was increased dose-dependently in cells administered with increasing concentrations of stearic acid, oleic acid, and alpha-linolenic acid. The Nrf2 expression was dose-dependently decreased in cells treated with increasing concentrations of linoleic acid, but the Nrf2 expression level was still found higher than the control cells. The CYP2A6 expression was increased dose-dependently in increasing 18-carbon FA treated cells. The HFD-induced up-regulation of hepatic CYP2A5 in vivo and the 18-carbon FA treatment induced up-regulation of CYP2A6 in HepG2 cells were, respectively, inhibited by Nrf2 deficiency and Nrf2 silencing. While the basal expression of mouse hepatic CYP2A5 was not impeded by Nrf2 deletion. Nrf2 over expression improved the up-regulation of CYP2A6 induced by 18-carbon FA. As the classical target gene of Nrf2, GSTA1 mRNA relative expression was increased in Nrf2 over expressed cells and was decreased in Nrf2 silenced cells. In presence or absence of 18-carbon FA treatment, the change of CYP2A6 expression level was similar to GSTA1 in Nrf2 silenced or over expressed HepG2 cells. It was concluded that HFD-induced hepatic 18-carbon FA accumulation contributes to the up-regulation of CYP2A5/2A6 via activating Nrf2. However, the CYP2A5/2A6 expression does not only depend on Nrf2.

Risk of Obesity-Related Cardiometabolic Complications in Special Populations: A Crisis in Asians

The prospect of a significant increase in global health-related costs associated with high cardiometabolic complications of obesity in Asians has encouraged more attention to be focused on the problem of growing obesity prevalence in these populations. Although these studies have shown that cardiometabolic complications occur more frequently and at a lower body mass index (BMI) in Asians than in European populations, the mechanisms involved have yet to be discovered. Ethnic/racial differences in body composition and fat distribution have been studied extensively. Although these studies have shown that increasing BMI is associated with larger increases in body fat content in Asians, growing evidence points to factors other than body fat content and fat distribution in determining a higher prevalence of cardiometabolic complications in these populations. Here, we provide support to our view that earlier onset of adipocyte maturation arrest/insulin resistance during weight gain could be a major factor in increasing the cardiometabolic risk of Asian populations at a lower BMI.

Cannabis use is associated with reduced prevalence of non-alcoholic fatty liver disease: A cross-sectional study

Cannabis use is associated with reduced prevalence of obesity and diabetes mellitus (DM) in humans and mouse disease models. Obesity and DM are a well-established independent risk factor for non-alcoholic fatty liver disease (NAFLD), the most prevalent liver disease globally. The effects of cannabis use on NAFLD prevalence in humans remains ill-defined. Our objective is to determine the relationship between cannabis use and the prevalence of NAFLD in humans. We conducted a population-based case-control study of 5,950,391 patients using the 2014 Healthcare Cost and Utilization Project (HCUP), Nationwide Inpatient Survey (NIS) discharge records of patients 18 years and older. After identifying patients with NAFLD (1% of all patients), we next identified three exposure groups: non-cannabis users (98.04%), non-dependent cannabis users (1.74%), and dependent cannabis users (0.22%). We adjusted for potential demographics and patient related confounders and used multivariate logistic regression (SAS 9.4) to determine the odds of developing NAFLD with respects to cannabis use. Our findings revealed that cannabis users (dependent and non-dependent) showed significantly lower NAFLD prevalence compared to non-users (AOR: 0.82[0.76-0.88]; p<0.0001). The prevalence of NAFLD was 15% lower in non-dependent users (AOR: 0.85[0.79-0.92]; p<0.0001) and 52% lower in dependent users (AOR: 0.49[0.36-0.65]; p<0.0001). Among cannabis users, dependent patients had 43% significantly lower prevalence of NAFLD compared to non-dependent patients (AOR: 0.57[0.42-0.77]; p<0.0001). Our observations suggest that cannabis use is associated with lower prevalence of NAFLD in patients. These novel findings suggest additional molecular mechanistic studies to explore the potential role of cannabis use in NAFLD development.

Novel circulating biomarkers for non-alcoholic fatty liver disease: A systematic review

Currently, a liver biopsy remains the only reliable way to precisely diagnose non-alcoholic fatty liver disease (NAFLD) and establish the severity of liver injury, presence of fibrosis, and architecture remodeling. However, the cost and the intrinsic invasive procedure of a liver biopsy rules it out as a gold standard diagnostic test, and the imaging test are not the best choice due to the price, and currently is being refined. The lack of a biomarker of NAFLD pushes to develop this new line of research. The aim of the present systematic review is to clarify and update all the NAFLD biomarkers described in the literature until recently. We highlight α-ketoglutarate and CK18-F as currently the best potential biomarker of NAFLD. However, due to methodological differences, we propose the implementation of international, multicenter, multiethnic studies with larger population size, and biopsy proven NAFLD diagnosis to analyze and compare α-ketoglutarate and CK18-F as potential biomarkers of the silent evolution of NAFLD.

Nutritional Approaches to Achieve Weight Loss in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) can range in spectrum from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH), which is characterized by lipotoxicity, hepatocellular ballooning, and inflammation and can progress to cirrhosis. Weight loss is the cornerstone treatment for NAFLD and NASH. Various randomized controlled trials have shown that weight loss of ≥5-10% leads to significant improvements in hepatic steatosis. Diets high in sodium and fructose have been implicated in the pathogenesis of NAFLD. Although some clinical studies suggest that an isocaloric high-fructose diet does not worsen NAFLD, these clinical studies are often short in duration. More recently, the Dietary Approaches to Stop Hypertension diet, a sodium-restricted diet, has been associated with less prevalence of NAFLD and has been shown to improve NAFLD. In addition, the Mediterranean diet has been promising in improving hepatic steatosis, and a larger randomized controlled trial is currently enrolling subjects. For those who are unable to pursue weight loss through dietary approaches, bariatric surgery has been shown to improve hepatic steatosis and steatohepatitis. This method has been variable in improving hepatic fibrosis. In conclusion, weight loss is crucial to the improvement of NAFLD and NASH, and patients should attempt various diets in an attempt to achieve weight loss.

High-normal levels of hs-CRP predict the development of non-alcoholic fatty liver in healthy men

We performed a follow-up study to address whether high sensitivity C-reactive protein (hs-CRP) levels within the normal range can predict the development of non-alcoholic fatty liver disease (NAFLD) in healthy male subjects. Among15347 male workers between 30 and 59 years old who received annual health check-ups in 2002, a NAFLD-free cohort of 4,138 was followed through December 2009. Alcohol consumption was assessed with a questionnaire. At each visit, abdominal ultrasonography was performed to identify fatty liver disease. The COX proportional hazard model was used to evaluate the relationship between hs-CRP and incident NAFLD. During the follow-up period, 28.8% (1191 of 4138) of participants developed NAFLD. The hazard ratios of NAFLD were increased by hs-CRP categories within the normal range in the non-adjusted model and age-adjusted model. After adjusting for age, exercise, smoking, BMI, systolic BP, triglyceride, and fasting glucose, these incidences were only increased between the lowest and the highest hs-CRP categories. The risk for NAFLD increased as the hs-CRP level increased (p< 0.001). As the hs-CRP level increased within the healthy cohort, the risk of developing NAFLD increased. This trend remained true even if the hs-CRP level remained within the normal range. hs-CRP can be used as a predictor of NAFLD, as well as other obesity-associated diseases. Therefore, individuals with higher hs-CRP levels (even within the normal range) may require appropriate follow-up and management to prevent NAFLD development.

Influence of hyperglycemia on liver inflammatory conditions in the early phase of non-alcoholic fatty liver disease in mice

OBJECTIVES

A non-alcoholic fatty liver disease (NAFLD) has high prevalence and now important issue of public health. In general, there exists strong interaction between NAFLD and diabetes, but the detailed mechanism is unclear. In this study, we determined the effects of hyperglycemia on progression in the early phase of NAFLD in mice.

METHODS

Male ddY mice were fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) consisting of 60% of kcal from fat and 0.1% methionine by weight. Hyperglycemic condition was induced by streptozotocin (STZ) treatment. The assessment of liver function used serum AST and ALT levels, and histological analysis. Hepatic tumour necrosis factor (TNF)-α mRNA levels was estimated by qRT-PCR.

KEY FINDINGS

During the 3-42 days that the mice were fed CDAHFD, the livers gradually caused accumulation of fat, and infiltration of inflammation cells gradually increased. Serum AST and ALT levels and significantly increased after being fed CDAHFD for 3 days and were exacerbated by the STZ-induced hyperglycemic condition. In addition, hepatic TNF-α mRNA also significantly increased. These phenomena reversed by insulin administration.

CONCLUSIONS

The results showed that progression in the early phase of NAFLD may be exacerbated by hyperglycemia-induced exacerbation of inflammation.

Nonalcoholic fatty liver disease in Asia: emerging perspectives

As in the West, nonalcoholic fatty liver disease (NAFLD) is the commonest chronic liver disease in Asia, with a prevalence higher than 40 % in some countries. The risk factors for NAFLD development are similar to those in Western countries, including increased body mass index, diabetes, insulin resistance, and metabolic syndrome. NAFLD in Asians is associated with different extrahepatic manifestations involving the cardiovascular, gastrointestinal, and renal systems. A considerable proportion of Asians with NAFLD are described as having "lean" NAFLD. Present in approximately 20 % of the Asian population, lean NAFLD is closely linked with insulin resistance, diabetes, and other metabolic complications, but its association with disease progression to nonalcoholic steatohepatitis and cirrhosis remains to be defined. There is emerging evidence of the interactions of NAFLD with hepatitis B virus and hepatitis C virus infection in Asia. Unlike in Western countries, NAFLD constitutes only a minority of cirrhosis and hepatocellular carcinoma cases in Asia. Possible explanations are the lower prevalence of obesity and the overwhelming problem of viral hepatitis in Asia. With aging of the obesity cohort in Asia, NAFLD-related liver complications are expected to increase.

Differences in the risk of fatty liver for onset of impaired fasting glucose according to baseline plasma glucose levels

BACKGROUND

It remains unclear whether fatty liver is a risk factor for the onset of abnormal glucose tolerance in any patient. The objective of this study was to clarify the relationship between fatty liver and the onset of impaired fasting glucose according to baseline fasting plasma glucose (FPG) levels.

METHODS

This community-based longitudinal cohort study included 7,905 adults (3,863 men, 4,042 women; age range, 18-80 years) who had at least two annual checkups between 2003 and 2013. Those with FPG levels ≥110 mg/dl, taking anti-diabetic agents, and/or testing positive for hepatitis B surface antigen or anti-hepatitis C virus antibody were excluded, leaving 7,203 participants eligible for inclusion. All participants were divided into quartiles derived from their FPG levels at baseline. FPG ≥110 mg/dl during the observation period was defined as onset of IFG.

RESULTS

Onset of IFG was found in 7.7 % of men and 2.1 % of women (p < 0.001). After adjusting for age, body mass index, systolic blood pressure, triacylglycerol, high-density lipoprotein cholesterol, uric acid, creatinine, family history of diabetes, alcohol consumption, and current smoking, a positive association was found between fatty liver and the onset of IFG in both sexes with the highest quartile of FPG levels [men: adjusted hazard ratio (aHR) 1.823, 95 % confidence interval (CI) 1.316-2.534, p < 0.001; women: aHR 2.016, 95 % CI 1.117-3.6, p = 0.02].

CONCLUSIONS

Our results suggest that fatty liver is independently associated with an increased risk of developing IFG in individuals with high FPG.

Prevalence and risk factors of advanced colorectal neoplasms in asymptomatic Korean people between 40 and 49 years of age

BACKGROUND AND AIM

Current guidelines recommend colon cancer screening for persons aged over 50 years. However, there are few data on colorectal cancer screening in 40- to 49-year-olds. This study assessed the prevalence and risk factors of colorectal neoplasms in 40- to 49-year-old Koreans.

METHODS

We analyzed the results of screening colonoscopies of 6680 persons 40-59 years of age (2206 aged 40-49 and 4474 aged 50-59 years).

RESULTS

The prevalence of overall and advanced neoplasms in the 40- to 49-year age group was lower than in the 50- to 59-year age group (26.7% and 2.4% vs 37.8% and 3.5%, respectively). However, the prevalence of overall and advanced neoplasms increased to 39.1% and 5.4%, respectively, in 45- to 49-year-old individuals with metabolic syndrome. In the 40- to 49-year age group, age, current smoking, and metabolic syndrome were associated with an increased risk of advanced neoplasms (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.04-1.30; OR 3.12, 95% CI 1.20-8.12; and OR 2.00, 95% CI 1.09-3.67, respectively).

CONCLUSIONS

Individuals aged 40-49 years had a lower prevalence of colorectal neoplasms than those aged 50-59 years, but some 40- to 49-year-olds showed a similar prevalence to those aged 50-59 years. Age, current smoking habits, and metabolic syndrome are associated with an increased risk of advanced neoplasms in subjects aged 40-49 years. Further studies are needed to stratify the risks of colon cancer and guide targeted screening in persons younger than 50 years old.

Is Vitamin D an Independent Risk Factor of Nonalcoholic Fatty Liver Disease?: a Cross-Sectional Study of the Healthy Population

The association between vitamin D levels and nonalcoholic fatty liver disease (NAFLD) has been recognized. However, few studies showed independent associations between vitamin D deficiency and NAFLD after a sex-related adjustment for metabolic factors. We aimed to study whether vitamin D deficiency is an independent risk factor of NAFLD even after controlling for metabolic syndrome and visceral fat in both sexes. In this cross-sectional study, 7,514 Korean adults (5,278 men, 2,236 women) participated in a health check-up program. They underwent blood tests, abdominal computed tomography (CT) of the visceral fat area, and ultrasonography for NAFLD screening. Multiple logistic regression analysis was used to investigate the association of vitamin D deficiency with NAFLD according to the sex differences. Vitamin D deficiency is associated with NAFLD. The adjusted odds ratio (aOR) for NAFLD increased sequentially with decreasing vitamin D level, even after adjusting for metabolic syndrome and visceral fat. The subjects in the vitamin D sufficiency group (20-30 ng/mL) had an aOR for NAFLD of 1.18 (95% CI, 1.00-1.39), whereas the deficiency group (< 20 ng/mL) had an aOR of 1.29 (95% CI, 1.10-1.52). However, we have detected a significant sex-related interaction when analyzing the results. A significant relationship between vitamin D deficiency and NAFLD was found in men (aOR, 1.33; 95% CI, 1.11-1.60) but not in women.

Patient Sex, Reproductive Status, and Synthetic Hormone Use Associate With Histologic Severity of Nonalcoholic Steatohepatitis

BACKGROUND & AIMS

Sex and sex hormones can affect responses of patients with nonalcoholic fatty liver disease (NAFLD) to metabolic stress and development of hepatocyte injury and inflammation.

METHODS

We collected data from 3 large U.S. studies of patients with NAFLD (between October 2004 and June 2013) to assess the association between histologic severity and sex, menopause status, synthetic hormone use, and menstrual abnormalities in 1112 patients with a histologic diagnosis of NAFLD. We performed logistic or ordinal logistic regression models, adjusting for covariates relevant to an increase of hepatic metabolic stress.

RESULTS

Premenopausal women were at an increased risk of lobular inflammation, hepatocyte ballooning, and Mallory-Denk bodies than men and also at an increased risk of lobular inflammation and Mallory-Denk bodies than postmenopausal women (P < .01). Use of oral contraceptives was associated with an increased risk of lobular inflammation and Mallory-Denk bodies in premenopausal women, whereas hormone replacement therapy was associated with an increased risk of lobular inflammation in postmenopausal women (P < .05).

CONCLUSIONS

Being a premenopausal woman or a female user of synthetic hormones is associated with increased histologic severity of hepatocyte injury and inflammation among patients with NAFLD at given levels of hepatic metabolic stress.

Prevalence of chronic liver disease and cirrhosis by underlying cause in understudied ethnic groups: The multiethnic cohort

Chronic liver disease (CLD) and cirrhosis are major sources of morbidity and mortality in the United States. Little is known about the epidemiology of these two diseases in ethnic minority populations in the United States. We examined the prevalence of CLD and cirrhosis by underlying etiologies among African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites in the Multiethnic Cohort. CLD and cirrhosis cases were identified using Medicare claims between 1999 and 2012 among the fee-for-service participants (n = 106,458). We used International Classification of Diseases Ninth Revision codes, body mass index, history of diabetes mellitus, and alcohol consumption from questionnaires to identify underlying etiologies. A total of 5,783 CLD (3,575 CLD without cirrhosis and 2,208 cirrhosis) cases were identified. The prevalence of CLD ranged from 3.9% in African Americans and Native Hawaiians to 4.1% in whites, 6.7% in Latinos, and 6.9% in Japanese. Nonalcoholic fatty liver disease (NAFLD) was the most common cause of CLD in all ethnic groups combined (52%), followed by alcoholic liver disease (21%). NAFLD was the most common cause of cirrhosis in the entire cohort. By ethnicity, NAFLD was the most common cause of cirrhosis in Japanese Americans, Native Hawaiians, and Latinos, accounting for 32% of cases. Alcoholic liver disease was the most common cause of cirrhosis in whites (38.2%), while hepatitis C virus was the most common cause in African Americans (29.8%).

CONCLUSIONS

We showed racial/ethnic variations in the prevalence of CLD and cirrhosis by underlying etiology; NAFLD was the most common cause of CLD and cirrhosis in the entire cohort, and the high prevalence of NAFLD among Japanese Americans and Native Hawaiians is a novel finding, warranting further studies to elucidate the causes. (Hepatology 2016;64:1969-1977).

Low alcohol consumption increases the risk of impaired glucose tolerance in patients with non-alcoholic fatty liver disease

BACKGROUND

Fatty liver disease is associated with glucose intolerance and hepatic insulin resistance. However, there are distinct etiologies for alcoholic versus non-alcoholic fatty liver disease (NAFLD), and it is unknown whether alcohol consumption influences the onset of glucose intolerance in fatty liver disease patients. Therefore, we investigated the relationship between fatty liver disease and the onset of impaired fasting glucose (IFG) with respect to alcohol consumption.

METHODS

The records of 6804 Japanese subjects were reviewed to identify those meeting the criteria for IFG. Male and female subjects were classified into five and four groups, respectively, based on average alcohol consumption (g/week). IFG onset was defined as fasting plasma glucose levels ≥110 mg/dl.

RESULTS

In the non-drinker, >0-70 g/week, >70-140 g/week, >140-210 g/week (men only), and >210 g/week (men only) or >140 g/week (women only) groups, 7.3, 6.7, 6.4, 9, and 6.4 % of men and 2, 1.7, 3.1, and 3.2 % of women, respectively, developed IFG. Fatty liver was positively associated with the onset of IFG in men of the >0-70 g/week group (adjusted hazard ratio [aHR], 2.808; 95 % confidence interval [CI] 1.605-5.049, p < 0.001) and women of the >70-140 g/week group (aHR, 4.193; 95 % CI, 1.036-14.584, p = 0.045) after adjusting for previously reported IFG risk factors. No associations were observed in the other groups.

CONCLUSIONS

A small amount of alcohol consumption is a significant risk factor for the onset of IFG in NAFLD patients; onset risk differs according to the amount of alcohol consumption.

Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) has become a major cause of cirrhosis and liver-related deaths worldwide. NASH is strongly associated with obesity and the metabolic syndrome, conditions that cause lipid accumulation in hepatocytes (hepatic steatosis). It is not well understood why some, but not other, individuals with hepatic steatosis develop NASH. The factors that determine whether or not NASH progresses to cirrhosis are also unclear. This review summarizes key components of NASH pathogenesis and discusses how inherent and acquired variations in regulation of these processes impact the risk for NASH and NASH cirrhosis.

Prevalence and Factors Associated with Nonalcoholic Fatty Liver Disease in a Nonobese Korean Population

Background/Aims

Nonalcoholic fatty liver disease (NAFLD) is an emerging problem in Asia, but little is known about the disease in the nonobese population. The aims of this study were to investigate the prevalence of NAFLD and the factors associated with it in a nonobese Korean population and to compare the clinical characteristics of nonobese and obese subjects with NAFLD.

Methods

This cross-sectional study used data from 2,058 subjects who participated in a medical checkup program.

Results

The prevalence of NAFLD was 12.4% (213/1,711) in the nonobese population. A higher body mass index (BMI), higher homeostasis model assessment of insulin resistance (HOMA-IR) values, higher alanine aminotransferase (ALT) levels, triglyceride concentrations 150 mg/dL, and hyperuricemia were independently associated with the presence of NAFLD in the nonobese subjects. Compared with the obese subjects with NAFLD, the nonobese subjects with NAFLD were composed of a higher proportion of females and had lower BMIs, smaller waist circumferences, lower HOMA-IR values, and fewer metabolic irregularities.

Conclusions

Higher BMIs, HOMA-IR values, ALT levels, hypertriglyceridemia, and hyperuricemia were associated with NAFLD in the nonobese subjects. Clinicians should be particularly aware of the possibility of NAFLD in nonobese Asian people.

Characteristics of non-obese non-alcoholic fatty liver disease: Effect of genetic and environmental factors

AIM

There are a considerable number of patients with non-obese non-alcoholic fatty liver disease (NAFLD). However, the clinical characteristics of non-obese NAFLD is not fully understood. We investigated genetic and other clinical parameters in non-obese and obese NAFLD.

METHODS

The single nucleotide polymorphism rs738409 in the patatin-like phospholipase 3 gene (PNPLA3) was genotyped by the Invader assay in 540 NAFLD patients (134 non-obese and 406 obese) and 1012 control subjects (782 non-obese and 230 obese). All NAFLD patients underwent liver biopsy. Odds ratios were calculated by multiple logistic regression analysis using age, sex, body mass index (BMI), type 2 diabetes mellitus (T2DM) and rs738409 genotype as explanatory variables.

RESULTS

Non-obese NAFLD subjects had a higher rs738409 GG genotype than obese NAFLD. Multiple logistic regression analysis indicated that the odds ratios of T2DM and rs738409 GG genotype for NAFLD were higher in non-obese than in obese groups. In non-obese NAFLD, rs738409 GG genotype was associated with lobular inflammation, hepatocyte ballooning and NAFLD activity score. In obese NAFLD, BMI and T2DM but not rs738409 GG genotype were associated with severity of histology.

CONCLUSION

We demonstrated that the risk factors for the development and progression of NAFLD were different between non-obese and obese patients and that PNPLA3 rs738409 was strongly associated with the development and progression of non-obese NAFLD.

Stereological Analysis of Liver Biopsy Histology Sections as a Reference Standard for Validating Non-Invasive Liver Fat Fraction Measurements by MRI

Background and Aims

Validation of non-invasive methods of liver fat quantification requires a reference standard. However, using standard histopathology assessment of liver biopsies is problematical because of poor repeatability. We aimed to assess a stereological method of measuring volumetric liver fat fraction (VLFF) in liver biopsies and to use the method to validate a magnetic resonance imaging method for measurement of VLFF.

Methods

VLFFs were measured in 59 subjects (1) by three independent analysts using a stereological point counting technique combined with the Delesse principle on liver biopsy histological sections and (2) by three independent analysts using the HepaFat-Scan^® technique on magnetic resonance images of the liver. Bland Altman statistics and intraclass correlation (IC) were used to assess the repeatability of each method and the bias between the methods of liver fat fraction measurement.

Results

Inter-analyst repeatability coefficients for the stereology and HepaFat-Scan^® methods were 8.2 (95% CI 7.7–8.8)% and 2.4 (95% CI 2.2–2.5)% VLFF respectively. IC coefficients were 0.86 (95% CI 0.69–0.93) and 0.990 (95% CI 0.985–0.994) respectively. Small biases (≤3.4%) were observable between two pairs of analysts using stereology while no significant biases were observable between any of the three pairs of analysts using HepaFat-Scan^®. A bias of 1.4±0.5% VLFF was observed between the HepaFat-Scan^® method and the stereological method.

Conclusions

Repeatability of the stereological method is superior to the previously reported performance of assessment of hepatic steatosis by histopathologists and is a suitable reference standard for validating non-invasive methods of measurement of VLFF.

The intrahepatic expression levels of bile acid transporters are inversely correlated with the histological progression of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) presents as a spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH). The latter is progressive, and its pathogenesis remains poorly understood. Recently, bile acid (BA) metabolism has become a therapeutic focus in NASH patients. The aim of the present study was to explore changes in bile acid metabolism in NAFLD patients in the context of disease progression.

METHODS

We prospectively enrolled patients with clinically suspected NAFLD. Patients taking ursodeoxycholic acid were excluded. The intrahepatic expression levels of genes associated with BA metabolism were determined by quantitative PCR and immunohistochemistry.

RESULTS

Seventy-eight patients (male:female = 49:29) histologically diagnosed with NAFLD were analyzed. The expression levels of farnesoid X receptor, liver receptor homolog 1, and small heterodimer partner, key proteins in BA synthesis, significantly decreased as the NAFLD activity score (NAS) increased in either males or females. The levels of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme of BA synthesis, were not changed. Notably, the expression levels of a main export transporter, bile salt export pump (BSEP), significantly decreased as the NAS and the each NAS component increased in both genders. The decreases of BSEP levels were also observed by immunohistochemistry, particularly in areas with pronounced fatty changes in cases with high NAS.

CONCLUSIONS

The expression levels of the BA export transporter BSEP were inversely correlated with NAS in NAFLD patients. Such down-regulation may cause excessive BA levels in hepatocytes, leading to cell injury. Our findings may afford new insights into the pathogenesis of NASH.

The Relationship between Type 2 Diabetes Mellitus and Non-Alcoholic Fatty Liver Disease Measured by Controlled Attenuation Parameter

PURPOSE

The severity of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM) population compared with that in normal glucose tolerance (NGT) individuals has not yet been quantitatively assessed. We investigated the prevalence and the severity of NAFLD in a T2DM population using controlled attenuation parameter (CAP).

MATERIALS AND METHODS

Subjects who underwent testing for biomarkers related to T2DM and CAP using Fibroscan® during a regular health check-up were enrolled. CAP values of 250 dB/m and 300 dB/m were selected as the cutoffs for the presence of NAFLD and for moderate to severe NAFLD, respectively. Biomarkers related to T2DM included fasting glucose/insulin, fasting C-peptide, hemoglobin A1c (HbA1c), glycoalbumin, and homeostasis model assessment of insulin resistance of insulin resistance (HOMA-IR).

RESULTS

Among 340 study participants (T2DM, n=66; pre-diabetes, n=202; NGT, n=72), the proportion of subjects with NAFLD increased according to the glucose tolerance status (31.9% in NGT; 47.0% in pre-diabetes; 57.6% in T2DM). The median CAP value was significantly higher in subjects with T2DM (265 dB/m) than in those with pre-diabetes (245 dB/m) or NGT (231 dB/m) (all p<0.05). Logistic regression analysis showed that subjects with moderate to severe NAFLD had a 2.8-fold (odds ratio) higher risk of having T2DM than those without NAFLD (p=0.02; 95% confidence interval, 1.21-6.64), and positive correlations between the CAP value and HOMA-IR (ρ0.407) or fasting C-peptide (ρ0.402) were demonstrated.

CONCLUSION

Subjects with T2DM had a higher prevalence of severe NAFLD than those with NGT. Increased hepatic steatosis was significantly associated with the presence of T2DM, and insulin resistance induced by hepatic fat may be an important mechanistic connection.

[Mechanism Analysis and Prevention of Pathogenesis of Nonalcoholic Steatohepatitis]

Nonalcoholic fatty liver disease (NAFLD) is a common disease in humans having a broad spectrum of liver histology from simple fatty liver to mixed inflammatory cell infiltration and fibrosis (nonalcoholic steatohepatitis, NASH), which is a more severe and progressing form. NASH/NAFLD is significantly associated with lifestyle such as diet and exercise, obesity, insulin resistance, type 2 diabetes, dyslipidemia and hypertension. Age and gender are also associated with the development. On the other hand, NAFLD has been found in a high percentage of nonobese individuals in the Asia-Pacific area. Some characteristic animal models of NAFLD/NASH have been developed to clarify the pathogenesis of human NAFLD/NASH. We have recently developed a novel NASH rat model (stroke-prone spontaneously hypertensive rats, SHRSP5/Dmcr), which showed hepatic steatosis and inflammation at 2 weeks, ballooning, macrovesicular steatosis and fibrosis at 8 weeks, and bridging fibrosis at 14 weeks by feeding of high-fat and -cholesterol (HFC) diet alone. This animal model does not have obesity, insulin resistance or diabetes. Therefore, this may be an excellent animal model of human NASH/NAFLD without obesity and diabetes. Sex and strain differences observed in fibrogenesis by the HFC diet in SHRSP5/Dmcr may be associated with the sensitivity to detoxification enzymes in the liver, because the levels of UGP-glucuronosyltransferase and sulfotransferase and their regulating nuclear receptors only decreased in male SHRSP5/Dmcr rats, but not in female and SHRSP rats. This suggests the importance of phase II reactions of drug-metabolizing enzymes in NASH progression. Importantly, SHRSP5/Dmcr rats are spontaneously hypertensive; therefore, when we use the original strain Wistar Kyoto, which has normal blood pressure, the involvement of blood pressure in the development of human NASH/NAFLD may also be clarified.

Comparison of the Phenotype and Approach to Pediatric vs Adult Patients With Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is one of the main chronic noncommunicable diseases in Westernized societies; its worldwide prevalence has doubled during the last 20 years. NAFLD has serious health implications not only for adults, but also for children. However, pediatric NAFLD is not only an important global problem in itself, but it is likely to be associated with increases in comorbidities, such as metabolic syndrome and cardiovascular diseases. There are several differences between NAFLD in children and adults, and it is not clear whether the disease observed in children is the initial phase of a process that progresses with age. The increasing prevalence of pediatric NAFLD has serious implications for the future adult population requiring appropriate action. Studies of NAFLD progression, pathogenesis, and management should evaluate disease phenotypes in children and follow these over the patient's lifetime. We review the similarities and differences of NAFLD between children and adults.

Fatty acid composition in serum correlates with that in the liver and non-alcoholic fatty liver disease activity scores in mice fed a high-fat diet

In this study, we investigated the correlation between the serum fatty acid composition and hepatic steatosis, inflammation, hepatocellular ballooning scores, and liver fatty acids composition in mice fed a high-fat diet. Livers were collected for non-alcoholic fatty liver disease score analysis. Fatty acid compositions were analysed by gas chromatography. Correlations were determined by Pearson correlation coefficient. Exposed to a high-fat diet, mice developed fatty liver disease with varying severity without fibrosis. The serum fatty acid variation became more severe with prolonged exposure to a high-fat diet. This variation also correlated significantly with the variation in livers, with the types of fatty acids corresponding to liver steatosis, inflammation, and hepatocellular ballooning scores. Results of this study lead to the following hypothesis: the extent of serum fatty acid variation may be a preliminary biomarker of fatty liver disease caused by high-fat intake.

Global Epidemiology of Nonalcoholic Fatty Liver Disease and Perspectives on US Minority Populations

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a clinical syndrome predicted to be the next global epidemic affecting millions of people worldwide. The natural course of this disease including its subtype, non-alcoholic steatohepatitis (NASH), is not clearly defined especially in the African-American segment of the US population.

AIMS

To conduct a review of the global epidemiology of NAFLD with emphasis on US minority populations.

METHODS

A thorough search of evidence-based literature was conducted using the Pubmed database and commercial web sources such as Medscape and Google Scholar.

RESULTS

NAFLD and its subtype NASH are becoming the principal cause of chronic liver disease across the world. In the US, Hispanics are the most disproportionately affected ethnic group with hepatic steatosis, and elevated aminotransferase levels, whereas African-Americans are the least affected. Genetic disparities involved in lipid metabolism seem to be the leading explanation for the lowest incidence and prevalence of both NAFLD and NASH in African-Americans.

CONCLUSIONS

The unprecedented rise in the prevalence of NAFLD globally requires an initiation of population cohort studies with long-term follow-up to determine the incidence and natural history of NAFLD and its underrepresentation in African-Americans. Future studies should also focus on the delineation of the interplay between genetic and environmental factors that trigger the development of NAFLD and NASH.

Triglycerides to high-density lipoprotein cholesterol ratio is an independent predictor of incident fatty liver; a population-based cohort study

BACKGROUND

Triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) ratio (TG/HDL-C) has been recommended for surrogates of insulin resistance. However, it remains to be elucidated the association between TG/HDL-C and incident fatty liver.

AIMS

To investigate the association between TG/HDL-C and incident fatty liver.

METHODS

We performed population-based historical cohort study consisted with 4518 healthy Japanese who received yearly health-checkup programmes over decade. Fatty liver was diagnosed using ultrasonography.

RESULTS

During the observation periods, 38.8% (case/N = 1023/2637) of men and 17.2% (case/N = 324/1881) of women developed fatty liver. Adjusting odds ratio of TG/HDL-C for incident fatty liver were 1.59 (95% confidence interval (CI) 1.42-1.79, P < 0.0001) in men and 2.50 (95% CI 1.80-3.51, P < 0.0001) in women. In addition, adjusting odds ratio of TG/HDL-C for incident non-alcoholic fatty liver disease were 1.55 (95% CI 1.35-1.77, P < 0.0001) in men and 2.72 (95% CI 1.88-3.95, P < 0.0001) in women. According to the receiver operator characteristic (ROC) analysis, the optimal cut-off point of TG/HDL-C for incident fatty liver was 0.88 (area under the ROC curve (AUC) 0.67 [95% CI 0.65-0.69], sensitivity = 0.64, specificity = 0.60, P < 0.0001) in men and 0.64 (AUC 0.69 [95% CI 0.66-0.72], sensitivity = 0.50, specificity = 0.78, P < 0.0001) in women.

CONCLUSIONS

The TG/HDL-C could predict the incident fatty liver. Thus, it is important to check TG/HDL-C and lifestyles modification is needed for preventing future fatty liver disease in patients with high TG/HDL-C.