Clinical, laboratory and histological associations in adults with nonalcoholic fatty liver disease

Sex differences in the impact of nonalcoholic fatty liver disease on cardiovascular risk factors

BACKGROUND AND AIMS

Information on sex differences in the association of nonalcoholic fatty liver disease (NAFLD) with cardiovascular disease (CVD) risk factors is scarce. We examined whether men exhibit greater differences in established CVD risk factors between NAFLD and non-NAFLD than women.

METHODS AND RESULTS

We conducted a cross-sectional analysis using a cohort of 10761 apparently healthy Chinese adults who underwent comprehensive health checkups including abdominal ultrasonography. In the setting of NAFLD and non-NAFLD, although men had significantly higher levels of atherogenic lipids as indicated by higher levels of triglyceride, triglyceride/HDL-cholesterol, and lower levels of HDL-cholesterol and worsen renal function as indicated by higher levels of creatinine and lower levels of estimated glomerular filtration rate (eGFR) than female counterparts, men with NAFLD showed greater relative differences in atherogenic lipids and deteriorated renal function than women with NAFLD when compared with their non-NAFLD counterparts. The interactions between sex and NAFLD on triglyceride, HDL-cholesterol, triglyceride/HDL-cholesterol, creatinine, and eGFR were statistically significant (P < 0.05). In the multivariate Logistic regression analyses, we observed a stronger association of TG with NAFLD and comparable associations of eGFR or HDL-C with NAFLD in men compared with women.

CONCLUSION

There was greater adverse influence of NAFLD per se on triglyceride, and triglyceride/HDL-cholesterol in men compared with women. The greater adverse influence of NAFLD per se on HDL-C and eGFR in men compared with women probably related to the gender differences in TG levels.

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.

Novel plasma biomarkers associated with liver disease severity in adults with nonalcoholic fatty liver disease

Despite the high prevalence of nonalcoholic fatty liver disease (NAFLD), therapeutic options and noninvasive markers of disease activity and severity remain limited. We investigated the association between plasma biomarkers and liver histology in order to identify markers of disease activity and severity in patients with biopsy-proven NAFLD. Thirty-two plasma biomarkers chosen a priori as possible discriminators of NAFLD were measured in participants enrolled in the Nonalcoholic Steatohepatitis (NASH) Clinical Research Network. Dichotomized histologic outcomes were evaluated using centrally read biopsies. Biomarkers with statistically significant associations with NAFLD histology were evaluated in multivariable models adjusted for clinical factors. Of 648 participants (74.4% white, 61.7% female, mean age 47.7 years), 58.0% had definite NASH, 55.5% had mild/no fibrosis (stage 0-1), and 44.4% had significant fibrosis (stage 2-4). Increased activated plasminogen activator inhibitor 1 had a strong association with definite NASH compared to not NASH or borderline NASH in multivariable analysis (odds ratio = 1.20, 95% confidence interval 1.08-1.34, P < 0.001). Biomarkers associated with significant fibrosis (versus mild/no fibrosis) in multivariable analysis included higher levels of interleukin-8, monocyte chemoattractant protein-1, resistin, soluble interleukin-1 receptor I, soluble interleukin-2 receptor alpha, and tumor necrosis factor alpha and lower levels of insulin-like growth factor 2.

CONCLUSIONS

Specific plasma biomarkers are significantly associated with disease activity and severity of fibrosis in NAFLD and are potentially valuable tools for noninvasive stratification of patients with NAFLD and identification of targets for therapeutic intervention. (Hepatology 2017;65:65-77).

Nonalcoholic Fatty Liver Disease: The New Complication of Type 2 Diabetes Mellitus

Nonalcoholic fatty liver disease (NAFLD) is increasingly common in patients with type 2 diabetes mellitus (T2DM), with an estimated prevalence of 60% to 80%. The relationship of NAFLD and T2DM is complex, with each condition negatively affecting the other. Although NAFLD is associated with more metabolic and cardiovascular complications and worse hyperglycemia, T2DM accelerates the progression of liver disease in NAFLD. Despite the high prevalence and serious clinical implications, NAFLD is usually overlooked in clinical practice. This article focuses on understanding the relationship between NAFLD and T2DM, to provide better care for these complex patients.

Association between metabolic syndrome and liver histology among NAFLD patients without diabetes

BACKGROUND

Metabolic syndrome (MetS) and obesity are associated with non-alcoholic fatty liver disease (NAFLD). The aim of this observational study was to examine the relationship of MetS and a diagnosis of non-alcoholic steatohepatitis (NASH) in patients without diabetes in the NASH Clinical Research Network (CRN).

METHODS

Clinical, demographic, histological, laboratory and anthropometric data were collected on 356 adult patients without diabetes with NAFLD. Obesity was defined as body mass index ≥30.0. MetS was determined using the National Cholesterol Education Program-Adult Treatment Panel III (NCEP ATPIII) 2001 criteria to include 3 or more of the following: increased waist circumference, elevated triglycerides, reduced high-density lipoprotein cholesterol, hypertension and elevated fasting blood glucose.

RESULTS

Most patients were obese (71%) and had MetS (67%). Obesity was more prevalent among patients with MetS (80% vs 52%; p≤0.001). Markers of insulin resistance such as homoeostasis model assessment of insulin resistance (6.5 vs 4.9, p≤0.001) were higher among those with MetS compared with those without MetS. Histologically, patients without MetS had higher hepatocellular (p=0.04) and reticuloendothelial system iron (p=0.04). Patients with MetS were more likely to have severe hepatic steatosis (p=0.04) and chronic portal inflammation (p=0.01). On multiple logistic regression analysis, patients with definite NASH were almost 2.5 times more likely to have MetS than those without definite NASH (OR=2.41, p=0.01).

CONCLUSIONS

MetS is common in patients without diabetes with NAFLD and is associated with greater insulin resistance, hepatic steatosis and portal inflammation. While patients without MetS have greater iron overload, patients with MetS may have an increased propensity to have NASH. Therefore, presence of MetS in patients without diabetes with NAFLD may serve as a potential criterion for liver biopsy.

TRIAL REGISTRATION NUMBER

NCT00063622; Pre-results.

The independent predictors of non-alcoholic steatohepatitis and its individual histological features.: Insulin resistance, serum uric acid, metabolic syndrome, alanine aminotransferase and serum total cholesterol are a clue to pathogenesis and candidate targets for treatment

AIM

The diagnosis of non-alcoholic steatohepatitis (NASH) is based on the individual histological features: steatosis, lobular inflammation and ballooning. Non-alcoholic fatty liver disease (NAFLD) activity score (NAS ≥ 5) is used in clinical trials. Fibrosis dictates long-term NAFLD prognosis. Recently, more-than-mild portal inflammation has raised interest as a marker of NAFLD severity. We assessed the independent predictors of: (I) individual histological lesions of NASH; (II) diagnosis of NASH; (III) significant (stage ≥2) and advanced (stage ≥3) fibrosis; and (IV) more-than-mild portal inflammation.

METHODS

Data from 118 consecutive biopsy-proven NAFLD patients observed at our institution were retrospectively analyzed.

RESULTS

At stepwise multivariate logistic regression analyses, independent predictors were as follows. For the individual histological features of NASH: insulin resistance (IR), assessed with Homeostasis Model Assessment-IR (HOMA-IR), serum uric acid (SUA) and serum total cholesterol (TCH) for moderate-to-severe steatosis; waist circumference (waist), HOMA-IR and TCH for lobular inflammation; waist, HOMA-IR, metabolic syndrome (MS), serum alanine aminotransferase (ALT), SUA and TCH for ballooning. For NASH diagnosis: waist, HOMA-IR, MS, ALT, SUA and TCH (Brunt et al.'s classification); ALT, SUA and TCH for NAS ≥ 5. For significant and advanced fibrosis, respectively: waist, MS and ALT; age, platelets, HOMA-IR, diabetes and TCH. For more-than-mild portal inflammation: serum aspartate aminotransferase (AST), serum iron, NAS ≥ 5 and significant liver fibrosis.

CONCLUSION

HOMA-IR, SUA, MS, ALT and TCH are independent predictors of NASH and its individual histological lesions, notably including fibrosis. Based on our findings, these factors should be considered major pathogenic drivers of NASH and, by inference, potential targets for treatment.

Pentoxifylline ameliorates non-alcoholic fatty liver disease in hyperglycaemic and dyslipidaemic mice by upregulating fatty acid β-oxidation

Nonalcoholic fatty liver disease (NAFLD), which includes simple steatosis, steatohepatitis, fibrosis, and cirrhosis, is characterised by abnormal fat accumulation in the liver in the absence of excessive alcohol intake. In patients with type 2 diabetes (T2D), concurrent NAFLD might increase the risk of chronic kidney disease and the mortality rate. Although several studies have examined the effectiveness of pentoxifylline (PTX) in NAFLD treatment, no results are available to verify the effectiveness of PTX in treating T2D associated with NAFLD. In this study, we developed a combined high-fat diet-induced obesity and low-dose streptozocin-induced hyperglycaemia mouse model to mimic the concurrent NAFLD and T2D pathological condition. By combining physiological assessments, pathological examinations, metabolomics studies on blood, urine, and liver, and measurements of gene and protein expression, we elucidated the effectiveness and the underlying mechanism of action of PTX in the hyperglycaemic and dyslipidaemic mice. Our results revealed that PTX ameliorated NAFLD in the hyperglycaemic and dyslipidaemic mice by upregulating fatty acid β-oxidation. Furthermore, the glycolysis pathway and branched-chain amino acid-related pathways in these mice were restored by PTX.

Association of noninvasive quantitative decline in liver fat content on MRI with histologic response in nonalcoholic steatohepatitis

BACKGROUND

Magnetic resonance imaging-estimated proton-density-fat-fraction (MRI-PDFF) has been shown to be a noninvasive, accurate and reproducible imaging-based biomarker for assessing steatosis and treatment response in nonalcoholic steatohepatitis (NASH) clinical trials. However, there are no data on the magnitude of MRI-PDFF reduction corresponding to histologic response in the setting of a NASH clinical trial. The aim of this study was to quantitatively compare the magnitude of MRI-PDFF reduction between histologic responders versus histologic nonresponders in NASH patients.

METHODS

This study is a secondary analysis of the MOZART trial, which included 50 patients with biopsy-proven NASH randomized to ezetimibe 10 mg/day orally or placebo for 24 weeks. The primary aim was to perform a head-to-head comparative analysis of histologic responders [defined as a ⩾2-point reduction in the nonalcoholic fatty liver disease (NAFLD) Activity Score (NAS) without worsening fibrosis] versus nonresponders, and the corresponding quantitative change in liver fat content measured via MRI-PDFF.

RESULTS

Of the 35 patients who underwent paired liver biopsy and MRI-PDFF assessment at the beginning and end of treatment, 10 demonstrated a histologic response. Compared with histologic nonresponders, histologic responders had a statistically significant reduction in MRI-PDFF of -4.1% ± 4.9 versus -0.6 ± 4.1 (p < 0.04) with a mean relative percent change of -29.3% ± 33.0 versus +2.0% ± 24.0 (p < 0.004), respectively.

CONCLUSIONS

Utilizing paired MRI-PDFF and liver histology data, we demonstrate that a relative reduction of 29% in liver fat on MRI-PDFF is associated with a histologic response in NASH. After external validation by independent research groups, these results can be incorporated into designing future NASH clinical trials, especially those utilizing change in hepatic fat quantified by MRI-PDFF, as a treatment endpoint.

Association between sonographic diagnosis of fatty liver with histopathologic abnormalities and liver biopsy findings in middle age patient with non-alcoholic fatty liver disease

Background:

Liver biopsy is required to diagnose non-alcoholic steatohepatitis in patients with suspected non-alcoholic fatty liver disease (NAFLD). This study aimed to examine the relationship between sonographic diagnosis of fatty liver with histopathologic abnormalities and liver biopsy findings in patient with NAFLD.

Materials and Methods:

In this cross-sectional study, a total of 180 patients, with an age range of 18-60 year old, with NAFLD based on ultrasonograghic findings were evaluated. Age, sex, body mass index, diabetes mellitus, hypertension, family history of liver disease and laboratory parameters recorded for all patients. Hence, grade of steatosis and stage of fibrosis were evaluated by liver biopsy.

Results:

A total of 220 patients were enrolled. Liver biopsy was performed in 180 patients. Mean age was 43 ± 10.6 years old and 66% were male. Ultrasonograghic findings showed mild, moderate and severe NAFLD was define in 100 (55.5%), 72 (40%) and 8 (4.5%) of patients, respectively. Liver biopsies showed that steatosis scores of <5%, 5-33% and 33-66% was define in 56 (31%), 116 (64%) and 9 (5%) of patients, respectively. Furthermore, fibrosis was defined as follow; none 92 (51%), mild 68 (38%), moderate 11 (6%), bridging 5 (3%) and cirrhosis 3 (2%) patients. There was no statistically significant relationship between ultrasonograghic findings and steatosis scores (P = 0.44), but statistically significant relationship was found between ultrasonograghic findings and fibrosis stage (P = 0.017).

Conclusion:

Findings revealed that, in patients with NAFLD, ultrasonographic finding were not in associate to steatosis, but were in relation with fibrosis stage.

[Hepatic steatosis : Differential diagnostics and current aspects]

The frequency of non-alcoholic fatty liver disease (NAFLD) has continously increased over the last few decades in parallel with the increasing prevalence of metabolic syndrome. With the increasing frequency of obesity and type 2 diabetes an increase in non-alcoholic steatohepatitis (NASH) is also to be expected. The NASH-associated liver cirrhosis and primary hepatocellular carcinoma (HCC) are indications for liver transplantation (LTX), which is gaining importance in Germany. In contrast, liver cirrhosis as a result of alcoholic steatohepatitis (ASH) is already the leading cause for LTX in Germany. A significant number of patients with ASH cirrhosis develop HCC. Less common causes of hepatic steatosis are secondary and include chemotherapy-associated steatohepatitis (CASH). In this article the causes, diagnostics and novel therapeutic approaches for the various forms of steatosis are discussed.

Liver stiffness measurement using acoustic radiation force impulse elastography in hepatitis C virus-infected patients with a sustained virological response

BACKGROUND

Acoustic radiation force impulse (ARFI) elastography is a non-invasive method for measuring liver stiffness. However, there are no reports evaluating the value of ARFI elastography for liver fibrosis in chronic hepatitis C patients with a sustained virological response (SVR).

AIM

To investigate the diagnostic performance of ARFI elastography for the assessment of liver fibrosis in hepatitis C virus (HCV) infected patients with an SVR.

METHODS

In this prospective study, we enrolled 336 patients: 121 HCV patients with an SVR (44.6% women) and 215 patients with HCV (47.9% women). ARFI elastography measurements of all patients were performed on the same day of liver biopsy.

RESULTS

The diagnostic accuracies, expressed as areas under the receiver operating characteristic curves for ARFI elastography, in HCV patients with an SVR and those in patients with HCV were 0.818 and 0.875 for the diagnosis of significant fibrosis (≥F2), 0.909 and 0.888 for the diagnosis of severe fibrosis (≥F3), and 0.981 and 0.890 for the diagnosis of liver cirrhosis (F4), respectively. The optimum cut-off values for ARFI elastography were 1.26 m/s for ≥F2, 1.31 m/s for ≥F3 and 1.49 m/s for F4 in HCV patients with an SVR. The liver stiffness values were lower in patients with SVR compared with those in patients with HCV at the same stage of fibrosis. The liver stiffness values were affected by the necroinflammatory activity and the time after SVR.

CONCLUSION

Acoustic radiation force impulse elastography is an acceptable method for predicting the severity of fibrosis in patients with hepatitis C virus and a sustained viral response.

Epidemiology and natural history of non-alcoholic fatty liver disease

Non-alcoholic steatohepatitis (NASH) is part of the spectrum of non-alcoholic fatty liver disease (NAFLD) that leads to progressive liver disease and presents a growing challenge to public health. Because of the increased prevalence of metabolic syndrome and obesity, NAFLD and NASH have expanded to a substantial extent. In NASH patients, advanced fibrosis is the major predictor of morbidity and liver-related mortality, and an accurate diagnosis of NASH is mandatory. Although there is currently no validated test of serum biomarkers available to diagnose NASH, and histologic evaluation with a liver biopsy remains the gold standard, screening for fibrosis is recommended in patients with suspicion of NASH. Clinical prediction models and serum biomarkers for advanced fibrosis have relatively good negative predictive value and can be useful for screening. Also, transient elastography is increasingly available to estimate fibrosis in NASH. Therefore, due to the lack of a reliable and accepted non-invasive diagnostic modality, screening for NASH in the general population is not currently recommended. Better understanding of the natural history of NASH is needed to evaluate the utility and cost-effectiveness of screening.

A longer duration of estrogen deficiency increases fibrosis risk among postmenopausal women with nonalcoholic fatty liver disease

Postmenopausal women with nonalcoholic steatohepatitis are at an increased risk of hepatic fibrosis compared with premenopausal women. Whether duration of estrogen deficiency in postmenopausal state dictates an individual's fibrosis risk remains uninvestigated. We assessed the associations of age at menopause and time from menopause with fibrosis severity in postmenopausal women with nonalcoholic fatty liver disease. Data from 488 postmenopausal women with (1) histologic diagnosis of nonalcoholic fatty liver disease and (2) self-reported information on age at menopause were analyzed. The associations of premature menopause (age at menopause of <40 years) and time from menopause (age at study enrollment - age at menopause, years) with fibrosis severity (stage 0-4) were assessed using multiple ordinal logistic regression models with and without adjusting for clinical confounders. Among the participants (age at menopause 43.7 ± 8.6 years), women with premature menopause (29.3%) were younger at enrollment (P < 0.001) and used hormone replacement therapy more often (P < 0.003). After adjusting for age at enrollment, race, waist circumference standardized by body mass index, current smoking, current alcohol use, hypertension, diabetes/impaired fasting glucose, homeostatic model assessment of insulin resistance, and hormone replacement therapy, premature menopause was associated with an increased likelihood of having more severe fibrosis (adjusted cumulative odds ratio = 1.9, 95% confidence interval 1.3-2.7, P = 0.001), while time from menopause was directly associated with an increased likelihood of having more severe fibrosis (adjusted cumulative odds ratio for 5-year unit = 1.2, 95% confidence interval 1.1-1.3, P = 0.002).

CONCLUSION

Duration of estrogen deficiency in postmenopausal state confers fibrosis risk among postmenopausal women with nonalcoholic fatty liver disease. (Hepatology 2016;64:85-91).

Prevalence of Non-alcoholic Fatty Liver Disease and Steatohepatitis Risk Factors in Patients Undergoing Bariatric Surgery

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) associated with obesity comprises pathological changes ranging from steatosis to steatohepatitis; these can evolve to cirrhosis and hepatocellular carcinoma.

OBJECTIVES

The objectives of this study are to assess the prevalence of and predictive markers for steatohepatitis in obese patients undergoing bariatric surgery.

METHODS

A prospective study of 184 morbidly obese patients undergoing bariatric surgery formed the study cohort. Patients taking potentially hepatotoxic medications and those with viral diseases and a history of excessive alcohol consumption were excluded. Liver biopsies were performed during surgery with a "Trucut" needle. Patients were classified into the following groups according to the histopathological findings: normal, steatosis, mild steatohepatitis, and moderate-severe steatohepatitis. Factors associated with steatohepatitis were evaluated using logistic regression. p values <0.05 were considered significant.

RESULTS

The prevalence of NAFLD was 84 % (steatosis, 22.0 %; mild steatohepatitis, 30.8 %; moderate-severe steatohepatitis, 32.0 %). Independent predictive factors for steatohepatitis were age (odds ratio (OR), 1.05; 95 % confidence interval (CI), 1.01-1.09; p = 0.011), waist circumference (OR, 1.03; 95 % CI, 1.00-1.06; p = 0.021), serum alanine aminotransferase (ALT) levels (OR, 1.04; 95 % CI, 1.01-1.08; p = 0.005), and serum triglyceride levels (OR, 1.01; 95 % CI, 1.00-1.01; p = 0.042). Score values for each predictor were derived from regression coefficients and odds ratio, and a total (risk) score was obtained from the sum of the points to evaluate the probability of having steatohepatitis.

CONCLUSION

Age, waist circumference, serum ALT levels, and serum triglyceride levels are efficient and non-invasive predictive markers for the diagnosis and management of steatohepatitis in morbidly obese patients.

Quantification of hepatic and visceral fat by CT and MR imaging: relevance to the obesity epidemic, metabolic syndrome and NAFLD

Trends in obesity have continued to increase in the developed world over the past few decades, along with related conditions such as metabolic syndrome, which is strongly associated with this epidemic. Novel and innovative methods to assess relevant obesity-related biomarkers are needed to determine the clinical significance, allow for surveillance and intervene if appropriate. Aggregations of specific types of fat, specifically hepatic and visceral adiposity, are now known to be correlated with these conditions, and there are a variety of imaging techniques to identify and quantify their distributions and provide diagnostic information. These methods are particularly salient for metabolic syndrome, which is related to both hepatic and visceral adiposity but currently not defined by it. Simpler non-specific fat measurements, such as body weight, abdominal circumference and body mass index are more frequently used but lack the ability to characterize fat location. In addition, non-alcoholic fatty liver disease (NAFLD) is a related condition that carries relevance not only for obesity-related diseases but also for the progression of the liver-specific disease, including non-alcoholic steatohepatitis and cirrhosis, albeit at a much lower frequency. Recent CT and MRI techniques have emerged to potentially optimize diagnosing metabolic syndrome and NAFLD through non-invasive quantification of visceral fat and hepatic steatosis with high accuracy. These imaging modalities should aid us in further understanding the relationship of hepatic and visceral fat to the obesity-related conditions such as metabolic syndrome, NAFLD and cardiovascular disease.

Vitamin D Deficiency Is Associated With Increased Risk of Non-alcoholic Steatohepatitis in Adults With Non-alcoholic Fatty Liver Disease: Possible Role for MAPK and NF-κB?

OBJECTIVES

The objective of this study was to determine the relationship of serum vitamin D deficiency (VDD) to histologic features of non-alcoholic fatty liver disease (NAFLD), and associated demographic, clinical, laboratory, and transcriptomic data in the well-characterized Non-alcoholic Steatohepatitis Clinical Research Network (NASH CRN) cohort.

METHODS

Serum vitamin D 25(OH)D (VD) was quantified by liquid chromatography-tandem mass spectrometry in 190 adults (>18 years) with biopsy-proven NAFLD. Subjects were categorized according to their level of VD as either sufficient (>30 ng/ml), insufficient (≥20≤30 ng/ml), or deficient (VDD; <20 ng/ml). Multivariable logistic regression was used to investigate the association of VDD and the presence of definite NASH and individual histological features of NAFLD after adjusting for age, sex, race, body mass index, alanine aminotransferase, and diabetes status. Hepatic transcriptomic data was compared between VDD and non-VDD subjects.

RESULTS

VDD was present in 55% of subjects and was independently associated with definitive NASH (odds ratio (OR) 3.15, 95% confidence interval (CI), 1.62-6.15, P=0.001), increased lobular inflammation (OR=1.98, 95% CI, 1.08-3.61, P=0.026), more ballooning (OR=2.38, 95% CI, 1.32-4.30, P=0.004), and the presence of fibrosis (OR=2.32, 95% CI, 1.13-4.77, P=0.022). There was a significant inverse relationship between lower levels of serum resistin and increased VD level category (P=0.013). The KRT10, SEMA3B, SNORD3C, ARSD, and IGKV4-1 genes were differentially expressed (false discovery rate <0.05) between VDD and non-VDD subjects. Gene ontology and pathway analysis suggest activation of the mitogen-activated protein kinase and nuclear factor-κB pathways in VDD NAFLD subjects.

CONCLUSIONS

VDD is prevalent among US adult NAFLD patients and is independently associated with a definitive diagnosis of NASH and increased histological severity. Novel associations in proinflammatory pathways were identified, which suggest the mechanism for VDD in the pathogenesis of NASH and support dietary and/or lifestyle modifications to increase vitamin D levels in these patients.

The Natural Course of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease in the world, paralleling the epidemic of obesity and Type 2 diabetes mellitus (T2DM). NAFLD exhibits a histological spectrum, ranging from “bland steatosis” to the more aggressive necro-inflammatory form, non-alcoholic steatohepatitis (NASH) which may accumulate fibrosis to result in cirrhosis. Emerging data suggests fibrosis, rather than NASH per se, to be the most important histological predictor of liver and non-liver related death. Nevertheless, only a small proportion of individuals develop cirrhosis, however the large proportion of the population affected by NAFLD has led to predictions that NAFLD will become a leading cause of end stage liver disease, hepatocellular carcinoma (HCC), and indication for liver transplantation. HCC may arise in non-cirrhotic liver in the setting of NAFLD and is associated with the presence of the metabolic syndrome (MetS) and male gender. The MetS and its components also play a key role in the histological progression of NAFLD, however other genetic and environmental factors may also influence the natural history. The importance of NAFLD in terms of overall survival extends beyond the liver where cardiovascular disease and malignancy represents additional important causes of death.

Nonalcoholic Fatty Liver Disease: Lipids and Insulin Resistance

Obesity and its major comorbidities, including type 2 diabetes mellitus, nonalcoholic fatty liver disease (NAFLD), obesity cardiomyopathy, and certain cancers, have caused life expectancy in the United States to decline in recent years. Obesity is the increased accumulation of triglycerides (TG), which are synthesized from glycerol and long-chain fatty acids (LCFA) throughout the body. LCFA enter adipocytes, hepatocytes, and cardiomyocytes via specific, facilitated transport processes. Metabolism of increased cellular TG content in obesity may lead to comorbidities such as NAFLD and cardiomyopathy. Better understanding of LCFA transport processes may lead to successful treatment of obesity and NAFLD.

Histology of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis in Adults and Children

Nonalcoholic fatty liver disease (NAFLD) is the liver disease associated with obesity, diabetes, and the metabolic syndrome. Although steatosis is a key histologic feature, liver biopsies of patients with NAFLD can show a wide range of findings. Nonalcoholic steatohepatitis (NASH) is a progressive subtype of NAFLD first defined by analogy to alcoholic hepatitis. Young children may have an alternate pattern of progressive NAFLD characterized by a zone 1 distribution of steatosis, inflammation, and fibrosis. Several grading and staging systems exist, but all require adequate biopsies. Although NASH generally shows fibrosis progression over time, some patients show regression of disease.

Comparison of liver enzymes level and sonographic findings value with liver biopsy findings in nonalcoholic fatty liver disease patients

Background:

This study aimed to examine the relationship between sonographic diagnosis of fatty liver and liver enzyme level with histopathologic abnormalities and liver biopsy findings in patient with the nonalcoholic fatty liver disease (NAFLD).

Materials and Methods:

This cross-sectional study conducted on 109 patients with diagnosed and under treatment NAFLD refer to Gastroenterology Clinics of AL Zahra Hospital in Isfahan, Iran. Age, sex, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) level recorded for all patients. Liver ultrasonography was performed for all patients. Steatosis grading and fibrosis stage were evaluated by liver biopsy.

Results:

We enrolled 109 subjects with NAFLD who had an indication for liver biopsy and met inclusion criteria of our study. Of these, 78 subjects (71.6%) were male and 31 subjects (28.4) were female. Mean age was 40.17 ± 11.01 years old. Our results showed there was a statistically significant relationship between ultrasonographic findings and histologic findings based on biopsy. There was statistically significant relationship between liver enzyme (ALT, AST and ALP) level and ultrasonographic findings, but there was no significant relationship between AST and ALT level and histologic findings, but the relationship between ALP level and histologic findings (steatosis and fibrosis) was statistically significant (P = 0.01).

Conclusion:

Ultrasonographic finding may be can use to identify nonalcoholic steatohepatitis and stage of fibrosis in patients with NAFLD, but AST and ALT level is not reliable screening test to identify stage of fibrosis and steatosis in these patients. Therefore, liver biopsy remains the gold standard for establishing steatohepatitis and advanced fibrosis in patients with NAFLD.

Drosophila tools and assays for the study of human diseases

Many of the internal organ systems of Drosophila melanogaster are functionally analogous to those in vertebrates, including humans. Although humans and flies differ greatly in terms of their gross morphological and cellular features, many of the molecular mechanisms that govern development and drive cellular and physiological processes are conserved between both organisms. The morphological differences are deceiving and have led researchers to undervalue the study of invertebrate organs in unraveling pathogenic mechanisms of diseases. In this review and accompanying poster, we highlight the physiological and molecular parallels between fly and human organs that validate the use of Drosophila to study the molecular pathogenesis underlying human diseases. We discuss assays that have been developed in flies to study the function of specific genes in the central nervous system, heart, liver and kidney, and provide examples of the use of these assays to address questions related to human diseases. These assays provide us with simple yet powerful tools to study the pathogenic mechanisms associated with human disease-causing genes.

Nonalcoholic fatty liver disease is associated with cognitive function in adults

OBJECTIVE

We hypothesized that nonalcoholic fatty liver disease (NAFLD) is independently associated with cognitive impairment in a representative sample of the general US population regardless of the presence of cardiovascular disease (CVD) or its risk factors.

METHODS

This was a cross-sectional study of 4,472 adults aged 20-59 years who participated in the Third National Health and Nutritional Examination Survey. The participants underwent assessment of liver enzyme activity and hepatic steatosis by ultrasound, and underwent cognitive evaluation using the following computer-administered tests: the Simple Reaction Time Test (SRTT), the Symbol-Digit Substitution Test (SDST), and the Serial Digit Learning Test (SDLT). We defined NAFLD as moderate/severe steatosis as determined by ultrasound in the absence of hepatitis B or C or excessive alcohol consumption. We used multiple linear regression models to examine the association between NAFLD and cognitive function while controlling for potential confounders.

RESULTS

Participants with NAFLD showed lower overall performance on the SDLT (β = 0.726, 95% confidence interval [CI] 0.105-1.347), while associations with SRTT and SDST did not reach significance. Increased activity of the liver enzymes alanine aminotransferase (β = 0.018, 95% CI 0.006-0.030) and aspartate aminotransferase (β = 0.021, 95% CI 0.005-0.037) correlated with lower performance on the SDLT, while increased alanine aminotransferase was also correlated with lower performance in the SDST (β = 0.002, 95% CI 0.0001-0.004).

CONCLUSIONS

NAFLD was independently associated with lower cognitive performance independent of CVD and its risk factors. Given the scarcity of risk factors associated with age-related cognitive decline, these findings may have significant implications.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a disorder characterized by excess accumulation of fat in hepatocytes (nonalcoholic fatty liver (NAFL)); in up to 40% of individuals, there are additional findings of portal and lobular inflammation and hepatocyte injury (which characterize nonalcoholic steatohepatitis (NASH)). A subset of patients will develop progressive fibrosis, which can progress to cirrhosis. Hepatocellular carcinoma and cardiovascular complications are life-threatening co-morbidities of both NAFL and NASH. NAFLD is closely associated with insulin resistance; obesity and metabolic syndrome are common underlying factors. As a consequence, the prevalence of NAFLD is estimated to be 10-40% in adults worldwide, and it is the most common liver disease in children and adolescents in developed countries. Mechanistic insights into fat accumulation, subsequent hepatocyte injury, the role of the immune system and fibrosis as well as the role of the gut microbiota are unfolding. Furthermore, genetic and epigenetic factors might explain the considerable interindividual variation in disease phenotype, severity and progression. To date, no effective medical interventions exist that completely reverse the disease other than lifestyle changes, dietary alterations and, possibly, bariatric surgery. However, several strategies that target pathophysiological processes such as an oversupply of fatty acids to the liver, cell injury and inflammation are currently under investigation. Diagnosis of NAFLD can be established by imaging, but detection of the lesions of NASH still depend on the gold-standard but invasive liver biopsy. Several non-invasive strategies are being evaluated to replace or complement biopsies, especially for follow-up monitoring.

Heritability of Hepatic Fibrosis and Steatosis Based on a Prospective Twin Study

BACKGROUND & AIMS

Little is known about the heritability of hepatic fibrosis, and the heritability of hepatic steatosis has not been assessed systematically in adults. We investigated the heritability of hepatic fibrosis and steatosis in a community-dwelling twin cohort.

METHODS

We performed a cross-sectional analysis of a cohort of well-characterized twins residing in Southern California including 60 pairs of twins (42 monozygotic and 18 dizygotic; average age, 45.7 ± 22.1 y; average body mass index, 26.4 ± 5.7 kg/m(2)). We collected data on medical history, physical examinations, fasting laboratory test results, and liver health; all participants underwent an advanced magnetic resonance imaging (MRI) examination of the liver from January 2012 through January 2015. Hepatic steatosis was quantified noninvasively by MRI and determined based on the proton-density fat fraction (MRI-PDFF); liver fibrosis was measured based on stiffness measured by magnetic resonance elastography.

RESULTS

Twenty-six of the 120 subjects (21.7%) had nonalcoholic fatty liver disease (defined as MRI-PDFF ≥ 5% after exclusion of other causes of hepatic steatosis). The presence of hepatic steatosis correlated between monozygotic twins (r(2) = 0.70; P < .0001) but not between dizygotic twins (r(2) = 0.36; P = .2). The level of liver fibrosis also correlated between monozygotic twins (r(2) = 0.48; P < .002) but not between dizygotic twins (r(2) = 0.12; P = .7). In multivariable models adjusted for age, sex, and ethnicity, the heritability of hepatic steatosis (based on MRI-PDFF) was 0.52 (95% confidence interval, 0.31-0.73; P < 1.1 × 10(-11)) and the heritability of hepatic fibrosis (based on liver stiffness) was 0.5 (95% confidence interval, 0.28-0.72; P <6.1 × 10(-11)).

CONCLUSIONS

A study of twins provides evidence that hepatic steatosis and hepatic fibrosis are heritable traits.

Murine models provide insight to the development of non-alcoholic fatty liver disease

Associated with the obesity epidemic, non-alcoholic fatty liver disease (NAFLD) has become the leading liver disease in North America. Approximately 30 % of patients with NAFLD may develop non-alcoholic steatohepatitis (NASH) that can lead to cirrhosis and hepatocellular carcinoma (HCC). Frequently animal models are used to help identify underlying factors contributing to NAFLD including insulin resistance, dysregulated lipid metabolism and mitochondrial stress. However, studying the inflammatory, progressive nature of NASH in the context of obesity has proven to be a challenge in mice. Although the development of effective treatment strategies for NAFLD and NASH is gaining momentum, the field is hindered by a lack of a concise animal model that reflects the development of liver disease during obesity and the metabolic syndrome. Therefore, selecting an animal model to study NAFLD or NASH must be done carefully to ensure the optimal application. The most widely used animal models have been reviewed highlighting their advantages and disadvantages to studying NAFLD and NASH specifically in the context of obesity.

Hyperuricemia Inversely Correlates with Disease Severity in Taiwanese Nonalcoholic Steatohepatitis Patients

BACKGROUND & AIMS

Asians are more susceptible to non-alcoholic steatohepatitis (NASH) as well as metabolic disorder than other ethnicities. We aimed to assess the interaction between metabolic factors and fibrosis in Taiwanese NASH patients.

METHODS

A total of 130 biopsy-proven Taiwanese NASH patients (94 males, age = 43.0 ± 13.0 years) were consecutively enrolled. Their demographic, metabolic profiles and histopathological manifestations were analyzed.

RESULTS

Twenty-four (18.5%) NASH patients were non-obese. Thirty-three (25.4%) patients had significant fibrosis (F2) or more: 22 (16.9%) patients were of F2, whilst 11 (8.5%) patients were of advanced fibrosis (F3-4). The prevalence of metabolic syndrome, diabetes and hypertension were 60.8%, 39.4%, and 61.5%, respectively. There was a significant inverse correlation between hyperuricemia and fibrosis stages, ranging from 48.4% of F0-1, 33.3% of F2, and 9.1% of F3-4, respectively (P = 0.01, linear trend). Multivariate logistic regression analysis showed that a decreased serum albumin level (OR = 40.0, 95% CI = 4.5-300, P = 0.001) and normal uric acid level (OR = 5.6, 95% CI = 1.5-21.7, P = 0.01) were the significant factors associated with significant fibrosis.

CONCLUSIONS

Hyperuricemia inversely predicts fibrosis stages. Females might carry a more disease severity than males in Taiwanese NASH patients.

Noninvasive estimation of disease activity and liver fibrosis in nonalcoholic fatty liver disease using anthropometric and biochemical characteristics, including insulin, insulin resistance, and 13C-methionine breath test

OBJECTIVE

The purpose of this study was to noninvasively estimate disease activity and liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) using anthropometric and biochemical characteristics and the C-methionine breath test (MeBT).

METHODS

A total of 164 patients with histologically proven NAFLD and 56 healthy controls were included in the study. Anthropometric and biochemical analyses and the MeBT were performed on all patients and controls.

RESULTS

BMI; waist circumference; waist-hip ratio; transaminase, lipid, γ-glutamyl transpeptidase (GGT), glucose, and insulin levels; and insulin resistance were significantly higher in patients with NAFLD than in controls. The GGT level and the MeBT were independent predictors of nonalcoholic steatohepatitis (NASH). Fibrosis was correlated with GGT, bilirubin, cholesterol, and insulin levels, and the MeBT, but the test was the only independent predictor of significant fibrosis. Patients with simple steatosis had similar MeBT values as controls. The MeBT values were significantly lower in NASH and NASH-cirrhosis patients (P<0.001) compared with simple steatosis patients and controls. Patients with advanced fibrosis (F2-3) had significantly lower MeBT values than patients with mild fibrosis (F0-1; P<0.001). The area under the receiving operating characteristic curve for NASH and advanced fibrosis was estimated to be 0.95 in the total cohort.

CONCLUSION

This study indicates that anthropometric and biochemical parameters are insufficient for estimating the presence of NASH or the fibrosis stage. However, the MeBT is a suitable noninvasive method for accurately predicting which patients suffer from simple steatosis, NASH, or NASH-cirrhosis.

Association of the Nonalcoholic Hepatic Steatosis and Its Degrees With the Values of Liver Enzymes and Homeostasis Model Assessment-Insulin Resistance Index

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is among the most common chronic diseases of the modern world with a wide variety of factors including genetic, environmental and metabolic. The aim of this study was to verify the association between the degrees of hepatic steatosis at the abdominal ultrasound and the values of aminotransferases (aspartate aminotransferase (AST) and alanine transferase (ALT)), gamma glutamyl transpeptidase (GGT) and homeostasis model assessment-insulin resistance (HOMA-IR) index.

METHODS

A prospective, descriptive survey study, using a quantitative analytical examination, was conducted from July 2013 to July 2014. In the statistical analysis, values were expressed as median, first and third quartiles. We used the nonparametric Kruskal-Wallis test to compare the medians between the degrees of steatosis, adopted a statistical significance of 5% (P ≤ 0.05) and used the statistical program SPSS 22.0.

RESULTS

We diagnosed 233/800 (29.1%) patients with hepatic steatosis on routine ultrasound, and 65.7% were female. Regarding degrees, 119 had grade 1 (51.0%), 94 grade 2 (40.4%) and 20 grade 3 (8.6%). The median age of the patients with grade 1, 2 or 3 did not vary significantly (P > 0.05). The median body mass index (BMI), although clinically important because of its elevation, did not differ significantly (P > 0.05). ALT levels increased as the degree of hepatic steatosis has advanced as well as the levels of AST, GGT and HOMA-IR. AST values showed a greater association with the severity of fatty liver (P = 0.0001) than the ALT (P = 0.001).

CONCLUSIONS

ALT, AST, GGT and HOMA-IR are associated to the degrees of hepatic steatosis on ultrasound and can help in the selection of patients for the liver histological evaluation.

Prosteatotic genes are associated with unsaturated fat suppression of saturated fat-induced hepatic steatosis in C57BL/6 mice

Both high sugar and fat diets can induce prosteatotic genes, leading to obesity and obesity-associated diseases, including hepatic steatosis. Unsaturated fat/fatty acid (USFA) reduces high sugar-induced hepatic steatosis by inhibiting the induced prosteatotic genes. In contrast, it is still unclear how USFA ameliorates saturated fat/fatty acid (SFA)-induced hepatic steatosis. As sugar and fat have different transport and metabolic pathways, we hypothesized that USFA suppressed SFA-induced hepatic steatosis via a different set of prosteatotic genes. To test this, we implemented high SFA vs USFA diets and a control diet in C57BL/6 mice for 16 weeks. Severe hepatic steatosis was induced in mice fed the SFA diet. Among a nearly complete set of prosteatotic genes, only the stearoyl-coenzyme a desaturase 1 (Scd1), cluster of differentiation 36 (Cd36), and peroxisome proliferator-activated receptor γ (Pparγ) genes that were differentially expressed in the liver could contribute to SFA-induced steatosis or the alleviative effect of USFA. That is, the SFA diet induced the expression of Cd36 and Pparγ but not Scd1, and the USFA diet suppressed Scd1 expression and the induction of Cd36 and Pparγ. These findings were mainly recapitulated in cultured hepatocytes. The essential roles of SCD1 and CD36 were confirmed by the observation that the suppression of SCD1 and CD36 with small interfering RNA or drug treatment ameliorated SFA-induced lipid accumulation in hepatocytes. We thus concluded that SCD1, CD36, and PPARγ were essential to the suppression of SFA-induced hepatic steatosis by main dietary USFA, which may provide different therapeutic targets for reducing high-fat vs sugar-induced hepatic steatosis.

Increased abdominal fat levels measured by bioelectrical impedance are associated with histological lesions of nonalcoholic steatohepatitis

BACKGROUND/AIM

Abdominal fat is considered to play an important role in nonalcoholic fatty liver disease (NAFLD), although it is not adequately studied because abdominal fat levels cannot be estimated easily. In this study, associations between abdominal obesity, as assessed by abdominal bioelectrical impedance analysis (BIA), and the characteristics of patients with NAFLD were explored.

PATIENTS AND METHODS

Seventy-four consecutive NAFLD patients who underwent measurement of abdominal fat levels by BIA were included. Levels of abdominal fat 12.5 or less and more than 12.5 were considered to be average and increased, respectively.

RESULTS

The mean±SD BMI was 30±4 kg/m and the mean abdominal fat levels were 16±5, whereas 26% of patients had average abdominal fat levels. Patients with average compared with those with increased abdominal fat levels were more frequently women (50 vs. 12%, P=0.001), had lower BMI (27±3 vs. 31±4 kg/m, P<0.001), lower Homeostasis Model Assessment index (2.6±1.4 vs. 3.9±2.7, P=0.045), and lower median liver stiffness on transient elastography (5.3 vs. 6.8 kPa, P=0.025). In patients with available liver biopsy, steatohepatitis was present more frequently in patients with increased compared with average abdominal fat levels (78 vs. 38%, P=0.030) and in patients with BMI 30 or more compared with less than 30 kg/m (87 vs. 48%, P=0.033), but similar in patients with increased or normal waist circumference (67 vs. 56%, P=0.693).

CONCLUSION

Average levels of abdominal fat, as assessed by abdominal BIA, are mainly present in female patients with NAFLD and are associated with a lower degree of insulin resistance. Increased abdominal fat as assessed by BIA and obesity seem to represent strong risk factors for histological steatohepatitis.

Clinical Model for NASH and Advanced Fibrosis in Adult Patients With Diabetes and NAFLD: Guidelines for Referral in NAFLD

OBJECTIVE

Approximately 18 million people in the U.S. have coexisting type 2 diabetes and nonalcoholic fatty liver disease (NAFLD). It is not known who among these patients has nonalcoholic steatohepatitis (NASH) with advanced fibrosis. Therefore, we aimed to determine factors that are associated with both NASH and advanced fibrosis in patients with diabetes and NAFLD in order to identify who should be prioritized for referral to a hepatologist for further diagnostic evaluation and treatment.

RESEARCH DESIGN AND METHODS

This study was derived from the NASH Clinical Research Network studies and included 1,249 patients with biopsy-proven NAFLD (including a model development cohort of 346 patients and an independent validation cohort of 100 patients with type 2 diabetes as defined by the American Diabetes Association criteria). Outcome measures were presence of NASH or advanced fibrosis (stage 3 or 4) using cross-validated, by jackknife method, multivariable-adjusted area under the receiver operating characteristic curve (AUROC) and 95% CI.

RESULTS

The mean ± SD age and BMI of patients with diabetes and NAFLD was 52.5 ± 10.3 years and 35.8 ± 6.8 kg/m(2), respectively. The prevalence of NASH and advanced fibrosis was 69.2% and 41.0%, respectively. The model for NASH included white race, BMI, waist, alanine aminotransferase (ALT), Aspartate aminotransferase (AST), albumin, HbA1c, HOMA of insulin resistance, and ferritin with an AUROC of 0.80 (95% CI 0.75-0.84, P = 0.007). The specificity, sensitivity, negative predictive values (NPVs), and positive predictive values (PPVs) were 90.0%, 56.8%, 47.7%, and 93.2%, respectively, and the model correctly classified 67% of patients as having NASH. The model for predicting advanced fibrosis included age, Hispanic ethnicity, BMI, waist-to-hip ratio, hypertension, ALT-to-AST ratio, alkaline phosphatase, isolated abnormal alkaline phosphatase, bilirubin (total and direct), globulin, albumin, serum insulin, hematocrit, international normalized ratio, and platelet count with an AUROC of 0.80 (95% CI 0.76-0.85, P < 0.001). The specificity, sensitivity, NPV, and PPV were 90.0%, 57%, 75.1%, and 80.2%, respectively, and the model correctly classified 76.6% of patients as having advanced fibrosis. Results remained consistent for both models in the validation cohort. The proposed model performed better than the NAFLD fibrosis score in detecting advanced fibrosis.

CONCLUSIONS

Routinely available clinical variables can be used to quantify the likelihood of NASH or advanced fibrosis in adult diabetic patients with NAFLD. The clinical models presented can be used to guide clinical decision making about referrals of patients with diabetes and NAFLD to hepatologists.

Age impacts ability of aspartate-alanine aminotransferase ratio to predict advanced fibrosis in nonalcoholic Fatty liver disease

BACKGROUND AND AIM

While histological differences have been reported between pediatric and adult nonalcoholic fatty liver disease (NAFLD), potential age-related changes in serum transaminases and liver histology remain largely unexplored. Our study sought to investigate the clinical and histological characteristics of NAFLD across age.

METHODS

This was a prospective cross-sectional study of 502 biopsy-proven NAFLD patients. Clinical data were evaluated and compared among different age groups; group A (ages 18-44), B (ages 45-64), and C (≥ ages 65).

RESULTS

34.9, 56.0, and 9.1 % of the cohort were distributed among group A, B, and C, respectively. While the prevalence of nonalcoholic steatohepatitis (NASH) was comparable across age groups, the prevalence of advanced fibrosis increased with age (p = 0.000). Although the mean ALT progressively decreased with age; 87, 64, 56 U/L in group A, B, and C, respectively (p = 0.000), there was no difference in mean AST (p = 0.939) across age. The AST:ALT ratio (AAR) progressively increased from 0.7, 0.9, and 1.1 in group A, B, and C, respectively (p = 0.000). In group C, an AAR ≥ 1 was found in 74 and 40 % of patients with and without advanced fibrosis.

CONCLUSION

With advancing age, ALT levels progressively declined while AST levels remained stable, leading to a higher AAR. Although higher AAR is often used as a surrogate measure of advanced fibrosis, advancing age can also contribute to increased AAR. In fact, an AAR ≥ 1 was found in significant number of elderly patients without advanced fibrosis. Consequently, an increased AAR may be a function of decreasing ALT with age in addition to progressive fibrosis.

Nonalcoholic fatty liver disease: update on pathogenesis, diagnosis, treatment and the role of S-adenosylmethionine

Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease worldwide affecting over one-third of the population in the U.S. It has been associated with obesity, type 2 diabetes, hyperlipidemia, and insulin resistance and is initiated by the accumulation of triglycerides in hepatocytes. Isolated hepatic steatosis (IHS) remains a benign process, while a subset develops superimposed inflammatory activity and progression to nonalcoholic steatohepatitis (NASH) with or without fibrosis. However, the molecular mechanisms underlying NAFLD progression are not completely understood. Liver biopsy is still required to differentiate IHS from NASH as easily accessible noninvasive biomarkers are lacking. In terms of treatments for NASH, pioglitazone, vitamin E, and obeticholic acid have shown some benefit. All of these agents have potential complications associated with long-term use. Nowadays, a complex hypothesis suggests that multiple parallel hits are involved in NASH development. However, the 'key switch' between IHS and NASH remains to be discovered. We have recently shown that knocking out enzymes involved in S-adenosylmethionine (SAMe) metabolism, the main biological methyl donor in humans that is abundant in the liver, will lead to NASH development in mice. This could be due to the fact that a normal SAMe level is required to establish the proper ratio of phosphatidylethanolamine to phosphatidylcholine that has been found to be important in NAFLD progression. New data from humans have also suggested that these enzymes play a role in the pathogenesis of NAFLD and that some of SAMe cycle metabolites may serve as noninvasive biomarkers of NASH. In this review, we discuss the evidence of the role of SAMe in animal models and humans with NAFLD and how studying this area may lead to the discovery of new noninvasive biomarkers and possibly personalized treatment for NASH.

High Prevalence of Nonalcoholic Fatty Liver Disease in Patients With Type 2 Diabetes Mellitus and Normal Plasma Aminotransferase Levels

CONTEXT AND OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) and its more severe form with steatohepatitis (NASH) are common in patients with type 2 diabetes mellitus (T2DM). However, they are usually believed to largely affect those with elevated aminotransferases. The aim of this study was to determine the prevalence of NAFLD by the gold standard, liver magnetic resonance spectroscopy ((1)H-MRS) in patients with T2DM and normal aminotransferases, and to characterize their metabolic profile.

PARTICIPANTS AND METHODS

We recruited 103 patients with T2DM and normal plasma aminotransferases (age, 60 ± 8 y; body mass index [BMI], 33 ± 5 kg/m(2); glycated hemoglobin [A1c], 7.6 ± 1.3%). We measured the following: 1) liver triglyceride content by (1)H-MRS; 2) systemic insulin sensitivity (homeostasis model assessment-insulin resistance); and 3) adipose tissue insulin resistance, both fasting (as the adipose tissue insulin resistance index: fasting plasma free fatty acids [FFA] × insulin) and during an oral glucose tolerance test (as the suppression of FFA).

RESULTS

The prevalence of NAFLD and NASH were much higher than expected (50% and 56% of NAFLD patients, respectively). The prevalence of NAFLD was higher in obese compared with nonobese patients as well as with increasing BMI (P = .001 for trend). Higher plasma A1c was associated with a greater prevalence of NAFLD and worse liver triglyceride accumulation (P = .01). Compared with nonobese patients without NAFLD, patients with NAFLD had severe systemic (liver/muscle) and, particularly, adipose tissue (fasting/postprandial) insulin resistance (all P < .01).

CONCLUSIONS

The prevalence of NAFLD is much higher than previously believed in overweight/obese patients with T2DM and normal aminotransferases. Moreover, many are at increased risk of NASH. Physicians should have a lower threshold for screening patients with T2DM for NAFLD/NASH.

Comparative diagnostic accuracy of magnetic resonance elastography vs. eight clinical prediction rules for non-invasive diagnosis of advanced fibrosis in biopsy-proven non-alcoholic fatty liver disease: a prospective study

BACKGROUND

Two-dimensional magnetic resonance elastography (2D-MRE) is an advanced magnetic resonance method with high diagnostic accuracy for predicting advanced fibrosis in non-alcoholic fatty liver disease (NAFLD) patients. However, no prospective, head-to-head comparisons between 2D-MRE and clinical prediction rules (CPRs) have been performed in patients with biopsy-proven NAFLD.

AIM

To compare the diagnostic utility of 2D-MRE against that of eight CPRs (AST:ALT ratio, APRI, BARD, FIB-4, NAFLD Fibrosis Score, Bonacini cirrhosis discriminant score, Lok Index and NASH CRN model) for predicting advanced fibrosis in a prospective cohort with paired liver biopsy as the gold standard.

METHODS

This is a cross-sectional analysis of a prospective study of 102 patients (58.8% women) with biopsy-proven NAFLD, 2D-MRE and clinical research assessment within 90 days of biopsy. Receiver operating characteristic (ROC) analysis was performed to assess the performance of 2D-MRE and CPRs for predicting advanced fibrosis.

RESULTS

The mean (±s.d.) age and BMI were 51.3 (±14.0) years and 31.7 (±5.5) kg/m(2) respectively. 48, 26, 9, 13 and 6 patients had stage 0, 1, 2, 3 and 4 fibrosis respectively. The area under ROC curve (AUROC) was 0.957 for 2D-MRE and between 0.796 and 0.861 for the CPRs. FIB-4 was the best-performing CPR at predicting advanced fibrosis with AUROC of 0.861. In head-to-head comparisons using the DeLong test, 2D-MRE had significantly better AUROC (P < 0.05) than each CPR for predicting advanced fibrosis.

CONCLUSION

Compared to clinical prediction rules, 2D-MRE provides significantly higher accuracy for the diagnosis of advanced fibrosis in NAFLD patients.

Composite prognostic models across the non-alcoholic fatty liver disease spectrum: Clinical application in developing countries

Heterogeneity in clinical presentation, histological severity, prognosis and therapeutic outcomes characteristic of non-alcoholic fatty liver disease (NAFLD) necessitates the development of scientifically sound classification schemes to assist clinicians in stratifying patients into meaningful prognostic subgroups. The need for replacement of invasive liver biopsies as the standard method whereby NAFLD is diagnosed, graded and staged with biomarkers of histological severity injury led to the development of composite prognostic models as potentially viable surrogate alternatives. In the present article, we review existing scoring systems used to (1) confirm the presence of undiagnosed hepatosteatosis; (2) distinguish between simple steatosis and NASH; and (3) predict advanced hepatic fibrosis, with particular emphasis on the role of NAFLD as an independent cardio-metabolic risk factor. In addition, the incorporation of functional genomic markers and application of emerging imaging technologies are discussed as a means to improve the diagnostic accuracy and predictive performance of promising composite models found to be most appropriate for widespread clinical adoption.

Intravoxel Incoherent Motion Diffusion Weighted MR Imaging at 3.0 T: Assessment of Steatohepatitis and Fibrosis Compared with Liver Biopsy in Type 2 Diabetic Patients

Objective

To evaluate the capability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) to assess steatohepatitis and fibrosis determined by histopathology in type 2 diabetic patients.

Methods

Fifty-nine type 2 diabetic patients (49 women, 10 men; mean age, 54 ± 9 years) were submitted to liver biopsy for the evaluation of non-alcoholic fatty liver disease (NAFLD) and underwent DWI on a 3.0T MR system using 10 b values. Institutional approval and patient consent were obtained. Pure molecular-based (D), perfusion-related (D*), and vascular fraction (f) were calculated using a double exponential model and least squares curve fitting. D, D*, and f were compared between patients with and without steatohepatitis and between patients with and without fibrosis. The variables were compared by using the Ranksum test and Student t-test.

Results

Steatohepatitis was observed in 22 patients and fibrosis in 16 patients. A lower D median (0.70 s/mm² vs. 0.83 s/mm², p<0.05) and a lower D* median (34.39 s/mm² vs. 45.23 s/mm², p<0.05) were observed among those with steatohepatitis. A lower D median (0.70 s/mm² vs. 0.82 s/mm², p<0.05) and a lower D* median (35.01 s/mm² vs. 44.76 s/mm², p=0.05) were also observed among those with fibrosis.

Conclusion

IVIM-DWI has the potential to aid in the characterization of steatohepatitis and fibrosis.

Kupffer cells and hepatic lipid metabolism disorder

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disorder of our times in both developed and developing countries, which is associated with insulin resistance and genetic susceptibility. Simple steatosis, a seemingly innocent manifestation of early stage NAFLD, may progress into steatohepatitis and cirrhosis, which may even progress into hepatocellular carcinoma. Kupffer cells (KCs) constitute the first firewall of the liver, representing 80%-90% of all tissue macrophages in the body and taking part in various acute and chronic inflammatory reactions. It is deemed that the genesis and development of NAFLD are closely related to the chronic metabolic inflammation induced by KCs. KCs could be activated by lipids accumulated in the liver, and activated KCs participate in metabolic inflammation through releasing pro-inflammatory factors. In this review, we focus on recently uncovered aspects of the biochemical, immunological and molecular events that are responsible for the development and progression of this highly prevalent and potentially serious disease, and summarize the role of KCs in the pathogenesis of NAFLD.

Amount of hepatic fat predicts cardiovascular risk independent of insulin resistance among Hispanic-American adolescents

Background

Nonalcoholic fatty liver disease (NAFLD) has emerged as the major pediatric chronic liver disease, and it is estimated to affect more than one third of obese children in the U.S. Cardiovascular complications are a leading cause of increased mortality in adults with NAFLD and many adolescents with NAFLD already manifest signs of subclinical atherosclerosis including increased carotid intima-media thickness.

Methods

Volume of intrahepatic fat was assessed in 50 Hispanic-American, overweight adolescents, using Magnetic Resonance Spectroscopy. Lipoprotein compositions were measured using Nuclear Magnetic Resonance.

Results

Plasma triglycerides (TG) (p = 0.003), TG/HDL ratio (p = 0.006), TG/apoB ratio (p = 0.011), large VLDL concentration (p = 0.019), VLDL particle size (p = 0.012), as well as small dense LDL concentration (p = 0.026) progressively increased across higher levels of hepatic fat severity, while large HDL concentration progressively declined (p = 0.043). This pattern of associations remained even after controlling for gender, BMI, visceral fat, and insulin resistance.

Conclusions

Our findings suggest that increased hepatic fat is strongly associated with peripheral dyslipidemia and the amount of fat in the liver may influence cardiovascular risk. Further studies are needed to longitudinally monitor dyslipidemia in children with NAFLD and to examine whether the reduction of hepatic fat would attenuate their long-term CVD risk.

Influence of lifestyle-related diseases and age on the development and progression of non-alcoholic fatty liver disease

AIM

Although non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, the clinical association between non-alcoholic steatohepatitis (NASH) and lifestyle-related diseases such as obesity, type 2 diabetes mellitus (DM), hypertension (HT) and dyslipidemia (DL) has not been clarified. We studied the influence of lifestyle-related diseases and age on the development and progression of NAFLD.

METHODS

We enrolled 550 patients with biopsy-proven NAFLD (284 men, 266 women; average age, 52 and 62 years, respectively). The effect of lifestyle-related diseases and age (≤49 vs ≥50 years) on the frequency of NASH and advanced fibrosis (≥stage 3) was studied.

RESULTS

Prevalence of obesity, DM, HT and DL in male and female NASH patients was 75%/67%, 53%/54%, 66%/77% and 85/79%, respectively. DM patients had a higher frequency of NASH in the older male NAFLD group and a higher frequency of advanced fibrosis in the older female NASH group. With the increasing number of complicating lifestyle-related diseases, the rate of NASH increased in male NAFLD patients. In both sexes, aging resulted in the development of NASH and progression of liver fibrosis. Multivariate logistic regression analysis revealed that age and DM were significantly associated with the development of NASH in male NAFLD patients and progression of fibrosis in female NASH patients.

CONCLUSION

Age is strongly associated with the development and progression of NASH. Type 2 DM may play the most crucial role among lifestyle-related diseases in the development and progression of NASH.

Management and diagnosis of fatty liver disease

Nonalcoholic fatty liver disease is a common cause of chronic liver disease and has been an increasingly studied topic of research as the obesity epidemic has been growing. There is a significant morbidity and mortality with uncontrolled steatohepatitis, which can progress to fibrosis, cirrhosis and hepatocellular carcinoma. The prevalence of this disease has been estimated to be roughly one-third of the western population, thought to be largely due to diet and sedentary lifestyle. Several treatments have been studied including vitamin E, insulin-sensitizing agents and ursodeoxycholic acid; however, the only treatment shown to improve the histologic changes of nonalcoholic fatty liver disease is weight loss. Given the proven benefit of weight loss, there may be reason to screen at-risk populations; however, limited availability of other disease-modifying treatments may limit the cost-benefit ratios. A better understanding of the diagnosis and management of this condition is required to alter the course of this modifiable disease.

The association of liver enzymes with biomarkers of subclinical myocardial damage and structural heart disease

BACKGROUND & AIMS

Patients with non-alcoholic fatty liver disease (NAFLD) are thought to be at increased risk of cardiovascular morbidity and mortality. However, the relationships between NAFLD and subclinical myocardial injury or structural heart disease are unknown.

METHODS

We conducted a cross-sectional analysis of 8668 participants from the Atherosclerosis Risk in Communities (ARIC) Study, who showed no clinical evidence of cardiovascular disease. We used levels of liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST] and gamma-glutamyl transpeptidase [GGT]), in the context of no history of elevated alcohol consumption as non-invasive surrogates of NAFLD. We used highly sensitive cardiac troponin T (hs-cTnT) and N-terminal pro-Brain natriuretic peptide (NT-proBNP) as biomarkers of myocardial damage and function.

RESULTS

In this population-based study (mean age 63 years, 60% women, 78% white), higher levels of ALT, AST, and GGT, even within the normal range, were significantly and independently associated with detectable (hs-cTnT >3 ng/L) and elevated (hs-cTnT ⩾14 ng/L) concentrations of hs-cTnT. The adjusted odds ratios (95% confidence interval) for elevated liver enzymes (vs. normal levels) with elevated hs-cTnT were: 1.65 (1.28-2.14) for ALT, 1.90 (1.36-2.68) for AST, and 1.55 (1.13-2.12) for GGT. Furthermore, there was evidence for inverse associations of ALT and AST with NT-proBNP.

CONCLUSIONS

Our results suggest that elevated liver enzyme levels in the absence of elevated alcohol consumption may be associated with subclinical myocardial injury. The inverse association between NT-proBNP and both ALT and AST supports the recently described metabolic role of natriuretic peptides.

Current efforts and trends in the treatment of NASH

Of all the aspects of non-alcoholic fatty liver disease (NAFLD), the slowest advances have occurred in the therapeutic field. Thirty-five years after its formal description and after 15 years of intense scrutiny from researchers worldwide, there is still no approved drug for the treatment of non-alcoholic steatohepatits (NASH). In the meantime, progress in the understanding of pathophysiology, diagnosis - both invasive and non-invasive, epidemiology and even natural history have been substantial or, at times, spectacular. In contrast, hepatitis C virus (HCV) therapy underwent constant improvement and even before the great acceleration of the past few years, patients were already being offered approved therapies that were increasingly more efficient. What then explains such a slow pace of therapeutic advances in NASH, and will this change in the near future? Here we will review commonly-held myths that have diverted attention from therapy of NASH, obstacles that have slowed down industrial development of drugs for this indication, and recent achievements that will create better conditions for drug development programs. We will also briefly review current knowledge of non-pharmacological and pharmacological management in this early era of NASH therapies.

Challenges and opportunities in drug and biomarker development for nonalcoholic steatohepatitis: findings and recommendations from an American Association for the Study of Liver Diseases-U.S. Food and Drug Administration Joint Workshop

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease (CLD) in North America. It is a growing contributor to the burden of CDL requiring liver transplantation. Cirrhosis is also associated with an increased risk of hepatocellular cancer, which may occur even in the absence of cirrhosis in subjects with nonalcoholic steatohepatitis (NASH), the histological form of NAFLD associated with increased liver-related mortality. The diagnosis of NASH currently requires a liver biopsy. There are also no U.S. Food and Drug Administration (FDA)-approved therapies for NASH. Therefore, there is a need to develop better diagnostic and therapeutic strategies for patients with NASH, targeting both those with early-stage disease as well as those with advanced liver fibrosis. There are unique challenges in the design of studies for these target populations. The long relatively asymptomatic time interval in the progression of NAFLD and NASH to cirrhosis and ultimately liver failure, along with gaps in knowledge regarding disease modifiers, combine to present significant challenges in trial design. Therefore, there is an urgent need to develop methods to identify the populations at particular risk of disease progression and validate endpoints that reflect meaningful changes in health status in this population. This article summarizes the discussion at a joint workshop held September 5 and 6, 2013 in Silver Spring, Maryland, sponsored by the FDA and the American Association for the Study of Liver Diseases to develop guidance on diagnostic and therapeutic modalities for NASH.

Outcomes in liver transplantation: does sex matter?

A growing literature has highlighted important differences in transplant-related outcomes between men and women. In the United States there are fewer women than men on the liver transplant waitlist and women are two times less likely to receive a deceased or living-related liver transplant. Sex-based differences exist not only in waitlist but also in post-transplant outcomes, particularly in some specific liver diseases, such as hepatitis C. In the era of individualized medicine, recognition of these differences in the approach to pre and post-liver transplant care may impact short and long-term outcomes.

Ezetimibe for the treatment of nonalcoholic steatohepatitis: assessment by novel magnetic resonance imaging and magnetic resonance elastography in a randomized trial (MOZART trial)

Ezetimibe inhibits intestinal cholesterol absorption and lowers low-density lipoprotein cholesterol. Uncontrolled studies have suggested that it reduces liver fat as estimated by ultrasound in nonalcoholic steatohepatitis (NASH). Therefore, we aimed to examine the efficacy of ezetimibe versus placebo in reducing liver fat by the magnetic resonance imaging-derived proton density-fat fraction (MRI-PDFF) and liver histology in patients with biopsy-proven NASH. In this randomized, double-blind, placebo-controlled trial, 50 patients with biopsy-proven NASH were randomized to either ezetimibe 10 mg orally daily or placebo for 24 weeks. The primary outcome was a change in liver fat as measured by MRI-PDFF in colocalized regions of interest within each of the nine liver segments. Novel assessment by two-dimensional and three-dimensional magnetic resonance elastography was also performed. Ezetimibe was not significantly better than placebo at reducing liver fat as measured by MRI-PDFF (mean difference between the ezetimibe and placebo arms -1.3%, P = 0.4). Compared to baseline, however, end-of-treatment MRI-PDFF was significantly lower in the ezetimibe arm (15%-11.6%, P < 0.016) but not in the placebo arm (18.5%-16.4%, P = 0.15). There were no significant differences in histologic response rates, serum alanine aminotransferase and aspartate aminotransferase levels, or longitudinal changes in two-dimensional and three-dimensional magnetic resonance elastography-derived liver stiffness between the ezetimibe and placebo arms. Compared to histologic nonresponders (25/35), histologic responders (10/35) had a significantly greater reduction in MRI-PDFF (-4.35 ± 4.9% versus -0.30 ± 4.1%, P < 0.019).

CONCLUSIONS

Ezetimibe did not significantly reduce liver fat in NASH. This trial demonstrates the application of colocalization of MRI-PDFF-derived fat maps and magnetic resonance elastography-derived stiffness maps of the liver before and after treatment to noninvasively assess treatment response in NASH.

Readiness for behaviour change in non-alcoholic fatty liver disease: implications for multidisciplinary care models

BACKGROUND & AIMS

Weight management is a cornerstone of treatment for overweight/obese persons with non-alcoholic fatty liver disease (NAFLD). This exploratory study sought to: (i) evaluate readiness to change weight-related behaviours; (ii) assess psychosocial characteristics that may interfere with weight loss; and (iii) evaluate how baseline psychosocial features associate with 6-month change in weight in persons with NAFLD receiving standard medical care. The purpose of this investigation was to develop hypotheses regarding relationships between psychosocial factors and weight for use in future fully powered studies and clinical interventions

METHODS

Fifty-eight overweight/obese participants with NAFLD completed baseline measures of personality, psychiatric symptoms and readiness for behaviour change and were followed up for 6 months in standard care.

RESULTS

One-third of participants (31.0%) were not interested in making weight-related behaviour changes; 58.6% were considering making a change, and 10.4% of individuals were actively working on or preparing to change. Six-month change in weight was non-significant and was not associated with baseline readiness for change. Depression, low conscientiousness and high neuroticism were associated with higher weight at 6-month follow-up with small to large effect sizes.

CONCLUSIONS

Although participants received nutritional education and guidance, very few individuals presented in the active stage of change. Although readiness for change did not predict subsequent change in weight, personality factors and psychiatric symptoms were associated with weight outcomes. Integrated multidisciplinary approaches that address psychiatric needs and provide behavioural support for weight loss may help patients with NAFLD implement sustained lifestyle changes.