The natural history of nonalcoholic fatty liver disease: a clinical histopathological study

Preoperative 4-week supplementation with omega-3 polyunsaturated fatty acids reduces liver volume and facilitates bariatric surgery in morbidly obese patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a very common condition among obese patients that may lead to the enlargement of the liver, that in turn impairs the access to the gastro-esophageal junction during laparoscopic bariatric surgery. Omega-3 polyunsaturated fatty acids (Ω-3 PUFAs) supplementation has been shown to reduce nutritional hepatic steatosis. The aim of this study was to assess the effects of a 4-week course of oral Ω-3 PUFAs supplementation on the volume of the liver.

METHODS

20 morbidly obese patients were administered oral Ω-3 PUFAs (1,500 mg daily) for 4 weeks before undergoing the laparoscopic Roux-en-Y gastric bypass (LRYGBP) without any dietary restriction. The volume of the left hepatic lobe was estimated by liver ultrasonography at baseline and at the end of treatment. The degree of difficulty to access the gastro-esophageal junction was appreciated subjectively by the operating surgeon.

RESULTS

All patients completed the study and no side effect was reported. The mean volume of the left hepatic lobe decreased by 20% from 598 ± 97 to 484 ± 118 cm(3) after the treatment (p = 0.002). The access to the gastro-esophageal junction was reported as simple, with easy retraction of the left hepatic lobe by the operating surgeon in all cases.

CONCLUSIONS

This study demonstrates that a 4-week course of oral Ω-3 PUFAs supplementation results in a significant reduction in liver size that facilitates the LRYGBP.

Nonalcoholic fatty liver disease is associated with coronary artery disease in Koreans

AIM: To investigate whether nonalcoholic fatty liver disease (NAFLD) affects coronary artery disease (CAD) and identify candidate mediators.

METHODS: Patients who underwent coronary angiography were consecutively recruited. The patients were classified into four groups by coronary artery stenosis: A, insignificant; B, one-vessel disease; C, two-vessel disease; and D, three-vessel disease. Abdominal ultrasonography was performed to determine the presence of a fatty liver and categorize by grade: 0, no evidence; 1, mild; 2, moderate; and 3, severe. We measured not only known CAD risk factors, but also serum insulin, HOMA-index, adiponectin, interleukin-6, tumor necrosis factor-α and high-sensitivity C-reactive protein levels.

RESULTS: Of the 134 patients who met the inclusion criteria, 82 (61.2%) had ultrasonographically diagnosed NAFLD. Among the 46 patients with CAD, 37 (80.4%) had evidence of a fatty liver. The two groups (A vs B-D) were significantly different in terms of age, total cholesterol, triglycerides, low-density lipoprotein levels and fatty liver. Coronary artery stenosis was strongly associated with fatty liver in a grade-dependent manner (P = 0.025). In binary logistic regression, NAFLD was a significant independent predictor of CAD (P = 0.03, OR = 1.685; 95%CI: 1.051-2.702). Among the candidate mediators, the serum adiponectin level showed a trend toward lowering based on CAD progression (P = 0.071).

CONCLUSION: NAFLD is an independent risk factor for CAD in a grade-dependent manner. Moreover, adiponectin might be related to the pathogenesis of NAFLD.

From NAFLD in clinical practice to answers from guidelines

This review of the literature consists of three sections. First, papers concerning non-alcoholic fatty liver disease (NAFLD) awareness among the general population, general practitioners, and liver and non-liver specialists were retrieved and analyzed to highlight the perception of disease, verify knowledge of current recommendations, and identify the main difficulties experienced in clinical practice. Next, position papers and clinical practice guidelines issued by International and National Hepatological Scientific Societies were identified and critically assessed in order to pinpoint the areas of convergence/difference. Finally, practical suggestions on NAFLD diagnosis and management in daily practice are provided and the open questions highlighted.

Steatohepatitic hepatocellular carcinoma, a morphologic indicator of associated metabolic risk factors: a study from India

CONTEXT

The common risk factors for hepatocellular carcinoma (HCC) include persistent viral infection with either hepatitis B or C virus, alcohol abuse, hemochromatosis, and metabolic syndrome. Steatohepatitic (SH) HCC has been recently recognized as a special morphologic variant of HCC associated with metabolic risk factors.

OBJECTIVE

To assess the SH pattern in HCC cases of various etiologies in Indian patients and to further correlate this morphology with the presence of metabolic risk factors.

DESIGN

A total of 101 cases of HCC with various etiologies in explanted livers from adults were included in the study. Morphologic examination was performed to identify SH lesions within the tumor and in the nontumorous liver parenchyma. Correlation of nontumor and tumor SH morphology with clinically identifiable metabolic risk factors and with non-SH type of HCC was performed.

RESULTS

The SH variant of HCC was identified in 19 livers (18.8%). Most SH-HCC cases were associated with metabolic risk factors such as obesity, diabetes, hypertension, and hyperlipidemias. Comparison of SH-HCC with non-SH-HCC was statistically significant in terms of presence of metabolic risk factors.

CONCLUSIONS

Steatohepatitic morphology in HCC is frequent in nonalcoholic fatty liver disease-associated cirrhosis (P = .009) and is significantly associated with metabolic risk factors (P = .03). By recognizing SH pattern, one may predict associated metabolic diseases and determine the prognosis both in pretransplant and posttransplant patients.

Non-B, non-C hepatocellular carcinoma (Review)

Although most hepatocellular carcinoma (HCC) is related to viral infection, there is a substantial population of HCC patients (5-20%) who are negative for both markers of hepatitis B virus and hepatitis C virus infection [non-B, non-C (NBNC) hepatitis] in Japan and the incidence of NBNC-HCC has recently tended to increase. The most common cause of liver disease in developed countries is non‑alcoholic fatty liver disease (NAFLD), which includes non‑alcoholic steatohepatitis (NASH) and its related complications. Increased body mass index and diabetes mellitus are associated with developing NAFLD and NASH, which is a severe form of NAFLD. Furthermore, increasing clinical evidence supports the fact that NAFLD and NASH can progress to liver cirrhosis and even HCC. A detailed understanding of the epidemiology, etiology, molecular mechanism, clinical features and prognosis of NBNC-HCC could improve our screening and therapy of this disease. In this review, we primarily focus on clinical aspects of NBNC-HCC and refer to our current knowledge of this cancer.

MR fat fraction mapping: a simple biomarker for liver steatosis quantification in nonalcoholic fatty liver disease patients

RATIONALE AND OBJECTIVES

To assess the performance, postprocessing time, and intra- and interobserver agreement of a simple magnetic resonance-based mapping technique to quantify liver fat.

MATERIALS AND METHODS

This prospective, single-center study included 26 patients who were overweight with type 2 diabetes and at risk for nonalcoholic fatty liver disease. Mapping of the liver was based on a triple echo gradient-echo sequence, and (1)H magnetic resonance spectroscopy was used as the reference standard. The nonparametric Spearman correlation coefficient and the Wilcoxon test were used for comparisons between mapping and spectroscopy. The mapping was assessed for its predictive performance using the area under the curve of a receiver operating characteristic curve. Intraclass correlation coefficients were used to calculate intra- and interobserver's agreement for mapping measurements.

RESULTS

Patients had a mean fat percentage of 11.7% (range, 2-35.4%). A strong correlation was seen between mapping and spectroscopy (r = 0.89, P < .0001). A cutoff of 6.9% for fat fraction mapping was found to diagnose steatosis with 93% sensitivity and 100% specificity with an area under the curve of 0.99. Mapping of the liver had shorter acquisition and post-processing times than spectroscopy (5 min vs. 38 min; P < .0001). Mapping measurements had an intra- and interobserver agreement of 0.98 and 0.99, respectively.

CONCLUSIONS

The magnetic resonance-based liver mapping can accurately quantify liver fat with a cutoff value of 6.9% and excellent intra- and interobserver agreement. This mapping technique, with its simple methodology and short postprocessing time, has the potential to be included in routine abdominal protocols.

Nonalcoholic fatty liver disease: current issues and novel treatment approaches

Nonalcoholic fatty liver disease (NAFLD) is considered the most common liver disorder in the Western world. It is commonly associated with insulin resistance, obesity, dyslipidaemia, type 2 diabetes mellitus (T2DM) and cardiovascular disease. Nonalcoholic steatohepatitis (NASH) is characterized by steatosis with necroinflammation and eventual fibrosis, which can lead to end-stage liver disease and hepatocellular carcinoma. Its pathogenesis is complex, and involves a state of 'lipotoxicity' in which insulin resistance, with increased free fatty acid release from adipose tissue to the liver, play a key role in the onset of a 'lipotoxic liver disease' and its progression to NASH. The diagnosis of NASH is challenging, as most affected patients are symptom free and the role of routine screening is not clearly established. A complete medical history is important to rule out other causes of fatty liver disease (alcohol abuse, medications, other). Plasma aminotransferase levels and liver ultrasound are helpful in the diagnosis of NAFLD/NASH, but a liver biopsy is often required for a definitive diagnosis. However, there is an active search for plasma biomarkers and imaging techniques that may non-invasively aid in the diagnosis. The treatment of NASH requires a multifaceted approach. The goal is to reverse obesity-associated lipotoxicity and insulin resistance via lifestyle intervention. Although there is no pharmacological agent approved for the treatment of NAFLD, vitamin E (in patients without T2DM) and the thiazolidinedione pioglitazone (in patients with and without T2DM) have shown the most consistent results in randomized controlled trials. This review concentrates on our current understanding of the disease, with a focus on the existing therapeutic approaches and potential future pharmacological developments for NAFLD and NASH.

Prevalence of nonalcoholic fatty liver disease in the United States: the Third National Health and Nutrition Examination Survey, 1988-1994

Previous estimates of the prevalence of nonalcoholic fatty liver disease (NAFLD) in the US population relied on measures of liver enzymes, potentially underestimating the burden of this disease. We used ultrasonography data from 12,454 adults who participated in the Third National Health and Nutrition Examination Survey, conducted in the United States from 1988 to 1994. We defined NAFLD as the presence of hepatic steatosis on ultrasonography in the absence of elevated alcohol consumption. In the US population, the rates of prevalence of hepatic steatosis and NAFLD were 21.4% and 19.0%, respectively, corresponding to estimates of 32.5 (95% confidence interval: 29.9, 35.0) million adults with hepatic steatosis and 28.8 (95% confidence interval: 26.6, 31.2) million adults with NAFLD nationwide. After adjustment for age, income, education, body mass index (weight (kg)/height (m)²), and diabetes status, NAFLD was more common in Mexican Americans (24.1%) compared with non-Hispanic whites (17.8%) and non-Hispanic blacks (13.5%) (P = 0.001) and in men (20.2%) compared with women (15.8%) (P < 0.001). Hepatic steatosis and NAFLD were also independently associated with diabetes, with insulin resistance among people without diabetes, with dyslipidemia, and with obesity. Our results extend previous national estimates of the prevalence of NAFLD in the US population and highlight the burden of this disease. Men, Mexican Americans, and people with diabetes and obesity are the most affected groups.

Soluble CD14 levels reflect liver inflammation in patients with nonalcoholic steatohepatitis

BACKGROUND AIMS

Liver inflammation is a risk factor for the progression of nonalcoholic fatty liver disease (NAFLD). However, the diagnosis of liver inflammation is very difficult and invasive liver biopsy is still the only method to reliably detect liver inflammation. We previously reported that overexpression of CD14 in Kupffer cells may trigger the progression to nonalcoholic steatohepatitis (NASH) via liver inflammation following hyper-reactivity to low-dose lipopolysaccharide. Therefore, the aim of this study was to investigate the relationship between soluble type of CD14 (sCD14) and histological features in patients with NAFLD.

METHODS

Our cohort consisted of 113 patients with liver biopsy-confirmed NAFLD and 21 age-matched healthy controls. Serum sCD14 levels were measured by an enzyme-linked immunosorbent assay.

RESULTS

Serum sCD14 levels were significantly associated with diagnosis of NASH and the area under the receiver operator characteristic curve (AUROC) to distinguish between not NASH and NASH was 0.802. Moreover, serum sCD14 levels were significantly associated with the disease activity based on NAFLD activity score and hepatic CD14 mRNA expression, which is correlated with membrane CD14 (mCD14) expression, in patients with NAFLD. In multiple regression analysis, the serum sCD14 levels were independently associated with liver inflammation. The AUROC to distinguish between mild and severe liver inflammation in patients with NAFLD was 0.752.

CONCLUSIONS

We found that serum sCD14 levels increased significantly with increasing liver inflammation grade in patients with NAFLD, reflecting increased hepatic CD14 expression. Serum sCD14 is a promising tool to predict the worsening of liver inflammation, and may offer a potential biomarker for evaluation of therapeutic effects in NAFLD.

Progression of NAFLD to diabetes mellitus, cardiovascular disease or cirrhosis

NAFLD is a spectrum of progressive liver disease that encompasses simple steatosis, NASH, fibrosis and, ultimately, cirrhosis. NAFLD is recognized as the hepatic component of the metabolic syndrome, as these conditions have insulin resistance as a common pathophysiological mechanism. Therefore, NAFLD is strongly associated with type 2 diabetes mellitus and abdominal obesity. As lifestyles have become increasingly sedentary and dietary patterns have changed, the worldwide prevalence of NAFLD has increased dramatically and is projected to be the principal aetiology for liver transplantation within the next decade. Importantly, a growing body of clinical and epidemiological evidence suggests that NAFLD is associated not only with liver-related morbidity and mortality, but also with an increased risk of developing both cardiovascular disease and type 2 diabetes mellitus. This article reviews the evidence that suggests NAFLD is a multisystem disease and the factors that might determine interindividual variation in the development and progression of its major hepatic and extrahepatic manifestations (principally type 2 diabetes mellitus and cardiovascular disease).

Heterogeneity of fibrosis patterns in non-alcoholic fatty liver disease supports the presence of multiple fibrogenic pathways

BACKGROUND

Adult non-alcoholic fatty liver disease (NAFLD) involves lobular necroinflammatory activity and fibrosis is typically centrilobular, whereas paediatric NAFLD has predominantly portal fibrosis. The reasons for these differences are unclear. We aimed to determine (a) how centrilobular and portal fibrosis in children relate to histological parameters; and (b) whether atypical fibrosis patterns exist in adults that are unexplained by current fibrogenesis models.

METHODS

Histological features of paediatric (n = 38) and adult (n = 56) NAFLD were assessed using conventional scoring systems. Keratin-7 immunostaining was used to assess hepatic progenitor cell numbers and the ductular reaction. Centrilobular and portal components of fibrosis were independently scored and fibrosis patterns were classified according to accepted types. Post-treatment (rosiglitazone/gastric banding) biopsies were also examined in adults.

RESULTS

Twenty-six children (68.4%) had portal-predominant fibrosis, although the typical "adult" pattern was seen in 11 (28.9%). Portal fibrosis was associated with a ductular reaction (P = 0.021) and hepatic progenitor cell expansion (P < 0.001), whereas centrilobular fibrosis was associated with lobular inflammation (P = 0.026) and ballooning (P = 0.001). Before intervention, six adults (10.7%) had atypical fibrosis including 3 (5.4%) with a previously unrecognized pattern of very fine, non-zonal sinusoidal fibrosis. Despite improvements in steatosis and inflammation, more patients developed this unusual pattern after intervention with most having had surgery (9 of 10 adults; P < 0.001).

CONCLUSION

Differing associations with portal and centrilobular fibrosis in children and atypical fibrosis patterns in adults suggest that multiple fibrogenic pathways exist in NAFLD. This has implications for therapy and understanding pathogenesis.

Multidisciplinary management of patients with cirrhosis: a need for care coordination

Cirrhosis is a common chronic condition with high rates of morbidity and mortality. Optimal medical management involves a multidisciplinary approach, but coordination between medical specialties needs to be improved. This clinical perspective discusses care coordination interventions that have been successful in other disease states and how they could be applied to the management of cirrhosis.

NAFLD fibrosis score: a prognostic predictor for mortality and liver complications among NAFLD patients

AIM

To study whether the severity of liver fibrosis estimated by the nonalcoholic fatty liver disease (NAFLD) fibrosis score can predict all-cause mortality, cardiac complications, and/or liver complications of patients with NAFLD over long-term follow-up.

METHODS

A cohort of well-characterized patients with NAFLD diagnosed during the period of 1980-2000 was identified through the Rochester Epidemiology Project. The NAFLD fibrosis score (NFS) was used to separate NAFLD patients with and without advanced liver fibrosis. We used the NFS score to classify the probability of fibrosis as < -1.5 for low probability, > -1.5 to < 0.67 for intermediate probability, and > 0.67 for high probability. Primary endpoints included all-cause death and cardiovascular- and/or liver-related mortality. From the 479 patients with NAFLD assessed, 302 patients (63%) greater than 18 years old were included. All patients were followed, and medical charts were reviewed until August 31, 2009 or the date when the first primary endpoint occurred. By using a standardized case record form, we recorded a detailed history and physical examination and the use of statins and metformin during the follow-up period.

RESULTS

A total of 302/479 (63%) NAFLD patients (mean age: 47 ± 13 year) were included with a follow-up period of 12.0 ± 3.9 year. A low probability of advanced fibrosis (NFS < -1.5 at baseline) was found in 181 patients (60%), while an intermediate or high probability of advanced fibrosis (NSF > -1.5) was found in 121 patients (40%). At the end of the follow-up period, 55 patients (18%) developed primary endpoints. A total of 39 patients (13%) died during the follow-up. The leading causes of death were non-hepatic malignancy (n = 13/39; 33.3%), coronary heart disease (CHD) (n = 8/39; 20.5%), and liver-related mortality (n = 5/39; 12.8%). Thirty patients had new-onset CHD, whereas 8 of 30 patients (27%) died from CHD-related causes during the follow-up. In a multivariate analysis, a higher NFS at baseline and the presence of new-onset CHD were significantly predictive of death (OR = 2.6 and 9.2, respectively; P < 0.0001). Our study showed a significant, graded relationship between the NFS, as classified into 3 subgroups (low, intermediate and high probability of liver fibrosis), and the occurrence of primary endpoints. The use of metformin or simvastatin for at least 3 mo during the follow-up was associated with fewer deaths in patients with NAFLD (OR = 0.2 and 0.03, respectively; P < 0.05). Additionally, the rate of annual NFS change in patients with an intermediate or high probability of advanced liver fibrosis was significantly lower than those patients with a low probability of advanced liver fibrosis (0.06 vs 0.09, P = 0.004). The annual NFS change in patients who died was significantly higher than those in patients who survived (0.14 vs 0.07, P = 0.03). At the end of the follow-up, we classified the patients into 3 subgroups according to the progression pattern of liver fibrosis by comparing the NFS at baseline to the NFS at the end of the follow-up period. Most patients were in the stable-fibrosis (60%) and progressive-fibrosis (37%) groups, whereas only 3% were in the regressive fibrosis.

CONCLUSION

A higher NAFLD fibrosis score at baseline and a new onset of CHD were significantly predictive of death in patients with NAFLD.

Effect of Telmisartan or Losartan for Treatment of Nonalcoholic Fatty Liver Disease: Fatty Liver Protection Trial by Telmisartan or Losartan Study (FANTASY)

AIM

This study compared the effects of telmisartan and losartan on nonalcoholic fatty liver disease (NAFLD) and biochemical markers of insulin resistance in hypertensive NAFLD patients with type 2 diabetes mellitus.

METHODS

This was a randomized, open-label, parallel-group comparison of therapy with telmisartan or losartan. Nineteen hypertensive NAFLD patients with type 2 diabetes were randomly assigned to receive telmisartan at a dose of 40 mg once a day (n = 12) [DOSAGE ERROR CORRECTED] or losartan at a dose of 50 mg once a day (n = 7) for 12 months.

RESULTS

The telmisartan group showed a significant decline in serum free fatty acid (FFA) level (from 0.87 ± 0.26 to 0.59 ± 0.22 mEq/L (mean ± SD), P = 0.005) and a significant increase in L/S ratio (P = 0.049) evaluated by CT scan, while these parameters were not changed in the losartan group.

CONCLUSION

Although there was no significant difference in improvement in liver enzymes with telmisartan and losartan treatment in hypertensive NAFLD patients with type 2 diabetes after 12 months, it is suggested that telmisartan may exert beneficial effects by improving fatty liver.

Risk factors for nonalcoholic steatohepatitis in cryptogenic cirrhosis

CONTEXT

In about 10% of patients with chronic liver disease, it is not possible to identify an etiologic factor. These cases are called cryptogenic cirrhosis. Currently, nonalcoholic steatohepatitis (NASH) is being considered as a possible etiologic factor for a significant segment of patients that presents with cryptogenic cirrhosis.

OBJECTIVE

To estimate the prevalence of risk factors for NASH in patients with cryptogenic cirrhosis, in order to verify if there is a causal relationship between them.

METHOD

Cross-sectional study, with evaluation of the demographic and laboratorial data of patients with cryptogenic cirrhosis. They were compared with data obtained from a group with NASH and a group with alcoholic and/or hepatitis C (HCV) cirrhosis.

RESULTS

Forty seven patients with cryptogenic cirrhosis were evaluated, 47 with NASH and 196 with HCV and/or alcoholic cirrhosis. The mean age of patients with cryptogenic cirrhosis was 52 years, while in those with NASH it was 46.4 years (P = 0,041). The group with cryptogenic cirrhosis had 23 female and 24 male patients. Of the patients who presented with NASH, 68.1% were female. Of the patients who presented with alcoholic/HCV cirrhosis, 64.8% were male. There were no statistically significant differences between the groups. In cryptogenic cirrhosis patients, the following prevalences could be observed: impaired fasting glycemia - 68.2%; obesity - 27.5%; total hypercholesterolemia - 27.9%; low HDL levels - 58.1% (women - 81%; men - 36.4%); hypertriglyceridemia - 16.3%. The results seen in cryptogenic cirrhosis patients showed statistical similarity with the results of the NASH group regarding fasting glycemia (62.8%) and male HDL levels (53.8%). The comparison with the alcoholic/HCV cirrhosis group showed statistical differences regarding fasting glycemia (45.2%), hypercholesterolemia (13.3%) and female HDL levels (50.8%).

CONCLUSIONS

It is not possible to establish a causal relationship between cryptogenic cirrhosis and NASH. Only data related to fasting glycemia and HDL levels in male patients showed statistical similarities between both groups of patients.

Review article: is non-alcoholic fatty liver disease a spectrum, or are steatosis and non-alcoholic steatohepatitis distinct conditions?

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is currently conceptualised as a clinical spectrum that results from a ‘multiple-hit’ process which begins with simple steatosis and subsequently renders the hepatocytes susceptible to a variety of insults. Ultimately, more serious liver injuries like non-alcoholic steatohepatitis (NASH) and cirrhosis may develop. Although the metabolic syndrome is considered the crucial player in the pathogenesis of NAFLD, recent studies have highlighted novel pathophysiological mechanisms in this clinical entity.

AIM

To discuss the pathophysiology of NAFLD based on the hypothesis that simple steatosis and NASH are discrete entities rather than two points on a spectrum.

METHODS

A literature search was conducted in August 2012 on PubMed, Ovid Embase, Ovid Medline and Scopus using the following search terms: steatosis, non-alcoholic steatohepatitis, pathophysiology, fatty liver, natural history and genetics.

RESULTS

Simple steatosis and NASH appear as two distinct pathophysiological entities and progression from pure fatty liver to NASH appears to be so rare as to warrant publication. The possible pathogenetic pathways specifically related to NASH are highlighted.

CONCLUSIONS

Although simple steatosis and non-alcoholic steatohepatitis are currently viewed as two histological subtypes of the unique spectrum of non-alcoholic fatty liver disease, the two conditions are likely distinct not only from a histological but also from a pathophysiological standpoint. Efforts to distinguish simple steatosis from non-alcoholic steatohepatitis using non-invasive modalities should be informed by the current pathophysiology of these two clinical entities.

Nonalcoholic fatty liver disease in lean individuals in the United States

The presence of hepatic steatosis in individuals without a known cause of chronic liver disease, including excessive alcohol consumption, is the hallmark of nonalcoholic fatty liver disease (NAFLD). Although NAFLD is usually associated with obesity, nonobese patients can also present with NAFLD ("lean NAFLD"). Our objective was to determine factors independently associated with lean NAFLD in the United States population. For this purpose, we used data from National Health and Nutrition Examination Survey III (NHANES III) conducted between 1988 and 1994 with available hepatic ultrasound, clinico-demographic, and laboratory data. NAFLD was defined as the presence of moderate-severe hepatic steatosis (by ultrasound), the absence of excessive alcohol use (>20 g/d in men and 10 g/d in women), hepatitis B surface antigen(-), and hepatitis C antibody(-). Nonalcoholic steatohepatitis (NASH) was defined as having moderate-severe steatosis and elevated aminotransferases in the presence of type 2 diabetes or insulin resistance (IR). Logistic regression was used to identify independent predictors of lean NAFLD. As a result, of the 11,613 participants included in the study, 2185 (18.77% ± 0.76%) had NAFLD; of these, 307 (11.78% ± 1.03%) had NASH. Multivariate analysis showed that lean NAFLD was independently associated with younger age, female sex, and a decreased likelihood of having IR and hypercholesterolemia (p values < 0.05). Additionally, multivariate analysis showed that NASH was independently associated with being Hispanic, having a younger age, and having components of metabolic syndrome such as hypertension (p values < 0.05). Therefore, we conclude that lean individuals with NAFLD have a different clinical profile than overweight-obese individuals with NAFLD. Furthermore, patients with NASH are commonly Hispanic and have components of metabolic syndrome.

Pathophysiological analysis of nonalcoholic fatty liver disease by evaluation of fatty liver changes and blood flow using xenon computed tomography: can early-stage nonalcoholic steatohepatitis be distinguished from simple steatosis?

INTRODUCTION

Effective noninvasive tests that can distinguish early-stage nonalcoholic steatohepatitis (NASH) from simple steatosis (SS) have long been sought. Our aim was to determine the possibility of noninvasively distinguishing early-stage NASH from SS.

MATERIALS AND METHODS

We used Fick's principle and the Kety-Schmidt equation to determine the hepatic tissue blood flow (TBF) in 65 NASH patients who underwent xenon computed tomography (Xe-CT). We calculated the lambda value (LV), i.e., Xe gas solubility coefficient, in liver and blood. We assessed the histological severity of fatty changes and fibrosis on the basis of Brunt's classification. Liver biopsy revealed SS in 9 patients and NASH in 56 patients. NASH stages 1 and 2 were classified as early-stage NASH (Ea-NASH; 38 patients) and stages 3 and 4 as advanced-stage NASH (Ad-NASH; 18 patients). We evaluated the differences in LV and TBF among the 3 groups.

RESULTS

LV was significantly lower in the Ad-NASH group than in the SS and Ea-NASH groups. Portal venous TBF (PVTBF) was significantly lower in the Ea-NASH group than in the SS group, and PVTBF was lower in the Ad-NASH group than in the Ea-NASH group. Total hepatic TBF (THTBF) was significantly different between the SS and Ea-NASH groups and between the SS and Ad-NASH groups.

CONCLUSIONS

In conclusion, measurements of TBF and LV are useful for evaluating the pathophysiological progression of NASH. In addition, these measurements can facilitate the differential diagnosis of SS and Ea-NASH, which may not be distinguishable by other means.

Evolution of nonalcoholic fatty liver disease recurrence after liver transplantation

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is the fourth most common indication for liver transplantation. Risk factors for NAFLD can persist and even worsen after liver transplantation. However, the risk and significance of NAFLD recurrence remain unclear. Reported posttransplant NAFLD and NASH recurrence rates vary widely across studies. There is little information detailing the histological evolution of NAFLD recurrence, and the long-term natural history of NAFLD recurrence is unclear. In this review, we summarize the findings of studies on the prevalence of recurrent NAFLD and its risk factors in the posttransplant setting, and we explore reasons for the discrepant reported recurrence rates. On the basis of currently available data, the relatively low rates of advanced fibrosis and NAFLD-associated graft loss and the comparability of the survival rates for these patients and patients undergoing transplantation for other diseases suggest that although NAFLD or NASH can recur, the clinical significance of disease recurrence for graft or patient survival may be small.

Hepatic steatosis and steatohepatitis in human immunodeficiency virus/hepatitis C virus-coinfected patients

Hepatic steatosis (HS) is frequent in human immunodeficiency virus (HIV)- and hepatitis C virus (HCV)-coinfected patients. Antiretroviral therapy (ART) and metabolic alterations could induce HS. However, a protective effect of ART has been reported in a paired biopsy study. Thus, our aim was to examine the changes and predictors of HS progression among HIV/HCV-coinfected patients with sequential biopsies. We also evaluated the rates of steatohepatitis and factors associated thereof. HIV-infected patients with detectable serum HCV RNA, who underwent two biopsies, separated at least by 1 year, were included in this retrospective study. HS progression was defined as increase in one or more HS grades. The median (interquartile range) time between biopsies was 3.3 (2.0-5.2) years. Among 146 individuals, HS at baseline was observed in 86 (60%) patients and in 113 (77%) in the follow-up biopsy (P < 0.001). Progression of HS was observed in 60 (40%) patients. HS regressed in 11 (8%) patients. Factors associated with HS progression were changes in fasting plasma glucose (FPG) between biopsies (per 10 mg/dL increase; odds ratio [OR] [95% confidence interval; CI] = 1.4 [1.04-1.8]; P = 0.024) and cumulative use of dideoxynucleoside analogs (per year; OR [95% CI] = 1.5 [1.2-1.8]; P = 0.001). Persistent steatohepatitis or progression to steatohepatitis between biopsies was observed in 27 (18%) patients. Persistence of or progression to steatohepatitis was associated with progression ≥ 1 fibrosis stages between biopsies (OR [95% CI] = 2.4 [1.01-5.7]; P = 0.047).

CONCLUSIONS

HS progresses frequently and regression is rarely observed in HIV/HCV-coinfected patients, including in those on ART. Cumulative exposure to dideoxynucleoside analogs and increases in FPG are related with HS progression. Stetatohepatitis is frequently observed in these patients and is linked to fibrosis progression.

Effects of different therapeutic methods and typical recipes of Chinese medicine on activation of c-Jun N-terminal kinase in kupffer cells of rats with fatty liver disease

OBJECTIVE

To observe the effects of different therapeutic methods and the recipes of Chinese medicine (CM) on the activation of c-Jun N-terminal kinase (JNK) in Kupffer cells of rats with fatty liver disease and to explore the mechanisms of these therapeutic methods.

METHODS

By using a random number table, 98 rats were randomly divided into 7 groups: control group, model group, and 5 treatment groups, including soothing Liver (Gan) recipe group, invigorating Spleen (Pi) recipe group, dispelling dampness recipe group, promoting blood recipe group, and complex recipe group. Rats in the control group were fed with normal food and distilled water by gastric perfusion, while rats in the model group were fed with high-fat food and distilled spirits by gastric perfusion. Rats in the 5 treatment groups were fed with high-fat food and corresponding recipes by gastric perfusion. Twelve weeks later, all rats were sacrificed and liver tissues were stained for pathohistological observation. Kupffer cells were isolated from livers of rats to evaluate JNK and phospho-JNK expressions by Western blotting.

RESULTS

The grade of hepatic steatosis was higher in the model group than the control group (P<0.05). Compared with the model group, the grade of fatty degeneration in soothing Liver recipe group and invigorating Spleen recipe group were significantly ameliorated (P<0.05). Expressions of JNK and phospho-JNK in Kupffer cells were significantly higher in the model group than those in the control group (P<0.05, P<0.01). Compared with the model group, expressions of JNK in all treatment groups decreased, especially in invigorating Spleen recipe group and promoting blood recipe group (P<0.05). Compared with the model group, expressions of phospho-JNK in all treatment groups declined significantly (P<0.01), especially in soothing Live recipe group and invigorating Spleen recipe group.

CONCLUSIONS

The high expressions of JNK and phospho-JNK in Kupffer cells might play an important role in the pathogenesis of fatty liver disease in rats. The recipes of CM, especially invigorating Spleen recipe and soothing Liver recipe, might protect liver against injury by reducing the total JNK protein content and inhibiting the activation of JNK protein in Kupffer cells of fatty liver model rats, which showed beneficial effects on fatty liver disease.

Hepatic fat quantification: a prospective comparison of magnetic resonance spectroscopy and analysis methods for chemical-shift gradient echo magnetic resonance imaging with histologic assessment as the reference standard

OBJECTIVE

The aims of this study were to assess the confounding effects of hepatic iron deposition, inflammation, and fibrosis on hepatic steatosis (HS) evaluation by magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) and to assess the accuracies of MRI and MRS for HS evaluation, using histology as the reference standard.

MATERIALS AND METHODS

In this institutional review board-approved prospective study, 56 patients gave informed consents and underwent chemical-shift MRI and MRS of the liver on a 1.5-T magnetic resonance scanner. To estimate MRI fat fraction (FF), 4 analysis methods were used (dual-echo, triple-echo, multiecho, and multi-interference), and MRS FF was calculated with T2 correction. Degrees of HS, iron deposition, inflammation, and fibrosis were analyzed in liver resection (n = 37) and biopsy (n = 19) specimens. The confounding effects of histology on fat quantification were assessed by multiple linear regression analysis. Using the histologic degree of HS as the reference standard, the accuracies of each method in estimating HS and diagnosing an HS of 5% or greater were determined by linear regression and receiver operating characteristic analyses.

RESULTS

Iron deposition significantly confounded estimations of FF by the dual-echo (P < 0.001) and triple-echo (P = 0.033) methods, whereas no histologic feature confounded the multiecho and multi-interference methods or MRS. The MRS (r = 0.95) showed the strongest correlation with histologic degree of HS, followed by the multiecho (r = 0.92), multi-interference (r = 0.91), triple-echo (r = 0.90), and dual-echo (r = 0.85) methods. For diagnosing HS, the areas under the curve tended to be higher for MRS (0.96) and the multiecho (0.95), multi-interference (0.95), and triple-echo (0.95) methods than for the dual-echo method (0.88) (P ≥ 0.13).

CONCLUSION

The multiecho and multi-interference MRI methods and MRS can accurately quantify hepatic fat, with coexisting histologic abnormalities having no confounding effects.

Recurrence of non-alcoholic steatohepatitis and cryptogenic cirrhosis following orthotopic liver transplantation in the context of the metabolic syndrome

BACKGROUND

Non-alcoholic steatohepatitis (NASH) and cryptogenic cirrhosis (CC) are increasing indications for orthotopic liver transplantation (OLT). The aim of this study is to describe our outcomes and delineate predictors of recurrence of NASH and CC after OLT.

METHODS

This is a retrospective study from 1996 to 2008. Donor and recipient demographics, metabolic profile, insulin and steroid intake, immunosuppression regimen, operative factors, outcomes, and pathologies were reviewed. Fisher's exact test, Cox regression models, and Kaplan-Meier plots were used.

RESULTS

A total of 83 patients were included. Recurrence occurred in 20 patients. Thirty-four percent of the patients with metabolic syndrome (MS) had recurrence of NASH or CC compared with 13% of the patients without MS (p = 0.05). Recurrence also occurred in 32% of the patients with hypertension (HTN) vs. 12% in those without HTN (p = 0.05). Thirty-seven percent of those on insulin had recurrence vs. 6% of those not on insulin (p = 0.05). Five-yr survival probability for patients with MS, HTN, and insulin use was 52%, 61%, and 58%, respectively.

CONCLUSIONS

Higher recurrence of NASH and CC was associated with presence of MS, HTN and insulin use. Recurrence should be further evaluated in larger studies, with special emphasis on management of MS and prevention strategies.

Equivalent survival following liver transplantation in patients with non-alcoholic steatohepatitis compared with patients with other liver diseases

BACKGROUND

Orthotopic liver transplantation (LT) in non-alcoholic steatohepatitis (NASH) is increasing in parallel with the obesity epidemic.

METHODS

This study retrospectively reviewed the clinical outcomes of LTs in NASH (n = 129) and non-NASH (n = 775) aetiologies carried out at a single centre between 1999 and 2009.

RESULTS

Rates of 1-, 3- and 5-year overall survival in NASH (90%, 88% and 85%, respectively) were comparable with those in non-NASH (92%, 86% and 80%, respectively) patients. Mortality within 4 months of LT was twice as high in NASH as in non-NASH patients (8.5% vs. 4.2%; P = 0.04). Compared with non-NASH patients, post-LT mortality in NASH patients was more commonly caused by infectious (38% vs. 26%; P < 0.05) or cardiac (19% vs. 7%; P < 0.05) aetiologies. Five-year survival was lower in NASH patients with a high-risk phenotype (age >60 years, body mass index >30 kg/m(2), with hypertension and diabetes) than in NASH patients without these characteristics (72% vs. 87%; P = 0.02). Subgroup analyses revealed that 5-year overall survival in NASH was equivalent to that in Laennec's cirrhosis (85% vs. 80%; P 0.87), but lower than that in cirrhosis of cryptogenic aetiology (85% vs. 96%; P = 0.04).

CONCLUSIONS

Orthotopic LT in NASH was associated with increased early postoperative mortality, but 1-, 3- and 5-year overall survival rates were equivalent to those in non-NASH patients.

Association between diabetes, family history of diabetes, and risk of nonalcoholic steatohepatitis and fibrosis

Previous studies have shown familial aggregation of insulin resistance and nonalcoholic fatty liver disease (NAFLD). Therefore, we aimed to examine whether family history of diabetes mellitus (DM) is associated with nonalcoholic steatohepatitis (NASH) and fibrosis in patients with NAFLD. This was a cross-sectional analysis in participants of the NAFLD Database study and PIVENS trial who had available data on family history of DM. One thousand and sixty-nine patients (63% women), with mean age of 49.6 (± 11.8) years and body mass index (BMI) of 34.2 (± 6.4) kg/m(2) , were included. Thirty percent had DM, and 56% had a family history of DM. Both personal history of DM and family history of DM were significantly associated with NASH, with an odds ratio (OR) of 1.93 (95% confidence interval [CI]: 1.37-2.73; P <0.001) and 1.48 (95% CI: 1.11-1.97; P = 0.01) and any fibrosis with an OR of 3.31 (95% CI: 2.26-4.85; P < 0.001) and 1.66 (95% CI: 1.25-2.20; P < 0.001), respectively. When the models were adjusted for age, sex, BMI, ethnicity, and metabolic traits, the association between diabetes and family history of DM with NASH showed an increased adjusted OR of 1.76 (95% CI: 1.13-2.72; P < 0.001) and 1.34 (95% CI: 0.99-1.81; P = 0.06), respectively, and with any fibrosis with a significant adjusted OR of 2.57 (95% CI: 1.61-4.11; P < 0.0001) and 1.38 (95% CI: 1.02-1.87; P = 0.04), respectively. After excluding patients with personal history of diabetes, family history of DM was significantly associated with the presence of NASH and any fibrosis with an adjusted OR of 1.51 (95% CI: 1.01-2.25; P = 0.04) and 1.49 (95% CI: 1.01-2.20; P = 0.04), respectively.

CONCLUSIONS

Diabetes is strongly associated with risk of NASH, fibrosis, and advanced fibrosis. Family history of diabetes, especially among nondiabetics, is associated with NASH and fibrosis in NAFLD.

A comparison of survival and pathologic features of non-alcoholic steatohepatitis and hepatitis C virus patients with hepatocellular carcinoma

AIM: To compare the clinical outcome and pathologic features of non-alcoholic steatohepatitis (NASH) patients with hepatocellular carcinoma (HCC) and hepatitic C virus (HCV) patients with HCC (another group in which HCC is commonly seen) undergoing liver transplantation.

METHODS: Patients transplanted for HCV and NASH at our institution from January 2000 to April 2011 were analyzed. All explanted liver histology and pre-transplant liver biopsies were examined by two specialist liver histopathologists. Patient demographics, disease free survival, explant liver characteristics and HCC features (tumour number, cumulative tumour size, vascular invasion and differentiation) were compared between HCV and NASH liver transplant recipients.

RESULTS: A total of 102 patients with NASH and 283 patients with HCV were transplanted. The incidence of HCC in NASH transplant recipients was 16.7% (17/102). The incidence of HCC in HCV transplant recipients was 22.6% (64/283). Patients with NASH-HCC were statistically older than HCV-HCC patients (P < 0.001). A significantly higher proportion of HCV-HCC patients had vascular invasion (23.4% vs 6.4%, P = 0.002) and poorly differentiated HCC (4.7% vs 0%, P < 0.001) compared to the NASH-HCC group. A trend of poorer recurrence free survival at 5 years was seen in HCV-HCC patients compared to NASH-HCC who underwent a Liver transplantation (P = 0.11).

CONCLUSION: Patients transplanted for NASH-HCC appear to have less aggressive tumour features compared to those with HCV-HCC, which likely in part accounts for their improved recurrence free survival.

Overview and developments in noninvasive diagnosis of nonalcoholic fatty liver disease

High prevalence of non-alcoholic fatty liver disease (NAFLD) and very diverse outcomes that are related to disease form and severity at presentation have made the search for noninvasive diagnostic tools in NAFLD one of the areas with most intense development in hepatology today. Various methods have been investigated in the recent years, including imaging methods like ultrasound and magnetic resonance imaging, different forms of liver stiffness measurement, various biomarkers of necroinflammatory processes (acute phase reactants, cytokines, markers of apoptosis), hyaluronic acid and other biomarkers of liver fibrosis. Multicomponent tests, scoring systems and diagnostic panels were also developed with the purposes of differentiating non-alcoholic steatohepatitis from simple steatosis or discriminating between various fibrosis stages. In all of the cases, performance of noninvasive methods was compared with liver biopsy, which is still considered to be a gold standard in diagnosis, but is by itself far from a perfect comparative measure. We present here the overview of the published data on various noninvasive diagnostic tools, some of which appear to be very promising, and we address as well some of still unresolved issues in this interesting field.

Hyperresponsivity to low-dose endotoxin during progression to nonalcoholic steatohepatitis is regulated by leptin-mediated signaling

Although bacterial endotoxin, such as lipopolysaccharide (LPS), plays a key role in the pathogenesis of nonalcoholic steatohepatitis (NASH), detailed mechanisms of this pathogenesis remain unclear. Here, we demonstrate that upregulation of CD14 by leptin-mediated signaling is critical to hyperreactivity against endotoxin during NASH progression. Upregulation of CD14 in Kupffer cells and hyperreactivity against low-dose LPS were observed in high-fat diet (HFD)-induced steatosis mice, but not chow-fed-control mice. Hyperresponsivity against low-dose LPS led to accelerated NASH progression, including liver inflammation and fibrosis. Administering leptin in chow-fed mice caused increased hepatic expression of CD14 via STAT3 signaling, resulting in hyperreactivity against low-dose LPS without steatosis. In contrast, a marked decrease in hepatic CD14 expression was observed in leptin-deficient ob/ob mice, despite severe steatosis. Our results indicate that obesity-induced leptin plays a crucial role in NASH progression via enhanced responsivity to endotoxin, and we propose a mechanism of bacteria-mediated progression of NASH.

Silymarin suppresses hepatic stellate cell activation in a dietary rat model of non-alcoholic steatohepatitis: analysis of isolated hepatic stellate cells

Non-alcoholic steatohepatitis (NASH) is characterized by hepatocellular injury and initial fibrosis severity has been suggested as an important prognostic factor of NASH. Silymarin was reported to improve carbon tetrachloride-induced liver fibrosis and reduce the activation of hepatic stellate cells (HSC). We investigated whether silymarin could suppress the activation of HSCs in NASH induced by methionine- and choline-deficient (MCD) diet fed to insulin-resistant rats. NASH was induced by feeding MCD diet to obese diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Non-diabetic Long-Evans Tokushima Otsuka (LETO) rats were fed with standard chow and served as the control. OLETF rats were fed on either standard laboratory chow, or MCD diet or MCD diet mixed with silymarin. Histological analysis of the liver showed improved non-alcoholic fatty liver disease (NAFLD) activity score in silymarin-fed MCD-induced NASH. Silymarin reduced the activation of HSCs, evaluated by counting α-smooth muscle actin (SMA)-positive cells and measuring α-SMA mRNA expression in the liver lysates as well as in HSCs isolated from the experimental animals. Although silymarin decreased α₁-procollagen mRNA expression in isolated HSCs, the anti-fibrogenic effect of silymarin was not prominent so as to show significant difference under histological analysis. Silymarin increased the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and decreased tumor necrosis factor (TNF)-α mRNA expression in the liver. Our study suggested that the possible protective effect of silymarin in diet induced NASH by suppressing the activation of HSCs and disturbing the role of the inflammatory cytokine TNF-α.

Non-alcoholic Fatty Liver Disease: East Versus West

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver disease worldwide with prevalence ranging from 10% to 30% in various countries. It has become an important cause of unexplained rise in transaminases, cryptogenic cirrhosis, and cryptogenic hepatocellular carcinoma. Pathogenesis is related to obesity, insulin resistance, oxidative stress, lipotoxicity, and resultant inflammation in the liver progressing to fibrosis. Pharmacological treatment in patients with NAFLD is still evolving and the treatment of these patients rests upon lifestyle modification with diet and exercise being the cornerstones of therapy. While there are many similarities between patients with NAFLD from Asia and the West, there are certain features which make the patients with NAFLD from Asia stand apart. This review highlights the data on NAFLD from Asia comparing it with the data from the West.

Epidemiology and Natural History of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver disease burden across the world. By definition, although the histopathologic features of NAFLD are identical to that of alcoholic liver disease, its diagnosis requires absence of significant alcohol use and absence of other causes of chronic liver disease. We now know that NAFLD is not simply a disease of the Western world. It is manifested across the world, in varying rates, across gender, across varying ethnicities, and in its association with other host factors. In this review article, the definition of NAFLD, its spectrum, ranging from mild steatosis to hepatocellular injury and inflammation defined as non-alcoholic steatohepatitis (NASH) is discussed. Mild steatosis is generally a stable disease whereas NASH can be progressive. Based on current published literature, current incidence and prevalence of NAFLD and NASH are discussed. It is also accepted that these processes will continue to increase in prevalence with the rise of obesity, type II diabetes, and associated metabolic syndrome. Some of the risk factors have been well-established and are discussed. In addition, this review also presents emerging associations with other risk factors for NAFLD. Natural history of NAFLD is variable depending upon the histologic subtypes and other underlying comorbidities and is discussed in this review as well.

Animal models of nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat accumulates in the liver of a patient without a history of alcohol abuse. Nonalcoholic steatohepatitis (NASH), a severe form of NAFLD, can progress to liver cirrhosis and hepatocellular carcinoma. NAFLD is regarded as a hepatic manifestation of metabolic syndrome and incidence has been increasing worldwide in line with the increased prevalence of obesity, type 2 diabetes, and hyperlipemia. Animal models of NAFLD/NASH give crucial information, not only in elucidating pathogenesis of NAFLD/NASH but also in examining therapeutic effects of various agents. An ideal model of NAFLD/NASH should correctly reflect both hepatic histopathology and pathophysiology of human NAFLD/NASH. Animal models of NAFLD/NASH are divided into genetic, dietary, and combination models. In this paper, we review commonly used animal models of NAFLD/NASH referring to their advantages and disadvantages.

Omega-3 supplementation and non-alcoholic fatty liver disease: a systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) is a frequent accompaniment of obesity and insulin resistance. With the prevalence approaching 85% in obese populations, new therapeutic approaches to manage NAFLD are warranted. A systematic search of the literature was conducted for studies pertaining to the effect of omega-3 polyunsaturated fatty acid (PUFA) supplementation on NAFLD in humans. Primary outcome measures were liver fat and liver function tests: alanine aminotransferase (ALT) and aspartate aminotransferase [1]. Data were pooled and meta-analyses conducted using a random effects model. Nine eligible studies, involving 355 individuals given either omega-3 PUFA or control treatment were included. Beneficial changes in liver fat favoured PUFA treatment (effect size=-0.97, 95% CI: -0.58 to -1.35, p<0.001). A benefit of PUFA vs. control was also observed for AST (effect size=-0.97, 95% CI: -0.13 to -1.82, p=0.02). There was a trend towards favouring PUFA treatment on ALT but this was not significant (effect size=-0.56, 95% CI: -1.16 to 0.03, p=0.06). Sub-analyses of only randomised control trials (RCTs) showed a significant benefit for PUFA vs. control on liver fat (effect size=-0.96, 95% CI: -0.43 to -1.48, p<0.001), but not for ALT (p=0.74) or AST (p=0.28). There was significant heterogeneity between studies. The pooled data suggest that omega-3 PUFA supplementation may decrease liver fat, however, the optimal dose is currently not known. Well designed RCTs which quantify the magnitude of effect of omega-3 PUFA supplementation on liver fat are needed.

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

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

Nonalcoholic fatty liver disease: a review of the spectrum of disease, diagnosis, and therapy

Worldwide, there is an epidemic of obesity and overweight, with two-thirds of Americans affected. A strong association exists between excessive body weight and nonalcoholic fatty liver disease (NAFLD), the most common etiology of abnormal liver function tests. Nonalcoholic fatty liver disease is a spectrum of liver disease, from a "bland" fatty infiltration to chronic hepatitis (nonalcoholic steatohepatitis or NASH), that can result in cirrhosis and organ failure. With the increasing prevalence of obesity in the world, the proportion of people affected by NAFLD is only expected to be parallel. Although primarily noted in obese individuals, NAFLD has also been associated with a number of surgical procedures, metabolic conditions, and medications. NASH is commonly underdiagnosed as most affected patients are symptom free, and routine screening is not performed. Noninvasive diagnostic testing is not sensitive in diagnosis or staging the severity of disease. Fatty infiltration and oxidative injury to the hepatocytes are believed to be the major factors behind the progression of disease from simple fatty infiltration of the liver to chronic hepatitis. Understanding the inflammatory pathways involved in NASH is a subject of extensive research. Currently, few proven treatment options exist, and controlled weight reduction is the only safe modality recommended for treatment of NASH.

Natural course of nonalcoholic fatty liver disease in southern China: a prospective cohort study

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease, the natural course of which has not been well documented. This study aimed to perform a prospective cohort study to investigate NAFLD in a Chinese population.

METHODS

Using our previous epidemiological survey, 3543 patients were followed-up for a median of 4 years (range 3.6-4.8 years). Of these patients, 624 participated in a new survey. Interviews, physical examinations, biochemical tests and abdominal ultrasonography were repeated for these patient.

RESULTS

The annual incidence of NAFLD was 9.1% (male 7.3% vs female 9.7%, P=0.047). Among 117 NAFLD patients at baseline, 51 (43.6%) remained unchanged, 26 (22.2%) became worse, and 40 (34.2%) improved. Patients with simultaneous metabolic syndrome (MS) showed accelerated progression (P=0.026). For the NAFLD patients, both general annual mortality rates and cardiovascular disease deaths (both 0.54%) were significantly higher than those of patients without NAFLD (0.19% and 0.17%, P=0.005). Age and several variables related to MS were risk factors for NAFLD progression.

CONCLUSIONS

The incidence of NAFLD in southern China is relatively lower in comparison with that of the developed countries. Patients with NAFLD have a benign prognosis. Variables related to MS are risk factors for NAFLD occurrence and progression.

The utility of Xenon-133 liver scan in the diagnosis and management of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is an important and common condition affecting approximately 20% of the general population. Given the limitation of radiological investigations, diagnosis often requires a liver biopsy.

OBJECTIVE

To compare Xenon-133 (Xe-133) liver scanning with ultrasonography in the diagnosis of NAFLD.

METHODS

From January 2003 to February 2007, 258 consecutive patients with suspected NAFLD underwent Xe-133 liver scanning at Royal Victoria Hospital (Montreal, Quebec). Of these, 43 patients underwent ultrasonography and liver biopsy for the evaluation of NAFLD. Patients with other liver diseases and significant alcohol consumption were excluded. Two nuclear medicine physicians assessed liver Xe-133 uptake and measured the grade of steatosis using a standardized protocol. The degree of steatosis was determined from biopsy specimens assessed by two hepatopathologists.

RESULTS

NAFLD was identified by liver biopsy in 35 of 43 patients (81.4%). Xe-133 scan demonstrated 94.3% sensitivity (95% CI 81.4% to 98.4%) and 87.5% specificity (95% CI 52.9% to 99.4%) for the presence of NAFLD. The positive and negative predictive values for detection of steatosis by Xe-133 scan were 97.1% (95% CI 85.1% to 99.8%) and 77.8% (95% CI 45.3% to 93.7%), respectively. The positive and negative likelihood ratios were 7.54 (95% CI 1.20 to 47.26) and 0.07 (95% CI 0.02 to 0.26), respectively. Two patients with NAFLD (5.7%) who had a negative Xe-133 scan result had histologically mild steatosis (<10%). The grade of steatosis on liver biopsy was highly correlated with the results of the Xe-133 scan (r=0.87; P<0.001). The sensitivity and specificity of ultrasound in diagnosing steatosis were 62.9% and 75%, respectively.

CONCLUSION

Xe-133 liver scan proved to be a safe, reliable, noninvasive method for diagnosing and quantifying hepatic steatosis, and was superior to ultrasound.

Inflammation and fibrogenesis in steatohepatitis

Nonalcoholic fatty liver disease consists of a range of disorders characterized by excess accumulation of triglyceride within the liver. Whereas simple steatosis is clinically benign, nonalcoholic steatohepatitis (NASH) often progresses to cirrhosis. Inflammation and fibrogenesis are closely inter-related and are major targets of NASH research. Experimental data have shown that inflammation in NASH is caused by insulin resistance, systemic lipotoxicity due to overnutrition, lipid metabolites, the production of proinflammatory cytokines and adipokines by visceral adipose tissue, gut-derived bacteria, and oxidative stress. In NASH-associated fibrosis, the principal cell type responsible for extracellular matrix production is recognized as the hepatic stellate cell. Although the fibrotic mechanisms underlying NASH are largely similar to those observed in other chronic liver diseases, the altered patterns of circulating adipokines, the generation of oxidative stress, and the hormonal profile associated with the metabolic syndrome might play unique roles in the fibrogenesis associated with the disease. Information on the basic pathogenesis of NASH with a focus on the generation of inflammation and fibrosis will be discussed.

Low clinical relevance of the nonalcoholic fatty liver disease activity score (NAS) in predicting fibrosis progression

BACKGROUND/AIMS

The nonalcoholic fatty liver disease (NAFLD) activity score (NAS) is a newly proposed system to grade the necroinflammatory activity in liver biopsies of NAFLD patients. This study evaluates the usefulness of the NAS in predicting clinical deterioration and fibrosis progression in NAFLD.

METHODS

One hundred and twenty-nine patients with biopsy-proven NAFLD were included in a long-term histological follow-up study. Clinical course and change in fibrosis stage were compared between nonalcoholic steatohepatitis (NASH), "borderline NASH," and "not NASH" patients. Significant fibrosis progression was defined as progression of more than one fibrosis stage or development of end-stage liver disease during follow-up.

RESULTS

Eighty-eight patients accepted reevaluation and 68 underwent repeat liver biopsy. Mean time between biopsies was 13.8 ± 1.2 years (range 10.3-16.3). At baseline, NASH was diagnosed in 2 (1.6%) patients, and at follow-up, in 1 (1.5%) patient. A trend toward higher baseline NAS was seen in patients (n = 7) who developed end-stage liver disease (3.1 ± 0.9 vs. 2.2 ± 1.0; p = 0.050). Baseline NAS was associated with progressive disease in a univariate binary logistic regression analysis (p = 0.024), but no difference was seen in the multivariate analysis including the NAS, portal inflammation, and perisinusoidal fibrosis. Moreover, 18% of patients without NASH progressed significantly in fibrosis stage.

CONCLUSIONS

The ability of the NAS to predict progression of NAFLD is poor. The clinical usefulness of the score is limited due to the significant overlap in clinical development between NAS score groups. To use the NAS as endpoint in treatment trial is not justified.

Hepatic steatosis at 1 year is an additional predictor of subsequent fibrosis severity in liver transplant recipients with recurrent hepatitis C virus

Recurrent hepatitis C virus (HCV) is the most common cause of graft loss for HCV-infected recipients of liver transplantation (LT). Diabetes mellitus (DM) has been associated with increased rates of fibrosis progression, but whether steatosis affects post-LT outcomes independently of DM is unclear. Using a retrospective cohort of HCV-infected LT recipients, we determined the prevalence of hepatic steatosis and evaluated the relationship between steatosis on index biopsy 1 year after LT (± 6 months) and the severity of the subsequent fibrosis. One hundred fifty-two LT recipients with HCV were followed up for a median of 2.09 years (range = 0.13-6.17 years) after index biopsy; the median number of biopsy procedures per patient after index biopsy was 2 (range = 1-6). Steatosis (≥ 5%) was present in 45 individuals (29.6%) according to index biopsy samples taken 1 year after LT; the steatosis was mild (grade 1) in 80% of the patients. In the multivariate analysis, the presence of steatosis 1 year after LT was positively associated with HCV genotype 3 [odds ratio (OR) = 3.60, P = 0.02], older donor age (OR = 1.03, P = 0.04), and pre-LT hypertension (OR = 3.29, P = 0.009). Two years after index biopsy, the cumulative rate of significant fibrosis (F2-F4 on the Ludwig-Batts scale) was 49% in the patients with steatosis at 1 year and 24% in the patients without steatosis (P = 0.003). In the multivariate analysis, steatosis at 1 year was an independent predictor of subsequent F2 to F4 fibrosis (HR = 2.63, 95% CI = 1.49-4.63). Steatosis was a stronger predictor of fibrosis in the setting of sirolimus use (hazard ratio = 9.38, 95% confidence interval = 1.37-64.16, P = 0.02). In conclusion, steatosis is frequent in the early post-LT period, and steatosis within the first year after LT is a marker of a higher risk of fibrosis progression in HCV-infected patients.

Metabolic syndrome and hepatic resection: improving outcome

OBJECTIVE

A review of the peri-operative risk associated with hepatic resection in patients with metabolic syndrome (MetS) and identification of measures for the improvement of cardiometabolic disturbances and liver-related mortality.

BACKGROUND

MetS and its hepatic manifestation non-alcoholic fatty liver disease (NAFLD) are associated with an increased operative mortality in spite of a significant improvement in peri-operative outcome after hepatic resection.

METHODS

A review of the English literature on MetS, liver resection and steatosis was performed from 1980 to 2011 using the MEDLINE and PubMed databases.

RESULTS

MetS is a predictor of NAFLD and patients with multiple metabolic risk factors may harbour non-alcoholic steatohepatitis (NASH) predictive of operative and cardiovascular mortality. Pre-operative diagnosis of unsuspected NASH with the selective use of a liver biopsy can modify the operative strategy by limiting the extent of hepatic resection, avoiding or altering the pre-operative chemotherapy regimen and the utilization of portal vein embolization. Thiazolidinediones are therapeutic for MetS and NASH and Vitamin E for active NASH; however, their utility in improving the peri-operative outcome after hepatic resection is unknown. A short-term regimen for weight loss improves post-operative patient and liver-related outcomes in patients with >30% steatosis. Cardiovascular disease associated with MetS or NAFLD should be managed aggressively. Peri-operative measures to minimize thrombotic events and acute renal injury secondary to the pro-inflammatory, prothrombotic state of MetS may further improve the outcome.

CONCLUSION

Potential candidates for hepatic resection should be screened for MetS as the pre-operative identification of NASH, short-term treatment of significant steatosis, cardiovascular risk assessment and optimization of each component of MetS may improve the peri-operative outcome in this high-risk subset of patients.

Non-alcoholic fatty liver disease and mortality among US adults: prospective cohort study

OBJECTIVE

To evaluate the association between non-alcoholic fatty liver disease and all cause and cause specific mortality in a representative sample of the US general population.

DESIGN

Prospective cohort study.

SETTING

US Third National Health and Nutrition Examination Survey (NHANES III: 1988-94) with follow-up of mortality to 2006.

PARTICIPANTS

11,371 adults aged 20-74 participating in the Third National Health and Nutrition Examination Survey, with assessment of hepatic steatosis.

MAIN OUTCOME MEASURE

Mortality from all causes, cardiovascular disease, cancer, and liver disease (up to 18 years of follow-up).

RESULTS

The prevalence of non-alcoholic fatty liver disease with and without increased levels of liver enzymes in the population was 3.1% and 16.4%, respectively. Compared with participants without steatosis, those with non-alcoholic fatty liver disease but normal liver enzyme levels had multivariate adjusted hazard ratios for deaths from all causes of 0.92 (95% confidence interval 0.78 to 1.09), from cardiovascular disease of 0.86 (0.67 to 1.12), from cancer of 0.92 (0.67 to 1.27), and from liver disease of 0.64 (0.12 to 3.59). Compared with participants without steatosis, those with non-alcoholic fatty liver disease and increased liver enzyme levels had adjusted hazard ratios for deaths from all causes of 0.80 (0.52 to 1.22), from cardiovascular disease of 0.59 (0.29 to 1.20), from cancer of 0.53 (0.26 to 1.10), and from liver disease of 1.17 (0.15 to 8.93).

CONCLUSIONS

Non-alcoholic fatty liver disease was not associated with an increased risk of death from all causes, cardiovascular disease, cancer, or liver disease.

Intravenous administration of multipotent stromal cells prevents the onset of non-alcoholic steatohepatitis in obese mice with metabolic syndrome

BACKGROUND & AIMS

Metabolic syndrome is secondary to obesity and characterized by dyslipidemia, insulin resistance, and hypertension. Non-alcoholic fatty liver disease is its hepatic manifestation, whose progression-limiting step is non-alcoholic steatohepatitis (NASH). The latter is characterized by lipid accumulation, hepatocyte damage, leukocyte infiltration, and fibrosis. NASH is a prodrome to cirrhosis and hepatocellular carcinoma. Multipotent stromal cells (MSCs) have been shown to be immunomodulatory and contribute to liver regeneration in acute failure conditions. Our aim was to evaluate whether MSC administration prevents the onset of NASH in obese mice with metabolic syndrome.

METHODS

C57BL/6 mice were chronically fed with high-fat diet. At week 33, mice received intravenously either the vehicle (obese untreated) or two doses of 0.5×10(6) syngeneic MSCs (obese MSC-treated). Four months later, liver function and structure, and metabolic syndrome markers were assessed. The persistence of donor MSCs(GFP) in obese mice was evaluated 17 weeks after their administration.

RESULTS

Obese untreated mice presented high plasma levels of hepatic enzyme, hepatomegaly, liver fibrosis, inflammatory cell infiltration, and hepatic triglyceride accumulation. Furthermore, they showed high expression levels of fibrosis markers and pro-inflammatory cytokines. By contrast, obese MSC-treated mice only presented steatosis. Mice kept obese, hypercholesterolemic, hyperglycemic, and insulin resistant irrespective of whether they received MSCs or not. Donor MSCs(GFP) were found in liver, bone marrow, heart, and kidney of obese mice.

CONCLUSIONS

MSC administration prevents the onset of NASH in obese mice. Observed hepatoprotection is not related to a reversion of the metabolic syndrome but to the preclusion of the inflammatory process.

Hepatic fat quantification using chemical shift MR imaging and MR spectroscopy in the presence of hepatic iron deposition: validation in phantoms and in patients with chronic liver disease

PURPOSE

To compare the accuracy of four chemical shift magnetic resonance imaging (MRI) (CS-MRI) analysis methods and MR spectroscopy (MRS) with and without T2-correction in fat quantification in the presence of excess iron.

MATERIALS AND METHODS

CS-MRI with six opposed- and in-phase acquisitions and MRS with five-echo acquisitions (TEs of 20, 30, 40, 50, 60 msec) were performed at 1.5 T on phantoms containing various fat fractions (FFs), on phantoms containing various iron concentrations, and in 18 patients with chronic liver disease. For CS-MRI, FFs were estimated with the dual-echo method, with two T2*-correction methods (triple- and multiecho), and with multiinterference methods that corrected for both T2* and spectral interference effects. For MRS, FF was estimated without T2-correction (single-echo MRS) and with T2-correction (multiecho MRS).

RESULTS

In the phantoms, T2*- or T2-correction methods for CS-MRI and MRS provided unbiased estimations of FFs (mean bias, -1.1% to 0.5%) regardless of iron concentration, whereas the dual-echo method (-5.5% to -8.4%) and single-echo MRS (12.1% to 37.3%) resulted in large biases in FFs. In patients, the FFs estimated with triple-echo (R = 0.98), multiecho (R = 0.99), and multiinterference (R = 0.99) methods had stronger correlations with multiecho MRS FFs than with the dual-echo method (R = 0.86; P ≤ 0.011). The FFs estimated with multiinterference method showed the closest agreement with multiecho MRS FFs (the 95% limit-of-agreement, -0.2 ± 1.1).

CONCLUSION

T2*- or T2-correction methods are effective in correcting the confounding effects of iron, enabling an accurate fat quantification throughout a wide range of iron concentrations. Spectral modeling of fat may further improve the accuracy of CS-MRI in fat quantification.

An Endocrine Perspective of Nonalcoholic Fatty Liver Disease (NAFLD)

Endocrinologists are encountering patients with obesity-related complications such as metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) on a daily basis. Nonalcoholic fatty liver disease (NAFLD) is a liver condition characterized by insulin resistance, hepatic steatosis and frequently T2DM. This is now the most common chronic liver condition in adults and is present in the majority of obese subjects. Liver fat accumulation may range from simple steatosis to severe steatohepatitis with hepatocyte necroinflammation (or nonalcoholic steatohepatitis [NASH]). Although the natural history is incompletely understood, NAFLD may lead to serious medical consequences ranging from cirrhosis and hepatocellular carcinoma to earlier onset of T2DM and cardiovascular disease (CVD). The diagnosis of NAFLD may be challenging because signs and symptoms are frequently absent or nonspecific, and thus easily missed. Liver aminotransferases may be helpful if elevated, but most times are normal in the presence of the disease. Liver imaging may assist in the diagnosis (ultrasound or MRI and spectroscopy) but a definitive diagnosis of NASH still requires a liver biopsy. This may change in the near future as novel biomarkers become available. Treatment of NAFLD includes aggressive management of associated cardiovascular risk factors and many times control of T2DM. Pioglitazone and vitamin E appear promising for patients with NASH, although long-term studies are unavailable. In summary, this review hopes to address the common clinical dilemmas that endocrinologists face in the diagnosis and management of NAFLD and increase awareness of a potentially serious medical condition.

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

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

Diagnostic accuracy and reliability of ultrasonography for the detection of fatty liver: a meta-analysis

Ultrasonography is a widely accessible imaging technique for the detection of fatty liver, but the reported accuracy and reliability have been inconsistent across studies. We aimed to perform a systematic review and meta-analysis of the diagnostic accuracy and reliability of ultrasonography for the detection of fatty liver. We used MEDLINE and Embase from October 1967 to March 2010. Studies that provided cross-tabulations of ultrasonography versus histology or standard imaging techniques, or that provided reliability data for ultrasonography, were included. Study variables were independently abstracted by three reviewers and double checked by one reviewer. Forty-nine (4720 participants) studies were included for the meta-analysis of diagnostic accuracy. The overall sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of ultrasound for the detection of moderate-severe fatty liver, compared to histology (gold standard), were 84.8% (95% confidence interval: 79.5-88.9), 93.6% (87.2-97.0), 13.3 (6.4-27.6), and 0.16 (0.12-0.22), respectively. The area under the summary receiving operating characteristics curve was 0.93 (0.91-0.95). Reliability of ultrasound for the detection of fatty liver showed kappa statistics ranging from 0.54 to 0.92 for intrarater reliability and from 0.44 to 1.00 for interrater reliability. Sensitivity and specificity of ultrasound was similar to that of other imaging techniques (i.e., computed tomography or magnetic resonance imaging). Statistical heterogeneity was present even after stratification for multiple clinically relevant characteristics.

CONCLUSION

Ultrasonography allows for reliable and accurate detection of moderate-severe fatty liver, compared to histology. Because of its low cost, safety, and accessibility, ultrasound is likely the imaging technique of choice for screening for fatty liver in clinical and population settings.

Nonalcoholic fatty liver disease: pharmacologic and surgical options

The last decade has seen many studies examining the prevalence and natural history of NAFLD in the United States and it is clear that this disease is likely to be an important cause of liver-related morbidity in the future. Several pharmacologic therapies have shown some promise; currently, vitamin E and insulin-sensitizing agents such as pioglitazone can be considered in appropriate cases. Conservative measures to promote weight loss still have a role to play, but the obesity epidemic in the Western World has reached such proportions that bariatric surgery is proving to be an attractive option for patients with a BMI greater than 35 to 40 kg/m2. Well-designed prospective studies are required to ensure that all of these therapies are safe and effective in the long term. Newer agents will likely be investigated as the pathogenesis of NAFLD and fibrosis progression in NASH are further elucidated.