Is NASH underdiagnosed among African Americans?

Racial Differences in Liver Fibrosis Burden

BACKGROUND & AIMS

Liver histology is the classic method for staging the severity of liver fibrosis, which in turn is an important predictor of clinical outcome. Here, we have hypothesized that the susceptibility to develop fibrosis varies among racial groups.

METHODS

We examined the histology of all patients over 18 years of age who underwent liver biopsy at the Medical University of South Carolina from 1/1/2013 to 7/1/2021. Patients with malignancy, liver metastases, or missing data were excluded. Fibrosis was quantified using the Batts-Ludwig system (F0 = no fibrosis to F4 = histological cirrhosis). Racial groups were propensity matched based on age, gender, diabetes, alcohol consumption, and CDC/ATSDR Social Vulnerability Index Themes to mitigate the risk of selection bias.

RESULTS

We identified 1101 patients with liver biopsy histological fibrosis scores. The cohort included 23% Black patients. After propensity matching, Black patients were significantly more likely to have Hepatitis C (73/228 (32%) vs 45/228 (20%), p < 0.001) and autoimmune hepatitis (34/228 (15%) vs 6/228 (3%), p < 0.001) than White patients, while White patients were significantly more likely to have metabolic dysfunction associated steatotic liver disease (71/228 (31%) vs 18/228 (8%), p < 0.001). White patients were significantly more likely to have cirrhosis than Black patients (White - 89/228 (39%) vs Black - 68/228 (30%), p < 0.05).

CONCLUSION

White patients had a greater overall burden of advanced fibrosis (F4/cirrhosis) than Black patients, independent of etiology. The data suggest that fibrosis risk and/or progression may be worse in White than Black patients.

Surging Liver Transplantation for Nonalcoholic Steatohepatitis from 2000-2022: A National Database Study

OBJECTIVES

Our aim was to provide an up-to-date, large-scale overview of the trends and clinicodemographics for NASH LTs performed in the United States compared with all other LT indications between 2000 and 2022. We also examined the demographic factors that will predict future demand for NASH LT.

METHODS

Our analysis of NASH LT from the Organ Procurement & Transplantation Network database spanning 2000-2022 consisted primarily of descriptive statistics and hypothesis testing with corrections for multiple testing when necessary. Trend lines and linear correlations were also explored.

RESULTS

NASH LTs have experienced a remarkable surge, escalating from 0.12% of all LTs in 2000 to a substantial 14.7% in 2022, marking a 100-fold increase. Examining demographic trends, a significant proportion of NASH LTs recipients fall within the 50- to 64-year-old age group. Moreover, 52% of these recipients concurrently exhibit type 2 diabetes mellitus, a notably higher percentage than the 19% observed in all LT recipients. Type 2 diabetes mellitus emerges as a prominent risk factor for NASH progressing to end-stage liver disease. The phenomenon of repeat transplantation is noteworthy; although 6% of all LTs necessitate repeat procedures, this figure dramatically drops to 0.6% for NASH LTs. Ethnic disparities are apparent, with African Americans representing a mere 2% of NASH LT recipients, significantly lower than their representation in the overall population. Regionally, the East Coast has a higher proportion of NASH LT recipients compared with waitlist additions. This trend holds true across demographics.

CONCLUSIONS

Our findings underscore the need for increased resources, particularly for minority, uninsured, or noncitizen individuals requiring LT for NASH. This analysis provides valuable insights into the dynamic landscape of LTs in the context of NASH, shaping the trajectory of medical interventions in the 21st century.

Metabolic Dysfunction-Associated Steatohepatitis and Progression to Hepatocellular Carcinoma: A Literature Review

The prevalence of metabolic-associated fatty liver disease (MAFLD) is increasing globally due to factors such as urbanization, obesity, poor nutrition, sedentary lifestyles, healthcare accessibility, diagnostic advancements, and genetic influences. Research on MAFLD and HCC risk factors, pathogenesis, and biomarkers has been conducted through a narrative review of relevant studies, with a focus on PubMed and Web of Science databases and exclusion criteria based on article availability and language. Steatosis marks the early stage of MASH advancement, commonly associated with factors of metabolic syndrome such as obesity and type 2 diabetes. Various mechanisms, including heightened lipolysis, hepatic lipogenesis, and consumption of high-calorie diets, contribute to the accumulation of lipids in the liver. Insulin resistance is pivotal in the development of steatosis, as it leads to the release of free fatty acids from adipose tissue. Natural compounds hold promise in regulating lipid metabolism and inflammation to combat these conditions. Liver fibrosis serves as a significant predictor of MASH progression and HCC development, underscoring the need to target fibrosis in treatment approaches. Risk factors for MASH-associated HCC encompass advanced liver fibrosis, older age, male gender, metabolic syndrome, genetic predispositions, and dietary habits, emphasizing the requirement for efficient surveillance and diagnostic measures. Considering these factors, it is important for further studies to determine the biochemical impact of these risk factors in order to establish targeted therapies that can prevent the development of HCC or reduce progression of MASH, indirectly decreasing the risk of HCC.

Contribution of a genetic risk score to ethnic differences in fatty liver disease

BACKGROUND AND AIMS

Susceptibility to fatty liver disease (FLD) varies among individuals and between racial/ethnic groups. Several genetic variants influence FLD risk, but whether these variants explain racial/ethnic differences in FLD prevalence is unclear. We examined the contribution of genetic risk factors to racial/ethnic-specific differences in FLD.

METHODS

A case-control study comparing FLD patients (n = 1194) and population-based controls (n = 3120) was performed. Patient characteristics, FLD risk variants (PNPLA3-rs738409 + rs6006460, TM6SF2-rs58542926, HSD17B13-rs80182459 + rs72613567, MBOAT7/TMC4-rs641738, and GCKR-rs1260326) and a multi-locus genetic risk score (GRS) were examined. The odds of FLD for individuals with different risk factor burdens were determined.

RESULTS

Hispanics and Whites were over-represented (56% vs. 38% and 36% vs. 29% respectively) and Blacks under-represented (5% vs. 23%) among FLD patients, compared to the population from which controls were selected (p < .001). Among cases and controls, Blacks had a lower and Hispanics a greater, net number of risk alleles than Whites (p < .001). GRS was associated with increased odds of FLD (OR_Q5vsQ1  = 8.72 [95% CI = 5.97-13.0], p = 9.8 × 10^-28 ), with the association being stronger in Hispanics (OR_Q5vsQ1  = 14.8 [8.3-27.1]) than Blacks (OR_Q5vsQ1  = 3.7 [1.5-11.5], P-interaction = 0.002). After accounting for GRS, the odds of FLD between Hispanics and Whites did not differ significantly (OR = 1.06 [0.87-1.28], p = .58), whereas Blacks retained much lower odds of FLD (OR = 0.21, [0.15-0.30], p < .001).

CONCLUSIONS

Blacks had a lower and Hispanics a greater FLD risk allele burden than Whites. These differences contributed to, but did not fully explain, racial/ethnic differences in FLD prevalence. Identification of additional factors protecting Blacks from FLD may provide new targets for prevention and treatment of FLD.

Cell Autophagy in NASH and NASH-Related Hepatocellular Carcinoma

Autophagy, a cellular self-digestion process, involves the degradation of targeted cell components such as damaged organelles, unfolded proteins, and intracellular pathogens by lysosomes. It is a major quality control system of the cell and plays an important role in cell differentiation, survival, development, and homeostasis. Alterations in the cell autophagic machinery have been implicated in several disease conditions, including neurodegeneration, autoimmunity, cancer, infection, inflammatory diseases, and aging. In non-alcoholic fatty liver disease, including its inflammatory form, non-alcoholic steatohepatitis (NASH), a decrease in cell autophagic activity, has been implicated in the initial development and progression of steatosis to NASH and hepatocellular carcinoma (HCC). We present an overview of autophagy as it occurs in mammalian cells with an insight into the emerging understanding of the role of autophagy in NASH and NASH-related HCC.

Portrait of Regional Trends in Liver Transplantation for Nonalcoholic Steatohepatitis in the United States

INTRODUCTION

Nonalcoholic steatohepatitis (NASH) is one of the most common etiologies of liver transplantation (LT) in the United States. We investigated regional trends in waitlist candidates, LT rates, and recipient survival among patients with NASH.

METHODS

Using the United Network for Organ Sharing database by Organ Procurement and Transplantation Network regions, we investigated waitlist registration, LT rates, and survival for NASH between January 2004 and December 2019.

RESULTS

The absolute number and percentage of total LT performed for NASH increased substantially in all Organ Procurement and Transplantation Network regions. In 2019, region 11 had the highest percentage of NASH-related LT with 31.4% followed by region 10 (25.3%) and region 8 (23.1%). Between 2015 and 2019, region 5 had the highest rising percentage in LT for NASH at 208%, followed by region 1 (194%) and region 4 (183%). The proportion of NASH hepatocellular carcinoma (NASH-HCC) was the highest in region 9 at 37.7% and lowest in region 10 (19.2%), region 3 (20.6%), and region 11 (20.8%). In multivariate analysis, diabetes (HR 1.18, P < 0.001), dialysis before LT (hazard ratio [HR] 1.53, P < 0.001), HCC (HR 1.19, P < 0.00), portal vein thrombosis (HR 1.24, P < 0.001), donor age (HR 1.026, P = 0.03), and recipient age (HR 1.24, P = <0.001) were associated with worse survival.

DISCUSSION

LT for patients with NASH has dramatically increased across all regions since 2004, but with substantial heterogeneity among regions in the proportion with HCC and post-LT survival. Identifying contributing factors to these regional differences is warranted.

What Do We Know about Inequalities in NAFLD Distribution and Outcomes? A Scoping Review

With prevalence high and rising given the close relationship with obesity and diabetes mellitus, non-alcoholic fatty liver disease (NAFLD) is progressively becoming the most common chronic liver condition worldwide. However, little is known about the health inequalities in NAFLD distribution and outcomes. This review aims to analyze health inequalities in NAFLD distribution globally and to assess the health disparities in NAFLD-related outcomes. We conducted a scoping review of global health inequalities in NAFLD distribution and outcomes according to gender/sex, ethnicity/race, and socioeconomic position from PubMed's inception to May 2021. Ultimately, 20 articles were included in the review, most (75%) of them carried out in the United States. Males were found to have a higher NAFLD prevalence (three articles), while available evidence suggests that women have an overall higher burden of advanced liver disease and complications (four articles), whereas they are less likely to be liver-transplanted once cirrhosis develops (one article). In the US, the Hispanic population had the highest NAFLD prevalence and poorer outcomes (seven articles), whereas Whites had fewer complications than other ethnicities (two articles). Patients with low socioeconomic status had higher NAFLD prevalence (four articles) and a higher likelihood of progression and complications (five articles). In conclusion, globally there is a lack of studies analyzing NAFLD prevalence and outcomes according to various axes of inequality through joint intersectional appraisals, and most studies included in our review were based on the US population. Available evidence suggests that NAFLD distribution and outcomes show large inequalities by social group. Further research on this issue is warranted.

Epidemiology, risk factors, social determinants of health, and current management for non-alcoholic fatty liver disease in sub-Saharan Africa

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease globally and is estimated to affect approximately 25% of the world's population. Data about the prevalence and incidence of NAFLD in Africa are scarce, but the prevalence is estimated to be 13·5% for the general population. This is likely to be an underestimate considering the increasing burden of non-communicable diseases, particularly the rising prevalence of obesity and type 2 diabetes, driven by the overlapping challenges of food insecurity, nutritional transition, and associated increased consumption of calorie-dense foods. Establishing the true prevalence of NAFLD, raising public awareness around the risk factors behind the increase in NAFLD, and proactively addressing all components of metabolic syndrome will be important to combat this silent epidemic, which will have long-term health-care costs and economic consequences for the region.

Prospective evaluation of the prevalence of non-alcoholic fatty liver disease and steatohepatitis in a large middle-aged US cohort

BACKGROUND & AIMS

Large prospective studies to establish the prevalence of non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH), are lacking. We prospectively assessed the prevalence and severity of NAFLD/NASH in a cohort of asymptomatic middle-aged Americans attending a colonoscopy class at a gastroenterology clinic.

METHODS

Screening for NAFLD was performed using magnetic resonance (MR)-based LiverMultiScan® proton density fat fraction (LMS-PDFF). MR exams also included corrected T1 and elastography for liver stiffness measurement (LSM). FibroScan® was also used to measure LSM. Participants with predetermined abnormal imaging parameters were offered a liver biopsy. Biopsies were read in a blinded fashion with results based on the consensus by 2 expert pathologists. The prevalence of NAFLD was determined by PDFF ≥5% or by histological diagnosis of NAFLD (if biopsy data were available). The prevalence of NASH was defined by biopsy.

RESULTS

Of 835 participants, 664 met the inclusion and exclusion criteria. The mean age was 56 ± 6.4 years, 50% were male, the mean BMI was 30.48 ± 5.46 kg/m², and 52% were obese. The prevalence of NAFLD was 38% (95% CI 34-41%) and the prevalence of NASH was 14% (95% CI 12-17%). While no patient had cirrhosis on biopsy, significant fibrosis (F ≥2) was present in 5.9% (95% CI 4-8%) and bridging fibrosis in 1.6% (95% CI 1-3%). In a multivariable analysis, factors associated with the presence of NASH were race, obesity, and diabetes.

CONCLUSION

Using state-of-the-art liver imaging modalities and reference biopsy, this study establishes an overall prevalence of NAFLD of 38% and NASH by biopsy of 14% in this cohort of asymptomatic middle-aged US adults.

LAY SUMMARY

There are no prospective studies to determine how common is nonalcoholic steatohepatitis (NASH), the severe form of non-alcoholic fatty liver disease (NAFLD). In a large number of asymptomatic middle-aged Americans, we used a combination of state-of-the-art liver imaging methods and liver biopsy to prospectively determine the prevalence of NAFLD and NASH. NAFLD was diagnosed in 38%, NASH in 14%, and significant liver fibrosis in 6% of asymptomatic middle-aged Americans.

Emerging risk factors for nonalcoholic fatty liver disease associated hepatocellular carcinoma

Worldwide, nonalcoholic fatty liver disease (NAFLD) has reached epidemic proportions and in parallel, hepatocellular carcinoma (HCC) has become one of the fastest growing cancers. Epidemiological studies have not only shed light on the prevalence and incidence of the disease but have also unmasked important environmental risk factors, including the role of diabetes and dyslipidemia in disease pathogenesis. Genetic association studies have identified single nucleotide polymorphisms implicated in NAFLD-HCC, many of which are part of lipid metabolism pathways. Through these clinical studies and subsequently, translational and basic research, the role of statins as a chemoprotective agent has also emerged with ongoing clinical trials assessing their utility in HCC prevention and treatment. In this review, we summarize the recent epidemiological studies describing the burden of NAFLD-HCC in different patient populations and countries. We discuss the genetic and environmental risk factors for NAFLD-HCC and highlight the chemoprotective role of statins and aspirin. We also summarize what is known about NAFLD-HCC in the cirrhosis and non-cirrhosis populations and briefly address the role of surveillance in NAFLD-HCC patients.

Genetic Risk Factors and Disease Modifiers of Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease is strongly associated with obesity and the metabolic syndrome, but genetic factors also contribute to disease susceptibility. Human genetic studies have identified several common genetic variants contributing to nonalcoholic fatty liver disease initiation and progression. These findings have provided new insights into the pathogenesis of nonalcoholic fatty liver disease and opened up new avenues for the development of therapeutic interventions. In this review, we summarize the current state of knowledge about the genetic determinants of nonalcoholic fatty liver disease, focusing on the most robustly validated genetic risk factors and on recently discovered modifiers of disease progression.

Molecular Mechanisms: Connections between Nonalcoholic Fatty Liver Disease, Steatohepatitis and Hepatocellular Carcinoma

Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), causes hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The patatin-like phospholipase-3 (PNPLA3) I148M sequence variant is one of the strongest genetic determinants of NAFLD/NASH. PNPLA3 is an independent risk factor for HCC among patients with NASH. The obesity epidemic is closely associated with the rising prevalence and severity of NAFLD/NASH. Furthermore, metabolic syndrome exacerbates the course of NAFLD/NASH. These factors are able to induce apoptosis and activate immune and inflammatory pathways, resulting in the development of hepatic fibrosis and NASH, leading to progression toward HCC. Small intestinal bacterial overgrowth (SIBO), destruction of the intestinal mucosa barrier function and a high-fat diet all seem to exacerbate the development of hepatic fibrosis and NASH, leading to HCC in patients with NAFLD/NASH. Thus, the intestinal microbiota may play a role in the development of NAFLD/NASH. In this review, we describe recent advances in our knowledge of the molecular mechanisms contributing to the development of hepatic fibrosis and HCC in patients with NAFLD/NASH.

Non-alcoholic fatty liver disease in Africa: a hidden danger

There is a dearth of data on the burden and spectrum of non-alcoholic fatty liver disease (NAFLD) in African populations. The limited available information suggests that the prevalence of NAFLD in the general population is lowest for the Africa region. However, this is likely to be an underestimate and also does not take into consideration the long-term impact of rising rates of obesity, type-2 diabetes mellitus (T2DM) and high human immunodeficiency virus infection burden in Africa. A racial disparity in the prevalence of NAFLD has been observed in some studies but remains unexplained. There is an absence of data from population-based studies in Africa and this highlights the need for such studies, to reliably define the health service needs for this region. Screening for NAFLD at a population-based level using ultrasound is perhaps the ideal method for resource-poor settings because of its relative cost-effectiveness. What is required as a priority from Africa, are well-designed epidemiologic studies that screen for NAFLD in the general population as well as high-risk groups such as patients with T2DM or obesity.

Ethnic differences and heterogeneity in genetic and metabolic makeup contributing to nonalcoholic fatty liver disease

Obesity is the most prevalent noncommunicable disease in the 21st century, associated with triglyceride deposition in hepatocytes leading to nonalcoholic fatty liver disease (NAFLD). NAFLD is now present in around a third of the world's population. Epidemiological studies have concluded that ethnicity plays a role in complications and treatment response. However, definitive correlations of ethnicity with NAFLD are thoroughly under-reported. A comprehensive review was conducted on ethnic variation in NAFLD patients and its potential role as a crucial effector in complications and treatment response. The highest NAFLD prevalence is observed in Hispanic populations, exhibiting a worse disease progression. In contrast, African-Caribbeans exhibit the lowest risk, with less severe steatosis and inflammation, lower levels of triglycerides, and less metabolic derangement, but conversely higher prevalence of insulin resistance. The prevalence of NAFLD in Asian cohorts is under-reported, although reaching epidemic proportions in these populations. The most well-documented NAFLD patient population is that of Caucasian ethnicity, especially from the US. The relative paucity of available literature suggests there is a vital need for more large-scale multi-ethnic clinical cohort studies to determine the incidence of NAFLD within ethnic groups. This would improve therapy and drug development, as well as help identify candidate gene mutations which may differ within the population based on ethnic background.

Pediatric Nonalcoholic Fatty Liver Disease in New York City: An Autopsy Study

OBJECTIVE

To assess the prevalence and severity of nonalcoholic liver disease (NAFLD) in children in a diverse population sample in New York City.

STUDY DESIGN

Liver specimens were examined from children 2-19 years old who died of unexpected causes within 48 hours of medical presentation and underwent autopsy in New York City from 2005 to 2010. Records were reviewed for age, sex, weight, height, and race. Two hepatopathologists evaluated each liver specimen to determine pathologic diagnosis.

RESULTS

The final study cohort (n = 582) was 50% black, 33% Hispanic, 12% white, 3% Asian, and 2% other; 36% had a body mass index >85%. There were 26 cases of NAFLD (4.5%) of which 10 had nonalcoholic steatohepatitis (1.7%). There were no cases with severe fibrosis or cirrhosis. One percent (3/290) of black children had NAFLD and none had nonalcoholic steatohepatitis. White and Hispanic children had the highest percentages of NAFLD at 8.3% and 7.9%, respectively. In multiple logistic regression models, we observed that body mass index z-score (P < .001) was associated with NAFLD, and that white (P = .003) and Hispanic (P = .005) children had higher odds of having NAFLD compared with black children.

CONCLUSIONS

This review of liver tissue demonstrates a lower prevalence and severity of NAFLD in black children compared with the general obese pediatric population. Hispanic children did not have a significantly increased rate of NAFLD compared with white children, most likely related to the large proportion of Caribbean Hispanic children in New York City.

Racial and Ethnic Disparities in Nonalcoholic Fatty Liver Disease Prevalence, Severity, and Outcomes in the United States: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the United States, affecting 75-100 million Americans. However, the disease burden may not be equally distributed among races or ethnicities. We conducted a systematic review and meta-analysis to characterize racial and ethnic disparities in NAFLD prevalence, severity, and prognosis.

METHODS

We searched MEDLINE, EMBASE, and Cochrane databases through August 2016 for studies that reported NAFLD prevalence in population-based or high-risk cohorts, NAFLD severity including presence of nonalcoholic steatohepatitis (NASH) and significant fibrosis, and NAFLD prognosis including development of cirrhosis complications and mortality. Pooled relative risks, according to race and ethnicity, were calculated for each outcome using the DerSimonian and Laird method for a random-effects model.

RESULTS

We identified 34 studies comprising 368,569 unique patients that characterized disparities in NAFLD prevalence, severity, or prognosis. NAFLD prevalence was highest in Hispanics, intermediate in Whites, and lowest in Blacks, although differences between groups were smaller in high-risk cohorts (range 47.6%-55.5%) than population-based cohorts (range, 13.0%-22.9%). Among patients with NAFLD, risk of NASH was higher in Hispanics (relative risk, 1.09; 95% CI, 0.98-1.21) and lower in Blacks (relative risk, 0.72; 95% CI, 0.60-0.87) than Whites. However, the proportion of patients with significant fibrosis did not significantly differ among racial or ethnic groups. Data were limited and discordant on racial or ethnic disparities in outcomes of patients with NAFLD.

CONCLUSIONS

In a systematic review and meta-analysis, we found significant racial and ethnic disparities in NAFLD prevalence and severity in the United States, with the highest burden in Hispanics and lowest burden in Blacks. However, data are discordant on racial or ethnic differences in outcomes of patients with NAFLD.

Association between PNPLA3 (rs738409 C>G) variant and hepatocellular carcinoma in Asian chronic hepatitis C patients: A longitudinal study

BACKGROUND/PURPOSE

Prdevious meta-analyses assess whether or not patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409 C > G) was associated with increased risk of hepatocellular carcinoma (HCC) in Caucasians patients with hepatitis C virus (HCV)-related cirrhosis, these meta-analyses did not provide firm conclusions. Only one cross-sectional study involving Asian patients has previously been conducted to explore this issue. We aim to investigate this in a longitudinal cohort of Asian chronic hepatitis C (CHC) patients.

METHODS

We consecutively enrolled 1011 CHC patients who underwent liver biopsy before initiating interferon-based therapy. These patients were followed-up and screened for HCC up to a median of 6.9 years. The influence of rs738409 (GG) genotype on the occurrence of HCC was assessed using the Kaplan-Meier method, then according to the multivariate Cox model.

RESULTS

During follow-up, 143 (14.1%) patients developed HCC. rs738409 (GG) genotype was not associated with time-to-HCC development on multivariate Cox regression (P = 0.634). When considering the occurrence of these events over time, rs738409 (GG) genotype did not influence the risk of HCC development (log-rank = 0.12). Among 261 patients with liver cirrhosis, rs738409 (GG) genotype was not associated with time-to-HCC development on multivariate Cox regression (P = 0.737). When considering the occurrence of these events over time, rs738409 (GG) genotype did not influence the risk of HCC development (log-rank = 0.72).

CONCLUSION

In this longitudinal study with liver biopsy to stage liver fibrosis, we affirm there is no influence of the rs738409 (GG) genotype on the occurrence of HCC in Asian CHC patients, including cirrhotic patients.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genome-wide analysis of hepatic lipid content in extreme obesity

AIMS

Individuals with type 2 diabetes have an increased risk of developing non-alcoholic fatty liver disease (NAFLD), and NAFLD patients are also at greater risk for developing type 2 diabetes. Although the relationship between type 2 diabetes and NAFLD is highly interconnected, the pathogenic mechanisms linking the two diseases are poorly understood. The goal of this study was to identify genetic determinants of hepatic lipid accumulation through association analysis using histological phenotypes in obese individuals.

METHODS

Using the Illumina HumanOmniExpress BeadChip assay, we genotyped 2,300 individuals on whom liver biopsy data were available.

RESULTS

We analyzed total bilirubin levels, which are linked to fatty liver in severe obesity, and observed the strongest evidence for association with rs4148325 in UGT1A (P < 5.0 × 10(-93)), replicating previous findings. We assessed hepatic fat level and found strong evidence for association with rs4823173, rs2896019, and rs2281135, all located in PNPLA3 and rs10401969 in SUGP1. Analysis of liver transcript levels of 20 genes residing at the SUGP1/NCAN locus identified a 1.6-fold change in the expression of the LPAR2 gene in fatty liver. We also observed suggestive evidence for association between low-grade fat accumulation and rs10859525 and rs1294908, located upstream from SOCS2 and RAMP3, respectively. SOCS2 was differentially expressed between fatty and normal liver.

CONCLUSIONS

These results replicate findings for several hepatic phenotypes in the setting of extreme obesity and implicate new loci that may play a role in the pathophysiology of hepatic lipid accumulation.

Recent advances in the herbal treatment of non-alcoholic Fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver injury across the world. It is also strongly related to other pathological conditions, including obesity, diabetes, cardiovascular diseases, and symptoms of metabolic syndrome. Pathogenesis of NAFLD remains not fully characterized but is generally attributed to the occurrence of insulin resistance, lipid metabolism dysfunction,0 oxidative stress, inflammation, and necro-apoptosis. Every potential therapeutic strategy should target one or some of these pathological events in the liver. Over the past decades, application of herbal treatment for NAFLD has received increasing attention due to its wide availability, low side effects, and proven therapeutic mechanisms and benefits. In recent years, some monomers and certain functional mixtures of herbs have been extensively examined for their potential uses in NAFLD treatment. In the present review, we selected several herbal derivatives under intense basic and/or clinical investigations by carrying out a PubMed search of English language articles relevant to herbal derivatives and NAFLD, such as polysaccharide portion of wolfberry, garlic-derived monomers, red grape-derived resveratrol, and milk thistle-derived substances. They have been shown to target the pathological events during NAFLD initiation and progression both in pre-clinical studies and clinical trials. Although more detailed mechanistic researches and long-term clinical evaluations are needed for their future applications, they offer unanticipated and great health benefits without obvious adverse effects in NAFLD therapy.

Race and the insulin resistance syndrome

Type 2 diabetes remains an important cause of morbidity and mortality. The metabolic syndrome affects 25% of the adult US population based on the Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults from the National Cholesterol Education Program. Knowledge on the impact of obesity on metabolic health parameters has increased greatly over the past decade. This review discusses the limitations of the National Cholesterol Education Program metabolic syndrome definition and the racial disparities in the clinical presentation of the insulin resistance syndrome. We also examine the current literature with particular emphasis on albuminuria, nonalcoholic fatty liver disease, and intramyocellular lipid content. This review explores potential environmental and genetic reasons for differences in the manifestation of insulin resistance across racial/ethnic groups and highlights several promising areas for further study.

Ethnic and sex differences in fatty liver on cardiac computed tomography: the multi-ethnic study of atherosclerosis

OBJECTIVE

To describe ethnic and sex differences in the prevalence and determinants of fatty liver in a multiethnic cohort.

PATIENTS AND METHODS

We studied participants of the Multi-Ethnic Study of Atherosclerosis who underwent baseline noncontrast cardiac computed tomography between July 17, 2000, and August 29, 2002, and had adequate hepatic and splenic imaging for fatty liver determination (n=4088). Fatty liver was defined as a liver/spleen attenuation ratio of less than 1. We compared the prevalence and severity of fatty liver, in 4 ethnicities (white, Asian, African American, and Hispanic), and the factors associated with fatty liver in each ethnicity, stratifying by obesity and metabolic syndrome. Multivariable ordinal logistic regression was used to determine the effect of cardiometabolic risk factors on the prevalence of fatty liver in different ethnicities.

RESULTS

The prevalence of fatty liver varied significantly by ethnicity (African American, 11%; white, 15%; Asian, 20%; and Hispanic, 27%; P<.001). Although African Americans had the highest prevalence of obesity, a smaller percentage of obese African Americans received a diagnosis of fatty liver than did other ethnicities (African American, 17%; white, 31%; Asian, 37%; and Hispanic 39%; P<.001). Hispanics had the highest prevalence of fatty liver, including the obese and metabolic syndrome population. An increase in insulin resistance predicted a 2-fold increased prevalence of fatty liver in all ethnicities after multivariable adjustment.

CONCLUSION

African Americans have a lower prevalence and Hispanics have a higher prevalence of fatty liver than do other ethnicities. There are distinct ethnic variations in the prevalence of fatty liver even in patients with the metabolic syndrome or obesity, suggesting that genetic factors may play a substantial role in the phenotypic expression of fatty liver.

Obesity-associated nonalcoholic fatty liver disease

Obesity is strongly associated with the prevalence of nonalcoholic fatty liver disease (NAFLD) in adult and pediatric populations. Nutrition, physical activity, and behavioral modifications are critical components of the treatment regimen for all obese patients with NAFLD. Bariatric surgeries that affect or restrict the flow of food through the gastrointestinal tract may improve liver histology in morbidly obese patients with nonalcoholic steatohepatitis (NASH), although randomized clinical trials and quasi-randomized clinical studies are lacking. Early detection of NASH and hepatic fibrosis using noninvasive biochemical and imaging markers that may replace liver biopsy is the current challenge.

Racial differences in nonalcoholic fatty liver disease in the U.S. population

OBJECTIVE

To characterize the prevalence of nonalcoholic fatty liver disease (NAFLD) by race in a nationally representative sample of the U.S. population and to investigate potential explanatory factors for racial disparities.

DESIGN AND METHODS

Cross-sectional study of 4,037 non-Hispanic white, 2,746 non-Hispanic black, and 2,892 Mexican-American adults in the Third National Health and Nutrition Examination Survey. NAFLD was defined using ultrasound and with elevated aminotransferases.

RESULTS

Age-adjusted prevalence of NAFLD was highest in Mexican-Americans (21.2%), followed by non-Hispanic whites (12.5%), and was lowest in non-Hispanic blacks (11.6%). Even after adjustment for demographic, lifestyle, adiposity, and metabolic factors, compared to non-Hispanic whites, Mexican-Americans were more likely to have NAFLD (OR: 1.67, 95% CI: 1.26, 2.22). Non-Hispanic blacks were significantly less likely to have NAFLD with elevated aminotransferases (OR: 0.51, 95% CI: 0.27, 0.97). Racial differences were attenuated among those with normal BMI and among "never drinkers."

CONCLUSION

In this representative sample of the U.S. population, we found significant racial differences in the prevalence of ultrasound-defined NAFLD (with and without elevated liver enzymes). The racial differences were not fully explained by lifestyle, adiposity, and metabolic factors. More works is needed to identify potential contributors.

Predictive value of ALT levels for non-alcoholic steatohepatitis (NASH) and advanced fibrosis in non-alcoholic fatty liver disease (NAFLD)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) patients with elevated serum alanine aminotransferase (ALT) generally undergo a liver biopsy to evaluate for possible non-alcoholic steatohepatitis (NASH) or advanced fibrosis. However, patients with normal ALT could also have advanced stages of NAFLD.

AIM

To determine ALT value that will accurately predict NASH and advanced fibrosis using area under the receiver operating characteristics curve (AUROC) analysis.

METHODS

Demographic, clinical and laboratory data of an ethnically diverse cohort of biopsy proven NAFLD patients were retrospectively analysed under univariate and multivariate analyses. Liver biopsies were scored using NASH clinical research network (NASH CRN) system. AUROC were performed for NAFLD Activity Score ≥5 (NASH) and fibrosis score ≥2 (advanced fibrosis).

RESULTS

Two hundred and twenty-two patients were analysed. Fifty six (23%) had normal ALT. There was no difference in the rate of advanced fibrosis between normal and elevated ALT (26.8% vs. 18.1%, P = 0.19). However, significantly lower percentage of normal ALT group had NASH compared with elevated ALT group (10.7% vs. 28.9%, P < 0.01). Overall, 37.5% of normal ALT group had NASH or advanced fibrosis, whereas 53% of elevated ALT had no NASH or advanced fibrosis. Higher ALT values correlated with higher specificity, but lower sensitivity for both NASH and advanced fibrosis. AUROC for ALT level correlating NASH and advanced fibrosis were 0.62 and 0.46 respectively.

CONCLUSION

There is no optimal ALT level to predict NASH and advanced fibrosis. Metabolic risk factors should be evaluated to select patients for a liver biopsy to confirm NASH and advanced fibrosis.

Oral contraceptive pill use is associated with reduced odds of nonalcoholic fatty liver disease in menstruating women: results from NHANES III

BACKGROUND

Higher prevalence of nonalcoholic fatty liver disease (NAFLD) in men and postmenopausal women than in premenopausal women has suggested a potential role of sex hormones in the pathogenesis of the disease. We sought to evaluate the association between oral contraceptive pills (OCP) and NAFLD and to determine whether adiposity mediates any effect.

METHODS

We included 4338 women aged 20-60 years who were enrolled in the Third National Health and Nutrition Examination Survey from 1988 to 1994 in a population-based cross-sectional study. We defined NAFLD as moderate-severe steatosis on ultrasonography in women without excessive alcohol use or other identifiable causes. OCP use was based on self-report and was categorized as never, former or current use.

RESULTS

The overall weighted prevalence of NAFLD was 11.6 % but lower in current (6.7 %) than in former (12.0 %) or never users (15.6 %, P = 0.016). In the multivariable model, current OCP users experienced a 50 % lower odds of NAFLD than never users (adjusted odds ratio 0.50; 95 % confidence interval 0.26, 0.98) after adjusting for age, race/ethnicity, smoking status, history of diabetes or hypertension and education. Further adjustment for body mass index or waist circumference significantly attenuated the OCP-NAFLD relationship.

CONCLUSIONS

In this large US-representative population, OCP use was associated with reduced odds of NAFLD. However, this association could be mediated or confounded by adiposity. Prospective studies are needed to further clarify the causal role of sex hormone.

Ethnic differences in the link between insulin resistance and elevated ALT

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) exhibits tight links with insulin resistance (IR) and the metabolic syndrome (MetS), a cluster of cardiovascular risk factors. Compared with non-Hispanic whites, non-Hispanic black adolescents have more IR but a lower prevalence of NAFLD and MetS. Our hypothesis was that IR would be a better predictor of alanine aminotransferase (ALT) elevations than is MetS among non-Hispanic blacks.

METHODS

We analyzed data from 4124 adolescents aged 12 to 19 years in the 1999 to 2010 NHANES, using unexplained elevations in ALT (>30 U/L) to characterize presumed NAFLD and using a pediatric adaptation of the Adult Treatment Panel III definition of MetS.

RESULTS

Prevalence of elevated ALT varied by race/ethnicity (Hispanics 13.7%, non-Hispanic white 8.6%, non-Hispanic blacks 5.4%, P < .0001). Among non-Hispanic whites and Hispanics, a classification of MetS performed well in identifying adolescents with elevated ALT (odds ratios [ORs] 9.53 and 5.56, respectively), as did MetS-related indices. However, among non-Hispanic blacks, the association between MetS and ALT elevations was smaller in magnitude and technically nonsignificant (OR = 3.24, P = .051). Furthermore, among non-Hispanic blacks, the presence of IR and elevated waist circumference performed more poorly at identifying ALT elevations (ORs 3.93 and 2.28, respectively: significantly smaller than ORs for non-Hispanic whites, P < .05), with triglyceride elevations being a better predictor (OR = 4.44).

CONCLUSIONS

Non-Hispanic black adolescents exhibit a lower relationship between IR and elevated ALT, supporting racial/ethnic differences in the link between MetS and NAFLD. These data may have implications regarding triggers for screening for NAFLD among non-Hispanic black adolescents, focusing particularly on those with triglyceride elevations.

Non-Alcoholic Fatty Liver Disease: Current Perspectives and Future Direction in Disease pathogenesis, Treatment and Diagnosis

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in the world. An important implication of this disease is the progression of the disease to a more complicated condition called non-alcoholic steatohepatitis (NASH) and the wide variety of clinical presentations. Over the past 5 years, remarkable progresses have been made in understanding the genetic basis for the disease. Recent clinical trials in pharmacotherapy for the disease have been encouraging as well. It is anticipated that the integration of the wide spectrum information retrieved from genomics, transcriptomics and proteomics studies conducted in NAFLD and NASH will mediate a better understanding of the disease pathogenesis and facilitate the postulation of disease pathobiology pathways. Genetic and biological markers identified from the omics studies may hold promise for diagnosis, personalized treatment, early prevention and new drug development.

Metabolic syndrome and risk factors for non-alcoholic fatty liver disease

CONTEXT: Non-alcoholic fatty liver disease (NAFLD), hepatic manifestation of metabolic syndrome, has been considered the most common liver disease nowadays, which is also the most frequent cause of elevated transaminases and cryptogenic cirrhosis. The greatest input of fatty acids into the liver and consequent increased beta-oxidation contribute to the formation of free radicals, release of inflammatory cytokines and varying degrees of hepatocytic aggression, whose histological expression may vary from steatosis (HS) to non-alcoholic steatohepatitis (NASH). The differentiation of these forms is required by the potential risk of progression to cirrhosis and development of hepatocellular carcinoma. OBJECTIVE: To review the literature about the major risk factors for NAFLD in the context of metabolic syndrome, focusing on underlying mechanisms and prevention. METHOD: PubMed, MEDLINE and SciELO data basis analysis was performed to identify studies describing the link between risk factors for metabolic syndrome and NAFLD. A combination of descriptors was used, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, metabolic syndrome and risk factors. At the end, 96 clinical and experimental studies, cohorts, meta-analysis and systematic reviews of great impact and scientific relevance to the topic, were selected. RESULTS: The final analysis of all these data, pointed out the central obesity, type 2 diabetes, dyslipidemia and hypertension as the best risk factors related to NAFLD. However, other factors were highlighted, such as gender differences, ethnicity, genetic factors and the role of innate immunity system. How these additional factors may be involved in the installation, progression and disease prognosis is discussed. CONCLUSION: Risk factors for NAFLD in the context of metabolic syndrome expands the prospects to 1) recognize patients with metabolic syndrome at high risk for NAFLD, 2) elucidate pathways common to other co-morbidities, 3) determine risk factors associated with a worse prognosis, 4) develop therapeutic strategies with goal of reducing risk factors, 5) apply acquired knowledge in public health policies focusing on preventive strategies.

Ethnicity and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in the United States; however, few data are available about racial and ethnic variation. We investigated relationships between ethnicity, NAFLD severity, metabolic derangements, and sociodemographic characteristics in a well-characterized cohort of adults with biopsy-proven NAFLD. Data were analyzed from 1,026 adults (≥18 years) in the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) from 2004 to 2008, for whom liver histology data were available within 6 months of enrollment. Associations between ethnicity (i.e., Latino versus non-Latino white) and NAFLD severity (i.e., NASH versus non-NASH histology and mild versus advanced fibrosis) were explored with multiple logistic regression analysis. We also investigated effect modification of ethnicity on metabolic derangements for NAFLD severity. Within the NASH CRN, 77% (N = 785) were non-Latino white and 12% (N = 118) were Latino. Sixty-one percent (N = 628) had NASH histology and 28% (N = 291) had advanced fibrosis. Latinos with NASH were younger, performed less physical activity, and had higher carbohydrate intake, compared to non-Latino whites with NASH. Gender, diabetes, hypertension, hypertriglyceridemia, aspartate aminotransferase (AST), platelets, and the homeostasis model assessment of insulin resistance (HOMA-IR) were significantly associated with NASH. Age, gender, AST, alanine aminotransferase, alkaline phosphatase, platelets, total cholesterol, hypertension, and HOMA-IR, but not ethnicity, were significantly associated with advanced fibrosis. The effect of HOMA-IR on the risk of NASH was modified by ethnicity: HOMA-IR was not a significant risk factor for NASH among Latinos (odds ratio [OR] = 0.93; 95% confidence interval [CI]: 0.85-1.02), but was significant among non-Latino whites (OR, 1.06; 95% CI: 1.01-1.11).

CONCLUSION

Metabolic risk factors and sociodemographic characteristics associated with NASH differ by ethnicity. Additional insights into NASH pathogenesis may come from further studies focused on understanding ethnic differences in this disease.

Nonalcoholic fatty liver disease of two ethnic groups in Kuwait: comparison of prevalence and risk factors

OBJECTIVES

To assess the prevalence of nonalcoholic hepatic steatosis (nonalcoholic fatty liver disease, NAFLD) and the significance of some risk factors, such as obesity and glucose metabolism impairment, for two major ethnic groups of Kuwait: Arabs and South Asians.

SUBJECTS AND METHODS

143 adults (Arab: n = 81; South Asian: n = 62) were enrolled in the study. Anthropometric measurements including body mass index (BMI), waist circumference (WC), hip circumference (HC) and waist-to-hip ratio were performed along with abdominal ultrasonography. The prevalence of liver steatosis was assessed; its relation to glucose metabolism impairment, obesity, age and gender was compared in the two ethnic groups.

RESULTS

Except for waist-to-hip ratio, the anthropometric parameters were higher in Arabs than South Asians. The respective parameters in Arabs and South Asians were: BMI: 30.9 ± 6.6 versus 27.0 ± 4.5, p < 0.001; WC: 101.5 ± 16.4 versus 94.0 ± 12.2, p = 0.002; HC: 106.6 ± 12.4 versus 99.2 ± 9.9, p < 0.001. Although Arabs were more obese, they did not exhibit a higher prevalence of steatosis (33.3 vs. 29.0%, p = 0.583). According to multivariate analysis, only gender (odds ratio 3.93, p = 0.005), glucose metabolism impairment (odds ratio 4.94, p = 0.003) and WC (odds ratio 4.75, p = 0.012) remained significantly associated with steatosis.

CONCLUSION

No significant difference in NAFLD prevalence was found between Arabs and South Asians. Only gender, history of impaired glucose metabolism and abdominal obesity expressed by WC had an independent predictive value for developing liver steatosis.

Implications of worse renal dysfunction and medical comorbidities in patients with NASH undergoing liver transplant evaluation: impact on MELD and more

Increasing numbers of patients with non-alcoholic steatohepatitis (NASH) are referred for liver transplant (LT). Our objective was to characterize patients with NASH among referred LT candidates (from 1998 to 2008), and we compared demographics, etiology of liver disease, diabetes, hypertension, smoking, obesity, cardiac disease, cancer, laboratory data, model for end-stage liver disease (MELD), and outcomes between NASH and non-NASH patients. Patients with NASH (n = 71) were compared to other chronic liver disease (n = 472). Patients with NASH were older (58.7 vs. 52.5 yr, p < 0.0001), Asian (53.5% vs. 34.7%, p = 0.03) and women (50.7% vs. 32.1%, p = 0.003). Patients with NASH had more diabetes, hypertension, obesity, cardiac disease, and smoking history (p < 0.05). Patients with NASH were equally likely to have liver cancer, but more likely to have non-liver cancers (20.8% vs. 4.4%, p = 0.008). There was no difference in MELD, but patients with NASH had lower protime/international normalized ratio (1.14 vs. 1.27, p = 0.04) and higher creatinine (1.26 vs. 0.98 mg/dL, p = 0.0018). Patients with NASH were equally likely to undergo evaluation, listing, and transplantation compared to non-NASH patients. While all patients with chronic liver disease can have renal dysfunction because of hepatorenal syndrome, patients with NASH have more renal dysfunction, perhaps related to diabetes, hypertension, and cardiovascular disease. Transplant centers should consider this carefully in selection of candidates for LT.

Lack of association of GSTT1 and GSTP1 genes methylation and their expression profiles with risk of NAFLD in a sample of Iranian patients

Reactive oxygen species can affect many cellular functions through protein oxidation or initiation of the lipid peroxidation cascade that can lead to non-alcoholic fatty liver disease (NAFLD), characterized by significant lipid deposition in the hepatocytes of patients with no history of excess alcohol intakes. The present study aimed to analyze the methylation status of the antioxidative stress genes GSTT1 (glutathione S-transferase theta-1) and GSTP1 (glutathione S-transferase pi-1), and their expression profiles, in a sample population of patients with NAFLD living in South-East Iran.

PATIENTS AND METHODS

Peripheral blood samples were obtained from 80 NAFLD patients and 80 healthy controls. Promoter methylation of the GSTT1 and GSTP1 genes were analyzed by methylation-specific polymerase chain reaction (MS-PCR). Expression profiles of these genes were also examined by quantitative real-time PCR analysis.

RESULTS

Promoter methylation of the GSTT1 gene was detected in 86.2% of cases and in 91.2% of controls and, of the GSTP1 gene, in 88.8 and 87.5% of cases and controls, respectively. Promoter methylation of GSTT1 and GSTP1 was not statistically different in cases compared with healthy controls. Similarly, mRNA expression levels showed no statistically significant variations between healthy individuals and patients with NAFLD.

CONCLUSION

Our findings indicate no association between methylation status and expression profiles of GSTT1 and GSTP1 genes and NAFLD. This is the first report to assess such associations in a sample of the Iranian population.

Inflammation in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) describes a range of disorders characterized by excess accumulation of triglyceride within the liver. While simple steatosis may be clinically stable, nonalcoholic steatohepatitis (NASH) can be progressive. Inflammation is believed to be the driving force behind NASH and the progression to fibrosis and subsequent cirrhosis. This article will review and interpret the current literature in an attempt to expand our understanding of the environmental and genetic causes of inflammation and its effects in NAFLD.

Decreased immunoexpression of survivin could be a potential marker in human non-alcoholic fatty liver disease progression?

BACKGROUND/AIM

Regulation of apoptosis in non-alcoholic fatty liver disease (NAFLD) has been a theme of growing debate. Although no other study assessed the role of survivin in NAFLD, its expression has been reported in hepatic carcinogenesis because of other aetiological factors with relevant discrepancies. The aim of this study was to assess the pattern of survivin immunoexpression by tissue microarray along the whole spectrum of NAFLD, including non-alcoholic steatohepatitis (NASH)-related hepatocellular carcinoma (HCC).

METHODS

Liver biopsies from 56 patients with NAFLD were evaluated: 18 with steatosis, 21 non-cirrhotic NASH, 10 NASH-related cirrhosis, seven NASH-related HCC, as compared with 71 HCC related to other causes and with 12 normal livers.

RESULTS

Survivin immunoexpression in NAFLD was restricted to cytoplasm and was found to be progressively lower in advanced stages, including cirrhosis and HCC: steatosis vs NASH-related cirrhosis (P=0.0243); steatosis vs NASH-related HCC (P=0.0010); NASH vs NASH-related cirrhosis (P=0.0318); and NASH vs NASH-related HCC (P=0.0007), thus suggesting a deregulation of apoptosis from NAFLD towards HCC. Interestingly, survivin immunoreactivity in NASH-related HCC was also found to be significantly lower than in HCC related to other causes (P<0.05). Remarkably, nuclear staining for survivin was not detected in any case of NAFLD, contrasting to its presence in all other cases of HCC.

CONCLUSIONS

Survivin immunoexpression in NASH-related HCC is herein originally found substantially different than in HCC related to other causes, thus requiring further studies to elucidate the role of survivin in human NAFLD progression.

Nonalcoholic fatty liver disease across ethno-racial groups: do Asian-American adults represent a new at-risk population?

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) is increasingly common worldwide. We explored clinical, laboratory, and histological features of NAFLD as well as risk factors for histologically advanced disease among under-represented ethno-racial groups.

METHODS

Patient records from one NAFLD clinic in California from 1998-2008 were reviewed. Biopsies were graded using Brunt criteria by a hepatopathologist blinded to clinical data. We used multivariate logistic regression to assess associations between ethno-racial group and histological severity of NAFLD, while controlling for other factors.

RESULTS

We identified 90 biopsy-proven cases of NAFLD. Mean age was 49 years (standard deviation [SD]= 11.6), and half were female. 52% of patients were Caucasian, 20% Latino-American, 18% Asian-American, and 10% Middle Eastern-American. There were significant differences among groups with respect to age, weight, body mass index (BMI), and grade of hepatic steatosis (all P < 0.05). In multivariate analysis, older age was associated with severe (Brunt ≥ 2) inflammation (odds ratio [OR] 1.1, P = 0.002) and severe (Brunt ≥ 3) fibrosis (OR 1.2, P = 0.001), diabetes was associated with severe inflammation (OR 3.18, P = 0.07) and severe fibrosis (OR 8.81, P = 0.002), and increased BMI was associated with severe fibrosis (OR 2.43, P = 0.07). Additionally, compared to Caucasians, Asian-Americans showed a trend toward an association with severe (Brunt > 2) steatosis (OR 3.83, P = 0.08) and severe inflammation (OR 5.42, P = 0.06).

CONCLUSIONS

The findings from this ethno-racially diverse clinic-based cohort are consistent with prior studies and also suggest that Asian-Americans may be at risk for advanced NAFLD. This may have implications for the prevention, evaluation, and treatment of patients with NAFLD that merit further study.

Nonalcoholic fatty liver disease and hepatocellular carcinoma: a weighty connection

Hepatocellular carcinoma (HCC) is a common and deadly malignancy that is increasing in incidence in developed countries. The emergence of hepatitis C virus (HCV) accounts for about half of this increase in HCC, although the etiology of HCC in 15%-50% of new HCC cases remains unclear. The most common form of chronic liver disease in developed countries is nonalcoholic fatty liver disease (NAFLD), which encompasses a broad spectrum of histopathology. The prevalence of NAFLD, including the more aggressive nonalcoholic steatohepatitis (NASH), is increasing with the growing epidemics of diabetes and obesity. NASH can progress to cirrhosis and its related complications. Growing evidence suggests that NASH accounts for a large proportion of idiopathic or cryptogenic cirrhosis, which is associated with the typical risk factors for NASH. HCC is a rare, although important complication of NAFLD. Diabetes and obesity have been established as independent risk factors for the development of HCC. New evidence also suggests that hepatic iron deposition increases the risk of HCC in NASH-derived cirrhosis. Multiple case reports and case reviews of HCC in the setting of NASH support the associations of diabetes and obesity with the risk of HCC, as well as suggest age and advanced fibrosis as significant risks. Insulin resistance and its subsequent inflammatory cascade that is associated with the development of NASH appear to play a significant role in the carcinogenesis of HCC. The complications of NASH, including cirrhosis and HCC, are expected to increase with the growing epidemic of diabetes and obesity.

Pathology of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a significant complication of obesity and is recognized as the hepatic manifestation of the metabolic syndrome. The process occurs in adults and children and is characterized by the presence of increased amounts of fat in the liver (steatosis). With inflammation, cell death and scarring (fibrosis), the process may result in end-stage liver disease, or be a precursor for hepatocellular carcinoma. Excess hepatic fat is now recognized as an independent marker for increased cardiovascular risk. Even though imaging studies and laboratory-based tests are accurate at detecting significant steatosis and/or advanced fibrosis, respectively, the diagnosis and characterization of NAFLD ultimately depend on histopathologic evaluation, as the parenchymal alterations that comprise the spectrum of injury in NAFLD include patterns as well as specific lesions. Histologic findings in children may differ from those in adults. In this Review, the histologic features that are diagnostic and discriminatory between steatosis and steatohepatitis, the significance of the distinction between steatosis and steatohepatitis, the types and locations of fibrosis, and the histologic variances between adult and pediatric NAFLD are discussed. Clinical advantages as well as potential drawbacks of liver biopsy are presented. Current pathophysiologic concepts relevant to histologic findings are discussed.

Treatment options for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become increasingly recognized as the most common cause of abnormal liver enzymes in the last few decades and is among the most common forms of chronic liver disease in the Western world and across the globe. With the growing epidemic of obesity and diabetes, NAFLD is estimated to affect about one-quarter of the US population. Although most patients with NAFLD have nonprogressive bland steatosis, a minority of patients develop the histological subtype of nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis, hepatocellular carcinoma, and liver-related death. This is especially true when NASH patients have type 2 diabetes. Treatment of NAFLD should therefore be directed towards patients with established NASH. Sustained weight loss seems to improve insulin resistance and associated NASH. In fact, weight loss with bariatric surgery leads to biochemical and histological improvement in morbidly obese patients with NASH. Several pharmacologic agents have been studied in an effort to improve insulin resistance and pro-inflammatory mediators potentially responsible for the development and progression of NASH. While some studies have shown initial promise, none has established long-term efficacy using randomized clinical trials. This paper briefly reviews the epidemiology, natural history, and pathophysiology of NAFLD and NASH and then focuses on the clinical trials of various therapeutic modalities for NAFLD. These include weight loss agents, bariatric surgery, insulin-sensitizing agents, lipid-lowering agents, antioxidants, probiotics, anti-tumor necrosis factor agents, cytoprotective and other novel agents.

Nonalcoholic fatty liver disease: a review and update

The spectrum of nonalcoholic fatty liver disease (NAFLD) ranges from asymptomatic steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Hepatic steatosis occurs when free fatty acids, released in the setting of insulin resistance and the metabolic syndrome, are taken up by the liver. Additional biochemical insults, including oxidative stress, upregulation of inflammatory mediators, and dysregulated apoptosis, can result in inflammation (producing NASH) and fibrosis. Noninvasive methods (e.g., abdominal ultrasonography) are safe ways to support a diagnosis of hepatic steatosis, but advanced liver histopathologic findings including NASH and fibrosis cannot be identified without pursuing liver biopsy. Recent advances in serologic and imaging methods aim to determine severity of inflammation and fibrosis noninvasively. Currently, therapeutic options for NAFLD are limited to medications that reduce risk factors, but the future holds promise for therapies that might slow the progression of this increasingly prevalent disorder.

Cryptogenic cirrhosis: what are we missing?

Cryptogenic cirrhosis remains a common clinical condition although recent advances have allowed for a better understanding of underlying conditions and associations. The evolving terminology applied to this condition has resulted in some confusion and persistent variation among pathologists and clinicians. Typical patients are middle aged with only minor liver enzyme abnormalities. Presentations range from incidentally discovered cirrhosis to complications of advanced portal hypertension and hepatocellular cancer. Clinicopathologic analysis of these patients indicates that the leading causes include previously unrecognized nonalcoholic steatohepatitis, silent autoimmune hepatitis, non-B, non-C viral hepatitis, and occult past ethanol exposure. In this article, we review these associations as well as a proposed classification system for cryptogenic cirrhosis and other lesser known genetic and syndromic associations that warrant consideration when evaluating these individuals.

Hepatic gene expression of Caucasian and African-American patients with obesity-related non-alcoholic fatty liver disease

BACKGROUND/AIM

There is increasing data suggesting that African Americans with NAFLD tend to have less progressive liver disease. The aim of this study is to assess differences in the hepatic gene expression of African-American and Caucasian patients with NAFLD who had undergone bariatric surgery.

METHODS

A total of 94 patients (81 NAFLD and 13 weight-matched controls with normal liver biopsy) were included. Of the entire cohort, 73 were Caucasians and 21 were African Americans. All patients were undergoing bariatric surgery. Two liver biopsies were obtained at the time of surgery. One biopsy was snap-frozen for gene expression and the other biopsy was stained for pathologic assessment. Liver biopsy confirmed that 24 patients from our cohort had NASH while 57 had only simple steatosis. Snap-frozen liver biopsy specimens of these patients were then used for the RNA extraction. cDNA probes were hybridized with customized microarray gene chips containing 5,220 relevant genes. Gene expression profiles were compared between groups using significance analysis of microarrays algorithm.

RESULTS

In comparison to all Caucasian patients, African-American patients had over-expression of EPB41L1, IGF2, FAH, ACSL4, FUT4, CYP3A (q values < 10(-4)). In comparison to Caucasian NAFLD patients, African-American NAFLD patients showed over-expression of EPB41L1 and ACSL4 genes. Finally, in comparison to Caucasian NASH patients, African-American NASH patients showed over-expression of GSTM 2, GSTM4 and GSTM5 as well as FH and ASCL4 genes. Some genes highlighted by this analysis, particularly cytochrome CYP3A and glutathione transferases GSTM2, 4, 5, were previously implicated in the pathogenesis of NASH.

CONCLUSION

African-American patients with biopsy-proven obesity-related NAFLD and NASH have a specific hepatic gene expression pattern that may explain their differences from Caucasian patients with NAFLD in developing progressive liver disease.

Genetic polymorphisms in non-alcoholic fatty liver disease: Clues to pathogenesis and disease progression

The spectrum of non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis through steatohepatitis to advanced fibrosis and cirrhosis. Although the reason why only a minority of patients develop progressive forms of disease still remains largely unclear, recent research has identified genetic factors as a possible basis for this variation in disease presentation. Most of the studies have been focused on finding associations between advanced disease forms and selected single nucleotide polymorphisms in genes encoding various proteins involved in disease pathogenesis. Although there are many limitations regarding the study design and interpretation of published data, further carefully planned studies together with implementation of new genetic technologies will likely bring new insights into disease pathogenesis and potential benefits to the management of patients with NAFLD.