Identification of novel noninvasive markers for diagnosing nonalcoholic steatohepatitis and related fibrosis by data mining

Impact of therapeutic plasma exchange on intact protein S, apolipoproteins, and thrombin generation

INTRODUCTION

Therapeutic plasma exchange (TPE), with solvent/detergent (S/D)-treated plasma as replacement fluid, is an extracorporeal blood purification technique with major impact on both coagulation and lipids. Our previous in vitro study showed that S/D-plasma enhances thrombin generation by lowering intact protein S (PS) levels.

AIMS

To evaluate the impact of altered lipid balance on coagulation phenotype during heparin-anticoagulated TPE with S/D-plasma, and to investigate whether the lowered intact PS levels with concomitant procoagulant phenotype, are recapitulated in vivo.

METHODS

Coagulation biomarkers, thrombin generation with Calibrated Automated Thrombogram (CAT), and lipid levels were measured before and after the consecutive 1st, 3rd and 5th episodes of TPE performed to six patients with Guillain-Barré syndrome or myasthenia gravis. The effects of in vitro dilution of S/D-plasma on thrombin generation were explored with CAT to mimic TPE.

RESULTS

Patients did not have coagulation disorders, except elevated FVIII. Intact PS, lipoproteins, especially LDL, Apolipoprotein CIII (ApoC3) and ApoB/ApoA1 ratio declined (p < 0.05). In contrast, VLDL and triglyceride levels stayed intact. CAT lag time shortened (p < 0.05). In vitro dilution of S/D plasma with co-transfused Ringer's lactate and 4% albumin partially reduced its procoagulant phenotype in CAT, which is mainly seen as peak thrombin, and modestly shortened lag time.

CONCLUSIONS

After the five settings of TPE using S/D-plasma in vivo, which associated with heparinization and reduced coagulation factor activities, our observations of declining natural anticoagulant intact PS and apolipoproteins refer to rebalance of the hemostatic and lipid profiles.

Impact of fibrosis on liver-related event incidence in nonalcoholic fatty liver disease: A multicenter observational study

AIM

There are few reports on the prognosis of liver-related events in Japanese patients with nonalcoholic fatty liver disease (NAFLD). We undertook an observational study to compare the prognosis between fibrotic and nonfibrotic groups in Japanese NAFLD patients.

METHODS

Prognosis in 393 NAFLD patients who underwent liver biopsy between April 2013 and April 2015 at multiple centers were investigated. The time to onset of liver-related events, cardiovascular events, development of extrahepatic cancers, and death were compared between the pathologically fibrotic nonalcoholic steatohepatitis (NASH) group and nonalcoholic fatty liver (NAFL) + nonfibrotic NASH group. A similar analysis was carried out based on the fibrotic classification diagnosed using four noninvasive fibrosis prediction models.

RESULTS

The mean age and body mass index at the time of liver biopsy was 55.7 years old and 28.04 kg/m2 , respectively The cumulative incidence of liver-related events at 1080 days after liver biopsy was 5.79% in the pathologically fibrotic NASH group and 0% in the NAFL + nonfibrotic NASH group, with a significant difference (p = 0.0334). The cumulative incidence of liver-related events was significantly higher in the positive group for the prediction model than in the negative group in all four models (all p values were <0.0001). There was no significant difference between the pathologically fibrotic NASH group and NAFL + nonfibrotic NASH group in terms of cumulative incidence of cardiovascular events, development of extrahepatic cancers, and death.

CONCLUSIONS

The incidence of liver-related events was significantly higher in the fibrotic NASH group than that of the NAFL + nonfibrotic NASH group in Japanese NAFLD patients.

Noninvasive biochemical markers and surrogate scores in evaluating nonalcoholic steatohepatitis

The histological features of nonalcoholic steatohepatitis (NASH) are the presence of hepatic steatosis with concomitant inflammation, ballooned hepatocytes, and potential fibrosis, which can lead to liver cirrhosis. To reduce the need for liver biopsy, that is still the gold standard for diagnosing NASH, various noninvasive biomarkers have been investigated. This narrative review summarizes the current knowledge about noninvasive diagnostic biomarkers and scores proposed for patients with NASH. A search was performed in the main medical literature databases. The following search terms were used: NASH, noninvasive biomarkers or NASH scores and panels. We focused only on studies assessing NASH diagnosis or predictive values for biomarkers, panels and scores. Data on their accuracy in predicting NASH were collected. Several panels such as NAFLD Fibrosis Score (NFS), Fibrosis-4 (FIB-4), and FibroMeter presented good predictive values of NASH, with novel proteomics panels such as the NAFLD Fibrosis Protein Panel (NFPP) using mainly the adisintegrin and metalloproteinase with thrombospondin motifs like 2 (ADAMTSL2) that showed an advantage in predicting NASH compared to NFS and FIB-4. Another novel panel, Index of NASH (ION) performed better than cytokeratin 18 (CK-18) in excluding severe fibrosis, but the overall accuracy of ION and CK-18 was modest compared to NFS and FIB-4 as it did not provide any significant advantage. Noninvasive biomarkers are currently unable to replace liver biopsy and histological assessment. However, they may play a key and vital role in triaging patients for liver biopsy, lowering the related financial burden. Future studies are needed to verify the predictive values of the newly emerging tests and panels as well as to find more affordable and reliable noninvasive early diagnostic tools.

MCAD activation by empagliflozin promotes fatty acid oxidation and reduces lipid deposition in NASH

Medium-chain acyl-CoA dehydrogenase (MCAD) is one of the significant enzymes involved in the β-oxidation of mitochondrial fatty acids. MCAD deficiency affects the β-oxidation of fatty acid and leads to lipid deposition in multiple organs, but little is known about its importance in nonalcoholic steatohepatitis (NASH). Empagliflozin is revealed to effectively improve NASH by increasing research, whereas the specific mechanism still has to be explored. Human liver tissues of patients with or without NASH were obtained for proteomic analysis to screen proteins of interest. db/db mice were given empagliflozin by gavage for 8 weeks. The expression of MCAD and signaling molecules involved in hepatic lipid metabolism was evaluated in human liver, mice and HL7702 cells. We found that the MCAD levels in the liver were significantly reduced in NASH patients compared to patients without NASH. Protein-protein interaction network analysis showed that MCAD was highly correlated with forkhead box A2 (FOXA2) and protein kinase AMP-activated catalytic subunit alpha (PRKAA). AMPK/FOXA2/MCAD signaling pathway was detected to be inhibited in the liver of NASH patients. Decreased expression of MCAD was also observed in the livers of db/db mice and hepatocyte treated with palmitic acid and glucose. Of note, empagliflozin could upregulate MCAD expression by activating AMPK/FOXA2 signaling pathway, reduce lipid deposition and improve NASH in vivo and in vitro. This research demonstrated that MCAD is a key player of hepatic lipid deposition and its targeting partially corrects NASH. MCAD thus may be a potential therapeutic target for the treatment of NASH.

Comparison of thrombocytopenia between patients with non-alcoholic fatty liver disease and those with hepatitis C virus-related chronic liver disease

AIM

Thrombocytopenia is widely recognized as a simple surrogate marker of liver fibrosis in non-alcoholic fatty liver disease (NAFLD). Thrombocytopenia of NAFLD has not been compared with that of hepatitis C virus-related chronic liver disease (CLD-C). Here, we examined whether there is any difference in the platelet counts between patients with NAFLD and CLD-C and investigated the underlying mechanisms.

METHODS

A total of 760 biopsy-confirmed NAFLD and 1171 CLD-C patients were enrolled. After stratification according to the liver fibrosis stage, platelet counts between NAFLD and CLD-C patients were compared. The platelet count, spleen size, serum albumin level, serum thrombopoietin level, and immature platelet fraction (IPF) value were also compared after covariate adjustment using propensity score (PS) matching.

RESULTS

The median platelet counts (×10⁴ /μL) of NAFLD and CLD-C patients were 20.2 and 18.7 (p = 2.4 × 10^-5 ) in F1; 20.0 and 14.5 (p = 2.1 × 10^-12 ) in F2; 16.9 and 12.3 (p = 8.1 × 10^-10 ) in F3; and 11.1 and 8.1 (p = 0.02) in F4, respectively. In the F3 group, NAFLD patients had a significantly higher platelet count and significantly smaller spleen volume than CLD-C patients. Although the serum thrombopoietin levels were comparable between NAFLD and CLD-C patients, the IPF value of NAFLD patients was significantly higher than that of CLD-C patients.

CONCLUSIONS

NAFLD patients had a significantly higher platelet count than CLD-C patients following stratification according to the liver fibrosis stage. The milder hypersplenism and higher platelet production in NAFLD than CLD-C may have contributed to this difference.

Investigating the growth performance, meat quality, immune function and proteomic profiles of plasmal exosomes in Lactobacillus plantarum-treated broilers with immunological stress

Exosomes are extracellular membranous nanovesicles that carry functional molecules to mediate cell-to-cell communication. To date, whether probiotics improve the immune function of broilers by plasmal exosome cargo is unclear. In this study, 300 broilers were allocated to three treatments: control diet (CON group), control diet + dexamethasone injection (DEX group), and control diet containing 1 × 10⁸ cfu g^-1 P8 + DEX injection (P8 + DEX group). The growth performance, meat quality and immune function of plasma and jejunal mucosa were detected. Exosomes were isolated from the plasma and characterized. Then, the exosome protein profile was determined by proteomic analysis. Correlation analyses between the exosomal proteins and growth performance, meat quality, immune function were performed. Lastly, the related protein levels were verified by multiple reaction monitoring (MRM). Results showed that P8 treatment increased the growth performance, meat quality and immune function of DEX-induced broilers with immunological stress. Moreover, the average diameters, cup-shaped morphology and expressed exosomal proteins confirmed that the isolated extracellular vesicles were exosomes. A total of 784 proteins were identified in the exosomes; among which, 126 differentially expressed proteins (DEPs) were found between the DEX and CON groups and 102 DEPs were found between the P8 + DEX and DEX groups. Gene ontology analysis indicated that DEPs between the DEX and CON groups are mainly involved in the metabolic process, cellular anatomical entity, cytoplasm, etc. DEPs between the P8 + DEX and DEX groups are mainly involved in the multicellular organismal process, response to stimulus, cytoplasm, etc. Pathway analysis revealed that most of the DEPs between the DEX and CON groups participated in the ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton, etc. Most of the DEPs between the P8 + DEX and DEX groups participated in the ErbB and PPAR signaling pathways. Moreover, many DEPs were correlated with the altered parameters of growth performance, meat quality and immunity in P8-treated broilers. MRM further revealed that the upregulated FABP6 and EPCAM in the DEX group were decreased by P8 + DEX treatment, and the downregulated C1QTNF3 in the DEX group was increased by P8 + DEX treatment. In conclusion, our findings demonstrated that P8 may promote the immune function, growth performance and meat quality of broilers with immunological stress by regulating the plasma exosomal proteins, especially the proteins of FABP6, EPCAM and C1QTNF3 and the pathway of PPAR (ILK/FABP6).

Network pharmacology-based identification of significant pathway for protection of Yinhuang granule in a mice model of metabolic-associated fatty liver disease

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) is a spectrum of liver disorders. Nonalcoholic steatohepatitis (NASH) is defined as a more serious process of MAFLD with liver inflammation.

PURPOSE

This study aims to observe the alleviation of Yinhuang granule (YHG), a Chinese patent medicine, on methionine and choline-deficient diet (MCD)-induced MAFLD in mice.

METHODS

Network pharmacology was used to analyze the improving effect of YHG on MAFLD and possible targets. MAFLD was induced in mice by MCD diet feeding for 6 weeks. In the last 2 weeks, the mice were orally given with YHG (400, 800 mg/kg) every day. Biochemical parameters of serum and liver, as well as hepatic gene expression were detected.

RESULTS

Network pharmacology showed that YHG could improve MAFLD, inflammation, liver fibrosis, and oxidative stress. In animal experiments, YHG reduced hepatocellular damage and hepatic lipids accumulation which induced by MCD. In terms of liver inflammation, YHG attenuated MCD-induced liver inflammation in mice. YHG also inhibited the activation of hepatic stellate cells (HSCs) and alleviated liver fibrosis in MCD-fed mice. Through nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, YHG alleviated liver oxidative stress injury in mice which induced by MCD.

CONCLUSION

YHG ameliorated MCD-induced MAFLD in mice by reducing hepatic lipids accumulation, alleviating liver oxidative, inflammatory injury and attenuating hepatic fibrosis.

Novel artificial intelligent/neural network system for staging of nonalcoholic steatohepatitis

AIM

To develop a novel noninvasive test using an artificial intelligence (AI)/neural network (NN) system (named Fibro-Scope) to determine the fibrosis stage in nonalcoholic steatohepatitis (NASH).

METHODS

Three hundred twenty-four and 110 patients with histologically diagnosed nonalcoholic fatty liver disease (NAFLD) were enrolled for training and validation studies, respectively. Two independent pathologists histologically diagnosed patients with NAFLD for the validation study. Fibro-Scope was undertaken using 12 items: age, sex, height, weight, waist circumference, aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, cholesterol, triglyceride, platelet count, and type 4 collagen 7s.

RESULTS

Differentiation of F0 versus F1-4 using the Fibro-Scope revealed 99.5% sensitivity, 90.9% specificity, 97.4% positive predictive value, and 98.0% negative predictive value in a training study with gray zone analysis, which was also effective in the analysis without gray zone. Discrimination was also excellent when comparing F0-1 versus F2-4 and F0-2 versus F3-4. In a validation study with gray zone analysis, differentiation of F0 from F1-4 using Fibro-Scope was also excellent. The discrimination of F0-1 from F2-4 using Fibro-Scope with gray zone analysis showed over 80% sensitivity and specificity in the histological diagnosis of both pathologists, but was lower without the gray zone analysis. The discrimination of F0-2 from F3-4 was effective in the analysis with gray zone; however, their sensitivity and specificity were slightly inferior in the analysis without gray zone.

CONCLUSIONS

Artificial intelligence/neural network algorithms termed Fibro-Scope are easy to use and can accurately differentially diagnose minimal, moderate, and advanced fibrosis. Fibro-Scope will promote rapid NASH diagnosis and facilitate diagnosing the fibrosis stage in NASH.

Artificial intelligence/neural network system for the screening of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

AIM

We aimed to develop a novel noninvasive test using an artificial intelligence (AI)/neural network (NN) system (named nonalcoholic steatohepatitis [NASH]-Scope) to screen nonalcoholic fatty liver disease (NAFLD) and NASH.

METHODS

We enrolled 324 and 74 patients histologically diagnosed with NAFLD for training and validation studies, respectively. Two independent pathologists histologically diagnosed patients with NAFLD for validation study. Additionally, 48 subjects who underwent a medical health checkup and did not show fatty liver ultrasonographically and had normal serum aminotransferase levels were categorized as the non-NAFLD group. NASH-Scope was based on 11 clinical values: age, sex, height, weight, waist circumference, aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, cholesterol, triglyceride, and platelet count.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operator characteristic curve of NASH-Scope for distinguishing NAFLD from non-NAFLD in the training study and validation study were 99.7% versus 97.2%, 97.8% versus 97.8%, 99.7% versus 98.6%, 97.8% versus 95.7%, and 0.999 versus 0.950, respectively. Those for distinguishing NASH with fibrosis from NAFLD without fibrosis were 99.5% versus 90.7%, 84.3% versus 93.3%, 94.2% versus 98.0%, 98.6% versus 73.7%, and 0.960 versus 0.950. These results were excellent, even when the output data were divided into two categories without any gray zone.

CONCLUSIONS

The AI/NN system, termed as NASH-Scope, is practical and can accurately differentially diagnose between NAFLD and non-NAFLD and between NAFLD without fibrosis and NASH with fibrosis. Thus, NASH-Scope is useful for screening nonalcoholic fatty liver and NASH.

A novel rapid immunoassay of serum type IV collagen 7S for the diagnosis of fibrosis stage of nonalcoholic fatty liver diseases

AIM

Type IV collagen 7S (T4C7S) is a valuable biomarker for detecting liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). The conventional T4C7S measurement via radioimmunoassay (T4C7S RIA) has shortcomings of radioisotope usage and longer assay periods. We compared T4C7S RIA with a newly developed, fast T4C7S chemiluminescent enzyme immunoassay (T4C7S CLEIA) and examined the diagnostic accuracies of and correlation between the two techniques.

METHODS

We evaluated 170 biopsy-confirmed patients with NAFLD. T4C7S was measured via both T4C7S RIA and T4C7S CLEIA. The correlation between T4C7S RIA and T4C7S CLEIA was analyzed in 305 total serum samples via exploratory research and 47 validation samples. The diagnostic accuracies of T4C7S CLEIA and T4C7S RIA were compared in the sera of patients with NAFLD and test samples.

RESULTS

Sera T4C7S levels of T4C7S CLEIA and T4C7S RIA significantly correlated in patients' samples via exploratory (r = 0.914, P = 0.000) and validation (r = 0.929, P = 0.000) research. At a 10% coefficient, T4C7S CLEIA concentration was 0.26 ng/ml in the serum samples, indicating high accuracy at even low concentrations. T4C7S CLEIA revealed distinct changes between each stage and high sensitivity in detecting the F2 stage, indicating a higher sensitivity in detecting low fibrosis stages than T4C7S RIA in patients with NAFLD.

CONCLUSIONS

The T4C7S CLEIA correlated well with the T4C7S RIA. Favorably, the T4C7S CLEIA has a higher sensitivity and rapid measurement time and requires a small sample volume; thus, it is a promising and popular biomarker for fibrosis stage diagnosis in NAFLD.

Epidemiology: Pathogenesis, and Diagnostic Strategy of Diabetic Liver Disease in Japan

Type 2 diabetes (T2D) is closely associated with nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH), a severe form of NAFLD, can lead to cirrhosis, hepatocellular carcinoma (HCC), and hepatic decompensation. Patients with T2D have twice the risk of HCC incidence compared with those without T2D. Because the hepatic fibrosis grade is the main determinant of mortality in patients with NAFLD, identifying patients with advanced fibrosis using non-invasive tests (NITs) or imaging modalities is crucial. Globally, the fibrosis-4 index (FIB-4 index), NAFLD fibrosis score, and enhanced liver fibrosis test have been established to evaluate hepatic fibrosis. Two-step algorithms using FIB-4 index as first triaging tool are globally accepted. It remains unknown which kinds of NITs or elastography are best as the second step tool. In Japan, type IV collagen 7s or the CA-fibrosis index (comprising type IV collagen 7s and aspartate aminotransferase (AST)) is believed to precisely predict advanced fibrosis in NAFLD. Patients with NAFLD who have high non-invasive test results should be screened for HCC or esophageal varices. Risk factors of rapid fibrosis progression in NAFLD includes age, severe obesity, presence of T2D, menopause in women, and a patatin-like phospholipase domain containing the 3 GG genotype. Patients with NAFLD who have these risk factors should be intensively treated with lifestyle modification or pharmacotherapies for preventing liver-related mortality.

Diagnostic accuracy of combined biomarker measurements and vibration-controlled transient elastography (VCTE) for predicting fibrosis stage of non-alcoholic fatty liver disease

BACKGROUND

Numerous biomarkers have been developed for assessing the presence and severity of liver fibrosis associated with non-alcoholic fatty liver disease (NAFLD). Fibrosis can be assessed by liver stiffness measurement (LSM) using vibration-controlled transient elastography (VCTE). Here we examined whether diagnostic accuracy and applicability can be further improved by combining various biomarker measurements with LSM.

METHODS

A total of 278 patients with biopsy-confirmed Japanese NAFLD patients were enrolled. Area under the receiver operator characteristic curve (AUROC) was evaluated for obtaining the optimum interpretation criteria for LSM by VCTE and comparing various biomarkers alone and in combination with LSM.

RESULTS

Liver stiffness measurements including cases with interquartile range (IQR)/median (M) < 30% or LSM ≤ 7.1 kPa demonstrated high applicability (90% of patients with NAFLD) and accuracy (AUROC: 0.891) for predicting stage ≥ 3 fibrosis. For all biomarkers tested, the AUROC values for predicting stage ≥ 3 fibrosis were increased when combined with LSM [platelet count, 0.734 vs. 0.912; type-4 collagen 7s (T4C7s), 0.894 vs. 0.921; aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT), 0.774 vs. 0.906; AST to platelet ratio index, 0.789 vs. 0.902; FIB-4 index, 0.828 vs. 0.922; NAFLD fibrosis score, 0.800 vs. 0.906; CA index-fibrosis, 0.884 vs. 0.913; FM-fibro index, 0.920 vs. 0.943; FIB-4 index + T4C7s, 0.901 vs. 0.930], demonstrating the advantage of concurrent LSM.

CONCLUSIONS

While VCTE has slightly limited applicability (90%) for patients with NAFLD, concurrent measurement with certain biomarkers (especially FM-fibro, T4C7s, and FIB-4) greatly improves the diagnostic accuracy.

Noninvasive Tests Accurately Identify Advanced Fibrosis due to NASH: Baseline Data From the STELLAR Trials

Accurate noninvasive tests (NITs) are needed to replace liver biopsy for identifying advanced fibrosis caused by nonalcoholic steatohepatitis (NASH). We analyzed screening data from two phase 3 trials of selonsertib to assess the ability of NITs to discriminate advanced fibrosis. Centrally read biopsies from the STELLAR studies, which enrolled patients with bridging fibrosis and compensated cirrhosis, were staged according to the NASH Clinical Research Network classification. We explored associations between fibrosis stage and NITs, including the nonalcoholic fatty liver disease fibrosis score (NFS), fibrosis-4 (FIB-4) index, Enhanced Liver Fibrosis (ELF) test, and liver stiffness by vibration-controlled transient elastography (LS by VCTE). The performance of these tests to discriminate advanced fibrosis, either alone or in combinations, was evaluated using areas under the receiver operating characteristic curve (AUROCs) with 5-fold cross-validation repeated 100 times. Of the 4,404 patients screened for these trials, 3,202 had evaluable biopsy data: 940 with F0-F2 fibrosis and 2,262 with F3-F4 fibrosis. Significant differences between median values of NITs for patients with F0-F2 versus F3-F4 fibrosis were observed: -0.972 versus 0.318 for NFS, 1.18 versus 2.20 for FIB-4, 9.22 versus 10.39 for ELF, and 8.8 versus 16.5 kPa for LS by VCTE (all P < 0.001). AUROCs ranged from 0.75 to 0.80 to discriminate advanced fibrosis. FIB-4 followed by an LS by VCTE or ELF test in those with indeterminate values (FIB-4 between 1.3 and 2.67) maintained an acceptable performance while reducing the rate of indeterminate results. Conclusion: Among patients being considered for enrollment into clinical trials, NITs alone or in combination can reduce the need for liver biopsy to discriminate advanced fibrosis caused by NASH. The predictive value of these tests for general screening will require confirmation in a real-world population.

Assay validation and clinical performance of chronic inflammatory and chemokine biomarkers of NASH fibrosis

Nonalcoholic steatohepatitis (NASH) is a chronic liver disease that can lead to cirrhosis, liver transplant, and even hepatocellular carcinoma. While liver biopsy remains the reference standard for disease diagnosis, analytical and clinical development of non-invasive soluble biomarkers of NASH are of great importance to advance the field. To this end, we performed analytical and clinical validation on a series of pro-inflammatory cytokines and chemokines implicated hepatic inflammation; IL-6, CRP, TNFα, MCP-1, MIP-1β, eotaxin, VCAM-1. Biomarker assays were validated for accuracy and precision. Clinical performance was evaluated in a random sample of 52 patients with biopsy-proven NAFLD/NASH. Patients were categorized into three groups according to their fibrosis stage; advanced (F3-F4), mild (F1-2) and no (F0) fibrosis. Serum IL-6 was increased in patients with advanced fibrosis (2.71 pg/mL; 1.26 pg/mL; 1.39 pg/mL p<0.01) compared to patients with mild or no fibrosis respectively. While, there was no significant difference noted in CRP, TNFα, MCP-1, MIP-1β, eotaxin among the three groups, VCAM-1 levels were increased by 55% (p<0.01) and 40% (p<0.05) in the advanced cohort compared to the mild and no fibrosis groups respectively. VCAM-1 also displayed good clinical performance as a biomarker of advanced fibrosis with an area under the receiver operating curve of 0.87. The VCAM-1 assay demonstrated robust accuracy and precision, and VCAM-1 outperformed IL-6, CRP, TNFα, and the chemokines MCP-1, MIP-1β, and eotaxin as a biomarker of advanced fibrosis in NASH. Addition of biomarkers such as IL-6 and VCAM-1 to panels may yield increased sensitivity and specificity for staging of NASH.

Hepatocellular carcinoma as a leading cause of cancer-related deaths in Japanese type 2 diabetes mellitus patients

BACKGROUND

We reported a cross-sectional study on causes of liver injury in Japanese type 2 diabetes mellitus (T2D) patients (JG 2013). We assessed overall and cause-specific mortality risk during follow-up of patients enrolled in JG 2013.

METHODS

This was a longitudinal, multicenter cohort study. Of the 5642 Japanese T2D patients who visited T2D clinics of nine hospitals in the original study, 3,999 patients were followed up for an average of 4.5 years. Expected deaths in T2D patients were estimated using age-specific mortality rates in the general population (GP) of Japan. Standardized mortality ratios (SMRs) were calculated to compare mortality between T2D patients and GP.

RESULTS

All-cancer mortality was significantly higher in T2D patients than in the GP [SMR 1.58, 95% confidence interval (CI) 1.33-1.87]. Among malignancies, hepatocellular carcinoma (HCC) conferred the highest mortality risk in T2D patients (SMR 3.57, 95% CI 2.41-5.10). HCC-associated mortality risk in T2D patients remained significantly high (SMR 2.56, 95% CI 1.64-3.97) after adjusting for high positivity rates of hepatitis B surface antigen (1.7%) and anti-hepatitis C virus (5.3%). In T2D patients with platelet counts < 200 × 10³/μl, SMR of HCC increased from 3.57 to 6.58 (95% CI 4.34-9.58). T2D patients with platelet count > 200 × 10³/μl showed no increase in mortality risk (SMR 0.68) of HCC.

CONCLUSIONS

HCC-associated mortality risk was the highest among all cancers in Japanese T2D patients. Regular follow-up may be important for T2D patients with platelet counts < 200 × 10³/μl for early detection of HCC.

Accuracy of non-invasive scoring systems for diagnosing non-alcoholic steatohepatitis-related fibrosis: Multicenter validation study

AIM

Hepatic fibrosis is the most important factor for estimating the prognosis of patients with non-alcoholic fatty liver disease (NAFLD). A novel non-invasive scoring system, the FM-fibro index, showed high accuracy in a pilot study. The purpose of this study was to validate the efficacy of the FM-fibro index in a multicenter cohort.

METHODS

Among 18 institutions, we analyzed 400 Japanese patients with biopsy-proven NAFLD. We evaluated the accuracies of the FM-fibro index, CA-fibro index, and European Liver Fibrosis (ELF) panel by area under the receiver operator characteristics curves (AUROC). The FM-fibro index includes three formulas for type IV collagen 7S, hyaluronic acid, and vascular cell adhesion molecule-1.

RESULTS

Among 400 patients, 205 were women, and the median age was 56 years. The histological distribution of Matteoni types 1, 2, 3, and 4 was 11, 40, 15, and 334, and the distribution of hepatic fibrosis stages 0 to 4 was 67, 183, 55, 63, and 32, respectively. The AUROCs of the FM-fibro index, CA-fibro index, and ELF panel for non-alcoholic steatohepatitis (NASH)-related fibrosis were 0.7178/0.7095/0.7065, 0.7093, and 0.7245, respectively. The sensitivity and specificity of the FM-fibro index for predicting NASH-related fibrosis was 0.5359/0.5210/0.4641 and 0.8333/0.8182/0.8788, respectively. The accuracy of the FM-fibro index was not significantly different from that of the CA-fibro index or the ELF panel.

CONCLUSIONS

The FM-fibro index can predict NASH-related fibrosis with sufficient accuracy compared with previous scoring systems. Further analyses that verify the accuracy of the FM-fibro index to distinguish significant or advanced fibrosis in patients with NAFLD are awaited. (UMIN-CTR: UMIN000018158).

Efficacy and safety of canagliflozin in type 2 diabetes mellitus patients with biopsy-proven nonalcoholic steatohepatitis classified as stage 1-3 fibrosis

AIM

Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), is known to be associated with type 2 diabetes mellitus (T2DM) in high rate. The improvement in hepatic function due to sodium-glucose co-transporter 2 (SGLT2) inhibitors has been reported in T2DM patients with and without NAFLD. However, only a few studies have attempted to evaluate the role of SGLT2 inhibitors in T2DM patients with biopsy-proven NASH, and no detailed prospective studies including the individual hepatic fibrosis stage have been reported. Therefore, we investigated the effect of canagliflozin on hepatic function in T2DM patients with biopsy-confirmed NASH.

METHODS

T2DM patients with NASH (hepatic fibrosis stage 1-3 confirmed via liver biopsy, n=10) were enrolled and received canagliflozin (100 mg) once a day for 12 weeks. The primary end point was change in serum alanine aminotransferase (ALT) levels from baseline to week 12. Secondary end points were liver function/fibrosis markers, metabolic parameters, and safety.

RESULTS

The change in ALT from baseline to week 12 was -23.9 U/L (95% CI -48.1 to 0.3, P=0.0526). Significant improvements in several hepatic function/fibrosis markers, such as aspartate aminotransferase, fibrosis-4 index, and FM-fibro index, and metabolic parameters including hemoglobin A1c and body weight were found. No serious or liver-related adverse events were reported. Regarding individual patients, different trends in ALT-lowering effects between stage 1 and stage 2/3 subjects were observed; the degree of ALT-lowering effect tended to be greater in the stage 1 group than in the stage 2/3 group.

CONCLUSION

Our results suggest that canagliflozin is effective and well-tolerated in patients with T2DM and NASH. Canagliflozin may be useful for the treatment of T2DM patients with NASH, especially those in early stages of NASH.

Wisteria floribunda agglutinin-positive Mac-2-binding protein and type 4 collagen 7S: useful markers for the diagnosis of significant fibrosis in patients with non-alcoholic fatty liver disease

BACKGROUND AND AIM

The fibrosis stage of liver is associated with the long-term outcomes in patients with non-alcoholic fatty liver disease (NAFLD). However, significant fibrosis, defined as fibrosis stages 2-4, is associated with an elevated risk of progression to severe liver disease; there have been scant reports about diagnosing significant fibrosis. We compare the noninvasive method and aim to identify appropriate liver fibrosis markers for detecting significant fibrosis in NAFLD patients.

METHODS

We compared the usefulness of liver fibrosis markers (Wisteria floribunda agglutinin-positive Mac-2-binding protein [WFA⁺ -M2BP], type 4 collagen 7S, etc.), clinical scoring systems, and liver stiffness measurement obtained using vibration-controlled transient elastography and magnetic resonance imaging-based magnetic resonance elastography in the same individuals and identified the most appropriate noninvasive method for detecting significant fibrosis in 165 patients with liver biopsy-diagnosed NAFLD.

RESULTS

The area under the receiver operating characteristic curve based on the serum cutoff index values of WFA⁺ -M2BP/the serum levels of type IV collagen 7S for the diagnosis of significant fibrosis was 0.832 (95% confidence interval: 0.771-0.894)/0.837 (95% confidence interval: 0.778-0.898). "WFA⁺ -M2BP (cutoff index) ≥ 0.83 or type IV collagen 7S ≥ 5.2 ng/mL" showed a high sensitivity (91.4%) and negative predictive value (87.9%) for the diagnosis of significant fibrosis.

CONCLUSIONS

We showed that serum WFA⁺ -M2BP or type IV collagen 7S levels serve as useful independent markers for detecting significant fibrosis and that use of both WFA⁺ -M2BP and type IV collagen 7S together increased the sensitivity and negative predictive value for the diagnosis of liver fibrosis. These results need to be validated in larger populations from multiple clinical centers.

CD36 palmitoylation disrupts free fatty acid metabolism and promotes tissue inflammation in non-alcoholic steatohepatitis

BACKGROUND AND AIMS

Fatty acid translocase CD36 (CD36) is a membrane protein with multiple immuno-metabolic functions. Palmitoylation has been suggested to regulate the distribution and functions of CD36, but little is known about its significance in non-alcoholic steatohepatitis (NASH).

METHODS

Human liver tissue samples were obtained from patients undergoing liver biopsy for diagnostic purposes. CD36 knockout mice were injected with lentiviral vectors expressing wild-type CD36 or CD36 with mutated palmitoylation sites. Liver histology, immunofluorescence, mRNA expression profile, subcellular distributions and functions of CD36 protein were assessed.

RESULTS

The localization of CD36 on the plasma membrane of hepatocytes was markedly increased in patients with NASH compared to patients with normal liver and those with simple steatosis. Increased CD36 palmitoylation and increased localization of CD36 on the plasma membrane of hepatocytes were also observed in livers of mice with NASH. Furthermore, inhibition of CD36 palmitoylation protected mice from developing NASH. The absence of palmitoylation decreased CD36 protein hydrophobicity reducing its localization on the plasma membrane as well as in lipid raft of hepatocytes. Consequently, a lack of palmitoylation decreased fatty acid uptake and CD36/Fyn/Lyn complex in HepG2 cells. Inhibition of CD36 palmitoylation not only ameliorated intracellular lipid accumulation via activation of the AMPK pathway, but also inhibited the inflammatory response through the inhibition of the JNK signaling pathway.

CONCLUSIONS

Our findings demonstrate the key role of palmitoylation in regulating CD36 distributions and its functions in NASH. Inhibition of CD36 palmitoylation may represent an effective therapeutic strategy in patients with NASH.

LAY SUMMARY

Fatty acid translocase CD36 (CD36) is a multifunctional membrane protein which contributes to the development of liver steatosis. In the present study, we demonstrated that the localization of CD36 on the plasma membrane of hepatocytes is increased in patients with non-alcoholic steatohepatitis. Blocking the palmitoylation of CD36 reduces CD36 distribution in hepatocyte plasma membranes and protects mice from non-alcoholic steatohepatitis. The inhibition of CD36 palmitoylation not only improved fatty acid metabolic disorders but also reduced the inflammatory response in vitro and in vivo. The present study suggests that CD36 palmitoylation is important for non-alcoholic steatohepatitis development and inhibition of CD36 palmitoylation could be used to cure non-alcoholic steatohepatitis.

Noninvasive Tests Do Not Accurately Differentiate Nonalcoholic Steatohepatitis From Simple Steatosis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Nonalcoholic fatty liver disease is a rapidly increasing health problem. Liver biopsy analysis is the most sensitive test to differentiate between nonalcoholic steatohepatitis (NASH) and simple steatosis (SS), but noninvasive methods are needed. We performed a systematic review and meta-analysis of noninvasive tests for differentiating NASH from SS, focusing on blood markers.

METHODS

We performed a systematic search of the PubMed, Medline and Embase (1990-2016) databases using defined keywords, limited to full-text papers in English and human adults, and identified 2608 articles. Two independent reviewers screened the articles and identified 122 eligible articles that used liver biopsy as reference standard. If at least 2 studies were available, pooled sensitivity (sens_p) and specificity (spec_p) values were determined using the Meta-Analysis Package for R (metafor).

RESULTS

In the 122 studies analyzed, 219 different blood markers (107 single markers and 112 scoring systems) were identified to differentiate NASH from simple steatosis, and 22 other diagnostic tests were studied. Markers identified related to several pathophysiological mechanisms. The markers analyzed in the largest proportions of studies were alanine aminotransferase (sens_p, 63.5% and spec_p, 74.4%) within routine biochemical tests, adiponectin (sensp, 72.0% and spec_p, 75.7%) within inflammatory markers, CK18-M30 (sens_p, 68.4% and spec_p, 74.2%) within markers of cell death or proliferation and homeostatic model assessment of insulin resistance (sens_p, 69.0% and spec_p, 72.7%) within the metabolic markers. Two scoring systems could also be pooled: the NASH test (differentiated NASH from borderline NASH plus simple steatosis with 22.9% sens_p and 95.3% spec_p) and the GlycoNASH test (67.1% sens_p and 63.8% spec_p).

CONCLUSION

In the meta-analysis, we found no test to differentiate NASH from SS with a high level of pooled sensitivity and specificity (≥80%). However, some blood markers, when included in scoring systems in single studies, identified patients with NASH with ≥80% sensitivity and specificity. Replication studies and more standardized study designs are urgently needed. At present, no marker or scoring system can be recommended for use in clinical practice to differentiate NASH from simple steatosis.

Obeticholic acid protects against hepatocyte death and liver fibrosis in a murine model of nonalcoholic steatohepatitis

Accumulating evidence has suggested that farnesoid X receptor (FXR) agonists, such as obeticholic acid (OCA) are therapeutically useful for non-alcoholic steatohepatitis (NASH). However, it is still unclear how FXR agonists protect against NASH and which cell type is the main target of FXR agonists. In this study, we examined the effects of OCA on the development of NASH using melanocortin 4 receptor-deficient (MC4R-KO) mice that progressively developed hepatic steatosis and NASH on Western diet (WD). Treatment with OCA effectively prevented chronic inflammation and liver fibrosis in WD-fed MC4R-KO mice with only marginal effect on body weight and hepatic steatosis. Hepatic crown-like structure (hCLS) is a unique histological structure characteristic of NASH, which triggers hepatocyte death-induced interstitial fibrosis. Intriguingly, treatment with OCA markedly reduced hCLS formation even after MC4R-KO mice developed NASH, thereby inhibiting the progression of liver fibrosis. As its mechanism of action, OCA suppressed metabolic stress-induced p53 activation and cell death in hepatocytes. Our findings in this study highlight the role of FXR in hepatocytes in the pathogenesis of NASH. Collectively, this study demonstrates the anti-fibrotic effect of OCA in a murine model of NASH with obesity and insulin resistance, which suggests the clinical implication for human NASH.

A simple scoring system using type IV collagen 7S and aspartate aminotransferase for diagnosing nonalcoholic steatohepatitis and related fibrosis

BACKGROUND

Recently we reported novel noninvasive scoring systems for diagnosing nonalcoholic steatohepatitis (NASH) and related fibrosis, namely FM-NASH index and FM-fibro index. They are highly accurate, however, they contain some items not widely used in clinical practice and require six or more items to diagnose both NASH and related fibrosis. By focusing on widely used items, we tried to identify convenient markers in common with the both diagnoses.

METHODS

To explore the markers for NASH and related fibrosis in nonalcoholic fatty liver disease (NAFLD) patients, we used data of 24 clinical items in our previous report. By logistic regression analysis, we identified items suitable for the both diagnoses. We then evaluated their accuracies by area under the receiver operator characteristic curves (AUROCs) on independent validation data.

RESULTS

We identified the combination of type IV collagen 7S and aspartate aminotransferase (AST) as the predictor both for NASH and related fibrosis. We developed a scoring system based on the combination and evaluated the prediction accuracy: the AUROCs for training/validation data sets are 0.857/0.769 for NASH and 0.918/0.842 for NASH-related fibrosis. The former was higher than that of NAFIC score, and the latter was higher than those of existing fibrosis markers: BARD score, FIB-4 index and NAFLD fibrosis score but lower than FM-fibro index.

CONCLUSIONS

The scoring system using type IV collagen 7S and AST named CA index can predict both NASH and related fibrosis in NAFLD patients with sufficient accuracy and could be a convenient diagnostic and screening tool for NASH and related fibrosis. The scoring system needs to be validated in independent larger populations from multiple clinical centers.

Assessment of transient elastography in Japanese patients with non-alcoholic fatty liver disease

AIM

Transient elastography (TE) is a non-invasive method for predicting liver fibrosis. However, there are limited data regarding the performance of TE in Japanese patients with non-alcoholic fatty liver disease (NAFLD). We aimed to evaluate the association between liver stiffness measurement (LSM) by TE and liver fibrosis stage, and define a cut-off value for predicting liver fibrosis.

METHODS

A total of 171 Japanese patients with biopsy-proven NAFLD underwent LSM using TE with FibroScan. The area under the receiver operating characteristic curve of LSM and other non-invasive markers of liver fibrosis were compared to determine the most accurate method of predicting liver fibrosis.

RESULTS

Liver stiffness measurement significantly correlated with fibrosis stage (P < 0.001). The areas under the receiver operating characteristic curve of LSM for fibrosis stage ≥1 and ≥3 was 0.85 and 0.91, respectively and were higher than those of the aspartate aminotransferase/alanine aminotransferase ratio, aspartate aminotransferase to platelet ratio index, fibrosis-4 index, and NAFLD fibrosis score. The best cut-off values of LSM fibrosis stage ≥1 and ≥3 were 7.2 kPa (sensitivity 78.5%, specificity 78.3%) and 10.0 kPa (sensitivity 89.5%, specificity 87.6%), respectively. The combination of LSM (≥10 kPa) and type IV collagen 7 s (≥6.0 ng/mL) had a specificity of 97.6% for advanced fibrosis. The LSM in patients with high alanine aminotransferase levels or high body mass index was associated with false positive results regarding advanced fibrosis.

CONCLUSIONS

In NAFLD patients, TE has excellent utility for the assessment of liver fibrosis, particularly for advanced stage cases. The cut-off value of LSM by TE for predicting liver fibrosis stage ≥3 is 10.0 kPa in Japanese NAFLD patients.

Serum vascular cell adhesion molecule-1 predicts significant liver fibrosis in non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and is strongly associated with obesity, dyslipidemia and insulin resistance. NAFLD often presents as simple steatosis (NAFL) but can progress to non-alcoholic steatohepatitis (NASH) and fibrosis. Current non-invasive biomarkers are not tailored to identify significant (⩾F2) fibrosis, although recent guidelines recommend a stringent follow-up of this patient population. We and others have reported on the role of pathological angiogenesis in the pathogenesis of NAFLD, highlighting pro-angiogenic factors as potential diagnostic markers.

OBJECTIVE

To investigate the applicability of angiogenic and endothelial dysfunction markers as non-invasive diagnostic tools for NASH or NASH-associated fibrosis in obese patients.

METHODS

In a prospective cross-sectional study, male patients undergoing bariatric surgery (n=61) and control patients (n=35) were recruited. Serum protein levels and visceral adipose tissue gene expression of endothelial dysfunction and angiogenic markers were analyzed by multiplex bead-based assay and quantitative RT-PCR, respectively. For validation, we recruited a second cohort of patients undergoing bariatric surgery (n=40) and a cohort of NAFLD patients from our outpatient clinic (n=30).

RESULTS

We identified serum vascular cell adhesion molecule-1 (VCAM-1) as an independent predictor for ⩾F2 fibrosis (median 14.0 vs 8.7 ng ml^-1 in patients with and without significant fibrosis; P<0.0001) with an area under the receiver-operating characteristics (AUROC) curve of 0.80. The cutoff point of 13.2 ng ml^-1 showed a sensitivity of 80% and specificity of 83%. In line with these results, VCAM-1 visceral adipose tissue gene expression was also elevated in patients with fibrosis (P=0.030). In the bariatric surgery and clinical validation cohorts, VCAM-1 displayed similar AUROCs of 0.89 and 0.85, respectively.

CONCLUSIONS

VCAM-1 levels are able to accurately predict significant (⩾F2) fibrosis in NAFLD patients.

lncRNA co-expression network model for the prognostic analysis of acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous hematologic malignancy with great variability of prognostic behaviors. Previous studies have reported that long non-coding RNAs (lncRNAs) play an important role in AML and may thus be used as potential prognostic biomarkers. However, thus use of lncRNAs as prognostic biomarkers in AML and their detailed mechanisms of action in this disease have not yet been well characterized. For this purpose, in the present study, the expression levels of lncRNAs and mRNAs were calculated using the RNA-seq V2 data for AML, following which a lncRNA-lncRNA co-expression network (LLCN) was constructed. This revealed a total of 8 AML prognosis-related lncRNA modules were identified, which displayed a significant correlation with patient survival (p≤0.05). Subsequently, a prognosis-related lncRNA module pathway network was constructed to interpret the functional mechanism of the prognostic modules in AML. The results indicated that these prognostic modules were involved in the AML pathway, chemokine signaling pathway and WNT signaling pathway, all of which play important roles in AML. Furthermore, the investigation of lncRNAs in these prognostic modules suggested that an lncRNA (ZNF571-AS1) may be involved in AML via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway by regulating KIT and STAT5. The results of the present study not only provide potential lncRNA modules as prognostic biomarkers, but also provide further insight into the molecular mechanisms of action of lncRNAs.

Classification of patients with non-alcoholic fatty liver disease using rapid immunoassay of serum type IV collagen compared with liver histology and other fibrosis markers

AIM

Non-alcoholic fatty liver disease (NAFLD) can progress to non-alcoholic fatty liver (NAFL) or non-alcoholic steatohepatitis (NASH). We investigated the association among serum type IV collagen level, liver histology, and other fibrosis markers in NAFLD progression.

METHODS

We evaluated 184 patients diagnosed with NAFLD following biopsy, including 89 males and 95 females with an average age of 52.6 and 62.6 years, respectively. Non-alcoholic fatty liver disease was classified as NAFL or NASH using Matteoni's classification, and the grade and stage of NASH were assessed using Brunt's classification. Serum type IV collagen was measured by a rapid and sensitive latex particle-enhanced turbidimetric immunoassay.

RESULTS

Forty-two patients with NAFL and 142 patients with NASH were included in this study. Compared with patients with NAFL, patients with NASH showed more significant liver function disorder and increased expression of fibrosis markers including type IV collagen, collagen 7S, Mac2-binding protein (M2BP), and hyaluronic acid (HA). Expression of type IV collagen and collagen 7S, but not M2BP and HA, was more significantly elevated in patients with stage 1 NASH than in patients with NAFL, indicating that type IV collagen and collagen 7S may be better discriminators of NASH and NAFL than M2BP and HA at an early stage of fibrosis. When patients were stratified by NAFLD activity score, type IV collagen and collagen 7S were significantly elevated as NAFLD activity score progressed, whereas M2BP and HA expression were not significantly elevated.

CONCLUSION

Type IV collagen may be a useful measure of NASH severity as latex particle-enhanced turbidimetric immunoassay-based rapid type IV collagen assay can be carried out routinely.

Multiplex Serum Protein Analysis Identifies Novel Biomarkers of Advanced Fibrosis in Patients with Chronic Liver Disease with the Potential to Improve Diagnostic Accuracy of Established Biomarkers

Background and Aims

Non-invasive markers of liver fibrosis are urgently required, especially for use in non-specialist settings. The aim of this study was to identify novel serum biomarkers of advanced fibrosis.

Methods

We performed an unbiased screen of 120 serum analytes including cytokines, chemokines and proteases in 70 patients (35 without fibrosis, 35 with cirrhosis on biopsy), and selected a panel of 44 candidate biomarkers, which were subsequently measured in a mixed-etiology cohort of 432 patients with known serum HA, PIIINP and TIMP1 (which comprise the validated Enhanced Liver Fibrosis (ELF) test). Multivariate logistic regression modelling was used to generate models for the prediction of advanced or significant fibrosis (METAVIR ≥F3 and ≥F2, respectively); in addition to identifying biomarkers of disease activity and steatohepatitis.

Results

Seventeen analytes were significantly differentially expressed between patients with no advanced fibrosis and patients with advanced fibrosis, the most significant being hyaluronic acid (HA) and matrix metalloproteinase (MMP) 7 (p = 2.9E-41 and p = 1.0E-26, respectively). The optimal model for the prediction of advanced fibrosis comprised HA, MMP7, MMP1, alphafetoprotein (AFP) and the AST to platelet ratio index (APRI). We demonstrate enhanced diagnostic accuracy (AUROC = 0.938) compared to a model comprising HA, PIIINP and TIMP1 alone (ELF) (AUROC = 0.898, p<0.0001, De Long’s test).

Conclusions

We have identified novel serum biomarkers of advanced liver fibrosis, which have the potential to enhance the diagnostic accuracy of established biomarkers. Our data suggest MMP7 is a valuable indicator of advanced fibrosis and may play a role in liver fibrogenesis.

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.