Development and Validation of a Scoring System, Based on Genetic and Clinical Factors, to Determine Risk of Steatohepatitis in Asian Patients with Nonalcoholic Fatty Liver Disease

Global Epidemiology and Implications of PNPLA3 I148M Variant in Metabolic Dysfunction-Associated Steatotic Liver Disease: A Systematic Review and Meta-analysis

Background & Aims

PNPLA3 rs738409 variant is a risk factor for onset and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to assess its global prevalence, clinical and histological characteristics, and long-term outcomes in patients with MASLD.

Methods

PubMed and Embase databases were searched until December 30, 2023, for observational studies on PNPLA3 genotyped adults with MASLD. Proportions were pooled using a generalized linear mixed model with Clopper-Pearson intervals. Continuous and dichotomous variables were analyzed using the DerSimonian-Laird method. International Prospective Register of Systematic Reviews registration number: CRD42023449838.

Results

A total of 109 studies involving 118,302 individuals with MASLD were identified. The overall minor allele frequency of the G allele [MAF(G)] at PNPLA3 was 0.45 (95% confidence interval [CI]: 0.43; 0.48) with high heterogeneity (I2 = 98%). The highest MAF(G) was found in Latin America (0.63) and the lowest in Europe (0.38). No African countries were identified. Carriers of the PNPLA3 variant had reduced adiposity, altered fat metabolism, and worse liver damage/histology than noncarriers. There was significant heterogeneity in the clinical/histological analyses (I2 > 50%). Only the PNPLA3 GG genotype was associated with higher mortality and liver-related events with no heterogeneity (I2 = 0%). Metaregressions showed the influence of adiposity, age, diabetes mellitus, and glucose on some PNPLA3 expression parameters. Overall, there was a moderate risk of bias in the included studies.

Conclusions

This study reveals the global pattern of PNPLA3 and its clinical, histological, and outcome implications in MASLD. Patients with MASLD and PNPLA3 variant have different clinical features and worse liver severity, and only PNPLA3 GG has a higher risk of mortality and liver outcomes. Our findings highlight the importance of PNPLA3 genotyping in clinical trials and advocate for personalized medicine approaches.

Noninvasive identification of metabolic dysfunction-associated steatohepatitis (INFORM MASH): a retrospective cohort and disease modeling study

BACKGROUND

Using common clinical parameters, we aimed to noninvasively identify and predict metabolic dysfunction-associated steatohepatitis (MASH)/MASH with clinically significant fibrosis.

RESEARCH DESIGN AND METHODS

Patients aged ≥18 with electronic health record (EHR) documented liver function tests and liver biopsies between 2016 and 2021 were retrospectively identified from the Geisinger Health System Research Liver Registry. MASH cases were confirmed using the nonalcoholic fatty liver disease (NAFLD) activity score. Training and validation datasets were used to create an algorithm/predictive model assessing EHR-derived predictors of MASH/MASH with clinically significant fibrosis (fibrosis stage F2-F4). Predictive accuracy was evaluated using the area under the curve.

RESULTS

The analysis included 2698 patients. We created a composite likelihood score using variables significant for MASH and/or MASH with clinically significant fibrosis: liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST]), prior year AST, metabolic disease, pulse (heart rate), and body mass index. The score had higher sensitivity and specificity for predicting MASH than Fibrosis-4 (FIB-4) Index, AST to platelet ratio index (APRI), and NAFLD fibrosis score (NFS); sensitivity and specificity were comparable to FIB-4 and APRI for predicting MASH with clinically significant fibrosis but superior to NFS.

CONCLUSION

The composite likelihood score could potentially be a tool for early MASH screening.

Integrating PNPLA3 into clinical risk prediction

The PNPLA3-rs738409-G variant was the first common variant associated with hepatic fat accumulation and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Nevertheless, to date, the clinical translation of this discovery has been minimal because it has not yet been clearly demonstrated where the genetic information may play an independent and additional role in clinical risk prediction. In this mini-review, we will discuss the most relevant evidence regarding the potential integration of the PNPLA3 variant into scores and algorithms for liver disease diagnostics and risk stratification, specifically focusing on MASLD but also extending to liver diseases of other etiologies. The PNPLA3 variant adds little in diagnosing the current state of the disease, whether in terms of presence/absence of metabolic dysfunction-associated steatohepatitis or the stage of fibrosis. While it can play an important role in prediction, allowing for the early definition of risk profiles that enable tailored monitoring and interventions over time, this is most valuable when applied to populations with relatively high pre-test probability of having significant fibrosis based on either non-invasive tests (e.g. Fibrosis-4) or demographics (e.g. diabetes). Indeed, in this context, integrating FIB4 with the PNPLA3 genotype can refine risk stratification, though there is still no evidence that genetic information adds to liver stiffness determined by elastography. Similarly, in patients with known liver cirrhosis, knowing the PNPLA3 genotype can play a role in predicting the risk of hepatocellular carcinoma, while more doubts remain about the risk of decompensation.

Evaluation of Liver Fibrosis through Noninvasive Tests in Steatotic Liver Disease

Liver fibrosis, a critical predictor of the prognosis of metabolic dysfunction-associated steatotic liver disease (MASLD), is traditionally diagnosed via biopsy. Nevertheless, non-invasive alternatives, such as serum biomarkers, vibration-controlled transient elastography, and magnetic resonance elastography, have become prominent because of the limitations of biopsies. Serum biomarkers, such as fibrosis-4 index and NFS Score, are also used widely, offering reliable diagnostic performance for advanced fibrosis. Vibration-controlled transient elastography and shear wave elastography provide further non-invasive evaluations with high diagnostic accuracy, particularly for advanced fibrosis, but the results may be affected by factors such as obesity. Magnetic resonance elastography, with superior diagnostic accuracy and operator independence, is a promising method, but its high cost and limited availability restrict its widespread use. Emerging algorithms, such as NIS4, FAST, or MAST score, have strong potential in identifying high-risk metabolic dysfunction-associated steatohepatitis patients. The integration of multiple non-invasive methods can optimize diagnostic accuracy, reducing the need for invasive biopsies while identifying patients at risk of liver-related complications. Further research is needed to refine these diagnostic tools and improve accessibility.

Are we ready for genetic testing in metabolic dysfunction-associated steatotic liver disease?

Metabolic dysfunction-associated steatotic liver disease (MASLD), with its steadily increasing prevalence, represents now a major problem in public health. A proper referral could benefit from tools allowing more precise risk stratification. To this end, in recent decades, several genetic variants that may help predict and refine the risk of development and progression of MASLD have been investigated. In this review, we aim to discuss the role genetics in MASLD plays in everyday clinical practice. We performed a comprehensive literature search of PubMed for relevant publications. Available evidence highlights the emergence of genetic-based noninvasive algorithms for diagnosing fatty liver, metabolic dysfunction-associated steatohepatitis, fibrosis progression and occurrence of liver-related outcomes including hepatocellular carcinoma. Nevertheless, their accuracy is not optimal and application in everyday clinical practice remains challenging. Furthermore, susceptible genetic markers have recently become subjects of great scientific interest as therapeutic targets in precision medicine. In conclusion, decisional algorithms based on genetic testing in MASLD to facilitate the clinician decisions on management and treatment are under growing investigation and could benefit from artificial intelligence methodology.

MBOAT7 rs641738 Variant Is Not Associated with an Increased Risk of Hepatocellular Carcinoma in a Latin American Cohort

BACKGROUND

The rs641738 C > T single-nucleotide polymorphism of MBOAT7 has been associated with hepatocellular carcinoma (HCC) and nonalcoholic fatty liver disease (NAFLD). Latin Americans have high rates of HCC and NAFLD, but no assessment between MBOAT7 and HCC has been performed in this population.

AIMS

We provide the first assessment of the impact of MBOAT7 on HCC risk in Latin Americans.

METHODS

Patients were prospectively recruited into the ESCALON network, designed to collect samples from Latin American patients with HCC in 6 South American countries (Argentina, Ecuador, Brazil, Chile, Peru, and Colombia). A European cohort and the general Hispanic population of gnomAD database were included for comparison. Associations between HCC and MBOAT7 were evaluated using logistic regression.

RESULTS

In total, 310 cases of HCC and 493 cases of cirrhosis without HCC were assessed. The MBOAT7 TT genotype was not predictive of HCC in Latin Americans (TT vs CC OR adjusted = 1.15, 95% CI 0.66-2.01, p = 0.610) or Europeans (TT vs CC OR adjusted = 1.20, 95% CI 0.59-2.43, p = 0.621). No significant association was noted on subgroup analysis for NAFLD, viral hepatitis, or alcohol-related liver disease. The TT genotype was increased in the NAFLD-cirrhosis cohort of Latin Americans compared to a non-cirrhotic NAFLD cohort (TT vs CC + CT OR = 2.75, 95% CI 1.10-6.87, p = 0.031).

CONCLUSION

The rs631738 C > T allele of MBOAT7 was not associated with increased risk of HCC in Latin Americans or Europeans. An increase in the risk of cirrhosis was noted with the TT genotype in Latin Americans with NAFLD.

Predicted pro-inflammatory hs-CRP score and non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a major contributor to liver diseases globally, yet there are limited studies investigating the impact of diet and lifestyle factors on its development. This study aimed to examine the association between the prevalence of NAFLD and predicted pro-inflammatory high-sensitivity C-reactive protein (hs-CRP) score.

Methods

We included 1,076 Korean adults who underwent a medical examination at the Seoul National University Hospital Gangnam Healthcare Center in Korea between May and December 2011 and updated in 2021. The predicted pro-inflammatory hs-CRP score was derived from pro-inflammatory demographic, lifestyle, dietary, and anthropometric factors, and NAFLD was diagnosed using liver ultrasound. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of NAFLD odds according to predicted pro-inflammatory hs-CRP score were estimated using logistic regression at a two-sided P < 0.05.

Results

Among the 1,076 participants, 320 had NAFLD. The multivariable-adjusted ORs and 95% CIs for NAFLD by tertiles of predicted pro-inflammatory hs-CRP score were 1.00, 3.30 (2.06, 5.30), 18.25 (10.47, 31.81; P < 0.0001) in men and women combined, 1.00, 1.77 (1.10, 2.84), and 3.26 (2.02, 5.28; P < 0.0001) among men only, and 1.00, 3.03 (1.39, 6.62), and 16.71 (7.05, 39.63; P < 0.0001) among women only.

Conclusions

Predicted pro-inflammatory hs-CRP score was associated with higher odds of NAFLD. Adopting dietary and lifestyle changes related to lower inflammation might be a valuable strategy for preventing NAFLD.

MBOAT7 rs641738 (C>T) is associated with NAFLD progression in men and decreased ASCVD risk in elder Chinese population

Background and aim

The MBOAT7 rs641738 (C>T) variant has demonstrated an association with non-alcoholic fatty liver disease (NAFLD) in both adult and pediatric patients, while few studies have been conducted in elderly populations. Hence, a case-control study was undertaken to assess their correlation in elderly residents in a Beijing community.

Materials and methods

A total of 1,287 participants were included. Medical history, abdominal ultrasound, and laboratory tests were recorded. Liver fat content and fibrosis stage were detected by Fibroscan. Genotyping of genomic DNA was performed using the 96.96 genotyping integrated fluidics circuit.

Results

Of the recruited subjects, 638 subjects (56.60%) had NAFLD, and 398 subjects (35.28%) had atherosclerotic cardiovascular disease (ASCVD). T allele carriage was associated with higher ALT (p=0.005) and significant fibrosis in male NAFLD patients (p=0.005) compared to CC genotype. TT genotype was associated with reduced risk of metabolic syndrome (OR=0.589, 95%CI: 0.114-0.683, p=0.005) and type 2 diabetes (OR=0.804, 95%CI: 0.277-0.296, p=0.048) in NAFLD population when compared to the CC genotype. In addition, TT genotype was also associated with reduced risk of ASCVD (OR=0.570, 95%CI:0.340-0.953, p=0.032) and less obesity (OR=0.545, 95%CI: 0.346-0.856, p=0.008) in the whole population.

Conclusion

MBOAT7 rs641738 (C>T) variant was associated with fibrosis in male NAFLD patients. The variant also reduced risk of metabolic traits and type 2 diabetes in NAFLD and ASCVD risk in Chinese elders.

Long-Term Effect of PNPLA3 on the Aggravation of Nonalcoholic Fatty Liver Disease in a Biopsy-Proven Cohort

The PNPLA3 rs738409 G allele increases the risk of not only nonalcoholic fatty liver disease (NAFLD) but also nonalcoholic steatohepatitis (NASH) or fibrosis.¹ It also affects the prognosis of patients with NAFLD in specific conditions. After liver transplantation, patients with NAFLD carrying the rs738409 GG genotype have a higher risk of graft steatosis² or development of hepatocellular carcinoma.³ In addition, rs738409 modifies the effects of medical intervention: patients with NAFLD carrying the GG genotype showed a lower effect of omega-3 polyunsaturated fatty acid treatment on the reduction of liver fat;⁴ in contrast, they were more sensitive to the beneficial effects of lifestyle modifications.^5,6.

Baseline Tyrosine Level Is Associated with Dynamic Changes in FAST Score in NAFLD Patients under Lifestyle Modification

Noninvasive risk stratification is a challenging issue in the management of patients with nonalcoholic fatty liver disease (NAFLD). This study aimed to identify multiomics-based predictors of NAFLD progression, as assessed by changes in serial FibroScan-aspartate aminotransferase (FAST) scores during lifestyle modification. A total of 266 patients with available metabolomics and genotyping data were included. The follow-up sub-cohort included patients with paired laboratory and transient elastography results (n = 160). The baseline median FAST score was 0.37. The PNPLA3 rs738409 genotype was significantly associated with a FAST score > 0.35. Circulating metabolomics significantly associated with a FAST score > 0.35 included SM C24:0 (odds ratio [OR] = 0.642; 95% confidence interval [CI], 0.463-0.891), PC ae C40:6 (OR = 0.477; 95% CI, 0.340-0.669), lysoPC a C18:2 (OR = 0.570; 95% CI, 0.417-0.779), and tyrosine (OR = 2.743; 95% CI, 1.875-4.014). A combination of these metabolites and PNPLA3 genotype yielded a c-index = 0.948 for predicting a FAST score > 0.35. In the follow-up sub-cohort (median follow-up = 23.7 months), 47/76 patients (61.8%) with a baseline FAST score > 0.35 had a follow-up FAST score ≤ 0.35. An improved FAST score at follow-up was significantly associated with age, serum alanine aminotransferase, and tyrosine. In conclusion, baseline risk stratification in NAFLD patients may be assisted using a multiomics-based model. Particularly, patients with increased tyrosine may benefit from an earlier switch to pharmacologic approaches.

Review article: the role of HSD17B13 on global epidemiology, natural history, pathogenesis and treatment of NAFLD

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) occurs in around a quarter of the global population and is one of the leading causes of chronic liver disease. The phenotypic manifestation and the severity of NAFLD are influenced by an interplay of environmental and genetic factors. Recently, several inactivating variants in the novel 17-Beta hydroxysteroid dehydrogenase 13 (HSD17B13) gene have been found to be associated with a reduced risk of chronic liver diseases, including NAFLD.

AIMS

To review the existing literature on the epidemiology of HSD17B13 and discuss its role in the natural history, disease pathogenesis and treatment of NAFLD.

METHODS

We extensively searched relevant literature in PubMed, Google Scholar, clinicaltrials.gov and the reference list of articles included in the review.

RESULTS

HSD17B13 is a liver-specific, lipid droplet (LD)-associated protein that has enzymatic pathways involving steroids, pro-inflammatory lipid mediators and retinol. The estimated prevalence of the best characterised HSD17B13 variant (rs72613567) ranges from 5% in Africa to 34% in East Asia. Loss-of-function variants in HSD17B13 are protective against the progression of NAFLD from simple steatosis to non-alcoholic steatohepatitis (NASH), liver fibrosis, cirrhosis and hepatocellular carcinoma. Emerging data from mechanistic and preclinical studies with RNA interference (RNAi) and small molecule agents indicate that inhibiting HSD17B13 activity may prevent NAFLD progression.

CONCLUSIONS

The loss-of-function polymorphisms of the newly identified HSD17B13 gene mitigate the progression of NAFLD. It is important to understand the exact mechanism by which these variants exert a protective effect and implement the gathered knowledge in the treatment of NAFLD.

Genetic Polymorphisms and Diversity in Nonalcoholic Fatty Liver Disease (NAFLD): A Mini Review

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease with a wide spectrum of liver conditions ranging from hepatic steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma. The prevalence of NAFLD varies across populations, and different ethnicities have specific risks for the disease. NAFLD is a multi-factorial disease where the genetics, metabolic, and environmental factors interplay and modulate the disease's development and progression. Several genetic polymorphisms have been identified and are associated with the disease risk. This mini-review discussed the NAFLD's genetic polymorphisms and focusing on the differences in the findings between the populations (diversity), including of those reports that did not show any significant association. The challenges of genetic diversity are also summarized. Understanding the genetic contribution of NAFLD will allow for better diagnosis and management explicitly tailored for the various populations.

A machine-learning approach for nonalcoholic steatohepatitis susceptibility estimation

BACKGROUND

Nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease, can lead to advanced liver damage and has become an increasingly prominent health problem worldwide. Predictive models for early identification of high-risk individuals could help identify preventive and interventional measures. Traditional epidemiological models with limited predictive power are based on statistical analysis. In the current study, a novel machine-learning approach was developed for individual NASH susceptibility prediction using candidate single nucleotide polymorphisms (SNPs).

METHODS

A total of 245 NASH patients and 120 healthy individuals were included in the study. Single nucleotide polymorphism genotypes of candidate genes including two SNPs in the cytochrome P450 family 2 subfamily E member 1 (CYP2E1) gene (rs6413432, rs3813867), two SNPs in the glucokinase regulator (GCKR) gene (rs780094, rs1260326), rs738409 SNP in patatin-like phospholipase domain-containing 3 (PNPLA3), and gender parameters were used to develop models for identifying at-risk individuals. To predict the individual's susceptibility to NASH, nine different machine-learning models were constructed. These models involved two different feature selections including Chi-square, and support vector machine recursive feature elimination (SVM-RFE) and three classification algorithms including k-nearest neighbor (KNN), multi-layer perceptron (MLP), and random forest (RF). All nine machine-learning models were trained using 80% of both the NASH patients and the healthy controls data. The nine machine-learning models were then tested on 20% of both groups. The model's performance was compared for model accuracy, precision, sensitivity, and F measure.

RESULTS

Among all nine machine-learning models, the KNN classifier with all features as input showed the highest performance with 86% F measure and 79% accuracy.

CONCLUSIONS

Machine learning based on genomic variety may be applicable for estimating an individual's susceptibility for developing NASH among high-risk groups with a high degree of accuracy, precision, and sensitivity.

Advance of Serum Biomarkers and Combined Diagnostic Panels in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) affects approximately 25-30% population worldwide, which progresses from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma, and has complications such as cardiovascular events. Liver biopsy is still the gold standard for the diagnosis of NAFLD, with some limitations, such as invasive, sampling deviation, and empirical judgment. Therefore, it is urgent to develop noninvasive diagnostic biomarkers. Currently, a large number of NAFLD-related serum biomarkers have been identified, including apoptosis, inflammation, fibrosis, adipokines, hepatokines, and omics biomarkers, which could effectively diagnose NASH and exclude patients with progressive fibrosis. We summarized serum biomarkers and combined diagnostic panels of NAFLD, to provide some guidance for the noninvasive diagnosis and further clinical studies.

Membrane-bound O-acyltransferase 7 (MBOAT7)-driven phosphatidylinositol remodeling in advanced liver disease

Advanced liver diseases account for approximately 2 million deaths annually worldwide. Roughly, half of liver disease-associated deaths arise from complications of cirrhosis and the other half driven by viral hepatitis and hepatocellular carcinoma. Unfortunately, the development of therapeutic strategies to treat subjects with advanced liver disease has been hampered by a lack of mechanistic understanding of liver disease progression and a lack of human-relevant animal models. An important advance has been made within the past several years, as several genome-wide association studies have discovered that an SNP near the gene encoding membrane-bound O-acyltransferase 7 (MBOAT7) is associated with severe liver diseases. This common MBOAT7 variant (rs641738, C>T), which reduces MBOAT7 expression, confers increased susceptibility to nonalcoholic fatty liver disease, alcohol-associated liver disease, and liver fibrosis in patients chronically infected with viral hepatitis. Recent studies in mice also show that Mboat7 loss of function can promote hepatic steatosis, inflammation, and fibrosis, causally linking this phosphatidylinositol remodeling enzyme to liver health in both rodents and humans. Herein, we review recent insights into the mechanisms by which MBOAT7-driven phosphatidylinositol remodeling influences liver disease progression and discuss how rapid progress in this area could inform drug discovery moving forward.

Interaction effect between NAFLD severity and high carbohydrate diet on gut microbiome alteration and hepatic de novo lipogenesis

Nonalcoholic fatty liver disease (NAFLD) is associated with high carbohydrate (HC) intake. We investigated whether the relationship between carbohydrate intake and NAFLD is mediated by interactions between gut microbial modulation, impaired insulin response, and hepatic de novo lipogenesis (DNL). Stool samples were collected from 204 Korean subjects with biopsy-proven NAFLD (n = 129) and without NAFLD (n = 75). The gut microbiome profiles were analyzed using 16S rRNA amplicon sequencing. Study subjects were grouped by the NAFLD activity score (NAS) and percentage energy intake from dietary carbohydrate. Hepatic DNL-related transcripts were also analyzed (n = 90). Data from the Korean healthy twin cohort (n = 682), a large sample of individuals without NAFLD, were used for comparison and validation. A HC diet rather than a low carbohydrate diet was associated with the altered gut microbiome diversity according to the NAS. Unlike individuals from the twin cohort without NAFLD, the abundances of Enterobacteriaceae and Ruminococcaceae were significantly different among the NAS subgroups in NAFLD subjects who consumed an HC diet. The addition of these two microbial families, along with Veillonellaceae, significantly improved the diagnostic performance of the predictive model, which was based on the body mass index, age, and sex to predict nonalcoholic steatohepatitis in the HC group. In the HC group, two crucial regulators of DNL (SIRT1 and SREBF2) were differentially expressed among the NAS subgroups. In particular, kernel causality analysis revealed a causal effect of the abundance of Enterobacteriaceae on SREBF2 upregulation and of the surrogate markers of insulin resistance on NAFLD activity in the HC group. Consuming an HC diet is associated with alteration in the gut microbiome, impaired glucose homeostasis, and upregulation of hepatic DNL genes, altogether contributing to NAFLD pathogenesis.

Association of Inflammatory Cytokines With Non-Alcoholic Fatty Liver Disease

Background

Inflammatory cytokines have been considered to be significant factors contributing to the development and progression of non-alcoholic fatty liver disease (NAFLD). However, the role of inflammatory cytokines in NAFLD remains inconclusive.

Objective

This study aimed to evaluate the association between inflammatory cytokines and NAFLD.

Methods

PubMed, Web of Science, the Cochrane Library, and EMBASE databases were searched until 31 December 2021 to identify eligible studies that reported the association of inflammatory cytokine with NAFLD and its subtypes. We pooled odds ratios (ORs) and hazard risk (HRs) with 95% confidence intervals (CIs) and conducted heterogeneity tests. Sensitivity analysis and analysis for publication bias were also carried out.

Results

The search in the databases identified 51 relevant studies that investigated the association between 19 different inflammatory cytokines and NAFLD based on 36,074 patients and 47,052 controls. The results of the meta-analysis showed significant associations for C-reactive protein (CRP), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) with NAFLD (ORs of 1.41, 1.08, 1.50, 1.15 and 2.17, respectively). In contrast, we observed non-significant associations for interferon-γ (IFN-γ), insulin-like growth factor (IGF-II), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-7 (IL-7), interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-12 (IL-12), monocyte chemoattractant protein-1(MCP-1), and transforming growth factor-β (TGF-β) with NAFLD. Our results also showed that CRP, IL-1β, and TNF-α were significantly associated with non-alcoholic steatohepatitis (NASH) and hepatic fibrosis.

Conclusions

Our results indicated that increased CRP, IL‐1β, IL-6, TNF‐α, and ICAM-1 concentrations were significantly associated with increased risks of NAFLD. These inflammatory mediators may serve as biomarkers for NAFLD subjects and expect to provide new insights into the aetiology of NAFLD as well as early diagnosis and intervention.

Influence of Type 2 Diabetes in the Association of PNPLA3 rs738409 and TM6SF2 rs58542926 Polymorphisms in NASH Advanced Liver Fibrosis

Nonalcoholic steatohepatitis (NASH) is a leading cause of cirrhosis in western countries. Insulin resistance (IR), type 2 diabetes (T2D), and the polymorphisms patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 and transmembrane 6 superfamily member 2 (TM6SF2) rs58542926 are independent risk factors of NASH. Nevertheless, little is known about the interaction between IR and T2D with these polymorphisms in the pathogenesis of NASH and the development of advanced fibrosis. Thus, our study aimed to investigate this relationship. This is a cross-sectional study including NASH patients diagnosed by liver biopsy, at the Vall d’Hebron University Hospital. A total of 140 patients were included (93 T2D, 47 non-T2D). T2D (OR = 4.67; 95%CI 2.13−10.20; p < 0.001), PNPLA3 rs738409 and TM6SF2 rs58542926 polymorphisms (OR = 3.94; 95%CI 1.63−9.54; p = 0.002) were independently related with advanced liver fibrosis. T2D increased the risk of advance fibrosis on top of the two polymorphisms (OR = 14.69; 95%CI 3.03−77.35; p = 0.001 for PNPLA3 rs738409 and OR = 11.45; 95%CI 3.16−41.55; p < 0.001 for TM6SF2 rs58542926). In non-T2D patients, the IR (HOMA-IR ≥ 5.2, OR = 14.33; 95%CI 2.14−18.66; p = 0.014) increased the risk of advanced fibrosis when the polymorphisms were present (OR = 19.04; 95%CI 1.71−650.84; p = 0.042). The T2D and IR status increase the risk of advanced fibrosis in patients with NASH carrying the PNPLA3 rs738409 and/or TM6SF2 rs58542926 polymorphisms, respectively.

Recent Epidemiology and Risk Factors of Nonalcoholic Fatty Liver Disease

Because of the global obesity epidemic, the incidence and prevalence of nonalcoholic fatty liver disease (NAFLD) have increased worldwide, including among Koreans. Recently, the incidence rate of NAFLD in Korea was reported to be 45.1 per 1,000 person-years, and the prevalence as approximately 30% depending on the diagnostic methods used. The incidence of advanced fibrosis and hepatocellular carcinoma, as well as all-cause and liver-related mortality in NAFLD patients has increased substantially, imposing considerable public health costs in Korea. Genetic, demographic, environmental, and clinical factors are involved in the pathogenesis of NAFLD. Some genetic variants, such as patatin-like phospholipase domain-containing 3 (PNPLA-3) and sorting and assembly machinery component 50 (SAMM-50), play a major role in the occurrence of NAFLD. The risk of NAFLD and fibrosis increases with advancing age and in men. Nutritional factors, inadequate exercise, and sleep duration are also associated with increased risk of NAFLD. Obesity is a major risk factor for NAFLD; however, NAFLD in lean individuals has been noted in recent studies. Insulin resistance, type 2 diabetes, and metabolic syndrome and its components are closely associated with NAFLD development and liver fibrosis with various underlying mechanisms. Sarcopenia likely shares a common pathophysiology with NAFLD. The rapidly increasing incidence and prevalence of NAFLD and its complications, as well as the associated healthcare burden, warrant early assessment of NAFLD and its risk factors to prevent NAFLD-related complications in high risk groups.

Non-invasive tests of non-alcoholic fatty liver disease

ABSTRACT

For the detection of steatosis, quantitative ultrasound imaging techniques have achieved great progress in past years. Magnetic resonance imaging proton density fat fraction is currently the most accurate test to detect hepatic steatosis. Some blood biomarkers correlate with non-alcoholic steatohepatitis, but the accuracy is modest. Regarding liver fibrosis, liver stiffness measurement by transient elastography (TE) has high accuracy and is widely used across the world. Magnetic resonance elastography is marginally better than TE but is limited by its cost and availability. Several blood biomarkers of fibrosis have been used in clinical trials and hold promise for selecting patients for treatment and monitoring treatment response. This article reviews new developments in the non-invasive assessment of non-alcoholic fatty liver disease (NAFLD). Accumulating evidence suggests that various non-invasive tests can be used to diagnose NAFLD, assess its severity, and predict the prognosis. Further studies are needed to determine the role of the tests as monitoring tools. We cannot overemphasize the importance of context in selecting appropriate tests.

Insights into Nonalcoholic Fatty-Liver Disease Heterogeneity

The acronym nonalcoholic fatty-liver disease (NAFLD) groups a heterogeneous patient population. Although in many patients the primary driver is metabolic dysfunction, a complex and dynamic interaction of different factors (i.e., sex, presence of one or more genetic variants, coexistence of different comorbidities, diverse microbiota composition, and various degrees of alcohol consumption among others) takes place to determine disease subphenotypes with distinct natural history and prognosis and, eventually, different response to therapy. This review aims to address this topic through the analysis of existing data on the differential contribution of known factors to the pathogenesis and clinical expression of NAFLD, thus determining the different clinical subphenotypes observed in practice. To improve our understanding of NAFLD heterogeneity and the dominant drivers of disease in patient subgroups would predictably impact on the development of more precision-targeted therapies for NAFLD.

Genetics Is of the Essence to Face NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease worldwide. It is closely related to obesity, insulin resistance (IR) and dyslipidemia so much so it is considered the hepatic manifestation of the Metabolic Syndrome. The NAFLD spectrum extends from simple steatosis to nonalcoholic steatohepatitis (NASH), a clinical condition which may progress up to fibrosis, cirrhosis and hepatocellular carcinoma (HCC). NAFLD is a complex disease whose pathogenesis is shaped by both environmental and genetic factors. In the last two decades, several heritable modifications in genes influencing hepatic lipid remodeling, and mitochondrial oxidative status have been emerged as predictors of progressive hepatic damage. Among them, the patatin-like phospholipase domain-containing 3 (PNPLA3) p.I148M, the Transmembrane 6 superfamily member 2 (TM6SF2) p.E167K and the rs641738 membrane bound-o-acyltransferase domain-containing 7 (MBOAT7) polymorphisms are considered the most robust modifiers of NAFLD. However, a forefront frontier in the study of NAFLD heritability is to postulate score-based strategy, building polygenic risk scores (PRS), which aggregate the most relevant genetic determinants of NAFLD and biochemical parameters, with the purpose to foresee patients with greater risk of severe NAFLD, guaranteeing the most highly predictive value, the best diagnostic accuracy and the more precise individualized therapy.

The HSD17B13 rs72613567 variant is associated with lower levels of albuminuria in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Several susceptibility gene variants predisposing to nonalcoholic fatty liver disease (NAFLD) have been identified in chronic kidney disease (CKD). Evidence supports that 17-beta hydroxysteroid dehydrogenase 13 (HSD17B13) rs72613567 plays a role in NAFLD development by affecting lipid homeostasis. Since lipid droplets may accumulate in the kidneys and contribute to renal injury, we investigated the association between the HSD17B13 rs72613567 variant and markers of renal function/injury in NAFLD.

METHODS AND RESULTS

We measured estimated glomerular filtration rate (eGFR), urinary/serum neutrophil gelatinase-associated lipocalin (NGAL), and urinary albumin-to-creatinine ratio (u-ACR) in individuals with biopsy-proven NAFLD. Multivariable regression analyses were undertaken to examine the associations between the HSD17B13 rs72613567 variant and markers of renal function/injury. Individuals were stratified by HSD17B13 rs72613567 genotypes into -/-, A/- and A/A groups. HSD17B13 rs72613567 genotypes were not significantly associated with eGFR and urinary/serum NGAL levels. Conversely, the prevalence of abnormal albuminuria in the A/- + A/A group was lower than in the -/- group (4.92% vs. 19.35%, p = 0.001). Additionally, the mean u-ACR levels were lower among carriers of the A/- or A/A genotypes with coexisting hypertension or diabetes, than among those with the -/- genotype. The risk of abnormal albuminuria (adjusted-odds ratio 0.16, p = 0.001) remained significantly lower in the A/- + A/A group after adjustment for established renal risk factors and histologic severity of NAFLD.

CONCLUSION

HSD17B13 rs72613567: A allele is associated with a lower risk of having abnormal albuminuria, but not with lower eGFR or urinary/serum NGAL levels, in patients with biopsy-proven NAFLD.

Individualized Polygenic Risk Score Identifies NASH in the Eastern Asia Region: A Derivation and Validation Study

INTRODUCTION

Strong evidence indicates that multiple genetic and environmental risk factors play a role in the pathogenesis of nonalcoholic steatohepatitis (NASH). We aimed to develop and validate a novel nomogram, incorporating both genetic and clinical factors, for predicting NASH.

METHODS

A total of 1,070 Asian individuals with biopsy-confirmed nonalcoholic fatty liver disease (NAFLD) from 2 countries (China and South Korea) were recruited. The histological spectrum of NAFLD was classified according to the NASH clinical research network scoring system. The nomogram was developed in the Chinese training set (n = 402), and then, it was validated in both the Chinese internal validation set (n = 136) and the external Korean validation cohort (n = 532), respectively.

RESULTS

Sex, metabolic syndrome, insulin resistance, serum aspartate aminotransferase levels, and PNPLA3 (rs738409) and HSD17B13 (rs72613567) genetic variants were strongly associated with NASH. Based on their regression coefficients, we developed a nomogram with good discriminatory ability (area under the receiver operating characteristic curve: 0.81, 95% confidence interval [CI] 0.77-0.85) and good calibration (Hosmer-Lemeshow test, P = 0.794) for identifying NASH. In the 2 validation cohorts, the nomogram showed high area under the receiver operating characteristic curves (internal validation set: 0.80, 95% CI 0.72-0.88; external validation cohort: 0.76, 95% CI 0.72-0.80) and good calibration.

DISCUSSION

Our newly developed and externally validated nomogram, incorporating both genetic and clinical risk factors, may be conveniently used to predict NASH. Further validation studies in other ethnic groups are warranted to confirm its diagnostic utility to identify NASH, among patients with biopsy-proven NAFLD.

Assessment of Lifestyle Factors Helps to Identify Liver Fibrosis Due to Non-Alcoholic Fatty Liver Disease in Obesity

Only some individuals with obesity develop liver fibrosis due to non-alcoholic fatty liver disease (NAFLD-fibrosis). We determined whether detailed assessment of lifestyle factors in addition to physical, biochemical and genetic factors helps in identification of these patients. A total of 100 patients with obesity (mean BMI 40.0 ± 0.6 kg/m²) referred for bariatric surgery at the Helsinki University Hospital underwent a liver biopsy to evaluate liver histology. Physical activity was determined by accelerometer recordings and by the Modifiable Activity Questionnaire, diet by the FINRISK Food Frequency Questionnaire, and other lifestyle factors, such as sleep patterns and smoking, by face-to-face interviews. Physical and biochemical parameters and genetic risk score (GRS based on variants in PNPLA3, TM6SF2, MBOAT7 and HSD17B13) were measured. Of all participants 49% had NAFLD-fibrosis. Independent predictors of NAFLD-fibrosis were low moderate-to-vigorous physical activity, high red meat intake, low carbohydrate intake, smoking, HbA_1c, triglycerides and GRS. A model including these factors (areas under the receiver operating characteristics curve (AUROC) 0.90 (95% CI 0.84–0.96)) identified NAFLD-fibrosis significantly more accurately than a model including all but lifestyle factors (AUROC 0.82 (95% CI 0.73–0.91)) or models including lifestyle, physical and biochemical, or genetic factors alone. Assessment of lifestyle parameters in addition to physical, biochemical and genetic factors helps to identify obese patients with NAFLD-fibrosis.

rs641738C>T near MBOAT7 is associated with liver fat, ALT and fibrosis in NAFLD: A meta-analysis

BACKGROUND & AIMS

A common genetic variant near MBOAT7 (rs641738C>T) has been previously associated with hepatic fat and advanced histology in NAFLD; however, these findings have not been consistently replicated in the literature. We aimed to establish whether rs641738C>T is a risk factor across the spectrum of NAFLD and to characterise its role in the regulation of related metabolic phenotypes through a meta-analysis.

METHODS

We performed a meta-analysis of studies with data on the association between rs641738C>T genotype and liver fat, NAFLD histology, and serum alanine aminotransferase (ALT), lipids or insulin. These included directly genotyped studies and population-level data from genome-wide association studies (GWAS). We performed a random effects meta-analysis using recessive, additive and dominant genetic models.

RESULTS

Data from 1,066,175 participants (9,688 with liver biopsies) across 42 studies were included in the meta-analysis. rs641738C>T was associated with higher liver fat on CT/MRI (+0.03 standard deviations [95% CI 0.02-0.05], pz = 4.8×10-5) and diagnosis of NAFLD (odds ratio [OR] 1.17 [95% CI 1.05-1.3], pz = 0.003) in Caucasian adults. The variant was also positively associated with presence of advanced fibrosis (OR 1.22 [95% CI 1.03-1.45], pz = 0.021) in Caucasian adults using a recessive model of inheritance (CC + CT vs. TT). Meta-analysis of data from previous GWAS found the variant to be associated with higher ALT (pz = 0.002) and lower serum triglycerides (pz = 1.5×10-4). rs641738C>T was not associated with fasting insulin and no effect was observed in children with NAFLD.

CONCLUSIONS

Our study validates rs641738C>T near MBOAT7 as a risk factor for the presence and severity of NAFLD in individuals of European descent.

LAY SUMMARY

Fatty liver disease is a common condition where fat builds up in the liver, which can cause liver inflammation and scarring (including 'cirrhosis'). It is closely linked to obesity and diabetes, but some genes are also thought to be important. We did this study to see whether one specific change ('variant') in one gene ('MBOAT7') was linked to fatty liver disease. We took data from over 40 published studies and found that this variant near MBOAT7 is linked to more severe fatty liver disease. This means that drugs designed to work on MBOAT7 could be useful for treating fatty liver disease.

Genetic and epigenetic factors determining NAFLD risk

BACKGROUND

Hepatic steatosis is a common chronic liver disease that can progress into more severe stages of NAFLD or promote the development of life-threatening secondary diseases for some of those affected. These include the liver itself (nonalcoholic steatohepatitis or NASH; fibrosis and cirrhosis, and hepatocellular carcinoma) or other organs such as the vessels and the heart (cardiovascular disease) or the islets of Langerhans (type 2 diabetes). In addition to elevated caloric intake and a sedentary lifestyle, genetic and epigenetic predisposition contribute to the development of NAFLD and the secondary diseases.

SCOPE OF REVIEW

We present data from genome-wide association studies (GWAS) and functional studies in rodents which describe polymorphisms identified in genes relevant for the disease as well as changes caused by altered DNA methylation and gene regulation via specific miRNAs. The review also provides information on the current status of the use of genetic and epigenetic factors as risk markers.

MAJOR CONCLUSION

With our overview we provide an insight into the genetic and epigenetic landscape of NAFLD and argue about the applicability of currently defined risk scores for risk stratification and conclude that further efforts are needed to make the scores more usable and meaningful.

The role of omics in the pathophysiology, diagnosis and treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a multifaceted metabolic disorder, whose spectrum covers clinical, histological and pathophysiological developments ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and liver fibrosis, potentially evolving into cirrhosis, hepatocellular carcinoma and liver failure. Liver biopsy remains the gold standard for diagnosing NAFLD, while there are no specific treatments. An ever-increasing number of high-throughput Omics investigations on the molecular pathobiology of NAFLD at the cellular, tissue and system levels produce comprehensive biochemical patient snapshots. In the clinical setting, these applications are considerably enhancing our efforts towards obtaining a holistic insight on NAFLD pathophysiology. Omics are also generating non-invasive diagnostic modalities for the distinct stages of NAFLD, that remain though to be validated in multiple, large, heterogenous and independent cohorts, both cross-sectionally as well as prospectively. Finally, they aid in developing novel therapies. By tracing the flow of information from genomics to epigenomics, transcriptomics, proteomics, metabolomics, lipidomics and glycomics, the chief contributions of these techniques in understanding, diagnosing and treating NAFLD are summarized herein.

Genetic predisposition in metabolic-dysfunction-associated fatty liver disease and cardiovascular outcomes-Systematic review

BACKGROUND

Despite the demonstrated increased cardiovascular (CV) risk associated with metabolic-dysfunction-associated fatty liver disease (MAFLD), genetic variants predisposing to MAFLD were not constantly associated with CV events. Recently, rs641738C > T near membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) has been studied in MAFLD and CV outcomes. Therefore, we aimed to evaluate the association between rs641738C > T in the presence and severity of hepatic steatosis, fibrosis, biochemical markers and progression to hepatocellular carcinoma (HCC), in addition to CV outcomes in MAFLD.

MATERIALS AND METHODS

An electronic search on PubMed, Embase and Cochrane Library for articles published till 23 March 2020 was systematically performed. Articles were screened, and data extracted from eligible studies by two reviewers independently.

RESULTS

Studies conducted on adults with MAFLD involving European, Hispanic and African American populations evaluating rs641738 reported reduced hepatic expression of MBOAT7, increased hepatic fat content, severity of MAFLD, susceptibility to develop NASH, advanced fibrosis and HCC in adults. However, most articles involving Asian individuals contradicted these findings. Studies involving obese children associated rs641738 with increased plasma alanine aminotransferase (ALT) levels, while its association with MAFLD remains inconsistent. The rs641738 variant was assessed as a MAFLD susceptibility gene in coronary artery disease (CAD) reporting neutral effects.

CONCLUSIONS

Despite inconclusive results in Asian populations, rs641738C > T near MBOAT7 is associated with increased hepatic fat, MAFLD severity, susceptibility to develop NASH, advanced fibrosis and HCC in adults from Caucasian, Hispanic and African American ethnicities with MAFLD, as well as elevated ALT levels in children, while exerting neutral effects in CAD.

Need to establish a new adolescent suicide prevention programme in South Korea

Adolescent suicide is the leading cause of death among South Korean (Korean) youth. Despite great efforts being made towards suicide prevention in Korea, the suicide rate has not decreased significantly. There is an urgent need for a new adolescent suicide prevention strategy. This paper describes the seriousness of the issue of adolescent suicide in Korea, evaluates its current management by the SWOT analysis (strengths, weaknesses, opportunities and threats) and further recommends a new suicide prevention programme that integrates national/social involvement (State Suicide Intervention Committee, suicide posts’ monitoring, parental divorce information sharing and Adolescence Mental Health Promotion Foundation), school-based programmes (continuous monitoring system, psychology consultation team and mental health educational curricula) and family-based programmes (parental education and family-school communication). In addition, genetic analysis, biochemical tests and psychological disease registration are the indispensable elements that aid in suicidal behaviour prevention and prediction.