Risk estimation model for nonalcoholic fatty liver disease in the Japanese using multiple genetic markers

Clinical Utility of Genetic Variants in PNPLA3 and TM6SF2 to Predict Liver-Related Events in Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND AND AIMS

Fibrosis-4 (FIB-4) index and genetic polymorphisms have been used in assessing the risk of liver-related events (LRE) in metabolic dysfunction-associated steatotic liver disease (MASLD). To establish a more efficient prediction strategy for LRE, we investigated a combined approach that uses the FIB-4 index and genetic polymorphisms.

METHODS

We enrolled 1304 Japanese patients with biopsy-proven MASLD in this longitudinal multicenter cohort study. PNPLA3, TM6SF2, GCKR and MBOAT7 genotypes were genotyped, and polygenic risk score high fat content (PRS-HFC) were calculated.

RESULTS

During the follow-up period of 8.1 year, 96 LRE occurred and 53 patients died. PNPLA3, TM6SF2 and GCKR genotypes were associated with LRE development. We divided patients into three groups based on the FIB-4 index and PNPLA3 and TM6SF2 genotype. The cumulative LRE development rate in each group was 2.1%/28.9%/53.5%, respectively, at 10 years. Multivariate analysis revealed hazard ratios (HRs) for LRE of 10.72 in the high-risk group and 4.80 in the intermediate-risk group. Overall survival in each group was 98.8%/85.2%/72.4%, respectively, at 10 years. HRs for prognosis were 8.74 in the high-risk group and 5.62 in the intermediate-risk group. Patients with FIB-4 index > 2.67 and high PRS-HFC had HR of 6.70 for LRE development and HR of 6.07 for prognosis compared to patients with FIB-4 ≤ 2.67.

CONCLUSIONS

The approach of measuring the FIB-4 index first followed by assessment of genetic polymorphisms efficiently detected patients at high risk of developing LRE. Therefore, this two-step strategy could be used as a screening method in large populations of patients with MASLD.

Role of genetic variants and DNA methylation of lipid metabolism-related genes in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), is one of the most common chronic liver diseases, which encompasses a spectrum of diseases, from metabolic dysfunction-associated steatotic liver (MASL) to metabolic dysfunction-associated steatohepatitis (MASH), and may ultimately progress to MASH-related cirrhosis and hepatocellular carcinoma (HCC). MASLD is a complex disease that is influenced by genetic and environmental factors. Dysregulation of hepatic lipid metabolism plays a crucial role in the development and progression of MASLD. Therefore, the focus of this review is to discuss the links between the genetic variants and DNA methylation of lipid metabolism-related genes and MASLD pathogenesis. We first summarize the interplay between MASLD and the disturbance of hepatic lipid metabolism. Next, we focus on reviewing the role of hepatic lipid related gene loci in the onset and progression of MASLD. We summarize the existing literature around the single nucleotide polymorphisms (SNPs) associated with MASLD identified by genome-wide association studies (GWAS) and candidate gene analyses. Moreover, based on recent evidence from human and animal studies, we further discussed the regulatory function and associated mechanisms of changes in DNA methylation levels in the occurrence and progression of MASLD, with a particular emphasis on its regulatory role of lipid metabolism-related genes in MASLD and MASH. Furthermore, we review the alterations of hepatic DNA and blood DNA methylation levels associated with lipid metabolism-related genes in MASLD and MASH patients. Finally, we introduce potential value of the genetic variants and DNA methylation profiles of lipid metabolism-related genes in developing novel prognostic biomarkers and therapeutic targets for MASLD, intending to provide references for the future studies of MASLD.

Genetic Risk Factors for Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), is the most common cause of liver disease, and its burden on health systems worldwide continues to rise at an alarming rate. MASLD is a complex disease in which the interactions between susceptible genes and the environment influence the disease phenotype and severity. Advances in human genetics over the past few decades have provided new opportunities to improve our understanding of the multiple pathways involved in the pathogenesis of MASLD. Notably, the PNPLA3, TM6SF2, GCKR, MBOAT7 and HSD17B13 single nucleotide polymorphisms have been demonstrated to be robustly associated with MASLD development and disease progression. These genetic variants play crucial roles in lipid droplet remodeling, secretion of hepatic very low-density lipoprotein and lipogenesis, and understanding the biology has brought new insights to this field. This review discusses the current body of knowledge regarding these genetic drivers and how they can lead to development of MASLD, the complex interplay with metabolic factors such as obesity, and how this information has translated clinically into the development of risk prediction models and possible treatment targets.

[Molecular Mechanisms by Which Polyunsaturated Fatty Acids Suppress the Pathogenesis and Progression of NAFLD]

In recent years, the number of people suffering from lifestyle diseases such as hyperlipidemia and fatty liver disease has increased rapidly due to westernization of dietary patterns. Among fatty liver diseases, those that are not caused by alcohol are referred to as nonalcoholic fatty liver disease (NAFLD). Some NAFLD can progress to nonalcoholic steatohepatitis (NASH), and further progression of NAFLD can lead to cirrhosis and liver cancer. Although numerous studies have demonstrated the efficacy of dietary polyunsaturated fatty acids (PUFAs), particularly omega-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), against NAFLD, the detailed mechanisms by which these PUFAs exert their protective effects on the pathogenesis and progression of NAFLD are not well understood. Recent studies using knockout mouse models and genome-wide association studies have suggested a potential role for the enzymes responsible for the biosynthesis of PUFAs (FADS1, FADS2, ELOVL2, and ELOVL5) and their incorporation into phospholipids (LPCAT3/MBOAT5/LPLAT12 and LPIAT1/MBOAT7/LPLAT11) in the development of NAFLD. In this review, we summarize recent findings on the association of NAFLD and PUFAs with a focus on PUFA biosynthetic and metabolic enzymes to discuss the potential role of PUFAs in the prevention of NAFLD.

A 4-year cohort study of the effects of PNPLA3 rs738409 genotypes on liver fat and fibrosis and gut microbiota in a non-fatty liver population

BACKGROUND

Many factors are associated with the development and progression of liver fat and fibrosis; however, genetics and the gut microbiota are representative factors. Moreover, recent studies have indicated a link between host genes and the gut microbiota. This study investigated the effect of patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 (C > G), which has been reported to be most involved in the onset and progression of fatty liver, on liver fat and fibrosis in a cohort study related to gut microbiota in a non-fatty liver population.

METHODS

This cohort study included 214 participants from the health check-up project in 2018 and 2022 who had non-fatty liver with controlled attenuation parameter (CAP) values <248 dB/m by FibroScan and were non-drinkers. Changes in CAP values and liver stiffness measurement (LSM), liver-related items, and gut microbiota from 2018 to 2022 were investigated separately for PNPLA3 rs738409 CC, CG, and GG genotypes.

RESULTS

Baseline values showed no difference among the PNPLA3 rs738409 genotypes for any of the measurement items. From 2018 to 2022, the PNPLA3 rs738409 CG and GG genotype groups showed a significant increase in CAP and body mass index; no significant change was observed in the CC genotype group. LSM increased in all genotypes, but the rate of increase was highest in the GG genotype, followed by the CG and CC genotypes. Fasting blood glucose levels increased in all genotypes; however, HOMA-IR (Homeostasis Model Assessment of Insulin Resistance) increased significantly only in the GG genotype. HDL (high-density lipoprotein) and LDL (low-density lipoprotein) cholesterol levels significantly increased in all genotypes, whereas triglycerides did not show any significant changes in any genotype. As for the gut microbiota, the relative abundance of Feacalibacterium in the PNPLA3 rs738409 GG genotype decreased by 2% over 4 years, more than 2-fold compared to CC and GG genotypes. Blautia increased significantly in the CC group.

CONCLUSION

The results suggest that PNPLA3 G-allele carriers of non-fatty liver develop liver fat and fibrosis due to not only obesity and insulin resistance but also the deterioration of gut microbiota, which may require a relatively long course of time, even years.

Transcriptome-Wide Association Study of Metabolic Dysfunction-Associated Steatotic Liver Disease Identifies Relevant Gene Signatures

Metabolic dysfunction-associated steatotic liver disease (MASLD) is considered the most widespread chronic liver condition globally. Genome-wide association studies (GWAS) have pinpointed several genetic loci correlated to MASLD, yet the biological significance of these loci remains poorly understood. Initially, we applied Functional Mapping and Annotation (FUMA) to conduct a functional annotation of the MASLD GWAS summary statistics, which included data from 3242 cases and 707 631 controls. Additionally, a MASLD transcriptome association study (TWAS) was conducted utilizing FUSION software in combination with the genotype-tissue expression project (GTEx-v8) expression weight set to identify susceptibility genes. Furthermore, to elucidate the observed correlations, we carried out conditional and joint analyses, probabilistic causal fine-mapping of TWAS signals, summary data-based Mendelian randomization (SMR), and phenome-wide association analyses. Following functional annotation analysis, we identified 4 genetic risk loci, annotated 6 lead single nucleotide polymorphisms (SNPs), 27 independent significant SNPs, and 511 candidate SNPs. TWAS also found four genes related to MASLD, including MAU2 sister chromatid cohesion factor (MAU2), EPH receptor A2 (EPHA2), GATA zinc finger domain containing 2A (GATAD2A), and transmembrane 6 superfamily member 2 (TM6SF2). Moreover, fine mapping of TWAS signatures identified 13 causal genes associated with MASLD that were located at 3 genetic risk loci, but SMR results could not rule out the possibility that the relationship between significant genes and MASLD was caused by a linkage disequilibrium structure. Our study found new significantly associated genes for MASLD and highlighted the ability of TWAS to identify and prioritize potentially pathogenic genes.

An epidemiological study on the factors including genetic polymorphism influencing ALT >30 U/L and liver fibrosis progression in metabolic dysfunction-associated steatotic liver disease among the general population

Background and Aim

Identifying the factors contributing to the progression of metabolic dysfunction-associated steatotic liver disease (MASLD), a lifestyle-related disease, is crucial for preventing future liver-related deaths. This study aimed to epidemiologically investigate factors, including single-nucleotide polymorphisms (SNPs) associated with alanine aminotransferase (ALT) levels >30 U/L and potential risk factors for liver fibrosis, in a general population cohort of patients with MASLD.

Methods

Among 1059 participants in the health checkup project, 228 who were diagnosed with MASLD were analyzed. Liver fat content and stiffness were measured using FibroScan, and 13 SNPs associated with non-alcoholic fatty liver disease (NAFLD) were measured in addition to other clinical parameters.

Results

In the multivariate analysis, male sex, younger age, and high triglyceride levels were significant risk factors for ALT levels >30 U/L (P-value < 0.05). Furthermore, among the 13 SNPs measured, only the GG genotypes of patatin-like phospholipase domain-containing 3 gene (PNPLA3) rs738409 and rs2896019 were significant risk factors for ALT levels >30 U/L (P-value 0.004 and 0.007). The GG genotypes of PNPLA3 rs738409 and rs2896019 had higher FibroScan-aspartate aminotransferase (FAST) and APRI scores than the CC + CG and TT + TG genotypes (P-value < 0.05). In addition, multivariate analysis revealed that the GG genotypes of rs738409 and rs2896019 were significant risk factors independent of cardiovascular metabolic risk for patients with MASLD (P-value 0.038 and 0.021).

Conclusion

An individualized treatment approach is warranted for patients with MASLD due to the influence of various factors on its progression, including genetic factors and lifestyle diseases.

Epidemiology, pathophysiology and clinical aspects of Hepatocellular Carcinoma in MAFLD patients

Hepatocellular carcinoma (HCC) is undergoing a transformative shift, with metabolic-associated fatty liver disease (MAFLD) emerging as a dominant etiology. Diagnostic criteria for MAFLD involve hepatic steatosis and metabolic dysregulation. Globally, MAFLD prevalence stands at 38.77%, significantly linked to the escalating rates of obesity. Epidemiological data indicate a dynamic shift in the major etiologies of hepatocellular carcinoma (HCC), transitioning from viral to metabolic liver diseases. Besides the degree of liver fibrosis, several modifiable lifestyle risk factors, such as type 2 diabetes, obesity, alcohol use, smoking, and HBV, HCV infection contribute to the pathogenesis of HCC. Moreover  gut microbiota and genetic variants may contribute to HCC development.The pathophysiological link between MAFLD and HCC involves metabolic dysregulation, impairing glucose and lipid metabolism, inflammation and oxidative stress. Silent presentation poses challenges in early MAFLD-HCC diagnosis. Imaging, biopsy, and AI-assisted techniques aid diagnosis, while HCC surveillance in non-cirrhotic MAFLD patients remains debated.ITA.LI.CA. group proposes a survival-based algorithm for treatment based on Barcelona clinic liver cancer (BCLC) algorithm. Liver resection, transplantation, ablation, and locoregional therapies are applied based on the disease stage. Systemic treatments is promising, with initial immunotherapy results indicating a less favorable response in MAFLD-related HCC.Adopting lifestyle interventions and chemopreventive measures with medications, including aspirin, metformin, and statins, constitute promising approaches for the primary prevention of HCC.Prognosis is influenced by multiple factors, with MAFLD-HCC associated with prolonged survival. Emerging diagnostic biomarkers and epigenomic markers, show promising results for early HCC detection in the MAFLD population.

Epidemiological Study on the Interaction between the PNPLA3 (rs738409) and Gut Microbiota in Metabolic Dysfunction-Associated Steatotic Liver Disease

Many factors are associated with the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD); however, genetics and gut microbiota are representative factors. Recent studies have highlighted the link between host genes and the gut microbiota. Although there have been many studies on the separate effects of single nucleotide polymorphisms (SNPs) and gut bacteria on MASLD, few epidemiological studies have examined how SNPs and gut bacteria interact in the development and progression of MASLD. This study aimed to investigate the association between PNPLA3 rs738409, a representative MASLD-related SNP, and gut bacteria in MASLD using a cross-sectional study of the general population. The 526 participants (318 normal and 208 MASLD groups) were grouped into the PNPLA3 rs738409 SNP, CC, CG, and GG genotypes, and the differences in the gut microbiota were investigated in each group. The PNPLA3 rs738409 CC and CG genotypes were associated with decreased Blautia and Ruminococcaceae in the MASLD group. They were negatively correlated with controlled attenuation parameter levels, body mass index, serum blood glucose, and triglycerides. In contrast, there was no association between the normal and MASLD groups and the gut bacteria in the PNPLA3 rs738409, the GG genotype group. This finding implies that dietary interventions and probiotics may be more effective in preventing and treating MASLD in individuals with the PNPLA3 rs738409 CC and CG genotypes. In contrast, their efficacy may be limited in those with the GG genotype.

Healthy Lifestyle and the Risk of Metabolic Dysfunction-Associated Fatty Liver Disease: A Large Prospective Cohort Study

BACKGRUOUND

The incidence density of metabolic dysfunction-associated fatty liver disease (MAFLD) and the effect of a healthy lifestyle on the risk of MAFLD remain unknown. We evaluated the prevalence and incidence density of MAFLD and investigated the association between healthy lifestyle and the risk of MAFLD.

METHODS

A cross-sectional analysis was conducted on 37,422 participants to explore the prevalence of MAFLD. A cohort analysis of 18,964 individuals was conducted to identify the incidence of MAFLD, as well as the association between healthy lifestyle and MAFLD. Cox proportional hazards regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) with adjustments for confounding factors.

RESULTS

The prevalence of MAFLD, non-alcoholic fatty liver disease, and their comorbidities were 30.38%, 28.09%, and 26.13%, respectively. After approximately 70 thousand person-years of follow-up, the incidence densities of the three conditions were 61.03, 55.49, and 51.64 per 1,000 person-years, respectively. Adherence to an overall healthy lifestyle was associated with a 19% decreased risk of MAFLD (HR, 0.81; 95% CI, 0.72 to 0.92), and the effects were modified by baseline age, sex, and body mass index (BMI). Subgroup analyses revealed that younger participants, men, and those with a lower BMI experienced more significant beneficial effects from healthy lifestyle.

CONCLUSION

Our results highlight the beneficial effect of adherence to a healthy lifestyle on the prevention of MAFLD. Health management for improving dietary intake, physical activity, and smoking and drinking habits are critical to improving MAFLD.

Metabolic Dysfunction-Associated Steatotic Liver Disease in Japan: Prevalence Trends and Clinical Background in the 10 Years before the Coronavirus Disease 2019 Pandemic

Background and Objectives: The trends in metabolic dysfunction-associated steatotic liver disease (MASLD) and related metabolic dysfunctions in Japan are unknown. Thus, we aimed to clarify these trends before the novel coronavirus disease 2019 pandemic in Japan. Materials and Methods: We included Japanese individuals aged 25-79 years who underwent health examinations at our center. We analyzed anthropometry, lifestyle-related disease, and nutritional intake in relation to MASLD trends from 2010-2019. Results: The prevalence of MASLD increased in all ages and body mass index (BMI) classes, reaching 30.3% in males and 16.1% in females, with MASLD accounting for 75% of steatotic liver cases and more than half of all type 2 diabetes mellitus (T2DM) and high waist circumference (HWC) cases. The increase in the prevalence of MASLD was thought to be largely attributable to an increase in that of the incidence of steatotic liver itself, and there was no increase in the prevalence of other factors, such as overweight, T2DM, hypertension, and dyslipidemia. The prevalence of glucose metabolic disorders (GMDs) and hypertension decreased. National nutritional data showed an increase in energy intake, total fat, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids, which correlated with a decrease in GMDs. Salt intake also decreased, which correlated with hypertension. The MASLD group had a higher prevalence of all related metabolic factors than the non-MASLD group, especially HWC, T2DM, and hyperlipidemia. Conclusions: The prevalence of MASLD increased with that of steatotic liver, regardless of age or BMI. A relationship between increased dietary fat, increased steatotic liver, and decreased GMDs was suggested.

The interaction of genetics and physical activity in the pathogenesis of metabolic dysfunction associated liver disease

Genetic variants associated with increased liver fat and volume have been reported, but whether physical activity (PA) can attenuate the impact of genetic susceptibility to these traits is poorly understood. We aimed to investigate whether higher PA modify genetic impact on liver-related traits in the UK Biobank cohort. PA was self-reported, while magnetic resonance images were used to estimate liver fat (n = 27,243) and liver volume (n = 24,752). Metabolic dysfunction-associated liver disease (MASLD) and chronic liver disease (CLD) were diagnosed using ICD-9 and ICD-10 codes. Ten liver fat and eleven liver volume-associated genetic variants were selected and unweighted genetic-risk scores for liver fat (GRSLF) and liver volume (GRSLV) were computed. Linear regression analyses were performed to explore interactions between GRSLF/ GRSLV and PA in relation to liver-related traits. Association between GRSLF and liver fat was not different among lower (β = 0.063, 95% CI 0.041-0.084) versus higher PA individuals (β = 0.065, 95% CI 0.054-0.077, pinteraction = 0.62). The association between the GRSLV and liver volume was not different across different PA groups (pinteraction = 0.71). Similarly, PA did not modify the effect of GRSLF and GRSLV on MASLD or CLD. Our findings show that physical activity and genetic susceptibility to liver-related phenotypes seem to act independently, benefiting all individuals regardless of genetic risk.

Genotypic variation in CYP2E1, GCKR, and PNPLA3 among nonalcoholic steatohepatitis patients of Turkish origin

BACKGROUND

This study examines genetic variations in CYP2E1 (rs6413432, rs3813867), GCKR (rs780094, rs1260326), and PNPLA3 (rs738409) among Turkish patients to assess their influence on nonalcoholic steatohepatitis.

METHODS

Allele and genotype frequencies were compared between 245 NASH patients and 120 healthy controls using SNP genotyping via polymerase chain reaction-restriction fragment length polymorphism. Additionally, the deviation of the observed genotype frequencies from Hardy-Weinberg proportion was examined.

RESULTS

No significant differences were found in the allelic and genotypic distributions of rs6413432, rs3813867, and rs780094 between NASH patients and healthy controls. However, significant disparities were noted for rs1260326 and rs738409. Gender and age-specific distributions showed no notable differences. The only observed deviation from Hardy-Weinberg proportion was in the genotype frequency of rs738409.

CONCLUSIONS

Variants in GCKR (rs1260326) and PNPLA3 (rs738409) are significantly associated with increased NASH risk in the Turkish population, with the rs738409 variant potentially playing a more prominent role in NASH development.

Clinical and genetic risk factors for progressive fibrosis in metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Fibrosis-4 (FIB4) is a recommended noninvasive test to assess hepatic fibrosis among patients with metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we used FIB4 trajectory over time (ie, "slope" of FIB4) as a surrogate marker of liver fibrosis progression and examined if FIB4 slope is associated with clinical and genetic factors among individuals with clinically defined MASLD within the Million Veteran Program Cohort.

METHODS

In this retrospective cohort study, FIB4 slopes were estimated through linear regression for participants with clinically defined MASLD and FIB4 <2.67 at baseline. FIB4 slope was correlated with demographic parameters and clinical outcomes using logistic regression and Cox proportional hazard models. FIB4 slope as a quantitative phenotype was used in a genome-wide association analysis in ancestry-specific analysis and multiancestry meta-analysis using METAL.

RESULTS

FIB4 slopes, generated from 98,361 subjects with MASLD (16,045 African, 74,320 European, and 7996 Hispanic), showed significant associations with sex, ancestry, and cardiometabolic risk factors (p < 0.05). FIB4 slopes also correlated strongly with hepatic outcomes and were independently associated with time to cirrhosis. Five genetic loci showed genome-wide significant associations (p < 5 × 10-8) with FIB4 slope among European ancestry subjects, including 2 known (PNPLA3 and TM6SF2) and 3 novel loci (TERT 5.1 × 10-11; LINC01088, 3.9 × 10-8; and MRC1, 2.9 × 10-9).

CONCLUSIONS

Linear trajectories of FIB4 correlated significantly with time to progression to cirrhosis, with liver-related outcomes among individuals with MASLD and with known and novel genetic loci. FIB4 slope may be useful as a surrogate measure of fibrosis progression.

Molecular Genealogy of Metabolic-associated Hepatocellular Carcinoma

This review examines the latest epidemiological and molecular pathogenic findings of metabolic-associated hepatocellular carcinoma (HCC). Its increasing prevalence is a significant concern and reflects the growing burden of obesity and metabolic diseases, including metabolic dysfunction-associated steatotic liver disease, formerly known as nonalcoholic fatty liver disease, and type 2 diabetes. Metabolic-associated HCC has unique molecular abnormality and distinctive gene expression patterns implicating aberrations in bile acid, fatty acid metabolism, oxidative stress, and proinflammatory pathways. Furthermore, a notable frequency of single nucleotide polymorphisms in genes such as patatin-like phospholipase domain-containing 3, transmembrane 6 superfamily member 2, glucokinase regulator, and membrane-bound O-acyltransferase domain-containing 7 has been observed. The tumor immune microenvironment of metabolic-associated HCC is characterized by unique phenotypes of macrophages, neutrophils, and T lymphocytes. Additionally, the pathogenesis of metabolic-associated HCC is influenced by abnormal lipid metabolism, insulin resistance, and dysbiosis. In conclusion, deciphering the intricate interactions among metabolic processes, genetic predispositions, inflammatory responses, immune regulation, and microbial ecology is imperative for the development of novel therapeutic and preventative measures against metabolic-associated HCC.

Genome-wide association study of metabolic dysfunction-associated fatty liver disease in a Korean population

Genome-wide association studies have identified several genetic variants associated with nonalcoholic fatty liver disease. To emphasize metabolic abnormalities in fatty liver, metabolic (dysfunction)-associated fatty liver disease (MAFLD) has been introduced; thus, we aimed to investigate single-nucleotide polymorphisms related to MAFLD and its subtypes. A genome-wide association study was performed to identify genetic factors related to MAFLD. We used a Korean population-based sample of 2282 subjects with MAFLD and a control group of 4669. We replicated the results in a validation sample which included 639 patients with MAFLD and 1578 controls. Additionally, we categorized participants into three groups, no MAFLD, metabolic dysfunction (MD)-MAFLD, and overweight/obese-MAFLD. After adjusting for age, sex, and principal component scores, rs738409 [risk allele G] and rs3810622 [risk allele T], located in the PNPLA3 gene, showed significant associations with MAFLD (P-values, discovery set = 1.60 × 10-15 and 4.84 × 10-10; odds ratios, 1.365 and 1.284, validation set = 1.39 × 10-4, and 7.15 × 10-4, odds ratios, 1.299 and 1.264, respectively). An additional SNP rs59148799 [risk allele G] located in the GATAD2A gene showed a significant association with MAFLD (P-values, discovery set = 2.08 × 10-8 and validation set = 0.034, odds ratios, 1.387 and 1.250). rs738409 was significantly associated with MAFLD subtypes ([overweight/obese-MAFLD; odds ratio (95% confidence interval), P-values, 1.515 (1.351-1.700), 1.43 × 10-12 and MD-MAFLD: 1.300 (1.191-1.416), 2.90 × 10-9]. There was a significant relationship between rs3810622 and overweight/obese-MAFLD and MD-MAFLD [odds ratios (95% confidence interval), P-values, 1.418 (1.258, 1.600), 1.21 × 10-8 and 1.225 (1.122, 1.340), 7.06 × 10-6, respectively]; the statistical significance remained in the validation set. PNPLA3 was significantly associated with MAFLD and MAFLD subtypes in the Korean population. These results indicate that genetic factors play an important role in the pathogenesis of MAFLD.

Hepatocellular and extrahepatic cancer risk in people with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Much of the recognised health-care burden occurs in the minority of people with NAFLD who progress towards cirrhosis and require specialist follow-up, including risk stratification and hepatocellular carcinoma surveillance. NAFLD is projected to become the leading global cause of cirrhosis and hepatocellular carcinoma, but the frequency of non-cirrhotic hepatocellular carcinoma provides a challenge to existing surveillance strategies. Deaths from extrahepatic cancers far exceed those from hepatocellular carcinoma in NAFLD. Unlike hepatocellular carcinoma, the increased extrahepatic cancer risk in NAFLD is not dependent on liver fibrosis stage. Given that almost 30% of the world's adult population has NAFLD, extrahepatic cancer could represent a substantial health and economic issue. In this Review, we discuss current knowledge and controversies regarding hepatocellular carcinoma risk stratification and surveillance practices in people with NAFLD. We also assess the associations of extrahepatic cancers with NAFLD and their relevance both in the clinic and the wider community.

Germline Genetic Associations for Hepatobiliary Cancers

Hepatobiliary cancers (HBCs) include hepatocellular carcinoma, cholangiocarcinoma, and gallbladder carcinoma, which originate from the liver, bile ducts, and gallbladder, respectively. They are responsible for a substantial burden of cancer-related deaths worldwide. Despite knowledge of risk factors and advancements in therapeutics and surgical interventions, the prognosis for most patients with HBC remains bleak. There is evidence from familial aggregation and case-control studies to suggest a familial risk component in HBC susceptibility. Recent progress in genomics research has led to the identification of germline variants including single nucleotide polymorphisms (SNPs) and pathogenic or likely pathogenic (P/LP) variants in cancer-associated genes associated with HBC risk. These findings emerged from genome-wide association studies and next-generation sequencing techniques such as whole-exome sequencing. Patients with other cancer types, including breast, colon, ovarian, prostate, and pancreatic cancer, are recommended by guidelines to undergo germline genetic testing, but similar recommendations are lagging in HBC. This prompts the question of whether multi-gene panel testing should be integrated into clinical guidelines for HBC management. Here, we review the hereditary genetics of HBC, explore studies investigating SNPs and P/LP variants in HBC patients, discuss the clinical implications and potential for personalized treatments and impact on patient's family members, and conclude that additional studies are needed to examine how genetic testing can be applied clinically.

Artificial intelligence/neural network system that accurately diagnoses hepatocellular carcinoma in nonalcoholic steatohepatitis

BACKGROUND AND AIM

The aim of this study was to develop a novel noninvasive test using an artificial intelligence/neural network system (called HCC-Scope) to diagnose early-stage hepatocellular carcinoma (HCC) on the background of nonalcoholic steatohepatitis (NASH).

METHODS

In total, 175 patients with histologically proven nonalcoholic fatty liver disease and 55 patients with NASH-HCC were enrolled for training and validation studies. Of the 55 patients with NASH-HCC, 27 (49.1%) had very early-stage HCC, and six (10.9%) had early-stage HCC based on the Barcelona Clinic Liver Cancer staging system. Diagnosis with HCC-Scope was performed based on 12 items: age, sex, height, weight, AST level, ALT level, gamma-glutamyl transferase level, cholesterol level, triglyceride level, platelet count, diabetes status, and IgM-free apoptosis inhibitor of macrophage level. The FMVWG2U47 hardware (Fujitsu Co. Ltd, Tokyo, Japan) and the originally developed software were used.

RESULTS

HCC-Scope had sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100% for the differential diagnosis between non-HCC and HCC in a training study with gray zone analysis. It was also excellent in the validation study (95.0% sensitivity, 100% specificity, 100% PPV, and 97.1% NPV with gray zone analysis and 95.2% sensitivity, 100% specificity, 100% PPV, and 97.1% NPV without gray zone analysis). HCC-Scope had a significantly higher sensitivity (85.3%) and specificity (85.1%) than alpha-fetoprotein (AFP) level, AFP-L3 level, des-gamma-carboxy prothrombin (DCP) level, and the gender-age-AFP-L3-AFP-DCP (GALAD) score.

CONCLUSIONS

HCC-Scope can accurately differentially diagnose between non-HCC NASH and NASH-HCC, including very early-stage NASH-HCC.

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.

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.

Advances in Noninvasive Biomarkers for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) currently represents one of the most common liver diseases worldwide. Early diagnosis and disease staging is crucial, since it is mainly asymptomatic, but can progress to nonalcoholic steatohepatitis (NASH) or cirrhosis or even lead to the development of hepatocellular carcinoma. Over time, efforts have been put into developing noninvasive diagnostic and staging methods in order to replace the use of a liver biopsy. The noninvasive methods used include imaging techniques that measure liver stiffness and biological markers, with a focus on serum biomarkers. Due to the impressive complexity of the NAFLD's pathophysiology, biomarkers are able to assay different processes involved, such as apoptosis, fibrogenesis, and inflammation, or even address the genetic background and "omics" technologies. This article reviews not only the currently validated noninvasive methods to investigate NAFLD but also the promising results regarding recently discovered biomarkers, including biomarker panels and the combination of the currently validated evaluation methods and serum markers.

MAFLD: an optimal framework for understanding liver cancer phenotypes

Hepatocellular carcinoma has a substantial global mortality burden which is rising despite advancements in tackling the traditional viral risk factors. Metabolic (dysfunction) associated fatty liver disease (MAFLD) is the most prevalent liver disease, increasing in parallel with the epidemics of obesity, diabetes and systemic metabolic dysregulation. MAFLD is a major factor behind this sustained rise in HCC incidence, both as a single disease entity and often via synergistic interactions with other liver diseases. Mechanisms behind MAFLD-related HCC are complex but is crucially underpinned by systemic metabolic dysregulation with variable contributions from interacting disease modifiers related to environment, genetics, dysbiosis and immune dysregulation. MAFLD-related HCC has a distinct clinical presentation, most notably its common occurrence in non-cirrhotic liver disease. This is just one of several major challenges to effective surveillance programmes. The response of MAFLD-related HCC to immune-checkpoint therapy is currently controversial, and is further complicated by the high prevalence of MAFLD in individuals with HCC from viral aetiologies. In this review, we highlight the current data on epidemiology, clinical characteristics, outcomes and screening controversies. In addition, concepts that have arisen because of the MAFLD paradigm such as HCC in MAFLD/NAFLD non-overlapping groups, dual aetiology tumours and MAFLD sub-phenotypes is reviewed.

The emerging significance of mitochondrial targeted strategies in NAFLD treatment

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide, ranging from liver steatosis to nonalcoholic steatohepatitis, which ultimately progresses to fibrosis, cirrhosis, and hepatocellular carcinoma. Individuals with NAFLD have a higher risk of developing cardiovascular and extrahepatic cancers. Despite the great progress being made in understanding the pathogenesis and the introduction of new pharmacological targets for NAFLD, no drug or intervention has been accepted for its management. Recent evidence suggests that NAFLD may be a mitochondrial disease, as mitochondrial dysfunction is involved in the pathological processes that lead to NAFLD. In this review, we describe the recent advances in our understanding of the mechanisms associated with mitochondrial dysfunction in NAFLD progression. Moreover, we discuss recent advances in the efficacy of mitochondria-targeted compounds (e.g., Mito-Q, MitoVit-E, MitoTEMPO, SS-31, mitochondrial uncouplers, and mitochondrial pyruvate carrier inhibitors) for treating NAFLD. Furthermore, we present some medications currently being tested in clinical trials for NAFLD treatment, such as exercise, mesenchymal stem cells, bile acids and their analogs, and antidiabetic drugs, with a focus on their efficacy in improving mitochondrial function. Based on this evidence, further investigations into the development of mitochondria-based agents may provide new and promising alternatives for NAFLD management.

Glucokinase regulatory protein: a balancing act between glucose and lipid metabolism in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease worldwide, affected by both genetics and environment. Type 2 diabetes (T2D) stands as an independent environmental risk factor that precipitates the onset of hepatic steatosis and accelerates its progression to severe stages of liver damage. Furthermore, the coexistence of T2D and NAFLD magnifies the risk of cardiovascular disease synergistically. However, the association between genetic susceptibility and metabolic risk factors in NAFLD remains incompletely understood. The glucokinase regulator gene (GCKR), responsible for encoding the glucokinase regulatory protein (GKRP), acts as a regulator and protector of the glucose-metabolizing enzyme glucokinase (GK) in the liver. Two common variants (rs1260326 and rs780094) within the GCKR gene have been associated with a lower risk for T2D but a higher risk for NAFLD. Recent studies underscore that T2D presence significantly amplifies the effect of the GCKR gene, thereby increasing the risk of NASH and fibrosis in NAFLD patients. In this review, we focus on the critical roles of GKRP in T2D and NAFLD, drawing upon insights from genetic and biological studies. Notably, prior attempts at drug development targeting GK with glucokinase activators (GKAs) have shown potential risks of augmented plasma triglycerides or NAFLD. Conversely, overexpression of GKRP in diabetic rats improved glucose tolerance without causing NAFLD, suggesting the crucial regulatory role of GKRP in maintaining hepatic glucose and lipid metabolism balance. Collectively, this review sheds new light on the complex interaction between genes and environment in NAFLD, focusing on the GCKR gene. By integrating evidence from genetics, biology, and drug development, we reassess the therapeutic potential of targeting GK or GKRP for metabolic disease treatment. Emerging evidence suggests that selectively activating GK or enhancing GK-GKRP binding may represent a holistic strategy for restoring glucose and lipid metabolic balance.

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.

Dysregulated peripheral proteome reveals NASH-specific signatures identifying patient subgroups with distinct liver biology

Background and aims

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. The prognosis may vary from simple steatosis to more severe outcomes such as nonalcoholic steatohepatitis (NASH), liver cirrhosis, and hepatocellular carcinoma. The understanding of the biological processes leading to NASH is limited and non-invasive diagnostic tools are lacking.

Methods

The peripheral immunoproteome in biopsy-proven NAFL (n=35) and NASH patients (n=35) compared to matched, normal-weight healthy controls (n=15) was studied using a proximity extension assay, combined with spatial and single cell hepatic transcriptome analysis.

Results

We identified 13 inflammatory serum proteins that, independent of comorbidities and fibrosis stage, distinguished NASH from NAFL. Analysis of co-expression patterns and biological networks further revealed NASH-specific biological perturbations indicative of temporal dysregulation of IL-4/-13, -10, -18, and non-canonical NF-kβ signaling. Of the identified inflammatory serum proteins, IL-18 and EN-RAGE as well as ST1A1 mapped to hepatic macrophages and periportal hepatocytes, respectively, at the single cell level. The signature of inflammatory serum proteins further permitted identification of biologically distinct subgroups of NASH patients.

Conclusion

NASH patients have a distinct inflammatory serum protein signature, which can be mapped to the liver parenchyma, disease pathogenesis, and identifies subgroups of NASH patients with altered liver biology.

Genetic Markers Predisposing to Nonalcoholic Steatohepatitis

The growing prevalence of nonalcoholic fatty liver disease (NAFLD) has sparked interest in understanding genetics and epigenetics associated with the development and progression of the disease. A better understanding of the genetic factors related to progression will be beneficial in the risk stratification of patients. These genetic markers can also serve as potential therapeutic targets in the future. In this review, we focus on the genetic markers associated with the progression and severity of NAFLD.

Nonalcoholic steatohepatitis-related hepatocellular carcinoma: pathogenesis and treatment

Nonalcoholic fatty liver disease (NAFLD), including its more severe manifestation, nonalcoholic steatohepatitis (NASH), has a global prevalence of 20-25% and is a major public health problem. Its incidence is increasing in parallel to the rise in obesity, diabetes and metabolic syndrome. Progression from NASH to NASH-related hepatocellular carcinoma (HCC) (~2% of cases per year) is influenced by many factors, including the tissue and immune microenvironment, germline mutations in PNPLA3, and the microbiome. NASH-HCC has unique molecular and immune traits compared with other aetiologies of HCC and is equally prevalent in men and women. Comorbidities associated with NASH, such as obesity and diabetes mellitus, can prevent the implementation of potentially curative therapies in certain patients; nonetheless, outcomes are similar in patients who receive treatment. NASH-HCC at the early to intermediate stages is managed with surgery and locoregional therapies, whereas advanced HCC is treated with systemic therapies, including anti-angiogenic therapies and immune-checkpoint inhibitors. In this Review, we present the latest knowledge of the pathogenic mechanisms and clinical management of NASH-HCC. We discuss data highlighting the controversy over varying responses to immune-checkpoint inhibitors according to underlying aetiology and suggest that the future of NASH-HCC management lies in improved surveillance, targeted combination therapies to overcome immune evasion, and identifying biomarkers to recognize treatment responders.

Genetic Susceptibility to Hepatocellular Carcinoma in Patients with Chronic Hepatitis Virus Infection

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. The risk factors for HCC include chronic hepatitis B and C virus infections, excessive alcohol consumption, obesity, metabolic disease, and aflatoxin exposure. In addition to these viral and environmental risk factors, individual genetic predisposition is a major determinant of HCC risk. Familial clustering of HCC has been observed, and a hereditary factor likely contributes to the risk of HCC development. The familial aggregation may depend on a shared environment and genetic background as well as the interactions of environmental and genetic factors. Genome-wide association studies (GWASs) are one of the most practical tools for mapping the patterns of inheritance for the most common form of genomic variation, single nucleotide polymorphisms. This approach is practical for investigating genetic variants across the human genome, which is affected by thousands of common genetic variants that do not follow Mendelian inheritance. This review article summarizes the academic knowledge of GWAS-identified genetic loci and their association with HCC. We summarize the GWASs in accordance with various chronic hepatitis virus infection statuses. This genetic profiling could be used to identify candidate biomarkers to refine HCC screening and management by enabling individual risk-based personalization and stratification. A more comprehensive understanding of the genetic mechanisms underlying individual predisposition to HCC may lead to improvements in the prevention and early diagnosis of HCC and the development of effective treatment strategies.

Clinical Outcomes in Biopsy-Proven Nonalcoholic Fatty Liver Disease Patients: A Multicenter Registry-based Cohort Study

BACKGROUND & AIMS

There are no detailed reports of clinical outcomes in Asian patients with nonalcoholic fatty liver disease (NAFLD) who undergo liver biopsy. We aimed to investigate the clinical outcomes of a large cohort of Asian patients with biopsy-proven NAFLD and evaluate the specific effects of nonalcoholic steatohepatitis and fibrosis stage.

METHODS

This multicenter registry-based retrospective cohort study, called the CLIONE (Clinical Outcome Nonalcoholic Fatty Liver Disease) in Asia, included 1398 patients.

RESULTS

The median follow-up period was 4.6 years (range, 0.3-21.6 years), representing a total of 8874 person-years of follow-up. During that time, 47 patients died, and 1 patient underwent orthotopic liver transplantation. The leading cause of death was nonhepatic cancer (n = 10). The leading causes of liver-related death were liver failure (n = 9), hepatocellular carcinoma (HCC) (n = 8), and cholangiocellular carcinoma (n = 4). During follow-up, 37 patients developed HCC, 31 developed cardiovascular disease, and 68 developed nonhepatic cancer (mainly breast, stomach, and colon/rectum). Among our cohort of patients with NAFLD, liver-specific mortality was 2.34/1000 person-years (95% confidence interval [CI], 1.52-3.58), overall mortality was 5.34/1000 person-years (95% CI, 4.02-7.08), and HCC incidence was 4.17/1000 person-years (95% CI, 3.02-5.75). Liver fibrosis was independently associated with liver-related events but not overall mortality.

CONCLUSIONS

Liver-related mortality was the leading cause of mortality in Asian patients with biopsy-confirmed NAFLD. Although fibrosis stage was independently associated with liver-related events, it was not associated with overall mortality after adjusting for confounders, such as histologic features of steatohepatitis.

Perspectives on the Underlying Etiology of HCC and Its Effects on Treatment Outcomes

Hepatocellular carcinoma (HCC) continues to be a serious medical problem with poor prognosis worldwide. The distribution of the major etiologies of HCC is changing due to the progress of anti-viral treatments, including hepatitis B virus (HBV) suppression by nucleoside/nucleotide analogues (NAs) and increased sustained virologic response (SVR) rates by direct-acting antivirals (DAAs) for hepatitis C virus (HCV), as well as the rising trend of nonviral liver disease. Although viral hepatitis remains the most common cause of HCC, non-alcoholic liver disease (NAFLD) with metabolic syndrome and alcohol-associated liver disease (ALD) are increasing. Effective and well-tolerated NAs treatment can slow the disease progression of chronic HBV infection to cirrhosis, end-stage liver disease, and reduce HCC risk. Treatment with NAs is also associated with significant improvement in the long-term survival of patients with HBV infection who already have HCC. DAAs have achieved viral elimination in almost all patients with HCV without significant adverse events, even in patients with decompensated liver cirrhosis and HCC. Similarly, DAA therapy can reduce disease progression, liver and non-liver complications, and improve the long-term survival of patients with chronic HCV infection with or without HCC. Meanwhile, NAFLD is a rapidly increasing cause of HCC along with the epidemics of obesity and type 2 diabetes globally. NAFLD-related HCC can occur in patients without cirrhosis and is known to have a lower survival rate than viral hepatitis-related HCC. Since there is currently no specific pharmacotherapy effective for NAFLD, lifestyle modification and prevention of complications are important to improve prognosis. Additionally, ALD is the second fastest-growing cause of HCC-related deaths, especially with an accelerated trend since the COVID-19 pandemic. This review provides an overview of the epidemiologic trends in the etiologies of HCC, and the progress of treatments for each etiology and the impact on outcome in the patients with HCC.

NAFLD-related hepatocellular carcinoma: The growing challenge

Hepatocellular carcinoma (HCC) is a common cause of cancer-related mortality and morbidity worldwide. With the obesity pandemic, NAFLD-related HCC is contributing to the burden of disease exponentially. Genetic predisposition and clinical risk factors for NAFLD-related HCC have been identified. Cirrhosis is a well-known and major risk factor for NAFLD-related HCC. However, the occurrence of NAFLD-related HCC in patients without cirrhosis is increasingly recognized and poses a significant challenge regarding cancer surveillance. It is of paramount importance to develop optimal risk stratification scores and models to identify subsets of the population at high risk so they can be enrolled in surveillance programs. In this review, we will discuss the risks and prediction models for NAFLD-related HCC.

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.

The FIB-4 Index Predicts the Development of Liver-Related Events, Extrahepatic Cancers, and Coronary Vascular Disease in Patients with NAFLD

The prognosis of nonalcoholic fatty liver disease (NAFLD) patients depends on liver-related events (LREs), extrahepatic cancers, and major adverse cardiovascular events (MACEs). The fibrosis-4 (FIB-4) index is one of the most reliable and useful predictors of the degree of liver fibrosis. Recent studies have reported that the FIB-4 index is also useful for predicting LREs and MACEs in NAFLD patients. In the present study, we investigated the prognostic value of the FIB-4 index in NAFLD patients. A total of 506 biopsy-confirmed NAFLD patients from six hepatology centers in Japan from 2002 to 2013 were enrolled in this study. Of these NAFLD patients, 353 were available for more than 100 days of follow-up and did not exhibit events (LREs, extrahepatic cancers, MACEs) at the time of entry. The mean follow-up duration of all the subjects was 2716 ± 1621 days (102-7483 days). New LREs (hepatocellular carcinoma (HCC) (n = 8), decompensation (n = 11), bleeding varices (n = 8)) developed in 18 patients. Twenty-four and twelve patients developed extrahepatic cancers and MACEs, respectively. The median FIB-4 index was 1.255; we divided our cohort into two groups according to this (FIB4 Low, FIB4 Hi). The incidence of HCC tended to be higher in FIB4 Hi (n = 7) than in FIB4 Low (n = 1). The incidence of LREs was significantly higher in FIB4 Hi (n = 17) than in FIB4 Low (n = 1). The incidence of extrahepatic cancers was significantly higher in FIB4 Hi (n = 20) than in FIB4 Low (n = 4); the incidence of MACEs was also significantly higher in FIB4 Hi (n = 10) than in FIB4 Low (n = 2). The FIB-4 index is a useful biomarker for predicting not only LREs but also extrahepatic cancers and MACEs.

Epidemiologic, Genetic, Pathogenic, Metabolic, Epigenetic Aspects Involved in NASH-HCC: Current Therapeutic Strategies

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the sixth most frequent cancer in the world, being the third cause of cancer-related deaths. Nonalcoholic steatohepatitis (NASH) is characterized by fatty infiltration, oxidative stress and necroinflammation of the liver, with or without fibrosis, which can progress to advanced liver fibrosis, cirrhosis and HCC. Obesity, metabolic syndrome, insulin resistance, and diabetes exacerbates the course of NASH, which elevate the risk of HCC. The growing prevalence of obesity are related with increasing incidence of NASH, which may play a growing role in HCC epidemiology worldwide. In addition, HCC initiation and progression is driven by reprogramming of metabolism, which indicates growing appreciation of metabolism in the pathogenesis of this disease. Although no specific preventive pharmacological treatments have recommended for NASH, dietary restriction and exercise are recommended. This review focuses on the molecular connections between HCC and NASH, including genetic and risk factors, highlighting the metabolic reprogramming and aberrant epigenetic alterations in the development of HCC in NASH. Current therapeutic aspects of NASH/HCC are also reviewed.

Serum levels of immunoglobulin M-free inhibitors of macrophage/CD5L as a predictive and early diagnostic marker for nonalcoholic steatohepatitis-associated hepatocellular carcinoma

BACKGROUND

The apoptosis inhibitor of macrophage (AIM) is usually associated with the immunoglobulin M (IgM) pentamer in the blood and is dissociated from IgM in various diseases, including hepatocellular carcinoma (HCC) in nonalcoholic steatohepatitis (NASH). We aimed to elucidate whether IgM-free AIM (fAIM) is useful for detecting latent HCC in NASH.

METHODS

This research consisted of two cohort studies. The levels of serum fAIM, alpha-fetoprotein (AFP), and des-gamma carboxy prothrombin (DCP) of 18 NASH patients who developed HCC were measured during the follow-up period before HCC diagnosis (median, 4.7 years). In total, 199 patients with nonalcoholic fatty liver disease (NAFLD) were included in the HCC survey. The serum fAIM levels were analyzed using enzyme-linked immunosorbent assays.

RESULTS

In the cohort of 18 patients with HCC, 12 had high fAIM at the time of the initial blood sample, three had normal fAIM levels throughout the follow-up period, and three had fAIM elevated from normal to positive. The positive ratio of fAIM prior to HCC diagnosis remained significantly higher than that of AFP and DCP, and the fAIM ratio gradually increased. In a survey of 199 non-HCC NAFLD patients, a Cox regression analysis using independent variables, such as AFP, fAIM, age, albumin, bilirubin, and fibrosis stage, revealed that fAIM and AFP were significantly associated with the incidence of HCC.

CONCLUSIONS

During the development of NASH-HCC, AIM activation in blood appears to start even before HCC is diagnostically detectable. Thus, the serum IgM-free AIM levels could be a new, sensitive biomarker for latent NASH-HCC.

The link between liver fat and cardiometabolic diseases is highlighted by genome-wide association study of MRI-derived measures of body composition

Obesity and associated morbidities, metabolic associated fatty liver disease (MAFLD) included, constitute some of the largest public health threats worldwide. Body composition and related risk factors are known to be heritable and identification of their genetic determinants may aid in the development of better prevention and treatment strategies. Recently, large-scale whole-body MRI data has become available, providing more specific measures of body composition than anthropometrics such as body mass index. Here, we aimed to elucidate the genetic architecture of body composition, by conducting genome-wide association studies (GWAS) of these MRI-derived measures. We ran both univariate and multivariate GWAS on fourteen MRI-derived measurements of adipose and muscle tissue distribution, derived from scans from 33,588 White European UK Biobank participants (mean age of 64.5 years, 51.4% female). Through multivariate analysis, we discovered 100 loci with distributed effects across the body composition measures and 241 significant genes primarily involved in immune system functioning. Liver fat stood out, with a highly discoverable and oligogenic architecture and the strongest genetic associations. Comparison with 21 common cardiometabolic traits revealed both shared and specific genetic influences, with higher mean heritability for the MRI measures (h2 = .25 vs. .13, p = 1.8x10-7). We found substantial genetic correlations between the body composition measures and a range of cardiometabolic diseases, with the strongest correlation between liver fat and type 2 diabetes (rg = .49, p = 2.7x10-22). These findings show that MRI-derived body composition measures complement conventional body anthropometrics and other biomarkers of cardiometabolic health, highlighting the central role of liver fat, and improving our knowledge of the genetic architecture of body composition and related diseases.

African genetic ancestry is associated with lower frequency of PNPLA3 G allele in non-alcoholic fatty liver in an admixed population

INTRODUCTION AND OBJECTIVES

PNPLA3 (rs738409) and TM6SF2 (rs58542926) variants, interindividual and ethnic differences may be risk factors for non-alcoholic fatty liver disease (NAFLD). The PNPLA3 G allele is associated with worse NAFLD evolution in Hispanics and Caucasians. TM6SF2 is associated with hypertriglyceridemia, NAFLD, and cardiovascular disease. We aimed to evaluate the association between genetic ancestry by Ancestry Informative Markers (AIM), PNPLA3 and TM6SF2 polymorphisms in patients with biopsy-proven NAFLD in an admixed population.

METHODS

We included adults with biopsy-proven NAFLD and excluded patients with the presence of other chronic liver disease, alcohol intake >100g/week, HIV, drug-induced fatty liver disease, or liver transplantation. We classified NAFLD using the Non-Alcoholic Steatohepatitis Clinical Research Network (NASH-CRN) histological scoring system. The PNPLA3 (rs738409 c.444C>G) and TM6SF2 (rs58542926 c.449C>T) genotyping were performed by RT-PCR. Genetic ancestry was determined using 46 insertion-deletion AIM; α<0.05 was considered significant.

RESULTS

A total of 248 patients with NAFLD were enrolled [34 with simple steatosis (NAFL); 214 with NASH]. Overall, we detected a greater European ancestry contribution (0.645), followed by African (0.173), Amerindian (0.095), and East Asian (0.087) ancestry contribution, without differences between NAFL and NASH patients. However, we found a higher African genetic ancestry contribution among patients with NAFL who had the PNPLA3 C/C genotype than those with the G allele (0.216 ± 0.205 versus 0.105 ± 0.101, respectively; p=0.047). Ancestry contributions did not differ among TM6SF2 genotypes.

CONCLUSION

Among NAFL patients, greater African genetic ancestry was associated to a lower frequency of the PNPLA3 G allele, demonstrating a possible NASH ancestry-related protective factor.

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.

RISK FACTORS FOR HEPATOCELLULAR CARCINOMA IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE

Non-alcoholic fatty liver disease is growing in worldwide prevalence and thus, is expected to have a higher number of NAFLD-related hepatocellular carcinoma (HCC) in the following years. This review describes the risk factors associated with HCC in NAFLD-patients. The presence of liver cirrhosis is the preponderant one. Male gender, PNPLA3 variants, diabetes, and obesity also appear to predispose to the development of HCC, even in non-cirrhotic subjects. Thus far, intensive lifestyle modifications, including glycemic control, and obesity treatment, are effective therapies for NAFLD/ non-alcoholic steatohepatitis and, therefore, probably, also for HCC. Some drugs that aimed at decreasing inflammatory activity and fibrosis, as well as obesity, were studied. Other data have suggested the possibility of HCC chemoprevention. So far, however, there is no definitive evidence for the routine utilization of these drugs. We hope, in the future, to be able to profile patients at higher risk of NAFLD-HCC and outline strategies for early diagnosis and prevention.

NAFLD polygenic risk score and risk of hepatocellular carcinoma in an East Asian population

It is difficult to identify people with nonalcoholic fatty liver disease (NAFLD) who are at high risk for developing hepatocellular carcinoma (HCC). A polygenic risk score (PRS) for hepatic fat (HFC-PRS) derived from non-Asians has been reported to be associated with HCC risk in European populations. However, population-level data of this risk in Asian populations are lacking. Utilizing resources from 24,333 participants of the Singapore Chinese Health Study (SCHS), we examined the relationship between the HFC-PRS and HCC risk. In addition, we constructed and evaluated a NAFLD-related PRS (NAFLD-PRS) with HCC risk in the SCHS. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of HCC incidence with both HFC-PRS and NAFLD-PRS. The HFC-PRS and NAFLD-PRS were highly correlated (Spearman r = 0.79, p < 0.001). The highest quartiles of both the HFC-PRS and the NAFLD-PRS were associated with significantly increased risk of HCC with HR of 2.39 (95% CI 1.51, 3.78) and 1.77 (95% CI 1.15, 2.73), respectively, compared with their respective lowest quartile. Conclusion: The PRS for hepatic fat content or NAFLD may be useful for assessing HCC risk in both Asian and European populations. The findings of this and prior studies support a potential causal role of genetically determined NAFLD in HCC development.

Characterization of Nutrient Intake in Biopsy-Confirmed NAFLD Patients

Objectives: Weight loss improves the liver pathophysiological status of nonalcoholic fatty liver disease (NAFLD) patients. However, there are few studies that investigate the accurate relationships between nutritional intake and disease progression in NAFLD patients. Methods: A total of 37 biopsy-confirmed NAFLD patients were enrolled in this study. Clinical and nutritional control data of 5074 persons were obtained from the National Institute of Health and Nutrition. Each NAFLD subject recorded dietary intake for seven consecutive days using a dietary questionnaire and photographs of each meal. A dietitian analyzed and quantified the nutritional data in each patient. We further analyzed the nutritional intake of NAFLD patients in three groups according to the following criteria: (1) liver fibrosis degree (advanced, early), (2) gender (male, female), and (3) body mass index (BMI) (high, low). Results: Excesses or deficiencies of multiple nutrients were found in NAFLD patients compared with control subjects. In addition, there were variations in nutritional intake. (1) The intake of vitamins A, B₆, and E, pantothenic acid, soluble dietary fiber, and salt was lower in the advanced fibrosis group than in the early fibrosis group. (2) Fat intake was higher in male patients, and dietary fiber intake was lower in both male and female patients compared with control subjects. (3) Saturated fatty acid intake was higher, and copper and vitamin E intakes were lower in patients with high BMI than with low BMI. Conclusions: Our study demonstrates that differences were found in some nutrient intake of NAFLD patients and controls and according to the severity of the conditions (liver fibrosis degree, BMI).

Genetic variants associated with metabolic dysfunction-associated fatty liver disease in western China

INTRODUCTION

We aimed to confirm the association between some single nucleotide polymorphisms (SNPs) and metabolic dysfunction-associated fatty liver disease (MAFLD) in western China.

METHODS

A total of 286 cases and 250 healthy controls were enrolled in our study. All samples were genotyped for patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, membrane-bound O-acyltransferase domain containing 7 (MBOAT7) rs641738, glucokinase regulator (GCKR) rs1260326 and rs780094, and GATA zinc finger domain containing 2A (GATAD2A) rs4808199. Using logistic regression analysis, we evaluated the association between MAFLD and each SNP under different models. Multiple linear regression was used to find the association between SNPs and laboratory characteristics. Multifactor dimensionality reduction was applied to test SNP-SNP interactions.

RESULTS

The recessive model and additive model of PNPLA3 rs738409 variant were related to MAFLD (odds ratio [OR] = 1.791 and 1.377, respectively, p = 0.038 and 0.027, respectively). However, after Benjamini-Hochberg adjustment for multiple tests, all associations were no longer statistically significant. PNPLA3 rs738409 correlated with AST levels. GCKR rs780094 and rs1260326 negatively correlated with serum glucose but positively correlated with triglycerides in MAFLD. Based on MDR analysis, the best single-locus and multilocus models for MAFLD risk were rs738409 and six-locus models, respectively.

CONCLUSIONS

In the Han population in western China, no association was found between these SNPs and the risk of MAFLD. PNPLA3 rs738409 was associated with aspartate aminotransferase levels in MAFLD patients. GCKR variants were associated with increased triglyceride levels and reduced serum fasting glucose in patients with MAFLD.

Risk factors and diagnostic biomarkers for nonalcoholic fatty liver disease-associated hepatocellular carcinoma: Current evidence and future perspectives

High rates of excessive calorie intake diets and sedentary lifestyles have led to a global increase in nonalcoholic fatty liver disease (NAFLD). As a result, this condition has recently become one of the leading causes of hepatocellular carcinoma (HCC). Furthermore, the incidence of NAFLD-associated HCC (NAFLD-HCC) is expected to increase in the near future. Advanced liver fibrosis is the most common risk factor for NAFLD-HCC. However, up to 50% of NAFLD-HCC cases develop without underlying liver cirrhosis. Epidemiological studies have revealed many other risk factors for this condition; including diabetes, other metabolic traits, obesity, old age, male sex, Hispanic ethnicity, mild alcohol intake, and elevated liver enzymes. Specific gene variants, such as single-nucleotide polymorphisms of patatin-like phospholipase domain 3, transmembrane 6 superfamily member 2, and membrane-bound O-acyl-transferase domain-containing 7, are also associated with an increased risk of HCC in patients with NAFLD. This clinical and genetic information should be interpreted together for accurate risk prediction. Alpha-fetoprotein (AFP) is the only biomarker currently recommended for HCC screening. However, it is not sufficiently sensitive in addressing this diagnostic challenge. The GALAD score can be calculated based on sex, age, lectin-bound AFP, AFP, and des-carboxyprothrombin and is reported to show better diagnostic performance for HCC. In addition, emerging studies on genetic and epigenetic biomarkers have also yielded promising diagnostic potential. However, further research is needed to establish an effective surveillance program for the early diagnosis of NAFLD-HCC.

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.

Serum Mac-2 binding protein level predicts the development of liver-related events and colorectal cancer in patients with NAFLD

We previously demonstrated that Mac-2 binding protein (M2BP) is a useful biomarker for nonalcoholic fatty liver disease (NAFLD), particularly NAFLD fibrosis prediction. In the present study, we investigated the prognostic value of M2BP in patients with NAFLD. A total of 506 patients with biopsy-confirmed NAFLD from 2002 to 2013 were enrolled in this study in Japan. Three hundred fifty-three of these patients with NAFLD were available for follow-up for more than 100 days and showed no liver-related events at the time of entry. Liver-related events were defined as hepatocellular carcinoma (HCC), decompensation, and gastroesophageal varices with variceal treatment. The mean follow-up duration of all the subjects was 2716 ± 1621 days (102-7483 days). Eighteen patients developed new liver-related events (HCC, 8; decompensation, 11; varices, 8). Nine patients developed cardiovascular disease (CVD), and 24 patients developed new cancers in other organs. The median serum M2BP level was 1.603 μg/mL, and we divided our cohort into two groups according to the serum M2BP level: M2BP low group (M2BP Low) and M2BP high group (M2BP Hi). The incidence of HCC was significantly higher in M2BP Hi (n = 8) than in M2BP Low (n = 0). The incidence of liver-related events was significantly higher in M2BP Hi (n = 16) than in M2BP Low (n = 2). The incidences of death, CVD events, and cancer in other organs were not different between the groups. Interestingly, the incidence of colorectal cancer was significantly higher in M2BP Hi (n = 5) than in M2BP Low (n = 0). Conclusion: M2BP is a useful biomarker to predict liver-related events, particularly HCC. Additionally, M2BP is a potential predictive biomarker of colorectal cancer development.

Update on Non-Alcoholic Fatty Liver Disease-Associated Single Nucleotide Polymorphisms and Their Involvement in Liver Steatosis, Inflammation, and Fibrosis: A Narrative Review

Genetic factors are involved in the development, progression, and severity of non-alcoholic fatty liver disease (NAFLD). Polymorphisms in genes regulating liver functions may increase liver susceptibility to NAFLD. Therefore, we conducted this literature study to present recent findings on NAFLD-associated polymorphisms from published articles in PubMed from 2016 to 2021. From 69 selected research articles, 20 genes and 34 SNPs were reported to be associated with NAFLD. These mutated genes affect NAFLD by promoting liver steatosis (PNPLA3, MBOAT7, TM2SF6, PTPRD, FNDC5, IL-1B, PPARGC1A, UCP2, TCF7L2, SAMM50, IL-6, AGTR1, and NNMT), inflammation (PNPLA3, TNF-α, AGTR1, IL-17A, IL-1B, PTPRD, and GATAD2A), and fibrosis (IL-1B, PNPLA3, MBOAT7, TCF7L2, GATAD2A, IL-6, NNMT, UCP, AGTR1, and TM2SF6). The identification of these genetic factors helps to better understand the pathogenesis pathways of NAFLD.