PNPLA3 Genotype and Diabetes Identify Patients With Nonalcoholic Fatty Liver Disease at High Risk of Incident Cirrhosis

A comprehensive evaluation of candidate genetic polymorphisms in a large histologically characterized MASLD cohort using a novel framework

BACKGROUND

There is a substantial heritable component to metabolic dysfunction-associated steatotic liver disease (MASLD), and several genetic variants that promote MASLD development or associate with its severity have been reported. These associations vary in terms of their effect size and degree of replication.

METHODS

We developed a framework to classify previously identified MASLD genetic polymorphisms into 4 tiers based on effect size and extent of replication in the literature. We tested the association between "tier 1" single-nucleotide polymorphisms (OR ≥1.5, replicated in >2 independent studies) and biopsy measures of MASLD severity in a large, well-characterized histologic cohort of MASLD patients (n=3094).

RESULTS

Across 19 "tier 1" variants reflecting 11 genetic loci, only those in the PNPLA3-SAMM50-PARVB locus showed significant associations with biopsy-proven fibrosis severity and NAFLD activity score; the highest risk was for the rs738409 p.I148M variant in PNPLA3. A genetic risk score based on "tier 1" variants, as well as a previously developed genetic risk score based on variants in PNPLA3, TM6SF2, and HSD17B13, were both associated with fibrosis and NAFLD activity score, but these results were driven entirely by PNPLA3 rs738409.

CONCLUSIONS

Our study provides a framework to prioritize evaluation of genetic polymorphisms for future replication efforts and demonstrates that in a large case-only cohort, histologic severity of MASLD is only robustly associated with the presence of variation in PNPLA3 among known candidate genes. These findings may have implications for patient risk stratification based on the presence of PNPLA3 rs738409.

Development and Validation of Machine Learning-Based Marker for Early Detection and Prognosis Stratification of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease and is considered the hepatic manifestation of metabolic syndrome, triggering out adverse outcomes. A stacked multimodal machine learning model is constructed and validated for early identification and prognosis stratification of NAFLD by integrating genetic and clinical data sourced from 36 490 UK Biobank and 9 007 Nanfang Hospital participants and extracted its probabilities as in-silico scores for NAFLD (ISNLD). The efficacy of ISNLD is evaluated for the early prediction of severe liver disease (SeLD) and analyzed its association with metabolism-related outcomes. The multimodal model performs satisfactorily in classifying individuals into low- and high-risk groups for NAFLD, achieving area under curves (AUCs) of 0.843, 0.840, and 0.872 within training, internal, and external test sets, respectively. Among high-risk group, ISNLD is significantly associated with intrahepatic and metabolism-related complications after lifestyle factors adjustment. Further, ISNLD demonstrates notable capability for early prediction of SeLD and further stratifies high-risk subjects into three risk subgroups of elevated risk for adverse outcomes. The findings emphasize the model's ability to integrate multimodal features to generate ISNLD, enabling early detection and prognostic prediction of NAFLD. This facilitates personalized stratification for NAFLD and metabolism-related outcomes based on digital non-invasive markers, enabling preventive interventions.

High inherited risk predicts age-associated increases in fibrosis in patients with MASLD

BACKGROUND & AIMS

Limited data have prevented routine genetic testing from being integrated into clinical practice in metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to quantify the effect of genetic variants on changes in fibrosis severity per decade in MASLD.

METHODS

This cross-sectional study included prospectively recruited adults with MASLD aged 18-70 who underwent magnetic resonance elastography (MRE) and genotyping for PNPLA3, TM6SF2, MBOAT7, GCKR, and HSD17B13. A genetic risk score (GRS) was calculated as the sum of established risk alleles in PNPLA3 minus protective variants in HSD17B13 (0=low risk, 1=high risk). We also estimated the polygenic risk score-hepatic fat content (PRS-HFC) and the adjusted version (PRS-5). The primary endpoint was the age-related change in liver stiffness measurement (LSM) on MRE by GRS. Findings were validated using an external cohort from Latin America.

RESULTS

Among 570 participants, the median age was 57 [49-64] years, 56.8% were women, and 34.2% were Hispanic. Median MRE was 2.4 [2.1-3.0] kPa, and 51% had high GRS. High GRS was independently associated with increased LSM (β=0.28 kPa, 95%CI:0.12-0.44, p=0.001) per 10-year age increase, while the low GRS group showed no significant difference. Similar findings were observed using PRS-HFC and PRS-5. PNPLA3 genotype alone also predicted higher LSM (C/G: β=0.32 kPa, 95%CI:0.02-0.61, p=0.034; G/G: β=0.87 kPa, 95%CI:0.52-1.22, p<0.0001) and G/G genotype was associated with significantly higher LSM by age 44, which was consistent in the validation population.

CONCLUSION

GRS, PRS-HFC, PRS-5, and PNPLA3 genotypes alone are associated with greater fibrosis per decade, resulting in divergent disease trajectories starting in midlife. Assessing genetic risk in MASLD will identify high-risk patients who require more frequent monitoring.

IMPACT AND IMPLICATIONS

This study provides granular evidence that genetic predisposition, particularly the PNPLA3 G/G genotype, significantly influences the trajectory of liver fibrosis in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), with a more pronounced impact emerging after the fourth decade of life. These findings highlight the importance of incorporating genetic risk assessment into MASLD management, as it allows for the early identification of high-risk individuals who may benefit from more frequent monitoring and targeted interventions. Given the rising global burden of MASLD, clinicians, researchers, and policymakers should consider integrating genetic stratification into existing risk assessment frameworks to refine screening and surveillance strategies. By optimizing patient selection for non-invasive fibrosis assessment and potential therapeutic interventions, this approach could enhance precision medicine efforts and may improve long-term outcomes.

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.

Rurality and Neighborhood Socioeconomic Status are Associated With Overall and Cause-Specific Mortality and Hepatic Decompensation in Type 2 Diabetes

INTRODUCTION

Social determinants of health are key factors driving disease progression. In type 2 diabetes there is limited literature on how distal or intermediate factors (eg, those at the neighborhood level) influence cause-specific mortality or liver disease outcomes.

METHODS

This was a single-center retrospective study of patients with type 2 diabetes seen at an integrated healthcare system in the United States. The primary outcomes were overall mortality; death due to cardiovascular disease, cancer, or liver disease; or hepatic decompensation. The primary predictors were neighborhood-level (intermediate) factors measuring neighborhood poverty (Area Deprivation Index [ADI], affluence score, disadvantage score) and rurality (Rural-Urban Commuting Area scores). Associations were modeled using Cox proportional hazards or Fine-Grey competing risk models.

RESULTS

28,424 participants were included. Higher neighborhood poverty associated with increased overall mortality, with hazard ratio (HR) 1.11 (95% confidence interval 1.10-1.12, P < .001) per 10 points of ADI and HR 1.32 (95% CI 1.26-1.37, P < .001) for 10 points of disadvantage. Conversely, higher neighborhood affluence associated with lower overall mortality with HR 0.87 (95% CI 0.86-0.89, P < .001) per 10 points of affluence. Living in a rural region associated with increased overall mortality: HR 1.08 (95% CI 1.01-1.15, P = .031). Associations were consistent across cause-specific mortality, though effect sizes were larger for liver-related mortality than for other causes. Living in a more rural neighborhood was associated with increased risk of hepatic decompensation.

CONCLUSIONS

Intermediate neighborhood-level socioeconomic status was associated with overall and cause-specific mortality in type 2 diabetes, with larger effects on liver-related mortality than other causes.

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.

Human genetics of metabolic dysfunction-associated steatotic liver disease: from variants to cause to precision treatment

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by increased hepatic steatosis with cardiometabolic disease and is a leading cause of advanced liver disease. We review here the genetic basis of MASLD. The genetic variants most consistently associated with hepatic steatosis implicate genes involved in lipoprotein input or output, glucose metabolism, adiposity/fat distribution, insulin resistance, or mitochondrial/ER biology. The distinct mechanisms by which these variants promote hepatic steatosis result in distinct effects on cardiometabolic disease that may be best suited to precision medicine. Recent work on gene-environment interactions has shown that genetic risk is not fixed and may be exacerbated or attenuated by modifiable (diet, exercise, alcohol intake) and nonmodifiable environmental risk factors. Some steatosis-associated variants, notably those in patatin-like phospholipase domain-containing 3 (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2), are associated with risk of developing adverse liver-related outcomes and provide information beyond clinical risk stratification tools, especially in individuals at intermediate to high risk for disease. Future work to better characterize disease heterogeneity by combining genetics with clinical risk factors to holistically predict risk and develop therapies based on genetic risk is required.

Non-Alcoholic Fatty Liver Disease (NAFLD) Management in the Community

Non-alcoholic fatty liver disease (NAFLD) has frequently been associated with obesity, type 2 diabetes (T2D), and dyslipidemia, all of which are shared by increased insulin resistance. It has become the most common liver disorder in Korea as well as in developed countries and is therefore associated with an increased health burden of morbidity and mortality. It has an association with T2D, and T2D increases the risk of cirrhosis and related complications. NAFLD encompasses a disease continuum from simple steatosis to non-alcoholic steatohepatitis which is characterized by faster fibrosis progression. Although its liver-related complication is estimated to be, at most, 10%, it will be a leading cause of cirrhosis and hepatocellular carcinoma soon in Korea. Although the main causes of death in people with NAFLD are cardiovascular disease and extra-hepatic malignancy, advanced liver fibrosis is a key prognostic marker for liver-related outcomes and can be assessed with combinations of non-invasive tests in the community. A number of components of metabolic syndrome involved could be another important prognostic information of NAFLD assessed easily in the routine care of the community. There is a few approved therapies for NAFLD, although several drugs, including antioxidants, attract practitioners' attention. Because of the modest effect of the present therapeutics, let alone complex pathophysiology and substantial heterogeneity of disease phenotypes, combination treatment is a viable option for many patients with NAFLD in the Korean community. Comprehensive approach taking healthy lifestyle and weight reduction into account remain a mainstay to the prevention and treatment of NAFLD.

Physical activity, diet, and social determinants of health associate with health related quality of life and fibrosis in MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading cause of end-stage liver disease. MASLD and liver fibrosis are associated with cardiometabolic risk factors and health-related quality of life (HRQOL) while being affected by dietary/exercise patterns and social determinants of health (SDOH). However, previous studies have not assessed in conjunction exercise, diet, SDOH, and HRQOL in patients with MASLD. This was a cross-sectional study of patients with MASLD seen in hepatology clinic at University of Michigan. Participants completed validated surveys on HRQOL, diet, and physical activity, and a subset also underwent vibration controlled transient elastography (VCTE). The primary outcomes were HRQOL (measured by Short Form-8) and cirrhosis, and predictors were physical activity, dietary patterns, cardiometabolic comorbidities, and social determinants of health. The primary analysis included 304 patients, with median body mass index 32.4 kg/m2 and prevalence of type 2 diabetes, hypertension, and dyslipidemia 38%, 45%, and 42%, respectively (Table 1). The majority of the participants had a FIB-4 score of less than 1.3 and LSM of less than 8 (Table 1). HRQOL was lower with higher BMI, type 2 diabetes, hypertension, and increased liver fibrosis, and higher in people with adequate fruit intake. Neighborhood-level SDOH were also associated with HRQOL. Factors associated with cirrhosis or higher liver stiffness measurement by VCTE included body mass index, diabetes, and living in an impoverished neighborhood, while increased vegetable intake and exercise were associated with lower prevalence of cirrhosis/fibrosis. In multivariable models including demographic and cardiometabolic factors, dietary patterns and SDOH were independently associated with HRQOL and cirrhosis. Cardiometabolic risk factors, physical activity, diet, and social determinants of health are associated with HRQOL and liver fibrosis.

Impact of PNPLA3 I148M on Clinical Outcomes in Patients With MASLD

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a heterogenous clinical and histopathological entity, where multiple metabolic co-factors are intertwined with high interindividual variability. The impact and severity of each factor (including obesity and type 2 diabetes) define a systemic dysmetabolism that can lead to either advanced liver disease and its complication (including hepatocellular carcinoma and clinical events related to portal hypertension) or extrahepatic events: incident cardiovascular disease, chronic kidney disease and extrahepatic cancers. The balance between environmental factors and genetic susceptibility has unique implications in MASLD: the intermittent injury of metabolic co-factors, their fluctuation over time and their specific management, are counterbalanced by the presence of gene variants that can significantly impact the disease at multiple levels. The I148M variant in the PNPLA3 gene is the most investigated genetic susceptibility that induces a more severe steatohepatitis, enhanced fibrogenesis and can shape the incidence of long-term clinical events regardless of, or worsened by, other metabolic risk factors.

METHODS AND RESULTS

In this review, we will summarise the updated evidence on the natural history of MASLD accounting for classical metabolic risk factors, the role of PNPLA3 in clinical sub-phenotyping (e.g., 'lean MASLD'), impact on disease severity and fibrosis progression, as well as its role for prognostication, alone or in combination with non-invasive tools into polygenic risk scores.

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.

Alcohol-Related Liver Disease, Followed by Metabolic Dysfunction-Associated Steatotic Liver Disease, Emerges as the Fastest-Growing Aetiologies for Primary Liver Cancer in the United States

OBJECTIVE

Primary liver cancer (PLC) is projected to be the third leading cause of cancer mortality in the United States in 2040. We examine the burden of PLC in the United States, stratified by sex, state and aetiological risk factors.

METHODS

Data on PLC prevalence, incidence, death and disability-adjusted life years (DALYs) were extracted from the Global Burden of Disease Study 2021. Changes in these parameters were calculated using the Joinpoint regression model.

RESULTS

There were 47,970 cases, 31,450 incident cases, 24,770 deaths and 576,920 DALYs from PLC in the United States. The highest prevalence (16,980), incidence (12,040), death (9840) and DALYs (213,410) from PLC were due to chronic hepatitis C virus infection. From 2000 to 2021, PLC incidences increased by 141%, and PLC deaths increased by 136%. Age-standardised incidence rates (ASIRs) and death rates (ASDRs) per 100,000 population for PLC increased, primarily driven by alcohol-related liver disease (ALD) (ASIR: annual percent change [APC]: +2.40%; ASDR: APC: +2.22%) and metabolic dysfunction-associated steatotic liver disease (MASLD) (ASIR: APC: +2.32%; ASDR: APC: +2.04%).

CONCLUSION

The burden of PLC in the United States has risen in the past two decades, driven mainly by ALD and followed by MASLD. These findings offer policymakers an accurate assessment of the PLC burden and emphasise the need for targeted risk factor mitigation, especially regarding alcohol related policy.

Disparities for Hispanic Adults With Metabolic Dysfunction-associated Steatotic Liver Disease in the United States: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Prevalence and severity of metabolic dysfunction-associated steatotic liver disease (MASLD) is reported to be higher in Hispanic adults in the United States (U.S.), although rates vary substantially across studies and have increased given the evolving obesity epidemic. This systematic review and meta-analysis quantifies MASLD disease burden and severity in contemporary cohorts to characterize health disparities experienced by adult Hispanic individuals in the U.S.

METHODS

We searched the MEDLINE, Embase, and Cochrane databases per the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Studies from 2010 to December 2023 were included to capture data representative of current populations given the obesity epidemic. Studies from overlapping cohorts were excluded. Meta-analyses were conducted using random-effects models to estimate pooled prevalence and relative risk (RR) with 95% confidence intervals (CIs).

RESULTS

We identified 22 studies, comprising 756,088 subjects, of which 62,072 were Hispanic. The pooled prevalence in U.S. Hispanic adults was 41% (95% CI, 30%-52%) for MASLD, 61% (95% CI, 39%-82%) for metabolic dysfunction-associated steatohepatitis (MASH), 27% (95% CI, 15%-39%) for MASH-associated advanced fibrosis (AF), and 5% (95% CI, 1%-8%) for MASH cirrhosis. Compared with non-Hispanic adults, Hispanic adults had a RR of 1.50 (95% CI, 1.32-1.69) for MASLD, 1.42 (95% CI, 1.04-1.93) for MASH, 1.37 (95% CI, 0.96-1.96) for MASH-associated AF, and 0.93 (95% CI, 0.49-1.77) for MASH cirrhosis.

CONCLUSION

Health disparities for U.S. Hispanic adults continue to worsen with significantly higher relative risk of MASLD and MASH compared with non-Hispanic adults. Public health efforts to optimize screening and care delivery for the adult Hispanic population are urgently needed.

LDL-C and TC Mediate the Risk of PNPLA3 Inhibition in Cardiovascular Diseases

CONTEXT

PNPLA3 is a promising target for the treatment of metabolic dysfunction-associated steatotic liver disease. ARO-PNPLA3 is a drug that efficiently lowers PNPLA3 expression in hepatocytes at the mRNA level, resulting in a significant reduction in liver fat in Phase I clinical trials. However, the long-term effects and potential side effects of ARO-PNPLA3 are not well understood.

OBJECTIVE

We conducted a 2-sample, 2-step Mendelian randomization analysis to investigate the association between PNPLA3 inhibition and 10 cardiovascular diseases (CVDs), as well as the role of lipid traits as mediators.

METHODS

We identified genetic variants near the PNPLA3 gene, which are linked to liver fat percentage, as instrumental variables for inhibiting PNPLA3. Additionally, positive control analyses on liver diseases were conducted to validate the selection of the genetic instruments.

RESULTS

Genetically predicted PNPLA3 inhibition significantly increased the risk of coronary atherosclerosis (1.14, 95% CI 1.06, 1.23), coronary heart disease (1.14, 95% CI 1.08, 1.21), and myocardial infarction (1.16, 95% CI 1.08, 1.26). Suggestive associations were observed for increased risk of heart failure (1.09, 95% CI 1.02, 1.17, P = .0143) and atrial fibrillation (1.17, 95% CI 1.00, 1.36, P = .0468). Blood low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) mediated approximately 16% to 25%, 16% to 30%, and 14% to 22% of the associations between PNPLA3 inhibition and coronary atherosclerosis, myocardial infarction, and coronary heart disease, respectively.

CONCLUSION

This study suggests that PNPLA3 inhibition increases the risk of major CVDs. Moreover, blood LDL-C and TC may mediate a significant proportion of the associations between PNPLA3 inhibition and coronary atherosclerosis, coronary heart disease, or myocardial infarction.

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.

Exploring the alleviating effects of Bifidobacterium metabolite lactic acid on non-alcoholic steatohepatitis through the gut-liver axis

Objective

This study investigates the protective effects of lactic acid, a metabolite of Bifidobacterium, on non-alcoholic fatty liver disease (NAFLD) induced by a high-sugar, high-fat diet (HFD) in mice, in the context of the gut-liver axis.

Methods

A NAFLD mouse model was established using a HFD, and different intervention groups were set up to study the protective effects of Bifidobacterium and its metabolite lactic acid. The groups included a control group, NAFLD group, Bifidobacterium treatment group, Glyceraldehyde-3-P (G-3P) co-treatment group, and NOD-like receptor family pyrin domain containing 3 (NLRP3) overexpression group. The evaluation of liver function and lipid metabolism was conducted using the liver-to-body weight ratio, histological staining, and biochemical assays. Enzyme-linked immunosorbent assay (ELISA) was performed to measure inflammatory cytokines, and western blotting was used to analyze the expression of NLRP3 inflammasome and autophagy-related molecules. In vitro, an NAFLD cell model was established using oleic acid, with cells treated with lactic acid and NLRP3 overexpression to assess lipid droplet accumulation and inflammation.

Results

In vivo findings indicated that, in comparison to CBX group (Control group without antibiotic treatment), NAFLD/CBX group (NAFLD group without antibiotic administration) and NAFLD/ABX group (NAFLD group with antibiotic administration) exhibited increased liver-to-body weight ratio, higher lipid droplet accumulation, aggravated liver histopathological damage, and elevated levels of AST (Aspartate Aminotransferase), ALT (Alanine Aminotransferase), TC (Total Cholesterol), TG (Triglycerides), LDL-C (Low-Density Lipoprotein Cholesterol), IL-6 (Interleukin-6), TNF-α (Tumor Necrosis Factor-alpha), IL-1β (Interleukin-1 beta), and NLRP3-related molecules, while HDL-C (High-Density Lipoprotein Cholesterol) levels significantly decreased. Intervention with Bifidobacterium significantly reversed these adverse changes. Further addition of G-3P led to more pronounced improvement in NAFLD symptoms, while overexpression of NLRP3 weakened the protective effects of Bifidobacterium. In vitro results indicated that Ole group exhibited heightened lipid droplet accumulation and expression of NLRP3 inflammasome-related molecules relative to the control group. Treatment with lactic acid effectively reversed these changes; however, the protective effect of lactic acid was significantly weakened with NLRP3 overexpression.

Conclusion

Lactic acid can alleviate lipid metabolism disorders in NAFLD induced by diet through the inhibition of inflammation mediated by the NLRP3 inflammasome and the regulation of the autophagy process.

Type 2 diabetes and the minor allele of PNPLA3 consistently identify high-risk metabolic dysfunction associated steatotic liver disease

BACKGROUND

Association of genetic factors with non-invasive tests (NITs) for MASLD has not been well established.

METHODS

Clinical and laboratory data, liver biopsy and/or liver stiffness measurement (LSM) by transient elastography were collected from MASLD patients seen in tertiary care hepatology practices. Minor allele frequency for genomic loci rs641738 (MBOAT7), rs58542926 (TM6SF2), rs738409 (PNPLA3), rs62305723 (HSD1713B) were evaluated for association with high ELF (≥11.3), high FIB-4 (≥3.25), high LSM (≥10 kPa), histologic fibrosis (stage 3/4 vs. stages 0-2).

RESULTS

Among 2289 MASLD patients with available polymorphism and liver fibrosis/NIT data [52 ± 13 years, 46 % male, BMI 36.6 ± 9.9, 35 % type 2 diabetes (T2D)], 53 % had high-risk allele (C > G) at rs738409 (PNPLA3), 70 % high-risk allele (C > T) at rs641738 (MBOAT7), 18 % high-risk minor allele (C > T) at rs58542926 (TM6SF2), 11 % low-risk minor allele (G > A) at rs62305723 (HSD17b13). Only PNPLA3-rs738409 (47 % CC, 40 % CG, 13 % GG) was significantly associated with higher NIT scores and histologic fibrosis: high ELF 2.8 % CC vs. 8.1 % CG/GG; high FIB-4 4.7 % CC vs. 11.6 % CG/GG; high LSM 10 % vs. 19 %; advanced histologic fibrosis 34 % CC vs. 60 % CG/GG (all p < 0.01). Similar associations of PNPLA3-rs738409 with NITs were observed in a subgroup of MASLD patients with T2D (n = 799; all p < 0.05). The PNPLA3-rs738409 CG/GG genotype, older age and T2D were independently associated with high ELF [OR (95 % CI) = 3.25 (2.03-5.20)], FIB-4 [OR = 2.75 (1.90-3.98)], LSM [OR = 2.71 (1.60-4.59)] scores and advanced histologic fibrosis [OR = 2.56 (1.81-3.62)].

CONCLUSIONS

The polymorphism rs738409 in the PNPLA3 gene, T2D, and older age were independent predictors of high-risk MASLD.

Unraveling Mechanisms of Genetic Risks in Metabolic Dysfunction-Associated Steatotic Liver Diseases: A Pathway to Precision Medicine

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing global health problem, affecting ∼1 billion people. This condition is well established to have a heritable component with strong familial clustering. With the extraordinary breakthroughs in genetic research techniques coupled with their application to large-scale biobanks, the field of genetics in MASLD has expanded rapidly. In this review, we summarize evidence regarding genetic predisposition to MASLD drawn from family and twin studies. Significantly, we delve into detailed genetic variations associated with diverse pathogenic mechanisms driving MASLD. We highlight the interplay between these genetic variants and their connections with metabolic factors, the gut microbiome, and metabolites, which collectively influence MASLD progression. These discoveries are paving the way for precise medicine, including noninvasive diagnostics and therapies. The promising landscape of novel genetically informed drug targets such as RNA interference is explored. Many of these therapies are currently under clinical validation, raising hopes for more effective MASLD treatment.

Recent advances in MASLD genetics: Insights into disease mechanisms and the next frontiers in clinical application

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease in the world and a growing cause of liver-related morbidity and mortality. Yet, at the same time, our understanding of the pathophysiology and genetic underpinnings of this increasingly common yet heterogeneous disease has increased dramatically over the last 2 decades, with the potential to lead to meaningful clinical interventions for patients. We have now seen the first pharmacologic therapy approved for the treatment of MASLD, and multiple other potential treatments are currently under investigation-including gene-targeted RNA therapies that directly extend from advances in MASLD genetics. Here we review recent advances in MASLD genetics, some of the key pathophysiologic insights that human genetics has provided, and the ways in which human genetics may inform our clinical practice in the field of MASLD in the near future.

Global Trend of MASH-associated Liver Cancer: A Systematic Analysis From the Global Burden of Disease 2021

BACKGROUND & AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are the leading causes of liver disease and are emerging as the main risk factors for primary liver cancer (PLC). However, updated global data on MASH remain scarce.

METHODS

This study analyzed data from the Global Burden of Disease study between 2000 and 2021 to assess the age-standardized incidence, mortality, and disability-adjusted life years (DALYs) from MASH-associated PLC, stratified by geographical region, sociodemographic index, age, and sex.

RESULTS

There were 42,290 incident cases, 40,920 deaths, and 995,470 DALYs from PLC globally. Global incidence (+98%), death (+93%), and DALYs (+76%) from MASH-associated PLC increased steeply over the study period. Among different etiologies, only MASH-associated PLC had increased mortality rates (annual percent change [APC], +0.46; 95% confidence interval [CI], 0.33%-0.59%). Africa and low sociodemographic index countries exhibited the highest age-standardized incidence, death, and DALYs from MASH-associated PLC. DALYs increased in females (APC, 0.24%; 95% CI, 0.06%-0.42%), whereas they remained stable in males. Americas experienced the highest percentage increase in age-standardized incidence rate (APC, 2.09%; 95% CI, 2.02%-2.16%), age-standardized death rate (APC, 1.96%; 95% CI, 1.69%-2.23%), and age-standardized DALYs (APC, 1.96%; 95% CI, 1.63%-2.30%) from MASH-associated PLC.

CONCLUSIONS

Over the past 2 decades, the burden of MASH-associated PLC has risen, though there are sociodemographic and geographic disparities. This necessitates urgent strategies across the globe to mitigate the epidemic of MASH-associated PLC as well as its metabolic drivers.

PNPLA3 as a driver of steatotic liver disease: navigating from pathobiology to the clinics via epidemiology

Steatotic liver disease (SLD), particularly metabolic dysfunction-associated SLD, represents a significant public health concern worldwide. Among the various factors implicated in the development and progression of this condition, the patatin-like phospholipase domain-containing protein 3 (PNPLA3 ) gene has emerged as a critical player. Variants of PNPLA3 are associated with altered lipid metabolism, leading to increased hepatic fat accumulation and subsequent inflammation and fibrosis. Understanding the role of PNPLA3 not only enhances our comprehension of the pathomechanisms driving SLD but also informs potential therapeutic strategies. The molecular mechanisms through which PNPLA3 variants contribute to lipid dysregulation and hepatocyte injury in SLD are critically discussed in the present review article. We extensively analyze clinical cohorts and population-based studies underpinning the association between PNPLA3 polymorphisms and the risk of developing SLD, and its liver-related and protean extrahepatic outcomes, in concert with other risk modifiers, notably including age, sex, and ethnicity in adults and children. We also discuss the increasingly recognized role played by the PNPLA3 gene in liver transplantation, autoimmune hepatitis, and acquired immunodeficiency syndrome. Finally, we examine the clinical implications of PNPLA3 diagnostics regarding risk stratification and targeted therapies for patients affected by SLD in the context of precision medicine approaches.

Genetics of Metabolic Dysfunction-associated Steatotic Liver Disease: The State of the Art Update

Recent advances in the genetics of metabolic dysfunction-associated steatotic liver disease (MASLD) are gradually revealing the mechanisms underlying the heterogeneity of the disease and have shown promising results in patient stratification. Genetic characterization of the disease has been rapidly developed using genome-wide association studies, exome-wide association studies, phenome-wide association studies, and whole exome sequencing. These advances have been powered by the increase in computational power, the development of new analytical algorithms, including some based on artificial intelligence, and the recruitment of large and well-phenotyped cohorts. This review presents an update on genetic studies that emphasize new biological insights from next-generation sequencing approaches. Additionally, we discuss innovative methods for discovering new genetic loci for MASLD, including rare variants. To comprehensively manage MASLD, it is important to stratify risks. Therefore, we present an update on phenome-wide association study associations, including extreme phenotypes. Additionally, we discuss whether polygenic risk scores and targeted sequencing are ready for clinical use. With particular focus on precision medicine, we introduce concepts such as the interplay between genetics and the environment in modulating genetic risk with lifestyle or standard therapies. A special chapter is dedicated to gene-based therapeutics. The limitations of approved pharmacological approaches are discussed, and the potential of gene-related mechanisms in therapeutic development is reviewed, including the decision to perform genetic testing in patients with MASLD.

Serial Liver Stiffness Measurement and Fibrosis-4 Scores in Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND

In patients with metabolic dysfunction-associated steatotic liver disease (MASLD), there are limited data on how changes in FIB4 and liver stiffness measurement (LSM) correlate in non-biopsy cohorts.

AIMS

Our objective was to evaluate associations between changes in FIB4 and LSM in MASLD patients.

METHODS

We included MASLD patients with serial VCTE from 2015-2022. The primary predictors were change in FIB4 and presence of diabetes, obesity, and high alanine aminotransferase (ALT). The primary outcome, applied only to patients with LSM1 < 8 kPa, was incident significant fibrosis (SF) defined as a ≥ 20% increase in LSM2 vs. LSM1 and LSM2 ≥ 8 kPa. A secondary outcome was LSM progression with a similar definition but applied to all participants, not only those with LSM1 < 8 kPa.

RESULTS

Of 285 included patients, 216 had LSM1 < 8 kPa and were included in the primary analysis; of these, 34 (16%) had incident SF. Changes in FIB4 correlated with changes in LSM (R = 0.16, p = 0.016). Independent predictors of incident SF included comorbid diabetes mellitus (OR 2.43, 95% CI 1.04-6.56), obesity (OR 3.88, 95% CI 1.63-9.25), and baseline ALT ≥ 30 (OR 8.55, 95% CI 1.10-66.29). A model including ALT, diabetes, and obesity outperformed a model with FIB4 change alone.

CONCLUSION

Among patients with MASLD, changes in FIB4 correlated with changes in LSM but more significant correlates of incident significant fibrosis included diabetes mellitus, obesity, and high baseline ALT.

TM6SF2 -rs58542926 Genotype Has Opposing Effects on Incidence of Hepatic and Cardiac Events in a Community Cohort

INTRODUCTION

TM6SF2 -rs58542926-T is associated with increased cirrhosis and modestly decreased coronary artery disease prevalence. However, relative effects of TM6SF2 genotype on major adverse cardiovascular events (MACE) vs liver-related events (LRE) are not known.

METHODS

We used the UK Biobank, a prospective cohort with genetic and inpatient diagnosis data. The primary predictor was TM6SF2 -rs58542926 genotype, and the primary outcomes were MACE and LRE. Effects were reported as subhazard ratios (sHRs) and 10-year cumulative incidence by Fine-Gray competing risk analyses.

RESULTS

More than 430,000 individuals met inclusion criteria. TM6SF2 -rs58542926-TT genotype (vs CC) was associated with higher incidence of LRE (adjusted sHR 3.16, 95% confidence interval 1.86-5.37) and lower incidence of MACE (adjusted sHR for TT vs CC genotype 0.76, 95% confidence interval 0.63-0.91). In individuals with fibrosis-4 (FIB4) < 1.3, 1.3-2.67, and > 2.67, 10-year LRE incidence in TM6SF2 -rs58542926-TT vs CC individuals was 0.08% vs 0.06% ( P > 0.05), 0.81% vs 0.20% ( P < 0.0001), and 10.5% vs 3.4% ( P = 0.00094), respectively. The corresponding values for MACE were 3.8% vs 5.1% ( P = 0.032), 6.4% vs 8.2% ( P = 0.040), and 17.1% vs 12.4% ( P > 0.05). The absolute decrease in MACE with rs58542926-TT (vs CC) genotype exceeded the absolute increase in LRE in all groups but FIB4 > 2.67. Associations of TM6SF2 genotype with LRE/MACE were significant in men but not women. TM6SF2 -rs58542926-T allele was also associated with increased hepatic steatosis and corrected T1 time by magnetic resonance imaging, with greater effect sizes in men than women.

DISCUSSION

TM6SF2 genotype has opposite effects on LRE vs MACE incidence, and absolute effects on MACE were greater except in those with highest FIB4 scores. Effects were strongest in men. These findings clarify implications of TM6SF2 genotype based on personalized clinical risk.

Drivers of cardiovascular disease in metabolic dysfunction-associated steatotic liver disease: the threats of oxidative stress

Non-alcoholic fatty liver disease (NAFLD), now known as metabolic-associated steatotic liver disease (MASLD), is the most common liver disease worldwide, with a prevalence of 38%. In these patients, cardiovascular disease (CVD) is the number one cause of mortality rather than liver disease. Liver abnormalities per se due to MASLD contribute to risk factors such as dyslipidemia and obesity and increase CVD incidents. In this review we discuss hepatic pathophysiological changes the liver of MASLD leading to cardiovascular risks, including liver sinusoidal endothelial cells, insulin resistance, and oxidative stress with a focus on glutathione metabolism and function. In an era where there is an increasingly robust recognition of what causes CVD, such as the factors included by the American Heart Association in the recently developed PREVENT equation, the inclusion of liver disease may open doors to how we approach treatment for MASLD patients who are at risk of CVD.

EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously termed non-alcoholic fatty liver disease (NAFLD), is defined as steatotic liver disease (SLD) in the presence of one or more cardiometabolic risk factor(s) and the absence of harmful alcohol intake. The spectrum of MASLD includes steatosis, metabolic dysfunction-associated steatohepatitis (MASH, previously NASH), fibrosis, cirrhosis and MASH-related hepatocellular carcinoma (HCC). This joint EASL-EASD-EASO guideline provides an update on definitions, prevention, screening, diagnosis and treatment for MASLD. Case-finding strategies for MASLD with liver fibrosis, using non-invasive tests, should be applied in individuals with cardiometabolic risk factors, abnormal liver enzymes, and/or radiological signs of hepatic steatosis, particularly in the presence of type 2 diabetes (T2D) or obesity with additional metabolic risk factor(s). A stepwise approach using blood-based scores (such as FIB-4) and, sequentially, imaging techniques (such as transient elastography) is suitable to rule-out/in advanced fibrosis, which is predictive of liver-related outcomes. In adults with MASLD, lifestyle modification - including weight loss, dietary changes, physical exercise and discouraging alcohol consumption - as well as optimal management of comorbidities - including use of incretin-based therapies (e.g. semaglutide, tirzepatide) for T2D or obesity, if indicated - is advised. Bariatric surgery is also an option in individuals with MASLD and obesity. If locally approved and dependent on the label, adults with non-cirrhotic MASH and significant liver fibrosis (stage ≥2) should be considered for a MASH-targeted treatment with resmetirom, which demonstrated histological effectiveness on steatohepatitis and fibrosis with an acceptable safety and tolerability profile. No MASH-targeted pharmacotherapy can currently be recommended for the cirrhotic stage. Management of MASH-related cirrhosis includes adaptations of metabolic drugs, nutritional counselling, surveillance for portal hypertension and HCC, as well as liver transplantation in decompensated cirrhosis.

Metabolic dysfunction-associated liver disease and diabetes: Matrix remodeling, fibrosis, and therapeutic implications

Metabolic dysfunction-associated liver disease (MASLD) and steatohepatitis (MASH) are becoming the most common causes of chronic liver disease in the United States and worldwide due to the obesity and diabetes epidemics. It is estimated that by 2030 close to 100 million people might be affected and patients with type 2 diabetes are especially at high risk. Twenty to 30% of patients with MASLD can progress to MASH, which is characterized by steatosis, necroinflammation, hepatocyte ballooning, and in advanced cases, fibrosis progressing to cirrhosis. Clinically, it is recognized that disease progression in diabetic patients is accelerated and the role of various genetic and epigenetic factors, as well as cell-matrix interactions in fibrosis and stromal remodeling, have recently been recognized. While there has been great progress in drug development and clinical trials for MASLD/MASH, the complexity of these pathways highlights the need to improve diagnosis/early detection and develop more successful antifibrotic therapies that not only prevent but reverse fibrosis.

Editorial: Genetics for non-invasive risk stratification-Finding the needle in the haystack?

This article is linked to Bridi et al papers. To view these articles, visit https://doi.org/10.1111/apt.18099 and https://doi.org/10.1111/apt.18129

The impact of genetic risk on the prevalence of advanced fibrosis and cirrhosis in prospectively assessed patients with type 2 diabetes

BACKGROUND

Genetic factors contribute to the risk and severity of metabolic dysfunction-associated steatotic liver disease (MASLD). However, the utility of genetic testing in risk stratification remains poorly characterised.

AIMS

To examine the influence of genetic risk on advanced fibrosis and cirrhosis in patients with type 2 diabetes mellitus (T2DM) and the utility of a polygenic risk score (PRS) in screening guidelines.

METHODS

We prospectively enrolled adults aged ≥50 years with T2DM recruited from clinics. PRS was the sum of risk alleles in PNPLA3, TM6SF2 and SERPINA1 minus the protective variant in HSD17B13. We performed magnetic resonance elastography and vibration-controlled transient elastography to assess for advanced fibrosis and cirrhosis.

RESULTS

Of 382 included patients, the mean age and BMI were 64.8 (±8.4) years and 31.7 (±6.2) kg/m2 respectively. The prevalence of advanced fibrosis and cirrhosis were 12.3% and 5.2% respectively; higher PRS was associated with increased risk of cirrhosis (2.7% vs. 7.5%, p = 0.037). High PRS was associated with increased risk of advanced fibrosis among those with fibrosis-4 index (FIB-4) index <1.3 (9.6% vs. 2.3%, p = 0.036) but was not significantly different in other FIB-4 categories. Incorporating PRS determination into the American Gastroenterological Association and American Association for the Study of Liver Diseases screening guidelines prevented approximately 20% of all participants with advanced fibrosis from being inappropriately classified as low risk.

CONCLUSIONS

Utilising a well-phenotyped, prospective cohort of adults with T2DM, we found that adding an assessment of genetic risk to recommendations to screen at-risk populations may improve risk prediction.

Severe hepatic steatosis promotes increased liver stiffness in the early stages of metabolic dysfunction-associated steatotic liver disease

BACKGROUND & AIMS

The predictors of progression from steatosis to more advanced stages of metabolic dysfunction-associated steatotic liver disease (MASLD) remain unclear. We evaluated the association between the quantity of hepatic steatosis and longitudinal changes in liver stiffness measurements (LSMs) using magnetic resonance elastography (MRE) in patients with MASLD.

METHODS

We retrospectively analysed patients with MASLD who underwent at least two serial MRE and magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) examinations at least 1 year apart. Fine-Gray competitive proportional hazard regression was used to identify LSM progression and regression factors.

RESULTS

A total of 471 patients were enrolled. Factors linked to LSM progression were steatosis grade 3 (MRI-PDFF ≥17.1%, adjusted hazard ratio [aHR] 2.597; 95% confidence interval [CI] 1.483-4.547) and albumin-bilirubin grade 2 or 3 (aHR 2.790; 95% CI 1.284-6.091), while the only factor linked to LSM regression was % decrease rate of MRI-PDFF ≥5% (aHR 2.781; 95% CI 1.584-4.883). Steatosis grade 3 correlated with a higher incidence rate of LSM progression than steatosis grade 1 (MRI-PDFF <11.3%) in patients with LSM stage 0 (<2.5 kilopascal [kPa]), and a % annual decrease rate of MRI-PDFF ≥5% correlated with a higher incidence rate of LSM regression than that of MRI-PDFF >-5% and <5% in patients with LSM stage 1 or 2-4 (≥2.5 kPa).

CONCLUSIONS

Severe hepatic steatosis was linked to significant LSM progression in patients with MASLD and low LSM (<2.5 kPa).

Insulin resistance is an integral feature of MASLD even in the presence of PNPLA3 variants

Background & Aims

It has been postulated that carriers of PNPLA3 I148M (CG [Ile/Met] or GG [Met/Met]) develop metabolic dysfunction-associated steatotic liver disease (MASLD) in the absence of insulin resistance or metabolic syndrome. However, the relationship between insulin resistance and MASLD according to the PNPLA3 allele has not been carefully assessed.

Methods

A total of 204 participants were recruited and underwent PNPLA3 genotyping, an oral glucose tolerance test, liver proton magnetic resonance spectroscopy and percutaneous liver biopsy if diagnosed with MASLD. A subgroup of patients (n = 55) had an euglycemic hyperinsulinemic clamp with glucose tracer infusion.

Results

As expected, patients with the CG/GG genotype had worse intrahepatic triglyceride content and worse liver histology. However, regardless of PNPLA3 genotype, patients with a diagnosis of MASLD had severe whole-body insulin resistance (Matsuda index, an estimation of insulin resistance in glucose metabolic pathways) and fasting and postprandial adipose tissue insulin resistance (Adipo-IR index and free fatty acid suppression during the oral glucose tolerance test, respectively, as measures of insulin resistance in lipolytic metabolic pathways) compared to patients without MASLD. Moreover, for the same amount of liver fat accumulation, insulin resistance was similar in patients with genotypes CC vs. CG/GG. In multiple regression analyses, A1c and Adipo-IR were associated with the presence of MASLD and advanced liver fibrosis, independently of PNPLA3 genotype.

Conclusions

PNPLA3 variant carriers with MASLD are equally insulin resistant as non-carriers with MASLD at the level of the liver, muscle, and adipose tissue. This calls for reframing "PNPLA3 MASLD" as an insulin-resistant condition associated with increased hepatic susceptibility to metabolic insults, such as obesity or diabetes, wherein early identification and aggressive intervention are warranted to reverse metabolic dysfunction and prevent disease progression.

Impact and implications

It has been proposed that the PNPLA3 G allele is associated with the presence of metabolic dysfunction-associated steatotic liver disease (MASLD) in the absence of insulin resistance. However, our results suggest that regardless of PNPLA3 alleles, the presence of insulin resistance is necessary for the development of MASLD. This calls for reframing patients with "PNPLA3 MASLD" not as insulin sensitive, but on the contrary, as an insulin-resistant population with increased hepatic susceptibility to metabolic insults, such as obesity or diabetes.

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.

EASL-EASD-EASO Clinical Practice Guidelines on the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously termed non-alcoholic fatty liver disease (NAFLD), is defined as steatotic liver disease (SLD) in the presence of one or more cardiometabolic risk factor(s) and the absence of harmful alcohol intake. The spectrum of MASLD includes steatosis, metabolic dysfunction-associated steatohepatitis (MASH, previously NASH), fibrosis, cirrhosis and MASH-related hepatocellular carcinoma (HCC). This joint EASL-EASD-EASO guideline provides an update on definitions, prevention, screening, diagnosis and treatment for MASLD. Case-finding strategies for MASLD with liver fibrosis, using non-invasive tests, should be applied in individuals with cardiometabolic risk factors, abnormal liver enzymes, and/or radiological signs of hepatic steatosis, particularly in the presence of type 2 diabetes (T2D) or obesity with additional metabolic risk factor(s). A stepwise approach using blood-based scores (such as FIB-4) and, sequentially, imaging techniques (such as transient elastography) is suitable to rule-out/in advanced fibrosis, which is predictive of liver-related outcomes. In adults with MASLD, lifestyle modification - including weight loss, dietary changes, physical exercise and discouraging alcohol consumption - as well as optimal management of comorbidities - including use of incretin-based therapies (e.g. semaglutide, tirzepatide) for T2D or obesity, if indicated - is advised. Bariatric surgery is also an option in individuals with MASLD and obesity. If locally approved and dependent on the label, adults with non-cirrhotic MASH and significant liver fibrosis (stage ≥2) should be considered for a MASH-targeted treatment with resmetirom, which demonstrated histological effectiveness on steatohepatitis and fibrosis with an acceptable safety and tolerability profile. No MASH-targeted pharmacotherapy can currently be recommended for the cirrhotic stage. Management of MASH-related cirrhosis includes adaptations of metabolic drugs, nutritional counselling, surveillance for portal hypertension and HCC, as well as liver transplantation in decompensated cirrhosis.

Surveillance of the liver in type 2 diabetes: important but unfeasible?

Fatty liver plays a pivotal role in the pathogenesis of the metabolic syndrome and type 2 diabetes. According to an updated classification, any individual with liver steatosis and one or more features of the metabolic syndrome, without excess alcohol consumption or other known causes of steatosis, has metabolic dysfunction-associated steatotic liver disease (MASLD). Up to 60-70% of all individuals with type 2 diabetes have MASLD. However, the prevalence of advanced liver fibrosis in type 2 diabetes remains uncertain, with reported estimates of 10-20% relying on imaging tests and likely overestimating the true prevalence. All stages of MASLD impact prognosis but fibrosis is the best predictor of all-cause and liver-related mortality risk. People with type 2 diabetes face a two- to threefold increase in the risk of liver-related death and hepatocellular carcinoma, with 1.3% progressing to severe liver disease over 7.7 years. Because reliable methods for detecting steatosis are lacking, MASLD mostly remains an incidental finding on imaging. Regardless, several medical societies advocate for universal screening of individuals with type 2 diabetes for advanced fibrosis. Proposed screening pathways involve annual calculation of the Fibrosis-4 (FIB-4) index, followed by a secondary test such as transient elastography (TE) for intermediate-to-high-risk individuals. However, owing to unsatisfactory biomarker specificity, these pathways are expected to channel approximately 40% of all individuals with type 2 diabetes to TE and 20% to tertiary care, with a false discovery rate of up to 80%, raising concerns about feasibility. There is thus an urgent need to develop more effective strategies for surveying the liver in type 2 diabetes. Nonetheless, weight loss through lifestyle changes, pharmacotherapy or bariatric surgery remains the cornerstone of management, proving highly effective not only for metabolic comorbidities but also for MASLD. Emerging evidence suggests that fibrosis biomarkers may serve as tools for risk-based targeting of weight-loss interventions and potentially for monitoring response to therapy.

PNPLA3 risk allele is associated with risk of hepatocellular carcinoma but not decompensation in compensated cirrhosis

BACKGROUND

The PNPLA3-rs738409-G, TM6SF2-rs58542926-T, and HSD17B13-rs6834314-A polymorphisms have been associated with cirrhosis, hepatic decompensation, and HCC. However, whether they remain associated with HCC and decompensation in people who already have cirrhosis remains unclear, which limits the clinical utility of genetics in risk stratification as HCC is uncommon in the absence of cirrhosis. We aimed to characterize the effects of PNPLA3, TM6SF2, and HSD17B13 genotype on hepatic decompensation, HCC, and liver-related mortality or liver transplant in patients with baseline compensated cirrhosis.

METHODS

We conducted a single-center retrospective study of patients in the Michigan Genomics Initiative who underwent genotyping. The primary predictors were PNPLA3, TM6SF2, and HSD17B13 genotypes. Primary outcomes were either hepatic decompensation, HCC, or liver-related mortality/transplant. We conducted competing risk Fine-Gray analyses on our cohort.

RESULTS

We identified 732 patients with baseline compensated cirrhosis. During follow-up, 50% of patients developed decompensation, 13% developed HCC, 24% underwent liver transplant, and 27% died. PNPLA3-rs738409-G genotype was associated with risk of incident HCC: adjusted subhazard hazard ratio 2.42 (1.40-4.17), p=0.0015 for PNPLA3-rs738409-GG vs. PNPLA3-rs738409-CC genotype. The 5-year cumulative incidence of HCC was higher in PNPLA3-rs738409-GG carriers than PNPLA3-rs738409-CC/-CG carriers: 15.6% (9.0%-24.0%) vs. 7.4% (5.2%-10.0%), p<0.001. PNPLA3 genotype was not associated with decompensation or the combined outcome of liver-related mortality or liver transplant. TM6SF2 and HSD17B13 genotypes were not associated with decompensation or HCC.

CONCLUSIONS

The PNPLA3-rs738409-G allele is associated with an increased risk of HCC among patients with baseline compensated cirrhosis. People with cirrhosis and PNPLA3-rs738409-GG genotype may warrant more intensive HCC surveillance.

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.

Age, BMI, and Type 2 Diabetes Modify the Relationship Between PNPLA3 and Advanced Fibrosis in Children and Adults With NAFLD

BACKGROUND & AIMS

PNPLA3 G-allele is an important determinant of disease severity in nonalcoholic fatty liver disease (NAFLD). Here, we investigated the effect of age, body mass index (BMI), and type 2 diabetes mellitus (T2DM) on the relationship between PNPLA3 G-allele and advanced fibrosis in adults and children with histologically characterized NAFLD.

METHODS

A total of 1047 children and 2057 adults were included. DNA was genotyped for rs738409 in duplicate. Primary outcome of interest was advanced fibrosis (fibrosis stage ≥3). Regression analyses were performed after controlling for relevant covariates. An additive model was used to assess the effect of PNPLA3 G-allele (CC vs CG vs GG).

RESULTS

PNPLA3 G-allele was significantly associated with advanced fibrosis in children (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.16-2.09) and adults (OR, 1.55; 95% CI, 1.16-1.54). Across the cohort, older age significantly increased the risk for advanced fibrosis for PNPLA3 CC (OR, 1.019; 95% CI, 1.013-1.026), CG (OR, 1.024; 95% CI, 1.018-1.030), and GG (OR, 1.03; 95% CI, 1.023-1.037) genotypes. BMI significantly increased the relationship between PNPLA3 genotypes and advanced fibrosis in children and adults. A BMI of 30 kg/m2 was the cutoff beyond which PNPLA3 G-allele had exponential effect on the risk for advanced fibrosis in children and adults. T2DM significantly worsened the relationship between PNPLA3 G-allele and advanced fibrosis in children and adults (interaction P < .01 for both).

CONCLUSIONS

Age, BMI, and T2DM modify the risk of advanced fibrosis associated with PNPLA3 G-allele. Preventing or reversing T2DM and obesity in persons carrying PNPLA3 G-allele may lower the risk for advanced fibrosis in NAFLD.

Genetics of liver disease in adults

Chronic liver disease stands as a significant global health problem with an estimated 2 million annual deaths across the globe. Combining the use of next-generation sequencing technologies with evolving knowledge in the interpretation of genetic variation across the human genome is propelling our understanding, diagnosis, and management of both rare and common liver diseases. Here, we review the contribution of risk and protective alleles to common forms of liver disease, the rising number of monogenic diseases affecting the liver, and the role of somatic genetic variants in the onset and progression of oncological and non-oncological liver diseases. The incorporation of genomic information in the diagnosis and management of patients with liver disease is driving the beginning of a new era of genomics-informed clinical hepatology practice, facilitating personalized medicine, and improving patient care.

Hepatic Fibrosis and Cancer: The Silent Threats of Metabolic Syndrome

Metabolic dysfunction-associated steatotic (fatty) liver disease (MASLD), previously termed non-alcoholic fatty liver disease, is a worldwide epidemic that can lead to hepatic inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The disease is typically a component of the metabolic syndrome that accompanies obesity, and is often overlooked because the liver manifestations are clinically silent until late-stage disease is present (i.e., cirrhosis). Moreover, Asian populations, including Koreans, have a higher fraction of patients who are lean, yet their illness has the same prognosis or worse than those who are obese. Nonetheless, ongoing injury can lead to hepatic inflammation and ballooning of hepatocytes as classic features. Over time, fibrosis develops following activation of hepatic stellate cells, the liver's main fibrogenic cell type. The disease is usually more advanced in patients with type 2 diabetes mellitus, indicating that all diabetic patients should be screened for liver disease. Although there has been substantial progress in clarifying pathways of injury and fibrosis, there no approved therapies yet, but current research seeks to uncover the pathways driving hepatic inflammation and fibrosis, in hopes of identifying new therapeutic targets. Emerging molecular methods, especially single cell sequencing technologies, are revolutionizing our ability to clarify mechanisms underlying MASLD-associated fibrosis and HCC.

NAFLD Fibrosis Progression and Type 2 Diabetes: The Hepatic-Metabolic Interplay

The bidirectional relationship between type 2 diabetes and (non-alcoholic fatty liver disease) NAFLD is indicated by the higher prevalence and worse disease course of one condition in the presence of the other, but also by apparent beneficial effects observed in one, when the other is improved. This is partly explained by their belonging to a multisystemic disease that includes components of the metabolic syndrome and shared pathogenetic mechanisms. Throughout the progression of NAFLD to more advanced stages, complex systemic and local metabolic derangements are involved. During fibrogenesis, a significant metabolic reprogramming occurs in the hepatic stellate cells, hepatocytes, and immune cells, engaging carbohydrate and lipid pathways to support the high-energy-requiring processes. The natural history of NAFLD evolves in a variable and dynamic manner, probably due to the interaction of a variable number of modifiable (diet, physical exercise, microbiota composition, etc.) and non-modifiable (genetics, age, ethnicity, etc.) risk factors that may intervene concomitantly, or subsequently/intermittently in time. This may influence the risk (and rate) of fibrosis progression/regression. The recognition and control of the factors that determine a rapid progression of fibrosis (or its regression) are critical, as the fibrosis stages are associated with the risk of liver-related and all-cause mortality.

Exercise training improves serum biomarkers of liver fibroinflammation in patients with metabolic dysfunction-associated steatohepatitis

BACKGROUND AND AIMS

Exercise training is recommended for all patients with metabolic dysfunction-associated steatotic liver disease and may reverse liver fibrosis. Whether exercise training improves liver fibrosis without body weight loss remains controversial. We further investigated this relationship using serum biomarkers of liver fibroinflammation in a post hoc analysis of an exercise trial where patients did not lose significant body weight.

METHODS

In the NASHFit trial, patients with metabolic dysfunction-associated steatohepatitis were randomized to receive either moderate-intensity aerobic exercise training or standard clinical care for 20 weeks. Mediterranean-informed dietary counselling was provided to each group. Change in serum biomarkers was measured and compared between the two groups.

RESULTS

Exercise training led to improvement in serum biomarkers of liver fibroinflammation, including (1) ≥17 IU/L reduction in alanine aminotransferase (ALT) in 53% of individuals in the exercise training group compared to 13% in the standard clinical care group (p < 0.001; mean reduction 24% vs. 10% respectively) and (2) improvement in CK18 (-61 vs. +71 ng/mL, p = 0.040). ALT improvement ≥17 IU/L was correlated with ≥30% relative reduction in magnetic resonance imaging-measured liver fat and PNPLA3 genotype.

CONCLUSION

Exercise training improves multiple serum biomarkers of liver fibroinflammation at clinically significant thresholds of response without body weight loss. This study provides further evidence that exercise training should be viewed as a weight-neutral intervention for which response to intervention can be readily monitored with widely available non-invasive biomarkers that can be applied at the population level.

Associations between metabolic hyperferritinaemia, fibrosis-promoting alleles and clinical outcomes in steatotic liver disease

BACKGROUND & AIMS

Ferritin has been investigated as a biomarker for liver fibrosis and iron in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). However, whether metabolic hyperferritinaemia predicts progression of liver disease remains unknown. In this study, we sought to understand associations between hyperferritinaemia and (1) adverse clinical outcomes and (2) common genetic variants related to iron metabolism and liver fibrosis.

METHODS

This was a retrospective analysis of adults with MASLD seen at the University of Michigan Health System, where MASLD was defined by hepatic steatosis on imaging, biopsy or vibration-controlled transient elastography, plus metabolic risk factors in the absence of chronic liver diseases other than hemochromatosis. The primary predictor was serum ferritin level, which was dichotomized based on a cut-off of 300 or 450 mcg/L for women or men. Primary outcomes included (1) incident cirrhosis, liver-related events, congestive heart failure (CHF), and mortality and (2) distribution of common genetic variants associated with hepatic fibrosis and hereditary hemochromatosis.

RESULTS

Of 7333 patients with MASLD, 1468 (20%) had elevated ferritin. In multivariate analysis, ferritinaemia was associated with increased mortality (HR 1.68 [1.35-2.09], p < .001) and incident liver-related events (HR 1.92 [1.11-3.32], p = .019). Furthermore, elevated ferritin was associated with carriage of cirrhosis-promoting alleles including PNPLA3-rs738409-G allele (p = .0068) and TM6SF2-rs58542926-T allele (p = 0.0083) but not with common HFE mutations.

CONCLUSIONS

In MASLD patients, metabolic hyperferritinaemia was associated with increased mortality and higher incidence of liver-related events, and cirrhosis-promoting alleles but not with iron overload-promoting HFE mutations.

Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis With Liver Fibrosis as Predictors of New-Onset Diabetes Mellitus in People With HIV: A Longitudinal Cohort Study

BACKGROUND

We investigated the association between nonalcoholic fatty liver disease (NAFLD) plus or minus a concurrent diagnosis of nonalcoholic steatohepatitis (NASH) and incident diabetes mellitus (DM) and the risk factors associated with NAFLD or NASH development.

METHODS

In this prospective study, we analyzed people with human immunodeficiency virus (HIV; PWH) aged ≥18 years without excessive alcohol consumption or hepatitis coinfections. NAFLD was defined as controlled attenuation parameter ≥248 dB/m, whereas NASH with significant disease activity and liver fibrosis was defined as a FibroScan-AST score ≥0.67. Cox proportional hazard regression was used to investigate the association between NAFLD with or without NASH and new-onset DM.

RESULTS

Of 847 PWH, the median age at baseline was 45 years (interquartile range, 38-51; 43% female). Baseline NAFLD was associated with 2.8-fold higher risk of new-onset DM after adjusting for age, sex, family history of DM, antiretroviral therapy duration, smoking, statin use, stavudine/didanosine/zidovudine exposure, time-updated body mass index, hypertension, and dyslipidemia. Combined NAFLD and NASH at baseline had 3.1-fold higher new-onset DM risk. In separate analyses, baseline DM did not predict progression to NAFLD or NASH, but tenofovir alafenamide use was associated with an increased risk of NAFLD (hazard ratio [HR], 2.01; 95% confidence interval [CI], 1.02-4.02) or NASH development (2.31; 95% CI, 1.12-5.11).

CONCLUSIONS

NAFLD alone or combined with NASH strongly predicts new-onset DM. This highlights the need for systematic risk assessments and management of NAFLD/NASH, as it may contribute to metabolic complications such as DM and subsequent cardiovascular diseases in PWH.

A common variant that alters SUN1 degradation associates with hepatic steatosis and metabolic traits in multiple cohorts

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD), and its progressive form steatohepatitis (NASH), represent a genetically and phenotypically diverse entity for which there is no approved therapy, making it imperative to define the spectrum of pathways contributing to its pathogenesis. Rare variants in genes encoding nuclear envelope proteins cause lipodystrophy with early-onset NAFLD/NASH; we hypothesized that common variants in nuclear envelope-related genes might also contribute to hepatic steatosis and NAFLD.

METHODS

Using hepatic steatosis as the outcome of interest, we performed an association meta-analysis of nuclear envelope-related coding variants in three large discovery cohorts (N >120,000 participants), followed by phenotype association studies in large validation cohorts (N >600,000) and functional testing of the top steatosis-associated variant in cell culture.

RESULTS

A common protein-coding variant, rs6461378 (SUN1 H118Y), was the top steatosis-associated variant in our association meta-analysis (p <0.001). In ancestrally distinct validation cohorts, rs6461378 associated with histologic NAFLD and with NAFLD-related metabolic traits including increased serum fatty acids, type 2 diabetes, hypertension, cardiovascular disease, and decreased HDL. SUN1 H118Y was subject to increased proteasomal degradation relative to wild-type SUN1 in cells, and SUN1 H118Y-expressing cells exhibited insulin resistance and increased lipid accumulation.

CONCLUSIONS

Collectively, these data support a potential causal role for the common SUN1 variant rs6461378 in NAFLD and metabolic disease.

IMPACT AND IMPLICATIONS

Non-alcoholic fatty liver disease (NAFLD), with an estimated global prevalence of nearly 30%, is a growing cause of morbidity and mortality for which there is no approved pharmacologic therapy. Our data provide a rationale for broadening current concepts of NAFLD genetics and pathophysiology to include the nuclear envelope, and particularly Sad1 and UNC84 domain containing 1 (SUN1), as novel contributors to this common liver disease. Furthermore, if future studies confirm causality of the common SUN1 H118Y variant, it has the potential to become a broadly relevant therapeutic target in NAFLD and metabolic disease.

The Surreptitious Burden of Nonalcoholic Fatty Liver Disease in the Elderly in the Asia-Pacific Region: An Insight from the Global Burden of Disease Study 2019

Nonalcoholic fatty liver disease (NAFLD) represents a significant health threat worldwide. The aging population and a rise in metabolic syndrome in Asia might influence the epidemiology of NAFLD among the elderly. However, there is a lack of understanding of the burden and recommendations for NAFLD in this group. Our study sought to investigate the trends in the NAFLD burden among the elderly in the Asia-Pacific region. We employed data from the Global Burden of Disease 2019 study for an in-depth analysis of the prevalence and disability-adjusted life years (DALYs) along with age-standardized rate (ASR) associated with NAFLD in elderly populations (age 65-89 years) across the Asia-Pacific region, including the Southeast Asia (SEA) and Western Pacific (WP) regions, from 2010 to 2019. This study also examined the trends and disparities in NAFLD burden across different nations and sexes. In 2019, there were over 120 million cases of NAFLD in the elderly in the Asia-Pacific region. The ASR of prevalence was higher in SEA compared to WP (36,995.37 vs. 32,821.78 per 100,000). ASR of prevalence increased with annual percentage change (APC) +0.95% in the WP while it increased by +0.87% in SEA. During the study period, the ASR of DALYs decreased in SEA (APC -0.41%) but remained stable in the WP region. The burden of NAFLD in the elderly population in Asia-Pacific has increased, underscoring the timely intervention to tackle this high and rising burden.

Towards precision medicine in non-alcoholic fatty liver disease

Non-Alcoholic Fatty Liver Disease (NAFLD) refers to the accumulation of lipid laden vacuoles in hepatocytes, occurring in the context of visceral adiposity, insulin resistance and other features of the metabolic syndrome. Its more severe form (NASH, Non-Alcoholic Steatohepatitis) is becoming the leading aetiology of end-stage liver disease and hepatocellular carcinoma, and also contributes to cardiovascular disease, diabetes and extrahepatic malignancy. Management is currently limited to lifestyle modification and optimisation of the metabolic co-morbidities, with some of the drugs used for the latter also having shown some benefit for the liver. Licensed treatment modalities are currently lacking. A particular difficulty is the notorious heterogeneity of the patient population, which is poorly understood. A spectrum of disease severity associates in a non-linear way with a spectrum of severity of underlying metabolic factors. Heterogeneity of the liver in terms of mechanisms to cope with the metabolic and inflammatory stress and in terms of repair mechanisms, and a lack of knowledge hereof, further complicate the understanding of inter-individual variability. Genetic factors act as disease modifiers and potentially allow for some risk stratification, but also only explain a minor fraction of disease heterogeneity. Response to treatment shows a large variation in treatment response, again with little understanding of what is driving the absence of response in individual patients. Management can be tailored to patient's preferences in terms of diet modification, but tailoring treatment to knowledge on disease driving mechanisms in an individual patient is still in its infancy. Recent progress in analysing liver tissue as well as non-invasive tests hold, however, promise to rapidly improve our understanding of disease heterogeneity in NAFLD and provide individualised management.