Abdominal obesity and alcohol use modify the impact of genetic risk for incident advanced liver disease in the general population

Genetic Risk Factors for Steatotic Liver Disease After Liver Transplantation

BACKGROUND

The role of genetic risk factors for steatotic liver disease (SLD) is intriguing in liver transplantation (LT), as both donor and recipient genetic factors may play a role. There are only a few small-scale studies published so far.

METHODS

We analysed the incidence and risk factors for post-LT SLD and the impact of 56 SLD-associated genetic variants in 595 donor-recipient pairs with liver biopsy available ≥ 6 months after LT. We evaluated whether the polygenic risk score (PRS-5) improves the ability to predict post-LT SLD in addition to non-genetic risk factors.

RESULTS

SLD after LT was diagnosed in 34.5% of patients during a median 7.6-year follow-up. In multivariate analysis including non-genetic risk factors, donor PNPLA3 rs738409-G (HR for SLD: C/G 1.34, p = 0.051, G/G 2.25, p = 0.004), donor HSD17B13 rs72613567-TA (HR for SLD: TA/T 0.68, p = 0.02 TA/TA HR 0.50, p = 0.10) and recipient UCP2 rs695366-G (HR for SLD: A/G 0.63, p = 0.002, G/G HR 0.50, p = 0.04) appeared as the most important genetic risk factors for post-LT SLD. The addition of PRS-5 to a multivariate regression model (including non-genetic risk factors) improved the predictive ability for SLD only modestly (AUC 0.78 to 0.80).

CONCLUSIONS

Various genetic variants contribute to post-LT SLD with separate variants among recipients and donors, with donor PNPLA3 rs738409-G as the most significant risk allele. Still, donor and recipient genotyping provide only modest additional value for individual risk stratification over phenotype data, highlighting the role of modifiable risk factors.

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.

Prediction of major liver-related events in the population using prognostic models

Liver disease poses a significant global health burden, with steatotic liver disease related to metabolic dysfunction and/or alcohol use being the most prevalent type. Current risk stratification strategies emphasize detecting advanced fibrosis as a surrogate marker for liver-related events (LREs), such as hospitalization, liver cancer, or death. However, fibrosis alone does not adequately predict imminent outcomes, particularly in fast-progressing individuals without advanced fibrosis at evaluation. This underscores the need for models designed specifically to predict LREs, enabling timely interventions. The Chronic Liver Disease (CLivD) risk score, the dynamic aspartate aminotransferase-to-alanine aminotransferase ratio (dAAR), and the Cirrhosis Outcome Risk Estimator (CORE) were explicitly developed to predict LRE risk rather than detect fibrosis. Derived from general population cohorts, these models incorporate either standard liver enzymes (dAAR and CORE) or risk factors (CLivD), enabling broad application in primary care and population-based settings. They directly estimate the risk of future LREs, improving on traditional fibrosis-focused approaches. Conversely, widely used models like the Fibrosis-4 index and newer ones, such as the LiverRisk and LiverPRO scores, were initially developed to detect significant/advanced fibrosis or liver stiffness. While not designed for LRE prediction, they have later been analyzed for this purpose. Integrating fibrosis screening with LRE-focused models like CLivD, dAAR, and CORE can help healthcare systems adopt proactive, preventive care. This approach emphasizes identifying individuals at imminent risk of severe outcomes, potentially ensuring better resource allocation and personalized interventions.

PNPLA3 I148M Interacts With Environmental Triggers to Cause Human Disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects up to 30% of Western populations. While obesity is a recognized risk factor, MASLD does not develop in all obese individuals, highlighting the need to understand genetic and environmental interactions. The PNPLA3 I148M variant has been identified as a key genetic risk factor, significantly increasing the likelihood of MASLD development and progression.

METHODS

We reviewed current literature on the role of PNPLA3 I148M in MASLD, focusing on gene-environment interactions involving diet, physical activity, obesity, and insulin resistance. We included studies analysing ethnic differences in PNPLA3 I148M prevalence and its association with MASLD. Additionally, we reviewed data on how PNPLA3 I148M influences the response to therapies, including lipid-lowering medications and GLP-1 agonists.

RESULTS

The PNPLA3 I148M variant markedly heightens MASLD risk, particularly in Hispanic populations, where a higher prevalence of MASLD is observed. Lifestyle factors such as high sugar intake, alcohol consumption, and physical inactivity exacerbate MASLD risk among I148M carriers. Evidence shows that insulin resistance amplifies MASLD risk associated with the I148M variant, especially in non-diabetic individuals. Moreover, the PNPLA3 I148M variant interacts with other genetic loci, further modifying MASLD risk and disease course. The variant also influences treatment response, with variability observed in effectiveness of lipid-lowering therapies and GLP-1 agonists among carriers.

CONCLUSION

The interplay between PNPLA3 I148M and environmental factors underscores the need for personalized MASLD prevention and treatment strategies. Targeting both genetic and lifestyle contributors may enhance MASLD management, offering a tailored approach to reducing disease burden.

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-associated liver disease-Global epidemiology

Alcohol-associated liver disease (ALD), as highlighted in this narrative review, is a major public health concern, increasingly impacting global disease burden and premature mortality. In 2019, ALD accounted for the loss of 11 million life-years worldwide. The rising number of deaths and disability-adjusted life-years attributed to ALD, particularly pronounced in the United States, are alarming. Projections suggest that the economic impact of ALD, as seen in the United States, could potentially double by 2040. ALD is increasingly prevalent among younger adults (20-45 y) and has become the leading cause of liver transplantation in both United States and Europe. During the COVID-19 pandemic, the existing trend was further amplified as high-risk drinking patterns coincided with a rise in hospital admissions for alcohol-associated hepatitis and increased ALD-related mortality. The prevalence of ALD is estimated at 3.5% in the general population, 26.0% among hazardous drinkers, and 55.1% among those with alcohol use disorders. Alarmingly, 5-year mortality rates for patients with ALD exceed 50%, with even higher rates in more advanced disease stages. Methodological challenges, such as underreporting, diagnostic difficulties, and variability in registry data quality, complicate the accurate assessment of the impact of ALD. Additionally, the contribution of alcohol to the progression of other liver diseases is often under acknowledged in health care registries, leading to a significant underestimation of its broader implications for liver health. Addressing the growing ALD concern requires robust public health initiatives, heightened awareness, refined diagnostic techniques, and comprehensive epidemiological studies. These measures are vital to tackle the increasing prevalence of ALD and mitigate its extensive impact on individuals and health care systems.

Alcohol Drinking Impacts on Adiposity and Steatotic Liver Disease: Concurrent Effects on Metabolic Pathways and Cardiovascular Risks

PURPOSE OF REVIEW

This integrative search aimed to provide a scoping overview of the relationships between the benefits and harms of alcohol drinking with cardiovascular events as associated to body fat mass and fatty liver diseases, as well as offering critical insights for precision nutrition research and personalized medicine implementation concerning cardiovascular risk management associated to ethanol consumption.

RECENT FINDINGS

Frequent alcohol intake could contribute to a sustained rise in adiposity over time. Body fat distribution patterns (abdominal/gluteus-femoral) and intrahepatic accumulation of lipids have been linked to adverse cardiovascular clinical outcomes depending on ethanol intake. Therefore, there is a need to understand the complex interplay between alcohol consumption, adipose store distribution, metabolic dysfunction-associated steatotic liver disease (MASLD), and cardiovascular events in adult individuals. The current narrative review deals with underconsidered and apparently conflicting benefits concerning the amount of alcohol intake, ranging from abstention to moderation, and highlights the requirements for additional robust methodological studies and trials to interpret undertrained and existing controversies. The conclusion of this review emphasizes the need of newer multifaceted clinical approaches for precision medicine implementation, considering epidemiological strategies and pathophysiological mechanistic. Newer investigations and trials should be derived and performed particularly focusing both on alcohol's objective consequences as putatively mediated by fat deposition, including associated roles in fatty liver disease as well as to differentiate the impact of different levels of alcohol consumption (absence or moderation) concerning cardiovascular risks and accompanying clinical manifestations. Indeed, the threshold for the safe consumption of alcoholic drinks remains to be fully elucidated.

Lifestyle and genetic risk of chronic liver disease in metabolically healthy and unhealthy individuals from the general population

Background & Aims

It is unclear to what extent lifestyle and genetic factors affect the incidence of chronic liver disease (CLD) in the general population and if lifestyle affects CLD independently of underlying cardiometabolic perturbations and genetic predisposition.

Methods

We examined 27,991 men and women aged 44-73 years from the Malmö Diet and Cancer Study recruited between 1991-1996 and followed until the end of 2020 using registry linkage (median follow-up time 25.1 years; 382 incident first-time CLD events). Associations between cardiometabolic factors, polygenic risk scores (PRSs), and lifestyle factors in relation to CLD were examined using multivariable Cox proportional hazards regression models.

Results

The incidence of CLD increased with number of cardiometabolic risk factors (the hazard ratio per each additional cardiometabolic risk factor was 1.33; 95% CI 1.21-1.45; p = 5.1 x 10-10). Two novel PRSs for metabolic dysfunction-associated steatotic liver disease and a PRS for cirrhosis were associated with higher risk of CLD but provided marginal predictive utility on top of other risk factors and compared to the PNPLA3 rs738409 genetic variant. An unhealthy lifestyle (high alcohol intake, current smoking, physical inactivity and unhealthy diet) markedly increased the risk of CLD (hazard ratio 3.97, 95% CI 2.59-6.10). Observed associations between examined lifestyle factors and CLD were largely independent of cardiometabolic perturbations and polygenic risk.

Conclusions

We confirmed the importance of cardiometabolic dysfunction in relation to risk of CLD in the general population. Lifestyle risk factors were shown to be independently associated with CLD and added predictive information on top of cardiometabolic risk factors. Information on the polygenic risk of liver disease does not currently improve the prediction of CLD in the general population.

Impact and implications

This large population-based prospective study suggests largely independent roles of cardiometabolic, lifestyle, and genetic risk factors in the development of chronic liver disease. Findings strengthen the evidence base for a beneficial effect of modification of high-risk lifestyle behaviors in the primary prevention of chronic liver disease in the general population.

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.

Alpha1-antitrypsin deficiency: An updated review

Alpha1-antitrypsin deficiency (AATD) is a rare autosomal recessive disease associated with the homozygous Z variant of the SERPINA1 gene. Clinical expression of AATD, reported 60 years ago associate a severe deficiency, pulmonary emphysema and/or liver fibrosis. Pulmonary emphysema is due to the severe alpha1-antitrypsin deficiency of the ZZ homozygous status and is favored by smoking. Liver fibrosis is due to the ZZ homozygous status and is favored by obesity and excessive chronic alcohol intake, with a risk of liver cancer. Diagnosis is based on serum level and either isoelectric focusing determination of the biochemical phenotype or PCR detection of some variants. SERPINA1 gene sequencing is necessary in case of discrepancies between the results of these tests. No treatment is available for the liver disease in AATD. Although no specific trial has been performed, COPD in AATD should be treated as per COPD recommendations. Based on a randomized clinical trial, augmentation therapy is indicated in non-smoking adults less than 70 years of age with emphysema at chest CT, confirmed homozygous AATD, and FEV1 between 35% and 70% of predicted. In contrast Z heterozygosis (MZ or SZ) brings a risk of lung or liver disease only in association with further risk factors. Early detection, in all patients with COPD and chronic liver disease, is critical for the correct information of Z variant carriers. News ways of correcting the liver production of alpha1-antitrypsin will modify the care of AATD patients.

New Diagnostic and Prognostic Models for the Development of Alcoholic Cirrhosis Based on Genetic Predisposition and Alcohol History

Liver cirrhosis development is a multifactorial process resulting from a combination of environmental and genetic factors. The aim of the study was to develop accurate non-invasive diagnostic and prognostic models for alcoholic cirrhosis. Consecutive subjects with at-risk alcohol intake were retrospectively enrolled (110 cirrhotic patients and 411 non-cirrhotics). At enrollment, the data about lifetime drinking history were collected and all patients were tested for Patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409, Transmembrane 6 Superfamily 2 (TM6SF2) rs58542926, and hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) rs72613567 variants. In cross-sectional analyses, models for the diagnosis of cirrhosis were developed using multivariate logistic regression. A predictive score for cirrhosis development over 24 years was built by evaluating time-dependent AUC curves. The best diagnostic accuracy was demonstrated by the model, which also includes daily alcohol consumption, duration of hazardous alcohol use, and genetic variants, with AUCs of 0.951 (95% CI 0.925-0.977) and 0.887 (95% CI 0.925-0.977) for cirrhosis and compensated cirrhosis, respectively. The predictive model for future cirrhosis development (AUC of 0.836 95% CI: 0.769-0.904) accounted for age at onset of at-risk alcohol consumption and the number of PNPLA3 and HSD17B13 variant alleles. We have developed accurate genetic and alcohol consumption models for the diagnosis of alcoholic cirrhosis and the prediction of its future risk.