A nutrigenetic precision approach for the management of non-alcoholic fatty liver disease

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Protective Effect of FOXO3 rs2802292 G-Allele on Food Intake in a Southern Italian Cohort Affected by MASLD

Background: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is a cluster of conditions characterized by accumulations of fat, metabolic factors such as obesity, diabetes and high cholesterol. MASLD is now the leading cause of chronic liver disease worldwide, with a rapidly increasing trend. We aimed to demonstrate that genetic variants of rs2802292 SNP can influence the development of MASLD even after many years. Methods: We studied 650 participants from the NUTRIHEP cohort, both at baseline (2005-2006) and at first recall (2014-2018), and genotyped rs2802292. The validated European Prospective Investigation into Cancer and Nutrition (EPIC) questionnaire was administered during the visit, and each single food was assigned to one of 33 groups. Results: Associations of food intake at baseline with MASLD were found in the first recall, for each genotype, GG, GT, and TT, and several covariates were used to adjust models. Dressing fats other than olive oil resulted protection against MASLD in GG subjects, whereas seed oil, juices, and spirits resulted in protection against MASLD for GT subjects. An increased risk of MASLD was found for subjects with the TT genotype for white meat intake (OR = 1.018, p = 0.031, 1.002 to 1.035 95% C.I.), ready-to-eat dishes (OR = 1.015, p = 0.033, 1.001 to 1.029 95% C.I.), processed meat (OR = 1.093, p = 0.003, 1.031 to 1.158 95% C.I.), and processed fish (OR = 1.085, p = 0.037, 1.005 to 1.172 95% C.I.). Conclusions: Subjects with the TT genotype had a higher risk of developing MASLD than subjects with other genotypes. A healthier lifestyle is important to counteract liver disease.

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.

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.

A Healthful Plant-Based Diet as an Alternative Dietary Approach in the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease

Plant-based diets (PBDs) are gaining attention as a sustainable and health-conscious alternative for managing various chronic conditions, including metabolic dysfunction-associated steatotic liver disease (MASLD). In the absence of pharmacological treatments, exploring the potential of lifestyle modifications to improve biochemical and pathological outcomes becomes crucial. The adoption of PBDs has demonstrated beneficial effects such as weight control, increased metabolic health and improved coexisting diseases. Nonetheless, challenges persist, including adherence difficulties, ensuring nutritional adequacy, and addressing potential deficiencies. The aim of this review is to provide a comprehensive overview of the impact of PBDs on MASLD, emphasizing the need for tailored dietary interventions with professional support to optimize their effectiveness in preventing and treating metabolic diseases.

The sulfur microbial diet and risk of nonalcoholic fatty liver disease: a prospective gene-diet study from the UK Biobank

BACKGROUND

The gut microbiota is closely related to liver diseases. The dietary pattern associated with sulfur-metabolizing bacteria in stool has been found to influence intestinal health.

OBJECTIVE

We aimed to investigate whether consuming the sulfur microbial diet is associated with nonalcoholic fatty liver disease (NAFLD).

METHODS

We included 143,918 participants of European descent from the UK Biobank. Information on serving sizes used per diet component was recorded by an online 24-h dietary assessment tool (Oxford WebQ). The total sulfur microbial diet score was constructed by summing the product of β-coefficients and corresponding serving sizes. NAFLD was ascertained using hospital inpatient and death records. Cox proportional hazard models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI). Mediation analyses were used to investigate underlying mediators including body mass index, waist circumference, glucose, triglyceride, urate, and C-reactive protein. A polygenic risk score for NAFLD was constructed and stratified to assess whether the association is modified by genetic predisposition.

RESULTS

After a median follow-up of 11.7 y (interquartile range: 11.3-12.5 y), we documented 1540 incident cases of NAFLD. After adjustment for covariates, we observed an overall J-shaped relationship between the sulfur microbial diet and risk of NAFLD. Those in the highest quartile of sulfur microbial diet score had a 46% increased risk of NAFLD [HRQ4vsQ1 (95% CI): 1.46 (1.26, 1.69)]. We also found that this association is partly mediated by metabolic disorders and systemic inflammation. In addition, the positive association was stronger among individuals at higher genetic risk for NAFLD (Pinteraction = 0.044).

CONCLUSIONS

The sulfur microbial diet had adverse associations with incident NAFLD, particularly in those at a higher genetic risk. Our study may provide evidence on the role of sulfur-metabolizing bacteria in the diet-NAFLD association.

Tailored Model of Care for Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), is increasing globally, creating a growing public health concern. However, this disease is often not diagnosed, and accurate data on its epidemiology are limited in many geographical regions, making it challenging to provide proper care and implement effective national plans. To combat the increasing disease burden, screening and diagnosis must reach a significant number of high-risk subjects. Addressing MASLD as a health care challenge requires a multidisciplinary approach involving prevention, diagnosis, treatment, and care, with collaboration between multiple stakeholders in the health care system. This approach must be guided by national and global strategies, to be combined with efficient models of care developed through a bottom-up process. This review article highlights the pillars of the MASLD model of care (MoC), including screening, risk stratification, and establishing a clinical care pathway for management, in addition to discussing the impact of nomenclature change on the proposed MoC.