Exome-wide association study identifies a TM6SF2 variant that confers susceptibility to nonalcoholic fatty liver disease

Disease classification, diagnostic challenges, and evolving clinical trial design in MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) diagnosis and management have evolved rapidly alongside the increasing prevalence of obesity and related complications. Hepatology has expanded its focus beyond late-stage cirrhosis and portal hypertension to earlier, complex MASLD cases in younger patients, necessitating closer collaboration with endocrinology. The renaming of nonalcoholic fatty liver disease (NAFLD) to MASLD reflects its pathophysiology, reduces stigma, and has prompted new research directions. Noninvasive tests such as liver stiffness measurement now play a crucial role in diagnosis, reducing reliance on invasive liver biopsies. However, advanced omics technologies, despite their potential to enhance diagnostic precision and patient stratification, remain underutilized in routine clinical practice. Behavioral factors, including posttraumatic stress disorder (PTSD) and lifestyle choices, influence disease outcomes and must be integrated into patient management strategies. Primary care settings are critical for early screening to prevent progression to advanced disease, yet sizable challenges remain in implementing effective screening protocols. This Review explores these evolving aspects of MASLD diagnosis and management, emphasizing the need for improved diagnostic tools, multidisciplinary collaboration, and holistic care approaches to address existing gaps and ensure comprehensive patient care across all healthcare levels.

Genome-wide enhancer-gene regulatory maps of liver reveal novel regulatory mechanisms underlying NAFLD pathogenesis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) represents the most widespread liver disease globally, ranging from non-alcoholic fatty liver (NAFL) and steatohepatitis (NASH) to fibrosis/cirrhosis, with potential progression to hepatocellular carcinoma (HCC). Genome-wide association studies (GWASs) have identified several single nucleotide polymorphisms (SNPs) associated with NAFLD. However, numerous GWAS signals associated with NAFLD locate in non-coding regions, posing a challenge for interpreting their functional annotation.

RESULTS

In this study, we utilized the Activity-by-Contact (ABC) model to construct the enhancer-gene maps of liver by integrating epigenomic data from 15 liver tissues and cell lines. We constructed the most comprehensive genome-wide regulatory maps of the liver, identifying 543,486 enhancer-gene connections, including 267,857 enhancers and 16,872 target genes. Enrichment analyses revealed that the ABC SNPs are significantly enriched in active chromatin regions and active chromatin state. By combining the ABC regulatory maps and NAFLD GWAS data, we systematically identified ABC SNPs associated with NAFLD risk. Through the functional annotations, such as pathway enrichment and drug-gene interaction analyses, we identified 6 genes (GGT1, ACTG1, SPP1, EPHA2, PROZ and SHMT1) as candidate NAFLD genes, with SHMT1 previously reported. Among the SNPs connected to the candidate genes, the ABC SNP rs2017869 (odds ratio [OR] for the C allele = 1.10, 95% CI = 1.04-1.16, P = 5.97 × 10- 4) had the highest ABC score. According to the ABC maps, rs2017869 links to GGT1, and several drugs targeting this gene, such as liothyronine, showed potential benefits to patients with NAFLD. Furthermore, we identified that another novel gene, EPHA2, may play a crucial role in NAFLD by regulating the GGT levels.

CONCLUSIONS

Our study provides the most comprehensive ABC regulatory maps of the liver to date. This resource offers a valuable reference for identifying regulatory variants and prioritizing susceptibility genes of liver diseases, such as NAFLD.

Beyond obesity: lean metabolic dysfunction-associated steatohepatitis from unveiling molecular pathogenesis to therapeutic advancement

Nonalcoholic fatty liver disease (NAFLD), now known by the name of metabolic dysfunction-associated fatty liver disease (MAFLD), with increased global incidence, has been recognized as a significant metabolic disorder. NAFLD includes a spectrum liver disease from hepatocellular fat accumulation (isolated steatosis) to an advanced form of liver injury known as nonalcoholic steatohepatitis (NASH), which refers to distinct histologic features, including hepatocellular steatosis and injury, necroinflammation, and eventually fibrosis. Nonobese or lean individuals associated with metabolic dysregulation usually demonstrated diverse risk factors compared to obese MAFLD. The presence of normal range body mass index (BMI) and excess visceral adiposity with increased cardiometabolic and renal comorbidities, along with sarcopenia, has been evidenced to be associated with lean MASH. Genetic predispositions accompanying lifestyle and environmental factors contribute to disease initiation and progression. The genetic influence in pathophysiology indicated the significant contributions of the following genes: PNPLA3, TM6SF2, APOB, LIPA, MBOAT7, and HSD17B13, and the impact of their disease-specific variants in the development of obesity-independent MASH. The epigenetic modifications exhibited differential DNA methylation patterns in the genes involved in lipid metabolism, particularly hypomethylation of PEMT. Diet-induced and genetic animal models of lean MASH, including Slc: Wistar/ST rats, PPAR-α, PTEN, and MAT1A knockout mice models, are indicated to be pivotal in the exploration of disease progression and observing the effect of therapeutic interventions. This comprehensive review comprises the molecular and genetic pathophysiology, molecular diagnostics, and therapeutic aspects of lean MASH to enunciate a diagnostic approach that combines detailed clinical phenotyping regarding genomic analysis.

Metabolic dysfunction associated steatotic liver disease is associated with an increased risk of multiple respiratory system diseases

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a significant public health concern. However, the relationship between MAFLD and different types of respiratory diseases is not yet fully understood. In UK Biobank prospective cohort, 11 types of respiratory diseases were identified according to the ICD-10 codes. Cox regression was used to determine the association between MASLD and respiratory disease risk. A total of 393,416 subjects with an average age of 56.6 years were included, MASLD patients account for 34.9%. After fully adjustment for confounding factors, 9 out of 11 respiratory diseases were significantly associated with MASLD, including influenza (hazard ratio (HR): 1.294), pneumonia (HR: 1.258), chronic lower respiratory diseases (HR: 1.297), asthma (HR: 1.222), lung diseases due to external agents (HR: 1.190), interstitial lung diseases (HR: 1.336), diseases of the pleura (HR: 1.175), pulmonary embolism (HR: 1.225), lung and bronchus cancer (HR: 1.212) and respiratory system death (HR: 1.108) (P < 0.05 for all). The risk of respiratory diseases increases with the severity of MASLD assessed by fibrosis score. The relationship between the MASLD phenotype and respiratory diseases is independent of polygenic risk scores and four related risk alleles. These findings emphasize the value of comprehensive prevention of respiratory diseases by targeting MASLD.

Circulating glycerate predicts resilience to fructose-induced hepatic steatosis

Excessive intake of dietary fructose increases the risk of metabolic-dysfunction-associated steatotic liver disease (MASLD), cirrhosis, and cancers. However, what host factors determine disease vulnerability is incompletely understood. Here, we leverage genetically divergent mouse strains, mass spectrometry-based metabolomics, and in vivo isotope tracing, identifying circulating glycerate as a biomarker that predicts resilience to fructose-induced hepatic steatosis in both sexes. We found that the surge of circulating glycerate after an oral fructose provision reflects strong small-intestinal fructose catabolism. Such fructose clearance by the small intestine is linked to a weaker induction of hepatic de novo lipogenesis and steatosis upon chronic fructose exposure across strains. These data indicate the potential utility of an oral fructose tolerance test and circulating glycerate measurements to predict an individual's susceptibility to fructose-elicited steatotic liver and provide personalized dietary recommendations.

Genomic approaches to explore susceptibility and pathogenesis of alcohol use disorder and alcohol-associated liver disease

Excessive alcohol use is a major risk factor for the development of an alcohol use disorder (AUD) and contributes to a wide variety of other medical illnesses, including alcohol-associated liver disease (ALD). Both AUD and ALD are complex and causally interrelated diseases, and multiple factors other than alcohol consumption are implicated in the disease pathogenesis. While the underlying pathophysiology of AUD and ALD is complex, there is substantial evidence for a genetic susceptibility of both diseases. Current genome-wide association studies indicate that the genes associated with clinical AUD only poorly overlap with the genes identified for heavy drinking and, in turn, neither overlap with the genes identified for ALD. Uncovering the main genetic factors will enable us to identify molecular drivers underlying the pathogenesis, discover potential targets for therapy, and implement patient care early in disease progression. In this review, we described multiple genomic approaches and their implications to investigate the susceptibility and pathogenesis of both AUD and ALD. We concluded our review with a discussion of the knowledge gaps and future research on genomic studies in these 2 diseases.

Differences between hepatocellular carcinoma caused by alcohol and other aetiologies

Alcohol-related liver disease is the third leading cause of hepatocellular carcinoma worldwide and the leading cause in Europe. Additionally, the recent definition of metabolic dysfunction-associated steatotic liver disease with increased alcohol intake (MetALD) will enrich this population with a more nuanced phenotype, reflecting recent epidemiological trends. In these patients, the hepatocellular carcinoma diagnosis is often delayed and less frequently detected through screening programmes. Moreover, at the time of diagnosis, patients with alcohol-related hepatocellular carcinoma tend to have a poorer general condition, more severely impaired liver function, and a higher prevalence of comorbidities, leading to increased competitive mortality. However, when hepatocellular carcinoma is diagnosed during surveillance programmes in patients with alcohol-related liver disease or MetALD, the rate of allocation to first-line curative treatments is high (56%) and comparable to that of patients with virus-related hepatocellular carcinoma. As a consequence, the aetiology of the underlying cirrhosis cannot be considered an independent prognostic factor in patients with hepatocellular carcinoma. Instead, prognosis is driven by liver function, general condition, and tumour burden. This underscores the crucial role of early diagnosis through periodic surveillance in patients with alcohol- or MetALD-related cirrhosis.

Psoriasis, metabolic syndrome and methotrexate: Is this association suitable for a new subcategory in steatotic liver disease?

Psoriasis is a prevalent inflammatory disease that shares chronic inflammation pathways with the pathophysiology of metabolic syndrome (MetS), type-2 diabetes mellitus and atherosclerosis. A high prevalence of steatosis and advanced liver fibrosis has been described in psoriasis. The influence of MetS and its compounds, patatin-like phospholipase domain containing 3 and transmembrane 6 superfamily member 2 gene polymorphisms and the cumulative dose of methotrexate (MTX) in the progression of steatotic disease are still under debate. A suitable new classification for psoriasis-related liver disease, under the umbrella of steatotic liver disease (SLD), might be evaluated due to the potential impact of MTX on liver steatosis. Considering the interplay between the MetS, steatosis and MTX, a new definition for this complex disease might be discussed since it is not entirely addressed under the umbrella of SLD and metabolic-dysfunction associated SLD. Hence, shortly, a discussion could be raised on the feasible term "Met-Drug SLD", metabolic and drug-induced SLD, which comprises both metabolic dysfunction and drug-related SLD. This review aims to report the best evidence to accurately classify liver disease in psoriasis, considering the new definition of SLD, allowing appropriate management once it is carefully defined.

Gene-based therapies for steatotic liver disease

Advances in nucleic acid delivery have positioned the liver as a key target for gene therapy, with adeno-associated virus vectors showing long-term effectiveness in treating hemophilia. Steatotic liver disease (SLD), the most common liver condition globally, primarily results from metabolic dysfunction-associated and alcohol-associated liver diseases. In some individuals, SLD progresses from simple steatosis to steatohepatitis, cirrhosis, and eventually hepatocellular carcinoma, driven by a complex interplay of genetic, metabolic, and environmental factors. Genetic variations in various lipid metabolism-related genes, such as patatin-like phospholipase domain-containing protein 3 (PNPLA3), 17β-hydroxysteroid dehydrogenase type 13 (HSD17B13), and mitochondrial amidoxime-reducing component 1 (MTARC1), impact the progression of SLD and offer promising therapeutic targets. This review largely focuses on genes identified through clinical association studies, as they are more likely to be effective and safe for therapeutic intervention. While preclinical research continues to deepen our understanding of genetic factors, early-stage clinical trials involving gene-based SLD therapies, including transient antisense and small-molecule approaches, are helping prioritize therapeutic targets. Meanwhile, hepatocyte gene editing technologies are advancing rapidly, offering alternatives to transient methods. As such, gene-based therapies show significant potential for preventing the progression of SLD and enhancing long-term liver health.

Genetic Risk Phenotypes for Type 2 Diabetes Differ with Ancestry in US Adults with Diabetes and Overweight/Obesity

BACKGROUND

Type 2 diabetes (T2D) risk is higher among non-Hispanic black (NHB) and Hispanic individuals, for reasons that are unclear.

AIMS

With this cross-sectional study, we tested the hypothesis that racial disparities in T2D prevalence can be partially traced to heterogeneity in etiology, as indicated by genetic subtypes that reflect distinct T2D phenotypes.

METHODS

Using a diverse sample of 361 US adults with T2D (69.5% women; 34.1% NHB; 13.9% Hispanic), we derived genetic risk scores (GRS) representing five distinct T2D pathophysiological pathways from 94 loci: β-cell, proinsulin, obesity, lipodystrophy, and liver/lipid. Genetic predisposition for insulin resistance (IR) was also assessed using a 52-SNP IR risk score.

RESULTS

The β-cell and proinsulin scores (as median [IQR]) were higher among NHB participants relative to NHW and Hispanics (β-cell GRS [NHB, 0.842(0.784-0.887) vs. NHW, 0.762(0.702-0.835) and Hispanic, 0.772(0.717-0.848)]); proinsulin GRS (NHB, 1.006[0.973-1.070] vs. NHW, 0.969[0.853-1.044] and Hispanic, 0.976[0.901-1.048]), whereas the liver/lipid and 52-SNP IR scores were higher in both NHB and Hispanic participants versus NHW (liver/lipid GRS [NHB, 1.09(0.78-1.18) and Hispanic, 0.895(0.736-1.227) vs. NHW, 0.794(0.666-1.157)]); 52-SNP IR GRS (NHB, 0.0095[0.009-0.010] and Hispanic, 0.0096 [0.0092-0.0101] vs. NHW, 0.0090[0.0084-0.0095]).

CONCLUSIONS

Impaired β-cell function may underlie T2D etiology more profoundly in NHB, whereas hepatic dysfunction, lipid metabolism abnormalities, and genetic IR contribute to T2D etiology to a greater degree in both NHB and Hispanics. Further validation of these findings may form the basis for a personalized medicine approach to prevention and treatment of T2D.

Downregulation of the MARC1 p.A165 risk allele reduces hepatocyte lipid content by increasing beta-oxidation

BACKGROUND/AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global epidemic. The disease has a strong genetic component, and a common missense variant (rs2642438) in the mitochondrial amidoxime-reducing component 1 (MARC1) gene confers protection against its onset and severity. However, there are contrasting results regarding the mechanisms that promote this protection.

METHODS

We downregulated MARC1 in primary human hepatocytes (PHHs) using short interfering RNA (siRNA). We measured neutral lipid content by Oil-Red O staining and fatty acid oxidation by radiolabeled tracers. We also performed RNA-sequencing and proteomic analysis using LC-MS. Additionally, we analyzed data from 239,075 participants from the UK Biobank.

RESULTS

Downregulation of MARC1 reduced neutral lipid content in PHHs homozygous for the wild type (p.A165, risk), but not for the mutant (p.T165, protective), allele. We found that this reduction was mediated by increased fatty acid utilization via β-oxidation. Consistent with these results, we found that the levels of 3-hydroxybutyrate, a by-product of β-oxidation, were higher in carriers of the rs2642438 minor allele among samples from the UK biobank, indicating higher β-oxidation in these individuals. Moreover, downregulation of the MARC1 p.A165 variant resulted in a more favorable phenotype by reducing ferroptosis and reactive oxygen species levels.

CONCLUSION

MARC1 downregulation in carriers of the risk allele results in lower hepatocyte neutral lipids content due to higher β-oxidation, while upregulating beneficial pathways involved in cell survival.

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.

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.

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.

Association between single nucleotide polymorphisms in PNPLA3, TM6SF2 and MBOAT7 genes and markers of cancer aggressiveness in a Sri Lankan NASH-related HCC cohort

BACKGROUND

Single nucleotide polymorphisms (SNPs) in patatin-like phospholipase domain-containing protein 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2) and membrane bound O-acyltransferase domain containing 7 (MBOAT7) genes were reported to be strongly associated with non-alcoholic fatty liver disease (NAFLD) pathogenicity among different populations. We investigated whether these SNPs are associated with prognostic factors and genetic biomarkers of non-alcoholic steatohepatitis (NASH)-related hepatocellular carcinoma (HCC) in the Sri Lankan context.

METHODS

We conducted an exploratory study to evaluate the prevalence of five SNPs (PNPLA3 rs738409, PNPLA3 rs2281135, PNPLA3 rs2294918, TM6SF2 rs58542926 and MBOAT7 rs641738) as genetic risk factors for NASH-HCC pathogenicity. We genotyped 48 NASH-HCC patient samples collected at a clinical setting using a minisequencing method. Impact of each SNP with tumor prognostic factors such as nodularity, tumor size and AFP (alpha-feto protein) level was analyzed using chi square test. We also analyzed the expression of micro RNA-122 (miR-122) in serum and leukocyte telomere length via quantitative real-time PCR. Associations between each SNP with micro RNA-122 (miR-122) expression level and leukocyte telomere length of NASH-HCC patients were analyzed using one-way analysis of variance (ANOVA) test and independent t test. Relationships among tested SNPs and some well-established HCC risk factors such as age, BMI, gender, diabetes status and the cirrhotic stage were also analyzed using chi square test, independent t-test and One-way ANOVA test.

RESULTS

Our analyses demonstrated significant associations between PNPLA3 rs2281135 variant and tumor nodularity. Also, PNPLA3 rs2281135 and PNPLA3 rs2294918 variants were significantly associated with miR-122 expression levels of NASH-HCC patients. Further, age and body mass index (BMI) were significantly associated with PNPLA3 rs2281135 variant in our study cohort.

CONCLUSION

We found that in the Sri Lankan NASH-related HCC cohort, some PNPLA3 variants (rs2281135 and rs2294918) correlate with tumor nodularity, higher miR-122 expression, and distinct demographic features such as age and BMI. Our work highlights the role of specific SNPs in tumor aggressiveness, contributing to the precision screening for HCC in NASH patients.

A Comprehensive Review of Metabolic Dysfunction-Associated Steatotic Liver Disease: Its Mechanistic Development Focusing on Methylglyoxal and Counterbalancing Treatment Strategies

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a multifactorial disorder characterized by excessive lipid accumulation in the liver which dysregulates the organ's function. The key contributor to MASLD development is insulin resistance (IR) which affects many organs (including adipose tissue, skeletal muscles, and the liver), whereas the molecular background is associated with oxidative, nitrosative, and carbonyl stress. Among molecules responsible for carbonyl stress effects, methylglyoxal (MGO) seems to play a major pathological function. MGO-a by-product of glycolysis, fructolysis, and lipolysis (from glycerol and fatty acids-derived ketone bodies)-is implicated in hyperglycemia, hyperlipidemia, obesity, type 2 diabetes, hypertension, and cardiovascular diseases. Its causative effect in the stimulation of prooxidative and proinflammatory pathways has been well documented. Since metabolic dysregulation leading to these pathologies promotes MASLD, the role of MGO in MASLD is addressed in this review. Potential MGO participation in the mechanism of MASLD development is discussed in regard to its role in different signaling routes leading to pathological events accelerating the disorder. Moreover, treatment strategies including approved and potential therapies in MASLD are overviewed and discussed in this review. Among them, medications aimed at attenuating MGO-induced pathological processes are addressed.

Metabolic dysfunction-associated steatotic liver disease in adults

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the umbrella term that comprises metabolic dysfunction-associated steatotic liver, or isolated hepatic steatosis, through to metabolic dysfunction-associated steatohepatitis, the progressive necroinflammatory disease form that can progress to fibrosis, cirrhosis and hepatocellular carcinoma. MASLD is estimated to affect more than one-third of adults worldwide. MASLD is closely associated with insulin resistance, obesity, gut microbial dysbiosis and genetic risk factors. The obesity epidemic and the growing prevalence of type 2 diabetes mellitus greatly contribute to the increasing burden of MASLD. The treatment and prevention of major metabolic comorbidities such as type 2 diabetes mellitus and obesity will probably slow the growth of MASLD. In 2023, the field decided on a new nomenclature and agreed on a set of research and action priorities, and in 2024, the US FDA approved the first drug, resmetirom, for the treatment of non-cirrhotic metabolic dysfunction-associated steatohepatitis with moderate to advanced fibrosis. Reliable, validated biomarkers that can replace histology for patient selection and primary end points in MASH trials will greatly accelerate the drug development process. Additionally, noninvasive tests that can reliably determine treatment response or predict response to therapy are warranted. Sustained efforts are required to combat the burden of MASLD by tackling metabolic risk factors, improving risk stratification and linkage to care, and increasing access to therapeutic agents and non-pharmaceutical interventions.

The biogenesis and transport of triglyceride-rich lipoproteins

Triglyceride-rich lipoproteins (TRLs) play essential roles in human health and disease by transporting bulk lipids into the circulation. This review summarizes the fundamental mechanisms and diverse factors governing lipoprotein production, secretion, and regulation. Emphasizing the broader implications for human health, we outline the intricate landscape of lipoprotein research and highlight the potential coordination between the biogenesis and transport of TRLs in physiology, particularly the unexpected coupling of metabolic enzymes and transport machineries. Challenges and opportunities in lipoprotein biology with respect to inherited diseases and viral infections are also discussed. Further characterization of the biogenesis and transport of TRLs will advance both basic research in lipid biology and translational medicine for metabolic diseases.

Pharmacological treatment for metabolic dysfunction-associated steatotic liver disease and related disorders: Current and emerging therapeutic options

Metabolic dysfunction-associated steatotic liver disease (MASLD; formerly known as nonalcoholic fatty liver disease) is a chronic liver disease affecting over a billion individuals worldwide. MASLD can gradually develop into more severe liver pathologies, including metabolic dysfunction-associated steatohepatitis (MASH), cirrhosis, and liver malignancy. Notably, although being a global health problem, there are very limited therapeutic options against MASLD and its related diseases. While a thyroid hormone receptor agonist (resmetirom) is recently approved for MASH treatment, other efforts to control these diseases remain unsatisfactory. Given the projected rise in MASLD and MASH incidence, it is urgent to develop novel and effective therapeutic strategies against these prevalent liver diseases. In this article, the pathogenic mechanisms of MASLD and MASH, including insulin resistance, dysregulated nuclear receptor signaling, and genetic risk factors (eg, patatin-like phospholipase domain-containing 3 and hydroxysteroid 17-β dehydrogenase-13), are introduced. Various therapeutic interventions against MASH are then explored, including approved medication (resmetirom), drugs that are currently in clinical trials (eg, glucagon-like peptide 1 receptor agonist, fibroblast growth factor 21 analog, and PPAR agonist), and those failed in previous trials (eg, obeticholic acid and stearoyl-CoA desaturase 1 antagonist). Moreover, given that the role of gut microbes in MASLD is increasingly acknowledged, alterations in the gut microbiota and microbial mechanisms in MASLD development are elucidated. Therapeutic approaches that target the gut microbiota (eg, dietary intervention and probiotics) against MASLD and related diseases are further explored. With better understanding of the multifaceted pathogenic mechanisms, the development of innovative therapeutics that target the root causes of MASLD and MASH is greatly facilitated. The possibility of alleviating MASH and achieving better patient outcomes is within reach. SIGNIFICANCE STATEMENT: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease worldwide, and it can progress to more severe pathologies, including steatohepatitis, cirrhosis, and liver cancer. Better understanding of the pathogenic mechanisms of these diseases has facilitated the development of innovative therapeutic strategies. Moreover, increasing evidence has illustrated the crucial role of gut microbiota in the pathogenesis of MASLD and related diseases. It may be clinically feasible to target gut microbes to alleviate MASLD in the future.

Integrative metabolism in MASLD and MASH: Pathophysiology and emerging mechanisms

The liver acts as a central metabolic hub, integrating signals from the gastrointestinal tract and adipose tissue to regulate carbohydrate, lipid, and amino acid metabolism. Gut-derived metabolites, such as acetate and ethanol and non-esterified fatty acids from white adipose tissue, influence hepatic processes, which rely on mitochondrial function to maintain systemic energy balance. Metabolic dysregulation caused by obesity, insulin resistance, and type 2 diabetes disrupts these pathways, leading to metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH). In this review, we explore the metabolic fluxes within the gut-adipose tissue-liver axis, focusing on the pivotal role of de novo lipogenesis, dietary substrates like glucose and fructose, and changes in mitochondrial function during MASLD progression. We also highlight the contributions of white adipose tissue insulin resistance and impaired mitochondrial dynamics to hepatic lipid accumulation. Further understanding how the interplay between substrate flux from the gastro-intestinal tract integrates with adipose tissue and intersects with structural and functional alterations to liver mitochondria will be important to identify novel therapeutic targets and advance the treatment of MASLD and MASH.

Linking Cardiovascular Disease and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): The Role of Cardiometabolic Drugs in MASLD Treatment

The link between cardiovascular disease (CVD) and metabolic dysfunction-associated steatotic liver disease (MASLD) is well-established at both the epidemiological and pathophysiological levels. Among the common pathophysiological mechanisms involved in the development and progression of both diseases, oxidative stress and inflammation, insulin resistance, lipid metabolism deterioration, hepatokines, and gut dysbiosis along with genetic factors have been recognized to play a pivotal role. Pharmacologic interventions with drugs targeting common modifiable cardiometabolic risk factors, such as T2DM, dyslipidemia, and hypertension, are a reasonable strategy to prevent CVD development and progression of MASLD. Recently, a novel drug for metabolic dysfunction-associated steatohepatitis (MASH), resmetirom, has shown positive effects regarding CVD risk, opening new opportunities for the therapeutic approach of MASLD and CVD. This review provides current knowledge on the epidemiologic association of MASLD to CVD morbidity and mortality and enlightens the possible underlying pathophysiologic mechanisms linking MASLD with CVD. The role of cardiometabolic drugs such as anti-hypertensive drugs, hypolipidemic agents, glucose-lowering medications, acetylsalicylic acid, and the thyroid hormone receptor-beta agonist in the progression of MASLD is also discussed. Metformin failed to prove beneficial effects in MASLD progression. Studies on the administration of thiazolinediones in MASLD suggest effectiveness in improving steatosis, steatohepatitis, and fibrosis, while newer categories of glucose-lowering agents such as GLP-1Ra and SGLT-2i are currently being tested for their efficacy across the whole spectrum of MASLD. Statins alone or in combination with ezetimibe have yielded promising results. The conduction of long-duration, large, high-quality, randomized-controlled trials aiming to assess by biopsy the efficacy of cardiometabolic drugs to reverse MASLD progression is of great importance.

Functional compartmentalization of hepatic mitochondrial subpopulations during MASH progression

The role of peridroplet mitochondria (PDM) in diseased liver, such as during the progression of metabolic dysfunction-associated steatohepatitis (MASH), remains unknown. We isolated hepatic cytoplasmic mitochondria (CM) and PDM from a mouse model of diet-induced MASLD/MASH to characterize their functions from simple steatosis to advanced MASH, using chow-fed mice as controls. Our findings show an inverse relationship between hepatic CM and PDM levels from healthy to steatosis to advanced MASH. Proteomics analysis revealed these two mitochondrial populations are compositionally and functionally distinct. We found that hepatic PDM are more bioenergetically active than CM, with higher pyruvate oxidation capacity in both healthy and diseased liver. Higher respiration capacity of PDM was associated with elevated OXPHOS protein complexes and increased TCA cycle flux. In contrast, CM showed higher fatty acid oxidation capacity with MASH progression. Transmission electron microscopy revealed larger and elongated mitochondria during healthy and early steatosis, which appeared small and fragmented during MASH progression. These changes coincided with higher MFN2 protein levels in hepatic PDM and higher DRP1 protein levels in hepatic CM. These findings highlight the distinct roles of hepatic CM and PDM in MASLD progression towards MASH.

Unraveling Metabolic Dysfunction-Associated Steatotic Liver Disease Through the Use of Omics Technologies

Non-alcoholic fatty liver disease (NAFLD), now referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), is the most prevalent liver disorder globally, linked to obesity, type 2 diabetes, and cardiovascular risk. Understanding its potential progression from simple steatosis to cirrhosis and hepatocellular carcinoma (HCC) is crucial for patient management and treatment strategies. The disease's complexity requires innovative approaches for early detection and personalized care. Omics technologies-such as genomics, transcriptomics, proteomics, metabolomics, and exposomics-are revolutionizing the study of MASLD. These high-throughput techniques allow for a deeper exploration of the molecular mechanisms driving disease progression. Genomics can identify genetic predispositions, whilst transcriptomics and proteomics reveal changes in gene expression and protein profiles during disease evolution. Metabolomics offers insights into the metabolic alterations associated with MASLD, while exposomics links environmental exposures to MASLD progression and pathology. By integrating data from various omics platforms, researchers can map out the intricate biochemical pathways involved in liver disease progression. This review discusses the roles of omics technologies in enhancing the understanding of disease progression and highlights potential diagnostic and therapeutic targets within the MASLD spectrum, emphasizing the need for non-invasive tools in disease staging and treatment development.

VLDL triglycerides and cholesterol in non-alcoholic fatty liver disease and myocardial infarction

BACKGROUND AND AIMS

Myocardial infarction is a leading cause of death in individuals with non-alcoholic fatty liver disease (NAFLD). The two diseases share elevated very low-density lipoproteins (VLDL) carrying both triglycerides and cholesterol; however, in NAFLD mainly triglycerides accumulate in liver cells while in myocardial infarction mainly cholesterol accumulates in the atherosclerotic plaque. We hypothesized that VLDL triglycerides preferentially associate with risk of NAFLD, while VLDL cholesterol preferentially associates with risk of myocardial infarction.

METHODS

We examined 25,428 individuals without clinically diagnosed NAFLD or myocardial infarction at baseline, nested within 109,776 individuals from the prospective Copenhagen General Population Study and followed these individuals for a mean of 10 years. VLDL triglycerides, VLDL cholesterol, and low-density lipoprotein (LDL) cholesterol were determined using nuclear magnetic resonance spectrometry.

RESULTS

Continuously higher VLDL triglycerides were associated with continuously higher risk of NAFLD; however, this was not the case for VLDL cholesterol, LDL cholesterol, or apolipoprotein B. In contrast, continuously higher VLDL cholesterol, LDL cholesterol, and plasma apolipoprotein B were all associated with continuously higher risk of myocardial infarction. Compared to individuals with both VLDL triglycerides and VLDL cholesterol ≤66th percentile, the hazard ratios for NAFLD in individuals with VLDL triglycerides >66th percentile were 1.61(95 % confidence intervals:1.25-2.06) at high VLDL cholesterol and 1.41(0.90-2.21) at low VLDL cholesterol. Corresponding hazard ratios for myocardial infarction in individuals with VLDL cholesterol >66th percentile were 1.51(1.36-1.67) at high VLDL triglycerides and 1.42(1.18-1.69) at low VLDL triglycerides.

CONCLUSIONS

VLDL triglycerides predominated in NAFLD while VLDL cholesterol predominated in myocardial infarction; however, VLDL cholesterol was also elevated slightly in NAFLD while VLDL triglycerides was also elevated in myocardial infarction.

Precision medicine and nucleotide-based therapeutics to treat steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a complex multifactorial disease and becoming the leading cause of liver-related morbidity and mortality. MASLD spans from isolated steatosis to metabolic dysfunction-associated steatohepatitis (MASH), that may progress to cirrhosis and hepatocellular carcinoma (HCC). Genetic, metabolic, and environmental factors strongly contribute to the heterogeneity of MASLD. Lifestyle intervention and weight loss represent a viable treatment for MASLD. Moreover, Resmetirom, a thyroid hormone beta receptor agonist, has recently been approved for MASLD treatment. However, most individuals treated did not respond to this therapeutic, suggesting the need for a more tailored approach to treat MASLD. Oligonucleotide-based therapies, namely small-interfering RNA (siRNA) and antisense oligonucleotide (ASO), have been recently developed to tackle MASLD by reducing the expression of genes influencing MASH progression, such as PNPLA3 and HSD17B13. Here, we review the latest progress made in the synthesis and development of oligonucleotide-based agents targeting genetic determinants of MASH.

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.

Proteome-wide association studies for blood lipids and comparison with transcriptome-wide association studies

Blood lipid traits are treatable and heritable risk factors for heart disease, a leading cause of mortality worldwide. Although genome-wide association studies (GWASs) have discovered hundreds of variants associated with lipids in humans, most of the causal mechanisms of lipids remain unknown. To better understand the biological processes underlying lipid metabolism, we investigated the associations of plasma protein levels with total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol in blood. We trained protein prediction models based on samples in the Multi-Ethnic Study of Atherosclerosis (MESA) and applied them to conduct proteome-wide association studies (PWASs) for lipids using the Global Lipids Genetics Consortium (GLGC) data. Of the 749 proteins tested, 42 were significantly associated with at least one lipid trait. Furthermore, we performed transcriptome-wide association studies (TWASs) for lipids using 9,714 gene expression prediction models trained on samples from peripheral blood mononuclear cells (PBMCs) in MESA and 49 tissues in the Genotype-Tissue Expression (GTEx) project. We found that although PWASs and TWASs can show different directions of associations in an individual gene, 40 out of 49 tissues showed a positive correlation between PWAS and TWAS signed p values across all the genes, which suggests high-level consistency between proteome-lipid associations and transcriptome-lipid associations.

Identification of Interactive Genetic Loci Linked to Insulin Resistance in Metabolic Syndrome-An Update

Metabolic syndrome is a metabolic disorder characterized by hypertension, dyslipidemia, impaired glucose tolerance, and abdominal obesity. Impaired insulin action or insulin resistance initiates metabolic syndrome. The prevalence of insulin resistance is increasing all over the world. Insulin resistance results in the defective metabolism of carbohydrates and lipids, in addition to low-grade chronic inflammation. Insulin resistance is associated with metabolic syndrome, which is a risk factor for a number of pathological conditions, such as Type 2 diabetes (T2D), cardiovascular disease (CVD), nonalcoholic fatty liver disease (NAFLD), and polycystic ovarian syndrome (PCOS). Genome-wide association studies have increased our understanding of many loci linked to these diseases and others. In this review, we discuss insulin resistance and its contribution to metabolic syndrome and these diseases. We also discuss the genetic loci associated with them. Genetic testing is invaluable in the identification and stratification of susceptible populations and/or individuals. After susceptible individuals and/or populations have been identified via genetic testing or screening, lifestyle modifications such as regular exercise, weight loss, a healthy diet, and smoking cessation can reduce or prevent metabolic syndrome and its associated pathologies.

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.

Deep metabolic phenotyping of humans with protein-altering variants in TM6SF2 using a genome-first approach

Background & Aim

An unbiased genome-first approach can expand the molecular understanding of specific genes in disease-agnostic biobanks for deeper phenotyping. TM6SF2 represents a good candidate for this approach due to its known association with steatotic liver disease (SLD).

Methods

We screened participants with whole-exome sequences in the Penn Medicine Biobank (PMBB, n >40,000) and the UK Biobank (UKB, n >200,000) for protein-altering variants in TM6SF2 and evaluated their association with liver phenotypes and clinical outcomes.

Results

Missense variants in TM6SF2 (E167K, L156P, P216L) were associated with an increased risk of clinically diagnosed and imaging-proven steatosis, independent of the PNPLA3 I48M risk allele and hepatitis B/C (p <0.001). E167K homozygotes had significantly increased risk of SLD (odds ratio [OR] 5.38, p <0.001), steatohepatitis (OR 5.76, p <0.05) and hepatocellular carcinoma (OR 11.22, p <0.0001), while heterozygous carriers of L156P and P216L were also at an increased risk of steatohepatitis. In addition, carriers of E167K are at a 3-fold increased risk of at-risk MASH (OR 2.75, p <0.001). CT-derived liver fat scores were higher in E167K and L156P in an allele-dose manner (p <0.05). This corresponded with the UKB nuclear magnetic resonance-derived lipidomic analyses (n = 105,348), revealing all carriers to exhibit lower total cholesterol, triglycerides and total choline. In silico predictions suggested that these missense variants cause structural disruptions in the EXPERA domain, leading to reduced protein function. This hypothesis was supported by the association of rare loss-of-function variants in TM6SF2 with an increased risk of SLD (OR 4.9, p <0.05), primarily driven by a novel rare stop-gain variant (W35X) with the same directionality.

Conclusion

The functional genetic study of protein-altering variants provides insights on the association between loss of TM6SF2 function and SLD and provides the basis for future mechanistic studies.

Impact and implications

The genome-first approach expands insights into genetic risk factors for steatotic liver disease with TM6SF2 being a focal point due to its known association with plasma lipid traits. Our findings validated the association of two missense variants (E167K and L156P) with increased risk of hepatic steatosis on CT and MRI scans, as well as the risk of clinically diagnosed hepatocellular carcinoma independent of the common PNPLA3 I48M risk variant. Notably, we also identified a predicted deleterious missense variant (P216L) linked to steatotic risk and demonstrated that an aggregated gene burden of rare putative loss-of-function variants was associated with the risk of hepatic steatosis. Combined, this study sets the stage for future mechanistic investigations into the functional consequences of TM6SF2 variants in metabolic dysfunction-associated steatotic liver disease.

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.

Intestinal TM6SF2 protects against metabolic dysfunction-associated steatohepatitis through the gut-liver axis

Transmembrane-6 superfamily member 2 (TM6SF2) regulates hepatic fat metabolism and is associated with metabolic dysfunction-associated steatohepatitis (MASH). TM6SF2 genetic variants are associated with steatotic liver disease. The pathogenesis of MASH involves genetic factors and gut microbiota alteration, yet the role of host-microbe interactions in MASH development remains unclear. Here, we discover that mice with intestinal epithelial cell-specific knockout of Tm6sf2 (Tm6sf2ΔIEC) develop MASH, accompanied by impaired intestinal barrier and microbial dysbiosis. Transplanting stools from Tm6sf2ΔIEC mice induces steatohepatitis in germ-free recipient mice, whereas MASH is alleviated in Tm6sf2ΔIEC mice co-housed with wild-type mice. Mechanistically, Tm6sf2-deficient intestinal cells secrete more free fatty acids by interacting with fatty acid-binding protein 5 to induce intestinal barrier dysfunction, enrichment of pathobionts, and elevation of lysophosphatidic acid (LPA) levels. LPA is translocated from the gut to the liver, contributing to lipid accumulation and inflammation. Pharmacological inhibition of the LPA receptor suppresses MASH in both Tm6sf2ΔIEC and wild-type mice. Hence, modulating microbiota or blocking the LPA receptor is a potential therapeutic strategy in TM6SF2 deficiency-induced MASH.

Diverting hepatic lipid fluxes with lifestyles revision and pharmacological interventions as a strategy to tackle steatotic liver disease (SLD) and hepatocellular carcinoma (HCC)

Steatotic liver disease (SLD) and Hepatocellular Carcinoma (HCC) are characterised by a substantial rewiring of lipid fluxes caused by systemic metabolic unbalances and/or disrupted intracellular metabolic pathways. SLD is a direct consequence of the interaction between genetic predisposition and a chronic positive energy balance affecting whole-body energy homeostasis and the function of metabolically-competent organs. In this review, we discuss how the impairment of the cross-talk between peripheral organs and the liver stalls glucose and lipid metabolism, leading to unbalances in hepatic lipid fluxes that promote hepatic fat accumulation. We also describe how prolonged metabolic stress builds up toxic lipid species in the liver, and how lipotoxicity and metabolic disturbances drive disease progression by promoting a chronic activation of wound healing, leading to fibrosis and HCC. Last, we provide a critical overview of current state of the art (pre-clinical and clinical evidence) regarding mechanisms of action and therapeutic efficacy of candidate SLD treatment options, and their potential to interfere with SLD/HCC pathophysiology by diverting lipids away from the liver therefore improving metabolic health.

Mechanisms and therapeutic targets of mitochondria in the progression of metabolic dysfunction-associated steatotic liver disease

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) includes liver disease processes from simple fatty liver to nonalcoholic steatohepatitis, which may progress to liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). As the incidence of HCC derived from viral hepatitis decreases, MASLD has emerged as a significant health threat, driven by lifestyle changes and rising obesity rates among patients. The pathogenesis of MASLD is complex, involving factors such as insulin resistance, gut microbiota imbalance, and genetic and epigenetic factors. In recent years, the role of mitochondrial dysfunction in MASLD has gained significant attention, involving β-oxidation imbalance, oxidative stress increase, mitophagy defects, and mitochondrial DNA (mtDNA) mutations. This article reviews the pathophysiological mechanisms of mitochondrial dysfunction in MASLD, diagnostic methods, and potential therapeutic strategies. By synthesizing current research findings, the review aims to highlight the critical role of mitochondrial dysfunction as a target for future diagnostic and therapeutic interventions. This focus could pave the way for innovative clinical strategies, ultimately improving treatment options and patient prognosis in MASLD.

Immunological dynamics in MASH: from landscape analysis to therapeutic intervention

Metabolic dysfunction-associated steatohepatitis (MASH), previously known as nonalcoholic steatohepatitis (NASH), is a multifaceted liver disease characterized by inflammation and fibrosis that develops from simple steatosis. Immune and inflammatory pathways have a central role in the pathogenesis of MASH, yet, how to target immune pathways to treat MASH remains perplexed. This review emphasizes the intricate role that immune cells play in the etiology and pathophysiology of MASH and highlights their significance as targets for therapeutic approaches. It discusses both current strategies and novel therapies aimed at modulating the immune response in MASH. It also highlights challenges in liver-specific drug delivery, potential off-target effects, and difficulties in targeting diverse immune cell populations within the liver. This review is a comprehensive resource that integrates current knowledge with future perspectives in the evolving field of MASH, with the goal of driving forward progress in medical therapies designed to treat this complex liver disease.

Associations between metabolic dysfunction-associated fatty liver disease and atherosclerotic cardiovascular disease

Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic syndrome and remains a major global health burden. The increased prevalence of obesity and type 2 diabetes mellitus (T2DM) worldwide has contributed to the rising incidence of NAFLD. It is widely believed that atherosclerotic cardiovascular disease (ASCVD) is associated with NAFLD. In the past decade, the clinical implications of NAFLD have gone beyond liver-related morbidity and mortality, with a majority of patient deaths attributed to malignancy, coronary heart disease (CHD), and other cardiovascular (CVD) complications. To better define fatty liver disease associated with metabolic disorders, experts proposed a new term in 2020 - metabolic dysfunction associated with fatty liver disease (MAFLD). Along with this new designation, updated diagnostic criteria were introduced, resulting in some differentiation between NAFLD and MAFLD patient populations, although there is overlap. The aim of this review is to explore the relationship between MAFLD and ASCVD based on the new definitions and diagnostic criteria, while briefly discussing potential mechanisms underlying cardiovascular disease in patients with MAFLD.

Combination of risk alleles of PNPLA3, TM6SF2, and HSD17B13 of donors can predict recurrence of steatotic liver disease after liver transplantation

AIMS

This study aimed to identify the genetic risk factors from donors or recipients that contribute to postliver transplantation (LT) steatotic liver disease (SLD), focusing on the genetic risk score (GRS) based on single nucleotide polymorphisms (SNPs) in SLD patients.

METHODS

This retrospective study included 55 Japanese SLD recipients and their respective donors. Genotyping of PNPLA3, TM6SF2, and HSD17B13 was undertaken, and the combined GRS was calculated. The relationship between the GRS and the incidence of posttransplant SLD was also evaluated.

RESULTS

The SLD recipients had a high prevalence of post-LT graft steatosis/steatohepatitis (76.4% and 58.2%, respectively). Although the recipients had a high frequency of risk alleles, there was no relationship between the number of risk alleles for each SNP and the incidence of posttransplant SLD. In contrast, an increased number of risk alleles for any SNP in the donor was correlated with high incidence rates of both post-LT steatosis and steatohepatitis. A multivariable analysis showed that a high donor GRS was an independent risk factor for graft steatosis (odds ratio 8.77; 95% CI, 1.94-52.94; p = 0.009). Similarly, a high donor GRS was an independent risk factor (odds ratio 6.76; 95% CI, 1.84-30.78; p = 0.007) for post-LT graft steatohepatitis.

CONCLUSIONS

Donor risk alleles of PNPLA3, TM6SF2, and HSD17B13, rather than recipient risk alleles, have been implicated in the development of posttransplant SLD. The combination of these donor risk alleles into a GRS could predict the development of posttransplant SLD.

Management of non-alcoholic fatty liver disease-associated hepatocellular carcinoma

In recent years, with the decline in HBV and HCV infections, there has been a corresponding reduction in both the morbidity and mortality of virus-associated HCC. Nevertheless, rising living standards, coupled with the increasing prevalence of metabolic disorders like diabetes and obesity, have led to a rapid surge in non-alcoholic fatty liver disease-associated hepatocellular carcinoma (NAFLD-HCC) incidence. The mechanisms underlying the progression from NAFLD to NAFLD-HCC are multifaceted and remain incompletely understood. Current research suggests that genetic predisposition, metabolic dysregulation, lipotoxicity, oxidative stress, and inflammation are key contributing factors. Given the complexity of these mechanisms and the frequent occurrence of metabolic comorbidities like type 2 diabetes mellitus (T2DM) and cardiovascular disease in NAFLD-HCC patients, there is a pressing need for tailored therapeutic strategies, along with novel prevention, monitoring, and treatment approaches that are personalized to the patient's pathophysiology. Due to the limited depth of research, incomplete understanding of pathogenesis, and insufficient clinical data on NAFLD-HCC treatment, current therapeutic approaches largely rely on tumor staging. In this review, we synthesize current research on the pathogenesis, surveillance, diagnosis, treatment, and prevention of NAFLD-HCC, and offer perspectives for future studies, particularly regarding its underlying mechanisms.

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.

Diabetes as a risk factor for MASH progression

Non-alcoholic (now: metabolic) steatohepatitis (MASH) is the progressive inflammatory form of metabolic dysfunction-associated steatotic liver disease (MASLD), which often coexists and mutually interacts with type 2 diabetes (T2D), resulting in worse hepatic and cardiovascular outcomes. Understanding the intricate mechanisms of diabetes-related MASH progression is crucial for effective therapeutic strategies. This review delineates the multifaceted pathways involved in this interplay and explores potential therapeutic implications. The synergy between adipose tissue, gut microbiota, and hepatic alterations plays a pivotal role in disease progression. Adipose tissue dysfunction, particularly in the visceral depot, coupled with dysbiosis in the gut microbiota, exacerbates hepatic injury and insulin resistance. Hepatic lipid accumulation, oxidative stress, and endoplasmic reticulum stress further potentiate inflammation and fibrosis, contributing to disease severity. Dietary modification with weight reduction and exercise prove crucial in managing T2D-related MASH. Additionally, various well-known but also novel anti-hyperglycemic medications exhibit potential in reducing liver lipid content and, in some cases, improving MASH histology. Therapies targeting incretin receptors show promise in managing T2D-related MASH, while thyroid hormone receptor-β agonism has proven effective as a treatment of MASH and fibrosis.

Steatotic liver disease in the context of hematological malignancies and anti-neoplastic chemotherapy

The rising prevalence of obesity-related illnesses, such as metabolic steatotic liver disease (MASLD), represents a significant global public health concern. This disease affects approximately 30 % of the adult population and is the result of metabolic abnormalities rather than alcohol consumption. Additionally, MASLD is associated with an increased risk of cardiovascular disease (CVD), chronic liver disease, and a variety of cancers, particularly gastrointestinal cancers. Clonal hematopoiesis (CH) is a biological state characterized by the expansion of a population of blood cells derived from a single mutated hematopoietic stem cell. The presence of CH in the absence of a diagnosed blood disorder or cytopenia is known as clonal hematopoiesis of indeterminate potential (CHIP), which itself increases the risk of hematological malignancies and CVD. Steatotic liver disease may also complicate the clinical course of cancer patients receiving antineoplastic agents, a condition referred to as chemotherapy induced steatohepatitis (CASH). This review will present an outline of the various aspects of MASLD, including complications. Furthermore, it will summarize the existing knowledge on the emerging association between CHIP and MASLD and present the available data on patient cases with concurrent MASLD and hematological neoplasms. Finally, it will provide a brief overview of the chemotherapeutic drugs associated with CASH, the underlying pathophysiologic mechanisms and their clinical implications.

Clinical care guidance in patients with diabetes and metabolic dysfunction-associated steatotic liver disease: A joint consensus

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent chronic liver disease worldwide, affecting >30% of the global population. Metabolic dysregulation, particularly insulin resistance and its subsequent manifestation as type 2 diabetes mellitus, serves as the fundamental pathogenesis of metabolic liver disease. Clinical evidence of the recent nomenclature evolution is accumulating. The interaction and impacts are bidirectional between MASLD and diabetes in terms of disease course, risk, and prognosis. Therefore, there is an urgent need to highlight the multifaceted links between MASLD and diabetes for both hepatologists and diabetologists. The surveillance strategy, risk stratification of management, and current therapeutic achievements of metabolic liver disease remain the major pillars in a clinical care setting. Therefore, the Taiwan Association for the Study of the Liver (TASL), Taiwanese Association of Diabetes Educators, and Diabetes Association of the Republic of China (Taiwan) collaboratively completed the first guidance in patients with diabetes and MASLD, which provides practical recommendations for patient care.

Gut microbes, diet, and genetics as drivers of metabolic liver disease: a narrative review outlining implications for precision medicine

Metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing in prevalence, impacting over a third of the global population. The advanced form of MASLD, Metabolic dysfunction-associated steatohepatitis (MASH), is on track to become the number one indication for liver transplant. FDA-approved pharmacological agents are limited for MASH, despite over 400 ongoing clinical trials, with only a single drug (resmetirom) currently on the market. This is likely due to the heterogeneous nature of disease pathophysiology, which involves interactions between highly individualized genetic and environmental factors. To apply precision medicine approaches that overcome interpersonal variability, in-depth insights into interactions between genetics, nutrition, and the gut microbiome are needed, given that each have emerged as dynamic contributors to MASLD and MASH pathogenesis. Here, we discuss the associations and molecular underpinnings of several of these factors individually and outline their interactions in the context of both patient-based studies and preclinical animal model systems. Finally, we highlight gaps in knowledge that will require further investigation to aid in successfully implementing precision medicine to prevent and alleviate MASLD and MASH.

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.

Deciphering the multifaceted role of microRNAs in hepatocellular carcinoma: Integrating literature review and bioinformatics analysis for therapeutic insights

Hepatocellular carcinoma (HCC) poses a significant global health challenge, necessitating innovative therapeutic strategies. MicroRNAs (miRNAs) have emerged as pivotal regulators of HCC pathogenesis, influencing key processes such as self-renewal, angiogenesis, glycolysis, autophagy, and metastasis. This article integrates findings from a comprehensive literature review and bioinformatics analysis to elucidate the role of miRNAs in HCC. We discuss how dysregulation of miRNAs can drive HCC initiation, progression, and metastasis by modulating various signaling pathways and target genes. Moreover, leveraging high-throughput technology and bioinformatics tools, we identify key miRNAs involved in multiple cancer hallmarks, offering insights into potential combinatorial therapeutic strategies. Through our analysis considering p-values and signaling pathways associated with key features, we unveil miRNAs with simultaneous roles across critical cancer characteristics, providing a basis for the development of high-performance biomarkers. The microRNAs, miR-34a-5p, miR-373-3p, miR-21-5p, miR-214-5p, miR-195-5p, miR-139-5p were identified to be shared microRNAs in stemness, angiogenesis, glycolysis, autophagy, EMT, and metastasis of HCC. However, challenges such as miRNA stability and delivery hinder the translation of miRNA-based therapeutics into clinical practice. This review underscores the importance of further research to overcome existing barriers and realize the full potential of miRNA-based interventions for HCC management.

Decoding 17-Beta-hydroxysteroid Dehydrogenase 13: A Multifaceted Perspective on Its Role in Hepatic Steatosis and Associated Disorders

Chronic liver disease (CLD) represents a significant global health burden, with hepatic steatosis-associated disorders-such as metabolic dysfunction-associated steatohepatitis (MASH), alcoholic liver disease, and hepatitis C virus infection-being major contributors. Recent genome-wide association studies have identified the rs72613567:TA variant in the 17-beta-hydroxysteroid dehydrogenase 13 (HSD17B13) gene as a protective factor against the development and progression of these conditions. In this review, we summarized the current evidence surrounding the HSD17B13 rs72613567 variant, aiming to elucidate its impact on CLD risk and outcomes, and to explore the potential mechanisms behind its hepatoprotective effects. The rs72613567:TA variant induces a splice donor site mutation, resulting in a truncated, non-functional HSD17B13 protein. Numerous studies have demonstrated that this loss-of-function mutation confers protection against the development of cirrhosis and hepatocellular carcinoma (HCC) in patients with MASH, alcoholic liver disease, and hepatitis C virus infection. Moreover, the rs72613567:TA variant has been associated with reduced liver enzyme levels and improved survival in HCC patients. Integrating this variant into genetic risk scores has shown promise in predicting the progression of fatty liver disease to cirrhosis and HCC. Furthermore, inhibiting HSD17B13 expression through RNA interference and small molecule inhibitors has emerged as a potential therapeutic strategy for MASH. However, the precise molecular mechanisms underlying the hepatoprotective effects of the HSD17B13 rs72613567 variant remain to be fully elucidated. Future research should focus on clarifying the structure-function relationship of HSD17B13 and its role in liver pathophysiology to facilitate the development of targeted therapies for CLD associated with hepatic steatosis.