Critical appraisal of metabolic dysfunction-associated steatotic liver disease: Implication of Janus-faced modernity

Metabolic Dysfunction-Associated Steatotic Liver Disease and Metabolic Dysfunction-Associated Steatotic Liver Disease with Increased Alcohol Intake Increase the Risk of Developing Hepatocellular Carcinoma and Incident or Decompensated Cirrhosis: A Korean Nationwide Study

Introduction

This study aimed to investigate the liver-related outcomes of newly suggested metabolic dysfunction-associated steatotic liver disease (MASLD) and MASLD with increased alcohol intake (MetALD), as well as alcohol-associated liver disease (ALD).

Methods

From a National Health Insurance Service Health Screening Cohort, we included 369,094 participants who underwent health checkups between 2009 and 2010 in South Korea. Steatotic liver disease (SLD) was defined as a fatty liver index ≥60. The risk of primary liver cancer (PLCa), hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), incident cirrhosis, and decompensated cirrhosis was compared with no SLD. The subdistribution hazard ratio (SHR) was calculated using the Fine-Gray model regarding competing risks.

Results

A total of 3,232 participants (0.9%) developed PLCa during the median follow-up of 3,227,176 person-years: 0.5% with no SLD, 1.1% with MASLD, 1.3% with MetALD, and 1.9% with ALD. Competing risk analysis revealed that compared with no SLD, MASLD (SHR: 1.65; 95% CI: 1.44-1.88), MetALD (SHR: 1.87; 95% CI: 1.52-2.29), and ALD (SHR: 1.86; 95% CI: 1.39-2.49) were associated with an increased risk of PLCa. MASLD (SHR: 1.96; 95% CI: 1.67-2.31), MetALD (SHR: 2.23; 95% CI: 1.75-2.84), and ALD (SHR: 2.34; 95% CI: 1.67-3.29) were associated with a higher risk of HCC. No significant difference was observed in the risk of iCCA. The risk of incident cirrhosis and decompensated cirrhosis increased in the order of no SLD, MASLD, MetALD, and ALD.

Conclusion

MASLD, MetALD, and ALD have an increased risk of PLCa, HCC, incident cirrhosis, and decompensated cirrhosis but not iCCA. These findings may serve as a robust ground for the prognostic value of the newly suggested MASLD and MetALD.

Role of Neutrophils in the Development of Steatotic Liver Disease

This review explores the biological aspects of neutrophils, their contributions to the development of steatotic liver disease, and their potential as therapeutic targets for the disease. Although alcohol-associated and metabolic dysfunction-associated liver diseases originate from distinct etiological factors, the two diseases frequently share excessive lipid accumulation as a common contributor to their pathogenesis, thereby classifying them as types of steatotic liver disease. Dysregulated lipid deposition in the liver induces hepatic injury, triggering the activation of the innate immunity, partially through neutrophil recruitment. Traditionally recognized for their role in microbial clearance, neutrophils have recently garnered attention for their involvement in sterile inflammation, a pivotal component of steatotic liver disease pathogenesis. In conclusion, technological innovations, including single-cell RNA sequencing, have gradually disclosed the existence of various neutrophil subsets; however, how the distinct subsets of neutrophil population contribute differentially to the development of steatotic liver disease remains unclear.

Emerging mechanisms of non-alcoholic steatohepatitis and novel drug therapies

Non-alcoholic fatty liver disease (NAFLD) has become a leading cause of chronic liver disease globally. It initiates with simple steatosis (NAFL) and can progress to the more severe condition of non-alcoholic steatohepatitis (NASH). NASH often advances to end-stage liver diseases such as liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Notably, the transition from NASH to end-stage liver diseases is irreversible, and the precise mechanisms driving this progression are not yet fully understood. Consequently, there is a critical need for the development of effective therapies to arrest or reverse this progression. This review provides a comprehensive overview of the pathogenesis of NASH, examines the current therapeutic targets and pharmacological treatments, and offers insights for future drug discovery and development strategies for NASH therapy.

Interleukin-mediated therapies in liver diseases and comorbidity effects

Cytokines like interleukins (ILs) play important roles in inflammation and innate immune. Yang and Zhang carried out an interesting study related to ILs and hepatic diseases. They described the role of ILs in the pathogenesis and resolution of hepatic disorders. The authors summarized alcohol-related liver disease and virus-induced hepatitis, as far as clinical studies a fortiori carried out on IL-mediated treatments pertaining to these dysfunctions. This editorial contributes to the review by Yang and Zhang titled, "Interleukins in liver disease treatment", and focuses on therapies mediated by ILs in comorbid liver diseases. The documentary search was conducted on recent pertinent literature, primarily using the Google Scholar and PubMed databases.

Are transmembrane 6 superfamily member 2 gene polymorphisms associated with steatohepatitis after pancreaticoduodenectomy?

Aim

After pancreaticoduodenectomy, 20-40% of patients develop steatotic liver disease (SLD), and steatohepatitis can be a problem. Although patatin-like phospholipase domain-containing 3 protein (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2) polymorphisms are involved in SLD and steatohepatitis development, whether this is the case after pancreaticoduodenectomy is unclear.

Methods and Results

Forty-three patients with pancreatic cancer who underwent pancreaticoduodenectomy at our hospital between April 1, 2018, and March 31, 2021, were included. We extracted DNA from noncancerous areas of residual specimens after pancreaticoduodenectomy and determined PNPLA3 and TM6SF2 gene polymorphisms using real-time polymerase chain reaction. SLD was defined as a liver with an attenuation value of ≤40 HU or a liver-to-spleen ratio of ≤0.9 on computed tomography. We defined high hepatic fibrosis indexes (HFI) instead of steatohepatitis as a Fibrosis-4 index of ≥2.67 or nonalcoholic fatty liver disease fibrosis score of ≥0.675 in patients with SLD. The cumulative incidence of SLD (P = 0.299) and high HFI (P = 0.987) after pancreaticoduodenectomy were not significantly different between the PNPLA3 homozygous and minor allele groups. The incidences of high HFI at 1 year after pancreaticoduodenectomy were 16.8% and 27.0% in the TM6SF2 major homozygous and minor allele groups, respectively, with a significant difference in the cumulative incidence (P = 0.046).

Conclusion

The TM6SF2 minor allele may contribute to steatohepatitis development after pancreaticoduodenectomy.

Prognostic Impact of Metabolic Syndrome and Steatotic Liver Disease in Hepatocellular Carcinoma Using Machine Learning Techniques

Metabolic dysfunction-associated steatotic liver disease (MASLD) currently represents the predominant cause of chronic liver disease and is closely linked to a significant increase in the risk of hepatocellular carcinoma (HCC), even in the absence of liver cirrhosis. In this retrospective multicenter study, machine learning (ML) methods were employed to investigate the relationship between metabolic profile and prognosis at diagnosis in a total of 219 HCC patients. The eXtreme Gradient Boosting (XGB) method demonstrated superiority in identifying mortality predictors in our patients. Etiology was the most determining prognostic factor followed by Barcelona Clinic Liver Cancer (BCLC) and Eastern Cooperative Oncology Group (ECOG) classifications. Variables related to the development of hepatic steatosis and metabolic syndrome, such as elevated levels of alkaline phosphatase (ALP), uric acid, obesity, alcohol consumption, and high blood pressure (HBP), had a significant impact on mortality prediction. This study underscores the importance of metabolic syndrome as a determining factor in the progression of HCC secondary to MASLD. The use of ML techniques provides an effective tool to improve risk stratification and individualized therapeutic management in these patients.

Steatotic Liver Disease: Pathophysiology and Emerging Pharmacotherapies

Steatotic liver disease (SLD) displays a dynamic and complex disease phenotype. Consequently, the metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) therapeutic pipeline is expanding rapidly and in multiple directions. In parallel, noninvasive tools for diagnosing and monitoring responses to therapeutic interventions are being studied, and clinically feasible findings are being explored as primary outcomes in interventional trials. The realization that distinct subgroups exist under the umbrella of SLD should guide more precise and personalized treatment recommendations and facilitate advancements in pharmacotherapeutics. This review summarizes recent updates of pathophysiology-based nomenclature and outlines both effective pharmacotherapeutics and those in the pipeline for MASLD/MASH, detailing their mode of action and the current status of phase 2 and 3 clinical trials. Of the extensive arsenal of pharmacotherapeutics in the MASLD/MASH pipeline, several have been rejected, whereas other, mainly monotherapy options, have shown only marginal benefits and are now being tested as part of combination therapies, yet others are still in development as monotherapies. Although the Food and Drug Administration (FDA) has recently approved resmetirom, additional therapeutic approaches in development will ideally target MASH and fibrosis while improving cardiometabolic risk factors. Due to the urgent need for the development of novel therapeutic strategies and the potential availability of safety and tolerability data, repurposing existing and approved drugs is an appealing option. Finally, it is essential to highlight that SLD and, by extension, MASLD should be recognized and approached as a systemic disease affecting multiple organs, with the vigorous implementation of interdisciplinary and coordinated action plans. SIGNIFICANCE STATEMENT: Steatotic liver disease (SLD), including metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, is the most prevalent chronic liver condition, affecting more than one-fourth of the global population. This review aims to provide the most recent information regarding SLD pathophysiology, diagnosis, and management according to the latest advancements in the guidelines and clinical trials. Collectively, it is hoped that the information provided furthers the understanding of the current state of SLD with direct clinical implications and stimulates research initiatives.

The clinician's view on the advantages and contradictions of the new nomenclature of steatotic liver disease: A review

In September 2023, the European Association for the Study of the Liver (EASL) updated the disease nomenclature for non-alcoholic (metabolically associated) fatty liver disease. The goals of the revision were to increase awareness among health care professionals, civil society and patients about the disease, its course, treatment and outcomes; combating stigma; focusing on the initial etiological factor, including the main (cardiometabolic) risk of disease progression; improved diagnosis based on disease biomarkers; positive impact on the potency to search for new drugs; the ability to provide personalized medical care. The terms “non-alcoholic” and “fatty” were considered stigmatizing, and therefore, it was proposed to use the term steatotic liver disease (SLD) as the name of this nosology. The terms non-alcoholic fatty liver disease (NAFLD) or metabolic associated fatty liver disease (MAFLD) have been replaced by the term metabolic dysfunction-associated steatotic liver disease (MASLD). In the case of being combined with an alcohol factor, a diagnosis in which metabolic dysfunction is combined with alcoholic liver disease is referred to as MetALD. The fundamental principle in the diagnosis of MASLD is the presence of at least one of the cardiometabolic risk factors. Alcohol consumption interacts with cardiometabolic risk factors and increases the risk of SLD decompensation. The term nonalcoholic steatohepatitis (NASH), according to the new nomenclature, has been replaced by the term metabolic dysfunction-associated steatohepatitis (MASH). The adoption of the new nomenclature should help to increase awareness about the disease, its course and outcomes, as well as improve the quality of diagnosis and treatment.

Clinical profiles and mortality rates are similar for metabolic dysfunction-associated steatotic liver disease and non-alcoholic fatty liver disease

BACKGROUND & AIMS

Recently, the term metabolic dysfunction-associated steatotic liver disease (MASLD) has replaced non-alcoholic fatty liver disease (NAFLD). Concern remains regarding whether the evidence generated under the NAFLD definition can be used for MASLD. We compared the clinical profile and outcomes of NAFLD to MASLD using tertiary care- and population-based data.

METHODS

Comparison data were obtained from our NAFLD database and the National Health and Nutrition Examination Survey (NHANES III). Clinical profiles and non-invasive tests (enhanced liver fibrosis [ELF] score, fibrosis-4 index [FIB-4] and vibration-controlled transient elastography) were compared. Mortality data were obtained from NHANES-National Death Index. All-cause mortality was assessed by Cox proportional hazards regression models and cause-specific mortality by competing risk analysis.

RESULTS

There were 6,429 patients in the NAFLD database (age: 54 ± 12 years, 42% male, BMI 35.4 ± 8.3, waist circumference 112 ± 17 cm, 52% type 2 diabetes). Average scores for ELF, FIB-4 and liver stiffness were 9.6 ± 1.2, 1.69 ± 1.24,14.0 ± 11.8 kPa, respectively; 99% met MASLD criteria; 95% met MASLD on BMI only. Predictive accuracy of ELF and FIB-4 were identical between MASLD and NAFLD. We included 12,519 eligible participants from NHANES (age 43.00 years, 47.38% male, 22.70% obese, 7.28% type 2 diabetes, 82.51% ≥1 cardiometabolic criteria). Among the NHANES study population, there was excellent concordance between MASLD and NAFLD diagnoses: Cohen's kappa coefficient: 0.968 (95% CI 0.962-0.973) with 5.29% of NAFLD cases not meeting MASLD criteria. After a median follow-up of 22.83 years, there were no mortality differences between MASLD and NAFLD diagnoses (p values ≥0.05).

CONCLUSIONS

NAFLD and MASLD are similar except individuals with MASLD seem to be older with slightly higher mortality risk, likely owing to cardiometabolic risk factors. Clinical profiles and non-invasive test thresholds were also identical. These data provide evidence that NAFLD and MASLD terminologies can be used interchangeably. For the small proportion of patients with NAFLD who do not meet MASLD criteria, further consideration is needed.

IMPACT AND IMPLICATIONS

In June 2023, new terminology (MASLD) was adopted to replace the term NAFLD as a means to better describe what the liver disease is rather than what it is not, as well as to potentially reduce stigma. Given that MASLD requires at least one cardiometabolic risk factor, questions were raised as to whether this change in the definition would nullify the similarities between NAFLD and MASLD and require new evidence to be generated for MASLD. We used our NAFLD database and a US population-based database to show that the vast majority of patients with NAFLD fulfill criteria for MASLD. Non-invasive tests performed similarly in both groups. Mortality risk was slightly higher in those with MASLD, which is attributed to the presence of cardiometabolic risks. These results provide evidence that data generated in the past three decades for NAFLD can be used interchangeably for MASLD.

Metabolic dysfunction-associated steatotic liver disease: An opportunity for collaboration between cardiology and hepatology

Altered metabolic function has many detrimental effects on the body that can manifest as cardiovascular and liver diseases. Traditional approaches to understanding and treating metabolic dysfunction-associated disorders have been organ-centered, leading to silo-type disease care. However, given the broad impact that systemic metabolic dysfunction has on the human body, approaches that simultaneously involve multiple medical specialists need to be developed and encouraged to optimize patient outcomes. In this review, we highlight how several of the treatments developed for cardiac care may have a beneficial effect on the liver and vice versa, suggesting that there is a need to target the disease process, rather than specifically target the cardiovascular or liver specific sequelae of metabolic dysfunction.

Prognosis of biopsy-confirmed metabolic dysfunction- associated steatotic liver disease: A sub-analysis of the CLIONE study

BACKGROUND/AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) was recently proposed as an alternative disease concept to nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the prognosis of patients with biopsy-confirmed MASLD using data from a multicenter study.

METHODS

This was a sub-analysis of the Clinical Outcome Nonalcoholic Fatty Liver Disease (CLIONE) study that included 1,398 patients with NAFLD. Liver biopsy specimens were pathologically diagnosed and histologically scored using the NASH Clinical Research Network system, the FLIP algorithm, and the SAF score. Patients who met at least one cardiometabolic criterion were diagnosed with MASLD.

RESULTS

Approximately 99% of cases (n=1,381) were classified as MASLD. Patients with no cardiometabolic risk (n=17) had a significantly lower BMI than patients with MASLD (20.9 kg/m2 vs. 28.0 kg/m2, P<0.001), in addition to significantly lower levels of inflammation, ballooning, NAFLD activity score, and fibrosis stage based on liver histology. These 17 patients had a median follow-up of 5.9 years, equivalent to 115 person-years, with no deaths, liver-related events, cardiovascular events, or extrahepatic cancers. The results showed that the prognosis for pure MASLD was similar to that for the original CLIONE cohort, with 47 deaths and one patient who underwent orthotopic liver transplantation. The leading cause of death was extrahepatic cancer (n=10), while the leading causes of liver-related death were liver failure (n=9), hepatocellular carcinoma (n=8), and cholangiocarcinoma (n=4).

CONCLUSION

Approximately 99% of NAFLD cases were considered MASLD based on the 2023 liver disease nomenclature. The NAFLD-only group, which is not encompassed by MASLD, had a relatively mild histopathologic severity and a favorable prognosis. Consequently, the prognosis of MASLD is similar to that previously reported for NAFLD.

Identification of signature gene set as highly accurate determination of metabolic dysfunction-associated steatotic liver disease progression

BACKGROUND/AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by fat accumulation in the liver. MASLD encompasses both steatosis and MASH. Since MASH can lead to cirrhosis and liver cancer, steatosis and MASH must be distinguished during patient treatment. Here, we investigate the genomes, epigenomes, and transcriptomes of MASLD patients to identify signature gene set for more accurate tracking of MASLD progression.

METHODS

Biopsy-tissue and blood samples from patients with 134 MASLD, comprising 60 steatosis and 74 MASH patients were performed omics analysis. SVM learning algorithm were used to calculate most predictive features. Linear regression was applied to find signature gene set that distinguish the stage of MASLD and to validate their application into independent cohort of MASLD.

RESULTS

After performing WGS, WES, WGBS, and total RNA-seq on 134 biopsy samples from confirmed MASLD patients, we provided 1,955 MASLD-associated features, out of 3,176 somatic variant callings, 58 DMRs, and 1,393 DEGs that track MASLD progression. Then, we used a SVM learning algorithm to analyze the data and select the most predictive features. Using linear regression, we identified a signature gene set capable of differentiating the various stages of MASLD and verified it in different independent cohorts of MASLD and a liver cancer cohort.

CONCLUSION

We identified a signature gene set (i.e., CAPG, HYAL3, WIPI1, TREM2, SPP1, and RNASE6) with strong potential as a panel of diagnostic genes of MASLD-associated disease.

Steatotic liver disease predicts cardiovascular disease and advanced liver fibrosis: A community-dwelling cohort study with 20-year follow-up

BACKGROUND

Steatotic liver disease (SLD) has emerged as new nomenclature to increase awareness and reflect the pathophysiology of the disease better. We investigated the risk of advanced fibrosis and cardiovascular disease (CVD) in SLD using data derived from a Korean prospective cohort.

METHODS

We defined SLD using the fatty liver index (FLI) and identified advanced fibrosis with the age-adjusted Fibrosis-4 Index. SLD was further subcategorized into metabolic dysfunction-associated SLD (MASLD), MASLD with increased alcohol intake (MetALD), and alcohol-associated liver disease (ALD).

FINDINGS

The Ansung-Ansan cohort of the Korean Genome and Epidemiology study, following 9497 participants from 2002 to 2020, included 3642 (38.3%) with MASLD, 424 (4.5%) with MetALD, and 207 (2.1%) with ALD. During the median follow-up of 17.5 years, CVD risk was higher in those with MASLD (hazard ratio [HR], 1.27; 95% confidence interval [CI], 1.12-1.45; P < 0.001), MetALD (HR, 1.88; 95% CI, 1.33-2.65; P < 0.001), and ALD (HR, 1.95; 95% CI, 1.01-3.77; P < 0.001) than in those without SLD, after adjusting for conventional risk factors. Notably, CVD risk was higher in the MetALD than in the MASLD group (P = 0.027). In the MASLD group, the number of cardiometabolic risk factors (CMRFs) correlated positively with CVD risk (HR, 1.34; 95% CI, 1.24-1.45; P < 0.001 for trend). Among the CMRFs, hypertension (HR, 1.94; 95% CI, 1.63-2.31; P < 0.001) was the predominant contributor to CVD. The MASLD (HR, 1.39; 95% CI, 1.25-1.55; P < 0.001), MetALD (HR, 1.75; 95% CI, 1.38-2.23; P < 0.001), and ALD (HR, 2.00; 95% CI, 1.30-3.07; P = 0.002) groups had a higher risk of advanced fibrosis than did the non-SLD group (P < 0.001 for trend).

INTERPRETATION

Our study provides new insight into hepatic and cardiovascular outcomes related to SLD subtypes. The risk of CVD increased in the order of no SLD, MASLD, and MetALD. The SLD subcategories, considering CMRFs and alcohol intake, outperformed traditional fatty liver categorizations in predicting CVD risk. The proposed SLD terminology could impact clinical practice, warranting further exploration of the heterogeneity of clinical outcomes among SLD subtypes.

From Nonalcoholic Fatty Liver Disease to Metabolic Dysfunction-Associated Steatotic Liver Disease: Out with the Old, in with the New

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease (CLD) affecting a quarter of the global population [...].

Gut microbiota-derived indole compounds attenuate metabolic dysfunction-associated steatotic liver disease by improving fat metabolism and inflammation

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease, and its prevalence has increased worldwide in recent years. Additionally, there is a close relationship between MASLD and gut microbiota-derived metabolites. However, the mechanisms of MASLD and its metabolites are still unclear. We demonstrated decreased indole-3-propionic acid (IPA) and indole-3-acetic acid (IAA) in the feces of patients with hepatic steatosis compared to healthy controls. Here, IPA and IAA administration ameliorated hepatic steatosis and inflammation in an animal model of WD-induced MASLD by suppressing the NF-κB signaling pathway through a reduction in endotoxin levels and inactivation of macrophages. Bifidobacterium bifidum metabolizes tryptophan to produce IAA, and B. bifidum effectively prevents hepatic steatosis and inflammation through the production of IAA. Our study demonstrates that IPA and IAA derived from the gut microbiota have novel preventive or therapeutic potential for MASLD treatment.

Metabolic dysfunction-associated steatotic liver disease increases the risk of incident cardiovascular disease: a nationwide cohort study

Background

The various subcategories under the overarching term of steatotic liver disease (SLD) have been recently proposed by the nomenclature consensus group and endorsed by international academic liver societies. Our aim was to investigate the association between each subtype of SLD and incident cardiovascular disease (CVD) in a nationwide Korean cohort.

Methods

From a nationwide health screening database from Korea, 351,068 individuals aged 47-86 years between January 1, 2009 and December 31, 2010 were included and followed until December 31, 2019 for a median of 9.0 years. Individuals were categorised into no SLD, metabolic dysfunction-associated steatotic liver disease (MASLD), MASLD with increased alcohol intake (MetALD), and alcohol-related liver disease (ALD). Hepatic steatosis was defined as fatty liver index ≥60. The primary outcome was a composite CVD, which includes non-fatal and fatal myocardial infarction and stroke. The subdistribution hazard ratio (SHR) was calculated using the Fine-Gray model with treating non-CVD-related death as a competing risk.

Findings

There were 199,817 male (56.9%) and 151,251 female (43.1%) with a median age of 55 years (interquartile range, 50-61). The prevalence of no SLD, MASLD, MetALD, and ALD was 44.3%, 47.2%, 6.4%, and 2.1%, respectively; and the incidence rate of CVD in each subcategory was 6.2, 8.5, 8.5, and 9.6 per 1000 person-years, respectively. MASLD (SHR, 1.19; 95% confidence interval [CI], 1.15-1.24), MetALD (SHR, 1.28; 95% CI, 1.20-1.36), and ALD (SHR, 1.29; 95% CI, 1.18-1.41) increased the risk of CVD compared to no SLD, which increment was in consecutive order (Ptrend < 0.001).

Interpretation

Individuals with MASLD, MetALD, or ALD are at an increased risk of developing incident CVD. Higher risk of CVD observed in MetALD compared to MASLD suggests the additive impact of alcohol consumption in conjunction with cardiometabolic risk factors on CVD development. These findings support and validate the utility of the new consensus criteria for SLD in predicting CVD.

Funding

The National Research Foundation of Korea and the Korea Centers for Disease Control and Prevention.