FXR agonists for MASH therapy: Lessons and perspectives from obeticholic acid.

Nonalcoholic fatty liver disease, also called metabolic dysfunction-associated steatotic liver disease, is the most common liver disease worldwide and has no approved pharmacotherapy. Due to its beneficial effects on metabolic regulation, inflammation suppression, cell death prevention, and fibrogenesis inhibition, farnesoid X receptor (FXR) is widely accepted as a promising therapeutic target for nonalcoholic steatosis (NASH) or called metabolic dysfunction-associated steatohepatitis (MASH). Many FXR agonists have been developed for NASH/MASH therapy. Obeticholic acid (OCA) is the pioneering frontrunner FXR agonist and the first demonstrating success in clinical trials. Unfortunately, OCA did not receive regulatory approval as a NASH pharmacotherapy because its moderate benefits did not outweigh its safety risks, which may cast a shadow over FXR-based drug development for NASH/MASH. This review summarizes the milestones in the development of OCA for NASH/MASH and discuss its limitations, including moderate hepatoprotection and the undesirable side effects of dyslipidemia, pruritus, cholelithiasis, and liver toxicity risk, in depth. More importantly, we provide perspectives on FXR-based therapy for NASH/MASH, hoping to support a successful bench-to-clinic transition.

Outcomes of radiofrequency ablation for hepatocellular carcinoma with concurrent steatotic liver disease.

BACKGROUND: Steatotic liver disease (SLD) is an emerging liver disease that has been associated with an increased risk for hepatocellular carcinoma (HCC). The impact of concurrent SLD on the prognosis of HCC remains unknown. This study investigates how concurrent SLD affects the outcomes of patients with HCC undergoing curative radiofrequency ablation (RFA) therapy. METHODS: A retrospective analysis of patients with early-stage HCC receiving curative RFA at a tertiary medical center was conducted. Laboratory data and HCC characteristics were recorded and analyzed by a Cox proportional hazards regression model to predict recurrence and all-cause mortality after RFA. RESULTS: A total of 598 patients with HCC were included between 2005 and 2015, with 139 and 459 classified in SLD and non-SLD groups, respectively. The SLD group exhibited a significantly better liver reserve and a lower cumulative incidence of HCC recurrence and liver-related and all-cause mortality after a median follow-up of 51 months. After adjusting for metabolic dysfunction, liver reserve, and HCC characteristics, the presence of SLD reduced all-cause mortality (adjusted hazard ratio [aHR], 0.67; 95% confidence interval [CI], 0.45-0.996; p = .048), which was supported by inverse probability weighting analysis (aHR, 0.65; 95% CI, 0.42-1.00; p = .049). Poor liver functional reserve (high albumin-bilirubin grades) increased all-cause mortality dose dependently. Barcelona Clinic Liver Cancer staging and a higher Fibrosis-4 index were predictors for HCC recurrence, whereas SLD was not. CONCLUSIONS: Among patients with HCC undergoing curative RFA, those with concurrent SLD had a lower risk of all-cause mortality compared to those with poor liver functional reserve. PLAIN LANGUAGE SUMMARY: The present research demonstrated that patients with both liver cancer and steatotic liver disease who received curative radiofrequency ablation for liver cancer survived longer compared to those without steatotic liver disease. Maintaining good liver function is an important prognostic factor for survival.

Targeting PYK2 with heterobifunctional T6BP helps mitigate MASLD and MASH-HCC progression.

BACKGROUND & AIMS: The mechanisms underlying the regulation of hepatocyte non-receptor tyrosine kinases in metabolic dysfunction-associated steatohepatitis (MASH) remain largely unclear. METHODS: Hepatocyte-specific overexpression or deletion and anti-protein tyrosine kinase 2 beta (PYK2) or anti-TRAF6-binding protein (T6BP) crosslinking were utilised to study fatty liver protection by T6BP. P-PTC, a peptide-proteolysis targeting chimaera, degrades PYK2 to block MASH progression. RESULTS: Since PYK2 activation is promoter signalling in steatohepatitis development, we find that T6BP is a novel and critical suppressor of PYK2 that reduces hepatic lipid accumulation, pro-inflammatory factor release, and pro-fibrosis production by ubiquitin ligase CBL to degrade PYK2. Mechanistic evidence suggests that T6BP directly targets PYK2 and prevents its N-terminal FERM domain-triggered dimerization, disrupting downstream PYK2-JNK signalling hyperactivation. Additionally, T6BP favourably recruits CBL, a particular E3 ubiquitin ligase targeting PYK2, to form a complex and degrade PYK2. T6BP (F1), a core fragment of T6BP, directly blocks N-terminal FERM domain-associated dimerization of PYK2, followed by T6BP-recruiting CBL-mediated PYK2 degradation in a typical T6BP-dependent manner when the tiny fragment is specifically expressed using thyroxine binding globulin (TBG)-ground vectors. This inhibits the progression of MASH, metabolic dysfunction-associated steatotic liver disease (MASLD)-related HCC (MASH-HCC), and metabolic syndrome in dietary rodent models. First-ever peptide-proteolysis targeting chimaera (P-PTC) based on the core segment of T6BP as a ligand for targeted recruitment of CBL targeting metabolic disorders like MASH has been devised and validated in animal models. CONCLUSIONS: Our study revealed a previously unknown mechanism: identification of T6BP as a key eliminator of fatty liver strongly contributes to the development of promising therapeutic targets, and the discovery of crucial fragments of T6BP-based pharmacon that interrupt PYK2 dimerization are novel and viable treatments for fatty liver and its advanced symptoms and complications. IMPACT AND IMPLICATIONS: Excessive high-energy diet ingestion is critical in driving steatohepatitis via regulation of hepatocyte non-receptor tyrosine kinases. The mechanisms under lying the regulation of hepatocyte PYK2 in metabolic dysfunction-associated steatohepatitis (MASH) remain largely unclear. Here, we found that T6BP as a critical fatty liver eliminator has a significant impact on the development of promising therapeutic targets. Additionally, vital T6BP-based pharmacon fragments that impede PYK2 dimerization have been found, offering new and effective treatments for advanced fatty liver symptoms and complications.

Bidirectional modulation of TCA cycle metabolites and anaplerosis by metformin and its combination with SGLT2i.

BACKGROUND: Metformin and sodium-glucose-cotransporter-2 inhibitors (SGLT2i) are cornerstone therapies for managing hyperglycemia in diabetes. However, their detailed impacts on metabolic processes, particularly within the citric acid (TCA) cycle and its anaplerotic pathways, remain unclear. This study investigates the tissue-specific metabolic effects of metformin, both as a monotherapy and in combination with SGLT2i, on the TCA cycle and associated anaplerotic reactions in both mice and humans. METHODS: Metformin-specific metabolic changes were initially identified by comparing metformin-treated diabetic mice (MET) with vehicle-treated db/db mice (VG). These findings were then assessed in two human cohorts (KORA and QBB) and a longitudinal KORA study of metformin-naïve patients with Type 2 Diabetes (T2D). We also compared MET with db/db mice on combination therapy (SGLT2i + MET). Metabolic profiling analyzed 716 metabolites from plasma, liver, and kidney tissues post-treatment, using linear regression and Bonferroni correction for statistical analysis, complemented by pathway analyses to explore the pathophysiological implications. RESULTS: Metformin monotherapy significantly upregulated TCA cycle intermediates such as malate, fumarate, and α-ketoglutarate (α-KG) in plasma, and anaplerotic substrates including hepatic glutamate and renal 2-hydroxyglutarate (2-HG) in diabetic mice. Downregulated hepatic taurine was also observed. The addition of SGLT2i, however, reversed these effects, such as downregulating circulating malate and α-KG, and hepatic glutamate and renal 2-HG, but upregulated hepatic taurine. In human T2D patients on metformin therapy, significant systemic alterations in metabolites were observed, including increased malate but decreased citrulline. The bidirectional modulation of TCA cycle intermediates in mice influenced key anaplerotic pathways linked to glutaminolysis, tumorigenesis, immune regulation, and antioxidative responses. CONCLUSION: This study elucidates the specific metabolic consequences of metformin and SGLT2i on the TCA cycle, reflecting potential impacts on the immune system. Metformin shows promise for its anti-inflammatory properties, while the addition of SGLT2i may provide liver protection in conditions like metabolic dysfunction-associated steatotic liver disease (MASLD). These observations underscore the importance of personalized treatment strategies.

Sex-specific effects of PNPLA3 I148M.

Metabolic dysfunction-associated steatotic liver disease (MASLD, previously termed NAFLD, nonalcoholic fatty liver disease) is a complex multifactorial disease showing generally higher prevalence and severity in men than in women. With respect to women, men are also more prone to develop metabolic dysfunction-associated steatohepatitis, fibrosis and liver-related complications. Several genetic, hormonal, environmental and lifestyle factors may contribute to sex differences in MASLD development, progression and outcomes. However, after menopause, the sex-specific prevalence of MASLD shows an opposite trend between men and women, pointing to the relevance of oestrogen signalling in the sexual dimorphism of MASLD. The patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene, that encodes a triacylglycerol lipase that plays a crucial role in lipid metabolism, has emerged as a key player in the pathogenesis of MASLD, with the I148M variant being strongly associated with increased liver fat content and disease severity. Recent advances indicate that carrying the PNPLA3 I148M variant can be a risk factor for MASLD especially for women. To elucidate the molecular mechanisms underlying the sex-specific role of PNPLA3 I148M in the development of MASLD, several in vitro, ex vivo and in vivo models have been developed.

Role of PNPLA3 in Hepatic Stellate Cells and Hepatic Cellular Crosstalk.

AIMS: Since its discovery, the patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409 C>G p.I148M) variant has been studied extensively to unravel its molecular function. Although several studies proved a causal relationship between the PNPLA3 I148M variant and MASLD development and particularly fibrosis, the pathological mechanisms promoting this phenotype have not yet been fully clarified. METHODS: We summarise the latest data regarding the PNPLA3 I148M variant in hepatic stellate cells (HSCs) activation and macrophage biology or the path to inflammation-induced fibrosis. RESULTS: Elegant but contradictory studies have ascribed PNPLA3 a hydrolase or an acyltransferase function. The PNPLA3 I148M results in hepatic lipid accumulation, which predisposes the hepatocyte to lipotoxicity and lipo-apoptosis, producing DAMPs, cytokines and chemokines leading to recruitment and activation of macrophages and HSCs, propagating fibrosis. Recent studies showed that the PNPLA3 I148M variant alters HSCs biology via attenuation of PPARγ, AP-1, LXRα and TGFß activity and signalling. CONCLUSIONS: The advent of refined techniques in isolating HSCs has made PNPLA3's direct role in HSCs for liver fibrosis development more apparent. However, many other mechanisms still need detailed investigations.

Metabolic dysfunction-associated steatotic liver disease is associated with worse time in ranges in type 1 diabetes.

AIM: To investigate the relationship between continuous glucose monitoring (CGM)-derived glucometrics and metabolic dysfunction-associated steatotic liver disease (MASLD) in type 1 diabetes (T1D). METHODS: A cross-sectional study collecting data on anthropometrics, glucometrics and MASLD in adults with T1D using a CGM device was conducted. MASLD was assessed by abdominal ultrasound and the presence of at least one cardiometabolic criterion. Backward multivariable logistic regression models were applied to define variables independently associated with MASLD. RESULTS: A total of 302 consecutive participants were included (median age 49 [34-61] years, male sex 58%, median diabetes duration 29 [17-38] years, mean time in range [TIR] 55% ± 16%). MASLD was present in 17% of cases, and 32% had metabolic syndrome (MetS). MetS was significantly more prevalent in the MASLD group (65% vs. 25%, P < .0001). TIR (P = .038) and time below range (TBR) (P = .032) were lower and time above range (TAR) was higher (P = .006), whereas HbA1c did not reach significance (P = .068). No differences were found for the glycaemia risk index. TIR (P = .028), TAR (P = .007), TBR (P = .036), waist circumference (P < .001) and systolic blood pressure (P = .029) were independently associated with MASLD, while sex, age, aspartate aminotransferase/alanine aminotransferase ratio, gamma-glutamyl transferase, high-density lipoprotein cholesterol and triglycerides were not. CONCLUSIONS: TIR, TAR, TBR, waist circumference and systolic blood pressure were independently associated with MASLD.

Longitudinal evaluation of pediatric and young adult metabolic dysfunction-associated steatotic liver disease defined by MR elastography.

OBJECTIVES: To inform clinical monitoring of children and young adults with metabolic dysfunction-associated steatotic liver disease (MASLD) by characterizing the real-world natural history of MASLD and identifying baseline predictors of liver disease progression. MATERIALS AND METHODS: This retrospective study included consecutive patients ages < 23 years with MASLD who underwent serial MR elastography (MRE) and/or MR fat fraction (FF) examinations between 09/2009 and 11/2022. Outcomes of MASLD were defined based on maximum ratio values. A relative change ≥ 19% in liver stiffness measures (LSM) and an absolute change ≥ 5% for liver FF were considered clinically meaningful. Random intercept models characterized the yearly rate of change in LSM (kilopascals per year) and FF (percentage per year). RESULTS: One hundred twenty-one patients (87 males, mean age at baseline: 12 ± 3 [SD] years) underwent 297 MRE examinations. The mean interval between the first and last MRE was 34 (± 24) months (range: 1-120 months). Among the 114 patients with serial LSM, 33% (38/114) showed progression, 46% (53/114) remained stable, and 21% (23/114) showed regression. Among the 88 patients with serial FF measures, 57% (50/88) showed progression, 2% (2/88) remained stable, and 41% (36/88) showed regression. LSM progression was associated with Hispanic ethnicity, baseline BMI-for-age percentile, baseline mean liver FF, and GGT changes over time. Predictors for liver FF progression included ALT, AST, GGT, and LDL. CONCLUSION: In a real-world sample of children and young adults with MASLD who underwent serial liver MRI, a minority of patients demonstrated improvements in liver stiffness or FF over time. KEY POINTS: Question In children, there is scarce data regarding the natural history of MASLD. Findings In this retrospective study, most children and young adults with MASLD had either unchanged or worsening liver stiffness (n = 91/114, 79%) and liver fat (n = 52/88, 59%). Clinical relevance Our findings emphasize the need for optimized care in pediatric MASLD. The identified risk factors for the progression of liver fat and stiffness may help to identify children who require interventions beyond changes in lifestyle.

Evaluating the efficacy of 8 non-invasive models in predicting MASLD and progression: a prospective study.

BACKGROUND: Selecting the optimal non-invasive diagnostic model for MASLD (Metabolic Dysfunction-Associated Steatosis Liver Disease) and steatosis progression is a critical issue given the variety of available models. We aimed to compare the performance of eight clinical prediction models for diagnosing and predicting the progression of hepatic steatosis using MRI-PDFF (Magnetic Resonance Imaging-Derived Proton Density Fat Fraction), and validate the findings with FibroScan and histopathological results. METHODS: In this study, 846 participants were initially enrolled, with 108 undergoing liver biopsy and 706 completing one-year follow-up, including 26 who underwent repeat biopsy. We calculated scores for eight clinical prediction models (FAST, KNAFLD, HSI, FLI, Liver Fat Score, Liver Fat Equation, BAAT, LAP) using collected clinical data and defined steatosis progression as a 30% relative increase in liver fat content (LFC) measured by MRI-PDFF. CAP(Controlled Attenuation Parameter) and LSM (Liver Stiffness Measurement) were obtained by Fibroscan. MRI-PDFF served as the reference standard for evaluating model accuracy, and sensitivity analyses were performed using liver biopsy and Fibroscan results. RESULTS: Among the eight clinical models, NAS (nonalcoholic fatty liver disease activity score) showed higher correlation with the FAST and KNAFLD models (r: 0.62 and 0.52, respectively). Among the whole cohort (N = 846), KNAFLD was the best model for predicting different degrees of hepatic steatosis (AUC = 0.84). When the KNAFLD score was above 2.935, LFC was significantly higher (4.4% vs. 19.7%, P < 0.001). After 1 year of follow-up (N = 706), FAST performed best in predicting MASLD progression (AUC = 0.84); with dFAST > -0.02, LFC increased (8.6-10.9%, P < 0.05), mean LSM increased by 0.51 kPa, and with dFAST < -0.02, LFC significantly decreased (11.5-8.5%, P < 0.05), mean LSM and NAS decreased by 0.87 kPa and 0.76, respectively (both P < 0.05). CONCLUSIONS: Most models demonstrated good diagnostic and prognostic capabilities for hepatic steatosis, with FAST and KNAFLD showing particular promise as primary non-invasive tools in clinical practice. TRAIL REGISTRATION: Chinese Clinical Trial Registry NO: ChiCTR2100054743, Registered December 26, 2021.

Glycemic control target for liver and cardiovascular events risk in metabolic dysfunction-associated steatotic liver disease.

AIMS: Optimizing glycemic control may prevent liver-related events and major adverse cardiovascular events (MACE) in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). However, the optimal hemoglobin A1c (HbA1c) threshold associated with a lower risk of complications, particularly liver-related events as well as MACE is unknown. METHODS: We investigated a nationwide population-based cohort and identified 633 279 patients with MASLD, with a mean follow-up of 4.2 years. Hemoglobin A1c levels were measured annually. The primary endpoint was the risk of liver-related events and MACE and to determine the optimal HbA1c level associated with the risk of complications. RESULTS: Mean HbA1c (per 1%) was associated with liver-related events (subdistribution hazard ratio [sHR] 1.26; 95% confidence interval [CI], 1.12-1.42) as well as MACE (sHR 1.36; 95% CI, 1.32-1.41) after adjustment for confounders. Multivariable sHR (95% CI) for HbA1c of <5.0%, 6.0%-6.9%, 7.0%-7.9%, 8.0%-8.9%, and ≥9.0% (reference, 5.0%-5.9%) were 14 (9.1-22), 1.70 (1.2-2.3), 3.32 (2.3-4.8), 3.81 (2.1-6.8), and 4.83 (2.4-9.6) for liver-related events, and 1.24 (0.8-1.8), 1.27 (1.2-1.4), 1.70 (1.5-2.0), 2.36 (1.9-2.9), and 4.17 (3.5-5.0) for MACE. An HbA1c level of 7% was selected as the optimal threshold for predicting complications (sHR 2.40 [1.8-3.2] for liver-related events and 1.98 [1.8-2.2] for MACE). CONCLUSION: The risk of liver-related events as well as MACE increased in a dose-dependent fashion with an increase in HbA1c levels, except for patients with HbA1c <5.0% for liver-related events. An HbA1c level of 7% was the optimal threshold associated with a lower risk of complications and may be utilized as a target for glycemic control in patients with MASLD.

Concordance between metabolic dysfunction-associated steatotic liver disease and nonalcoholic fatty liver disease.

AIM: A multisociety consensus group proposed a new nomenclature for metabolic dysfunction-associated steatotic liver disease (MASLD). Although patients with nonalcoholic fatty liver disease (NAFLD) are expected to be reclassified as patients with MASLD under the new nomenclature, the concordance between MASLD and NAFLD remains unclear. Moreover, waist circumference could be adjusted by ethnicity for diagnosing MASLD; however, there are limited data on the optimal waist circumference in the Japanese population. METHODS: This cross-sectional study was conducted on 3709 Japanese patients with NAFLD. The primary endpoint was the prevalence of MASLD in patients with NAFLD. The difference between the original waist circumference criteria (>94 cm for men and >80 cm for women) and the Japanese metabolic syndrome criteria (≥85 cm for men and ≥90 cm for women) for concordance between NAFLD and MASLD was also investigated. RESULTS: According to the original criteria, the prevalence of MASLD in patients with NAFLD was 96.7%. Similarly, according to the Japanese waist circumference criteria, 96.2% of patients with NAFLD could be reclassified as those with MASLD. The concordance rate was significantly higher in the original criteria than in the Japanese criteria (p = 0.02). CONCLUSIONS: NAFLD could be considered MASLD using the original MASLD criteria in the Japanese population, and insights from NAFLD research could be applied to MASLD.

Metabolic dysfunction-associated steatotic liver disease (SLD) and alcohol-associated liver disease, but not SLD without metabolic dysfunction, are independently associated with new onset of chronic kidney disease during a 10-year follow-up period.

AIMS: The new nomenclature of steatotic liver disease (SLD) including metabolic dysfunction-associated SLD (MASLD), MASLD and increased alcohol intake (MetALD), and alcohol-associated liver disease (ALD) has recently been proposed. We aimed to elucidate the relationship between each category of SLD and chronic kidney disease (CKD). METHODS: We investigated the effects of various SLDs on the development of CKD, defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or positive for urinary protein, during a 10-year period in 12 138 Japanese subjects (men / women, 7984/4154; mean age, 48 years) who received annual health examinations including abdominal ultrasonography. RESULTS: The prevalences of SLD without metabolic dysfunction (SLD-MD[-]), MASLD, MetALD, and ALD were 1.7%, 26.3%, 4.9%, and 1.9%, respectively. During the follow-up period, 1963 subjects (16.2%) (men / women, 1374 [17.2%]/589 [14.2%]) had new onset of CKD. Multivariable Cox proportional hazard model analyses after adjustment of age, sex, eGFR, current smoking habit, diabetes mellitus, hypertension, and dyslipidemia showed that the hazard ratios (HR [95% confidence interval]) for the development of CKD in subjects with MASLD (1.20 [1.08-1.33], p = 0.001) and those with ALD (1.41 [1.05-1.88], p = 0.022), but not those with MetALD (1.11 [0.90-1.36], p = 0.332), were significantly higher than the HR in subjects with non-SLD. Interestingly, subjects with SLD-MD[-] had a significantly lower HR (0.61 [0.39-0.96], p = 0.034) than that in subjects with non-SLD. The addition of the novel classification of SLDs into traditional risk factors for the development of CKD significantly improved the discriminatory capacity. CONCLUSIONS: MASLD and ALD, but not SLD-MD[-], are independently associated with the development of CKD.

Deciphering metabolic dysfunction-associated steatotic liver disease: insights from predictive modeling and clustering analysis.

BACKGROUND AND AIM: New nomenclature of steatotic liver disease (SLD) including metabolic dysfunction-associated SLD (MASLD), MASLD and increased alcohol intake (MetALD), and alcohol-associated liver disease (ALD) has recently been proposed. We investigated clustering analyses to decipher the complex landscape of SLD pathologies including the former nomenclature of nonalcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). METHODS: Japanese individuals who received annual health checkups including abdominal ultrasonography (n = 15 788, men/women: 10 250/5538, mean age: 49 years) were recruited. RESULTS: The numbers of individuals with SLD, MASLD, MetALD, ALD, NAFLD, and MAFLD were 5603 (35.5%), 4227 (26.8%), 795 (5.0%), 324 (2.1%), 3982 (25.8%), and 4946 (31.3%), respectively. Clustering analyses using t-distributed stochastic neighbor embedding and K-means to visually represent interconnections in SLDs uncovered five cluster formations. MASLD and NAFLD mainly shared three clusters including (i) low alcohol intake with relatively low-grade obesity; (ii) obesity with dyslipidemia; and (iii) dysfunction of glucose metabolism. Both MetALD and ALD displayed one distinct cluster intertwined with alcohol consumption. MAFLD widely shared all of the five clusters. In machine learning-based analyses using algorithms of random forest and extreme gradient boosting and receiver operating characteristic curve analyses, fatty liver index (FLI), calculated by body mass index, waist circumference, and levels of γ-glutamyl transferase and triglycerides, was selected as a useful feature for SLDs. CONCLUSIONS: The new nomenclature of SLDs is useful for obtaining a better understanding of liver pathologies and for providing valuable insights into predictive factors and the dynamic interplay of diseases. FLI may be a noninvasive predictive marker for detection of SLDs.

Metabolic dysfunction-associated steatotic liver disease: A pathophysiology and clinical framework to face the present and the future.

AIMS: This review aims to provide a straightforward conceptual framework for the knowledge and understanding of Metabolic dysfunction-associated steatotic liver disease (MASLD) in the broad spectrum of steatotic liver disease and to point out the need to consider metabolic dysfunction and comorbidities as interrelated factors for a holistic approach to fatty liver disease. DATA SYNTHESIS: MASLD is the new proposed term for steatotic liver disease that replaces the old terminology of non-alcoholic fatty liver disease. This term focused on the relationship between metabolic alteration and hepatic steatosis, reflecting a growing comprehension of the association between metabolic dysfunction and hepatic steatosis. Numerous factors and conditions contribute to the underlying mechanisms, including central obesity, insulin resistance, adiponectin, lipid metabolism, liver function, dietary influences, the composition of intestinal microbiota, and genetic factors. The development of the condition, however, involves a more intricate network of components, such as neurotensin and Advanced Glycation End Products, highlighting the complexity of its pathogenesis. CONCLUSIONS: MASLD must be regarded as a complex clinical problem in which only a holistic approach can win through the coordination of multi-professional and multi-speciality interventions.

Inhibition of mmu_circ_0009303 improves metabolic dysfunction-associated steatotic liver disease by regulating lipid metabolism and oxidative stress.

Circular RNAs (circRNAs) play an important role in regulating inflammation and oxidative stress during the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD); however, the underlying mechanism is unclear. This study aimed to determine the role of mmu_circ_0009303 in MASLD. We used a bioinformatics approach to identify potential targets and established an in vitro model of MASLD. Oil red O staining, cell transfection and dual-luciferase reporter assay were used to determine the role of mmu_circ_0009303. The results indicated that the mmu_circ_0009303 expression was significantly increased in the MASLD model both in vitro and in vivo and was associated with oxidative stress levels and inflammation. Moreover, bioinformatics analyses revealed that miRNA-182-5p and Foxo3 are targets of mmu_circ_0009303 and miRNA-182-5p, respectively. In the in vitro MASLD model, mmu_circ_0009303 promoted fat deposition in NCTC1469 cells, which was induced by free fatty acid (FFA) through the regulation of miRNA-182-5p/Foxo3. The expression of miRNA-182-5p and Forkhead box O3 (Foxo3) was associated with mmu_circ_0009303 expression in the liver of mice with MASLD, which was induced by a high-fat diet. Furthermore, mmu_circ_0009303 may be involved in regulating the expression of lipid metabolism-related regulatory proteins, such as CPT1A, SLC27A4, ACBD3, SREBP1, FAS, PPARα, and PPARγ. Taken together, mmu_circ_0009303 promotes oxidative stress, inflammation, and excessive fat accumulation in NCTC1469 cells induced by FFA through the regulation of miRNA-182-5p/Foxo3 and lipid metabolism-related regulatory proteins. These findings provide a potential target for the treatment of MASLD.

Between-Visit Reproducibility of Shear Wave Viscoelastography in Volunteers and Patients With Metabolic Dysfunction-Associated Steatotic Liver Disease.

OBJECTIVE: To assess the reproducibility of six ultrasound (US)-determined shear wave (SW) viscoelastography parameters for assessment of mechanical properties of the liver in volunteers and patients with biopsy-proven metabolic dysfunction-associated steatotic liver disease (MASLD) or metabolic dysfunction-associated steatohepatitis (MASH). METHODS: This prospective, cross-sectional, institutional review board-approved study included 10 volunteers and 20 patients with MASLD or MASH who underwent liver US elastography twice, at least 2 weeks apart. SW speed (SWS), Young's modulus (E), shear modulus (G), SW attenuation (SWA), SW dispersion (SWD), and viscosity were computed from radiofrequency data recorded on a research US scanner. Linear mixed models were used to consider the sonographer on duty as a confounder. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC), coefficient of variation (CV), reproducibility coefficient (RDC), and Bland-Altman analyses. RESULTS: The sonographer performing the exam had no impact on viscoelastic parameters (P > .05). ICCs of SWS, E, G, SWA, SWD, and viscosity were, respectively, 0.89 (95% confidence intervals [CI]: 0.79-0.95), 0.81 (95% CI: 0.79-0.95), 0.90 (95% CI: 0.80-0.95), 0.96 (95% CI: 0.93-0.98), 0.78 (95% CI: 0.60-0.89), and 0.90 (95% CI: 0.80-0.95); CVs were 11.9, 23.3, 24.2, 10.1, 29.0, and 32.2%; RDCs were 33.0, 64.5, 66.9, 27.7, 80.3, and 89.2%, and Bland-Altman mean biases and 95% limits of agreement were -0.05 (-0.45, 0.35) m/s, -0.61 (-5.33, 4.10) kPa, -0.25 (-2.06, 1.56) kPa, -0.01 (-0.27, 0.26) Np/m/Hz, -0.09 (-7.09, 6.91) m/s/kHz, and -0.33 (-2.60, 1.94) Pa/s, between the two visits. CONCLUSION: US-determined viscoelastography parameters can be measured with high reproducibility and consistency between two visits 2 weeks apart on the same ultrasound machine.

Non-linear association between long-term air pollution exposure and risk of metabolic dysfunction-associated steatotic liver disease.

BACKGROUND: Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) has become a global epidemic, and air pollution has been identified as a potential risk factor. This study aims to investigate the non-linear relationship between ambient air pollution and MASLD prevalence. METHOD: In this cross-sectional study, participants undergoing health checkups were assessed for three-year average air pollution exposure. MASLD diagnosis required hepatic steatosis with at least 1 out of 5 cardiometabolic criteria. A stepwise approach combining data visualization and regression modeling was used to determine the most appropriate link function between each of the six air pollutants and MASLD. A covariate-adjusted six-pollutant model was constructed accordingly. RESULTS: A total of 131,592 participants were included, with 40.6% met the criteria of MASLD. "Threshold link function," "interaction link function," and "restricted cubic spline (RCS) link functions" best-fitted associations between MASLD and PM2.5, PM10/CO, and O3 /SO2/NO2, respectively. In the six-pollutant model, significant positive associations were observed when pollutant concentrations were over: 34.64 µg/m3 for PM2.5, 57.93 µg/m3 for PM10, 56 µg/m3 for O3, below 643.6 µg/m3 for CO, and within 33 and 48 µg/m3 for NO2. The six-pollutant model using these best-fitted link functions demonstrated superior model fitting compared to exposure-categorized model or linear link function model assuming proportionality of odds. CONCLUSION: Non-linear associations were found between air pollutants and MASLD prevalence. PM2.5, PM10, O3, CO, and NO2 exhibited positive associations with MASLD in specific concentration ranges, highlighting the need to consider non-linear relationships in assessing the impact of air pollution on MASLD.

Unbiased Phosphoproteome Mining Reveals New Functional Sites of Metabolite-Derived PTMs Involved in MASLD Development.

Post-translational modifications (PTMs) of proteins are paramount in health and disease. Phosphoproteome analysis by enrichment techniques is becoming increasingly attractive for biomedical research. Recent findings show co-enrichment of other phosphate-containing biologically relevant PTMs, but these results were obtained by closed searches focused on the modifications sought. Open searches are a breakthrough in high-throughput PTM analysis (OS-PTM), identifying practically all PTMs detectable by mass spectrometry, even unknown ones, with their modified sites, in a hypothesis-free and deep manner. Here we reanalyze liver phosphoproteome by OS-PTM, demonstrating its extremely complex nature. We found extensive Lys glycerophosphorylations (pgK), as well as modification with glycerylphosphorylethanolamine on Glu (gpetE) and flavin mononucleotide on His (fmnH). The functionality of these metabolite-derived PTMs is demonstrated during metabolic dysfunction-associated steatotic liver disease (MASLD) development in mice. MASLD elicits specific alterations in pgK, epgE and fmnH in the liver, mainly on glycolytic enzymes and mitochondrial proteins, suggesting an increase in glycolysis and mitochondrial ATP production from the early insulin-resistant stages. Thus, we show new possible mechanisms based on metabolite-derived PTMs leading to intrahepatic lipid accumulation during MASLD development and reinforce phosphoproteome enrichment as a valuable tool with which to study the functional implications of a variety of low-abundant phosphate-containing PTMs in cell physiology.