The incidence of metabolic dysfunction-associated steatohepatitis (MASH) is increasing, with an incompletely understood pathophysiology involving multiple factors, particularly innate and adaptive immune responses. Given the limited pharmacological treatments available, identification of novel immune metabolic targets is urgently needed. In this study, we aimed to identify hub immune-related genes and potential biomarkers with diagnostic and predictive value for MASH patients.

The GSE164760 dataset from the Gene Expression Omnibus was utilized for analysis, and the R package was used to identify differentially expressed genes. Immune-related differentially expressed genes (IR-DEGs) were identified by comparing the overlap of differentially expressed genes with well-known immune-related genes. Furthermore, the biological processes and molecular functions of the IR-DEGs were analyzed. To characterize the hub IR-DEGs, we employed a protein-protein interaction network. The diagnostic and predictive values of these hub IR-DEGs in MASH were confirmed using GSE48452 and GSE63067 datasets. Finally, the significance of the hub IR-DEGs was validated using a mouse model of MASH.

A total of 91 IR-DEGs were identified, with 61 upregulated and 30 downregulated genes. Based on the protein-protein interaction network, FN1, RHOA, FOS, PDGFRα, CCND1, PIK3R1, CSF1, and FGF3 were identified as the hub IR-DEGs. Moreover, we found that these hub genes are closely correlated with immune cells. Notably, the validation across two independent cohorts as well as a murine MASH model confirmed their high diagnostic potential.

The hub IR-DEGs, such as FN1, RHOA, FOS, PDGFRα, CCND1, PIK3R1, CSF1, and FGF3, may enhance the diagnosis and prognosis of MASH by modulating immune homeostasis.

Metabolic dysfunction-associated steatohepatitis (MASH), the progressed period of metabolic dysfunction-associated steatotic liver disease (MASLD), is a multifaceted liver disease characterised by inflammation and fibrosis that develops from simple steatosis, even contributing to hepatocellular carcinoma and death. MASH involves several immune cell-mediated inflammation and fibrosis, where T cells play a crucial role through the release of pro-inflammatory cytokines and pro-fibrotic factors. This review discusses the complex role of various T cell subsets in the pathogenesis of MASH and highlights the progress of ongoing clinical trials involving T cell-targeted MASH therapies.

To demonstrate that 7-T magnetic resonance imaging (MRI) provides a surrogate for histopathology of fresh ex vivo liver tissue, using the case study of liver fibrosis.

We prospectively enrolled 20 patients undergoing surgical liver resection between November 2021 and April 2023. Each ex vivo fresh liver tissue specimen (~ 1 cm3) was sectioned in half. The first half, stained using Masson's Trichrome and Perls, was assessed by three pathologists using the METAVIR score (reference standard). The second half was imaged with 7-T MRI using a cryoprobe (fat-suppressed T2-weighted turbo/fast spin-echo sequence, spatial resolution 75 × 75 × 200 µm3) and assessed by three radiologists and the same three pathologists, using a newly developed MRI-METAVIR score.

Five patients were excluded from the final analysis (one patient due to poor specimen quality, two due to surgery cancellation, and two previously published used for reader training). Of the remaining 15 patients, 10 (67%) presented with chronic liver diseases and 8/15 (53%) with advanced (F3 or F4) fibrosis. Radiologists achieved 88% sensitivity, 100% specificity, 93% accuracy (95% confidence interval 68-100%) and 0.94 Harrell's c-index (0.86-1.00). Pathologists achieved 88% sensitivity, 86% specificity, 87% accuracy (60-98%) and 0.87 Harrell's c-index (0.74-0.99). There were no statistically significant differences between MRI-based and pathologic reference standard stage (p ≥ 0.655).

With an in-plane spatial resolution of ~ 75 × 75 µm2, MRI paralleled low-magnification histology, enabling the assessment of micro-architectural liver changes, and provided a surrogate for histopathology examination of fresh ex vivo liver tissue samples at a microscopic level.

7-T MRI provides a surrogate for histopathology visualisation of fresh ex vivo liver tissue, opening new research perspectives for clinical high-field MRI of the liver.

Using the newly developed MRI-METAVIR score, 7-T MRI data strongly correlated with histopathology, achieving excellent agreement and accuracy. 7-T MRI accurately differentiated advanced from minimal liver fibrosis. 7-T MRI visualises liver micro-architecture, enabling pathology-like, noninvasive three-dimensional imaging.

Background/Objectives: Metabolic-dysfunction-associated steatotic liver disease (MASLD) progresses from hepatic steatosis to hepatocellular carcinoma (HCC) as a result of systemic immunometabolic dysfunction. This review summarizes the key roles of the innate and adaptive immune mechanisms driving hepatic injury, fibrogenesis, and carcinogenesis in MASLD. Methods: A comprehensive literature review was performed using PubMed to identify relevant published studies. Eligible articles included original research and clinical studies addressing immunological and metabolic mechanisms in MASLD, as well as emerging therapeutic strategies. Results: We highlight the roles of cytokine networks, the gut-liver axis, and immune cell reprogramming. Emerging therapeutic strategies, including cytokine inhibitors, anti-fibrotic agents, metabolic modulators, and nutraceuticals, offer several indications for attenuating MASLD progression and reducing the prevalence of extrahepatic manifestations. Conclusions: Given the heterogeneity of MASLD, personalized combination-based approaches targeting both inflammation and metabolic stress are essential for effective disease management and the prevention of systemic complications.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease worldwide. This study investigates the role of serum miR-548ag in regulating lipid metabolism and its contribution to MASLD in obesity. We found that miR-548ag levels were significantly elevated in the serum of both obese and MASLD patients, and positively correlated with body mass index (BMI), fasting plasma glucose (FPG), triglycerides (TG), total cholesterol (TC), LDL, HDL, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Additionally, miR-548ag expression was significantly higher in the liver and abdominal adipose tissue of obese individuals compared to those of normal weight. In vitro studies in HepG2 and L02 cells, along with previous findings, demonstrated that miR-548ag promotes fatty acid synthase (FASN) expression by inhibiting DNA methyltransferase 3B (DNMT3B), thereby enhancing lipid synthesis. This was confirmed in two mouse models: one with tail vein injections of miR-548ag mimic/inhibitor adeno-associated viruses, and another with tail vein injections of exosomes from serum of normal-weight and obese individuals. Both models showed that miR-548ag upregulated FASN through DNMT3B inhibition, leading to increased lipid synthesis and larger hepatic lipid droplets, effects that were reversed by miR-548ag inhibition. Taken together, elevated miR-548ag expression in obesity enhances hepatic lipid synthesis by targeting DNMT3B to upregulate FASN, contributing to the development of MASLD.

Chronic diseases of the liver are major public health concerns worldwide. Steatosis and steatohepatitis associated with alcoholic liver disease, metabolic dysfunction-associated fatty liver disease/nonalcoholic fatty liver disease, and hepatitis B and C contribute to chronic diseases of the liver. Liver fibrosis occurs in all forms of advanced chronic diseases of the liver, the confirmation of which is typically performed by needle biopsy. Imaging approaches for liver diagnosis exist but do not provide sufficient diagnostic accuracy for defining the various stages of fibrosis or steatosis. Therefore, there is a need for improved imaging capabilities to enhance disease diagnosis. Ultrasonography-based photoacoustic imaging has recently emerged as a noninvasive, nonionizing modality, capable of capturing structural details and oxygen saturation changes during disease progression. However, its potential for detecting surrogate metabolic dysfunction-associated fatty liver disease markers, such as collagen and lipids, which are often poorly resolved by other conventional imaging techniques, has yet to be investigated in detail. The novelty of this study lies in the innovative use of spectral photoacoustic imaging for the direct detection and quantification of key biomarkers of liver disease, such as fibrosis, collagen, lipids, and oxygenated and deoxygenated hemoglobin, in a mouse model of steatotic fatty liver disease. Ultrasonography-based photoacoustic imaging, validated with magnetic resonance imaging, effectively identified increases in liver adiposity and fibrosis, enabling the noninvasive detection of changes in liver pathology associated with metabolic dysfunction.

Cyclic nucleotides are synthesized by adenylyl and/or guanylyl cyclase, and downstream of this synthesis, the cyclic nucleotide phosphodiesterase families (PDEs) specifically hydrolyze cyclic nucleotides. PDEs control cyclic adenosine-3',5'monophosphate (cAMP) and cyclic guanosine-3',5'-monophosphate (cGMP) intracellular levels by mediating their quick return to the basal steady state levels. This often takes place in subcellular nanodomains. Thus, PDEs govern short-term protein phosphorylation, long-term protein expression, and even epigenetic mechanisms by modulating cyclic nucleotide levels. Consequently, their involvement in both health and disease is extensively investigated. PDE inhibition has emerged as a promising clinical intervention method, with ongoing developments aiming to enhance its efficacy and applicability. In this comprehensive review, we extensively look into the intricate landscape of PDEs biochemistry, exploring their diverse roles in various tissues. Furthermore, we outline the underlying mechanisms of PDEs in different pathophysiological conditions. Additionally, we review the application of PDE inhibition in related diseases, shedding light on current advancements and future prospects for clinical intervention. SIGNIFICANCE STATEMENT: Regulating PDEs is a critical checkpoint for numerous (patho)physiological conditions. However, despite the development of several PDE inhibitors aimed at controlling overactivated PDEs, their applicability in clinical settings poses challenges. In this context, our focus is on pharmacodynamics and the structure activity of PDEs, aiming to illustrate how selectivity and efficacy can be optimized. Additionally, this review points to current preclinical and clinical evidence that depicts various optimization efforts and indications.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease, and often progresses to hepatic fibrosis, cirrhosis, and liver failure. Despite its increasing prevalence, effective pharmacological treatments for MASLD-related fibrosis remain limited. Recent research has highlighted AMP-activated protein kinase (AMPK) as a key regulator of the processes that promote fibrogenesis, and AMPK activation shows potential in mitigating fibrosis. Advances in AMPK activators and deeper insights into their role in fibrotic pathways have recently revitalized interest in targeting AMPK for fibrosis treatment. This review discusses the molecular mechanisms linking AMPK to hepatic fibrosis and evaluates emerging AMPK-directed therapies. Furthermore, it addresses challenges in clinical translation. Importantly, we combine the latest mechanistic discoveries with recent therapeutic developments to provide a comprehensive perspective on AMPK as a target for hepatic fibrosis treatment.

Chronic Hepatitis C (CHC) often results in liver fibrosis. Therefore, an important benefit of CHC treatment with direct-acting antiviral (DAA) medication is liver fibrosis regression. However, it is unclear how concurrent liver steatosis affects fibrosis regression following DAA therapy. Recent guidelines have defined liver steatosis associated with metabolic syndrome as metabolic dysfunction-associated steatotic liver disease (MASLD). We sought to examine the association of MASLD with the fibrosis regression benefits of DAA treatment for CHC.

We conducted an observational retrospective analysis using electronic health records of patients aged 18-65 who completed DAA therapy for CHC from 2016 through 2022. FIB-4 scores were calculated during three time periods: just prior to DAA initiation, within 6 months post-DAA completion, and within 6-12 months post-DAA completion. These scores categorized liver fibrosis as high risk (>3.25), intermediate risk (1.45-3.25), or low risk (<1.45). An ordinal logistic regression model assessed the degree of fibrosis regression across these periods in CHC patients with and without MASLD.

We identified 845 patients with CHC who received DAA therapy, of whom 225 met MASLD criteria. Both CHC patients with and without MASLD exhibited a decrease in FIB-4 category (coefficient = -0.361, P < 0.001) within the year following DAA therapy. The reduction in FIB-4 category post-treatment was more pronounced in the MASLD group compared to the non-MASLD group, as evidenced by a significant interaction between group and time period (coefficient = -0.439, P = 0.004).

In our cohort, MASLD was associated with greater liver fibrosis regression in the year following DAA therapy for CHC. This suggests that the concurrent presence of MASLD is not associated with diminished fibrosis regression from DAA therapy. Additional research is needed to determine the exact mechanism responsible for DAA-associated fibrosis regression in patients with MASLD.

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing global health problem and the discovery of drugs is challenging. In this study, we aimed to investigate the effects of intestinal activation of the liver X receptor (LXR)α on MASH. Methods: An intestinal-specific LXRα activation model in mice was established and subjected to MASH development by combining a Western diet and carbon tetrachloride. Lipid metabolism, reverse cholesterol transport (RCT), steatosis, inflammation, and fibrosis were evaluated. In vitro models of steatosis and fibrosis were used to explore the role of scavenger receptor class B type 1 (SRB1). Results: We found that the intestinal activation of LXRα improved several MASLD features, including levels of triglycerides, RCT, steatosis, systemic and hepatic inflammatory profiles, and liver fibrosis. These effects were associated with increased high-density lipoprotein (HDL) levels and hepatic SRB1 expression. In vitro depletion of SRB1 hampered the beneficial effects of HDL on steatosis and fibrogenesis in liver cells by altering the activation of both peroxisome proliferator-activated receptors γ and small mothers against decapentaplegic homolog protein (SMAD)2/3 proteins. Conclusions: Our findings showed that the intestinal activation of LXRα and a parallel induction of hepatic SRB1 are protective against inflammation, steatosis, and advanced liver fibrosis in MASLD.

The increasing prevalence of fibrosis in donor livers raises concerns about its impact on post-transplantation outcomes, though this relationship remains unclear. This study aims to assess the effect of donor liver fibrosis on patient and graft survival following liver transplantation.

Data from the UNOS-SRTR registry (1987-2024) were analyzed, focusing on patients who received liver transplants with biopsy-proven fibrosis. The cohort was stratified based on fibrosis grade, and outcomes were compared using Cox regression and Kaplan-Meier survival analysis. Competing risk models were applied to assess specific causes for graft failure, and subgroup analyses explored the sensitivity of fibrosis on transplant outcomes.

Of the 22,897 patients, 17,926 received non-fibrotic grafts, and 4,971 had grafts with varying fibrosis grades. Donor fibrosis was associated with donor age, steatosis, and portal infiltrate, generally affecting those in better overall condition. Significant differences were observed in patient survival (p = 0.001) and graft survival (p = 0.002) between the fibrosis and non-fibrosis groups. Further analysis revealed that fibrosis increased the risk of malignancy (p = 0.028), cardiovascular disease (p = 0.017), and respiratory failure (p = 0.033), but showed lower rejection rates at six months and one year. Sensitivity analyses confirmed fibrosis as an independent risk factor, with varying effects in subgroups.

Donor liver fibrosis significantly impacts post-transplant outcomes, notably increasing the risk of all-cause mortality and graft failure. Specific causes of death, such as malignancy and cardiovascular disease, were more prevalent in recipients of fibrotic grafts, highlighting the need for further research to refine donor selection criteria.

Background/Objectives: Disrupted glucose uptake, oxidative stress, and increased de novo lipogenesis are some of the key features of metabolic dysfunction-associated fatty liver disease (MASLD). The modulation of these pathogenic mechanisms using extracts from natural and sustainable sources is a promising strategy to mitigate disease progression. This study aimed to evaluate the effects of Prunus domestica L. subsp. syriaca extract on these processes, taking advantage of a cell-based model of steatotic hepatocytes (HepG2-OA) that recapitulates some key pathophysiological features of MASLD. Methods: The HepG2-OA cell model was generated by treating cells for 7 days with 100 μM oleic acid (OA). The effect of different concentrations (0.01, 0.1, 0.5, and 1 mg/mL) of P. domestica extract was assessed through MTT assay (cell viability), flow cytometry (glucose uptake and reactive oxygen species, ROS, production), spectrophotometry (lipid accumulation), and qRT-PCR (expression of selected genes). Results: P. domestica extract exhibited no cytotoxicity at any tested concentration after 24 and 48 h in the HepG2-OA cells. The extract increased glucose uptake in a dose-dependent fashion after both 6 and 24 h. Additionally, the extract reduced lipid accumulation and downregulated the expression of key lipogenic genes (DGAT1 and FASN). Furthermore, in the HepG2-OA cells, P. domestica extract reduced ROS production and downregulated the expression of oxidative stress-related genes (SOD and CAT). Conclusions: P. domestica extract positively modulated some key molecular mechanisms associated with glucose metabolism, lipogenesis, and oxidative stress, supporting its potential as a nutraceutical candidate for MASLD management.

Despite the heavy individual patient and socioeconomic burden of metabolic dysfunction-associated steatohepatitis (MASH), until recently, no pharmacological therapy for MASH was approved, with available treatment options geared towards associated cardiometabolic risk factors. Accelerated approval of resmetirom, a thyroid hormone receptor-β agonist to be used in conjunction with diet and exercise, marks a significant step forward in the treatment of MASH, offering tempered optimism to healthcare providers and millions of patients around the world for more effective management. Evidence from phase 2 and 3 clinical trials suggests that resmetirom has the potential to alleviate hepatic fibrosis and inflammation and significantly reduce liver lipid content. Notwithstanding this landmark event, the clinical implementation of resmetirom comes with important challenges, for example, ensuring patient access to treatment and demonstrating effects on hard MASH-related outcomes, such as progression to cirrhosis and hepatocellular carcinoma. Additional considerations include the evaluation of co-administration with other hepatoprotective treatments and the assessment of the efficacy in specific MASH sub-phenotypes. Furthermore, the accumulation of real-world data and experience is expected to help answer the remaining questions about the (long-term) effectiveness and safety profile of the drug. The purpose of this article is to provide an updated and critical review of the mechanisms of action, efficacy, and safety of resmetirom based on the latest clinical trials, to define its place within the broader landscape of MASH management, and to highlight current knowledge gaps and opportunities for future research in the field.

Hepatocyte-specific deficiency of the phosphatase and tensin homolog (PTEN) triggers steatosis and the development of hepatic tumors. The hepatoprotective effect of PTEN may partly depend on its ability to block insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R) signaling. This study aimed to evaluate the individual/combined contributions of IR and IGF1R to hepatic metabolism and tumorigenesis induced by PTEN deficiency.

Mouse models with hepatocyte-specific deletions of Insr, Igf1r, or both, in addition to Pten, were used to investigate the distinct/combined roles of IR and IGF1R. Analyses focused on the impact of these deletions on hepatic steatosis and metabolism, whole-body adiposity, and liver tumor incidence.

IR and IGF1R signaling contribute to steatosis induced by Pten ablation through distinct mechanisms. Hepatic IGF1R regulates hepatic glucose output and glycogen storage (2.1-fold increase in hepatic glycogen in PTEN-IGF1RKO mice [n = 10], compared with PTENKO mice [n = 7], p <0.0001). In contrast, hepatic IR exerts a stringent regulation on whole-body adiposity (4-fold increase in white adipose tissue volume in PTEN-IRKO mice [n = 5], compared with PTENKO mice [n = 6], p = 0.0004). Interestingly, triple knockout (Insr, Igf1r, and Pten) in hepatocytes of young adult mice is largely asymptomatic, indicating that PTEN deficiency exerts a major overriding control on the effects of Insr and Igf1r deletion. Furthermore, the combined loss of IR and IGF1R signaling in PTEN-deficient livers restrains liver carcinogenesis, but both receptors have individually distinct effects on the malignancy of liver cancers, with IR deficiency reducing overall cancer incidence and IGF1R deficiency promoting malignancy.

These findings increase our understanding of the intricate interplay between PTEN, IR, and IGF1R signaling and provide valuable insights into potential therapeutic interventions in hepatic disorders and hepatocellular carcinoma.

This study underscores the pivotal roles of phosphatase and tensin homolog (PTEN), insulin receptor (IR), and IGF-1 receptor (IGF1R) in controlling liver metabolism, systemic adiposity, and liver cancer progression. Our findings on the distinct and combined effects of these receptors in PTEN-deficient mice offer key insights into the mechanisms driving metabolic dysfunction-associated steatotic liver disease and related hepatocarcinogenesis. In addition, this research reveals the potential of IR and IGF1R as biomarkers in liver cancer development, presenting new opportunities for therapeutic targeting and disease monitoring.

Metabolic dysfunction-associated steatotic liver disease (MASLD) featuring hepatic steatosis and insulin dysregulation is becoming a common cause of chronic hepatic diseases. Although the involvement of endocrine disruption in the onset and progression of MASLD is thought to be critical, there are limited effective animal models reflecting hyperinsulinemia and hepatic steatosis. Here, we propose a MASLD mouse model that combines neuropeptide effects and dietary nutrition. We employed chronic overexpression of the gene encoding neurosecretory protein GL (NPGL) in the hypothalamus of ICR mice under a low-fat/medium-sucrose diet (LFMSD). Npgl overexpression promoted fat accumulation in the white adipose tissues in 2 weeks. Basal insulin levels were increased and pancreatic islets expanded following Npgl overexpression. Histological and molecular biological approaches revealed that Npgl overexpression enhanced de novo lipogenesis, leading to hepatic steatosis. Nine-week overexpression of Npgl exacerbated obesity and hyperinsulinemia, resulting in hyperglycemia. Moreover, prolonged Npgl overexpression aggravated fat accumulation in the liver with a change in the lipid metabolic pathway. These findings suggest that Npgl overexpression readily leads to obesity with hyperinsulinemia and hepatic steatosis in ICR mice under an LFMSD.

There is a significant, rather than just anecdotal, connection between the liver and the eyes. This connection is evident in noticeable cases such as jaundice, where the sclera has a yellow tint. But this can be seen through even more subtle indicators, such as molecules known as hepatokines. This relationship is not merely anecdotal; in some studies, it is referred to as the "liver-eye axis". Ubiquitous environmental contaminants, such as microplastics (MPs), can enter the bloodstream and human body through the conjunctival sac, nasolacrimal duct, and upper respiratory tract mucosa. Once absorbed, these substances can accumulate in various organs and cause harm. Toxic substances from the surface of the eye can lead to local oxidative damage by inducing apoptosis in corneal and conjunctival cells, and irregularly shaped microparticles can exacerbate this effect. Even other toxicants from the ocular surface may be absorbed into the bloodstream and distributed throughout the body. Environmental toxicology presents a challenge because many pollutants can enter the body through the same ocular route as that used by certain medications. Previous research has indicated that the accumulation of MPs may play a major role in the development of chronic liver disease in humans. It is crucial to investigate whether the buildup of MPs in the liver is a potential cause of fibrosis, or simply a consequence of conditions such as cirrhosis and portal hypertension.

Alcohol-associated liver disease (ALD), primarily caused by chronic excessive alcohol consumption, is a leading cause of chronic liver disease worldwide. ALD includes alcohol-associated steatotic liver, alcohol-associated hepatitis (AH), fibrosis, cirrhosis, and can even progress to hepatocellular carcinoma (HCC). Existing research indicates that the risk factors of ALD are quite numerous. In addition to drinking patterns, factors such as aldehyde dehydrogenase 2 (ALDH2) deficiency, smoking, medication administration, high-fat diet (HFD), hepatitis virus infection, and disruption of circadian rhythms can also increase susceptibility to ALD. However, there is limited understanding regarding the exacerbation of liver injury by alcohol plus additional risk factors. This review presents rodent models of EtOH + "X," which simulate the synergistic effects of alcohol and additional risk factors in causing liver injury. These models offer a further exploration of the interactions between alcohol and additional risk factors, advancing the simulation of human ALD and providing a more reliable platform for studying disease mechanisms and exploring therapeutic interventions. We summarize the modeling methods, relevant indicators of liver injury, and focus on the targets of the synergistic effects as well as the associated mechanisms.

Liver sinusoidal endothelial cells (LSECs), with their unique morphology and function, have garnered increasing attention in chronic liver disease research. This review summarizes the critical roles of LSECs under physiological conditions and in two representative chronic liver diseases: metabolic dysfunction-associated steatotic liver disease (MASLD) and liver cancer. Under physiological conditions, LSECs act as selective barriers, regulating substance exchange and hepatic blood flow. Interestingly, LSECs exhibit contrasting roles at different stages of disease progression: in the early stages, they actively resist disease advancement and help restore sinusoidal homeostasis; whereas in later stages, they contribute to disease worsening. During this transition, LSECs undergo capillarization, lose their characteristic markers, and become dysfunctional. As the disease progresses, LSECs closely interact with hepatocytes, hepatic stellate cells, various immune cells, and tumor cells, driving processes such as steatosis, inflammation, fibrosis, angiogenesis, and carcinogenesis. Consequently, targeting LSECs represents a promising therapeutic strategy for chronic liver diseases. Relevant therapeutic targets and potential drugs are summarized in this review.

Helicobacter pylori (H. pylori) infection is a known inducer of various gastrointestinal diseases, including gastritis, gastric ulcers, and gastric cancer. However, in recent years, research on the potential association between H. pylori infection and metabolic dysfunction-associated steatohepatitis (MASH) has been scarce. This large-scale multicenter study, covering more than 360 hospitals across 26 medical systems in the United States, systematically evaluated the association between H. pylori infection and MASH. This paper reviews the innovative aspects of this study, discusses its significance in the current research field of H. pylori and liver diseases, analyzes potential molecular mechanisms, and suggests future research directions and therapeutic prospects.

Macrophages play important roles in metabolic dysfunction-associated steatohepatitis (MASH), an advanced and inflammatory stage of metabolic dysfunction-associated steatotic liver disease (MASLD). In humans and mice, the cellular heterogeneity and diverse function of hepatic macrophages in MASH have been investigated by single cell RNA sequencing (scRNA-seq). However, little is known about their roles in rats. Here, we collected liver tissues at the postnatal week 16, when our previously characterized Lep∆I14/∆I14 rats developed MASH phenotypes. By scRNA-seq, we found an increase in the number of macrophages and endothelial cells and a decrease in that of NK and B cells. Hepatic macrophages in rats underwent a unique M1 to M2 transition without expression of the classical markers such as Arg1 and Nos2, except for Cd163. Lipid-associated macrophages (LAMs) were increased, which could be detected by the antibody against Cd63. In the microenvironment, macrophages had an increased number of interactions with hepatocytes, myofibroblasts, T cells, neutrophils, and dendritic cells, while their interaction strengths remained unchanged. Finally, the macrophage migration inhibitory factor (MIF) pathway was identified as the top upregulated cell-communication pathway in MASH. In conclusion, we dissected hepatic macrophage dynamics during MASH at single cell resolution and provided fundamental tools for the investigation of MASH in rat models.

Hepatic insulin resistance is a fundamental phenomenon observed in both Type 2 diabetes (T2D) and metabolic (dysfunction) associated fatty liver disease (MAFLD). The relative contributions of nutrients, hyperinsulinemia, hormones, inflammation, and other cues are difficult to parse in vivo as they are convoluted by interplay between the local and systemic events. Here, we used a well-established human liver microphysiological system (MPS) to establish a physiologically-relevant insulin-responsive metabolic baseline and probe how primary human hepatocytes respond to controlled perturbations in insulin, glucose, and free fatty acids (FFAs).

Replicate liver MPS were maintained in media with either 200 pM (normal) or 800 pM (T2D) insulin for up to 3 weeks. Conditions of standard glucose (5.5 mM), hyperglycemia (11 mM glucose), normal (20μM) and elevated FFA (100 μM), alone and in combination were used at each insulin concentration, either continuously or reversing back to standard media after 2 weeks of simulated T2D conditions. Hepatic glucose production, activation of signaling pathways, insulin clearance, transcriptome analysis, and intracellular lipid and bile acid accumulation were assessed.

Hyperinsulinemia alone induces insulin resistance after one week of exposure, while hyperglycemia and increased FFAs significantly exacerbate this phenotype. Hyperinsulinemia, along with elevated glucose and FFAs, transcriptionally predisposes hepatocytes to insulin resistance through altered metabolic and immune signaling pathways. The phenotypes observed in hyperinsulinemia and nutrient overload are partially reversible upon return to normophysiologic conditions.

Our enhanced in vitro model, replicating multiple aspects of the insulin-resistant condition, offers improved insights into disease mechanisms with relevance to human physiology.

The incidence of hepatocellular carcinoma (HCC) has been rising, particularly among individuals diagnosed with metabolic dysfunction-associated steatotic liver disease. In the present study, the prophylactic effects of rifaximin (RIF) on HCC, inflammatory markers and cardiovascular risk (CVR) were investigated in an animal model. Adult Sprague-Dawley rats were randomly allocated into three groups (n=10, each): Control [standard diet/water plus gavage with vehicle (Veh)], HCC [high-fat choline deficient diet (HFCD)/diethylnitrosamine (DEN) in drinking water/Veh gavage] and RIF [HFCD/DEN/RIF (50 mg/kg/day) gavage] groups. After euthanasia at week 16, biochemical/inflammatory markers and the liver histology were assessed. The results demonstrated that the HCC and RIF animals had a significant increase in fresh liver weight, liver weight/body weight ratio, serum total cholesterol (TC), high-density lipoprotein-cholesterol, triglycerides, hepatic lipid accumulation and hepatic concentration of triglycerides and TC, relative to the controls (P<0.001, for all). Additionally, the HCC and RIF animals had higher plasminogen activator inhibitor, intercellular adhesion molecule-1, E-selectin and CVR scores than the controls (P<0.001, for all). The HCC animals had higher interleukin (IL)-1β (P=0.011), IL-10 (P<0.001), toll-like receptor-2 (P=0.012), lipopolysaccharide-binding protein (P=0.018) and metalloproteinase-2 (P=0.003) levels than the RIF animals. Furthermore, liver steatosis, inflammation and fibrosis, along with increased collagen fiber deposition occurred in the HCC and RIF groups. However, HCC occurred only in 2 RIF rats. In conclusion, although most animals did not develop HCC in the present study, RIF positively affected liver inflammation markers involved in steatohepatitis pathogenesis.

Metabolic dysfunction-associated steatotic liver disease (MASLD) and opisthorchiasis, caused by Opisthorchis viverrini (O. viverrini) infection, frequently co-exist in Northeast Thailand. However, the underlying pathophysiology remains unknown. We aimed to investigate the effect of a high-fat/high-fructose (HFF) diet combined with O. viverrini infection on MASLD. Four groups each of ten male golden hamsters were established: normal controls (NC), O. viverrini-infected (OV), HFF-fed, and HFF-fed plus O. viverrini infection (HFF+OV). After four months of treatment, histopathological study indicated substantial hepatic damage in groups given the HFF diet. In particular, the HFF+OV group demonstrated marked lipid-droplet accumulation, hepatocyte ballooning, inflammatory-cell clustering, and widespread fibrosis. Biochemical tests indicated that the HFF+OV group had the highest concentrations of alanine aminotransferase and triglycerides, but cholesterol and low-density lipoprotein levels had increased in both HFF groups. Increased expression of Tgf-β1 and α-SMA, indicative of greater fibrosis, was demonstrated by picrosirius-red staining in the HFF+OV group. There was a significant increase in levels of inflammatory markers (HMGB-1, p65, and F4/80) and expression of genes related to the synthesis of fatty acids and glucose. FTIR microspectroscopy revealed distinct changes in fatty acids and proteins, associated with the more pronounced histopathology and impaired liver function in the HFF+OV group. The findings indicate that the interplay of a HFF diet and O. viverrini infection aggravates the progression of MASLD by augmenting liver damage, inflammation, fibrogenesis, and metabolic dysfunction. This study highlights the significance of incorporating both nutritional and infection factors into the management of liver disorders, especially in areas where opisthorchiasis is common.

Liver fibrosis develops in response to chronic liver injury and is characterized by a sustained inflammatory response that leads to excessive collagen deposition by myofibroblasts. The fibrogenic response is governed by the release of inflammatory mediators from innate, adaptive, and innate-like lymphoid cells and from nonprofessional immune cells (i.e., epithelial cells, hepatic myofibroblasts, and liver sinusoidal endothelial cells). Upon removal of the underlying cause, liver fibrosis can resolve via activation of specific immune cell subsets. Despite major advances in the understanding of fibrosis pathogenesis, there is still no approved antifibrotic therapy. This review summarizes our current knowledge of the immune cell landscape and the inflammatory mechanisms underlying liver fibrosis progression and regression. We discuss how reprogramming immune cell phenotype, in particular through targeting selective inflammatory pathways or modulating cell-intrinsic metabolism, may be translated into antifibrogenic therapies.

Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (MASH), is a major risk factor for cirrhosis and hepatocellular carcinoma (HCC) and a leading cause of liver transplantation. MASH is caused by an accumulation of toxic fat molecules in the hepatocyte which leads to inflammation and fibrosis. Inadequate human "MASH in a dish" models have limited our advances in understanding MASH pathogenesis and in drug discovery. This study uses complex multicellular 3D bioprinting, combining hepatocytes with nonparenchymal cells in physiologically relevant cell ratios using biocompatible hydrogels to generate bioinks Bioprinted human liver tissues consisting of the four major cell types, (hepatocytes, liver endothelial cells, Kupffer cells, and hepatic stellate cells) are generated from cells purified from normal human livers, using this complex bioprinting platform. These liver tissues are incubated in a cocktail consisting of fatty acids, lipopolysaccharide (LPS), and fructose to produce a MASH phenotype in comparison to liver tissues incubated in control media. Furthermore, these bioprinted liver tissues are of sufficient size to undergo histological processing and immunohistchemistry comparable to classic clinical pathological analysis. The MASH liver tissues develop hepatocyte steatosis, inflammation, and fibrosis, in response to the MASH induction media. Additionally, the transcriptome of the MASH tissues differed significantly from the healthy tissues and more closely resembled the transcriptome of biopsies of MASH livers from patients Thus, this study has developed a MASH bioprinted liver tissue suitable for studies on pathophysiology and drug discovery.

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the accumulation of triglycerides within hepatocytes, which can progress to more severe conditions, such as metabolic dysfunction-associated steatohepatitis (MASH), which may include progressive fibrosis, leading to cirrhosis, cancer, and death. This goal of this review is to highlight recent research showing the potential of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in reducing the key pathogenic pathways of MASLD or MASH. Methods: Relevant published studies were identified using PubMed with one or more of the following search terms: MASLD, MASH, NAFLD, NASH, exosome, extracellular vesicle (EV), therapy, and/or mesenchymal stem cells (MSC). The primary literature were subsequently downloaded and summarized. Results: Using in vitro or in vivo models, MSC-EVs have been found to counteract oxidative stress, a significant contributor to liver injury in MASH, and to suppress disease progression, including steatosis, inflammation, and, in a few instances, fibrosis. Some of these outcomes have been attributed to specific EV cargo components including microRNAs and proteins. Thus, MSC-EVs enriched with these types of molecules may have improved the therapeutic efficacy for MASLD/MASH and represent a novel approach to potentially halt or reverse the disease process. Conclusions: MSC-EVs are attractive therapeutic agents for treating MASLD/MASH. Further studies are necessary to validate the clinical applicability and efficacy of MSC-EVs in human MASH patients, focusing on optimizing delivery strategies and identifying the pathogenic pathways that are targeted by specific EV components.

The approval of resmetirom brings great hope to patients with metabolic dysfunction-associated steatohepatitis (MASH). The purpose of this review is to explore its impact on the global health environment. The implementation of multidisciplinary management MASH is proposed.

Resmetirom has benefits in the treatment of MASH, and its safety and effectiveness have been studied. The adverse events (AEs) need to be noticed. To improve patient outcomes, a multimodal approach with medication such as resmetirom, combined with metabolic and bariatric surgery (MBS) and lifestyle interventions can be conducted. MASH, a liver disease linked with obesity, is a challenging global healthcare burden compounded by the absence of any approved pharmacotherapy. The recent conditional approval by the Food and Drug Administration (FDA) in the United States of resmetirom, an oral, liver-directed, thyroid hormone receptor beta-selective agonist, marks a significant milestone, offering a treatment option for adults with non-cirrhotic MASH and who have moderate to advanced liver fibrosis. This narrative review discusses the efficacy and safety of resmetirom and its role in the therapeutic landscape of MASH treatment. Despite the promising hepatoprotective effect of resmetirom on histological liver endpoints, its use need further research, particularly regarding ethnic differences, effectiveness and cost-effectiveness, production scalability, social acceptance and accessibility. In addition, integrating resmetirom with other multidisciplinary therapeutic approaches, including lifestyle changes and MBS, might further improve clinical liver-related and cardiometabolic outcomes of individuals with MASH. This review highlights the importance of a comprehensive treatment strategy, supporting continued innovation and collaborative research to refine treatment guidelines and consensus for managing MASH, thereby improving clinical patient outcomes in the growing global epidemic of MASH. Studies done to date have been relatively short and ongoing, the course of the disease is highly variable, the conditions of various patients vary, and given this complex clinical phenotype, it may take many years of clinical trials to show long-term benefits.

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.

Fibrosis is an important pathological feature of endometriotic lesions of all subtypes. Fibrosis is present in and around endometriotic lesions, and a central role in its development is played by myofibroblasts, which are cells derived mainly after epithelial-to-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transdifferentiation (FMT). Transforming growth factor-β (TGF-β) has a key role in this myofibroblastic differentiation. Myofibroblasts deposit extracellular matrix (ECM) and have contracting abilities, leading to a stiff micro-environment. These aspects are hypothesized to be involved in the origin of endometriosis-associated pain. Additionally, similarities between endometriosis-related fibrosis and other fibrotic diseases, such as systemic sclerosis or lung fibrosis, indicate that targeting fibrosis could be a potential therapeutic strategy for non-hormonal therapy for endometriosis.

This review aims to summarize the current knowledge and to highlight the knowledge gaps about the role of fibrosis in endometriosis. A comprehensive literature overview about the role of fibrosis in endometriosis can improve the efficiency of fibrosis-oriented research in endometriosis.

A systematic literature search was performed in three biomedical databases using search terms for 'endometriosis', 'fibrosis', 'myofibroblasts', 'collagen', and 'α-smooth muscle actin'. Original studies were included if they reported about fibrosis and endometriosis. Both preclinical in vitro and animal studies, as well as research concerning human subjects were included.

Our search yielded 3441 results, of which 142 studies were included in this review. Most studies scored a high to moderate risk of bias according to the bias assessment tools. The studies were divided in three categories: human observational studies, experimental studies with human-derived material, and animal studies. The observational studies showed details about the histologic appearance of fibrosis in endometriosis and the co-occurrence of nerves and immune cells in lesions. The in vitro studies identified several pro-fibrotic pathways in relation to endometriosis. The animal studies mainly assessed the effect of potential therapeutic strategies to halt or regress fibrosis, for example targeting platelets or mast cells.

This review shows the central role of fibrosis and its main cellular driver, the myofibroblast, in endometriosis. Platelets and TGF-β have a pivotal role in pro-fibrotic signaling. The presence of nerves and neuropeptides is closely associated with fibrosis in endometriotic lesions, and is likely a cause of endometriosis-associated pain. The process of fibrotic development after EMT and FMT shares characteristics with other fibrotic diseases, so exploring similarities in endometriosis with known processes in diseases like systemic sclerosis, idiopathic pulmonary fibrosis or liver cirrhosis is relevant and a promising direction to explore new treatment strategies. The close relationship with nerves appears rather unique for endometriosis-related fibrosis and is not observed in other fibrotic diseases.

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Stressed hepatocytes promote liver fibrosis through communications with hepatic stellate cells (HSCs) during chronic liver injury. However, intra-hepatocyte players that facilitate such cell-to-cell communications are largely undefined. It is previously reported that hepatocyte E4BP4 is potently induced by ER stress and hepatocyte deletion of E4bp4 protects mice from high-fat diet-induced liver steatosis. Here how hepatocyte E4bp4 deficiency impacts the activation of HSCs and the progression toward MASH-associated liver fibrosis is examined. Hepatic E4BP4 is increased in mouse models of NASH diet- or CCl4-induced liver fibrosis. Hepatocyte-specific E4bp4 deletion protected mice against NASH diet-induced liver injury, inflammation, and fibrosis without impacting liver steatosis. Hepatocyte E4BP4 overexpression activated HSCs in a medium transfer experiment, whereas hepatocyte E4bp4 depletion did the opposite. RNA-Seq analysis identified the pro-fibrogenic factor OPN as a critical target of E4BP4 within hepatocytes. Antibody neutralization or shRNA depletion of Opn abrogated hepatocyte E4BP4-induced HSC activation. E4BP4 interacted with and stabilized YAP, an established activator of OPN. Loss of hepatic Yap blocked OPN induction in the liver of Ad-E4bp4-injected mice. Hepatocyte E4BP4 induces OPN via YAP to activate HSCs and promote liver fibrosis during diet-induced MASH. Inhibition of the hepatocyte E4BP4-OPN pathway could offer a novel therapeutic avenue for treating MASLD/MASH.

The incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) has reached an epidemic rise worldwide. The disease is a constellation of a broad range of metabolic and histopathologic abnormalities. It begins with hepatic steatosis and progresses to metabolic dysfunction-associated steatohepatitis (MASH), including hepatic fibrosis, apoptosis, and cell injury. Despite ample research effort, the pathogenesis of the disease has not been fully delineated. Whereas insulin resistance is implicated in the early stages of the disease, its role in hepatic fibrosis remains controversial. We have focused our studies on the role of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in hepatocytes and endothelial cells in the metabolic and histopathological dysregulation in MASH. Patients with MASH exhibit lower hepatic CEACAM1 with a progressive decline in hepatocytes and endothelial cells as the fibrosis stage advances. In mice, conditional deletion of CEACAM1 in hepatocytes impairs insulin clearance to cause hyperinsulinemia-driven insulin resistance with steatohepatitis and hepatic fibrosis even when mice are fed a regular chow diet. In contrast, its conditional deletion in endothelial cells causes inflammation-driven hepatic fibrosis without adversely affecting metabolism (mice remain insulin-sensitive and do not develop hepatic steatosis). Thus, this review provides in vivo evidence that supports or discards the role of insulin resistance in liver injury and hepatic fibrosis.

Farnesoid X receptor (FXR) is considered a promising therapeutic target for the treatment of metabolic dysfunction-associated steatohepatitis (MASH). Increasing evidence suggests that targeting FXR with full agonists may lead to side effects. FXR partial agonists, which moderately activate FXR signaling, are emerging as a feasible approach to mitigate side effects and address MASH. Herein, a series of novel anthranilic acid derivatives bearing aryloxy moiety were designed and synthesized using a hybrid strategy from the previously identified FXR partial agonists DM175 and AIV-25. Particularly, compound 26 exhibited potent FXR partial agonistic activity in a dual-luciferase reporter gene assay with an EC50 value of 0.09 ± 0.02 µM (75.13 % maximum efficacy relative to OCA). In the MASH mice model, compound 26 significantly ameliorated the pathological features of the liver, including steatosis, inflammation, and fibrosis. In addition, compound 26 displayed high selectivity, good oral bioavailability, high liver distribution, as well as an acceptable safety profile. Molecular simulation studies showed that compound 26 fitted well with the binding site of FXR. Collectively, these findings demonstrated that compound 26 might serve as a promising candidate targeting FXR for MASH treatment.

Sialic acids are located on the ends of many glycoconjugates and are cleaved off by enzymes called sialidases (neuraminidases). Upregulation of neuraminidase 3 (NEU3) is associated with intestinal inflammation and colitis, neuroinflammation, and lung fibrosis. Genetic ablation of NEU3 or pharmacological inhibition of NEU3 reduces lung fibrosis in mice. To determine if inhibiting NEU3 can inhibit liver fibrosis in the commonly-used CCl4 model, in this report, we examined the effects of injections of the NEU3 inhibitor 2-acetyl pyridine (2AP). 2AP inhibited CCl4-induced weight loss in female but not male mice. 2AP attenuated CCl4-induced liver inflammation and fibrosis in male and female mice, but did not affect CCl4-induced steatosis. After CCl4 treatment, female but not male mice had significant increases in liver neutrophils, and 2AP attenuated this response. 2AP also reversed CCl4-induced liver desialylation and CCl4-induced increased expression of NEU3. Patients with pulmonary fibrosis have increased desialylation of some serum proteins, and elevated serum levels of NEU3. We find that sera from patients with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) have elevated desialylation of a serum protein and patients with NAFLD have increased levels of NEU3. These data suggest that elevated levels of NEU3 may be associated with liver inflammation and fibrosis, and that in mice this is ameliorated by injections of a NEU3 inhibitor.

Fibrosis results from the excessive production of extracellular matrix proteins by myofibroblasts. It has recently been reported that in the heart, myofibroblasts develop chondrocyte-like properties following myocardial infarction as fibrosis progresses and tissues stiffen. However, the nature of these chondrocyte-like myofibroblasts remains unclear. In this study, we found that the expression of the proline- and arginine-rich end leucine-rich repeat protein (PRELP) was upregulated in hearts and livers stiffened by fibrosis with chronic inflammation. Moreover, we established that Prelp was specifically expressed in chondrocyte-like myofibroblasts. Prelp expression was found to be regulated by the transcription factor SOX9, and in cardiac and liver myofibroblasts, Prelp-knockdown was observed to reduce collagen expression. These findings reveal that PRELP is specifically expressed in chondrocyte-like myofibroblasts and that it promotes collagen production. PRELP could thus serve as a novel therapeutic target for treating fibrosis.

Mitochondrial calcium uniporter (MCU) plays pleiotropic roles in cellular physiology and pathology that contributes to a variety of diseases, but the role and potential mechanism of MCU in the pathogenesis of metabolic dysfunction-associated steatohepatitis (MASH) remain poorly understood.

Here, hepatic knockdown of MCU in C57BL/6J mice was achieved by tail vein injection of AAV8-mediated the CRISPR/Cas9. Mice were fed a Choline-deficient, L-amino acid-defined high-fat diet (CDAHFD) for 8 weeks to induce MASH and fibrosis. We find that expression of MCU enhanced in MASH livers of humans and mice. MCU knockdown robustly limits lipid droplet accumulation, steatosis, inflammation, and hepatocyte apoptotic death during MASH development both in vivo in mice and in vitro in cellular models. MCU-deficient mice strikingly mitigate MASH-related fibrosis. Moreover, the protective effects of MCU knockdown against MASH progression are accompanied by a reduced level of mitochondrial calcium, limiting hepatic oxidative stress, and attenuating mitochondrial dysfunction. Mechanically, RNA sequencing analysis and protein immunoblotting indicate that knockdown MCU inhibited the Hippo/YAP pathway activation and restored the AMP-activated protein kinase (AMPK) activity during MASH development both in vitro and in vivo.

MCU is up-regulated in MASH livers in humans and mice; and hepatic MCU knockdown protects against diet-induced MASH and fibrosis in mice. Thus, targeting MCU may represent a novel therapeutic strategy for MASH and fibrosis.

The rise in obesity highlights the need for improved therapeutic strategies, particularly in addressing metabolic dysfunction-associated steatotic liver disease (MASLD). We aim to assess the role of tryptophan metabolic pathways in the pathogenesis of obesity and in the different histological stages of MASLD.

We used ultra-high performance liquid chromatography to quantify circulating levels of 15 tryptophan-related metabolites from the kynurenine, indole and serotonin pathways. A cohort of 76 subjects was analysed, comprising 18 subjects with normal weight and 58 with morbid obesity, these last being subclassified into normal liver (NL), simple steatosis (SS) and metabolic dysfunction-associated steatohepatitis (MASH). Then, we conducted gene expression analysis of hepatic IDO-1 and kynyrenine-3-monooxygenase (KMO).

Key findings in obesity revealed a distinct metabolic signature characterized by a higher concentration of different kynurenine-related metabolites, a decrease in indole-3-acetic acid and indole-3-propionic acid, and an alteration in the serotonin pathway. Elevated tryptophan levels were associated with MASLD presence (37.659 (32.577-39.823) μM of tryptophan in NL subjects; 41.522 (38.803-45.276) μM in patients with MASLD). Overall, pathway fluxes demonstrated an induction of tryptophan catabolism via the serotonin pathway in SS subjects and into the kynurenine pathway in MASH. We found decreased IDO-1 and KMO hepatic expression in NL compared to SS.

We identified a distinctive metabolic signature in obesity marked by changes in tryptophan catabolic pathways, discernible through altered metabolite profiles. We observed stage-specific alterations in tryptophan catabolism fluxes in MASLD, highlighting the potential utility of targeting these pathways in therapeutic interventions.