[Research progress in the regulation of pathogenesis and the transformation of chronic liver disease by short-chain fatty acids].

Short-chain fatty acids are metabolites of the intestinal flora and serve as the main energy source for intestinal epithelial cells. At the same time, as important signaling molecules, it regulate a variety of cellular inflammatory responses and homeostatic proliferation through receptor-dependent and independent pathways. Short-chain fatty acids regulate the gut-liver axis and thereby directly act on the liver, participating in the pathogenesis and transformation of various liver diseases, including alcoholic liver disease, metabolic dysfunction-related liver disease, autoimmune liver disease, liver fibrosis, and hepatocellular carcinoma. In addition, short-chain fatty acids can inhibit HBV DNA replication. This article reviews the research progress on the role of short-chain fatty acids in aspects of the pathogenesis and transformation of chronic liver diseases.

Cyclophilin D knockout significantly prevents HCC development in a streptozotocin-induced mouse model of diabetes-linked NASH.

A family of Peptidyl-prolyl isomerases (PPIases), called Cyclophilins, localize to numerous intracellular and extracellular locations where they contribute to a variety of essential functions. We previously reported that non-immunosuppressive pan-cyclophilin inhibitor drugs like reconfilstat (CRV431) or NV556 decreased multiple aspects of non-alcoholic fatty liver disease (NAFLD) in mice under two different non-alcoholic steatohepatitis (NASH) mouse models. Both CRV431 and NV556 inhibit several cyclophilin isoforms, among which cyclophilin D (CypD) has not been previously investigated in this context. It is unknown whether it is necessary to simultaneously inhibit multiple cyclophilin family members to achieve therapeutic benefits or if loss-of-function of one is sufficient. Furthermore, narrowing down the isoform most responsible for a particular aspect of NAFLD/NASH, such as hepatocellular carcinoma (HCC), would allow for more precise future therapies. Features of human diabetes-linked NAFLD/NASH can be reliably replicated in mice by administering a single high dose of streptozotocin to disrupt pancreatic beta cells, in conjunction with a high sugar, high fat, high cholesterol western diet over the course of 30 weeks. Here we show that while both wild-type (WT) and Ppif-/- CypD KO mice develop multipe severe NASH disease features under this model, the formation of HCC nodules was significantly blunted only in the CypD KO mice. Furthermore, of differentially expressed transcripts in a qPCR panel of select HCC-related genes, nearly all were downregulated in the CypD KO background. Cyclophilin inhibition is a promising and novel avenue of treatment for diet-induced NAFLD/NASH. This study highlights the impact of CypD loss-of-function on the development of HCC, one of the most severe disease outcomes.

Epidemiology of NAFLD - Focus on diabetes.

There is increasing appreciation of the complex interaction between nonalcoholic fatty liver disease (NAFLD) with type 2 diabetes (T2D) and insulin resistance. Not only is the prevalence of NAFLD disease high among patients with T2D, the liver disease is also more progressive. Currently, the global prevalence of NAFLD in the general population (2016-2019) is 38 %. The prevalence of T2D among those with NAFLD is approximately 23 % while the prevalence of NAFLD among those with T2D can be as high as 70 %. The prevalence of nonalcoholic steatohepatitis (NASH) is approximately 7 % in the general population and 37 % among patients with T2D. Globally, the MENA and Latin America regions of the world appear to have the highest burden of both NAFLD and T2D. Compared to those with NAFLD but without T2D, those with NAFLD and T2D are at a much higher risk for disease progression to cirrhosis and for decompensated cirrhosis, hepatocellular carcinoma, and all-cause mortality. Given that highly effective new treatments are available for T2D, high risk NAFLD with T2D should be considered for these regimens. This requires implementation of risk stratification algorithms in the primary care and endocrinology practices to identify those patients at highest risk for adverse outcomes.

METTL14 downregulation drives S100A4+ monocyte-derived macrophages via MyD88/NF-κB pathway to promote MAFLD progression.

Without intervention, a considerable proportion of patients with metabolism-associated fatty liver disease (MAFLD) will progress from simple steatosis to metabolism-associated steatohepatitis (MASH), liver fibrosis, and even hepatocellular carcinoma. However, the molecular mechanisms that control progressive MAFLD have yet to be fully determined. Here, we unraveled that the expression of the N6-methyladenosine (m6A) methyltransferase METTL14 is remarkably downregulated in the livers of both patients and several murine models of MAFLD, whereas hepatocyte-specific depletion of this methyltransferase aggravated lipid accumulation, liver injury, and fibrosis. Conversely, hepatic Mettl14 overexpression alleviated the above pathophysiological changes in mice fed on a high-fat diet (HFD). Notably, in vivo and in vitro mechanistic studies indicated that METTL14 downregulation decreased the level of GLS2 by affecting the translation efficiency mediated by YTHDF1 in an m6A-depedent manner, which might help to form an oxidative stress microenvironment and accordingly recruit Cx3cr1+Ccr2+ monocyte-derived macrophages (Mo-macs). In detail, Cx3cr1+Ccr2+ Mo-macs can be categorized into M1-like macrophages and S100A4-positive macrophages and then further activate hepatic stellate cells (HSCs) to promote liver fibrosis. Further experiments revealed that CX3CR1 can activate the transcription of S100A4 via CX3CR1/MyD88/NF-κB signaling pathway in Cx3cr1+Ccr2+ Mo-macs. Restoration of METTL14 or GLS2, or interfering with this signal transduction pathway such as inhibiting MyD88 could ameliorate liver injuries and fibrosis. Taken together, these findings indicate potential therapies for the treatment of MAFLD progression.

Diverse potential of secretome from natural killer cells and monocyte-derived macrophages in activating stellate cells.

Chronic liver diseases, such as non-alcoholic steatohepatitis (NASH)-induced cirrhosis, are characterized by an increasing accumulation of stressed, damaged, or dying hepatocytes. Hepatocyte damage triggers the activation of resident immune cells, such as Kupffer cells (KC), as well as the recruitment of immune cells from the circulation toward areas of inflammation. After infiltration, monocytes differentiate into monocyte-derived macrophages (MoMF) which are functionally distinct from resident KC. We herein aim to compare the in vitro signatures of polarized macrophages and activated hepatic stellate cells (HSC) with ex vivo-derived disease signatures from human NASH. Furthermore, to shed more light on HSC activation and liver fibrosis progression, we investigate the effects of the secretome from primary human monocytes, macrophages, and NK cells on HSC activation. Interleukin (IL)-4 and IL-13 treatment induced transforming growth factor beta 1 (TGF-ß1) secretion by macrophages. However, the supernatant transfer did not induce HSC activation. Interestingly, PMA-activated macrophages showed strong induction of the fibrosis response genes COL10A1 and CTGF, while the supernatant of IL-4/IL-13-treated monocytes induced the upregulation of COL3A1 in HSC. The supernatant of PMA-activated NK cells had the strongest effect on COL10A1 induction in HSC, while IL-15-stimulated NK cells reduced the expression of COL1A1 and CTGF. These data indicate that other factors, aside from the well-known cytokines and chemokines, might potentially be stronger contributors to the activation of HSCs and induction of a fibrotic response, indicating a more diverse and complex role of monocytes, macrophages, and NK cells in liver fibrosis progression.

The fatty liver disease-causing protein PNPLA3-I148M alters lipid droplet-Golgi dynamics.

Nonalcoholic fatty liver disease, recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is a progressive metabolic disorder that begins with aberrant triglyceride accumulation in the liver and can lead to cirrhosis and cancer. A common variant in the gene PNPLA3, encoding the protein PNPLA3-I148M, is the strongest known genetic risk factor for MASLD. Despite its discovery 20 y ago, the function of PNPLA3, and now the role of PNPLA3-I148M, remain unclear. In this study, we sought to dissect the biogenesis of PNPLA3 and PNPLA3-I148M and characterize changes induced by endogenous expression of the disease-causing variant. Contrary to bioinformatic predictions and prior studies with overexpressed proteins, we demonstrate here that PNPLA3 and PNPLA3-I148M are not endoplasmic reticulum-resident transmembrane proteins. To identify their intracellular associations, we generated a paired set of isogenic human hepatoma cells expressing PNPLA3 and PNPLA3-I148M at endogenous levels. Both proteins were enriched in lipid droplet, Golgi, and endosomal fractions. Purified PNPLA3 and PNPLA3-I148M proteins associated with phosphoinositides commonly found in these compartments. Despite a similar fractionation pattern as the wild-type variant, PNPLA3-I148M induced morphological changes in the Golgi apparatus, including increased lipid droplet-Golgi contact sites, which were also observed in I148M-expressing primary human patient hepatocytes. In addition to lipid droplet accumulation, PNPLA3-I148M expression caused significant proteomic and transcriptomic changes that resembled all stages of liver disease. Cumulatively, we validate an endogenous human cellular system for investigating PNPLA3-I148M biology and identify the Golgi apparatus as a central hub of PNPLA3-I148M-driven cellular change.

Competitive adsorption of microRNA-532-3p by circular RNA SOD2 activates Thioredoxin Interacting Protein/NLR family pyrin domain containing 3 pathway and promotes pyroptosis of non-alcoholic fatty hepatocytes.

OBJECTIVE: There is a growing body of evidence indicating that pyroptosis, a programmed cell death mechanism, plays a crucial role in the exacerbation of inflammation and fibrosis in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Circular RNAs (circRNAs), functioning as vital regulators within NAFLD, have been shown to mediate the process of cell pyroptosis. This study aims to elucidate the roles and mechanisms of circRNAs in NAFLD. METHODS: Utilizing a high-fat diet (HFD)-induced rat model for in vivo experimentation and hepatocytes treated with palmitic acid (PA) for in vitro models, we identified circular RNA SOD2 (circSOD2) as our circRNA of interest through analysis with the circMine database. The expression levels of associated genes and pyroptosis-related proteins were determined using quantitative real-time polymerase chain reaction and Western blotting, alongside immunohistochemistry. Serum liver function markers, cellular inflammatory cytokines, malondialdehyde, lactate dehydrogenase levels, and mitochondrial membrane potential, were assessed using enzyme-linked immunosorbent assay, standard assay kits, or JC-1 staining. Flow cytometry was employed to detect pyroptotic cells, and lipid deposition in liver tissues was observed via Oil Red O staining. The interactions between miR-532-3p/circSOD2 and miR-532-3p/Thioredoxin Interacting Protein (TXNIP) were validated through dual-luciferase reporter assays and RNA immunoprecipitation experiments. RESULTS: Our findings demonstrate that, in both in vivo and in vitro NAFLD models, there was an upregulation of circSOD2 and TXNIP, alongside a downregulation of miR-532-3p. Mechanistically, miR-532-3p directly bound to the 3'-UTR of TXNIP, thereby mediating inflammation and cell pyroptosis through targeting the TXNIP/NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling pathway. circSOD2 directly interacted with miR-532-3p, relieving the suppression on the TXNIP/NLRP3 signaling pathway. Functionally, the knockdown of circSOD2 or TXNIP improved hepatocyte pyroptosis; the deletion of miR-532-3p reversed the effects of circSOD2 knockdown, and the deletion of TXNIP reversed the effects of circSOD2 overexpression. Furthermore, the knockdown of circSOD2 significantly mitigated the progression of NAFLD in vivo. CONCLUSION: circSOD2 competitively sponges miR-532-3p to activate the TXNIP/NLRP3 inflammasome signaling pathway, promoting pyroptosis in NAFLD.

Hepatic progenitor cell-originated ductular reaction facilitates liver fibrosis through activation of hedgehog signaling.

Background: It is poorly understood what cellular types participate in ductular reaction (DR) and whether DR facilitates recovery from injury or accelerates hepatic fibrosis. The aim of this study is to gain insights into the role of hepatic progenitor cell (HPC)-originated DR during fibrotic progression. Methods: DR in liver specimens of PBC, chronic HBV infection (CHB) or NAFLD, and four rodent fibrotic models by different pathogenic processes was evaluated. Gli1 expression was inhibited in rodent models or cell culture and organoid models by AAV-shGli1 or treating with GANT61. Results: Severity of liver fibrosis was positively correlated with DR extent in patients with PBC, CHB or NAFLD. HPCs were activated, expanded, differentiated into reactive cholangiocytes and constituted "HPC-originated DR", accompanying with exacerbated fibrosis in rodent models of HPC activation & proliferation (CCl4/2-AAF-treated), Μdr2-/- spontaneous PSC, BDL-cholestatic fibrosis or WD-fed/CCl4-treated NASH-fibrosis. Gli1 expression was significantly increased in enriched pathways in vivo and in vitro. Enhanced Gli1 expression was identified in KRT19+-reactive cholangiocytes. Suppressing Gli1 expression by administration of AAV-shGli1 or GANT61 ameliorated HPC-originated DR and fibrotic extent. KRT19 expression was reduced after GANT61 treatment in sodium butyrate-stimulated WB-F344 cells or organoids or in cells transduced with Gli1 knockdown lentiviral vectors. In contrast, KRT19 expression was elevated after transducing Gli1 overexpression lentiviral vectors in these cells. Conclusions: During various modes of chronic injury, Gli1 acted as an important mediator of HPC activation, expansion, differentiation into reactive cholangiocytes that formed DR, and subsequently provoked hepatic fibrogenesis.

Exosomal miR-122, miR-128, miR-200, miR-298, and miR-342 as novel diagnostic biomarkers in NAFL/NASH: Impact of LPS/TLR-4/FoxO3 pathway.

Nonalcoholic fatty liver disease (NAFLD) is a common liver disorder affecting a quarter of the global residents. Progression of NAFL into nonalcoholic steatohepatitis (NASH) may cause cirrhosis, liver cancer, and failure. Gut microbiota imbalance causes microbial components translocation into the circulation, triggering liver inflammation and NASH-related fibrosis. MicroRNAs (miRNAs) regulate gene expression via repressing target genes. Exosomal miRNAs are diagnostic and prognostic biomarkers for NAFL and NASH liver damage. Our work investigated the role of the gut microbiota in NAFLD pathogenesis via the lipopolysaccharide/toll-like receptor 4/Forkhead box protein O3 (LPS/TLR-4/FoxO3) pathway and certain miRNAs as noninvasive biomarkers for NAFL or its development to NASH. miRNA expression levels were measured using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in 50 NAFL patients, 50 NASH patients, and 50 normal controls. Plasma LPS, TLR-4, adiponectin, peroxisome proliferator-activated receptor γ (PPAR-γ), and FoxO3 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). In NAFL and NASH patients, miR-122, miR-128, FoxO3, TLR-4, LPS, and PPAR-γ were upregulated while miR-200, miR-298, miR-342, and adiponectin were downregulated compared with the normal control. The examined miRNAs might distinguish NAFL and NASH patients from the normal control using receiver operating characteristic analysis. Our study is the first to examine these miRNAs in NAFLD. Our findings imply that these are potentially promising biomarkers for noninvasive early NAFL diagnosis and NASH progression. Understanding the LPS/TLR-4/FoxO3 pathway involvement in NAFL/NASH pathogenesis may aid disease management.

Low vitamin D levels accelerates muscle mass loss in patients with chronic liver disease.

Sarcopenia frequently and progressively occurs in patients with chronic liver disease. This study aimed to clarify the relationship between vitamin D levels and muscle mass loss. A total of 166 patients with chronic liver disease were enrolled in this study. Skeletal muscle mass index (SMI) was measured by bioelectrical impedance analysis at baseline and after 1 year. The rate of change in SMI from baseline after 1 year was calculated: ΔSMI (%) = [(1-year SMI - baseline SMI) / baseline SMI] × 100. Muscle mass loss was defined as ΔSMI ≤ -2%. The median 25-hydroxyvitamin D was 15.2 (11.2-19.3) ng/mL. The median SMI were 6.8 (5.9-7.8) kg/m2 at baseline and 6.7 (5.9-7.6) kg/m2 after 1 year. The median ΔSMI was -1.23% (-2.21% to 1.61%). Multivariate analysis identified low 25-hydroxyvitamin D as an independent factor associated with muscle mass loss. The optimal cut-off value of 25-hydroxyvitamin D to predict muscle mass loss was 12.7 ng/mL. Muscle mass loss was found in 56.4% v.s. 18.0% of patients with 25-hydroxyvitamin D < 12.7 vs. ≥ 12.7 ng/mL, respectively (p = 9.01 × 10-7); with the highest incidence in patients with non-alcoholic fatty liver disease (NAFLD). Specifically, patients with NAFLD and 25-hydroxyvitamin D < 12.7 ng/mL had a significantly higher incidence of muscle mass loss than those with ≥ 12.7 ng/mL (p = 1.23 × 10-3). Low vitamin D levels are associated with muscle mass loss after 1 year in patients with chronic liver disease, especially NAFLD.

Dihydromyricetin ameliorates hepatic steatosis and insulin resistance via AMPK/PGC-1α and PPARα-mediated autophagy pathway.

BACKGROUND: Dihydromyricetin (DHM), a flavonoid compound of natural origin, has been identified in high concentrations in ampelopsis grossedentata and has a broad spectrum of biological and pharmacological functions, particularly in regulating glucose and lipid metabolism. The objective of this research was to examine how DHM affected nonalcoholic fatty liver disease (NAFLD) and its underlying mechanisms involved in the progression of NAFLD in a rat model subjected to a high-fat diet (HFD). Additionally, the study examines the underlying mechanisms in a cellular model of steatohepatitis using palmitic acid (PA)-treated HepG2 cells, with a focus on the potential correlation between autophagy and hepatic insulin resistance (IR) in the progress of NAFLD. METHODS: SD rats were exposed to a HFD for a period of eight weeks, followed by a treatment with DHM (at doses of 50, 100, and 200 mg·kg-1·d-1) for additional six weeks. The HepG2 cells received a 0.5 mM PA treatment for 24 h, either alone or in conjunction with DHM (10 µM). The histopathological alterations were assessed by the use of Hematoxylin-eosin (H&E) staining. The quantification of glycogen content and lipid buildup in the liver was conducted by the use of PAS and Oil Red O staining techniques. Serum lipid and liver enzyme levels were also measured. Autophagic vesicle and autolysosome morphology was studied using electron microscopy. RT-qPCR and/or western blotting techniques were used to measure IR- and autophagy-related factors levels. RESULTS: The administration of DHM demonstrated efficacy in ameliorating hepatic steatosis, as seen in both in vivo and in vitro experimental models. Moreover, DHM administration significantly increased GLUT2 expression, decreased G6Pase and PEPCK expression, and improved IR in the hepatic tissue of rats fed a HFD and in cells exhibiting steatosis. DHM treatment elevated Beclin 1, ATG 5, and LC3-II levels in hepatic steatosis models, correlating with autolysosome formation. The expression of AMPK levels and its downstream target PGC-1α, and PPARα were decreased in HFD-fed rats and PA-treated hepatocytes, which were reversed through DHM treatment. AMPK/ PGC-1α and PPARα knockdown reduced the impact of DHM on hepatic autophagy, IR and accumulation of hepatic lipid. CONCLUSIONS: Our findings revealed that AMPK/ PGC-1α, PPARα-dependent autophagy pathways in the pathophysiology of IR and hepatic steatosis has been shown, suggesting that DHM might potentially serve as a promising treatment option for addressing this disease.

Inflammatory Bowel Diseases and Non-Alcoholic Fatty Liver Disease: Piecing a Complex Puzzle Together.

Inflammatory bowel diseases (IBD), comprising Crohn's disease and ulcerative colitis, are systemic and multifaceted disorders which affect other organs in addition to the gastrointestinal tract in up to 50% of cases. Extraintestinal manifestations may present before or after IBD diagnosis and negatively impact the intestinal disease course and patients' quality of life, often requiring additional diagnostic evaluations or specific treatments. Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. Current evidence shows an increased prevalence of NAFLD (and its more advanced stages, such as liver fibrosis and steatohepatitis) in IBD patients compared to the general population. Many different IBD-specific etiopathogenetic mechanisms have been hypothesized, including chronic inflammation, malabsorption, previous surgical interventions, changes in fecal microbiota, and drugs. However, the pathophysiological link between these two diseases is still poorly understood. In this review, we aim to provide a comprehensive overview of the potential mechanisms which have been investigated so far and highlight open issues still to be addressed for future studies.

Piperine alleviates nonalcoholic steatohepatitis by inhibiting NF-κB-mediated hepatocyte pyroptosis.

PURPOSE: Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD), which has a high risk of cirrhosis, liver failure, and hepatocellular carcinoma. Piperine (Pip) is an extract of plants with powerful anti-inflammatory effects, however, the function of Pip in NASH remains elusive. Here, we aim to explore the role of Pip in NASH and to find the possible mechanisms. METHODS: Methionine and choline-deficient (MCD) diets were used to induce steatohepatitis, methionine- and choline-sufficient (MCS) diets were used as the control. After Pip treatment, H&E staining, Oil Red O staining, hepatic triglyceride (TG) content and F4/80 expression were performed to analysis liver steatosis and inflammation; Masson's staining, COL1A1 and α-SMA were detected liver fibrosis. Lipopolysaccharide (LPS) -treated AML12 cells were used to as the cell model to induce pyroptosis. Then, pyroptosis-related proteins, IL-1ß and LDH release were detected in vivo and in vitro. Finally, NF-κB inhibitor, BAY11-7082, was used to further demonstrate the mechanism of Pip in NASH. RESULTS: The study found that Pip alleviated liver steatosis, inflammation, hepatocyte injury, and fibrosis in mice fed with MCD diets. Moreover, the pyroptosis markers (NLRP3, ASC, caspase-1 p20, and GSDMD), IL-1ß and LDH release were decreased by Pip treatment. NF-κB activation was suppressed by Pip treatment and pyroptosis-related proteins were down regulated by BAY11-7082. CONCLUSION: Pip ameliorates NASH progression, and the therapeutical effect was associated with inhibition of hepatocyte pyroptosis induced by NF-κB.

Molecular pathological approach to cancer epigenomics and its clinical application.

Careful microscopic observation of histopathological specimens, accumulation of large numbers of high-quality tissue specimens, and analysis of molecular pathology in relation to morphological features are considered to yield realistic data on the nature of multistage carcinogenesis. Since the morphological hallmark of cancer is disruption of the normal histological structure maintained through cell-cell adhesiveness and cellular polarity, attempts have been made to investigate abnormalities of the cadherin-catenin cell adhesion system in human cancer cells. It has been shown that the CDH1 tumor suppressor gene encoding E-cadherin is silenced by DNA methylation, suggesting that a "double hit" involving DNA methylation and loss of heterozygosity leads to carcinogenesis. Therefore, in the 1990s, we focused on epigenomic mechanisms, which until then had not received much attention. In chronic hepatitis and liver cirrhosis associated with hepatitis virus infection, DNA methylation abnormalities were found to occur frequently, being one of the earliest indications that such abnormalities are present even in precancerous tissue. Aberrant expression and splicing of DNA methyltransferases, such as DNMT1 and DNMT3B, was found to underlie the mechanism of DNA methylation alterations in various organs. The CpG island methylator phenotype in renal cell carcinoma was identified for the first time, and its therapeutic targets were identified by multilayer omics analysis. Furthermore, the DNA methylation profile of nonalcoholic steatohepatitis (NASH)-related hepatocellular carcinoma was clarified in groundbreaking studies. Since then, we have developed diagnostic markers for carcinogenesis risk in NASH patients and noninvasive diagnostic markers for upper urinary tract cancer, as well as developing a new high-performance liquid chromatography-based diagnostic system for DNA methylation diagnosis. Research on the cancer epigenome has revealed that DNA methylation alterations occur from the precancerous stage as a result of exposure to carcinogenic factors such as inflammation, smoking, and viral infections, and continuously contribute to multistage carcinogenesis through aberrant expression of cancer-related genes and genomic instability. DNA methylation alterations at the precancerous stages are inherited by or strengthened in cancers themselves and determine the clinicopathological aggressiveness of cancers as well as patient outcome. DNA methylation alterations have applications as biomarkers, and are expected to contribute to diagnosis, as well as preventive and preemptive medicine.

Integrative metabolomics highlights gut microbiota metabolites as novel NAFLD-related candidate biomarkers in children.

Altered gut microbiota and metabolites are important for non-alcoholic fatty liver disease (NAFLD) in children. We aimed to comprehensively examine the effects of gut metabolites on NAFLD progression. We performed integrative metabolomics (untargeted discovery and targeted validation) analysis of non-alcoholic fatty liver (NAFL), non-alcoholic steatohepatitis (NASH), and obesity in children. Fecal samples were collected from 75 subjects in the discovery cohort (25 NAFL, 25 NASH, and 25 obese control children) and 145 subjects in an independent validation cohort (53 NAFL, 39 NASH, and 53 obese control children). Among 2,491 metabolites, untargeted metabolomics revealed a complete NAFLD metabolic map containing 318 increased and 123 decreased metabolites. Then, machine learning selected 65 important metabolites that can distinguish the severity of the NAFLD. Furthermore, precision-targeted metabolomics selected 5 novel gut metabolites from 20 typical metabolites. The functionality of candidate metabolites was validated in hepatocyte cell lines. In the end, this study annotated two novel elevated pathogenic metabolites (dodecanoic acid and creatinine) and a relationship between depleted protective gut microbiota (Butyricicoccus and Alistipes), increased inflammation (IL-1ß), lipid metabolism (TG), and liver function (ALT and AST). This study demonstrates the role of novel gut metabolites (dodecanoic acid and creatinine), as the fatty acid metabolism regulator contributing to NAFLD development through its influence on inflammation and liver function. IMPORTANCE: Altered gut microbiota and metabolites are a major cause of non-alcoholic fatty liver disease (NAFLD) in children. This study demonstrated a complete gut metabolic map of children with NAFLD, containing 318 increased and 123 decreased metabolites by untargeted metabolomic. Multiple validation approaches (machine learning and targeted metabolomic) selected five novel gut metabolites for targeted metabolomics, which can distinguish NAFLD status and severity. The gut microbiota (Butyricicoccus and Alistipes) and metabolites (creatinine and dodecanoic acid) were novel biomarkers associated with impaired liver function and inflammation and validated by experiments of hepatocyte cell lines. The data provide a better understanding of the importance of gut microbiota and metabolite alterations in NAFLD, which implies that the altered gut microbiota and metabolites may represent a potential target to prevent NAFLD development.

Correlation between magnetic resonance imaging proton density fat fraction (MRI-PDFF) and liver biopsy to assess hepatic steatosis in obesity.

Obesity is highly associated with Non-alcoholic fatty liver disease (NAFLD) and increased risk of liver cirrhosis and liver cancer-related death. We determined the diagnostic performance of the complex-based chemical shift technique MRI-PDFF for quantifying liver fat and its correlation with histopathologic findings in an obese population within 24 h before bariatric surgery. This was a prospective, cross-sectional, Institutional Review Board-approved study of PDFF-MRI of the liver and MRI-DIXON image volume before bariatric surgery. Liver tissues were obtained during bariatric surgery. The prevalence of NAFLD in the investigated cohort was as high as 94%. Histologic hepatic steatosis grades 0, 1, 2, and 3 were observed in 3 (6%), 25 (50%), 14 (28%), and 8 (16%) of 50 obese patients, respectively. The mean percentages of MRI-PDFF from the anterior and posterior right hepatic lobe and left lobe vs. isolate left hepatic lobe were 15.6% (standard deviation [SD], 9.28%) vs. 16.29% (SD, 9.25%). There was a strong correlation between the percentage of steatotic hepatocytes and MRI-PDFF in the left hepatic lobe (r = 0.82, p < 0.001) and the mean value (r = 0.78, p < 0.001). There was a strong correlation between MRI-derived subcutaneous adipose tissue volume and total body fat mass by dual-energy X-ray absorptiometry, especially at the L2-3 and L4 level (r = 0.85, p < 0.001). MRI-PDFF showed good performance in assessing hepatic steatosis and was an excellent noninvasive technique for monitoring hepatic steatosis in an obese population.

Quantitative ultrasound (QUS) in the evaluation of liver steatosis: data reliability in different respiratory phases and body positions.

Liver steatosis is the most common chronic liver disease and affects 10-24% of the general population. As the grade of disease can range from fat infiltration to steatohepatitis and cirrhosis, an early diagnosis is needed to set the most appropriate therapy. Innovative noninvasive radiological techniques have been developed through MRI and US. MRI-PDFF is the reference standard, but it is not so widely diffused due to its cost. For this reason, ultrasound tools have been validated to study liver parenchyma. The qualitative assessment of the brightness of liver parenchyma has now been supported by quantitative values of attenuation and scattering to make the analysis objective and reproducible. We aim to demonstrate the reliability of quantitative ultrasound in assessing liver fat and to confirm the inter-operator reliability in different respiratory phases. We enrolled 45 patients examined during normal breathing at rest, peak inspiration, peak expiration, and semi-sitting position. The highest inter-operator agreement in both attenuation and scattering parameters was achieved at peak inspiration and peak expiration, followed by semi-sitting position. In conclusion, this technology also allows to monitor uncompliant patients, as it grants high reliability and reproducibility in different body position and respiratory phases.

Association of Histopathological and Biochemical Aspects of NAFLD With the Severity of Liver Fibrosis in Individuals With Obesity: Cross-sectional Study.

BACKGROUND: Given the importance of fibrosis in the progression of non-alcoholic fatty liver disease (NAFLD), identifying biochemical and histopathological aspects associated with its severity is important to determine the course of disease in high-risk populations. OBJECTIVES: The study aims to investigate correlations between biochemical and histopathological variables associated with the occurrence and severity of NAFLD-related liver fibrosis in individuals with obesity. METHODS: This is a cross-sectional study which enrolled 171 individuals who underwent bariatric surgery at a tertiary university hospital. Clinical, laboratory, and histopathological hepatic characteristics were analyzed. Univariate and multivariate analyses were carried out to identify factors associated with the outcomes studied (severity of fibrosis staging) through simple and multiple regression models. RESULTS: Female were 87.7%, and the mean age was 38.4 ± 9.3 years. The most common histopathological abnormalities were macrovesicular steatosis (74.9%) and hepatocellular ballooning (40.4%). In the histopathological univariate analysis, liver fibrosis significantly correlated with severities of microvesicular steatosis (p = 0.003), lobular inflammation (p = 0.001), and NAS (p < 0.001). In the multivariate analysis, the degrees of microvesicular steatosis (p < 0.001) and NAS (p < 0.001) independently correlated with fibrosis severity. In the univariate biochemical analysis, fibrosis severity significantly correlated with levels of hemoglobin A1c (p = 0.004) and glucose (p = 0.01). In the multivariate analysis, glucose levels independently correlated with liver fibrosis degree (p = 0.007). CONCLUSION: Significant and independent associations were observed between the intensities of microvesicular steatosis, NAS, and glucose levels and the severity degree of liver fibrosis in individuals with obesity.

Hepatic danger signaling triggers TREM2+ macrophage induction and drives steatohepatitis via MS4A7-dependent inflammasome activation.

Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (NASH), is an advanced stage of metabolic fatty liver disease. The pathogenic mechanisms of MASH center on hepatocyte injury and the ensuing immune response within the liver microenvironment. Recent work has implicated TREM2+ macrophages in various disease conditions, and substantial induction of TREM2+ NASH-associated macrophages (NAMs) serves as a hallmark of metabolic liver disease. Despite this, the mechanisms through which NAMs contribute to MASH pathogenesis remain poorly understood. Here, we identify membrane-spanning 4-domains a7 (MS4A7) as a NAM-specific pathogenic factor that exacerbates MASH progression in mice. Hepatic MS4A7 expression was strongly induced in mouse and human MASH and associated with the severity of liver injury. Whole-body and myeloid-specific ablation of Ms4a7 alleviated diet-induced MASH pathologies in male mice. We demonstrate that exposure to lipid droplets (LDs), released upon injury of steatotic hepatocytes, triggered NAM induction and exacerbated MASH-associated liver injury in an MS4A7-dependent manner. Mechanistically, MS4A7 drove NLRP3 inflammasome activation via direct physical interaction and shaped disease-associated cell states within the liver microenvironment. This work reveals the LD-MS4A7-NLRP3 inflammasome axis as a pathogenic driver of MASH progression and provides insights into the role of TREM2+ macrophages in disease pathogenesis.

Abnormal metabolism in hepatic stellate cells: Pandora's box of MAFLD related hepatocellular carcinoma.

Metabolic associated fatty liver disease (MAFLD) is a significant risk factor for the development of hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs), as key mediators in liver injury response, are believed to play a crucial role in the repair process of liver injury. However, in MAFLD patients, the normal metabolic and immunoregulatory mechanisms of HSCs become disrupted, leading to disturbances in the local microenvironment. Abnormally activated HSCs are heavily involved in the initiation and progression of HCC. The metabolic disorders and abnormal activation of HSCs not only initiate liver fibrosis but also contribute to carcinogenesis. In this review, we provide an overview of recent research progress on the relationship between the abnormal metabolism of HSCs and the local immune system in the liver, elucidating the mechanisms of immune imbalance caused by abnormally activated HSCs in MAFLD patients. Based on this understanding, we discuss the potential and challenges of metabolic-based and immunology-based mechanisms in the treatment of MAFLD-related HCC, with a specific focus on the role of HSCs in HCC progression and their potential as targets for anti-cancer therapy. This review aims to enhance researchers' understanding of the importance of HSCs in maintaining normal liver function and highlights the significance of HSCs in the progression of MAFLD-related HCC.