Inflammaging is a process of cellular dysfunction associated with chronic inflammation, which plays a significant role in the onset and progression of liver diseases. Research on its mechanisms has become a hotspot. In viral hepatitis, inflammaging primarily involve oxidative stress, cell apoptosis and necrosis, as well as gut microbiota dysbiosis. In non-alcoholic fatty liver disease, inflammaging is more complex, involving insulin resistance, fat deposition, lipid metabolism disorders, gut microbiota dysbiosis, and abnormalities in NAD⁺ metabolism. In liver tumors, inflammaging is characterized by weakening of tumor suppressive mechanisms, remodeling of the liver microenvironment, metabolic reprogramming, and enhanced immune evasion. Therapeutic strategies targeting inflammaging have been developing recently, and antioxidant therapy, metabolic disorder improvement, and immunotherapy are emerging as important interventions for liver diseases. This review focuses on the mechanisms of inflammaging in liver diseases, aiming to provide novel insights for the prevention and treatment of liver diseases.
Humans ; Liver Diseases/pathology* ; Inflammation ; Oxidative Stress ; Non-alcoholic Fatty Liver Disease ; Liver Neoplasms ; Gastrointestinal Microbiome

OBJECTIVE: To investigate the therapeutic potential of pseudolaric acid B (PAB) on non-alcoholic fatty liver disease (NAFLD) and its underlying molecular mechanism in vitro and in vivo. METHODS: Eight-week-old male C57BL/6J mice (n=32) were fed either a normal chow diet (NCD) or a high-fat diet (HFD) for 8 weeks. The HFD mice were divided into 3 groups according to a simple random method, including HFD, PAB low-dose [10 mg/(kg·d), PAB-L], and PAB high-dose [20 mg/(kg·d), PAB-H] groups. After 8 weeks of treatment, glucose metabolism and insulin resistance were assessed by oral glucose tolerance test (OGTT) and insulin tolerance test (ITT). Biochemical assays were used to measure the serum and cellular levels of total cholesterol (TC), triglycerides (TG), aspartate aminotransferase (AST), alanine aminotransferase (ALT), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). White adipose tissue (WAT), brown adipose tissue (BAT) and liver tissue were subjected to hematoxylin and eosin (H&E) staining or Oil Red O staining to observe the alterations in adipose tissue and liver injury. PharmMapper and DisGeNet were used to predict the NAFLD-related PAB targets. Peroxisome proliferator-activated receptor alpha (PPARα) pathway involvement was suggested by Kyoto Encyclopedia of Genes and Genomes (KEGG) and search tool Retrieval of Interacting Genes (STRING) analyses. Luciferase reporter assay, cellular thermal shift assay (CETSA), and drug affinity responsive target stability assay (DARTS) were conducted to confirm direct binding of PAB with PPARα. Molecular dynamics simulations were applied to further validate target engagement. RT-qPCR and Western blot were performed to assess the downstream genes and proteins expression, and validated by PPARα inhibitor MK886. RESULTS: PAB significantly reduced serum TC, TG, LDL-C, AST, and ALT levels, and increased HDL-C level in HFD mice (P<0.01). Target prediction analysis indicated a significant correlation between PAB and PPARα pathway. PAB direct target binding with PPARα was confirmed through luciferase reporter assay, CETSA, and DARTS (P<0.05 or P<0.01). The target engagement between PAB and PPARα protein was further confirmed by molecular dynamics simulations and the top 3 amino acid residues, LEU321, MET355, and PHE273 showed the most significant changes in mutational energy. Subsequently, PAB upregulated the genes expressions involved in lipid metabolism and mitochondrial biogenesis downstream of PPARα (P<0.05 or P<0.01). Significantly, the PPARα inhibitor MK886 effectively reversed the lipid-lowering and PPARα activation properties of PAB (P<0.05 or P<0.01). CONCLUSION PAB mitigates lipid accumulation, ameliorates liver damage, and improves mitochondrial biogenesis by binding with PPARα, thus presenting a potential candidate for pharmaceutical development in the treatment of NAFLD.
Animals ; PPAR alpha/metabolism* ; Non-alcoholic Fatty Liver Disease/pathology* ; Male ; Mice, Inbred C57BL ; Lipid Metabolism/drug effects* ; Diterpenes/therapeutic use* ; Organelle Biogenesis ; Diet, High-Fat ; Humans ; Mice ; Liver/metabolism* ; Insulin Resistance ; Mitochondria/metabolism* ; Molecular Docking Simulation

OBJECTIVES: To investigate the regulatory role of the NLRP3 signaling pathway in hepatocyte pyroptosis in nonalcoholic steatohepatitis (NASH) under hypoxia. METHODS: Twenty-four male C57BL/6 mice were randomized equally into hypoxic control (A), hypoxic NASH model (B), hypoxic NASH+NLRP3 inhibitor (C), and hypoxic NASH+caspase-1 inhibitor (D) groups. In groups B-D, the mice were fed a methionine choline-deficient (MCD) diet under hypoxic conditions (to simulate a 5000 m altitude) for 6 weeks; the mice in groups C and D received intraperitoneal injections of the respective inhibitors every other day. RESULTS: Compared with those in group A, the mice in group B showed significantly elevated serum levels of FBG, TC, TG, ALT and AST, increased liver lipid content, inflammatory cell infiltration and collagen fiber deposition, and enhanced hepatic expressions of NLRP3, caspase-1, IL-1β and GSDMD proteins, with obvious swelling, cristae breakage, vacuolization, and outer membrane disruption of the mitochondria, ribosome loss in the cytoplasm, destruction of the nuclear membrane, and pathological changes of the rough endoplasmic reticulum. Treatment with NLRP3 inhibitor and caspase-1 inhibitor both significantly lowered serum levels of TC, TG, ALT and AST (but without significantly affecting FBG) in the mouse models, and reduced liver lipid content, inflammatory cell infiltration, collagen deposition, and expression levels of NLRP3, caspase-1, GSDMD and IL-1β. The treatments also significantly improved pathological changes in the mitochondria, ribosomes and endoplasmic reticulum in liver tissues of the mice. CONCLUSIONS NLRP3 signaling pathway plays a key role in promoting hepatocyte pyroptosis in NASH mice under hypoxic condition, and inhibiting this pathway can effectively reduce liver inflammation, suggesting its potential as a therapeutic target for NASH treatment.
Animals ; Non-alcoholic Fatty Liver Disease/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Pyroptosis ; Mice, Inbred C57BL ; Male ; Hepatocytes/pathology* ; Signal Transduction ; Mice ; Hypoxia/metabolism* ; Caspase 1/metabolism* ; Interleukin-1beta/metabolism* ; Liver/metabolism*

OBJECTIVES: To identify cuproptosis- and ferroptosis-related genes involved in nonalcoholic fatty liver disease and to determine the diagnostic value of hub genes. METHODS: The gene expression dataset GSE89632 was retrieved from the Gene Expression Omnibus database to identify differentially expressed genes (DEGs) between the non-alcoholic steatohepatitis (NASH) group and the healthy group using the 'limma' package in R software and weighted gene co-expression network analysis. Gene ontology, kyoto encyclopedia of genes and genomes pathway, and single-sample gene set enrichment analyses were performed to identify functional enrichment of DEGs. Ferroptosis- and cuproptosis-related genes were obtained from the FerrDb V2 database and available literatures, respectively. A combined signature for cuproptosis- and ferroptosis-related genes, called CRF, was constructed using the STRING database. Hub genes were identified by overlapping DEGs, WGCNA-derived key genes, and combined signature CRF genes, and validated using the GSE109836 and GSE227714 datasets and real-time quantitative polymerase chain reaction. A nomogram of NASH diagnostic model was established utilizing the 'rms' package in R software based on the hub genes, and the diagnostic value of hub genes was assessed using receiver operating characteristic curve analysis. In addition, immune cell infiltration in NASH versus healthy controls was examined using the CIBERSORT algorithm. The relationships among various infiltrated immune cells were explored with Spearman's correlation analysis. RESULTS: Analysis of GSE89632 identified 236 DEGs between the NASH group and the healthy group. WGCNA highlighted 8 significant modules and 11,095 pivotal genes, of which 330 genes constituted CRF. Intersection analysis identified IL6, IL1B, JUN, NR4A1, and PTGS2 as hub genes. The hub genes were all downregulated in the NASH group, and this result was further verified by the NASH validation dataset and real-time quantitative polymerase chain reaction. Receiver operating characteristic curve analysis confirmed the diagnostic efficacy of these hub genes with areas under the curve of 0.985, 0.941, 1.000, 0.967, and 0.985, respectively. Immune infiltration assessment revealed that gamma delta T cells, M1 macrophages, M2 macrophages, and resting mast cells were predominantly implicated. CONCLUSIONS Our investigation underscores the significant association of cuproptosis- and ferroptosis-related genes, specifically IL6, IL1B, JUN, NR4A1, and PTGS2, with NASH. These findings offer novel insights into the pathogenesis of NASH, potentially guiding future diagnostic and therapeutic strategies.
Non-alcoholic Fatty Liver Disease/pathology* ; Humans ; Ferroptosis/genetics* ; Copper/metabolism* ; Gene Ontology ; Gene Expression Profiling

OBJECTIVES: Over 25% of the global population is affected by metabolic dysfunction-associated fatty liver disease (MAFLD), yet its pathogenesis remains unclear. Endoplasmic reticulum stress (ERS) may be involved in the onset and progression of MAFLD. Adenosine 5'-monophosphate-activated protein kinase α2 (AMPKα2), a key regulator of hepatic energy metabolism, may influence MAFLD development via ERS modulation. This study aims to investigate the role of AMPKα2 in a high-fat diet-induced MAFLD mouse model and its regulatory effect on the inositol-requiring enzyme 1 alpha (IRE1α)-c-Jun N-terminal kinase (JNK) signaling pathway. METHODS: Liver-specific AMPKα2 knockout mice on a C57BL/6 background were generated and subjected to MAFLD induction. Mice were divided into four groups: wild-type control (WT+Chow, basic diet for 12 weeks), wild-type high-fat diet (WT+HFD, high-fat diet for 12 weeks), AMPKα2 knockout control (AMPKα2 KO+Chow), and AMPKα2 knockout high-fat diet (AMPKα2 KO+HFD). Blood glucose, lipid levels, and liver function were assessed post-treatment. Liver histology was analyzed using Oil Red O, hematoxylin-eosin, Masson, and Sirius Red staining. Western blotting was used to evaluate the expression of AMPKα2, ERS markers, autophagy, apoptosis, and ferroptosis-related proteins. RESULTS: Compared with the WT+Chow group, the WT+HFD group showed significantly elevated blood glucose, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels (all P<0.01); histological analyses revealed hepatic steatosis, vacuolization, and fibrosis, with a significantly increased non-alcoholic steatohepatitis activity score (NAS) (P<0.001). Phosphorylated IRE1α and the autophagy marker microtubule-associated protein light chain (LC) 3II/LC3I were markedly upregulated, while apoptotic proteins (Cleaved-Caspase 3, BAX, Bcl-2) and ferroptosis markers (SLC7A11, GPX4) showed no significant change (P>0.05). In the AMPKα2 KO+HFD group, blood glucose, ALT, and AST levels were significantly reduced compared to the WT+HFD group. Histological improvements were observed with reduced vacuolization and lipid accumulation. Expression of p-IRE1α, JNK, and LC3II/LC3I was significantly decreased (P<0.05). CONCLUSIONS Hepatic AMPKα2 knockout alleviates high-fat induced MAFLD, potentially by inhibiting the IRE1α-JNK pathway and reducing autophagy.
Animals ; AMP-Activated Protein Kinases/physiology* ; Protein Serine-Threonine Kinases/metabolism* ; Mice, Knockout ; Diet, High-Fat/adverse effects* ; Mice, Inbred C57BL ; Mice ; Endoplasmic Reticulum Stress ; Endoribonucleases/metabolism* ; Male ; Liver/pathology* ; Non-alcoholic Fatty Liver Disease/metabolism* ; MAP Kinase Signaling System/physiology* ; Fatty Liver/metabolism* ; Signal Transduction

The intestinal mucus layer is a barrier that separates intestinal contents and epithelial cells, as well as acts as the "mucus layer-soil" for intestinal flora adhesion and colonization. Its structural and functional integrity is crucial to human health. Intestinal mucus is regulated by factors such as diet, living habits, hormones, neurotransmitters, cytokines, and intestinal flora. The mucus layer's thickness, viscosity, porosity, growth rate, and glycosylation status affect the structure of the gut flora colonized on it. The interaction between "mucus layer-soil" and "gut bacteria-seed" is an important factor leading to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Probiotics, prebiotics, fecal microbiota transplantation (FMT), and wash microbial transplantation are efficient methods for managing NAFLD, but their long-term efficacy is poor. FMT is focused on achieving the goal of treating diseases by enhancing the "gut bacteria-seed". However, a lack of effective repair and management of the "mucus layer-soil" may be a reason why "seeds" cannot be well colonized and grow in the host gut, as the thinning and destruction of the "mucus layer-soil" is an early symptom of NAFLD. This review summarizes the existing correlation between intestinal mucus and gut microbiota, as well as the pathogenesis of NAFLD, and proposes a new perspective that "mucus layer-soil" restoration combined with "gut bacteria-seed" FMT may be one of the most effective future strategies for enhancing the long-term efficacy of NAFLD treatment.
Humans ; Non-alcoholic Fatty Liver Disease/therapy* ; Gastrointestinal Microbiome ; Probiotics ; Prebiotics ; Fecal Microbiota Transplantation ; Bacteria ; Liver/pathology*

Humans ; Non-alcoholic Fatty Liver Disease/drug therapy* ; Hypoglycemic Agents/therapeutic use* ; Liver Cirrhosis/pathology* ; Biopsy ; Patients ; Liver/pathology* ; Fibrosis

Objective: To investigate the clinical and pathologic characteristics of obese adults with nonalcoholic fatty liver disease (NAFLD) and to aid the diagnosis of nonalcoholic steatohepatitis (NASH). Methods: A total of 262 patients eligible for inclusion who received volume reduction metabolism surgery and liver biopsy in the First Affiliated Hospital of Nanjing Medical University from June 2018 to September 2019 were selected. HE staining, reticular fiber staining and Masson staining were performed. Statistical analysis was performed using SPSS 20.0. Results: The patients ranged in age from 18 to 66 years. Among the 262 cases, 65 cases (65/262, 24.8%) were male and 197 cases (197/262, 75.2%) were female. Sixty-one cases (61/262, 23.3%) were non-NAFLD, 201 cases (201/262, 76.7%) were NAFLD including 27 cases (27/201, 13.4%) of nonalcoholic fatty live (NAFL) and 174 cases (174/201, 86.6%) of NASH. The main lesions of NAFLD were in hepatic acinus zone 3. There were significant differences in age, alanine aminotransferase (ALT), glutamic oxaloacetic transaminase (AST), body mass index (BMI), fasting blood-glucose (FPG) and apolipoprotein A (APOA) levels among the non-NAFLD group, NAFL group and NASH group (P<0.05). Patients with BMI≥35 m/kg² combined with type 2 diabetes had a higher prevalence of NASH. Multiple logistic regression showed that ALT and APOA were independent predictors of NASH (P<0.001, OR=1.05, 95%CI: 1.020-1.082; P=0.027, OR=0.916, 95%CI: 0.878-0.941). Total cholesterol (CHO) and high-density lipoprotein (HDL) were independent predictors of lobular inflammation (P=0.043, 95%CI: 0.010-0.634; P=0.024, 95%CI:-3.068--0.216). AST and HDL were independent predictors of fibrosis stage (P=0.029, 95%CI: 0.001-0.021; P<0.001, 95%CI:-2.670--0.645). Conclusions: Biochemical indicators of NAFLD are closely related to its pathology. The histological lesions of NAFLD are mainly present in hepatic acinar area 3. The diagnosis of NASH is supported by extensive steatosis and high levels of CHO, ALT, AST and BMI, low levels of HDL and ApoA in biochemical markers, but pathological examination is still the gold standard for it.
Adult ; Humans ; Male ; Female ; Adolescent ; Young Adult ; Middle Aged ; Aged ; Non-alcoholic Fatty Liver Disease/pathology* ; Diabetes Mellitus, Type 2/pathology* ; Liver/pathology* ; Obesity/pathology* ; Apolipoproteins A

Objective: To compare the clinical and pathological features of children with chronic viral hepatitis B combined with metabolic-associated fatty liver disease (CHB-MAFLD) and chronic viral hepatitis B alone (CHB alone), and to further explore the effect of MAFLD on the progression of hepatic fibrosis in CHB. Methods: 701 initially treated CHB children confirmed by liver biopsy admitted to the Fifth Medical Center of the PLA General Hospital from January 2010 to December 2021 were collected continuously. They were divided into CHB-MAFLD and CHB-alone groups according to whether they were combined with MAFLD. A retrospective case-control study was conducted. CHB-MAFLD was used as the case group, and 1:2 propensity score matching was performed with the CHB alone group according to age and gender, including 56 cases in the CHB-MAFLD group and 112 cases in the CHB alone group. The body mass index (BMI), metabolic complications, laboratory indicators, and pathological characteristics of liver tissue were compared between the two groups. The related factors affecting liver disease progression in CHB were analyzed by a binary logistic regression model. The measurement data between groups were compared using the t-test and rank sum test. The χ (2) test was used for the comparison of categorical data between groups. Results: Alanine aminotransferase (ALT, P = 0.032) and aspartate aminotransferase (AST, P = 0.003) levels were lower in the CHB-MAFLD group than those in the CHB alone group, while BMI (P < 0.001), triglyceride (TG, P < 0.001), total cholesterol (P = 0.016) and the incidence of metabolic syndrome (P < 0.001) were higher in the CHB alone group. There were no statistically significant differences in HBsAg quantification or HBV DNA load between the two groups (P > 0.05). Histologically, the proportion of significant liver fibrosis (S2-S4) was higher in the CHB-MAFLD group than that in the CHB alone group (67.9% vs. 49.1%, χ (2) = 5.311, P = 0.021). Multivariate regression results showed that BMI (OR = 1.258, 95% CI: 1.145 ~ 1.381, P = 0.001) and TG (OR = 12.334, 95% CI: 3.973 ~ 38.286, P < 0.001) were the risk factors for hepatic steatosis occurrence in children with CHB. MAFLD (OR = 4.104, 95% CI: 1.703 ~ 9.889, P = 0.002), liver inflammation (OR = 3.557, 95% CI: 1.553 ~ 8.144, P = 0.003), and γ-glutamyl transferase (OR = 1.019, 95% CI: 1.001 to 1.038, P = 0.038) were independent risk factors for significant hepatic fibrosis in children with CH. Conclusion: MAFLD occurrence is related to metabolic factors in children with CHB. Additionally, the combination of MAFLD may promote liver fibrosis progression in CHB patients.
Humans ; Child ; Hepatitis B, Chronic/pathology* ; Retrospective Studies ; Case-Control Studies ; Hepatitis B virus/genetics* ; Liver Cirrhosis/pathology* ; Non-alcoholic Fatty Liver Disease/complications* ; Risk Factors

Objective: To detect the therapeutic efficacy of FGF21 analogues on the zebrafish model of non-alcoholic fatty liver disease. Methods: A zebrafish model of non-alcoholic fatty liver disease was established by providing the normal diet fed to wild-type zebrafish three times daily. PF-05231023 was administered exogenously at a final concentration of 0.5 μmol/L. Body length, body weight, triglycerides, and other indexes were measured after 20 days. Pathological changes were evaluated in liver tissue sections by HE staining. Quantitative PCR was used to identify expressional changes in genes related to lipid metabolism, endoplasmic reticulum stress, and inflammation. Results: QPCR and immunofluorescence staining results showed that FGF21 was highly expressed in the zebrafish model group. The addition of the FGF21 analogue PF-05231023 significantly reduced the body length and body weight (P < 0.01), and the triglyceride content (P < 0.05) in the zebrafish model group. The liver HE staining results showed that PF-05231023 had alleviated the large and tiny bullae fat, lesions, and others in the zebrafish model group. The quantitative PCR results demonstrated that PF-05231023 reduced the expression of lipogenic factors (P < 0.01), inflammatory-related factors (P < 0.001), and genes related to endoplasmic reticulum stress (P < 0.05), but raised lipid-oxidation-related factors (P < 0.05) in the zebrafish model group. The addition of PF-05231023 reduced oleic acid-induced lipid and triglyceride levels in HepG2 cells. Conclusion: FGF21 analogue addition can improve indexes in the zebrafish disease model of non-alcoholic fatty liver disease.
Animals ; Body Weight ; Diet, High-Fat ; Lipids ; Liver/pathology* ; Non-alcoholic Fatty Liver Disease/pathology* ; Triglycerides/metabolism* ; Zebrafish/metabolism* ; Zebrafish Proteins