Tumor necrosis factor-α-mediated hepatocyte apoptosis stimulates fibrosis in the steatotic liver in mice

Standardized evaluation of diabetic retinopathy using artificial intelligence and its association with metabolic dysfunction-associated steatotic liver disease in Japan: A cross-sectional study

Metabolic dysfunction-associated steatotic liver disease (MASLD) is common in patients with obesity and diabetes and can lead to serious complications. This study aimed to evaluate fundus photographs using artificial intelligence to explore the relationships between diabetic retinopathy (DR), MASLD, and related factors. In this cross-sectional study, we included 1,736 patients with a history of diabetes treatment or glycated hemoglobin (HbA1c) levels of ≥6.5%. All participants were negative for hepatitis B surface antigen and hepatitis C virus antibody and were selected from 33,022 examinees at a health facility in Japan. Fundus photographs were analyzed using RetCAD software, and DR scores were quantified. The presence of DR was determined using two cutoffs: sensitivity (CO20) and specificity (CO50). Steatotic liver (SL) stages were assessed via ultrasound and fibrosis indices and classified into three groups: no SL (SL0), SL with low fibrosis (SL1), and SL with high fibrosis (SL2). Odds ratios (ORs) for the risk of DR associated with each SL stage were calculated using logistic regression, adjusted for age, sex, body mass index, HbA1c, C-reactive protein level, and alcohol consumption. The risk of DR was lower in the SL1 (OR: 0.63, 0.54) and SL2 (OR: 0.64, 0.77) groups compared to the SL0 group at CO20 for both the Fibrosis-4 Index (FIB-4) and the non-alcoholic fatty liver disease fibrosis score (NFS), respectively. Additionally, higher levels of cholinesterase were consistently associated with a reduced risk of DR (FIB-4: OR 0.52, NFS: OR 0.54) at CO50. This study demonstrates that MASLD was associated with a reduced risk of DR, with cholinesterase levels providing further protective effects, highlighting the need for further research into the protective mechanisms and refinement of DR evaluation techniques. The standardized AI evaluation method for DR offers a reliable approach for analyzing retinal changes.

The potential of flavonoids in hepatic fibrosis: A comprehensive review

BACKGROUND

Hepatic fibrosis is a pathophysiological process of extracellular matrix abnormal deposition induced by multiple pathogenic factors. Currently, there is still a lack of effective and non-toxic drugs for treating fibrosis in clinic. Flavonoids are polyphenolic compounds synthesized in plants and modern pharmacological studies confirmed flavonoids exhibit potent hepatoprotective effect.

PURPOSE

Summarize literature to elaborate the mechanism of HF and evaluate the potential of flavonoids in HF, aiming to provide a new perspective for future research.

METHODS

The literatures about hepatic fibrosis and flavonoids are collected via a series of scientific search engines including Google Scholar, Elsevier, PubMed, CNKI, WanFang, SciFinder and Web of Science database. The key words are "flavonoids", "hepatic fibrosis", "pharmacokinetic", "toxicity", "pathogenesis" "traditional Chinese medicine" and "mechanism" as well as combination application.

RESULTS

Phytochemical and pharmacological studies revealed that about 86 natural flavonoids extracted from Chinese herbal medicines possess significantly anti-fibrosis effect and the mechanisms maybe through anti-inflammatory, antioxidant, inhibiting hepatic stellate cells activation and clearing activated hepatic stellate cells.

CONCLUSIONS

This review summarizes the flavonoids which are effective in HF and the mechanisms in vivo and in vitro. However, fewer studies are focused on the pharmacokinetics of flavonoids in HF model and most studies are limited to preclinical studies, therefore there is no reliable data from clinical trials for the development of new drugs. Further in-depth research related it can be conducted to improve the bioavailability of flavonoids and serve the development of new drugs.

Ginsenoside Rg5 inhibits lipid accumulation and hepatocyte apoptosis via the Notch1 signaling pathway in NASH mice

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a prevalent chronic liver disease that lacks an FDA-approved treatment medicine. Despite the known antitumor and hypoglycemic properties of Ginsenoside Rg5, its effects and underlying mechanisms in the context of NASH remain largely unexplored.

PURPOSE

This study aims to investigate the effect of Rg5 on NASH mice induced by a high-fat diet and CCl4.

STUDY DESIGN

In vivo experiments, a mouse NASH model was established by a HFHC diet plus intraperitoneal injection of low-dose CCl4. In vitro experiments, a cellular steatosis model was established using free fatty acids (FFA) induced HepG2 cells. In addition, a fibrogenesis model was established using HSC-LX2 cells.

METHODS

The effects of Ginsenoside Rg5 on lipid accumulation and oxidative damage were analyzed by ELISA kit, H&E staining, Oil Red O staining, flow cytometry and Western blot. The effects of Ginsenoside Rg5 on liver fibrosis were analyzed by Masson staining, Sirus Red staining, immunohistochemistry and Western blot. The effect of Ginsenoside Rg5 on Notch1 signaling pathway in liver was studied by protein Oil Red staining, protein immunoblotting and immunofluorescence.

RESULTS

In terms of lipid accumulation, Rg5 has the ability to regulate key proteins related to lipogenesis, thereby inhibiting hepatic lipid accumulation and oxidative stress. Additionally, Rg5 can reduce the occurrence of hepatocyte apoptosis by regulating the p53 protein. Moreover, after Rg5 intervention, the presence of fibrotic proteins (α-SMA, Collagen 1, TGF-β) in the liver is significantly suppressed, thus inhibiting liver fibrosis. Lastly, Rg5 leads to a decrease in the expression levels of Notch1 and its ligand Jagged-1 in the liver.

CONCLUSION

In summary, the regulatory effects of Rg5 on the Notch1 signaling pathway play a crucial role in modulating hepatic lipid metabolism and preventing hepatocyte apoptosis, thereby impeding the progression of NASH. These findings highlight the potential of Rg5 as a promising natural product for interventions targeting NASH.

Induction of the Lipid Droplet Formation Genes in Steatohepatitis Mice by Embryo/Postnatal Nutrient Environment Is Associated with Histone Acetylation around the Genes

Recently, we have demonstrated that mice, cultured embryos in α-minimum essential medium (αMEM) and subsequent fed a high-fat, high-sugar diet, developed steatohepatitis. In this study, we investigated using these samples whether the expression of lipid droplet formation genes in the liver is higher in MEM mice, whether these expressions are regulated by histone acetylation, writers/readers of histone acetylation, and the transcriptional factors of endoplasmic reticulum stress. Mice were produced by two-cell embryos in αMEM or standard potassium simplex-optimized medium (control) in vitro for 48 h, and implanted into an oviduct for spontaneous delivery. MEM and control-mice were fed a high-fat, high-sugar diet for 18 wk, and then liver samples were collected and analyzed by histology, qRT-PCR, and chromatin immunoprecipitation assay. Gene expression of Cidea, Cidec, and Plin4 were higher in MEM mice and histone H3K9 acetylation, BRD4, and CBP were higher in MEM mice than in control mice around those genes. However, the binding of endoplasmic reticulum stress-related transcription factors (ATF4, CHOP and C/EBPα) around those genes in the liver, was not clearly differed between MEM mice and control mice. The increased expression of Cidea, Cidec and Plin4 in the liver, accompanied by the development of steatohepatitis in mice induced is positively associated with increased histone H3K9 acetylation and CBP and BRD4 binding around these genes.

Transcription Factor Forkhead Box O1 Mediates Transforming Growth Factor-β1-Induced Apoptosis in Hepatocytes

Dysregulation of hepatocyte apoptosis is associated with several types of chronic liver diseases. Transforming growth factor-β1 (TGF-β1) is a well-known pro-apoptotic factor in the liver, which constitutes a receptor complex composed of TGF-β receptor I and II, along with transcription factor Smad proteins. As a member of the forkhead box O (Foxo) class of transcription factors, Foxo1 is a predominant regulator of hepatic glucose production and apoptosis. This study investigated the potential relationship between TGF-β1 signaling and Foxo1 in control of apoptosis in hepatocytes. TGF-β1 induced hepatocyte apoptosis in a Foxo1-dependent manner in hepatocytes isolated from both wild-type and liver-specific Foxo1 knockout mice. TGF-β1 activated protein kinase A through TGF-β receptor I-Smad3, followed by phosphorylation of Foxo1 at Ser273 in promotion of apoptosis in hepatocytes. Moreover, Smad3 overexpression in the liver of mice promoted the levels of phosphorylated Foxo1-S273, total Foxo1, and a Foxo1-target pro-apoptotic gene Bim, which eventually resulted in hepatocyte apoptosis. The study further demonstrated a crucial role of Foxo1-S273 phosphorylation in the pro-apoptotic effect of TGF-β1 by using hepatocytes isolated from Foxo1-S273A/A knock-in mice, in which the phosphorylation of Foxo1-S273 was disrupted. Taken together, this study established a novel role of TGF-β1→protein kinase A→Foxo1 signaling cascades in control of hepatocyte survival.

The effects of pentoxifylline and caffeic acid phenethyl ester on TNF-α and lung histopathology in D-galactosamine-induced pulmonary injury in rats

In this study, we aimed to investigate the effects of pentoxifylline [PTX] and caffeic acid phenethyl ester [CAPE] in D-galactosamine [D-GAL]-induced pulmonary injury in rats. The rats were randomly divided into six groups: control, D-GAL, D-GAL+PTX, D-GAL+CAPE, PTX and CAPE. Each group included eight animals. Lung sections from the control, PTX and CAPE groups had a normal histological appearance. The D-GAL group showed histopathological changes in lung tissue, including haemorrhage, oedema, inter-alveolar septal thickening and widespread infiltration of inflammatory lymphocytes and macrophages. Administration of PTX and CAPE significantly reduced histopathological damage scores in the D-GAL+PTX and D-GAL+CAPE groups compared with the D-GAL group. PTX and CAPE treatment also significantly decreased malondialdehyde levels, increased levels of reduced GSH and increased catalase and superoxide dismutase activity in lung tissue samples. These results indicate that the destructive effects of D-GAL-induced inflammation in the rat lung are significantly reduced following administration of PTX and CAPE.

Divergent effect of Birinapant, and BV6 SMAC mimetic on TNFα induced NF-κB signaling and cell viability in activated hepatic stellate cells

BACKGROUND

Tumor necrosis factor-α (TNFα) is a pleiotropic cytokine involved in nuclear factor kappa B (NF-κB) mediated cell survival as well as cell death. High serum TNFα levels correlate with liver fibrosis and enhance hepatic stellate cell (HSC) viability. However, the regulatory role of cellular inhibitor of apoptosis-1/2 (cIAP1/2) during TNFα induced NF-κB signaling in activated HSCs is largely unknown.

METHOD AND RESULTS

Activated HSCs were treated with cIAP1/2 inhbitiors i.e., SMAC mimetic BV6, and Birinapant in the presence of TNFα and macrophage conditioned media. TNFα cytokine increased cIAP2 expression and enhanced cell viability through the canonical NF-κB signaling in activated HSCs. cIAP2 inhibition via BV6 decreased the TNFα induced canonical NF-κB signaling, and reduced cell viability in activated HSCs. SMAC mimetic, Birinapant alone did not affect the cell viability but treatment of TNFα sensitized HSCs with Birinapant induced cell death. While BV6 mediated cIAP2 ablation was able to decrease the TNFα induced canonical NF-κB signaling, this effect was not observed with Birinapant treatment. Secreted TNFα from M1 polarized macrophages sensitized activated HSCs to BV6 or Birinapant mediated cell death. However, M2 polarized macrophage conditioned medium rescued the activated HSCs from BV6 mediated cytotoxicity.

CONCLUSION

In this study, we describe the regulatory role of cIAP2 in TNFα induced NF-κB signaling in activated HSCs. Targeting cIAP2 may be a promising approach for liver fibrosis treatment via modulating NF-κB signaling in activated HSCs.

Heterogeneous population of macrophages in the development of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by a spectrum of hepatic diseases, including fatty liver, non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. NAFLD is a hepatic manifestation of metabolic syndrome and has become the leading cause of liver transplantation, necessitating an in-depth understanding of its underlying pathogenic mechanisms and the identification of viable drug targets. Although fatty liver is benign and does not exert marked liver damage or inflammation, NAFLD progression involves inflammatory processes facilitated by immune cells. Macrophages and monocytes constitute the pool of innate immune cells that contribute to NAFLD development in association with other cell types, such as neutrophils, T cells, and natural killer cells. The concept that macrophages contribute to the inflammatory processes in NAFLD development has long been debated; however, the remarkable advances in experimental techniques have rapidly uncovered new subpopulations of macrophages and monocytes, whose functions need to be comprehensively elucidated. The current review focuses on the recent expansion of our knowledge of the heterogeneous population of macrophages crucially involved in NAFLD development. In addition, the present paper discusses ongoing efforts to target macrophages and inflammatory processes to develop optimal therapeutic agents against non-alcoholic steatohepatitis.

The capsaicinoid nonivamide suppresses the inflammatory response and attenuates the progression of steatosis in a NAFLD-rat model

Nonalcoholic fatty liver disease (NAFLD) is relatively associated with comorbidities in obesity and metabolic inflammation. Low-grade inflammation following the high-fat diet (HFD)-induced NAFLD can promote the development of nonalcoholic steatohepatitis (NASH) through particularly liver-resident immune cell recruitment and hepatic nuclear factor kappa B (NF-κB) pathway. Therefore, inflammatory intervention may contribute to NASH reduction. Pelargonic acid vanillylamide (PAVA) or nonivamide is one of the pungent capsaicinoids of Capsicum species and has been found in chili peppers. Our previous study demonstrated that PAVA improved hepatic function, decreased oxidative stress and reduced apoptotic cell death but the insight role of PAVA on NAFLD is still unclear. Thus, this study aimed to investigate the underlying anti-inflammatory mechanism of PAVA in an NAFLD-rat model. Male Sprague Dawley rats were fed with normal diet or HFD for 16 weeks. Then high-fat rats were given vehicle or PAVA (1 mg/kg/day) for another 4 weeks. We found that PAVA alleviated hepatic inflammation associated with the reducing toll-like receptor 4/NF-κB pathway, showing significantly lower recruitment of cluster of differentiation 44. PAVA also maintained activity of insulin signaling pathway, and attenuated NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome formation. NAFLD progresses to NASH through transforming growth factor (TGF-β1), and also recovery to simple stage followed by PAVA suppresses pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β, interleukin-6, and Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway. Therefore, our findings suggest that PAVA provides a novel therapeutic approach for NAFLD and slows the progression to NASH.

The identification of metabolites from gut microbiota in NAFLD via network pharmacology

The metabolites of gut microbiota show favorable therapeutic effects on nonalcoholic fatty liver disease (NAFLD), but the active metabolites and mechanisms against NAFLD have not been documented. The aim of the study was to investigate the active metabolites and mechanisms of gut microbiota against NAFLD by network pharmacology. We obtained a total of 208 metabolites from the gutMgene database and retrieved 1256 targets from similarity ensemble approach (SEA) and 947 targets from the SwissTargetPrediction (STP) database. In the SEA and STP databases, we identified 668 overlapping targets and obtained 237 targets for NAFLD. Thirty-eight targets were identified out of those 237 and 223 targets retrieved from the gutMgene database, and were considered the final NAFLD targets of metabolites from the microbiome. The results of molecular docking tests suggest that, of the 38 targets, mitogen-activated protein kinase 8-compound K and glycogen synthase kinase-3 beta-myricetin complexes might inhibit the Wnt signaling pathway. The microbiota-signaling pathways-targets-metabolites network analysis reveals that Firmicutes, Fusobacteria, the Toll-like receptor signaling pathway, mitogen-activated protein kinase 1, and phenylacetylglutamine are notable components of NAFLD and therefore to understanding its processes and possible therapeutic approaches. The key components and potential mechanisms of metabolites from gut microbiota against NAFLD were explored utilizing network pharmacology analyses. This study provides scientific evidence to support the therapeutic efficacy of metabolites for NAFLD and suggests holistic insights on which to base further research.

RGS7-ATF3-Tip60 Complex Promotes Hepatic Steatosis and Fibrosis by Directly Inducing TNFα

Aims: The pathophysiological mechanism(s) underlying non-alcoholic fatty liver disease (NAFLD) have yet to be fully delineated and only a single drug, peroxisome proliferator-activated receptor (PPAR) α/γ agonist saroglitazar, has been approved. Here, we sought to investigate the role of Regulator of G Protein Signaling 7 (RGS7) in hyperlipidemia-dependent hepatic dysfunction. Results: RGS7 is elevated in the livers of NAFLD patients, particularly those with severe hepatic damage, pronounced insulin resistance, and high inflammation. In the liver, RGS7 forms a unique complex with transcription factor ATF3 and histone acetyltransferase Tip60, which is implicated in NAFLD. The removal of domains is necessary for ATF3/Tip60 binding compromises RGS7-dependent reactive oxygen species generation and cell death. Hepatic RGS7 knockdown (KD) prevented ATF3/Tip60 induction, and it provided protection against fibrotic remodeling and inflammation in high-fat diet-fed mice translating to improvements in liver function. Hyperlipidemia-dependent oxidative stress and metabolic dysfunction were largely reversed in RGS7 KD mice. Interestingly, saroglitazar failed to prevent RGS7/ATF3 upregulation but it did partially restore Tip60 levels. RGS7 drives the release of particularly tumor necrosis factor α (TNFα) from isolated hepatocytes, stellate cells and its depletion reverses steatosis, oxidative stress by direct TNFα exposure. Conversely, RGS7 overexpression in the liver is sufficient to trigger oxidative stress in hepatocytes that can be mitigated via TNFα inhibition. Innovation: We discovered a novel non-canonical function for an R7RGS protein, which usually functions to regulate G protein coupled receptor (GPCR) signaling. This is the first demonstration for a functional role of RGS7 outside the retina and central nervous system. Conclusion: RGS7 represents a potential novel target for the amelioration of NAFLD. Antioxid. Redox Signal. 38, 137-159.

Inhibition of CBP/β-catenin signaling ameliorated fibrosis in cholestatic liver disease

Chronic cholestatic liver diseases are characterized by injury of the bile ducts and hepatocytes caused by accumulated bile acids (BAs) and inflammation. Wnt/β-catenin signaling is implicated in organ fibrosis; however, its role in cholestatic liver fibrosis remains unclear. Therefore, we explored the effect of a selective cAMP response element-binding protein-binding protein (CBP)/β-catenin inhibitor, PRI-724, on murine cholestatic liver fibrosis. PRI-724 suppressed liver fibrosis induced by multidrug resistance protein 2 knockout (KO), bile duct ligation, or a 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) diet; it also suppressed BA synthesis and macrophage infiltration. The expression of early growth response-1 (Egr-1), which plays a key role in BA synthesis, was increased in the hepatocytes of patients with cholestatic liver disease. PRI-724 inhibited Egr-1 expression induced by cholestasis, and adenoviral shEgr-1-mediated Egr-1 knockdown suppressed BA synthesis and fibrosis in DDC diet-fed mice, suggesting that PRI-724 exerts its effects, at least in part, by suppressing Egr-1 expression in hepatocytes. Hepatocyte-specific CBP KO in mice suppressed BA synthesis, liver injury, and fibrosis, whereas hepatocyte-specific KO of P300, a CBP homolog, exacerbated DDC-induced fibrosis. Intrahepatic Egr-1 expression was also decreased in hepatocyte-specific CBP-KO mice and increased in P300-KO mice, indicating that Egr-1 is located downstream of CBP/β-catenin signaling. Conclusion: PRI-724 inhibits cholestatic liver injury and fibrosis by inhibiting BA synthesis in hepatocytes. These results highlight the therapeutic effect of CBP/β-catenin inhibition in cholestatic liver diseases.

Biomarkers in Liver Disease

Symptoms and signs of liver diseases are highly variable depending on the etiology, disease stage, and type of liver involvement. There are different types of liver diseases; causes of liver diseases may be viral, toxic, metabolic, or autoimmune. However, in some cases, liver disease can develop as a result of diseases of other organs or systems. It is almost impossible to differentiate all of these solely on the basis of clinical symptoms and findings. Furthermore, the early stages of liver disease may be completely asymptomatic, or in some cases, the disease may progress with only subtle and non-specific symptoms. Therefore, biomarkers have a critical role in screening, diagnosis, staging, and evaluation of therapeutic response to treatment in liver diseases.

Liver, NAFLD and COVID-19

Coronavirus disease 2019 (COVID-19) is characterized by a wide clinical spectrum that includes abnormalities in liver function indicative of liver damage. Conversely, people with liver diseases are at higher risk of severe COVID-19. In the current review, we summarize first the epidemiologic evidence describing the bidirectional relationship between COVID-19 and liver function/liver diseases. Additionally, we present the most frequent histologic findings as well as the most important direct and indirect mechanisms supporting a COVID-19 mediated liver injury. Furthermore, we focus on the most frequent liver disease in the general population, non-alcoholic or metabolic-associated fatty liver disease (NAFLD/MAFLD), and describe how COVID-19 may affect NAFLD/MAFLD development and progression and conversely how NAFLD/MAFLD may further aggravate a COVID-19 infection. Finally, we present the long-term consequences of the pandemic on the development and management of NAFLD.

The Polyphenolic Profile and Antioxidant Activity of Five Vegetal Extracts with Hepatoprotective Potential

Oxidative stress is among the major triggers for many important human functional disorders, which often lead to various metabolic or tissue diseases. The aim of the study is to obtain five standardized vegetal extracts (Cynarae extractum-CE, Rosmarini extractum-RE, Taraxaci extractum-TE, Cichorii extractum-CHE, and Agrimoniae extractum-AE) that contain active principles with an essential role in protecting liver cells against free radicals and quantify their antioxidant actions. The compounds of therapeutic interest from the analyzed extracts were identified and quantified using the UHPLC-HRMS/MS technique. Thus, the resulting identified compounds were 28 compounds in CE, 48 compounds in RE, 39 compounds in TE, 43 compounds in CHE, and 31 compounds in AE. These compounds belong to the class of flavonoids, isoflavones, phenolic acids and dicarboxylic acids, depsides, diterpenes, triterpenes, sesquiterpenes, proanthocyanidins, or coumarin derivatives. From the major polyphenolic compounds quantified in all the extracts analyzed by UHPLC-HRMS/MS, considerable amounts have been found for chlorogenic acid (619.8 µg/g extract for TE-2032.4 µg/g extract for AE), rutoside (105.1 µg/g extract for RE-1724.7 µg/g extract for AE), kaempferol (243 µg/g extract for CHE-2028.4 µg/g extract for CE), and for naringenin (383 µg/g extract for CHE-1375.8 µg/g extract for AE). The quantitative chemical analysis showed the highest content of total phenolic acids for AE (24.1528 ± 1.1936 g chlorogenic acid/100 g dry extract), the highest concentration of flavones for RE (6.0847 ± 0.3025 g rutoside/100 g dry extract), and the richest extract in total polyphenols with 31.7017 ± 1.2211 g tannic acid equivalent/100 g dry extract for AE. Several methods (DPPH, ABTS, and FRAP) have been used to determine the in vitro total antioxidant activity of the extracts to evaluate their free radical scavenging ability, influenced by the identified compounds. As a result, the correlation between the content of the polyphenolic compounds and the antioxidant effect of the extracts has been demonstrated. Statistically significant differences were found when comparing the antiradical capacity within the study groups. Although all the analyzed extracts showed good IC50 values, which may explain their antihepatotoxic effects, the highest antioxidant activity was obtained for Agrimoniae extractum (IC50ABTS = 0.0147 mg/mL) and the lowest antioxidant activity was obtained for Cynarae extractum (IC50ABTS = 0.1588 mg/mL). Furthermore, the hepatoprotective potential was evaluated in silico by predicting the interactions between the determined phytochemicals and key molecular targets relevant to liver disease pathophysiology. Finally, the evaluation of the pharmacognostic and phytochemical properties of the studied extracts validates their use as adjuvants in phytotherapy, as they reduce oxidative stress and toxin accumulation and thus exert a hepatoprotective effect at the cellular level.

The hepatoprotective effects of plant-based foods based on the "gut-liver axis": a prospective review

The importance of the "gut-liver axis" in the pathogenesis of liver diseases has been revealed recently; which promotes the process of developing preventive and therapeutic strategies. However, considering that there are still many challenges in the medical treatment of liver diseases, potential preventive dietary intervention may be a good alternative choice. Plant-based foods have received much attention due to their reported health-promoting effects in targeting multiple pathways involved in the pathogenesis of liver diseases as well as the relative safety for general use. Based on the PubMed and Web of Science databases, this review emphatically summarizes the plant-based foods and their chemical constituents with reported effects to impact the LPS/TLR4 signaling pathway of gut-liver axis of various liver diseases, reflecting their health benefits in preventing/alleviating liver diseases. Moreover, some plant-based foods with potential gut-liver effects are specifically analyzed from the reported studies and conclusions. This review intends to provide readers an overview of the current progress in the field of this research topic. We expect to see more hepatoprotective measures for alleviating the current prevalence of liver diseases.

Molecular Mechanisms and Potential New Therapeutic Drugs for Liver Fibrosis

Liver fibrosis is the pathological process of excessive extracellular matrix deposition after liver injury and is a precursor to cirrhosis, hepatocellular carcinoma (HCC). It is essentially a wound healing response to liver tissue damage. Numerous studies have shown that hepatic stellate cells play a critical role in this process, with various cells, cytokines, and signaling pathways engaged. Currently, the treatment targeting etiology is considered the most effective measure to prevent and treat liver fibrosis, but reversal fibrosis by elimination of the causative agent often occurs too slowly or too rarely to avoid life-threatening complications, especially in advanced fibrosis. Liver transplantation is the only treatment option in the end-stage, leaving us with an urgent need for new therapies. An in-depth understanding of the mechanisms of liver fibrosis could identify new targets for the treatment. Most of the drugs targeting critical cells and cytokines in the pathogenesis of liver fibrosis are still in pre-clinical trials and there are hardly any definitive anti-fibrotic chemical or biological drugs available for clinical use. In this review, we will summarize the pathogenesis of liver fibrosis, focusing on the role of key cells, associated mechanisms, and signaling pathways, and summarize various therapeutic measures or drugs that have been trialed in clinical practice or are in the research stage.

Effectiveness of Mesenchymal Stem Cells and Bovine Colostrum on Decreasing Tumor Necrosis Factor-Α Levels and Enhancement of Macrophages M2 in Remnant Liver

BACKGROUND: Mesenchymal stem cells (MSCs) and bovine colostrum are potential therapies for the treatment of various degenerative and immune diseases. AIM: This study aimed to analyze the effect of MSCs on levels of tumor necrosis factor-Α (TNF-α) and macrophages M2 in the liver fibrosis of Wistar rats after 50% resection. METHODS: This study is a quasi-experimental post-test-only control group design to analyze the effect of giving bovine colostrum and MSCs to test animals on the process of regeneration of the remaining 50% liver with fibrosis. The study was conducted at the Stem Cell and Cancer Research Universitas Sultan Agung. The number of samples used was 40 male Wistar rats. The independent variables included MSC 1.000.0000 cells and bovine colostrum at a dose of 15 μL/g. Dependent variables used were macrophages M2 and levels of TNF-α ELISA. RESULTS: TNF-α levels on day 3 were (p = 0.001), day 7 were (p = 0.01), and day 10 were (p = 0.01) in liver tissue in various study groups analyzed using ELISA on day three*. The results showed differences which were significant between the control and treatment groups (p < 0.05). The expression of CD163 marked brown in liver tissue had more expression than the control group. CONCLUSION: The combination of MSCs and bovine colostrum can reduce TNF-α levels and significantly increase macrophages expression in the liver fibrosis of Wistar rats after 50% resection on the 3th, 7th, and 10th days.

Cellular and Molecular Mechanisms Underlying Liver Fibrosis Regression

Chronic liver injury of different etiologies may result in hepatic fibrosis, a scar formation process consisting in altered deposition of extracellular matrix. Progression of fibrosis can lead to impaired liver architecture and function, resulting in cirrhosis and organ failure. Although fibrosis was previous thought to be an irreversible process, recent evidence convincingly demonstrated resolution of fibrosis in different organs when the cause of injury is removed. In the liver, due to its high regenerative ability, the extent of fibrosis regression and reversion to normal architecture is higher than in other tissues, even in advanced disease. The mechanisms of liver fibrosis resolution can be recapitulated in the following main points: removal of injurious factors causing chronic hepatic damage, elimination, or inactivation of myofibroblasts (through various cell fates, including apoptosis, senescence, and reprogramming), inactivation of inflammatory response and induction of anti-inflammatory/restorative pathways, and degradation of extracellular matrix. In this review, we will discuss the major cellular and molecular mechanisms underlying the regression of fibrosis/cirrhosis and the potential therapeutic approaches aimed at reversing the fibrogenic process.

Cluster of Differentiation 44 Promotes Liver Fibrosis and Serves as a Biomarker in Congestive Hepatopathy

Congestive hepatopathy (CH) with chronic passive congestion is characterized by the progression of liver fibrosis without prominent inflammation and hepatocellular damage. Currently, the lack of reliable biomarkers for liver fibrosis in CH often precludes the clinical management of patients with CH. To explore fibrosis biomarkers, we performed proteome analysis on serum exosomes isolated from patients with CH after the Fontan procedure. Exosomal cluster of differentiation (CD)44 levels were increased in patients with CH compared to healthy volunteers and was accompanied by increases in serum levels of soluble CD44 and CD44 expression in the liver. To address the roles of CD44 in CH, we established a mouse model of chronic liver congestion by partial inferior vena cava ligation (pIVCL) that mimics CH by fibrosis progression with less inflammation and cellular damage. In the pIVCL mice, enhanced CD44 expression in hepatic stellate cells (HSCs) and deposition of its ligand hyaluronan were observed in the liver. Blood levels of soluble CD44 were correlated with liver fibrosis. The blockade of CD44 with specific antibody inhibited liver fibrosis in pIVCL mice and was accompanied by a reduction in S100 calcium-binding protein A4 expression following activation of HSCs. Conclusion: Chronic liver congestion promotes fibrosis through CD44. This identifies CD44 as a novel biomarker and therapeutic target of liver fibrosis in patients with CH.

Treatment with sera from Water Polo athletes activates AMPKα and ACC proteins In HepG2 hepatoma cell line

Purpose

Physical activity and professional physical activity such as water polo (WP) sport, has numerous beneficial effects to fight metabolism-related disorders through several mechanisms, including the promotion of liver metabolic adaptations, and the modulation of cytokine production. The aim of this study was to investigate the effects of different types of physical activity on AMPKα and ACC, two proteins involved in liver metabolism; therefore, we treated the hepatoma cell line Hep G2 with sera from elite WP athletes and amateur (basket) players. As control, we used serum from both sedentary and obese subjects.

Methods

Help G2 cells were treated with 5% of human sera from the different subjects; after 24 h and 48 h, HepG2 cell viability was verified through MTT assay and activation status of AMPKα and ACC through western blotting. Cytokine’s serum levels were measured through ELISA assay.

Results

After 72 h, the treatment of HepG2 cells with sera from the different subjects produced no effect on cell viability. Furthermore, after 48 h of treatment, both AMPKα and ACC phosphorylation statistically increases in HepG2 cells treated with sera from WP athletes. Furthermore, IL-4, IL-6 and IL-10 levels resulted statistically increased in WP athlete’s sera than in sedentary subjects.

Conclusion

The specific activation of AMPKα and ACC by WP sera confirms that professional sport activity carried out by WP athletes can be considered as a physiological activator of these two proteins also in HepG2 liver cells. In addition, the increase of anti-inflammatory cytokines in WP sera confirms the ample evidence for multiple anti-inflammatory activities carried out by WP discipline.

Comparative immuno-modulatory effects of basil and sesame seed oils against diazinon-induced toxicity in rats; a focus on TNF-α immunolocalization

Diazinon (DZN), a common organophosphorus insecticide (OPI), has hazardous effect to human and animals with its ubiquitous use. Considering the implication of reactive oxygen species (ROS) in the OPIs toxicity, the present study was aimed to evaluate the ameliorative properties of basil (BO) and sesame (SO) seed oils against the toxic effect of DZN. Forty adult male albino rats were divided into four experimental groups (n = 10 rats/group); control, DZN (10 mg/kg b.w/day), DZN + BO (5 ml/kg b.w/day), and DZN + SO (8 ml/kg b.w/day) groups, treated for a period of 4 weeks. DZN-exposed animals showed significant elevation in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) with a significant decline in testosterone level compared with control. On the other hand, DZN + BO and DZN + SO groups revealed significant decreases in ALT, AST, BUN, and Cr with a significant increase in testosterone level when compared with DZN-exposed animals. Oxidative/antioxidant indices revealed significant increases of malondialdehyde (MDA) levels along with significant decreases of superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT) activities among DZN-treated rats compared with control. Distinctly lower levels of MDA and increased activities of SOD, Gpx, and CAT were evident in both DZN + BO and DZN + SO groups when compared with DZN-exposed animals. Inflammatory and immuno-modulatory markers assessment showed a significant increase in TNF-α with a significant decline in IL-10 level in DZN group; meanwhile, both DZN + BO and DZN + SO groups revealed significant declines in levels of TNF-α with significant increases in IL-10. Corresponds immunohistochemistry, the total scores (TS) of TNF-α immunostainings in hepatorenal, testicular, and epididymal tissues of control, DZN + BO and DZN + SO groups were significantly lower than those values of DZN group. Additionally, the examined tissues of DZN + BO group revealed significant lower TS of TNF-α immunostaining compared with DZN + SO group. The overall data suggested that both BO and SO can be efficiently used as preventive herbal compounds against DZN-induced oxidative stress with special reference to their possible antioxidant, anti-inflammatory, and free radical activities. However, BO has more potent protective effect against DZN-induced tissue injury at both immunohistochemical and molecular levels.

Liver Fibrosis: Mechanistic Concepts and Therapeutic Perspectives

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. Correlating with liver disease progression, fibrosis is a key factor for liver disease outcome and risk of hepatocellular carcinoma (HCC). Despite different mechanism of primary liver injury and disease-specific cell responses, the progression of fibrotic liver disease follows shared patterns across the main liver disease etiologies. Scientific discoveries within the last decade have transformed the understanding of the mechanisms of liver fibrosis. Removal or elimination of the causative agent such as control or cure of viral infection has shown that liver fibrosis is reversible. However, reversal often occurs too slowly or too infrequent to avoid life-threatening complications particularly in advanced fibrosis. Thus, there is a huge unmet medical need for anti-fibrotic therapies to prevent liver disease progression and HCC development. However, while many anti-fibrotic candidate agents have shown robust effects in experimental animal models, their anti-fibrotic effects in clinical trials have been limited or absent. Thus, no approved therapy exists for liver fibrosis. In this review we summarize cellular drivers and molecular mechanisms of fibrogenesis in chronic liver diseases and discuss their impact for the development of urgently needed anti-fibrotic therapies.

A Novel Hepatic Anti-Fibrotic Strategy Utilizing the Secretome Released from Etanercept-Synthesizing Adipose-Derived Stem Cells

Tumor necrosis factor-α (TNF-α)-driven inflammatory reaction plays a crucial role in the initiation of liver fibrosis. We herein attempted to design genetically engineered adipose-derived stem cells (ASCs) producing etanercept (a potent TNF-α inhibitor), and to determine the anti-fibrotic potential of the secretome released from the etanercept-synthesizing ASCs (etanercept-secretome). First, we generated the etanercept-synthesizing ASCs by transfecting the ASCs with mini-circle plasmids containing the gene insert encoding for etanercept. We subsequently collected the secretory material released from the etanercept-synthesizing ASCs and determined its anti-fibrotic effects both in vitro (in thioacetamide [TAA]-treated AML12 and LX2 cells) and in vivo (in TAA-treated mice) models of liver fibrosis. We observed that while etanercept-secretome increased the viability of the TAA-treated AML12 hepatocytes (p = 0.021), it significantly decreased the viability of the TAA-treated LX2 HSCs (p = 0.021). In the liver of mice with liver fibrosis, intravenous administration of the etanercept-secretome induced significant reduction in the expression of both fibrosis-related and inflammation-related markers compared to the control group (all Ps < 0.05). The etanercept-secretome group also showed significantly lower serum levels of liver enzymes as well as pro-inflammatory cytokines, such as TNF-α (p = 0.020) and IL-6 (p = 0.021). Histological examination of the liver showed the highest reduction in the degree of fibrosis in the entanercept-secretome group (p = 0.006). Our results suggest that the administration of etanercept-secretome improves liver fibrosis by inhibiting TNF-α-driven inflammation in the mice with liver fibrosis. Thus, blocking TNF-α-driven inflammation at the appropriate stage of liver fibrosis could be an efficient strategy to prevent fibrosis.

Bouchardatine analogue alleviates non-alcoholic hepatic fatty liver disease/non-alcoholic steatohepatitis in high-fat fed mice by inhibiting ATP synthase activity

BACKGROUND AND PURPOSE

Non-alcoholic hepatic fatty liver disease (NAFLD) is a manifestation of the metabolic syndrome in the liver and non-alcoholic steatohepatitis (NASH) represents its advanced stage. R17 derived from bouchardatine, shows benefits in the metabolic syndrome, but has not been tested in the liver. The present study examined the pharmacological effects of R17 in a model of NAFLD/NASH and its mode of action.

EXPERIMENTAL APPROACH

The effects of R17 were examined in mice fed a high-fat (HF) diet to induce the pathological characteristics of NAFLD/NASH and in cultures of HuH7 cells. We used histological and immunohistochemical techniques along with western blotting and siRNA. Generation of ROS and apoptosis were measured.

KEY RESULTS

Administration of R17 (20 mg·kg^-1 , i.p. every other day) for 5 weeks reversed HF-induced hepatic triglyceride content, inflammation (inflammatory cytokines and macrophage numbers), injury (hepatocyte ballooning and apoptosis, plasma levels of alanine aminotransferase and aspartate aminotransferase), and fibrogenesis (collagen deposition and mRNA expression of fibrosis markers). In cultured cells, R17 reduced cell steatosis from both lipogenesis and fatty acid influx. The attenuated inflammation and cell injury were associated with inhibition of both endoplasmic reticulum (ER) stress and oxidative stress. Notably, R17 activated the liver kinase B1-AMP-activated protein kinase (AMPK) pathway by inhibiting activity of ATP synthase, rather than direct stimulation of AMPK.

CONCLUSION AND IMPLICATIONS

R17 has therapeutic potential for NAFLD/NASH. Its mode of action involves the elimination of ER and oxidative stresses, possibly via activating the LKB1-AMPK axis by inhibiting the activity of ATP synthase.

Chemical induction of hepatic apoptosis in rodents

The urge of identifying new pharmacological interventions to prevent or attenuate liver injury is of critical importance and needs an expanded experimental toolbox. Hepatocyte injury and cellular death is a prominent feature behind the pathology of liver diseases. Several research activities focused on identifying chemicals and hepatotoxicants that induce cell death by apoptosis, in addition to presenting its corresponding signaling pathway. Although such efforts provided further understanding of the mechanisms of cell death, it has also raised confusion concerning identifying the involvement of several modes of cell death including apoptosis, necrosis and fibrosis. The current review highlights the ability of several chemicals and potential hepatotoxicants to induce liver damage in rodents by means of apoptosis while the probable involvement of other modes of cell death is also exposed. Thus, several chemical substances including hepatotoxins, mycotoxins, hyperglycemia inducers, metallic nanoparticles and immunosuppressant drugs are reviewed to explore the hepatic cytotoxic spectrum they could exert on hepatocytes of rodents. In addition, the current review address the mechanism by which hepatotoxicity is initiated in hepatocytes in different rodents aiding the researcher in choosing the right animal model for a better research outcome.

Wnt/β-Catenin Signaling as a Potential Target for the Treatment of Liver Cirrhosis Using Antifibrotic Drugs

Cirrhosis is a form of liver fibrosis resulting from chronic hepatitis and caused by various liver diseases, including viral hepatitis, alcoholic liver damage, nonalcoholic steatohepatitis, and autoimmune liver disease. Cirrhosis leads to various complications, resulting in poor prognoses; therefore, it is important to develop novel antifibrotic therapies to counter liver cirrhosis. Wnt/β-catenin signaling is associated with the development of tissue fibrosis, making it a major therapeutic target for treating liver fibrosis. In this review, we present recent insights into the correlation between Wnt/β-catenin signaling and liver fibrosis and discuss the antifibrotic effects of the cAMP-response element binding protein/β-catenin inhibitor PRI-724.