Oxidative mechanisms in the pathogenesis of alcoholic liver disease

Cysteine triggered cascade reaction forming coumarin: Visualization of cysteine fluctuation in alcoholic liver disease by a NIR fluorescent probe

Alcoholic liver disease (ALD) is a chronic toxic liver injury caused by long-term heavy drinking. Due to the increasing incidence, ALD is becoming one of important medical tasks. Many studies have shown that the main mechanism of liver damage caused by large amounts of alcohol may be related to antioxidant stress. As an important antioxidant, cysteine (Cys) is involved in maintaining the normal redox balance and detoxifying metabolic function of the liver, which may be closely related to the pathogenesis of ALD. Therefore, it is necessary to develop a simple non-invasive method for rapid monitoring of Cys in liver. Thus, a near-infrared (NIR) fluorescent probe DCI-Ac-Cys which undergoes Cys triggered cascade reaction to form coumarin fluorophore is developed. Using the DCI-Ac-Cys, decreased Cys was observed in the liver of ALD mice. Importantly, different levels of Cys were monitored in the livers of ALD mice taking silybin and curcumin with the antioxidant effects, indicating the excellent therapeutic effect on ALD. This study provides the important references for the accurate diagnosis of ALD and the pharmacodynamic evaluation of silybin and curcumin in the treatment of ALD, and support new ideas for the pathogenesis of ALD.

A new opportunity for N-acetylcysteine. An outline of its classic antioxidant effects and its pharmacological potential as an epigenetic modulator in liver diseases treatment

Liver diseases represent a worldwide health problem accountable for two million deaths per year. Oxidative stress is critical for the development of these diseases. N-acetyl cysteine (NAC) is effective in preventing liver damage, both in experimental and clinical studies, and evidence has shown that the pharmacodynamic mechanisms of NAC are related to its antioxidant nature and ability to modulate key signaling pathways. Here, we provide a comprehensive description of the beneficial effects of NAC in the treatment of liver diseases, addressing the first evidence of its role as a scavenger and precursor of reduced glutathione, along with studies showing its immunomodulatory action, as well as the ability of NAC to modulate epigenetic hallmarks. We searched the PubMed database using the following keywords: oxidative stress, liver disease, epigenetics, antioxidants, NAC, and antioxidant therapies. There was no time limit to gather all available information on the subject. NAC has shown efficacy in treating liver damage, exerting mechanisms of action different from those of free radical scavengers. Like different antioxidant therapies, its effectiveness and safety are related to the administered dose; therefore, designing new pharmacological formulations for this drug is imperative to achieve an adequate response. Finally, there is still much to explore regarding its effect on epigenetic marker characteristics of liver damage, turning it into a drug with broad therapeutic potential. According to the literature reviewed, NAC could be an appropriate option in clinical studies related to hepatic injury and, in the future, a repurposing alternative for treating liver diseases.

Mitochondria and Alcohol-Associated Liver Disease: Pathogenic Role and Target for Therapy

Alcohol-associated liver disease (ALD) is one of the leading causes of chronic liver disease and a major cause of liver-related death. ALD is a multifactorial disease triggered by the oxidative metabolism of alcohol which leads to the activation of multiple factors that promote the progression from steatosis to more advanced stages like alcohol-associated steatohepatitis (AH) that culminate in alcohol-associated cirrhosis and hepatocellular carcinoma. Poor understanding of the complex heterogeneous pathology of ALD has limited drug development for this disease. Alterations in mitochondrial performance are considered a crucial event in paving the progression of ALD due to the crucial role of mitochondria in energy production, intermediate metabolism, calcium homeostasis, and cell fate decisions. Therefore, understanding the role of mitochondria in eliciting steatosis and progression toward AH may open the door to new opportunities for treatment. In this review, we will cover the physiological function of mitochondria, its contribution to ALD in experimental models and human disease, and explore whether targeting mitochondria may represent a game changer in the treatment of ALD.

Consumption of Sylimarin, Pyrroloquinoline Quinone Sodium Salt and Myricetin: Effects on Alcohol Levels and Markers of Oxidative Stress-A Pilot Study

BACKGROUND

Alcohol abuse is one of the most common causes of mortality worldwide. This study aimed to investigate the efficacy of a treatment in reducing circulating ethanol and oxidative stress biomarkers.

METHODS

Twenty wine-drinking subjects were investigated in a randomized controlled, single-blind trial (ClinicalTrials.gov. Identifier: NCT06548503; Ethical Committee of the University of Padova (HEC-DSB/12-2023) to evaluate the effect of the intake of a product containing silymarin, pyrroloquinoline quinone sodium salt, and myricetin (referred to as Si.Pi.Mi. for this project) on blood alcohol, ethyl glucuronide (EtG: marker for alcohol consumption) and markers of oxidative stress levels (Reactive Oxygen Species-ROS, Total Antioxidant Capacity-TAC, CoQ10, thiols redox status, 8-isoprostane, NO metabolites, neopterin, and uric acid). The effects of the treatment versus placebo were evaluated acutely and after 1 week of supplementation in blood and/or saliva and urine samples.

RESULTS

Si.Pi.Mi intake reduced circulating ethanol after 120 min (-33%). Changes in oxidative stress biomarkers, particularly a TAC (range +9-12%) increase and an 8-isoprostane (marker of lipidic peroxidation) decrease (range -22-27%), were observed too.

CONCLUSION

After the administration of Si.Pi.Mi, the data seemed to suggest a better alcohol metabolism and oxidative balance in response to wine intake. Further verification is requested.

Hovenia dulcis: a Chinese medicine that plays an essential role in alcohol-associated liver disease

Globally, alcohol-associated liver disease (ALD) has become an increased burden for society. Disulfirams, Benzodiazepines (BZDs), and corticosteroids are commonly used to treat ALD. However, the occurrence of side effects such as hepatotoxicity and dependence, impedes the achievement of desirable and optimal therapeutic efficacy. Therefore, there is an urgent need for more effective and safer treatments. Hovenia dulcis is an herbal medicine promoting alcohol removal clearance, lipid-lowering, anti-inflammatory, and hepatoprotective properties. Hovenia dulcis has a variety of chemical components such as dihydromyricetin, quercetin and beta-sitosterol, which can affect ALD through multiple pathways, including ethanol metabolism, immune response, hepatic fibrosis, oxidative stress, autophagy, lipid metabolism, and intestinal barrier, suggesting its promising role in the treatment of ALD. Thus, this work aims to comprehensively review the chemical composition of Hovenia dulcis and the molecular mechanisms involved in the process of ALD treatment.

Clinical efficacy of probiotics in the treatment of alcoholic liver disease: a systematic review and meta-analysis

Objective

Alcoholic liver disease (ALD) is a liver damage disease caused by long-term heavy drinking. Currently, there is no targeted pharmaceutical intervention available for the treatment of this disease. To address this, this paper evaluates the efficacy and safety of probiotic preparation in treating ALD through conducting a meta-analysis, and provides a valuable insight for clinical decision-making.

Methods

A systematic search was conducted across databases, including PubMed, Embase, Web of Science, Cochrane Library, CNKI, VIP, Wanfang, and CBM from the inception dates to October 15, 2023, to identify clinical randomized controlled trials on probiotic preparations in the treatment of ALD. After the literature underwent screening, data extraction, and quality assessment, RevMan 5.3 and Stata 14.2 were employed for data analysis and processing.

Results

A total of 9 randomized controlled trials fulfilled the inclusion criteria. The results of the meta-analysis showed that probiotic preparation could significantly improve the liver function of patients with alcoholic liver disease compared with the control group. Probiotic intervention led to a significant reduction in the levels of alanine aminotransferase (MD=-13.36,95%CI:-15.80,-10.91;P<0.00001),aspartate aminotransferase (MD=-16.99,95%CI:-20.38,-13.59;P<0.00001),γ-glutamyl transpeptidase (MD=-18.79,95% CI:-28.23,-9.34; P<0.0001). Concurrently, the level of serum albumin (MD=0.19,95% CI:0.02,0.36;P=0.03) was increased. Furthermore, probiotic intervention could also modulate the composition of intestinal flora in patients with alcoholic liver disease, leading to an augmentation in Bifidobacteria and a reduction in Escherichia coli. However, in patients with alcoholic liver disease, probiotic intervention showed no significant effects on total bilirubin (MD=-0.01,95% CI:-0.17,0.15;P=0.91), tumor necrosis factor-α (MD=0.03,95% CI:-0.86,0.92;P=0.94) and interleukin-6 (MD=-5.3,95% CI:-16.04,5.45;P=0.33).

Conclusion

The meta-analysis indicates that probiotics can improve liver function in alcoholic liver disease, reduce inflammatory responses, regulate intestinal flora, which have potential value in the treatment of alcoholic liver disease.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023472527.

Acetyl-L-carnitine attenuates chronic ethanol-induced oxidative stress, ER stress and apoptosis in rat gastric tissue

Consuming alcohol affects almost all organs. Acetaldehyde, formed as the main product as a result of alcohol metabolism, causes the production of free superoxide radicals when oxidized, and accordingly oxidative and apoptotic processes are triggered. There are studies showing that carnitine has effects on oxidative and apoptotic processes that occur in various conditions. However, the mechanisms showing the effects of L-carnitine on these effects of alcohol have not been fully elucidated. In our study, the effects of acetyl-L-carnitine administration on the molecular mechanisms of oxidative stress, endoplasmic reticulum stress, and apoptotic parameters in gastric tissue of rats chronically exposed to alcohol were investigated. Hematoxylin-eosin staining was used for histopathological studies. Endoplasmic reticulum stress markers were detected with immunohistochemical staining and western blotting. Apoptotic index was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Total oxidant and antioxidant status were examined by ELISA. Our results showed that chronic alcohol administration caused a significant increase in TOS levels, an indicator of oxidative stress, the levels of ER-stress-associated proteins XBP1, GRP78, and CHOP, and % apoptotic index values in rat gastric tissues. Additionally, it was determined that acetyl-L-carnitine administration caused an improvement in those values. Based on our data, we can conclude that acetyl-L-carnitine has a tissue protective effect by scavenging free oxygen radicals and reducing ER stress-related proteins XBP1, GRP78, and CHOP and apoptosis in chronic ethanol-administered rats, and that this natural antioxidant may be beneficial in the treatment of oxidative stress-induced diseases.

CD73 mitigates hepatic damage in alcoholic steatohepatitis by regulating PI3K/AKT-mediated hepatocyte pyroptosis

BACKGROUND

Alcohol use is a major risk factor for death and disability, resulting in a significant global disease burden. Alcoholic steatohepatitis (ASH) reflects an acute exacerbation of alcoholic liver disease (ALD) and is a growing health care and economic burden worldwide. Pyroptosis plays a central role in the pathogenesis of ASH. Nt5e (CD73) is a cell surface ecto-5'-nucleotidase, which is a key enzyme that converts the proinflammatory signal ATP to the anti-inflammatory mediator adenosine (ADO). Studies have found that CD73 is involved in multiple diseases and can alleviate gasdermin D (GSDMD)-mediated pyroptosis; however, its role and mechanism in ASH are not explicit.

AIM

To investigate the role and mechanisms of CD73-mediated hepatocyte pyroptosis in alcohol-induced liver injury through in vivo and in vitro experiments.

METHODS

CD73 knockout (CD73-/-) mice, wild-type (WT) mice, and AML-12 cells were used to evaluate the effect of CD73 on hepatocyte pyroptosis in vivo and in vitro. A combination of molecular and histological methods was performed to assess pyroptosis and investigate the mechanism both in vivo and in vitro.

RESULTS

The protein expression of CD73 and pyroptosis pathway-associated genes was increased significantly in hepatocyte injury model both in vivo and in vitro. In vivo, CD73 knockout dramatically aggravated inflammatory damage, lipid accumulation, and hepatocyte pyroptosis in the liver. In vitro, overexpression of CD73 by pEGFP-C1/CD73 can decrease NLRP3 inflammasome activation and pyroptosis in hepatocytes. Further analysis revealed that the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is a possible mechanism of CD73 regulation. Meanwhile, this pathological process was inhibited after the use of PI3K inhibitors.

CONCLUSION

Our results show a novel function of CD73 regulates hepatocytes pyroptosis and highlights the therapeutic opportunity for reducing the disease process in ALD.

Experimental Models for Studying Structural and Functional State of the Pathological Liver (Review)

Liver pathologies remain one of the leading causes of mortality worldwide. Despite a high prevalence of liver diseases, the possibilities of diagnosing, prognosing, and treating non-alcoholic and alcoholic liver diseases still have a number of limitations and require the development of new methods and approaches. In laboratory studies, various models are used to reconstitute the pathological conditions of the liver, including cell cultures, spheroids, organoids, microfluidic systems, tissue slices. We reviewed the most commonly used in vivo, in vitro, and ex vivo models for studying non-alcoholic fatty liver disease and alcoholic liver disease, toxic liver injury, and fibrosis, described their advantages, limitations, and prospects for use. Great emphasis was placed on the mechanisms of development of pathological conditions in each model, as well as the assessment of the possibility of reconstructing various key aspects of pathogenesis for all these pathologies. There is currently no consensus on the choice of the most adequate model for studying liver pathology. The choice of a certain effective research model is determined by the specific purpose and objectives of the experiment.

Autophagy, Oxidative Stress, and Alcoholic Liver Disease: A Systematic Review and Potential Clinical Applications

Ethanol consumption triggers oxidative stress by generating reactive oxygen species (ROS) through its metabolites. This process leads to steatosis and liver inflammation, which are critical for the development of alcoholic liver disease (ALD). Autophagy is a regulated dynamic process that sequesters damaged and excess cytoplasmic organelles for lysosomal degradation and may counteract the harmful effects of ROS-induced oxidative stress. These effects include hepatotoxicity, mitochondrial damage, steatosis, endoplasmic reticulum stress, inflammation, and iron overload. In liver diseases, particularly ALD, macroautophagy has been implicated as a protective mechanism in hepatocytes, although it does not appear to play the same role in stellate cells. Beyond the liver, autophagy may also mitigate the harmful effects of alcohol on other organs, thereby providing an additional layer of protection against ALD. This protective potential is further supported by studies showing that drugs that interact with autophagy, such as rapamycin, can prevent ALD development in animal models. This systematic review presents a comprehensive analysis of the literature, focusing on the role of autophagy in oxidative stress regulation, its involvement in organ-organ crosstalk relevant to ALD, and the potential of autophagy-targeting therapeutic strategies.

System Biology Investigation Revealed Lipopolysaccharide and Alcohol-Induced Hepatocellular Carcinoma Resembled Hepatitis B Virus Immunobiology and Pathogenesis

Hepatitis B infection caused by the hepatitis B virus is a life-threatening cause of liver fibrosis, cirrhosis, and hepatocellular carcinoma. Researchers have produced multiple in vivo models for hepatitis B virus (HBV) and, currently, there are no specific laboratory animal models available to study HBV pathogenesis or immune response; nonetheless, their limitations prevent them from being used to study HBV pathogenesis, immune response, or therapeutic methods because HBV can only infect humans and chimpanzees. The current study is the first of its kind to identify a suitable chemically induced liver cirrhosis/HCC model that parallels HBV pathophysiology. Initially, data from the peer-reviewed literature and the GeneCards database were compiled to identify the genes that HBV and seven drugs (acetaminophen, isoniazid, alcohol, D-galactosamine, lipopolysaccharide, thioacetamide, and rifampicin) regulate. Functional enrichment analysis was performed in the STRING server. The network HBV/Chemical, genes, and pathways were constructed by Cytoscape 3.6.1. About 1546 genes were modulated by HBV, of which 25.2% and 17.6% of the genes were common for alcohol and lipopolysaccharide-induced hepatitis. In accordance with the enrichment analysis, HBV activates the signaling pathways for apoptosis, cell cycle, PI3K-Akt, TNF, JAK-STAT, MAPK, chemokines, NF-kappa B, and TGF-beta. In addition, alcohol and lipopolysaccharide significantly activated these pathways more than other chemicals, with higher gene counts and lower FDR scores. In conclusion, alcohol-induced hepatitis could be a suitable model to study chronic HBV infection and lipopolysaccharide-induced hepatitis for an acute inflammatory response to HBV.

Antioxidant effects of Se-glutathione peroxidase in alcoholic liver disease

Oxidative damage induced by ethanol and its metabolites is one of the factors that fuels the development of alcoholic liver disease (ALD). Selenium (Se) is an effective cofactor for glutathione peroxidase (GPx), and has antioxidant effects that improve ALD. In patients with ALD, ethanol-induced oxidative damage inhibits the synthesis of related Se-containing proteins such as: selenoprotein P (Sepp1), albumin (ALB), and GPx in the liver, thus decreasing the overall Se level in patients. Both Se deficiency and excess can affect the expression of GPx, resulting in damage to the antioxidant defense system. This damage enhances oxidative stress by increasing the levels of reactive oxygen species (ROS) in the body, which aggravates the inflammatory response, lipid metabolism disorder, and lipid peroxidation and worsens ALD symptoms. A cascade of oxidative damages caused by ALD will deplete selenium deposition in the body, stimulate the expression of Gpx1, Sepp1, and Gpx4, and thus mobilize systemic selenoproteins, which can restore GPx activity in the hepatocytes of ALD patients, reduce the levels of reactive oxygen species and alleviate oxidative stress, the inflammatory response, lipid metabolism disorder, and lipid peroxidation, thus helping to mitigate ALD. This review provides a reference for future ALD studies that evaluate the regulation of Se levels and contributes to studies on the potential pathological mechanisms of Se imbalance in ALD.

Preparation and Hepatoprotective Activities of Peptides Derived from Mussels (Mytilus edulis) and Clams (Ruditapes philippinarum)

Low molecular weight (<5 kDa) peptides from mussels (Mytilus edulis) (MPs) and the peptides from clams (Ruditapes philippinarum) (CPs) were prepared through enzymatic hydrolysis by proteases (dispase, pepsin, trypsin, alcalase and papain). Both the MPs and the CPs showed excellent in vitro scavenging ability of free radicals including OH, DPPH and ABTS in the concentration range of 0.625−10.000 mg/mL. By contrast, the MPs hydrolyzed by alcalase (MPs-A) and the CPs hydrolyzed by dispase (CPs-D) had the highest antioxidant activities. Furthermore, MPs-A and CPs-D exhibited protective capabilities against oxidative damage induced by H2O2 in HepG2 cells in the concentration range of 25−800 μg/mL. Meanwhile, compared with the corresponding indicators of the negative control (alcohol-fed) mice, lower contents of hepatic MDA and serums ALT and AST, as well as higher activities of hepatic SOD and GSH-PX were observed in experiment mice treated with MPs-A and CPs-D. The present results clearly indicated that Mytilus edulis and Ruditapes philippinarum are good sources of hepatoprotective peptides.

The effect of Lactobacillus rhamnosus B10 on alcoholic liver injury and intestinal microbiota in alcohol-induced mice model

Lactobacillus rhamnosus B10 (L. rhamnosus B10) isolated from the baby feces was given to an alcohol mice model, aiming to investigate the effects of L. rhamnosus B10 on alcoholic liver injury by regulating intestinal microbiota. C57BL/6N mice were fed with liquid diet Lieber-DeCarli with or without 5% (v/v) ethanol for 8 weeks, and treated with L. rhamnosus B10 at the last 2 weeks. The results showed that L. rhamnosus B10 decreased the serum total cholesterol (1.48 mmol/L), triglycerides (0.97 mmol/L), alanine aminotransferase (26.4 U/L), aspartate aminotransferase (14.2 U/L), lipopolysaccharide (0.23 EU/mL), and tumor necrosis factor-α (138 pg/mL). In addition, L. rhamnosus B10 also reduced the liver triglycerides (1.02 mmol/g prot), alanine aminotransferase (17.8 mmol/g prot) and aspartate aminotransferase (12.5 mmol/g prot) in alcohol mice, thereby ameliorating alcohol-induced liver injury. The changes of intestinal microbiota composition on class, family and genus level in cecum were analyzed. The intestinal symbiotic abundance of Firmicutes was elevated while gram-negative bacteria Proteobacteria and Deferribacteres was decreased in alcohol mice treated with L. rhamnosus B10 for 2 weeks. In summary, this study provided evidence for the therapeutic effects of probiotics on alcoholic liver injury by regulating intestinal flora.

Comparative Hepatotoxicity of a Novel Perfluoroalkyl Ether Sulfonic Acid, Nafion Byproduct 2 (H-PFMO2OSA), and Legacy Perfluorooctane Sulfonate (PFOS) in Adult Male Mice

Nafion byproduct 2 (H-PFMO2OSA) has been detected in the environment, but little is known about its toxicities. To compare the hepatotoxicity of H-PFMO2OSA with legacy perfluorooctane sulfonate (PFOS), male adult mice were exposed to 0.2, 1, or 5 mg/kg/d of each chemical for 28 days. Results showed that, although H-PFMO2OSA liver and serum concentrations were lower than those of PFOS, the relative liver weight in the H-PFMO2OSA groups was significantly higher than that in the corresponding PFOS groups. In addition, the increase in alanine transaminase and aspartate aminotransferase activity was greater in the H-PFMO2OSA groups than in the PFOS groups. Reduced glutathione (GSH) content and glutathione reductase activity in the liver increased in the 1 and 5 mg/kg/d H-PFMO2OSA groups and in the 5 mg/kg/d PFOS group. Liver quantitative proteome analysis demonstrated that, similar to PFOS, H-PFMO2OSA caused lipid metabolism disorder, and most lipid metabolism-related differentially expressed proteins (DEPs) were controlled by peroxisome proliferator-activated receptor alpha (PPARα). Additionally, KEGG enrichment analysis highlighted changes in the GSH metabolism pathway after PFOS and H-PFMO2OSA exposure. Then, there were eight DEPs involved in the GSH metabolism pathway that mostly were upregulated after exposure to H-PFMO2OSA but not after exposure to PFOS. In conclusion, H-PFMO2OSA induced higher levels of liver damage and more serious GSH metabolism dysregulation compared to PFOS.

The Hepatoprotective Effect of Leonurine Hydrochloride Against Alcoholic Liver Disease Based on Transcriptomic and Metabolomic Analysis

Excessive alcohol consumption can eventually progress to alcoholic liver disease (ALD). The underlying mechanism of ALD toxicity is primarily associated with oxidative damage. Many alkaloids have been reported to possess potential antioxidative efficacy, while the mechanism of their hepatoprotective activity against ALD is still not clear. In this study, eight alkaloids were selected from a monomer library of Traditional Chinese Medicine and evaluated for their antioxidant activity against ALD by the evaluation of Glutathione (GSH) and Malondialdehyde (MDA). The result suggested that Leonurine hydrochloride (LH) was a potent antioxidant that could reduce alcoholic liver damage. To further investigate the underlying mechanism of LH against ALD, the molecular pathway induced by LH was identified by RNA-seq analyses. Transcriptome data revealed the principal mechanism for the protective effect of LH against ALD might be attributed to the differentially expressed genes (DEGs) of PI3K-AKT, AMPK, and HIF-1 signaling pathways involved in the lipid metabolism. Given the hepatoprotective mechanism of LH is involved in lipid metabolism, the lipid metabolism induced by LH was further analyzed by UHPLC-MS/MS. Metabolome analysis indicated that LH significantly regulated glycerophospholipid metabolism including phosphatidylcholine, 1-acyl-sn-glycero-3-phosphocholine, phosphatidylethanolamine and 1-acyl-sn-glycero-3-phosphoethanolamine in the liver. Overall, this study revealed that the hepatoprotective mechanism of LH against alcoholic liver damage might be associated with the genes involved in glycerophospholipid metabolism.

Protective effect of luteolin against chemical and natural toxicants by targeting NF-κB pathway

Humans are continuously exposed to environmental, occupational, consumer and household products, food, and pharmaceutical substances. Luteolin, a flavone from the flavonoids family of compounds, is found in different fruits and vegetables. LUT is a strong anti-inflammatory (via inhibition of NF-κB, ERK1/2, MAPK, JNK, IL-6, IL-8, and TNF-α) and antioxidant agent (reducing ROS and enhancement of endogenous antioxidants). LUT can chelate transition metal ions responsible for ROS generation and consequently repress lipoxygenase. It has been proven that NF-κB, as a commom cellular pathway plays a considerable role in the progression of inflammatory process and stimulates the expression of genes encoding inducible pro-inflammatory enzymes (iNOS and COX-2) and cytokines including IL-1β, IL-6, and TNF-α. This review summarizes the available literature discussing LUT and its potential protective role against pharmaceuticals-, metals-, and environmental compounds-induced toxicities. Furthermore, the review explains the involved protective mechanisms, especially inhibition of the NF-κB pathway.

Lipid Peroxidation Levels in Saliva and Plasma of Patients Suffering from Periodontitis

Lipid peroxidation (LPO) participates in the development of various diseases, including periodontitis, and malondialdehyde (MDA) is its terminal product. Therefore, in the present study, salivary and plasma MDA levels in 30 periodontitis patients were compared to those in 20 healthy controls, as well as in relation to periodontal therapy in order to assess its effectiveness. Periodontal status was assessed via plaque index, gingival index, papilla bleeding index, probing depth and clinical attachment level, while salivary and plasma MDA levels were determined by the ELISA method. The periodontitis group had a significantly greater salivary (2.99 pmol/µL) and plasma (0.50 pmol/µL) MDA levels relative to the healthy controls (1.33 pmol/µL and 0.40 pmol/µL, respectively). Three months after the periodontal therapy completion, although salivary MDA levels were significantly lower than those measured at the baseline (p < 0.001), the reduction in plasma MDA was not statistically significant (p > 0.05). These findings indicate that, while inflammatory processes in periodontium may increase local and systemic lipid peroxidation, periodontal therapy can result in a significant decrease in salivary, but not plasma, MDA levels.

Insulin resistance enhances binge ethanol-induced liver injury through promoting oxidative stress and up-regulation CYP2E1

Alcoholic liver disease (ALD) has caused a serious burden on public and personal health in crowd with ethanol abuse. The effects of insulin resistance (IR) on ALD and the mechanisms underlying these responses are still not well understood. In this study, we investigated the changes of liver injury, inflammation, apoptosis, mitochondrial dysfunction and CYP2E1 changes in liver of mice exposed to ethanol with IR or not. We found IR increased the sensitivity of liver injury in mice exposed to ethanol, manifested as the increase serum activities of AST and ALT, the accumulation of triglycerides, the deterioration of liver pathology and increase of inflammatory factors. IR also exacerbated apoptosis and mitochondrial dysfunction in liver of mice exposed to ethanol. The increase of oxidative stress and the decrease of antioxidant defense ability might be responsible for the sensitizing effects of IR on ethanol-induced liver injury, supported by the increase of MDA levels and the decline of GSH/GSSG, the inactivation of antioxidant enzymes SOD, GR through the inhibition of Nrf-2 pathway. The activation of CYP2E1 might be also involved in the sensitizing effects of IR on ethanol induced liver injury in mice. These results demonstrated that IR exhibited a significant pro-oxidative and pro-apoptosis effects to aggravate alcoholic liver injury. Our study helped us to better understand the sensitive role of IR on ALD and suggested that alcohol intake may be more harmful for people with IR.

The Regulatory Roles of Polysaccharides and Ferroptosis-Related Phytochemicals in Liver Diseases

Liver disease is a global health burden with high morbidity and mortality worldwide. Liver injuries can develop into severe end-stage diseases, such as cirrhosis or hepatocellular carcinoma, without valid treatment. Therefore, identifying novel drugs may promote liver disease treatment. Phytochemicals, including polysaccharides, flavonoids, alkaloids, and terpenes, are abundant in foods and medicinal plants and have various bioactivities, such as antioxidation, immunoregulation, and tumor killing. Recent studies have shown that many natural polysaccharides play protective roles in liver disease models in vitro and in vivo, such as fatty liver disease, alcoholic liver disease, drug-induced liver injury, and liver cancer. The mechanisms of liver disease are complex. Notably, ferroptosis, a new type of cell death driven by iron and lipid peroxidation, is considered to be the key mechanism in many hepatic pathologies. Therefore, polysaccharides and other types of phytochemicals with activities in ferroptosis regulation provide novel therapeutic strategies for ferroptosis-related liver diseases. This review summarizes our current understanding of the mechanisms of ferroptosis and liver injury and compelling preclinical evidence of natural bioactive polysaccharides and phytochemicals in treating liver disease.

Roxadustat, a Hypoxia-Inducible Factor 1α Activator, Attenuates Both Long- and Short-Term Alcohol-Induced Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a worldwide healthcare problem featured by inflammation, reactive oxygen species (ROS), and lipid dysregulation. Roxadustat is used for chronic kidney disease anemia treatment. As a specific inhibitor of prolyl hydroxylase, it can maintain high levels of hypoxia-inducible factor 1α (HIF-1α), through which it can further influence many important pathways, including the three featured in ALD. However, its effects on ALD remain to be elucidated. In this study, we used chronic and acute ALD mouse models to investigate the protective effects of roxadustat in vivo. Our results showed that long- and short-term alcohol exposure caused rising activities of serum transaminases, liver lipid accumulation, and morphology changes, which were reversed by roxadustat. Roxadustat-reduced fatty liver was mainly contributed by the reducing sterol-responsive element-binding protein 1c (SREBP1c) pathway, and enhancing β-oxidation through inducing peroxisome proliferator-activated receptor α (PPARα) and carnitine palmitoyltransferase 1A (CPT1A) expression. Long-term alcohol treatment induced the infiltration of monocytes/macrophages to hepatocytes, as well as inflammatory cytokine expression, which were also blocked by roxadustat. Moreover, roxadustat attenuated alcohol caused ROS generation in the liver of those two mouse models mainly by reducing cytochrome P450 2E1 (CYP2E1) and enhancing superoxidase dismutase 1 (SOD1) expression. In vitro, we found roxadustat reduced inflammation and lipid accumulation mainly via HIF-1α regulation. Taken together, our study demonstrates that activation of HIF-1α can ameliorate ALD, which is contributed by reduced hepatic lipid synthesis, inflammation, and oxidative stress. This study suggested that roxadustat could be a potential drug for ALD treatment.

Nrf2 signalling pathway and autophagy impact on the preventive effect of green tea extract against alcohol-induced liver injury

OBJECTIVES

To explore the potential molecular mechanism underlying the effect of green tea extract (TE), rich in tea polyphenols (TPs), on improving alcohol-induced liver injury.

METHODS

Mice were intragastrically treated with 50% (v/v) alcohol administration (15 ml/kg BW) with or without three doses of TE (50, 120 and 300 mg TPs/kg BW) daily for 4 weeks, and biological changes were tested.

KEY FINDINGS

The TE improved the functional and histological situations in the liver of the mice accepted alcohol administration, including enzymes for alcohol metabolism, oxidative stress and lipid accumulation. Interestingly, the TE increased the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2), with the decreasing expression of kelch-like ECH-associated protein 1 (Keap1), indicating the association between the effect of TE with Nrf2-mediated antioxidant signalling. Moreover, the TE restored the activity of autophagy, showing as lifted Beclin-1 expression, LC3B-II/LC3B-I ratio, and decreased p62 expression. Importantly, all these effects were dose-dependent.

CONCLUSIONS

These findings provide a new notion for the first time that the TE preventing against alcohol-induced liver injury is closely related to accelerated metabolism of alcohol and relieved oxidative stress, which is associated with Nrf2 signalling activation and autophagy restoration, thus the reduction of lipid accumulation in liver.

Meta-Analysis and Systematic Review of Primary Renal Tubular Acidosis in Patients With Autoimmune Hepatitis and Alcoholic Hepatitis

Renal and hepatic functions are often mingled through both the existence of associated primary organ diseases and hemodynamic co-relationship. The primary objective of this study was to sum up the relationship between autoimmune hepatitis (AIH) on renal tubular acidosis (RTA) and the stages of the disease. A systematic review was performed for 24 trials. A total of 3687 patients were included. The incidence of RTA occurring and short-term mortality reduction was seen in two groups; for an overall effect: Z = 2.85 (P = 0.004) a total 95% CI of 0.53 [0.34, 0.82]. Only one patient with alcoholic liver cirrhosis was found to have an incomplete type of RTA. Test for overall effect: Z = 2.28 (P = 0.02) 95% CI of 2.83 [1.16, 6.95]. A reduction in fatal infections with dual therapy of corticosteroid plus N-acetylcysteine (NAC) test for overall effect: Z = 3.07 (P = 0.002) with 95% CI of 0.45 [0.27, 0.75]. Autoimmune diseases are the most frequent underlying cause of secondary RTA in adults. The primary renal disease must be actively excluded in all patients with hepatic failure by aggressive clinical and laboratory evaluations.

Effect of Lactobacillus casei on lipid metabolism and intestinal microflora in patients with alcoholic liver injury

BACKGROUND

The present study aims to investigate the effect of Lactobacillus casei on lipid metabolism and intestinal microflora in patients with alcoholic liver injury.

METHODS

In a double-blind randomized controlled trial, 158 recruited alcoholic liver injury patients were randomized to three treatments for 60 days: low-dose group (LP, n = 58, 100 ml of Lactobacillus casei strain Shirota (LcS)), high-dose group (HP, n = 54, 200 ml of LcS), and positive control group (PC, n = 46, 100 ml of special drinks without active Lactobacillus casei). Another group of 20 healthy people was served as normal control group (NC).

RESULTS

The serum levels of TG and LDLC in the HP group were significantly decreased by 26.56% and 23.83%, respectively than those in the PC group (P < 0.05). After supplementation of Lactobacillus casei, there was a significant increase in the amount of Lactobacillus and Bifidobacterium when compared with the PC group (P < 0.05).

CONCLUSIONS

Supplementation of Lactobacillus casei can improve lipid metabolism and regulate intestinal flora disorders in patients with alcoholic liver injury.

Lactobacillus plantarum KLDS1.0344 and Lactobacillus acidophilus KLDS1.0901 Mixture Prevents Chronic Alcoholic Liver Injury in Mice by Protecting the Intestinal Barrier and Regulating Gut Microbiota and Liver-Related Pathways

Health and wellbeing are significantly impaired by alcoholic liver disease (ALD), and although some lactic acid bacteria strains have been shown previously to relieve ALD symptoms, the mechanisms behind these effects are still unclear. Here, the Lieber-DeCarli liquid diet containing alcohol was fed to C57BL/6J mice for 6 weeks to build a chronic alcoholic liver lesion model to study the protective effects and possible mechanisms of Lactobacillus mixture (Lactobacillus plantarum KLDS1.0344 and Lactobacillus acidophilus KLDS1.0901). The results showed that Lactobacillus mixture improved intestinal epithelial permeability and reduced the serum lipopolysaccharide (LPS) levels. Furthermore, Lactobacillus mixture inhibited liver lipid accumulation, oxidative stress, and inflammation by regulating AMPK, Nrf-2, and TLR4/NF-κB pathways. Importantly, the Lactobacillus mixture modulated the gut microbiota, resulting in increased short-chain fatty acid (SCFA) producers and decreased Gram-negative bacteria. Taken together, these findings indicated that the Lactobacillus mixture could positively regulate the gut microbiota, causing increased levels of SCFAs, which inhibited alcohol-induced liver lipid accumulation and oxidative stress through the gut-liver axis. Moreover, following administration of the Lactobacillus mixture, the improvement of intestinal epithelial permeability and the reduction of Gram-negative bacteria led to the decrease of LPS entering the portal vein, thereby inhibiting alcohol-induced liver inflammation.

Regulation of uridine diphosphate-glucuronosyltransferase 1A expression by miRNA-214-5p and miRNA-486-3p

Aim: This study aimed to identify novel miRNAs (miRs) as regulators of UGT1A gene expression and to evaluate them as potential risk factors for the development of liver fibrosis/cirrhosis. Materials & methods: miRNA target sites in UDP-glucuronosyltransferase 1A (UGT1A) 3'-UTR were predicted and confirmed by luciferase assays, quantitative real-time PCR and western blot using HEK293, HepG2 and Huh7 cells. UGT1A and miRNA expression were analyzed in cirrhotic patients and a mouse model of alcoholic liver fibrosis. Results: miR-214-5p and miR-486-3p overexpression reduced UGT1A mRNA, protein levels and enzyme activity in HepG2 and Huh7 cells. miR-486-3p was upregulated in cirrhotic patients and fibrotic mice livers, whereas UGT1A mRNA levels were reduced. Conclusion: In conclusion, we identified two novel miRNAs capable to repress UGT1A expression in vitro and in vivo. Furthermore, miR-486-3p may represent a potential risk factor for the development or progression of liver fibrosis/cirrhosis by means of a reduced UGT1A-mediated detoxification activity.

Curcumin Can be Acts as Effective agent for Prevent or Treatment of Alcohol-induced Toxicity in Hepatocytes: An Illustrated Mechanistic Review

Previous studies have shown that alcohol abuse can cause serious liver damage and cirrhosis. The main pathway for these types of hepatocellular cell neurodegeneration is mitochondrial dysfunction, which causes lipid peroxidation and dysfunction of the glutathione ring and the defect of antioxidant enzymes in alcoholic hepatic cells. Alcohol can also initiate malicious inflammatory pathways and trigger the initiation and activation of intestinal and extrinsic apoptosis pathways in hepatocellular tissues that lead to cirrhosis. Previous studies have shown that curcumin may inhibit lipid peroxidation, glutathione dysfunction and restore antioxidant enzymes. Curcumin also modulates inflammation and the production of alcohol-induced biomarkers. Curcumin has been shown to play a critical role in the survival of alcoholic hepatocellular tissue. It has been shown that curcumin can induce and trigger mitochondrial biogenesis and, by this mechanism, prevent the occurrence of both intrinsic and extrinsic apoptosis pathways in liver cells that have been impaired by alcohol. According to this mechanism, curcumin may protect hepatocellular tissue from alcohol-induced cell degeneration and may therefore survive alcoholic hepatocellular tissue. . Based on these mechanisms, the protective functions of curcumin against alcohol-induced cell degeneration due to oxidative stress, inflammation, and apoptosis events in hepatocellular tissue have been recorded. Hence, in this research, we have attempted to evaluate and analyze the main contribution mechanism of curcumin cell defense properties against alcohol-induced hepatocellular damage, according to previous experimental and clinical studies, and in this way we report findings from major studies.

Effects of taraxasterol against ethanol and high-fat diet-induced liver injury by regulating TLR4/MyD88/NF-κB and Nrf2/HO-1 signaling pathways

Studies have reported that taraxasterol (TAR) is effective in the treatment of immune liver injury and alcoholic liver injury. The mechanism of action is mainly related to the inhibition of inflammation. To determine the key molecular mechanisms for the effect of TAR on alleviating ethanol and high-fat diet-induced liver injury, pathological morphology, biochemistry, oxidative stress, inflammatory response and lipid metabolism were examined. Our results showed that TAR could inhibit ethanol-induced hepatocyte death or lipid accumulation, and suppress oxidative stress, inflammatory response and lipid metabolism disorders. More specifically, ethanol-induced TLR-4 and MyD88 inflammatory response were down-regulated, when treated with TAR. Production of CYP2E1, Nrf2 and HO-1, which produced in response to increased oxidative stress, were regulated in TAR treated, ethanol-induced hepatocytes. In summary, TAR could inhibit the inflammatory response and oxidative stress, which was related to the regulation of TAR on TLR-4/MyD88/NF-κB and Nrf2/HO-1 pathways.

Oxidative stress in alcohol-related liver disease

Alcohol consumption is one of the leading causes of the global burden of disease and results in high healthcare and economic costs. Heavy alcohol misuse leads to alcohol-related liver disease, which is responsible for a significant proportion of alcohol-attributable deaths globally. Other than reducing alcohol consumption, there are currently no effective treatments for alcohol-related liver disease. Oxidative stress refers to an imbalance in the production and elimination of reactive oxygen species and antioxidants. It plays important roles in several aspects of alcohol-related liver disease pathogenesis. Here, we review how chronic alcohol use results in oxidative stress through increased metabolism via the cytochrome P450 2E1 system producing reactive oxygen species, acetaldehyde and protein and DNA adducts. These trigger inflammatory signaling pathways within the liver leading to expression of pro-inflammatory mediators causing hepatocyte apoptosis and necrosis. Reactive oxygen species exposure also results in mitochondrial stress within hepatocytes causing structural and functional dysregulation of mitochondria and upregulating apoptotic signaling. There is also evidence that oxidative stress as well as the direct effect of alcohol influences epigenetic regulation. Increased global histone methylation and acetylation and specific histone acetylation inhibits antioxidant responses and promotes expression of key pro-inflammatory genes. This review highlights aspects of the role of oxidative stress in disease pathogenesis that warrant further study including mitochondrial stress and epigenetic regulation. Improved understanding of these processes may identify novel targets for therapy.

p-Coumaric acid attenuates alcohol exposed hepatic injury through MAPKs, apoptosis and Nrf2 signaling in experimental models

Overconsumption of alcohol could lead to severe liver injury that connects with oxidative stress, apoptosis, and inflammatory response. Previously, we proved that p-coumaric acid prevents ethanol induced reproductive toxicity; however, p-coumaric acid (PCA) on ethanol mediated hepatotoxicity has not been examined yet. In our work, we sought to study the potential of PCA in contradiction of ethanol induced hepatoxicity which linking with MAPKs, apoptosis, oxidative stress, and Nrf2 signaling. Foremost, we found that PCA could protect ethanol induced both L-02 and HepG2 hepatic cells by inhibiting cytotoxicity, ROS production, mitochondrial depolarization, and nuclear fragmentation. Also, in vivo experiments showed that the ethanol increasing the lipid markers (TBARS, CD) and depletes the antioxidants thereby increased phosphorylation of JNK, ERK, and p38 in rat liver tissues. Interestingly, PCA treatments inhibit ethanol exposed lipid markers and depletion of antioxidants, which directs the inhibition of MAPKs activation in rat liver tissues. We also noticed that the PCA protected ethanol induced apoptosis and liver markers by inhibiting the expression of Bax, caspases; AST, ALT, ALS, and LDH in liver tissue. Overall, the ameliorative consequence of PCA on ethanol induced oxidative stress and apoptosis was achieved by suppressing the expression of CYP2E1 and overexpressing Nrf2 and its target protein HO-1 in rat liver tissue. As a result, PCA was marked to be an effective antioxidant with notable hepatoprotection by inhibiting MAPKs and apoptosis signaling via enhancing Nrf2 signaling.

Aronia melanocarpa Prevents Alcohol-Induced Chronic Liver Injury via Regulation of Nrf2 Signaling in C57BL/6 Mice

Aronia melanocarpa (AM), which is rich in anthocyanins and procyanidins, has been reported to exert antioxidative and anti-inflammatory effects. This study aimed to systematically analyze the components of AM and explore its effects on alcohol-induced chronic liver injury in mice. A component analysis of AM revealed 17 types of fatty acids, 17 types of amino acids, 8 types of minerals, and 3 types of nucleotides. Chronic alcohol-induced liver injury was established in mice via gradient alcohol feeding over a period of 6 months, with test groups orally receiving AM in the last 6 weeks. AM administration yielded potential hepatoprotective effects by alleviating weight gain and changes in organ indexes, decreasing the ratio of alanine aminotransferase/aspartate aminotransferase, reducing lipid peroxidation, enhancing antioxidant activities, decreasing oxidation-related factor levels, and regulating inflammatory cytokine levels. Histological analyses suggest that AM treatment markedly prevented organ damage in alcohol-exposed mice. Furthermore, AM activated nuclear factor erythroid 2-like 2 (Nrf2) by downregulating the expression of Kelch-like ECH-associated protein 1, resulting in elevated downstream antioxidative enzyme levels. AM activated Nrf2 via modulation of the phosphatidylinositol-3-hydroxykinase/protein kinase B signaling pathway. Altogether, AM prevented alcohol-induced liver injury, potentially by suppressing oxidative stress via the Nrf2 signaling pathway.

Physicochemical properties and hepatoprotective effects of glycated Snapper fish scale peptides conjugated with xylose via maillard reaction

The physicochemical properties and hepatoprotective effects of fish scales peptides (FSP) and the glycated peptides conjugated with xylose via Maillard reaction (FSP-MRPs) were investigated. Results showed that the FSP was rich in oligopeptides within 2-10 amino acids, the degree of grafting of FSP-MRPs was 52.97 ± 1.58% and the antioxidant activities in vitro of FSP were improved through Maillard reaction. In order to investigate the antioxidant activities of FSP-MRPs after digestion, the simulated gastrointestinal digestion experiments of FSP and FSP-MRPs in vitro were conducted. Results indicated that the antioxidant activities of FSP and FSP-MRPs remained as stronger as before even under the digestive conditions. Furthermore, FSP-MRPs could significantly reduce the elevated activities of serum aspartate aminotransferase and alanine aminotransferase, decrease the elevated the levels of hepatic malondialdehyde and triglyceride, and inhibit the decrease of hepatic superoxide dismutase, catalase and glutathione peroxidase caused by alcohol-induced liver damage. These findings suggest that the glycated peptides formed by FSP and xylose via Maillard reaction may be potential to be exploited as a potential functional ingredient in food industry.

The Connection of Periodontal Disease and Diabetes Mellitus: The Role of Matrix Metalloproteinases and Oxidative Stress

Diabetes mellitus, a chronic disease considered by the World Health Organization to be an epidemic, is now recognized as one of the factors behind the onset of periodontal disease. The connection between periodontal disease, which is an irreversible inflammatory disease of the supporting tissue of the teeth, and systemic diseases is reflected in the existence of common risk factors, subgingival dental biofilm, as a constant source of proinflamma-tory cytokines synthesized intensely in inflammatory periodontium. Diabetes mellitus leads to increased oxidative stress in periodontal tissues causing worsening of the disease and periodontopathy exacerbates deficiency of pancreatic β-cells. The most important role in primary inflammatory response in the pathogenesis of periodontopathy is played by neutrophils. Neutrophils cause periodontium destruction by the release of enzymes (matrix metalloproteinases), cytotoxic substances (free radicals, reactive oxygen and nitrogen species) and the expression of membrane receptors. Matrix metalloproteinases within the “protease network” are critical to many physiological and pathological processes, including immunity, inflammation, bone resorption and wound healing. Matrix metalloproteinases levels are elevated in patients with metabolic syndrome and diabetes mellitus, which may contribute to more frequent complications. In this paper, the review of available literature data shows the correlation between periodontal disease and diabetes mellitus, as well as the role of matrix metalloproteinases and oxidative stress in these. In this regard, determining the value of matrix metalloproteinases may be helpful in the diagnosis of periodontal disease complicated by diabetes mellitus. Also, the parameters of oxidative stress could help to clarify the mechanisms of pathogenesis and etiology of periodontal disease, or indicate the potential benefit of antioxidant supplementation in these individuals. As the role of matrix metalloproteinases has not been fully clarified in the pathogenesis of periodontopathy, additional studies will be needed to indicate their importance.

Lactobacillus rhamnosus Granules Dose-Dependently Balance Intestinal Microbiome Disorders and Ameliorate Chronic Alcohol-Induced Liver Injury

As the functions of Lactobacilli become better understood, there are increasing numbers of applications for Lactobacillus products. Previously, we have demonstrated that Lactobacillus rhamnosus GG (LGG) can prevent alcoholic liver injury. LGG granules were produced by fluid bed granulation with a media composed of starch, skimmed milk powder, whey powder, microcrystalline cellulose and maltose, and LGG fermented liquid that comprised 30-50% of the total weight. We found LGG granules dose-dependently protected against chronic alcoholic liver disease. When alcohol was consumed for 8 weeks with LGG treatment during the last 2 weeks, we demonstrated that the dose dependence of LGG granules can improve alcohol-induced liver injury through decreasing the levels of lipopolysaccharide and tumor necrosis factor-α in serum and prevent liver steatosis by suppressing triglyceride, free fatty acid, and malondialdehyde production in liver. Alcohol feeding caused a decline in the number of both Lactobacillus and Bifidobacterium, with a proportional increase in the number of Clostridium perfringens in ileum, and expansion of the Gram-negative bacteria Proteobacteria, Campylobacterales, and Helicobacter in cecum. However, LGG granule treatment restored the content of these microorganisms. In conclusion, LGG granule supplementation can improve the intestinal microbiota, reduce the number of gram-negative bacteria, and ameliorate alcoholic liver injury.

Glutathione deficiency-elicited reprogramming of hepatic metabolism protects against alcohol-induced steatosis

Depletion of glutathione (GSH) is considered a critical pathogenic event promoting alcohol-induced lipotoxicity. We recently show that systemic GSH deficiency in mice harboring a global disruption of the glutamate-cysteine ligase modifier subunit (Gclm) gene confers protection against alcohol-induced steatosis. While several molecular pathways have been linked to the observed hepatic protection, including nuclear factor erythroid 2-related factor 2 and AMP-activated protein kinase pathways, the precise mechanisms are yet to be defined. In this study, to gain insights into the molecular mechanisms underpinning the protective effects of loss of GCLM, global profiling of hepatic polar metabolites combined with liver microarray analysis was carried out. These inter-omics analyses revealed both low GSH- and alcohol-driven changes in multiple cellular pathways involving the metabolism of amino acids, fatty acid, glucose and nucleic acids. Notably, several metabolic changes were uniquely present in alcohol-treated Gclm-null mouse livers, including acetyl-CoA enrichment and diversion of acetyl-CoA flux from lipogenesis to alterative metabolic pathways, elevation in glutamate concentration, and induction of the glucuronate pathway and nucleotide biosynthesis. These metabolic features reflect low GSH-elicited cellular response to chronic alcohol exposure, which is beneficial for the maintenance of hepatic redox and metabolic homeostasis. The current study indicates that fine-tuning of hepatic GSH pool may evoke metabolic reprogramming to cope with alcohol-induced cellular stress.

Study on the synergistic protective effect of Lycium barbarum L. polysaccharides and zinc sulfate on chronic alcoholic liver injury in rats

Both Lycium barbarum L. polysaccharides (LBP) and zinc have protective effects on liver injuries. In this paper, LBP and ZnSO4 were combined to study the effects on the prevention of alcoholic liver injury. The rats were divided into six groups, the normal group, alcohol group, zinc sulfate group, LBP group, low-dose group of ZnSO4, and high-dose group of ZnSO4 and LBP, used to explore the impact of LBP and ZnSO4 complex on liver lipid metabolism of alcohol, alcohol-metabolizing enzymes, oxidative damage, and inflammation of the liver. The experimental model was established by gavage treatment, observation, and determination of indexes of rats. The results showed that the combination of LBP and ZnSO4 could significantly decrease the levels of triglyceride (TG), total cholesterol (TC), tumor necrosis factor-α(TNF-ɑ), malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the activity of enzyme subtype 2E1 (CYP2E1). It also significantly increased the activities of total superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione peptide (GSH), and alcohol dehydrogenase, effectively improved the liver tissue lesion. What is more, the combination of LBP and ZnSO4 had a synergistic effect on the remission of alcoholic fatty liver, and alleviated chronic alcoholic liver injury by promoting lipid metabolism, inhibiting oxidative stress, controlling inflammatory responses, and regulating the expression and activity of alcohol-metabolizing enzymes in rats.

Occludin endocytosis is involved in the disruption of the intestinal epithelial barrier in a mouse model of alcoholic steatohepatitis

OBJECTIVE

We aimed to investigate the involvement of the endocytosis of occludin, a key component of tight junction (TJ), in the ethanol-induced disassembly of TJ in a model of alcoholic steatohepatitis.

METHODS

Wild-type mice were fed an ethanol-containing or isocaloric liquid diet for 8 weeks and then assessed for liver injury (histopathology and measurement of serum enzymes), gut permeability (in vivo lactulose/mannitol and ex vivo dye leakage assays), intestinal epithelium ultrastructure (transmission electron microscopy), and intestinal occludin localization (immunofluorescence microscopy). The human intestinal epithelial cell line Caco-2 was also analyzed in vitro for the effects of ethanol on the barrier function (transepithelial electrical resistance), occludin localization (immunofluorescence microscopy and Western blotting), and endocytosis pathways (double-labeling immunofluorescence microscopy with selective pathway inhibitors).

RESULTS

The ethanol-fed mice developed steatohepatitis and displayed intestinal barrier dysfunction, the disruption of intestinal TJ, and enhanced intestinal endocytosis of occluding compared with the control mice. In the Caco-2 monolayers, ethanol treatment decreased transepithelial electrical resistance, disrupted TJ formation, and enhanced occludin endocytosis in a dose- and time-dependent manner. These deleterious events were reversed by pretreating the Caco-2 cells with a selective pharmacological inhibitor of macropinocytosis, but not with the inhibitors of clathrin or caveolin-mediated endocytic pathways.

CONCLUSION

Chronic ethanol exposure may increase intestinal permeability by inducing the micropinocytosis of occludin, resulting in the disruption of intestinal TJ.

Relative protective activities of quercetin, quercetin-3-glucoside, and rutin in alcohol-induced liver injury

Alcoholic liver diseases has been known to be one of the major health risks worldwide. The purpose of this study was aimed to demonstrate the relative protective effect of quercetin, quercetin-3-glucoside, and rutin on alcohol-induced damage in hepatocytes. The hepatotoxicity, antioxidant enzymatic defense mechanisms, and pro-inflammatory mediators were examined for evaluating the hepatoprotective effects of quercetins in hepG2 cells. The results revealed that quercetin and its glucoside derivatives significantly prevented ethanol-induced hepatotoxicity by decreasing hepatic aminotransferase activities and inflammatory response in HepG2 cells. Moreover, the quercetins significantly induced detoxifying enzymes via the nuclear accumulation of the NF-E2-related factor 2 (Nrf2) and induction of antioxidant response element (ARE) gene. These hepatoprotective activities were observed to be more effective with quercetin aglycone than quercetin glucosides. From the above findings, the present study imply that quercetin aglycone may have a vital function in the therapeutic and preventive strategies of alcoholic liver diseases. PRACTICAL APPLICATIONS: Quercetin is commonly present in fruits and vegetables as aglycone and glucoside-derived forms. In the present study, quercetin and its glycosides was shown to alleviate oxidative stress, glutathione depletion, and pro-inflammatory cytokines in alcohol-induced HepG2 cells via the Nrf2/ARE antioxidant pathway. Moreover, quercetin aglycone had better protective effects against alcohol-induced liver damage in vitro, compared to its glycosylated form. The present study proposed that quercetin aglycone may be a more efficient hepatoprotective agent than its glucoside derivatives such as rutin in the amelioration of alcohol-induced liver diseases.

Antioxidant Activity of Graptopetalum paraguayense E. Walther Leaf Extract Counteracts Oxidative Stress Induced by Ethanol and Carbon Tetrachloride Co-Induced Hepatotoxicity in Rats

(1) Background: Graptopetalum paraguayense E. Walther is a traditional Chinese herbal medicine. In our previous study, 50% ethanolic G. paraguayense extracts (GE50) demonstrated good antioxidant activity. (2) Methods: To investigate the hepatoprotective effects of GE50 on ethanol and carbon tetrachloride (CCl₄) co-induced hepatic damage in rats, Sprague–Dawley rats were randomly divided into five groups (Control group; GE50 group, 0.25 g/100 g BW; EC group: Ethanol + CCl₄, 1.25 mL 50% ethanol and 0.1 mL 20% CCl₄/100 g BW; EC + GE50 group: Ethanol + CCl₄ + GE50; EC + silymarin group: ethanol + CCl₄ + silymarin, 20 mg/100 g BW) for six consecutive weeks. (3) Results: Compared with the control group, EC group significantly elevated the serum aspartate aminotransferase (AST), alanine aminitransferase (ALT), and lactate dehydrogenase (LDH). However, GE50 or silymarin treatment effectively reversed these changes. GE50 had a significant protective effect against ethanol + CCl₄ induced lipid peroxidation and increased the levels of glutathione (GSH), vitamin C, E, total antioxidant status (TAS), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and glutathione S-transferases (GST). Furthermore, in EC focal group, slight fat droplet infiltration was observed in the livers, while in the GE50 or silymarin treatment groups, decreased fat droplet infiltration. HPLC phytochemical profile of GE50 revealed the presence of gallic acid, flavone, genistin, daidzin, and quercetin. (4) Conclusions: The hepatoprotective activity of GE50 is proposed to occur through the synergic effects of its chemical component, namely, gallic acid, flavone, genistin, daidzin, and quercetin. Hence, G. paraguayense can be used as a complementary and alternative therapy in the prevention of alcohol + CCl₄-induced liver injury.

S100A4 promotes inflammation but suppresses lipid accumulation via the STAT3 pathway in chronic ethanol-induced fatty liver

S100A4, a member of the S100 calcium-binding protein family, has been identified in a subpopulation of liver macrophages and promotes liver fibrosis via hepatic stellate cell activation. However, the specific role of S100A4 in alcoholic liver disease (ALD) has not been well investigated. Here, S100A4 knockout (S100A4^-/-) mice were used in a chronic-binge ethanol model for studying the role of S100A4 and its related molecular mechanism in ALD. S100A4 expression was increased in ethanol-induced liver tissues of wild-type (WT) mice. Macrophage-derived S100A4 promoted liver inflammation but suppressed lipid accumulation under the ethanol feeding condition. S100A4 deficiency promoted ethanol-induced liver injury and hepatic fat accumulation. Further mechanistic studies found that S100A4 inhibited liver fat accumulation mainly by activating the STAT3 pathway and downregulating lipogenic gene expression, especially that of SREBP-1c. In AML-12 cells, a STAT3 inhibitor abolished STAT3 levels and decreased the expression of SREBP1c. Furthermore, the administration of a neutralizing S100A4 antibody to WT mice significantly promoted ethanol-induced liver injury and fatty accumulation. Thus, S100A4 may represent a potential candidate target for the prevention and treatment of ethanol-induced fatty liver. In this study, we discovered the special role of S100A4 in alcoholic liver disease. S100A4 deficiency attenuated ethanol-induced hepatitis and promoted hepatic fat accumulation in ethanol-induced liver tissues. Further mechanistic studies have found that S100A4 promotes early alcoholic hepatitis mainly by activating the STAT3 pathway and its downstream proinflammatory gene expression. Interestingly, activation of the STAT3 pathway downregulates lipogenic gene expression, especially SREBP-1c. KEY MESSAGES: In this study, we discovered the special role of S100A4 in alcoholic liver disease. S100A4 deficiency attenuated ethanol-induced hepatitis and promoted hepatic fat accumulation in ethanol-induced liver tissues. Further mechanistic studies have found that S100A4 promotes early alcoholic hepatitis mainly by activating the STAT3 pathway and its downstream proinflammatory gene expression. Interestingly, activation of the STAT3 pathway downregulates lipogenic gene expression, especially SREBP-1c.

Probiotics for Alleviating Alcoholic Liver Injury

Many animal experiments and clinical trials showed that probiotics are effective for the treatment of alcoholic liver disease. Alcohol disrupts the composition of intestinal flora; probiotics modulate the gut microbiota and reverse alcohol-associated intestinal barrier dysfunction by decreasing intestinal mucosal permeability and preventing intestinal bacteria from translocating. Probiotics enhance immune responses and reduce the levels of alcohol-induced inflammatory cytokines and reactive oxygen species (ROS) production in the liver and intestine. Probiotics also increase fatty acid β-oxidation and reduce lipogenesis, combating alcohol-induced hepatic steatosis. In this review, we summarize the current knowledge regarding the mechanism of action of probiotics for reducing the effects of alcoholic liver disease.

Phosphoinositide-specific phospholipase C in normal human liver and in alcohol abuse

The phosphoinositide (PI) signal transduction pathway participates in liver metabolism. Abnormal activity or expression of PI-specific phospholipase C (PLC) enzymes has been described in different liver diseases. We resume the role of the PI metabolism in liver and PLC abnormalities in different liver diseases. Moreover, we present the results of PLC analyses in a normal human liver and an alcohol-damaged liver. PLC enzymes and the expression of the corresponding genes in liver biopsies from individuals deceased for complications of the alcoholic liver disease (ALD) at different stages compared with normal controls (deceased individuals with histologically normal livers without alcohol addiction anamnesis) were analyzed by using immunohistochemistry and molecular biology techniques. The expression panel of PLCs was described in normal and alcohol abuse liver. Our observations suggest that the regulation of PLC expression might be due to posttranscriptional events and that alcohol affects the epigenetic control of PLC expression belonging to PI signaling. We also describe the alternate expression of PLCB1 and PLCH1 genes in liver. Our results corroborate literature data suggesting that PLC enzymes are differently expressed in normal versus pathological liver, playing a role in the histopathogenesis of liver tissue damage. The expression and/or localization of selected PLC isoforms is especially affected in alcohol-related liver tissue histopathology. Our present observations confirm that the modulation of protein synthesis plays a role in the regulation of PLC enzymes. We also suggest that this modulation might act at the transcription level. Further studies are required to investigate related epigenetic mechanisms.

Bombax ceiba flowers extract ameliorates hepatosteatosis induced by ethanol and relatively moderate fat diet in rats

Chronic excessive alcohol consumption could induce serious liver injury. In this study, therapeutic effect of aqueous methanol extract of Bombax ceiba L. flowers (BCE) (Family: Bombacaceae) was investigated against hepatic steatosis. This study included seven groups, and the research period was eight weeks. The first group served as control. The six remaining groups were divided into two categories, three groups in each. The first category was fed fat diet. The second category was fed fat diet and orally administrated ethanol, which was given in graduate doses from 2 g/kg/d to 6 g/kg/d. Then, one group from each category was orally treated with the standard drug fluvastatin (2 mg/Kg/d). Another group was orally treated with BCE (200 mg/kg/d). The third group left untreated. The results revealed that BCE significantly decrease both the body and liver weight. The treatment with BCE extract also ameliorates the effect of alcohol induced increase of liver enzyme activities. In addition, the extract was significantly increased hepatic liver antioxidants and decreased malondialdehyde (MDA) level. Also, serum lipid profiles: triglycerides (TG), total cholesterol (TC) and low density lipoprotein (LDL) were significantly decreased after BCE treatment. Histopathological study showed fatty changes induced by alcohol which were improved by BCE treatment. These data suggest that the BCE has anti-inflammatory, anti-oxidant and anti-steatosis potential properties against alcohol induced liver damage. This may be due to the presence of flavonoids and other phenol compounds.

Hepatic metabolic adaptation in a murine model of glutathione deficiency

Glutathione (GSH), the most abundant cellular non-protein thiol, plays a pivotal role in hepatic defense mechanisms against oxidative damage. Despite a strong association between disrupted GSH homeostasis and liver diseases of various etiologies, it was shown that GSH-deficient glutamate-cysteine ligase modifier subunit (Gclm)-null mice are protected against fatty liver development induced by a variety of dietary and environmental insults. The biochemical mechanisms underpinning this protective phenotype have not been clearly defined. The purpose of the current study was to characterize the intrinsic metabolic signature in the livers from GSH deficient Gclm-null mice. Global profiling of hepatic polar metabolites revealed a spectrum of changes in amino acids and metabolites derived from fatty acids, glucose and nucleic acids due to the loss of GCLM. Overall, the observed low GSH-driven metabolic changes represent metabolic adaptations, including elevations in glutamate, aspartate, acetyl-CoA and gluconate, which are beneficial for the maintenance of cellular redox and metabolic homeostasis.