The role of oxidative stress in the development of alcoholic liver disease

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Effect of Europinidin against Alcohol-Induced Liver Damage in Rats by Inhibiting the TNF-α/TGF-β/IFN-γ/NF-kB/Caspase-3 Signaling Pathway

BACKGROUND

The effect of europinidin on alcoholic liver damage in rats was examined in this research.

METHODS

A total of 24 Wistar rats were grouped in the same way into four groups: normal control (normal), ethanol control (EtOH), europinidin low dose (10 mg/kg), and europinidin higher dose (20 mg/kg). The test group rats were orally treated with europinidin-10 and europinidin-20 for 4 weeks, whereas 5 mL/kg distilled water was administered to control rats. In addition, 1 h after the last dose of the above-mentioned oral treatment, 5 mL/kg (i.p.) EtOH was injected to induce liver injury. After 5 h of EtOH treatment, samples of blood were withdrawn for biochemical estimations.

RESULTS

Administration of europinidin at both doses restored all of the estimated serum, i.e., liver function tests (ALT, AST, ALP), biochemical test (Creatinine, albumin, BUN, direct bilirubin, and LDH), lipid assessment (TC and TG), endogenous antioxidants (GSH-Px, SOD, and CAT), malondialdehyde (MDA), nitric oxide (NO), cytokines (TGF-β, TNF-α, IL-1β, IL-6, IFN-γ, and IL-12), caspase-3, and nuclear factor kappa B (NF-κB) associated with the EtOH group.

CONCLUSION

The results of the investigation showed that europinidin had favorable effects in rats given EtOH and may have hepatoprotective potential property.

Role of silymarin as antioxidant in clinical management of chronic liver diseases: a narrative review

Chronic liver disease (CLD), manifested as hepatic injury, is a major cause of global morbidity and mortality. CLD progresses to fibrosis, cirrhosis, and-ultimately-hepatocellular carcinoma (HCC) if left untreated. The different phenotypes of CLD based on their respective clinical features and causative agents include alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), metabolic-associated fatty liver disease (MAFLD), and drug-induced liver injury (DILI). The preferred treatment modality for CLD includes lifestyle modification and diet, along with limited pharmacological agents for symptomatic treatment. Moreover, oxidative stress (OS) is an important pathological mechanism underlying all CLD phenotypes; hence, the use of antioxidants to manage the disease is justified. Based on available clinical evidence, silymarin can be utilized as a hepatoprotective agent, given its potent antioxidant, antifibrotic, and anti-inflammatory properties. The role of silymarin in suppressing OS has been well established, and therefore silymarin is recommended for use in ALD and NAFLD in the guidelines approved by the Russian Medical Scientific Society of Therapists and the Gastroenterology Scientific Society of Russia. However, to discuss the positioning of the original silymarin in clinical guidelines and treatment protocols as a hepatoprotective agent for managing CLD concomitantly with other therapies, an expert panel of international and Russian medical professionals was convened on 11 November 2020. The panel reviewed approaches for the prevention and treatment of OS, existing guidelines for patient management for CLD, and available evidence on the effectiveness of silymarin in reducing OS, fibrosis, and hepatic inflammation and presented in the form of a narrative review. Key messagesAn expert panel of international and Russian medical professionals reviewed existing guidelines for ALD, NAFLD, MAFLD, and DILI to establish consensus recommendations that oxidative stress is the common pathophysiological mechanism underlying these conditions.The panel also discussed the positioning of original silymarin in clinical guidelines and treatment protocols as a hepatoprotective agent for managing CLD concomitantly with other therapies.The panel reviewed the effectiveness of 140 mg original silymarin three times a day in reducing oxidative stress in chronic liver diseases such as ALD, NAFLD, MAFLD, and DILI.

Probiotic Lactobacilli ameliorate alcohol-induced hepatic damage via gut microbial alteration

Alcoholic liver disease (ALD), which includes fatty liver, cirrhosis, steatosis, fibrosis, and hepatocellular carcinoma, is a global health problem. The probiotic effects of lactic acid bacteria (LAB) are well-known; however, their protective effect against ALD remains unclear. Therefore, in this study, our objective was to assess the protective effects of LAB on ALD. To this end, mice were fed either a normal diet or an alcohol diet for 10 days (to induce ALD) accompanied by vehicle treatment (the NC and AC groups) or kimchi-derived LAB (Lactiplantibacillus plantarum DSR J266 and Levilactobacillus brevis DSR J301, the AL group; or Lacticaseibacillus rhamnosus GG, the AG group). Our results showed that mice in the AC group showed significantly higher serum aspartate aminotransferase and alanine aminotransferase levels than those in the normal diet groups; however, their levels in the AL and AG groups were relatively lower. We also observed that the AL and AG groups showed relatively lower interleukin-6 levels than the AC group. Additionally, AC group showed the accumulation of several fat vesicles in the liver, while the AL and AG groups showed remarkably lower numbers of fat vesicles. The relative abundance of Enterococcus feacalis, which showed association with liver injury, significantly increased in the AC group compared with its levels in the normal diet groups. However, the AG group showed a decreased relative abundance in this regard, confirming that LAB exerted an improvement effect on gut microbial community. These findings suggested that via gut microbiota alteration, the ingestion of LAB can alleviate the ill effects of alcohol consumption, including inflammation, liver damage, gut dysbiosis, and abnormal intestinal nutrient metabolism.

Anti-Oxidant and Anti-Inflammatory Effects of Lipopolysaccharide from Rhodobacter sphaeroides against Ethanol-Induced Liver and Kidney Toxicity in Experimental Rats

This study aimed to investigate the protective effects of lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS) against ethanol-induced hepatotoxicity and nephrotoxicity in experimental rats. The study involved an intact control group, LPS-RS group, two groups were given ethanol (3 and 5 g/kg/day) for 28 days, and two other groups (LPS-RS + 3 g/kg ethanol) and (LPS-RS + 5 g/kg ethanol) received a daily dose of LPS-RS (800 μg/kg) before ethanol. Ethanol significantly increased the expression of nuclear factor kappa B (NF-κB) and levels of malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in the liver tissue and decreased anti-oxidant enzymes. Hepcidin expression was downregulated in the liver, with increased serum levels of ferritin and iron. Prior-administration of LPS-RS alleviated the increase in oxidative stress and inflammatory markers, and preserved iron homeostasis markers. In the kidney, administration of ethanol caused significant increase in the expression of NF-κB and the levels of TNF-α and kidney injury markers; whereas LPS-RS + ethanol groups had significantly lower levels of those parameters. In conclusion; this study reports anti-oxidant, anti-inflammatory and iron homeostasis regulatory effects of the toll-like receptor 4 (TLR4) antagonist LPS-RS against ethanol induced toxicity in both the liver and the kidney of experimental rats.

Gender differences in the associations of multiple psychiatric and chronic conditions with major depressive disorder among patients with opioid use disorder

PURPOSE

The study examined the associations of multiple psychiatric and chronic conditions with the self-reported history of major depressive disorder (MDD) among patients with opioid use disorder (OUD) and tested whether the associations differed by gender.

METHODS

We conducted a secondary data analysis of baseline data from a clinical trial including 1,646 participants with OUD, of which 465 had MDD. A variable cluster analysis was used to classify chronic medical and psychiatric conditions. Multivariable logistic regression analyses were used to estimate their associations with MDD in subjects with OUD.

RESULTS

Nine variables were divided into three clusters: cluster 1 included heart condition, hypertension, and liver problems; cluster 2 included gastrointestinal (GI) problems and head injury, and cluster 3 included anxiety disorder, bipolar disorder, and schizophrenia. The overall prevalence of MDD in participants with OUD was 28.3% (22.8% for males and 39.5% for females). Gender, anxiety disorder, schizophrenia, liver problems, heart condition, GI problems, and head injury were significantly associated with MDD. Gender-stratified analyses showed that bipolar disorder, liver problems and individuals with one chronic condition were associated with MDD only in males, whereas heart condition, hypertension, and GI problems were associated with MDD only in females. In addition, anxiety disorder, head injury, individuals with one or more than two psychiatric conditions, and individuals with more than two chronic conditions were associated with MDD regardless of gender.

CONCLUSIONS

Treatment plans in patients with OUD should not only address MDD but also co-morbid psychiatric and chronic medical conditions that occur with MDD.

Alcohol Binge Drinking Selectively Stimulates Protein S-Glutathionylation in Aorta and Liver of ApoE -/- Mice

Background: Binge drinking has become the most common and deadly pattern of excessive alcohol use in the United States, especially among younger adults. It is closely related to the increased risk of cardiovascular disease. Oxidative stress as a result of ethanol metabolism is the primary pathogenic factor for alcohol-induced end organ injury, but the role of protein S-glutathionylation-a reversible oxidative modification of protein cysteine thiol groups that mediates cellular actions by oxidants-in binge drinking-associated cardiovascular disease has not been explored. The present study defines the effect of alcohol binge drinking on the formation of protein S-glutathionylation in a mouse model of atherosclerosis. Methods and Results: To mimic the weekend binge drinking pattern in humans, ApoE deficient (ApoE -/-) mice on the Lieber-DeCarli liquid diet received ethanol or isocaloric maltose (as a control) gavages (5 g/kg/day, 2 consecutive days/week) for 6 weeks. The primary alcohol-targeted organs (liver, brain), and cardiovascular system (heart, aorta, lung) of these two groups of the mice were determined by measuring the protein S-glutathionylation levels and its regulatory enzymes including [Glutaredoxin1(Grx1), glutathione reductase (GR), glutathione-S-transferase Pi (GST-π)], as well as by assessing aortic endothelial function and liver lipid levels. Our results showed that binge drinking selectively stimulated protein S-glutathionylation in aorta, liver, and brain, which coincided with altered glutathionylation regulatory enzyme expression that is downregulated Grx1 and upregulated GST-π in aorta, massive upregulation of GST-π in liver, and no changes in Grx1 and GST-π in brain. Functionally, binge drinking induced aortic endothelial cell function, as reflected by increased aortic permeability and reduced flow-mediated vasodilation. Conclusions: This study is the first to provide in vivo evidence for differential effects of binge drinking on formation of protein S-glutathionylation and its enzymatic regulation system in major alcohol-target organs and cardiovascular system. The selective induction of protein S-glutathionylation in aorta and liver is associated with aortic endothelial dysfunction and fatty liver, which may be a potential redox mechanism for the increased risk of vascular disease in human binge-drinkers.

The Protective Effect of the Polysaccharide Precursor, D-Isofloridoside, from Laurencia undulata on Alcohol-Induced Hepatotoxicity in HepG2 Cells

Alcoholic liver disease (ALD) threatens human health, so it is imperative that we find ways to prevent or treat it. In recent years, the study of polysaccharides has shown that they have different kinds of bioactivities. Among them are many biological effects that have been attributed to polysaccharide precursors. D-Isofloridoside (DIF) is one of the polysaccharide precursors from the marine red alga Laurencia undulata. This study evaluated the effect of DIF on alcohol-induced oxidative stress in human hepatoma cells (HepG2). As a result, DIF attenuated alcohol-induced cytotoxicity, reduced the amount of intracellular reactive oxygen species (ROS), and effectively reduced alcohol-induced DNA damage in HepG2 cells. In addition, a western blot showed that, after DIF treatment, the expression levels of glutathione (GSH), superoxide dismutase (SOD), and B-cell lymphoma-2 (bcl-2) increased, while the expression levels of γ-glutamyl transferase (GGT), BCL2-associated X (bax), cleaved caspase-3, and mitogen-activated protein kinase (p38 and c-Jun N-terminal kinase) signal transduction proteins reduced. This showed that DIF may protect cells by reducing the amount of intracellular ROS and inhibiting intracellular oxidative stress and apoptotic processes. Finally, molecular docking demonstrated that DIF can bind to SOD, GGT, B-cell lymphoma-2, and bax proteins. These results indicated that DIF can protect HepG2 cells from alcohol-induced oxidative stress damage, making it an effective potential ingredient in functional foods.

Hepatoprotective Effect of the Ethanol Extract of Illicium henryi against Acute Liver Injury in Mice Induced by Lipopolysaccharide

The root bark of Illicium henryi has been used in traditional Chinese medicine to treat lumbar muscle strain and rheumatic pain. Its ethanol extract (EEIH) has been previously reported to attenuate lipopolysaccharide (LPS)-induced acute kidney injury in mice. The present study aimed to evaluate the in vitro antioxidant activities and in vivo protective effects of EEIH against LPS-induced acute liver injury (ALI) in mice as well as explore its molecular mechanisms. The mice were injected intraperitoneally (i.p.) with EEIH at the doses of 1.25, 2.5, and 5.0 mg/kg every day for 5 days. One hour after the last administration, the mice were administered i.p. with LPS (8 mg/kg). After fasting for 12 h, blood and liver tissues were collected to histopathological observation, biochemical assay, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot analyses. EEIH possessed 2,2-diphenyl-1-picrylhydrazil (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiozoline-6-sulfonic acid) disodium salt (ABTS) radical scavenging activities and ferric-reducing antioxidant capacity in vitro. The histopathological examination, serum biochemical analysis, and liver myeloperoxidase (MPO) activity showed that EEIH pretreatment alleviated LPS-induced liver injury in mice. EEIH significantly dose-dependently decreased the mRNA and protein expression levels of inflammatory factors TNF-α, IL-1β, IL-6, and COX-2 in liver tissue of LPS-induced ALI mice via downregulating the mRNA and protein expressions of toll-like receptor 4 (TLR4) and inhibiting the phosphorylation of nuclear factor-κB (NF-κB) p65. Furthermore, EEIH markedly ameliorated liver oxidative and nitrosative stress burden in LPS-treated mice through reducing the content of thiobarbituric acid reactive substances (TBARS), inducible nitric oxide synthase (iNOS), and nitric oxide (NO) levels, restoring the decreased superoxide dismutase (SOD) and reduced glutathione (GSH) levels, and up-regulating nuclear factor erythroid 2 related factor 2 (Nrf2). These results demonstrate that EEIH has protective effects against ALI in mice via alleviating inflammatory response, oxidative and nitrosative stress burden through activating the Nrf2 and suppressing the TLR4/NF-κB signaling pathways. The hepatoprotective activity of EEIH might be attributed to the flavonoid compounds such as catechin (1), 3',4',7-trihydroxyflavone (2), and taxifolin (7) that most possibly act synergistically.

Pathogenesis, Early Diagnosis, and Therapeutic Management of Alcoholic Liver Disease

Alcoholic liver disease (ALD) refers to the damages to the liver and its functions due to alcohol overconsumption. It consists of fatty liver/steatosis, alcoholic hepatitis, steatohepatitis, chronic hepatitis with liver fibrosis or cirrhosis, and hepatocellular carcinoma. However, the mechanisms behind the pathogenesis of alcoholic liver disease are extremely complicated due to the involvement of immune cells, adipose tissues, and genetic diversity. Clinically, the diagnosis of ALD is not yet well developed. Therefore, the number of patients in advanced stages has increased due to the failure of proper early detection and treatment. At present, abstinence and nutritional therapy remain the conventional therapeutic interventions for ALD. Moreover, the therapies which target the TNF receptor superfamily, hormones, antioxidant signals, and MicroRNAs are used as treatments for ALD. In particular, mesenchymal stem cells (MSCs) are gaining attention as a potential therapeutic target of ALD. Therefore, in this review, we have summarized the current understandings of the pathogenesis and diagnosis of ALD. Moreover, we also discuss the various existing treatment strategies while focusing on promising therapeutic approaches for ALD.

Modulatory effects of Viola odorata flower and leaf extracts upon oxidative stress-related damage in an experimental model of ethanol-induced hepatotoxicity

Ethanol is the most widely abused drug in the world and its long-term use induces oxidative stress in the liver tissue. The aim of this study was to evaluate protective effect of Viola odorata against ethanol-induced hepatotoxicity in Wistar rat. Animals were divided into 9 groups as follows: control (normal saline), ethanol (10 mg/kg, intraperitoneally), ethanol with 3 doses (125, 250, and 500 mg/kg) of ethyl acetate flower and leaf extracts, and positive control (vitamin E 80 mg/kg). Animals were gavaged 30 min before ethanol injection for 28 days. Then, animals were killed and the livers were separated. Oxidative stress parameters, including reactive oxygen species, lipid peroxidation, and protein carbonyl as well as glutathione content, were evaluated. Also, histopathological examination was performed and assessment of blood alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and total antioxidant capacity were evaluated. Ethanol significantly increased oxidative stress markers in liver. Interestingly, administration of both extracts significantly decreased oxidative stress markers in liver tissue and biochemical parameters in the plasma. In addition, abnormal pathological features were improved after treatment with flower and leaf extracts. These results suggested that V. odorata can be considered a candidate for improving conditions due to ethanol-induced tissue oxidative damage because of its antioxidant activity.

Fraxin Prevents Chemically Induced Hepatotoxicity by Reducing Oxidative Stress

Fraxin isolated from Acer tegmentosum is reported to exert potent anti-oxidative stress action. However, pharmacological activities of fraxin remain to be elucidated. This study investigated the potential hepatoprotective effects of fraxin and the underlying signaling mechanism involved. Treatment with fraxin significantly lowered the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a CCl₄-induced hepatotoxicity rat model. In the fraxin-treated group, glutathione (GSH) significantly increased, while the malondialdehyde (MDA) in the liver significantly decreased. Fraxin also showed radical-scavenging activity. Furthermore, it significantly reduced the t-BHP-induced cytotoxicity and production of reactive oxygen species (ROS) in Hep G2. Fraxin protected Hep G2 cells through Nrf2 pathway-dependent HO-1 expression. The results of this study indicate that fraxin shows potent hepatoprotective effects in vitro and in vivo, presumably through direct antioxidant activity and the Nrf2-mediated antioxidant enzyme system.

Silymarin/Silybin and Chronic Liver Disease: A Marriage of Many Years

Silymarin is the extract of Silybum marianum, or milk thistle, and its major active compound is silybin, which has a remarkable biological effect. It is used in different liver disorders, particularly chronic liver diseases, cirrhosis and hepatocellular carcinoma, because of its antioxidant, anti-inflammatory and antifibrotic power. Indeed, the anti-oxidant and anti-inflammatory effect of silymarin is oriented towards the reduction of virus-related liver damages through inflammatory cascade softening and immune system modulation. It also has a direct antiviral effect associated with its intravenous administration in hepatitis C virus infection. With respect to alcohol abuse, silymarin is able to increase cellular vitality and to reduce both lipid peroxidation and cellular necrosis. Furthermore, silymarin/silybin use has important biological effects in non-alcoholic fatty liver disease. These substances antagonize the progression of non-alcoholic fatty liver disease, by intervening in various therapeutic targets: oxidative stress, insulin resistance, liver fat accumulation and mitochondrial dysfunction. Silymarin is also used in liver cirrhosis and hepatocellular carcinoma that represent common end stages of different hepatopathies by modulating different molecular patterns. Therefore, the aim of this review is to examine scientific studies concerning the effects derived from silymarin/silybin use in chronic liver diseases, cirrhosis and hepatocellular carcinoma.

Heme oxygenase-1 alleviates alcoholic liver steatosis: histopathological study

Excessive alcohol consumption is one of the most important causes of hepatic steatosis, which involves oxidative stress. In particular, increased oxidative stress has been strongly linked to stimulation of the expression of heme oxygenase-1 (HO-1). This study aimed to investigate whether HO-1 could alleviates alcoholic steatosis in rats. Male Wistar rats were randomly divided into 4 groups: 1) the control group, 2) the EtOH group, 3) the EtOH + ZnPP-IX group and 4) the EtOH + Hemin group. Liver histopathology was investigated in weeks 1 and 4 after the start of the treatment period. Alcohol treatment significantly increased the hepatic malondialdehyde (MDA) levels, an oxidative stress marker. In addition, it increased the triglyceride, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in both weeks. Gross examination demonstrated a yellowish and slightly enlarged liver in the alcohol-treated rats. Hematoxylin and eosin (H&E) and Oil Red O staining indicated hepatic steatosis, which was characterized by diffuse, extensive fatty accumulation and discrete lipid droplets of variable size in hepatocytes of the alcohol-treated rats. Administration of the HO-1 inducer hemin resulted in upregulation of hepatic HO-1 gene expression, reduced the MDA, triglyceride, ALT and AST levels and alleviated alcoholic hepatic steatosis, whereas administration of the HO-1 inhibitor zinc protoporphyrin IX (ZnPP-IX) resulted in downregulation of hepatic HO-1 gene expression and could not alleviate alcoholic hepatic steatosis either week. In conclusion, HO-1 could alleviate alcoholic hepatic steatosis in male Wistar rats and may be useful in development of a new therapeutic approach.