N-acetylcysteine attenuates alcohol-induced oxidative stress in he rat

Multi-modal neuroimaging reveals differences in alcohol-cue reactivity but not neurometabolite concentrations in adolescents who drink alcohol

BACKGROUND

The objective of this multi-modal neuroimaging study was to identify neuroscience-informed treatment targets for adolescent alcohol use disorder (AUD) by examining potential neural alterations associated with adolescent alcohol use.

METHODS

Adolescents (ages 17-19) who heavily used (n=49) or did not use alcohol (n=22) were recruited for a multi-modal neuroimaging protocol, including proton magnetic resonance spectroscopy within the dorsal anterior cingulate cortex (dACC) and an fMRI alcohol cue-reactivity task. The alcohol cue-reactivity task was analyzed across 11 a priori regions-of-interest (ROI), including the dACC, and in an exploratory whole-brain approach. Correlations were run between neurometabolite levels and alcohol cue-reactivity in the dACC.

RESULTS

There were no significant group differences in absolute neurometabolite concentrations. Compared to the control group, the alcohol-using group exhibited heightened alcohol cue reactivity in the left amygdala ROI (p=0.04). The whole-brain approach identified higher alcohol cue reactivity in the alcohol-using group compared to controls in the amygdala and occipital regions, and lower reactivity in the parietal lobe. Whole-brain sex effects were noted, with females displaying higher reactivity regardless of group. No significant correlations were found between neurometabolite levels and alcohol cue-reactivity in the dACC.

CONCLUSIONS

The null neurometabolic findings may be due to age, relatively low severity of alcohol use, and non-treatment-seeking status of the participants. Females showed overall higher reactivity to alcohol cues, indicating a sex effect regardless of alcohol use history. Higher amygdala reactivity in alcohol-using adolescents suggests that emotional processing related to alcohol cues may be a useful target for future adolescent AUD interventions.

Combination of Cysteine and Glutathione Prevents Ethanol-Induced Hangover and Liver Damage by Modulation of Nrf2 Signaling in HepG2 Cells and Mice

Excessive alcohol consumption increases oxidative stress, leading to alcoholic liver disease. In this study, the protective effects of a mixture of cysteine and glutathione against ethanol-induced hangover and liver damage were evaluated in mice and HepG2 cells. Ethanol (2 mL/kg) was orally administered to the mice 30 min before receiving the test compounds (200 mg/kg), and the behavioral and oxidative stress-related biochemical parameters altered by ethanol were analyzed. Acute ethanol administration increased anxiety behavior and decreased balance coordination in mice (p < 0.001); however, a mixture of cysteine and glutathione (MIX) in a 3:1 ratio improved alcohol-induced behavior more effectively than the individual compounds (p < 0.001). The MIX group showed higher ethanol-metabolizing enzyme activity than the control group (p < 0.001) and significantly suppressed the elevation of serum alcohol (p < 0.01) and acetaldehyde (p < 0.001) levels after 1 h of ethanol administration. In HepG2 cells, 2.5 mM MIX accelerated ethanol metabolism and reduced cytochrome P450 2E1 mRNA expression (p < 0.001). MIX also increased the expression of antioxidant enzymes through the upregulation of nuclear erythroid 2-related factor 2 (Nrf2) signaling and consequently suppressed the overproduction of reactive oxygen species and malondialdehyde (p < 0.001). Collectively, MIX alleviates the hangover symptoms and attenuates the alcohol-induced oxidative stress by regulating the Nrf2 pathway.

N-acetylcysteine does not alter neurometabolite levels in non-treatment seeking adolescents who use alcohol heavily: A preliminary randomized clinical trial

Current treatments for adolescent alcohol use disorder (AUD) are mainly psychosocial and limited in their efficacy. As such, pharmacotherapies are being investigated as potential adjunctive treatments to bolster treatment outcomes. N-acetylcysteine is a promising candidate pharmacotherapy for adolescent AUD because of its tolerability and demonstrated ability to modulate glutamatergic, GABAergic, and glutathione systems. The primary objective of this double-blind, placebo-controlled, within-subjects crossover preliminary investigation was to measure potential changes within glutamate + glutamine (Glx), GABA, and glutathione levels in the dorsal anterior cingulate cortex (dACC) using proton magnetic resonance spectroscopy during 10-days of N-acetylcysteine (1200 mg twice daily) compared to 10-days of placebo in non-treatment seeking adolescents who use alcohol heavily (N = 31; 55% female). Medication adherence was confirmed via video. Effects on alcohol use were measured using Timeline Follow-Back as an exploratory aim. Linear mixed effects models controlling for baseline metabolite levels, brain tissue composition, alcohol use, cannabis use, and medication adherence found no significant differences in Glx, GABA, or glutathione levels in the dACC after N-acetylcysteine compared to placebo. There were also no measurable effects on alcohol use; however, this finding was underpowered. Findings were consistent in the subsample of participants who met criteria for AUD (n = 19). The preliminary null findings in brain metabolite levels may be due to the young age of participants, relatively low severity of alcohol use, and non-treatment seeking status of the population investigated. Future studies can use these findings to conduct larger, well-powered studies within adolescents with AUD.

Current Therapeutic Options and Potential of Mesenchymal Stem Cell Therapy for Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a globally prevalent chronic liver disease caused by chronic or binge consumption of alcohol. The therapeutic efficiency of current therapies for ALD is limited, and there is no FDA-approved therapy for ALD at present. Various strategies targeting pathogenic events in the progression of ALD are being investigated in preclinical and clinical trials. Recently, mesenchymal stem cells (MSCs) have emerged as a promising candidate for ALD treatment and have been tested in several clinical trials. MSC-released factors have captured attention, as they have the same therapeutic function as MSCs. Herein, we focus on current therapeutic options, recently proposed strategies, and their limitations in ALD treatment. Also, we review the therapeutic effects of MSCs and those of MSC-related secretory factors on ALD. Although accumulating evidence suggests the therapeutic potential of MSCs and related factors in ALD, the mechanisms underlying their actions in ALD have not been well studied. Further investigations of the detailed mechanisms underlying the therapeutic role of MSCs in ALD are required to expand MSC therapies to clinical applications. This review provides information on current or possible treatments for ALD and contributes to our understanding of the development of effective and safe treatments for ALD.

Ameliorative Impacts of Wheat Germ Oil against Ethanol-Induced Hepatic and Renal Dysfunction in Rats: Involvement of Anti-Inflammatory, Anti-Apoptotic, and Antioxidant Signaling Pathways

Wheat germ oil (WGO) is a well-known product with anti-inflammatory and antioxidant properties. The current study aimed to investigate the impacts of WGO against ethanol-induced liver and kidney dysfunction at the serum, anti-inflammatory, antioxidants and anti-apoptotic signaling pathways. Rats received saline orally as a negative control or WGO in a dose of 1.5 mL/kg (1400 mg/kg body weight orally) for 15 days. The affected group received ethanol 50% v/v 10 mL/kg (5 g/kg) body weight orally once a day for consecutive 15 days to induce hepatorenal injuries in ethanolic non-treated group. The protective group received WGO daily 1 h before ethanol administration. Serum (1.5 mL) from blood was extracted and examined for the changes in biochemical assessments in serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), bilirubin, serum γ-glutamyl transpeptidase (GGT), total protein, serum albumin, butyrylcholinesterase (BChE), total cholesterol (TC), total triglyceride (TG), urea, creatinine, uric acid, potassium (K⁺), Beta-2 microglobulin (β₂M), malondialdehyde (MDA), catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD) and aspartate aminotransferase (AST). Kidney and liver homogenate was used to measure MDA, GSH and catalase activities. Quantitative real time PCR (qRT-PCR) was used to express Nrf2 and HO-1 in liver, and NF-kB and kidney injury molecule (KIM-1) in kidneys, which are correlated with oxidative stress and inflammation. Capase-3 and Bcl2 genes were examined using immunohistochemical analysis in the kidney and liver. Ethanol administration induced significant alteration in examined liver and kidney markers (AST, ALT, GGT, ALP, total proteins, urea, creatinine and uric acid). Moreover, alcohol administration decreased antioxidant activities at serum and hepatorenal tissues (GSH, catalase and SOD), while MDA was increased as a tissue degradation marker. Inflammatory cytokines, together with genes of oxidative stress markers (Nrf2 and HO-1), were all affected. At cellular levels, apoptotic marker caspase-3 was upregulated, while antiapoptotic marker B-cell lymphoma 2 (Bcl2), was down regulated using immunohistochemical analysis. Of interest, pretreatment with WGO improved the side effects induced by ethanol on hepatic, renal biomarkers and reversed its impact on serum and tissue antioxidant parameters. Nrf2/HO-1 were upregulated, while NFk-B and KIM-1 were downregulated using real time PCR. Immune reactivities of caspase-3 and Bcl2 genes were restored in the protective group. In conclusion, WGO ameliorated ethanol-induced hepatic and renal dysfunction at the biochemical, molecular and cellular levels by regulating some mechanisms that controls oxidative stress, apoptosis, inflammation and anti-apoptotic pathways.

A review on garcinia kola heckel: traditional uses, phytochemistry, pharmacological activities, and toxicology

PURPOSE

Garcinia kola is a medicinal plant commonly known as bitter kola. It is utilised in ethnomedicine for the treatment of diarrhoea, bronchitis, bacterial infection, cough, hepatitis, gonorrhoea, laryngitis, food poison, liver and gastric diseases.

OBJECTIVE

This study reviewed the phytochemistry, pharmacological activities, and ethnomedicinal potentials of G. kola.

MATERIALS AND METHODS

An extensive review was performed using electronic literature collated from ScienceDirect, Springer, Wiley, and PubMed databases.

RESULTS

Phytochemical analysis revealed the isolation of several chemical compounds including 9-octadecenoic acid, linoleic acid, 14-methylpentadecanoic acid, 1-butanol, hexadecanamide, I-4',II-4',I-5,II-5,I-7,II-7-hexahydroxy-I-3,II-8-biflavanone, lanost-7-en-3-one, kolaflavanone (8E)-4-geranyl-3,5-dihydroxybenzophenone, glutinol, Garcinia biflavonoid (GB-2a-II-4'-OMe), 9,19-cyclolanost-24-en-3-ol, 24-methylene, tirucallol, lupeol, β-amyrin, obtusifoliol and Kolaviron. Diverse pharmacological in-vivo and in vitro investigations revealed that G. kola has anti-inflammatory, antimalarial, hepatoprotective, cardioprotective, anti-asthmatic, neuroprotective, antioxidant, and antidiabetic activities.

CONCLUSION

The present study revealed that G. kola has preventive and therapeutic potentials against various diseases in both in vivo and in vitro studies and therefore can be utilised as a raw material in the pharmaceutical industries for the development of therapeutic products. However, there is a need for clinical trial experiments to validate and provide accurate and substantial information on the required safe dosage and efficacy for the treatment of several diseases.

Adenosine Diphosphate and the P2Y13 Receptor Are Involved in the Autophagic Protection of Ex Vivo Perfused Livers From Fasted Rats: Potential Benefit for Liver Graft Preservation

Studies on how to protect livers perfused ex vivo can help design strategies for hepatoprotection and liver graft preservation. The protection of livers isolated from 24-hour versus 18-hour starved rats has been previously attributed to autophagy, which contributes to the energy-mobilizing capacity ex vivo. Here, we explored the signaling pathways responsible for this protection. In our experimental models, 3 major signaling candidates were considered in view of their abilities to trigger autophagy: high mobility group box 1 (HMGB1), adenosine monophosphate-activated protein kinase (AMPK), and purinergic receptor P2Y13. To this end, ex vivo livers isolated from starved rats were perfused for 135 minutes, after which perfusate samples were studied for protein release and biopsies were performed for evaluating signaling protein contents. For HMGB1, no significant difference was observed between livers isolated from rats starved for 18 and 24 hours at perfusion times of both 0 and 135 minutes. The phosphorylated and total forms of AMPK, but not their ratios, were significantly higher in 24-hour fasted than in 18-hour fasted livers. However, although the level of phosphorylated AMPK increased, perfusing ex vivo 18-hour fasted livers with 1 mM 5-aminoimidazole-4-carboxamide ribonucleotide, an AMPK activator, did not protect the livers. In addition, the adenosine diphosphate (ADP; and not adenosine monophosphate [AMP]) to AMP + ADP + adenosine triphosphate ratio increased in the 24-hour starved livers compared with that in the 18-hour starved livers. Moreover, perfusing 24-hour starved livers with 0.1 mM 2-[(2-chloro-5-nitrophenyl)azo]-5-hydroxy-6-methyl-3-[(phosphonooxy)methyl]-4-pyridinecarboxaldehyde (MRS2211), a specific antagonist of the P2Y13 receptor, induced an increase in cytolysis marker levels in the perfusate samples and a decrease in the levels of autophagic marker microtubule-associated proteins 1 light chain 3 II (LC3II)/actin (and a loss of p62/actin decrease), indicating autophagy inhibition and a loss of protection. The P2Y13 receptor and ADP (a physiological activator of this receptor) are involved in the protection of ex vivo livers. Therapeutic opportunities for improving liver graft preservation through the stimulation of the ADP/P2Y13 receptor axis are further discussed.

Hepatic and renal damage by alcohol and cigarette smoking in rats

Chronic use of alcohol and tobacco cigarettes is associated to millions of deaths per year, either by direct or indirect causes. However, few studies have explored the additional risks of the combined use of these drugs. Here we assessed the effect of the combined use of alcohol and cigarette smoke on liver or kidney morphology, and on biochemical parameters in chronically treated rats. Male Wistar rats were allocated to receive 2 g/kg alcohol orally, which was followed by the inhalation of smoke from six cigarettes during 2 h (ALTB group) for 28 days. Other groups received alcohol alone (AL) or were exposed to cigarette smoke (TB) alone and were compared to control (CT) rats, which received water followed by ambient air. On day 29, rats were euthanized and blood samples were collected for aminotransferase enzymes (AST and ALT), creatinine, and urea analysis. Liver and kidney were weighted, dissected, fixed, and stained with hematoxylin and eosin for morphological analysis. Our results showed that necrosis was elevated in the AL, TB, and mainly the ALTB group in both liver and kidney of rats. Serum levels of AST and ALT were reduced by cigarette smoke exposure, independently of alcohol use. Serum creatinine levels increased after tobacco smoke exposure. On the other hand, TB and AL groups decreased serum urea levels, and their association restored that decrease. Absolute liver and kidney weights were lower in the cigarette smoke exposure rats. Lastly, body weight gain was lower in TB group and combined use restored it. Thus, we may infer that the use of alcohol, exposure to tobacco cigarette smoke or, mainly, their association promotes liver and kidney injuries, and this damage is related with biochemical changes in rats.

Potential Benefits of N-Acetylcysteine in Preventing Pregabalin-Induced Seeking-Like Behavior

Substance-use disorder is globally prevalent and responsible for numerous social and medical problems. Pregabalin (Lyrica), typically used to treat diabetic neuropathy, has recently emerged as a drug of abuse. Drug abuse is associated with several neuronal changes, including the downregulation of glutamate transporters such as glutamate transporter 1 and cystine/glutamate antiporter. We investigated the effects of N-acetylcysteine, a glutamate transporter 1 and xCT upregulator, on pregabalin addiction using a conditioned place preference paradigm. Pregabalin (60 mg/kg) was found to induce conditioned place preference when compared to a vehicle. A 100 mg/kg dose of N-acetylcysteine was found to block pregabalin-seeking behaviors. These results support previous findings showing that glutamate transporters play an important role in pregabalin-induced seeking behaviors. N-acetylcysteine may represent a beneficial agent in preventing the abuse potential of pregabalin.

Changes in Glutathione Content in Liver Diseases: An Update

Glutathione (GSH), a tripeptide particularly concentrated in the liver, is the most important thiol reducing agent involved in the modulation of redox processes. It has also been demonstrated that GSH cannot be considered only as a mere free radical scavenger but that it takes part in the network governing the choice between survival, necrosis and apoptosis as well as in altering the function of signal transduction and transcription factor molecules. The purpose of the present review is to provide an overview on the molecular biology of the GSH system; therefore, GSH synthesis, metabolism and regulation will be reviewed. The multiple GSH functions will be described, as well as the importance of GSH compartmentalization into distinct subcellular pools and inter-organ transfer. Furthermore, we will highlight the close relationship existing between GSH content and the pathogenesis of liver disease, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), chronic cholestatic injury, ischemia/reperfusion damage, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatocellular carcinoma. Finally, the potential therapeutic benefits of GSH and GSH-related medications, will be described for each liver disorder taken into account.

Effects of N-acetylcysteine treatment on ethanol's rewarding properties and dopaminergic alterations in mesocorticolimbic and nigrostriatal pathways

Recent reports have shown that N-acetylcysteine (N-AC) has beneficial effects in the treatment of cocaine and nicotine abuse. Considering the similar neurobiologic mechanisms involved in the development of addiction to different drugs, N-AC treatment could be useful in the treatment of ethanol abuse. The rewarding properties of the drugs of abuse plays an important role in the development of addiction and can be studied using the conditioned place preference (CPP) paradigm. Thus, to study the effects of N-AC treatment in the rewarding effects of ethanol, we investigated the effects of N-AC administration in the ethanol-induced CPP and neurochemical alterations within the mesocorticolimbic and the nigrostriatal dopaminergic pathways. Adult male Swiss mice were pretreated with N-AC (60 or 120 mg/kg intraperitoneal) and tested for the development, expression, or extinction of the ethanol-induced CPP. Another cohort of animals received N-AC (60 or 120 mg/kg intraperitoneal) 2-h before an acute administration of ethanol and had their brains removed for dopamine and its metabolites quantification in the mesocorticolimbic and nigrostriatal pathways. Pretreatment with N-AC (120 mg/kg) blocked the development of ethanol-induced CPP. On the other hand, N-AC at both doses did not alter the expression nor the extinction of ethanol-induced CPP. N-AC increased 3,4-dihydroxyphenylacetic acid content in the medial prefrontal cortex and dopaminergic turnover within the substantia nigra. Besides that, there was an increase in dopamine content in the nucleus accumbens of ethanol-treated animals. In summary, N-AC treatment blocked the development of ethanol CPP, without altering ethanol effects on dopaminergic neurotransmission.

Oxidative Stress Parameters in the Liver of Growing Male Rats Receiving Various Alcoholic Beverages

Typical alcohol consumption begins in the adolescence period, increasing the risk of alcoholic liver disease (ALD) in adolescents and young adults, and while the pathophysiology of ALD is still not completely understood, it is believed that oxidative stress may be the major contributor that initiates and promotes the progression of liver damage. The aim of the present study was to assess the influence of alcohol consumption on the markers of oxidative stress and liver inflammation in the animal model of prolonged alcohol consumption in adolescents using various alcoholic beverages. In a homogenic group of 24 male Wistar rats (4 groups—6 animals per group), since 30th day of life, in order to mimic the alcohol consumption since adolescence, animals received (1) no alcoholic beverage (control group), (2) ethanol solution, (3) red wine, or (4) beer (experimental groups) for 6 weeks. Afterwards, the activities of alcohol dehydrogenase (ADH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), as well as levels of cytochrome P450-2E1 (CYP2E1), thiobarbituric acid-reactive substances (TBARS), protein carbonyl groups, tumor necrosis factor-α (TNF-α), and interleukine-10 (IL-10) were measured in liver homogenates. The difference between studied groups was observed for CYP2E1 and protein carbonyl groups levels (increased levels for animals receiving beer compared with control group), as well as for ALT activity (decreased activity for animals receiving beer compared with other experimental groups) (p < 0.05). The results suggested that some components of beer, other than ethanol, are responsible for its influence on the markers of oxidative stress and liver inflammation observed in the animal model of prolonged alcohol consumption in adolescents. Taking this into account, beer consumption in adolescents, which is a serious public health issue, should be assessed in further studies to broaden the knowledge of the progression of liver damage caused by alcohol consumption in this group.

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

Efficacy of Granulocyte Colony-Stimulating Factor and N-Acetylcysteine Therapies in Patients With Severe Alcoholic Hepatitis

BACKGROUND & AIMS

Patients with alcoholic hepatitis (AH) have high mortality, so new therapies are needed. Administration of granulocyte colony stimulating factor (G-CSF) increases survival times of patients with AH. It is not known whether addition of N-acetyl cysteine (NAC) to G-CSF could further increase survival time. We performed a randomized controlled pilot study to compare the efficacy of standard medical therapy with pentoxifylline to treatment with a combination of G-CSF and standard medical therapy as well as to the combination of NAC, G-CSF, and standard medical therapy in patients with severe AH.

METHODS

We performed an open-label, single-center study of 57 patients with severe AH admitted to a Liver Intensive Care unit in India from October 2014 through March 2017. Patients were randomly assigned to groups that received standard medical therapy (with pentoxifylline) plus G-CSF for 5 days (G-CSF group; n = 18), standard medical therapy plus G-CSF and intravenous NAC for 5 days (combination group; n = 19), or standard medical therapy alone (n = 20). Clinical data and blood samples were collected at baseline; on day 6; and 1, 2, and 3 months after the study began. CD34+ cells were measured in blood samples collected on days 0 and 6. The primary outcome was proportion of patients surviving for 90 days. Secondary outcomes were mobilization of CD34+ cells at day 6, as well as Child Turcotte Pugh, model for end-stage liver disease, and modified discriminant function scores until day 90.

RESULTS

Significantly higher proportions of patients in the G-CSF group (16/18) and the combination group (13/19) survived for 90 days than in the standard medical therapy group (6/20) (P = .0001 for G-CSF group and P = .037 and combination group). The GGSF and combination groups each had increased numbers of CD34+ cells from baseline until day 6, compared with the standard medical therapy group. The G-CSF group (but not the combination group) had significantly larger median reductions in modified discriminant function scores at study months 1 (reduction of 60.36%), 2 (reduction of 75.36%), and 3 (reduction of 88.73%) vs the standard medical therapy group (P = .02; P = .05; and P = .00, respectively). The G-CSF group had a significantly larger median reduction in model for end-stage liver disease score at 3 months (reduction of 55.77%; P = .01), but not in Child Turcotte Pugh score, compared with the standard medical therapy group. All groups had similar numbers of complications.

CONCLUSION

In a pilot randomized controlled trial, we found administration of G-CSF to improve liver function and increase survival times in patients with severe AH, compared with standard therapy. We found no evidence for benefit of adding NAC to G-CSF. These findings require confirmation in larger trials. ClincialTrials.gov, number: NCT02971306.

Effects of vitamin C and E on toxic action of alcohol on partial hepatectomy-induced liver regeneration in rats

The purpose of this study was to investigate the influence of vitamins C and E on the toxic action of alcohol in rat liver regeneration. Male Sprague-Dawley rats subjected to 70% partial hepatectomy were divided into five groups (Groups 1 to 5). Rats in Groups 2 to 5 were only provided alcohol for drinking. Additionally, vitamin C, vitamin E, and vitamin C in combination with vitamin E were administered to Groups 3, 4, and 5, respectively. Alcohol inhibits liver regeneration, resulting in an increase in free radicals produced by alcohol metabolism and thus causing cellular damage and altering liver function. During liver regeneration, vitamins C and E significantly ameliorated liver injury from alcohol administration by reducing hepatic lipid peroxidation. Vitamins C and E protect against liver injury and dysfunction, attenuate lipid peroxidation, and thus may be more effective in combination than either vitamin alone against alcohol-mediated toxic effects during liver regeneration.

Protective effect of carnosine and N-acetylcysteine against sodium nitrite-induced oxidative stress and DNA damage in rat intestine

The widespread use of sodium nitrite (NaNO₂) as food preservative, rampant use of nitrogenous fertilizers for agricultural practices, and improper disposal of nitrogenous wastes have drastically increased human exposure to high nitrite levels causing various health disorders and death. In the present study, the protective effect of carnosine and N-acetylcysteine (NAC) against NaNO₂-induced intestinal toxicity in rats was investigated. Animals were given a single acute oral dose of NaNO₂ at 60 mg/kg body weight with or without prior administration of either carnosine at 100 mg/kg body weight/day for 7 days or NAC at 100 mg/kg body weight/day for 5 days. Rats were killed after 24 h, and intestinal preparations were used for the evaluation of biochemical alterations and histological abrasions. Administration of NaNO₂ alone decreased the activities of intestinal brush border membrane and metabolic enzymes and significantly weakened the anti-oxidant defense system. DNA damage was also evident as observed by increased DNA-protein crosslinking and fragmentation. However, prior administration of carnosine or NAC significantly ameliorated NaNO₂-induced damage in intestinal cells. Histological studies support these biochemical results, showing intestinal damage in NaNO₂-treated animals and reduced tissue injury in the combination groups. The intrinsic anti-oxidant properties of carnosine and NAC must have contributed to the observed mitigation of nitrite-induced metabolic alterations and oxidative damage. Based on further validation from clinical trials, carnosine and NAC can potentially be used as chemo-preventive agents against NaNO₂ toxicity.

Antioxidant Effect of Barley Sprout Extract via Enhancement of Nuclear Factor-Erythroid 2 Related Factor 2 Activity and Glutathione Synthesis

We previously showed that barley sprout extract (BSE) prevents chronic alcohol intake-induced liver injury in mice. BSE notably inhibited glutathione (GSH) depletion and increased inflammatory responses, revealing its mechanism of preventing alcohol-induced liver injury. In the present study we investigated whether the antioxidant effect of BSE involves enhancing nuclear factor-erythroid 2 related factor 2 (Nrf2) activity and GSH synthesis to inhibit alcohol-induced oxidative liver injury. Mice fed alcohol for four weeks exhibited significantly increased oxidative stress, evidenced by increased malondialdehyde (MDA) level and 4-hydroxynonenal (4-HNE) immunostaining in the liver, whereas treatment with BSE (100 mg/kg) prevented these effects. Similarly, exposure to BSE (0.1–1 mg/mL) significantly reduced oxidative cell death induced by t-butyl hydroperoxide (t-BHP, 300 μM) and stabilized the mitochondrial membrane potential (∆ψ). BSE dose-dependently increased the activity of Nrf2, a potential transcriptional regulator of antioxidant genes, in HepG2 cells. Therefore, increased expression of its target genes, heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase catalytic subunit (GCLC) was observed. Since GCLC is involved in the rate-limiting step of GSH synthesis, BSE increased the GSH level and decreased both cysteine dioxygenase (CDO) expression and taurine level. Because cysteine is a substrate for both taurine and GSH synthesis, a decrease in CDO expression would further contribute to increased cysteine availability for GSH synthesis. In conclusion, BSE protected the liver cells from oxidative stress by activating Nrf2 and increasing GSH synthesis.

A Systems Approach Implicates a Brain Mitochondrial Oxidative Homeostasis Co-expression Network in Genetic Vulnerability to Alcohol Withdrawal

Genetic factors significantly affect vulnerability to alcohol dependence (alcoholism). We previously identified quantitative trait loci on distal mouse chromosome 1 with large effects on predisposition to alcohol physiological dependence and associated withdrawal following both chronic and acute alcohol exposure in mice (Alcdp1 and Alcw1, respectively). We fine-mapped these loci to a 1.1–1.7 Mb interval syntenic with human 1q23.2-23.3. Alcw1/Alcdp1 interval genes show remarkable genetic variation among mice derived from the C57BL/6J and DBA/2J strains, the two most widely studied genetic animal models for alcohol-related traits. Here, we report the creation of a novel recombinant Alcw1/Alcdp1 congenic model (R2) in which the Alcw1/Alcdp1 interval from a donor C57BL/6J strain is introgressed onto a uniform, inbred DBA/2J genetic background. As expected, R2 mice demonstrate significantly less severe alcohol withdrawal compared to wild-type littermates. Additionally, comparing R2 and background strain animals, as well as reciprocal congenic (R8) and appropriate background strain animals, we assessed Alcw1/Alcdp1 dependent brain gene expression using microarray and quantitative PCR analyses. To our knowledge this includes the first Weighted Gene Co-expression Network Analysis using reciprocal congenic models. Importantly, this allows detection of co-expression patterns limited to one or common to both genetic backgrounds with high or low predisposition to alcohol withdrawal severity. The gene expression patterns (modules) in common contain genes related to oxidative phosphorylation, building upon human and animal model studies that implicate involvement of oxidative phosphorylation in alcohol use disorders (AUDs). Finally, we demonstrate that administration of N-acetylcysteine, an FDA-approved antioxidant, significantly reduces symptoms of alcohol withdrawal (convulsions) in mice, thus validating a phenotypic role for this network. Taken together, these studies support the importance of mitochondrial oxidative homeostasis in alcohol withdrawal and identify this network as a valuable therapeutic target in human AUDs.

Hepatoprotective effects of hoveniae semen cum fructus extracts in ethanol intoxicated mice

[Purpose]

The objective of this study was to evaluate the hepatoprotective effects of Hoveniae Semen Cum Fructus extract in ethanol induced hepatic damages.

[Methods]

Hepatic damages were induced by oral administration of ethanol and then Hoveniae Semen Cum Fructus extract was administered.

[Results]

Following Hoveniae Semen Cum Fructus extract administration, body and liver weights were increased, while aspartate aminotransferase, alanine aminotransferase, albumin, γ-glutamyl transferase, and triglyceride levels in the serum, triglyceride contents, tumor necrosis factor -α level, cytochrome (CY) P450 2E1 activity in the liver and mRNA expression of hepatic lipogenic genes, and Nitrotyrosine and 4-HNE-immunolabelled hepatocytes were decreased. However, mRNA expression of genes involved in fatty acid oxidation was increased. Also, as a protective mechanism for hepatic antioxidant defense systems, decreased liver MDA contents, increased glutathione contents, increased dismutase and catalase activities were observed when compared to the ethanol control.

[Conclusion]

Hoveniae Semen Cum Fructus extract favorably protected against liver damages, mediated by its potent anti-inflammatory and anti-steatosis properties through the augmentation of the hepatic antioxidant defense system by NF-E2-related factor-2 activation, and down-regulation of the mRNA expression of hepatic lipogenic genes or up-regulation of the mRNA expression of genes involved in fatty acid oxidation.

Hepatoprotective Effects of Chinese Medicinal Herbs: A Focus on Anti-Inflammatory and Anti-Oxidative Activities

The liver is intimately connected to inflammation, which is the innate defense system of the body for removing harmful stimuli and participates in the hepatic wound-healing response. Sustained inflammation and the corresponding regenerative wound-healing response can induce the development of fibrosis, cirrhosis and eventually hepatocellular carcinoma. Oxidative stress is associated with the activation of inflammatory pathways, while chronic inflammation is found associated with some human cancers. Inflammation and cancer may be connected by the effect of the inflammation-fibrosis-cancer (IFC) axis. Chinese medicinal herbs display abilities in protecting the liver compared to conventional therapies, as many herbal medicines have been shown as effective anti-inflammatory and anti-oxidative agents. We review the relationship between oxidative stress and inflammation, the development of hepatic diseases, and the hepatoprotective effects of Chinese medicinal herbs via anti-inflammatory and anti-oxidative mechanisms. Moreover, several Chinese medicinal herbs and composite formulae, which have been commonly used for preventing and treating hepatic diseases, including Andrographis Herba, Glycyrrhizae Radix et Rhizoma, Ginseng Radix et Rhizoma, Lycii Fructus, Coptidis Rhizoma, curcumin, xiao-cha-hu-tang and shi-quan-da-bu-tang, were selected for reviewing their hepatoprotective effects with focus on their anti-oxidative and ant-inflammatory activities. This review aims to provide new insight into how Chinese medicinal herbs work in therapeutic strategies for liver diseases.

Molecular basis of alcoholic fatty liver disease: From incidence to treatment

Alcoholic liver diseases have complex and multiple pathogenic mechanisms but still no effective treatment. Steatosis or alcoholic fatty liver disease (AFLD) has a widespread incidence and is the first step in the progression to more severe stages of alcoholic liver disease, with concomitant increases in morbidity and mortality rates. The ways in which this progression occurs and why some individuals are susceptible are still unanswered scientific questions. Research with animal models and clinical evidence have shown that it is a multifactorial disease that involves interactions between lipid metabolism, inflammation, the immune response and oxidative stress. Each of these pathways provides a better understanding of the pathogenesis of AFLD and contributes to the development of therapeutic strategies. This review emphasizes the importance of research on alcoholic steatosis based on incidence data, key pathogenic mechanisms and therapeutic interventions, and discusses perspectives on the progression of this disease.

Zebrafish: an important tool for liver disease research

As the incidence of hepatobiliary diseases increases, we must improve our understanding of the molecular, cellular, and physiological factors that contribute to the pathogenesis of liver disease. Animal models help us identify disease mechanisms that might be targeted therapeutically. Zebrafish (Danio rerio) have traditionally been used to study embryonic development but are also important to the study of liver disease. Zebrafish embryos develop rapidly; all of their digestive organs are mature in larvae by 5 days of age. At this stage, they can develop hepatobiliary diseases caused by developmental defects or toxin- or ethanol-induced injury and manifest premalignant changes within weeks. Zebrafish are similar to humans in hepatic cellular composition, function, signaling, and response to injury as well as the cellular processes that mediate liver diseases. Genes are highly conserved between humans and zebrafish, making them a useful system to study the basic mechanisms of liver disease. We can perform genetic screens to identify novel genes involved in specific disease processes and chemical screens to identify pathways and compounds that act on specific processes. We review how studies of zebrafish have advanced our understanding of inherited and acquired liver diseases as well as liver cancer and regeneration.

Hepatoprotective activity of Peganum harmala against ethanol-induced liver damages in rats

In this study, we investigated the protective effects of Peganum harmala seeds extract (CPH) against chronic ethanol treatment. Hepatotoxicity was induced in male Wistar rats by administrating ethanol 35% (4 g/kg/day) for 6 weeks. CPH was co-administered with ethanol, by intraperitonial (IP) injection, at a dose of 10 mg/kg bw/day. Control rats were injected by saline solution (NaCl 9‰). Chronic ethanol administration intensified lipid peroxidation monitored by an increase of TBARS level in liver. Ethanol treatment caused also a drastic alteration in antioxidant defence system; hepatic superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. A co-administration of CPH during ethanol treatment inhibited lipid peroxidation and improved antioxidants activities. However, treatment with P. harmala extract protects efficiently the hepatic function of alcoholic rats by the considerable decrease of aminotransferase contents in serum of ethanol-treated rats.

Effect of Alocasia indica tuber extract on reducing hepatotoxicity and liver apoptosis in alcohol intoxicated rats

The possible protective role of ethanolic extract of A. indica tuber (EEAIT) in hepatotoxicity and apoptosis of liver caused by alcohol in rats was investigated. Treatment of rats with alcohol (3 g ethanol per kg body weight per day for 15 days intraperitoneally) produced marked elevation of liver biomarkers such as serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GT), and total bilirubin levels which were reduced by EEAIT in a dose-dependent manner. Furthermore, EEAIT improved antioxidant status (MDA, NO, and GSH) and preserved hepatic cell architecture. Simultaneous supplementation with EEAIT significantly restored hepatic catalase (CAT) and superoxide dismutase (SOD) activity levels towards normal. The studies with biochemical markers were strongly supported by the histopathological evaluation of the liver tissue. EEAIT also attenuated apoptosis and necrosis features of liver cell found in immunohistochemical evaluation. HPLC analysis of the extract showed the presence of three major peaks of which peak 2 (RT: 33.33 min) contains the highest area (%) and UV spectrum analysis identified it as flavonoids. It is therefore suggested that EEAIT can provide a definite protective effect against chronic hepatic injury caused by alcohol in rats, which may mainly be associated with its antioxidative effect.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

Red Mold Rice against Hepatic Inflammatory Damage in Zn-deficient Rats

The protective effect of red mold rice (RMR) against liver injury in rats fed with a Zn-deficient diet for 12 weeks was investigated in this study. Rats were orally administered RMR (151 mg/kg body weight or 755 mg/kg body weight; 1 × dose or 5 × dose, respectively) with or without Zn once a day for 4 consecutive weeks. The severity of liver damage was evaluated by measuring the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in Zn-deficient rats. RMR significantly inhibited the elevation of serum ALT levels by Zn-deficient induction. Hepatic antioxidase activity was also significantly increased in the RMR + Zn group (RZ), thereby suppressing the productions of reactive oxygen species (ROS) and proinflammatory cytokines in the liver of Zn-deficient rats. These findings suggested that RMR exerted hepatoprotective effects against Zn deficiency-induced liver inflammation.

Potential role of N-acetylcysteine in the management of substance use disorders

There is a clear and pressing need to expand pharmacotherapy options for substance use disorders (SUDs) in order to improve sustained abstinence outcomes. Preclinical literature has demonstrated the role of glutamate in addiction, suggesting that new targets for pharmacotherapy should focus on the restoration of glutamatergic function. Glutamatergic agents for SUDs may span multiple addictive behaviors and help demonstrate potentially overlapping mechanisms in addiction. The current review will focus specifically on N-acetylcysteine (NAC), a safe and well-tolerated glutamatergic agent, as a promising potential pharmacotherapy for the treatment of SUDs across several substances of abuse. Building on recently published reviews of the clinical efficacy of NAC across a broad range of conditions, this review will more specifically discuss NAC as a pharmacotherapy for SUDs, devoting particular attention to the safety and tolerability profile of NAC, the wealth of preclinical evidence that has demonstrated the role of glutamate dysregulation in addiction, and the limited but growing clinical literature that has assessed the efficacy of NAC across multiple substances of abuse. Preliminary clinical studies show the promise of NAC in terms of safety, tolerability, and potential efficacy for promoting abstinence from cocaine, nicotine, and cannabis. Results from randomized clinical trials have been mixed, but several mechanistic and methodological factors are discussed to refine the use of NAC in promoting abstinence and relapse prevention across several substances of abuse. Further preclinical and clinical investigation into the use of NAC for SUDs will be vital in addressing current deficits in the treatment of SUDs.

Biobreeding rat islets exhibit reduced antioxidative defense and N-acetyl cysteine treatment delays type 1 diabetes

Islet-level oxidative stress has been proposed as a trigger for type 1 diabetes (T1D), and release of cytokines by infiltrating immune cells further elevates reactive oxygen species (ROS), exacerbating β cell duress. To identify genes/mechanisms involved with diabetogenesis at the β cell level, gene expression profiling and targeted follow-up studies were used to investigate islet activity in the biobreeding (BB) rat. Forty-day-old spontaneously diabetic lymphopenic BB DRlyp/lyp rats (before T cell insulitis) as well as nondiabetic BB DR+/+ rats, nondiabetic but lymphopenic F344lyp/lyp rats, and healthy Fischer (F344) rats were examined. Gene expression profiles of BB rat islets were highly distinct from F344 islets and under-expressed numerous genes involved in ROS metabolism, including glutathione S-transferase (GST) family members (Gstm2, Gstm4, Gstm7, Gstt1, Gstp1, and Gstk1), superoxide dismutases (Sod2 and Sod3), peroxidases, and peroxiredoxins. This pattern of under-expression was not observed in brain, liver, or muscle. Compared with F344 rats, BB rat pancreata exhibited lower GST protein levels, while plasma GST activity was found significantly lower in BB rats. Systemic administration of the antioxidant N-acetyl cysteine to DRlyp/lyp rats altered abundances of peripheral eosinophils, reduced severity of insulitis, and significantly delayed but did not prevent diabetes onset. We find evidence of β cell dysfunction in BB rats independent of T1D progression, which includes lower expression of genes related to antioxidative defense mechanisms during the pre-onset period that may contribute to overall T1D susceptibility.

Inhibition of NF-κB activation by 4-hydroxynonenal contributes to liver injury in a mouse model of alcoholic liver disease

Long-term alcohol exposure sensitizes hepatocytes to tumor necrosis factor-α (TNF) cytotoxicity. 4-Hydroxynonenal (4-HNE) is one of the most abundant and reactive lipid peroxides. Increased hepatic 4-HNE contents present in both human alcoholics and alcohol-fed animals. In the present study, we investigated the effects of intracellular 4-HNE accumulation on TNF-induced hepatotoxicity and its potential implication in the pathogenesis of alcoholic liver disease. Male C57BL/6 mice were fed an ethanol-containing or a control diet for 5 weeks. Long-term alcohol exposure increased hepatic 4-HNE and TNF levels. Cell culture studies revealed that 4-HNE, at nontoxic concentrations, sensitized hepatocytes to TNF killing, which was associated with suppressed NF-κB transactivity. Further investigation demonstrated that 4-HNE prevented TNF-induced inhibitor of κBα phosphorylation without affecting upstream IκB kinase activity. An immunoprecipitation assay revealed that increased 4-HNE content was associated with increased formation of 4-HNE-inhibitor of κBα adduction in both 4-HNE-treated hepatocytes and in the livers of alcohol-fed mice. Prevention of intracellular 4-HNE accumulation by bezafibrate, a peroxisome proliferator-activated receptor-α agonist, protected hepatocytes from TNF killing via NF-κB activation. Supplementation of N-acetylcysteine, a glutathione precursor, conferred a protective effect on alcohol-induced liver injury in mice, was associated with decreased hepatic 4-HNE formation, and improved hepatic NF-κB activity. In conclusion, increased 4-HNE accumulation represents a potent and clinically relevant sensitizer to TNF-induced hepatotoxicity. These data support the notion that removal of intracellular 4-HNE can serve as a potential therapeutic option for alcoholic liver disease.

Protective effects of aqueous extract of Hammada scoparia against hepatotoxicity induced by ethanol in the rat

Aqueous extract (AE) of Hammada scoparia leaves was chemically characterized and its hepatoprotective activities were investigated in vivo in rat model. Wistar rats were treated daily with 35% ethanol solution (3 g/kg/day) during 4 weeks and fed with basal diet or basal diet containing AE (200 mg/kg/day). Control rats were treated with saline solution and fed with basal diet. The bioactivity of AE against ethanol-induced oxidative stress in rat liver was studied in order to explore its hepatoprotective effects. H. scoparia extract used at 200 mg/kg body weight significantly prevented the effects of ethanol, which induced a hepatic pathological damage and increased the levels of the serum markers of the enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP). Concomitantly, with these changes, this extract also prevented ethanol-induced oxidative stress in the rat liver as evidenced by the decreased lipid peroxidation level, a considerable decrease in the activities of AST, ALT and ALP and restoring the activities of antioxidant enzymes: superoxide dismutase, catalase and glutathione peroxidase. These biochemical changes were consistent with histopathological observations suggesting marked hepatoprotective effect of the AE of H. scoparia.

Oxidative Stress and the ER Stress Response in a Murine Model for Early-Stage Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a primary cause of morbidity and mortality in the United States and constitutes a significant socioeconomic burden. Previous work has implicated oxidative stress and endoplasmic reticulum (ER) stress in the etiology of ALD; however, the complex and interrelated nature of these cellular responses presently confounds our understanding of ethanol-induced hepatopathy. In this paper, we assessed the pathological contribution of oxidative stress and ER stress in a time-course mouse model of early-stage ALD. Ethanol-treated mice exhibited significant hepatic panlobular steatosis and elevated plasma ALT values compared to isocaloric controls. Oxidative stress was observed in the ethanol-treated animals through a significant increase in hepatic TBARS and immunohistochemical staining of 4-HNE-modified proteins. Hepatic glutathione (GSH) levels were significantly decreased as a consequence of decreased CBS activity, increased GSH utilization, and increased protein glutathionylation. At the same time, immunoblot analysis of the PERK, IRE1α, ATF6, and SREBP pathways reveals no significant role for these UPR pathways in the etiology of hepatic steatosis associated with early-stage ALD. Collectively, our results indicate a primary pathogenic role for oxidative stress in the early initiating stages of ALD that precedes the involvement of the ER stress response.

Glucocorticoids plus N-acetylcysteine in severe alcoholic hepatitis

BACKGROUND

Mortality among patients with severe acute alcoholic hepatitis is high, even among those treated with glucocorticoids. We investigated whether combination therapy with glucocorticoids plus N-acetylcysteine would improve survival.

METHODS

We randomly assigned 174 patients to receive prednisolone plus N-acetylcysteine (85 patients) or only prednisolone (89 patients). All patients received 4 weeks of prednisolone. The prednisolone-N-acetylcysteine group received intravenous N-acetylcysteine on day 1 (at a dose of 150, 50, and 100 mg per kilogram of body weight in 250, 500, and 1000 ml of 5% glucose solution over a period of 30 minutes, 4 hours, and 16 hours, respectively) and on days 2 through 5 (100 mg per kilogram per day in 1000 ml of 5% glucose solution). The prednisolone-only group received an infusion in 1000 ml of 5% glucose solution per day on days 1 through 5. The primary outcome was 6-month survival. Secondary outcomes included survival at 1 and 3 months, hepatitis complications, adverse events related to N-acetylcysteine use, and changes in bilirubin levels on days 7 and 14.

RESULTS

Mortality was not significantly lower in the prednisolone-N-acetylcysteine group than in the prednisolone-only group at 6 months (27% vs. 38%, P = 0.07). Mortality was significantly lower at 1 month (8% vs. 24%, P = 0.006) but not at 3 months (22% vs. 34%, P = 0.06). Death due to the hepatorenal syndrome was less frequent in the prednisolone-N-acetylcysteine group than in the prednisolone-only group at 6 months (9% vs. 22%, P = 0.02). In a multivariate analysis, factors associated with 6-month survival were a younger age (P<0.001), a shorter prothrombin time (P<0.001), a lower level of bilirubin at baseline (P<0.001), and a decrease in bilirubin on day 14 (P<0.001). Infections were less frequent in the prednisolone-N-acetylcysteine group than in the prednisolone-only group (P = 0.001); other side effects were similar in the two groups.

CONCLUSIONS

Although combination therapy with prednisolone plus N-acetylcysteine increased 1-month survival among patients with severe acute alcoholic hepatitis, 6-month survival, the primary outcome, was not improved. (Funded by Programme Hospitalier de Recherche Clinique; AAH-NAC ClinicalTrials.gov number, NCT00863785 .).

Neuroprotective effects of the 17β-estradiol against ethanol-induced neurotoxicity and oxidative stress in the developing male rat cerebellum: biochemical, histological and behavioral changes

During particular periods of central nervous system (CNS) development, exposure to ethanol can decrease regional brain growth and can result in selective loss of neurons. Unfortunately, there are few effective means of attenuating damage in the immature brain. In this study, the possible antioxidant and neuroprotective properties of 17β-estradiol against ethanol-induced neurotoxicity was investigated. 17β-estradiol (600 μg/kg) was injected subcutaneously in postnatal day (PD) 4 and 5, 30 min prior to intraperitoneal injection of ethanol (6g/kg) in rat pups. Ninety minutes after injection of ethanol, the activities of several antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (Gpx) in vermis of cerebellum were assayed. Thiobarbituric acid reactive substance (TBARS) levels were also measured as a marker of lipid peroxidation. Behavioral studies, including rotarod and locomotor activity tests were performed in PD 21-23 and histological study was performed after completion of behavioral measurements in postnatal day 23. The results of the present work demonstrated that ethanol could induce lipid peroxidation, increase TBARS levels and decrease glutathione peroxidase levels in pup cerebellum. We also observed that ethanol impaired performance on the rotarod and locomotor activities of rat pups. However, treatment with 17β-estradiol significantly attenuated motoric impairment, the lipid peroxidation process and restored the levels of antioxidants. Histological analysis also indicated that ethanol could decrease vermis Purkinje cell count and 17β-estradiol prevented this toxic effect. These results suggest that ethanol may induce lipid peroxidation in the rat pups cerebellum while treatment with 17β-estradiol improves motor deficits by protecting the cerebellum against ethanol toxicity.

Catechin suppresses an array of signalling molecules and modulates alcohol-induced endotoxin mediated liver injury in a rat model

Induction of nuclear factor kappa B (NF-κB)-mediated gene expression has been implicated in the pathogenesis of alcoholic liver disease through enhanced production of reactive oxygen species and pro-inflammatory mediators. The present study was carried out to investigate the role of catechin as a chain breaking inhibitor against experimental alcoholic liver injury. Rats were administered 35% v/v ethanol orally at a dose of 10 g/Kg/day for two weeks, followed by 14 g/Kg/day for 10 weeks. Catechin (50 mg/Kg) was co-supplemented after 4 weeks of alcohol treatment till the end of the dosing period. Following chronic alcohol exposure, rats developed endotoxemia and severe pathological changes in the liver such as pronounced fatty change, vacuolar degeneration and inflammation. These changes were accompanied by activation of NF-κB and induction of inflammatory and cytotoxic mediators leading to increased level of tumor necrosis factor-alpha, enhanced formation of malondialdehyde in the liver followed by drastic alterations in the hepatic antioxidant defense systems. Additionally, nitrite levels and lactate dehydrogenase activities were also significantly elevated on chronic alcohol consumption. Alcohol exposure also increased the number of micronucleated cells indicating that alcohol abuse may again be associated with the nuclear changes. Supplementation with catechin ameliorated the alcohol-induced liver injury by downregulating the endotoxin-mediated activation of initial signalling molecule NF-κB and further going downstream the signalling cascade including tumor necrosis factor-alpha, nitric oxide and reactive oxygen species and by enhancing the antioxidant profile. These observations correlated well with the histological findings. Moreover, a remarkable decrease in the percentage of micronucleated cells was observed with catechin supplementation indicating an apparent protection against alcohol-induced toxicity. These findings suggest that catechin may alleviate experimental alcoholic liver disease by suppressing induction of NF-κB, a key component of signalling pathway, thus forming a pharmacological basis for designing novel therapeutic agents against alcohol induced endotoxin-mediated liver injury.

Influence of N-acetylcysteine against dimethylnitrosamine induced hepatotoxicity in rats

This study evaluates the hepatoprotective and antioxidant properties of N-acetylcysteine (NAC) on dimethylnitrosamine (DMN) induced hepatotoxicity in male Wistar albino rats. A single intraperitoneal dose of DMN (5 mg/kg b.w.) caused a significant increase in the levels of the serum marker enzymes (aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), glutamyl transpeptidase (γ-GT)) and a subsequent decrease in AST, ALT, ALP and increase in LDH and γ-GT in the liver tissue indicating hepatocellular damage. Elevation in the status of lipid peroxidation, fall in the activities of the enzymic (superoxide dismutase, catalase) and non-enzymic antioxidants (vitamin C, vitamin E) in the liver tissue further confirms oxidative stress and hepatocellular damage induced on DMN administration. Oral administration of NAC (50 mg/kg b.w.) for 7 days significantly prevented the above alterations in the status of the marker enzymes of hepatotoxicity and antioxidant parameters and restored them towards normalcy, which was further substantiated by the histopathological studies of the liver tissue. These results suggest that NAC offers hepatoprotection by ameliorating DMN-induced oxidative stress and hepatotoxicity and this protective effect was attributed to its antioxidant and free radical scavenging properties.

Protective effect of trapidil and l-arginine against renal and hepatic toxicity induced by cyclosporine in rats

RATIONALE

Cyclosporine A (CsA) leads to renal and liver injury, production of free radicals and nitric oxide (NO) deficiency. This study investigates the possible protective effects of trapidil and L-arginine against CsA-induced tissue injury.

OBJECTIVES

Forty adult male Wistar rats (180 +/- 20 g) were divided into five groups, eight animals in each. The first group served as control, second group served as CsA group, third group served as CsA + trapidil group, fourth group served as CsA + L-arginine group, and fifth group served as CsA + trapidil + L-arginine group. Kidney and liver functions, inflammatory mediators, cytokines, oxidant and antioxidant parameters as well as histopathological studies of renal and liver tissue were assessed in all groups.

MAIN FINDINGS

CsA induced renal and hepatic dysfunction, which was confirmed by laboratory and histopathological examination. Administration of trapidil diminished the renal and liver injury and significantly attenuated the levels of serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), and oxidative stress, while it significantly elevated the level of serum nitric oxide and the activity of antioxidative stress. L-Arginine gave the same trend as trapidil, but trapidil effect was more pronounced. Coadministration of trapidil + L-arginine significantly ameliorated the toxic effect of CsA, but did not differ significantly from the effect of trapidil alone.

CONCLUSIONS

Treatment with trapidil or L-arginine diminished the renal and hepatic CsA-induced toxicity. However, the effect of trapidil was more pronounced. Therefore, treatment with trapidil alone may be the most economic and effective as a potential therapeutic agent in CsA injury.

N-acetylcysteine attenuates dimethylnitrosamine induced oxidative stress in rats

Oxidative stress has been implicated in the pathogenesis and progression of various hepatic disorders and hence screening for a good hepatoprotective and antioxidant agent is the need of the hour. The present study was aimed to investigate the hepatoprotective and antioxidant property of N-acetylcysteine (NAC) against dimethylnitrosamine (DMN) induced oxidative stress and hepatocellular damage in male Wistar albino rats. Administration of single dose of DMN (5mg/kg b.w.; i.p.) resulted in significant elevation in the levels of serum aspartate transaminase and alanine transaminase, indicating hepatocellular damage. Oxidative stress induced by DMN treatment was confirmed by an elevation in the status of lipid peroxidation (LPO) and reduction in the activities of enzymic antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase and in the levels of non-enzymic antioxidants, reduced glutathione, vitamin-C and vitamin-E in the liver tissue. DMN induced oxidative stress and hepatocellular membrane instability was further substantiated by a decline in the status of the membrane bound ATPases in the liver tissue. Post-treatment with NAC (50mg/kg b.w.; p.o.) for 7days effectively protected against the DMN induced insult to liver by preventing the elevation in the status of the serum marker enzymes and LPO, and restoring the activities of both the enzymic and non-enzymic antioxidants and membrane bound ATPases towards normalcy. These results demonstrate that NAC acts as a good hepatoprotective and antioxidant agent in attenuating DMN induced oxidative stress and hepatocellular damage.

Long-term alcohol consumption increases pro-matrix metalloproteinase-9 levels via oxidative stress

Matrix metalloproteinases (MMPs) play an important role in alcoholic liver disease. In this study, we evaluated the relationship between pro MMP-9 (pMMP-9) and oxidative stress in plasma of rat exposed to chronic alcohol consumption. Twenty four rats were divided into four groups. Rats in the control group (n = 6) were subjected to physiologic saline by intragastric (i.g.) route. Group Ethanol (n = 6) was given 1 ml of 80% ethanol (v/v) in distilled water through i.g. route. Group Vitamin E (Vit E), (n = 6) was given vitamin E (100 mg kg⁻¹ day⁻¹) by intra peritonealy. Group Vitamin E + Ethanol (n = 6) was given vitamin E 2 h before the administration of ethanol. At the end of 4 weeks, blood samples were taken and plasma malondialdehyde (MDA), protein carbonyls (PCs), aspartate aminotransferase (AST), tumor necrosis factor-α (TNF-α) and pMMP-9 levels were measured. Chronic ethanol administration increased the AST, MDA, PCs, TNF-α and pMMP-9 levels when compared to those in control group (p < 0.05, p < 0.01, p < 0.01, p < 0.05, p < 0.05, respectively). Vitamin E treatment was found to decrease lipid peroxidation and protein oxidation (p < 0.01, p < 0.01, respectively). Also TNF-α and pMMP-9 levels returned to normal by vitamin E treatment. Within all subjects, there was positive correlation between pMMP-9 levels and MDA, PCs levels (p = 0.045, r = 0.454; p = 0.004, r = 0.574, respectively). We conclude that since antioxidant supplementation decreases the alcohol-induced pMMP-9 levels, oxidative stress could be one of the mediators of the generation of MMP-9.

Effect of Pelargonium reniforme roots on alcohol-induced liver damage and oxidative stress

CONTEXT

Ethnobotanical surveys conducted on Pelargonium reniforme Curtis (Geraniaceae) have shown that the aqueous root extracts are used to treat alcohol-induced liver damage.

OBJECTIVE

We evaluated the antioxidant properties of the extract and its effects on alcohol-induced hepatotoxicity using Wistar rats.

MATERIALS AND METHODS

Alcohol-induced hepatotoxicity studies were carried out by observing the effect of the aqueous root extract on some liver marker enzymes, bilirubin, and total protein after liver damage. The levels of some phenolic compounds were determined by standard methods. Also, the reducing power of the plant extract and its ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH*) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS*+) radicals were determined to evaluate its antioxidant activity.

RESULTS AND DISCUSSION

The results obtained show that the plant extract possessed significant antioxidant activity. It had a significant level of phenolic compounds, scavenged DPPH* and ABTS*+ radicals effectively, and demonstrated good reducing power. This may indicate that the plant contained compounds which can remove toxic metabolites following alcohol abuse. Serum analysis of animals treated with only ethanol showed a significant increase in the levels of liver marker enzymes and total and unconjugated bilirubin, while a significant decrease was observed in the levels of conjugated bilirubin and total proteins. Administration of the plant extract restored the levels of these markers to normal levels, and this indicates the ability of the plant extract to restore normal functioning of a damaged liver.

CONCLUSION

The study shows that P. reniforme is a potential source of antioxidants and compounds which are useful in treating alcoholic liver damage.