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Rasouli H, Razavi BM, Ghasemzadeh Rahbardar M, Sadeghian H, Tabatabaee Yazdi SA, Hosseinzadeh H. Hepatoprotective effect of amifostine and WR-1065 on acetaminophen-induced liver toxicity on Wistar rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-03000-2. [PMID: 38381146 DOI: 10.1007/s00210-024-03000-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 02/05/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE The most important problem with acetaminophen is its hepatotoxicity. N-acetylcysteine (NAC) is used to treat the hepatotoxicity of acetaminophen. Due to the structural similarities of this compound with amifostine, we decided to test the effect of this substance and its metabolite, WR-1065, on the hepatotoxicity of acetaminophen. METHODS The single-dose method contained 1. Control; 2. Acetaminophen (1 g/kg, gavage); 3-5. Acetaminophen + amifostine (100, 200, 400 mg/kg, i.p.); 6-8. Acetaminophen + WR-1065 (50, 100, 200 mg/kg, i.p.); and 9. Acetaminophen + NAC (100, 200 mg/kg, i.p.). The multiple-dose method included the same groups: amifostine (50, 100, 200 mg/kg), WR-1065 (25, 50, 100 mg/kg), and NAC (100 mg/kg). Then, animals were sacrificed, and blood samples were collected for measuring ALT, AST, ALP, and T-Bil, liver tissue for histopathological examination, MDA, and GSH amounts. RESULTS Acetaminophen increased the levels of MDA, T-Bil, ALT, AST, and ALP, decreased GSH levels, and augmented necrosis, neutrophils, lymphocytes, and macrophages in the port space in single-dose and multiple-dose studies. Amifostine and WR-1065 significantly reduced the levels of MDA, T-Bil, ALT, AST, ALP, increased GSH content, and ameliorated histopathological alterations in a single-dose and multiple-dose method compared to the acetaminophen group. Moreover, NAC caused a significant decrease in the levels of MDA, T-Bil, ALT, AST, and ALP, and reduced GSH amounts in single-dose and multiple-dose studies. CONCLUSION Amifostine and WR-1065 as antioxidant and hepatoprotective compounds are effective in reducing acetaminophen-induced hepatotoxicity with a similar effect to NAC and can be administered as an adjunct in the treatment of acetaminophen overdose.
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Affiliation(s)
- Hashem Rasouli
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Bibi Marjan Razavi
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Hamid Sadeghian
- Department of Laboratory Sciences, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Hossein Hosseinzadeh
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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Sandoval C, Farías J, Zamorano M, Herrera C. Vitamin Supplements as a Nutritional Strategy against Chronic Alcohol Consumption? An Updated Review. Antioxidants (Basel) 2022; 11:antiox11030564. [PMID: 35326214 PMCID: PMC8945215 DOI: 10.3390/antiox11030564] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/12/2022] [Accepted: 03/12/2022] [Indexed: 02/07/2023] Open
Abstract
Several studies have shown that blood vitamin levels are low in alcoholic patients. In effect, alcohol use abuse is considered a chronic disease that promotes the pathogenesis of many fatal diseases, such as cancer and liver cirrhosis. The alcohol effects in the liver can be prevented by antioxidant mechanisms, which induces enzymatic as well as other nonenzymatic pathways. The effectiveness of several antioxidants has been evaluated. However, these studies have been accompanied by uncertainty as mixed results were reported. Thus, the aim of the present review article was to examine the current knowledge on vitamin deficiency and its role in chronic liver disease. Our review found that deficiencies in nutritional vitamins could develop rapidly during chronic liver disease due to diminished hepatic storage and that inadequate vitamins intake and alcohol consumption may interact to deplete vitamin levels. Numerous studies have described that vitamin supplementation could reduce hepatotoxicity. However, further studies with reference to the changes in vitamin status and the nutritional management of chronic liver disease are in demand.
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Affiliation(s)
- Cristian Sandoval
- Escuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomás, Los Carreras 753, Osorno 5310431, Chile
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Temuco 4811230, Chile; (J.F.); (M.Z.)
- Departamento de Ciencias Preclínicas, Facultad de Medicina, Universidad de La Frontera, Temuco 4811230, Chile;
- Correspondence: ; Tel.: +56-45-2325720
| | - Jorge Farías
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Temuco 4811230, Chile; (J.F.); (M.Z.)
- Núcleo Científico y Tecnológico en Biorecursos (BIOREN), Universidad de La Frontera, Temuco 4811230, Chile
| | - Mauricio Zamorano
- Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Temuco 4811230, Chile; (J.F.); (M.Z.)
- Núcleo Científico y Tecnológico en Biorecursos (BIOREN), Universidad de La Frontera, Temuco 4811230, Chile
| | - Christian Herrera
- Departamento de Ciencias Preclínicas, Facultad de Medicina, Universidad de La Frontera, Temuco 4811230, Chile;
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Yi HW, Zhu XX, Huang XL, Lai YZ, Tang Y. Selenium-enriched Bifidobacterium longum protected alcohol and high fat diet induced hepatic injury in mice. Chin J Nat Med 2020; 18:169-177. [PMID: 32245586 DOI: 10.1016/s1875-5364(20)30018-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Indexed: 12/12/2022]
Abstract
The objective of this study was to verify the protective effect of Bifidobacterium longum (BL) and the synergistical effect of Selenium and BL on alcohol plus high fat diet (HFD) induced hepatic injury in mice. We also want to explore the mechanism of Selenium-enriched Bifidobacterium longum (SeBL). C57BL/6 mice were treated with alcohol plus HFD with or without different dosage of BL or SeBL for 4 weeks. Serum levels of ALT, AST, TC, TG, LDL-C, HDL-C, FFAs, TNF-α, IL-6 and IL-1β, hepatic MDA level, SOD activity, the mRNA levels of AMPK, PPAR-α and SREBP1 were invested. SeBL inhibited lipid accumulation in hepatocytes; reduced serum AST and ALT levels; improved dyslipidemia; decreased serum FFAs, TC, TG and LDL-C levels. SeBL also inhibited alcohol plus HFD-induced hepatocyte oxidative stress through decrease in hepatic MDA levels and increase in SOD activity. SeBL also regulated lipid metabolism related genes such as AMPK, PPAR-α and SREBP1. Although BL had similar effect as SeBL, SeBL is more effective than BL. SeBL protected mice from alcohol plus HFD-induced hepatic injury in mice because of its inhibitory effect on hepatocellular oxidative stress, lipogenesis and inflammation. Selenium enhanced the protective effect of BL.
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Affiliation(s)
- Hong-Wei Yi
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China.
| | - Xiao-Xiao Zhu
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China.
| | - Xiao-Li Huang
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China.
| | - Yu-Zhu Lai
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China.
| | - Yue Tang
- Department of Pharmacology, School of Medicine, Southeast University, Nanjing 210009, China.
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Tu Y, Zhu S, Wang J, Burstein E, Jia D. Natural compounds in the chemoprevention of alcoholic liver disease. Phytother Res 2019; 33:2192-2212. [PMID: 31264302 DOI: 10.1002/ptr.6410] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 04/29/2019] [Accepted: 05/21/2019] [Indexed: 12/17/2022]
Abstract
Alcoholic liver disease (ALD), caused by excessive consumption of alcohol, is a major cause of chronic liver disease worldwide. Much effort has been expended to explore the pathogenesis of ALD. Hepatic cell injury, oxidative stress, inflammation, regeneration, and bacterial translocation are all involved in the pathogenesis of ALD. Immediate abstinence is the most important therapeutic treatment for affected individuals. However, the medical treatment for ALD had not advanced in a long period. Intriguingly, an increasing body of research indicates the potential of natural compounds in the targeted therapy of ALD. A plethora of dietary natural products such as flavonoids, resveratrol, saponins, and β-carotene are found to exert protective effects on ALD. This occurs through various mechanisms composed of antioxidative, anti-inflammatory, iron chelation, pro-apoptosis, and/or antiproliferation of hepatic stellate cells and hepatocellular carcinoma cells. In this review, we will summarize current knowledge about the pathogenesis and treatments of ALD and focus on the potential of natural compounds in ALD therapies and underlying mechanisms.
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Affiliation(s)
- Yingfeng Tu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Shu Zhu
- Chinese Academy of Science and Technology for Development, Ministry of Science and Technology, Institute of Foresight and Evaluation Research, Beijing, China
| | - Jing Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Ezra Burstein
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
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Ali H, Assiri MA, Shearn CT, Fritz KS. Lipid peroxidation derived reactive aldehydes in alcoholic liver disease. CURRENT OPINION IN TOXICOLOGY 2018; 13:110-117. [PMID: 31263795 DOI: 10.1016/j.cotox.2018.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipid peroxidation is a known consequence of oxidative stress and is thought to play a key role in numerous disease pathologies, including alcoholic liver disease (ALD). The overaccumulation of lipid peroxidation products during chronic alcohol consumption results in pathogenic lesions on protein, DNA, and lipids throughout the cell. Molecular adducts due to secondary end products of lipid peroxidation impact a host of biochemical processes, including inflammation, antioxidant defense, and metabolism. The aggregate burden of lipid peroxidation which occurs due to chronic alcohol metabolism, including downstream signaling events, contributes to the development and progression of ALD. In this current opinion we highlight recent studies and approaches relating cellular mechanisms of lipid peroxidation to the pathogenesis of alcoholic liver disease.
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Affiliation(s)
- Hadi Ali
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Mohammed A Assiri
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Colin T Shearn
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Kristofer S Fritz
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
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Kannan M, Wang L, Kang YJ. Myocardial Oxidative Stress and Toxicity Induced by Acute Ethanol Exposure in Mice. Exp Biol Med (Maywood) 2016; 229:553-9. [PMID: 15169975 DOI: 10.1177/153537020422900614] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Alcoholic cardiomyopathy has been known for a long time, but there is little mechanistic insight into this important clinical problem. The present study was undertaken using a mouse model to test the hypothesis that alcohol exposure induces cardiac injury through induction of oxidative stress. Adult female Friend Virius B-type (FVB) mice were treated with ethanol by gavage at a dose of 5 g/kg. Six hours after the treatment, ethanol-induced myocardial injury was observed, as indicated by a significant increase in serum creatine phosphokinase activity, a common biomarker of myocardial injury, and myocardial ultrastructural alterations, predominantly mitochondrial swelling and cristae disarray and reduction in numbers. The myocardial injury was associated with a significant increase in the myocardial lipid peroxidation, determined by measuring thiobarbituric acid reactive substances (TBARS), and a significant increase in protein oxidation as measured by a protein carbonyl content assay. Acute alcohol exposure decreased glutathione (GSH) content in the heart, more so in the mitochondria than in the cytosol. These alcohol-induced myocardial injuries and oxidative stresses were all significantly inhibited by supplementation with N-acetyl-L-cysteine (NAC) prior to alcohol exposure. However, NAC did not affect the rise in blood alcohol concentrations following alcohol exposure. This study thus demonstrates that acute alcohol administration causes myocardial injury through, at least in part, the induction of oxidative stress. A rapid decrease in mitochondrial GSH content may be partially responsible for the observed mitochondrial damage.
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Affiliation(s)
- Muralidhar Kannan
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Kentucky 40202,USA
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Chronic Glutathione Depletion Confers Protection against Alcohol-induced Steatosis: Implication for Redox Activation of AMP-activated Protein Kinase Pathway. Sci Rep 2016; 6:29743. [PMID: 27403993 PMCID: PMC4940737 DOI: 10.1038/srep29743] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/22/2016] [Indexed: 12/19/2022] Open
Abstract
The pathogenesis of alcoholic liver disease (ALD) is not well established. However, oxidative stress and associated decreases in levels of glutathione (GSH) are known to play a central role in ALD. The present study examines the effect of GSH deficiency on alcohol-induced liver steatosis in Gclm knockout (KO) mice that constitutively have ≈15% normal hepatic levels of GSH. Following chronic (6 week) feeding with an ethanol-containing liquid diet, the Gclm KO mice were unexpectedly found to be protected against steatosis despite showing increased oxidative stress (as reflected in elevated levels of CYP2E1 and protein carbonyls). Gclm KO mice also exhibit constitutive activation of liver AMP-activated protein kinase (AMPK) pathway and nuclear factor-erythroid 2–related factor 2 target genes, and show enhanced ethanol clearance, altered hepatic lipid profiles in favor of increased levels of polyunsaturated fatty acids and concordant changes in expression of genes associated with lipogenesis and fatty acid oxidation. In summary, our data implicate a novel mechanism protecting against liver steatosis via an oxidative stress adaptive response that activates the AMPK pathway. We propose redox activation of the AMPK may represent a new therapeutic strategy for preventing ALD.
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Oxidative Stress in the Healthy and Wounded Hepatocyte: A Cellular Organelles Perspective. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:8327410. [PMID: 26788252 PMCID: PMC4691634 DOI: 10.1155/2016/8327410] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 09/10/2015] [Indexed: 02/06/2023]
Abstract
Accurate control of the cell redox state is mandatory for maintaining the structural integrity and physiological functions. This control is achieved both by a fine-tuned balance between prooxidant and anti-oxidant molecules and by spatial and temporal confinement of the oxidative species. The diverse cellular compartments each, although structurally and functionally related, actively maintain their own redox balance, which is necessary to fulfill specialized tasks. Many fundamental cellular processes such as insulin signaling, cell proliferation and differentiation and cell migration and adhesion, rely on localized changes in the redox state of signal transducers, which is mainly mediated by hydrogen peroxide (H2O2). Therefore, oxidative stress can also occur long before direct structural damage to cellular components, by disruption of the redox circuits that regulate the cellular organelles homeostasis. The hepatocyte is a systemic hub integrating the whole body metabolic demand, iron homeostasis and detoxification processes, all of which are redox-regulated processes. Imbalance of the hepatocyte's organelles redox homeostasis underlies virtually any liver disease and is a field of intense research activity. This review recapitulates the evolving concept of oxidative stress in the diverse cellular compartments, highlighting the principle mechanisms of oxidative stress occurring in the healthy and wounded hepatocyte.
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Abstract
Alcoholic liver disease (ALD) is a complex process that includes a wide spectrum of hepatic lesions, from steatosis to cirrhosis. Cell injury, inflammation, oxidative stress, regeneration and bacterial translocation are key drivers of alcohol-induced liver injury. Alcoholic hepatitis is the most severe form of all the alcohol-induced liver lesions. Animal models of ALD mainly involve mild liver damage (that is, steatosis and moderate inflammation), whereas severe alcoholic hepatitis in humans occurs in the setting of cirrhosis and is associated with severe liver failure. For this reason, translational studies using humans and human samples are crucial for the development of new therapeutic strategies. Although multiple attempts have been made to improve patient outcome, the treatment of alcoholic hepatitis is still based on abstinence from alcohol and brief exposure to corticosteroids. However, nearly 40% of patients with the most severe forms of alcoholic hepatitis will not benefit from treatment. We suggest that future clinical trials need to focus on end points other than mortality. This Review discusses the main pathways associated with the progression of liver disease, as well as potential therapeutic strategies targeting these pathways.
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Navid A, Ng DM, Stewart BJ, Wong SE, Lightstone FC. Quantitative In Silico analysis of transient metabolism of acetaminophen and associated causes of hepatotoxicity in humans. In Silico Pharmacol 2013. [PMCID: PMC4750864 DOI: 10.1186/2193-9616-1-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Lee SJ, Kim SY, Min H. Effects of vitamin C and E supplementation on oxidative stress and liver toxicity in rats fed a low-fat ethanol diet. Nutr Res Pract 2013; 7:109-14. [PMID: 23610603 PMCID: PMC3627927 DOI: 10.4162/nrp.2013.7.2.109] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/12/2013] [Accepted: 02/20/2013] [Indexed: 01/29/2023] Open
Abstract
We compared the preventive capacity of high intakes of vitamin C (VC) and vitamin E (VE) on oxidative stress and liver toxicity in rats fed a low-fat ethanol diet. Thirty-two Wistar rats received the low fat (10% of total calories) Lieber-DeCarli liquid diet as follows: either ethanol alone (Alc group, 36% of total calories) or ethanol in combination with VC (Alc + VC group, 40 mg VC/100 g body weight) or VE (Alc + VE group, 0.8 mg VE/100 g body weight). Control rats were pair-fed a liquid diet with the Alc group. Ethanol administration induced a modest increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), conjugated dienes (CD), and triglycerides but decreased total radical-trapping antioxidant potential (TRAP) in plasma. VE supplementation to alcohol-fed rats restored the plasma levels of AST, CD, and TRAP to control levels. However, VC supplementation did not significantly influence plasma ALT, AST, or CD. In addition, a significant increase in plasma aminothiols such as homocysteine and cysteine was observed in the Alc group, but cysteinylglycine and glutathione (GSH) did not change by ethanol feeding. Supplementing alcohol-fed rats with VC increased plasma GSH and hepatic S-adenosylmethionine, but plasma levels of aminothiols, except GSH, were not influenced by either VC or VE supplementation in ethanol-fed rats. These results indicate that a low-fat ethanol diet induces oxidative stress and consequent liver toxicity similar to a high-fat ethanol diet and that VE supplementation has a protective effect on ethanol-induced oxidative stress and liver toxicity.
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Affiliation(s)
- Soo-Jung Lee
- Department of Food and Nutrition, College of Bio-Nano Science, Hannam University, 461-6 Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Korea
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Affiliation(s)
- Neil Kaplowitz
- Division of Gastroenterology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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ERUKAINURE O, AJIBOYE J, OKAFO O, KOSOK R, OWOLAB O, ADENEKAN I. ANTIOXIDANT EFFECT OF PINEAPPLE (ANANAS COSMOSUS) PEEL EXTRACT ON ALCOHOL-INDUCED OXIDATIVE STRESS IN SPLENIC TISSUES OF MALE ALBINO RATS. J Food Biochem 2011. [DOI: 10.1111/j.1745-4514.2011.00578.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Moreno C, Langlet P, Hittelet A, Lasser L, Degré D, Evrard S, Colle I, Lemmers A, Devière J, Le Moine O. Enteral nutrition with or without N-acetylcysteine in the treatment of severe acute alcoholic hepatitis: a randomized multicenter controlled trial. J Hepatol 2010; 53:1117-22. [PMID: 20801542 DOI: 10.1016/j.jhep.2010.05.030] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 05/13/2010] [Accepted: 05/28/2010] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Severe acute alcoholic hepatitis is associated with a high mortality rate. Oxidative stress is involved in the pathogenesis of acute alcoholic hepatitis. Previous findings had also suggested that enteral nutritional support might increase survival in patients with severe acute alcoholic hepatitis. Therefore, the aim of the present study was to evaluate the efficacy of N-acetylcysteine in combination with adequate nutritional support in patients with severe acute alcoholic hepatitis. METHODS Patients with biopsy-proven acute alcoholic hepatitis and mDF ≥32 were randomized to receive N-acetylcysteine intravenously or a placebo perfusion along with adequate nutritional support for 14 days. The primary endpoint was 6-month survival; secondary endpoints were biological parameter evolution and infection rate. RESULTS Fifty-two patients were randomized in the study (28 into the N-acetylcysteine arm, 24 into the control arm), and among them, five were excluded from the analysis for protocol violation. The two groups did not differ in baseline characteristics. Survival rates at 1 and 6 months in N-acetylcysteine and control groups were 70.2 vs. 83.8% (p=0.26) and 62.4 vs. 67.1% (p=0.60), respectively. Early biological changes, documented infection rate at 1 month, and incidence of hepatorenal syndrome did not differ between the two groups. CONCLUSIONS In this study, high doses of intravenous N-acetylcysteine therapy for 14 days conferred neither survival benefits nor early biological improvement in severe acute alcoholic hepatitis patients with adequate nutritional support. However, these results must be viewed with caution, since the study suffered from a lack of power.
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Affiliation(s)
- Christophe Moreno
- Department of Gastroenterology, Hepatopancreatology and Digestive Oncology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium.
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Cederbaum AI, Lu Y, Wu D. Role of oxidative stress in alcohol-induced liver injury. Arch Toxicol 2009; 83:519-48. [PMID: 19448996 DOI: 10.1007/s00204-009-0432-0] [Citation(s) in RCA: 428] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 04/28/2009] [Indexed: 02/06/2023]
Abstract
Reactive oxygen species (ROS) are highly reactive molecules that are naturally generated in small amounts during the body's metabolic reactions and can react with and damage complex cellular molecules such as lipids, proteins, or DNA. Acute and chronic ethanol treatments increase the production of ROS, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Special emphasis is placed on CYP2E1, which is induced by alcohol and is reactive in metabolizing and activating many hepatotoxins, including ethanol, to reactive products, and in generating ROS.
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Affiliation(s)
- Arthur I Cederbaum
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, Box 1603, One Gustave L Levy Place, New York, NY 10029, USA.
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Affiliation(s)
- Irma Laonigro
- Department of Medical and Occupational Sciences; Institute of Internal Medicine, University of Foggia; Foggia Italy
| | - Michele Correale
- Department of Cardiology; ‘Ospedali Riuniti’ OO.RR, University of Foggia; viale L Pinto, 1 71100 Foggia Italy
| | - Matteo Di Biase
- Department of Cardiology; ‘Ospedali Riuniti’ OO.RR, University of Foggia; viale L Pinto, 1 71100 Foggia Italy
| | - Emanuele Altomare
- Department of Medical and Occupational Sciences; Institute of Internal Medicine, University of Foggia; Foggia Italy
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Fernández A, Colell A, Caballero F, Matías N, García-Ruiz C, Fernández-Checa JC. Mitochondrial S-adenosyl-L-methionine transport is insensitive to alcohol-mediated changes in membrane dynamics. Alcohol Clin Exp Res 2009; 33:1169-80. [PMID: 19389197 DOI: 10.1111/j.1530-0277.2009.00940.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Alcohol-induced liver injury is associated with decreased S-adenosyl-l-methionine (SAM)/S-adenosyl-l-homocysteine (SAH) ratio and mitochondrial glutathione (mGSH) depletion, which has been shown to sensitize hepatocytes to tumor necrosis factor (TNF). AIMS As the effect of alcohol on mitochondrial SAM (mSAM) has been poorly characterized, our aim was to examine the status and transport of mSAM in relation to that of mGSH during alcohol intake. METHODS Sprague-Dawley rats were pair fed Lieber-DeCarli diets containing alcohol for 1 to 4 weeks and liver fractionated into cytosol and mitochondria to examine the mSAM transport and its sensitivity to membrane dynamics. RESULTS We found that cytosol SAM was depleted from the first week of alcohol feeding, with mSAM levels paralleling these changes. Cytosol SAH, however, increased during the first 3 weeks of alcohol intake, whereas its mitochondrial levels remained unchanged. mGSH depletion occurred by 3 to 4 weeks of alcohol intake due to cholesterol-mediated impaired transport from the cytosol. In contrast to this outcome, the transport of SAM into hepatic mitochondria was unaffected by alcohol intake and resistant to cholesterol-mediated perturbations in membrane dynamics; furthermore cytosolic SAH accumulation in primary hepatocytes by SAH hydrolase inhibition reproduced the mSAM depletion by alcohol due to the competition of SAH with SAM for mitochondrial transport. However, alcohol feeding did not potentiate the sensitivity to inhibition by SAH accumulation. CONCLUSIONS Alcohol-induced mSAM depletion precedes that of mGSH and occurs independently of alcohol-mediated perturbations in membrane dynamics, disproving an inherent defect in the mSAM transport by alcohol. These findings suggest that the early mSAM depletion may contribute to the alterations of mitochondrial membrane dynamics and the subsequent mGSH down-regulation induced by alcohol feeding.
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Affiliation(s)
- Anna Fernández
- Liver Unit and Centro de Investigaciones Biomédicas Esther Koplowitz, Instituto Investigaciones Biomédicas de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Spain
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Yuan L, Kaplowitz N. Glutathione in liver diseases and hepatotoxicity. Mol Aspects Med 2008; 30:29-41. [PMID: 18786561 DOI: 10.1016/j.mam.2008.08.003] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 08/18/2008] [Accepted: 08/18/2008] [Indexed: 02/08/2023]
Abstract
Glutathione (GSH) is a major antioxidant as well as redox and cell signaling regulator. GSH guards cells against oxidative injury by reducing H(2)O(2) and scavenging reactive oxygen and nitrogen radicals. In addition, GSH-induced redox shift with or without ROS subjects some cellular proteins to varied forms of oxidation, altering the function of signal transduction and transcription factor molecules. Increasing evidence supports the important role of ROS and GSH in modulating multiple signaling pathways. TNF-alpha and Fas signaling, NF-kappaB, JNK and mitochondrial apoptotic pathways are the focus of this review. The redox regulation either can switch on/off or regulate the threshold for some crucial events in these pathways. Notably, mitochondrial GSH depletion induces increased mitochondrial ROS exposure which impairs bioenergetics and promotes mitochondrial permeability transition pore opening which is critical for cell death. Depending on the extent of mitochondrial damage, NF-kappaB inhibition and JNK activation, hepatocytes may either undergo different modes of cell death (apoptosis or necrosis) or be sensitized to cell-death stimuli (i.e. TNF-alpha). These processes have been implicated in the pathogenesis of many liver diseases.
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Affiliation(s)
- Liyun Yuan
- Internal Medicine, University of Southern California, USA
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Song Z, Zhou Z, Song M, Uriarte S, Chen T, Deaciuc I, McClain CJ. Alcohol-induced S-adenosylhomocysteine accumulation in the liver sensitizes to TNF hepatotoxicity: possible involvement of mitochondrial S-adenosylmethionine transport. Biochem Pharmacol 2007; 74:521-31. [PMID: 17574213 PMCID: PMC1995460 DOI: 10.1016/j.bcp.2007.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 05/04/2007] [Accepted: 05/07/2007] [Indexed: 02/06/2023]
Abstract
Hepatocytes are resistant to tumor necrosis factor-alpha- (TNF) induced killing/apoptosis under normal circumstances, but primary hepatocytes from rats chronically fed alcohol have increased TNF cytotoxicity. Therefore, there must be mechanism(s) by which alcohol exposure "sensitizes" to TNF hepatotoxicity. Abnormal metabolism of methionine and S-adenosylmethionine (SAM) are well-documented acquired metabolic abnormalities in ALD. S-adenosylhomocysteine (SAH) is the product of SAM in hepatic transmethylation reactions, and SAH hydrolase (SAHH) is the only enzyme to metabolize SAH to homocysteine and adenosine. Our previous studies demonstrated that chronic intracellular accumulation of SAH sensitized hepatocytes to TNF cytotoxicity in vitro. In the current study, we extended our previous observations by further characterizing the effects of chronic alcohol intake on mitochondrial SAM levels in liver and examining its possible involvement in SAH sensitization to TNF hepatotoxicity. Chronic alcohol consumption in mice not only increased cytosolic SAH levels, but also decreased mitochondrial SAM concentration, leading to decreased mitochondrial SAM to SAH ratio. Moreover, accumulation of hepatic SAH induced by administration of 3-deaza-adenosine (DZA-a potent inhibitor of SAHH) enhanced lipopolysaccharide (LPS)/TNF hepatotoxicity in mice in vivo. Inhibition of SAHH by DZA resulted not only in accumulation of cytoplasmic SAH, but also in depletion of the mitochondrial SAM pool. Further studies using mitochondrial SAM transporter inhibitors showed that inhibition of SAM transport into mitochondria sensitized HepG2 cells to TNF cytotoxicity. In conclusion, our results demonstrate that depletion of the mitochondrial SAM pool by SAH, which is elevated during chronic alcohol consumption, plays a critical role in SAH induced sensitization to TNF hepatotoxicity.
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Affiliation(s)
- Zhenyuan Song
- Department of Medicine, University of Louisville Medical Center, Louisville, KY 40292, United States.
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21
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Jones DP. Disruption of mitochondrial redox circuitry in oxidative stress. Chem Biol Interact 2006; 163:38-53. [DOI: 10.1016/j.cbi.2006.07.008] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 07/18/2006] [Accepted: 07/19/2006] [Indexed: 02/07/2023]
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Free radical scavenging activity of the marine mangrove Rhizophora apiculata bark extract with reference to naphthalene induced mitochondrial dysfunction. Chem Biol Interact 2006; 163:170-5. [PMID: 16860784 DOI: 10.1016/j.cbi.2006.06.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 06/08/2006] [Accepted: 06/16/2006] [Indexed: 10/24/2022]
Abstract
Rhizophora apiculata bark extract was tested for its free radical scavenging activity and protective role against mitochondrial dysfunction in naphthalene stressed rats. Lipid peroxidation activity was increased and activity of mitochondrial enzymes (cytochrome-c-oxidase, NADH-dehydrogenase, alpha-ketoglutarate dehydrogenase and succinate dehydrogenase) and glutathione was decreased in the liver and kidney of rats intoxicated with naphthalene when compared to control rats. Intraperitoneal administration of plant extract significantly reduced the lipid peroxidation, increased the activity of mitochondrial enzymes and increased glutathione to near control levels. These results suggest that the sulfated polysaccharides in R. apiculata play a protective role through their free radical scavenging properties.
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Vijayavel K, Balasubramanian MP. Changes in oxygen consumption and respiratory enzymes as stress indicators in an estuarine edible crab Scylla serrata exposed to naphthalene. CHEMOSPHERE 2006; 63:1523-31. [PMID: 16289245 DOI: 10.1016/j.chemosphere.2005.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 08/27/2005] [Accepted: 09/26/2005] [Indexed: 05/05/2023]
Abstract
The sublethal effect of naphthalene was studied on the physiology of a mud crab Scylla serrata. The 96 h acute toxicity of naphthalene was determined and found to be 28 mg 1(-1) (LC100), 18 mg 1(-1) (LC50), 10 mg 1(-1) (LC0) respectively. The 30 days sublethal effect (LC0) 9 mg 1(-1), 8 mg 1(-1), 10 mg 1(-1), of naphthalene was investigated in the crab S. serrata with reference to oxygen consumption and changes in the activity of respiratory enzymes. The results indicated that naphthalene caused disturbance in the normal physiology of the crab. The bioaccumulation of naphthalene was also investigated in gills, hepatopancreas, haemolymph and ovary. The consumption of oxygen increased in the naphthalene medium when compared with that of the crabs exposed to naphthalene free medium. A decreased trend in the activity of respiratory enzymes such as lactate dehydrogenase (LDH), isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), alpha-ketoglutarate dehydrogenase (alpha-KDH) and glutathione (GSH) were recorded in the hepatopancreas, ovary and gills of S. serrata for all the tested concentrations of naphthalene and the results were analyzed for their significance.
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Affiliation(s)
- K Vijayavel
- Department of Pharmacology and Environmental Toxicology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai 600 113, Tamil Nadu, India.
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Louvet A, Boitard J, Dharancy S, Duriez A, Deltenre P, Paris JC, Mathurin P. La mésaventure thérapeutique du paracétamol chez le buveur excessif. ACTA ACUST UNITED AC 2006; 30:769-74. [PMID: 16801901 DOI: 10.1016/s0399-8320(06)73312-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rydström J. Mitochondrial NADPH, transhydrogenase and disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:721-6. [PMID: 16730324 DOI: 10.1016/j.bbabio.2006.03.010] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/21/2006] [Accepted: 03/14/2006] [Indexed: 11/23/2022]
Abstract
Ever since its discovery in 1953 by N. O. Kaplan and coworkers, the physiological role of the proton-translocating transhydrogenase has generally been assumed to be that of generating mitochondrial NADPH. Mitochondrial NADPH can be used in a number of important reactions/processes, e.g., biosynthesis, maintenance of GSH, apoptosis, aging etc. This assumed role has found some support in bacteria but not in higher eukaryotes, a situation which changed dramatically with two recent but separate findings, both using transhydrogenase knockouts, in the nematode C. elegans and the mouse strain C57BL/6J. The latter, which is due to a spontaneous deletion mutation in the Nnt gene, was serendipitously found during investigations of the diabetic properties of these mice. The implications of these findings for the overall role of transhydrogenase in cell metabolism and disease are discussed.
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Affiliation(s)
- Jan Rydström
- Department of Biochemistry and Biophysics, Göteborg University, 405 30 Göteborg, Sweden.
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Abstract
Acute and chronic ethanol treatment has been shown to increase the production of reactive oxygen species, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Many of the seminal reports in this topic have been published in Hepatology , and it is fitting to review this research area for the 25th Anniversary Issue of the Journal.
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Affiliation(s)
- Aparajita Dey
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY, USA
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Hansen JM, Go YM, Jones DP. Nuclear and mitochondrial compartmentation of oxidative stress and redox signaling. Annu Rev Pharmacol Toxicol 2006; 46:215-34. [PMID: 16402904 DOI: 10.1146/annurev.pharmtox.46.120604.141122] [Citation(s) in RCA: 299] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
New methods to measure thiol oxidation show that redox compartmentation functions as a mechanism for specificity in redox signaling and oxidative stress. Redox Western analysis and redox-sensitive green fluorescent proteins provide means to quantify thiol/disulfide redox changes in specific subcellular compartments. Analyses using these techniques show that the relative redox states from most reducing to most oxidizing are mitochondria > nuclei > cytoplasm > endoplasmic reticulum > extracellular space. Mitochondrial thiols are an important target of oxidant-induced apoptosis and necrosis and are especially vulnerable to oxidation because of the relatively alkaline pH. Maintenance of a relatively reduced nuclear redox state is critical for transcription factor binding in transcriptional activation in response to oxidative stress. The new methods are applicable to a broad range of experimental systems and their use will provide improved understanding of the pharmacologic and toxicologic actions of drugs and toxicants.
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Affiliation(s)
- Jason M Hansen
- Department of Medicine and Clinical Biomarkers Laboratory, Division of Pulmonary Medicine, Emory University, Atlanta, GA 30322, USA.
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Affiliation(s)
- Philippe Mathurin
- Service d'Hépato-Gastroentérologie Hôpital Claude Huriez 2(ème) étage Est, Avenue Michel Polonovski, CHRU Lille 59037, France.
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Abstract
Age-dependent change in the effects of acute ethanol administration on female rat liver was investigated. Female Sprague-Dawley rats, each aged 4, 12, or 50 weeks, received ethanol (2 g/kg) via a catheter inserted into a jugular vein. Ethanol elimination rate (EER), most rapid in the 4 weeks old rats, was decreased as the age advanced. Hepatic alcohol dehydrogenase activity was not altered by age, but microsomal p-nitrophenol hydroxylase activity was significantly greater in the 4 weeks old rats. Relative liver weight decreased with age increase in proportion to reduction of EER. Hepatic triglyceride and malondialdehyde concentrations increased spontaneously in the 50 weeks old nai;ve rats. Ethanol administration (3 g/kg, ip) elevated malondialdehyde and triglyceride contents only in the 4 and the 12 weeks old rats. Hepatic glutathione concentration was increasingly reduced by ethanol with age increase. Ethanol decreased cysteine concentration in the 4 weeks old rats, but elevated it significantly in the older rats. Inhibition of gamma-glutamylcysteine synthetase activity by ethanol was greater with age increase, which appeared to be responsible for the increase in hepatic cysteine. The results indicate that age does not affect the ethanol metabolizing capacity of female rat liver, but the overall ethanol metabolism is decreased in accordance with the reduction of relative liver size. Accordingly induction of acute alcoholic fatty liver is less significant in the old rats. However, progressively greater depletion of glutathione by ethanol in older rats suggests that susceptibility of liver to oxidative damage would be increased as animals grow old.
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Affiliation(s)
- Young C Kim
- College of Pharmacy, Seoul National University, San 56-1 Shinrim-Dong, Kwanak-Ku, Seoul, South Korea.
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30
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Coll O, Colell A, García-Ruiz C, Kaplowitz N, Fernández-Checa JC. Sensitivity of the 2-oxoglutarate carrier to alcohol intake contributes to mitochondrial glutathione depletion. Hepatology 2003; 38:692-702. [PMID: 12939596 DOI: 10.1053/jhep.2003.50351] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mitochondrial pool of reduced glutathione (mGSH) is known to play a protective role against liver injury and cytokine-mediated cell death. However, the identification of the mitochondrial carriers involved in its transport in hepatocellular mitochondria remains unestablished. In this study, we show that the functional expression of the 2-oxoglutarate carrier from HepG2 cells in mitochondria from Xenopus laevis oocytes conferred a reduced glutathione (GSH) transport activity that was inhibited by phenylsuccinate, a specific inhibitor of the carrier. In addition, the mitochondrial transport of GSH and 2-oxoglutarate in isolated mitochondria from rat liver exhibited mutual competition and sensitivity to glutamate and phenylsuccinate. Interestingly, the kinetics of 2-oxoglutarate transport in rat liver mitochondria displayed a single Michaelis-Menten component with a Michaelis constant of 3.1 +/- 0.3 mmol/L and maximum velocity of 1.9 +/- 0.1 nmol/mg protein/25 seconds. Furthermore, the initial rate of 2-oxoglutarate was reduced in mitochondria from alcohol-fed rat livers, an effect that was not accompanied by an alcohol-induced decrease in the 2-oxoglutarate messenger RNA levels but rather by changes in mitochondrial membrane dynamics induced by alcohol. The fluidization of mitochondria by the fluidizing agent 2-(2-methoxyethoxy)ethyl 8-(cis-2-n-octylcyclopropyl) (A(2)C) restored the initial transport rate of both GSH and 2-oxoglutarate. Finally, these changes were reproduced in normal liver mitochondria enriched in cholesterol where the fluidization of cholesterol-enriched mitochondria with A(2)C restored the order membrane parameter and the mitochondrial 2-oxoglutarate uptake. In conclusion, these findings provide unequivocal evidence for 2-oxoglutarate as a GSH carrier and its sensitivity to membrane dynamics perturbation contributes in part to the alcohol-induced mGSH depletion.
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Affiliation(s)
- Olga Coll
- Liver Unit, Hospital Clínic i Provincial, Institut de Malalties Digestives, Instituto de Investigaciones Biomédicas August Pi i Sunyer, Consejo Superior de Investigaciones Científicas, Barcelona, Spain
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Saravanan R, Prakasam A, Ramesh B, Pugalendi KV. Influence of Piper betle on hepatic marker enzymes and tissue antioxidant status in ethanol-treated Wistar rats. J Med Food 2003; 5:197-204. [PMID: 12639394 DOI: 10.1089/109662002763003348] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Piper betle L. is a commonly used masticatory in Asia. This study was carried out to investigate the hepatoprotective and antioxidant properties of P. betle, using ethanol intoxication as a model of hepatotoxic and oxidative damage. Ethanol-treated rats exhibited elevation of hepatic marker enzymes and disturbances in antioxidant defense when compared with normal rats. Oral administration of P. betle extract (100, 200, or 300 mg/kg body weight) for 30 days significantly (P <.05) decreased aspartate aminotransferase (AST), alanine aminotransferase (ALT), thiobarbituric acid reactive substances (TBARS), and lipid hydroperoxides in ethanol treated rats. The extract also improved the tissue antioxidant status by increasing the levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) and the activities of free radical-detoxifying enzymes such as superoxide dismutase, catalase, and glutathione peroxidase in liver and kidney of ethanol-treated rats. The highest dose of P. betle extract (300 mg/kg body weight) was most effective. The results were comparable with the known hepatoprotective drug, silymarin. These results indicate that P. betle could afford a significant hepatoprotective and antioxidant effect.
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Affiliation(s)
- R Saravanan
- Department of Biochemistry, Faculty of Science, Annamalai University, Annamalainagar - 608002, Tamil Nadu, India
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Fernández-Checa JC, Colell A, García-Ruiz C. S-Adenosyl-L-methionine and mitochondrial reduced glutathione depletion in alcoholic liver disease. Alcohol 2002; 27:179-83. [PMID: 12163147 DOI: 10.1016/s0741-8329(02)00229-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The pathogenesis of alcohol-induced liver disease is not well understood, and many factors have been described to contribute to the progressive loss of liver functions, including the overgeneration of reactive oxygen species. Mitochondria are specific targets of the toxic effects of ethanol, reflected in the loss of phosphorylative oxidation and defective ATP generation, which underlie one of the hallmarks of the hepatic alterations induced by chronic alcohol intake. Mitochondrial reduced glutathione (GSH), whose primary function is to maintain a competitive functional organelle, becomes depleted by alcohol intake. Furthermore, GSH depletion in hepatocyte mitochondria has been revealed as an important mechanism in the sensitization of liver to alcohol-induced injury. This depletion of the mitochondrial GSH level is determined by an impaired transport of GSH from the cytosol into the mitochondrial matrix owing to a partial inactivation of mitochondrial GSH carrier. The loss of function of this specific mitochondrial transporter is due to the alterations in the physicochemical properties of the inner mitochondrial membrane caused by alcohol. Because of the primary defect in the transport of cytosolic GSH into mitochondria, GSH precursors are inefficient in replenishing the levels of mitochondrial GSH despite significant increase in cytosolic GSH. Supplementation of S-adenosyl-L-methionine (SAM) to rats fed alcohol chronically has been shown to replete the mitochondrial GSH levels because of normalization of the microviscosity of the mitochondrial inner membrane. Because of the instrumental role of GSH in mitochondria in hepatocyte survival against inflammatory cytokines, its repletion by SAM feeding may underlie the potential therapeutic use of this hepatoprotective agent in the treatment of alcohol-induced liver injury.
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Abstract
Several studies have shown that pyruvate can scavenge H(2)O(2) and protect from H(2)O(2)-mediated cell injury. Mitochondria are critical participants in the control of apoptotic and necrotic cell death. Mitochondrial GSH plays an important role in the maintenance of cell functions and viability by metabolism of oxygen free radicals generated by the respiratory chain. Since loss of GSH, especially mitochondrial GSH, is associated with increased production of reactive oxygen species and cell toxicity, the ability of pyruvate to protect against these actions was evaluated. Adding pyruvate to HepG2 cells depleted of GSH by treatment with l-buthionine sulfoximine (BSO) surprisingly caused loss of viability after 24 and 48 h of incubation. Anoxia, treatment with antioxidants, and infection with cytosolic catalase, and interestingly, catalase expressed in the mitochondrial compartment were able to rescue the HepG2 cells from this pyruvate plus BSO injury, suggesting a key role for H(2)O(2), and lipid peroxides as mediators in the cytotoxicity. This toxicity and cell death observed was linked to damage to the mitochondria as evidenced by the increased lipid peroxidation in total homogenate and mitochondrial fraction, loss of mitochondrial membrane potential, and a decrease in protein-sulfhydryl groups. The type of cell death observed under these conditions was a mixture of apoptosis and necrosis. These results suggest that the protective ability of pyruvate against oxidant damage requires a functional GSH pool, especially in the mitochondrial compartment, and that in the absence of GSH, pyruvate increases cell injury by damaging the mitochondria, presumably as a consequence of enhanced electron flow and reactive oxygen production by the respiratory chain.
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Affiliation(s)
- Montserrat Marí
- Department of Biochemistry and Molecular Biology, Mount Sinai School of Medicine, One Gustave Levy Place, New York, NY 10029, USA
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34
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Abstract
Serum gamma-glutamyl transferase (GGT) has been widely used as an index of liver dysfunction and marker of alcohol intake. The last few years have seen improvements in these areas and advances in understanding of its physiological role in counteracting oxidative stress by breaking down extracellular glutathione and making its component amino acids available to the cells. Conditions that increase serum GGT, such as obstructive liver disease, high alcohol consumption, and use of enzyme-inducing drugs, lead to increased free radical production and the threat of glutathione depletion. However, the products of the GGT reaction may themselves lead to increased free radical production, particularly in the presence of iron. There have also been important advances in the definition of the associations between serum GGT and risk of coronary heart disease, Type 2 diabetes, and stroke. People with high serum GGT have higher mortality, partly because of the association between GGT and other risk factors and partly because GGT is an independent predictor of risk. This review aims to summarize the knowledge about GGT's clinical applications, to present information on its physiological roles, consider the results of epidemiological studies, and assess how far these separate areas can be combined into an integrated view.
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Affiliation(s)
- J B Whitfield
- Department of Clinical Biochemistry, Royal Prince Alfred Hospital, and University of Sydney, NSW, Australia.
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35
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Brown LAS, Harris FL, Bechara R, Guidot DM. Effect of Chronic Ethanol Ingestion on Alveolar Type II Cell: Glutathione and Inflammatory Mediator-Induced Apoptosis. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02320.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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36
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Abstract
Alcoholic liver disease (ALD) develops as a consequence of priming and sensitizing mechanisms rendered by cross-interactions of primary mechanistic factors and secondary risk factors. This concept, albeit not novel, is becoming widely accepted by the field, and more research is directed toward identifying and characterizing the interfaces of the cross-interactions to help understand individual predisposition to the disease. Another pivotal development is the beginning of cell type-specific research to elucidate specific contributions not only of hepatocytes, but also of hepatic macrophages, liver-associated lymphocytes, sinusoidal endothelial cells, and hepatic stellate cells to sensitizing and priming mechanisms. In particular, the critical role of hepatic macrophages has been highlighted and the priming mechanisms concerning this paracrine effect have been proposed. Glutathione depletion in hepatocyte mitochondria is considered the most important sensitizing mechanism. One of the contributing factors is decreased methionine metabolism. Remaining key questions include how altered methionine metabolism contribute to the pathogenesis of ALD; how cross-talk among nonparenchymal liver cells or between nonparenchymal cells and hepatocytes leads to ALD; how dysfunctional mitochondria determine the type of cell death in ALD; and what secondary factors are critical for the development of advanced ALD such as alcoholic hepatitis and cirrhosis.
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Affiliation(s)
- H Tsukamoto
- USC-UCLA Research Center for Alcoholic Liver and Pancreatic Diseases, USC Research Center for Liver Diseases, Department of Pathology, Keck School of Medicine of USC, Los Angeles, California 90033, USA.
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Chronic Alcohol Consumption and Cerebral Indices of Oxidative Stress: Is There a Link? Alcohol Clin Exp Res 2001. [DOI: 10.1097/00000374-200105000-00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Gotz ME, Janetzky B, Pohli S, Gottschalk A, Gsell W, Tatschner T, Ransmayr G, Leblhuber F, Gerlach M, Reichmann H, Riederer P, Boning J. Chronic Alcohol Consumption and Cerebral Indices of Oxidative Stress: Is There a Link? Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02272.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Sinclair JF, Szakacs JG, Wood SG, Kostrubsky VE, Jeffery EH, Wrighton SA, Bement WJ, Wright D, Sinclair PR. Acetaminophen hepatotoxicity precipitated by short-term treatment of rats with ethanol and isopentanol: protection by triacetyloleandomycin. Biochem Pharmacol 2000; 59:445-54. [PMID: 10644054 DOI: 10.1016/s0006-2952(99)00349-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Ethanol and isopentanol are the predominant alcohols in alcoholic beverages. We have reported previously that pretreatment of rats with a liquid diet containing 6.3% ethanol plus 0.5% isopentanol for 7 days results in a synergistic increase in acetaminophen hepatotoxicity, compared with rats treated with either alcohol alone. Here, we investigated the role of CYP3A in acetaminophen hepatotoxicity associated with the combined alcohol treatment. Triacetyloleandomycin, a specific inhibitor of CYP3A, protected rats pretreated with ethanol along with isopentanol from acetaminophen hepatotoxicity. At both 0.25 and 0.5 g acetaminophen/kg, triacetyloleandomycin partially prevented elevations in serum levels of alanine aminotransferase. At 0.25 g acetaminophen/kg, triacetyloleandomycin completely protected 6 of 8 rats from histologically observed liver damage, and partially protected the remaining 2 rats. At 0.5 g acetaminophen/kg, triacetyloleandomycin decreased histologically observed liver damage in 7 of 15 rats. In rats pretreated with ethanol plus isopentanol, CYP3A, measured immunohistochemically, was decreased by acetaminophen treatment. This effect was prevented by triacetyloleandomycin. These results suggest that CYP3A has a major role in acetaminophen hepatotoxicity in animals administered the combined alcohol treatment. We also found that exposure to ethanol along with 0.1% isopentanol for only 3 days resulted in maximal increases in acetaminophen hepatotoxicity by the combined alcohol treatment, suggesting that short-term consumption of alcoholic beverages rich in isopentanol may be a risk for developing liver damage from acetaminophen.
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Affiliation(s)
- J F Sinclair
- Veterans Administration Medical Center, White River Junction, VT 05009, USA.
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40
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Corrales FJ, Ruiz F, Mato JM. In vivo regulation by glutathione of methionine adenosyltransferase S-nitrosylation in rat liver. J Hepatol 1999; 31:887-94. [PMID: 10580587 DOI: 10.1016/s0168-8278(99)80291-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Ethanol consumption and pathological conditions such as cirrhosis lead to a reduction of hepatic glutathione. Hepatic methionine adenosyltransferase, the enzyme that synthesizes S-adenosylmethionine, the major methylating agent, is regulated in vivo by glutathione levels. We have previously shown that nitric oxide inactivates methionine adenosyltransferase in vivo by S-nitrosylation. In this study, we aimed to investigate the regulation by glutathione of methionine adenosyltransferase S-nitrosylation in rat liver. METHODS Rat hepatocytes and whole animals were treated with buthionine sulfoximine, an inhibitor of glutathione synthesis, and methionine adenosyltransferase S-nitrosylation and activity were determined. RESULTS In hepatocytes, buthionine sulfoximine led to the S-nitrosylation and inactivation of methionine adenosyltransferase. Restoring glutathione levels in hepatocytes treated with buthionine sulfoximine, by the addition of glutathione monoethyl ester, a permeable derivative of glutathione, led to the denitrosylation and reactivation of methionine adenosyltransferase. In whole animals, buthionine sulfoximine led also to methionine adenosyltransferase S-nitrosylation and inactivation. S-Nitrosylation and inactivation of methionine adenosyltransferase induced by buthionine sulfoximine in whole animals was prevented by glutathione monoethyl ester. CONCLUSIONS These results indicate that in vivo hepatic methionine adenosyltransferase exists in two forms in equilibrium, nitrosylated (inactive) and denitrosylated (active), which are regulated by both the cellular levels of nitric oxide and glutathione.
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Affiliation(s)
- F J Corrales
- Department of Internal Medicine, School of Medicine, Universidad de Navarra, Pamplona, Spain
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42
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Galli A, Price D, Crabb D. High-level expression of rat class I alcohol dehydrogenase is sufficient for ethanol-induced fat accumulation in transduced HeLa cells. Hepatology 1999; 29:1164-70. [PMID: 10094961 DOI: 10.1002/hep.510290420] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The mechanisms by which ethanol causes fatty liver are complex. Reducing equivalents generated during ethanol oxidation inhibit tricarboxylic acid cycle activity and fatty acid oxidation. In addition, ethanol inhibits lipoprotein export and increases fatty acid uptake and lipid peroxidation. To test the role that alcohol metabolism by alcohol dehydrogenase (ADH) has on cellular lipid metabolism, a cell line expressing rat ADH was generated by transducing HeLa cells with an ADH-expressing retrovirus. The cells expressed high levels of ADH protein and had ADH activity similar to that of liver. Exposure of the cells to 20 mmol/L ethanol for 24 hours led to substantial accumulation of free fatty acids and triacylglycerol in the transduced, but not wild-type, HeLa cells. The rate of synthesis of saponifiable lipid was increased significantly by ethanol under these conditions. Ethanol exposure also promoted triacylglycerol accumulation when the cells were incubated with linoleic acid. This was associated with a decrease in the rate at which the cells oxidized 1-[14-C]-linoleic acid. Fat accumulation was not prevented by including alpha-tocopherol in the medium, arguing against a role for lipid peroxidation. However, the presence of methylene blue completely prevented the fat accumulation. This was associated with a return of the elevated lactate/pyruvate ratio toward normal. These data suggest that generation of reducing equivalents by ADH was sufficient to cause fat accumulation in this cell model.
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Affiliation(s)
- A Galli
- Department of Clinical Pathophysiology, University of Florence, Florence, Italy
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Deaciuc IV, Fortunato F, D'Souza NB, Hill DB, Schmidt J, Lee EY, McClain CJ. Modulation of Caspase-3 Activity and Fas Ligand mRNA Expression in Rat Liver Cells In Vivo by Alcohol and Lipopolysaccharide. Alcohol Clin Exp Res 1999. [DOI: 10.1111/j.1530-0277.1999.tb04121.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Colell A, García-Ruiz C, Miranda M, Ardite E, Marí M, Morales A, Corrales F, Kaplowitz N, Fernández-Checa JC. Selective glutathione depletion of mitochondria by ethanol sensitizes hepatocytes to tumor necrosis factor. Gastroenterology 1998; 115:1541-51. [PMID: 9834283 DOI: 10.1016/s0016-5085(98)70034-4] [Citation(s) in RCA: 291] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Tumor necrosis factor (TNF)-alpha induces cell injury by generating oxidative stress from mitochondria. The purpose of this study was to determine the effect of ethanol on the sensitization of hepatocytes to TNF-alpha. METHODS Cultured hepatocytes from ethanol-fed (ethanol hepatocytes) or pair-fed (control hepatocytes) rats were exposed to TNF-alpha, and the extent of oxidative stress, gene expression, and viability were evaluated. RESULTS Ethanol hepatocytes, which develop a selective deficiency of mitochondrial glutathione (mGSH), showed marked susceptibility to TNF-alpha. The susceptibility to TNF-alpha, manifested as necrosis rather than apoptosis, was accompanied by a progressive increase in hydrogen peroxide that correlated inversely with cell survival. Nuclear factor kappaB activation by TNF-alpha was significantly greater in ethanol hepatocytes than in control hepatocytes, an effect paralleled by the expression of cytokine-induced neutrophil chemoattractant. Similar sensitization of normal hepatocytes to TNF-alpha was obtained by depleting the mitochondrial pool of GSH with 3-hydroxyl-4-pentenoate. Restoration of mGSH by S-adenosyl-L-methionine or by GSH-ethyl ester prevented the increased susceptibility of ethanol hepatocytes to TNF-alpha. CONCLUSIONS These results indicate that mGSH controls the fate of hepatocytes in response to TNF-alpha. Its depletion caused by alcohol consumption amplifies the power of TNF-alpha to generate reactive oxygen species, compromising mitochondrial and cellular functions that culminate in cell death.
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Affiliation(s)
- A Colell
- Liver Unit, Department of Medicine, Hospital Clinic i Provincial and Instituto Investigaciones Biomédicas, Consejo Superior Investigaciones Cientificas, Barcelona, Spain
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Morales A, Miranda M, Sánchez-Reyes A, Biete A, Fernández-Checa JC. Oxidative damage of mitochondrial and nuclear DNA induced by ionizing radiation in human hepatoblastoma cells. Int J Radiat Oncol Biol Phys 1998; 42:191-203. [PMID: 9747838 DOI: 10.1016/s0360-3016(98)00185-0] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE Since reactive oxygen species (ROS) act as mediators of radiation-induced cellular damage, the aim of our studies was to determine the effects of ionizing radiation on the regulation of hepatocellular reduced glutathione (GSH), survival and integrity of nuclear and mitochondrial DNA (mtDNA) in human hepatoblastoma cells (Hep G2) depleted of GSH prior to radiation. METHODS AND MATERIALS GSH, oxidized glutathione (GSSG), and generation of ROS were determined in irradiated (50-500 cGy) Hep G2 cells. Clonogenic survival, nuclear DNA fragmentation, and integrity of mtDNA were assessed in cells depleted of GSH prior to radiation. RESULTS Radiation of Hep G2 cells (50-400 cGy) resulted in a dose-dependent generation of ROS, an effect accompanied by a decrease of reduced GSH, ranging from a 15% decrease for 50 cGy to a 25% decrease for 400 cGy and decreased GSH/GSSG from a ratio of 17 to a ratio of 7 for controls and from 16 to 6 for diethyl maleate (DEM)-treated cells. Depletion of GSH prior to radiation accentuated the increase of ROS by 40-50%. The depletion of GSH by radiation was apparent in different subcellular sites, being particularly significant in mitochondria. Furthermore, depletion of nuclear GSH to 50-60% of initial values prior to irradiation (400 cGy) resulted in DNA fragmentation and apoptosis. Consequently, the survival of Hep G2 to radiation was reduced from 25% of cells not depleted of GSH to 10% of GSH-depleted cells. Fitting the survival rate of cells as a function of GSH using a theoretical model confirmed cellular GSH as a key factor in determining intrinsic sensitivity of Hep G2 cells to radiation. mtDNA displayed an increased susceptibility to the radiation-induced loss of integrity compared to nuclear DNA, an effect that was potentiated by GSH depletion in mitochondria (10-15% intact mtDNA in GSH-depleted cells vs. 25-30% of repleted cells). CONCLUSION GSH plays a critical protective role in maintaining nuclear and mtDNA functional integrity, determining the intrinsic radiosensitivity of Hep G2. Although the DNA repair is a complex process that is not yet completely understood, the protective role of GSH probably does not seem to involve the repair of classical DNA damage but may relate to modification of DNA damage dependent signaling.
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Affiliation(s)
- A Morales
- Instituto Investigaciones Biomédicas, August Pi i Suñer (IDIBAPS), CSIC-UB, Barcelona, Spain
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Coiro V, Vescovi PP. Controlled study of psychometric performance in abstinent alcoholics: masked comparison of the effects of 15-day intravenous treatments with S-adenosylmethionine or normal saline. Curr Ther Res Clin Exp 1997. [DOI: 10.1016/s0011-393x(97)80084-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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García-Ruiz C, Colell A, Marí M, Morales A, Fernández-Checa JC. Direct effect of ceramide on the mitochondrial electron transport chain leads to generation of reactive oxygen species. Role of mitochondrial glutathione. J Biol Chem 1997; 272:11369-77. [PMID: 9111045 DOI: 10.1074/jbc.272.17.11369] [Citation(s) in RCA: 601] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Ceramide is a sphingolipid that is generated in the signaling of inflammatory cytokines such as tumor necrosis factor (TNF), which exerts many functional roles depending on the cell type where it is produced. Since TNF cytotoxicity is mediated by overproduction of reactive oxygen species from mitochondria, we have examined the role of ceramide in generation of oxidative stress in isolated rat liver mitochondria. The present studies demonstrate that addition of N-acetylsphingosine (C2-ceramide) to mitochondria led to an increase of fluorescence of dihydrorhodamine 123 or dichlorofluorescein-stained mitochondria, indicating formation of hydrogen peroxide. Such effect was significant at 0.25 microM and maximal at 1-5 microM C2, decreasing at greater concentrations. This inductive effect of ceramide was mimicked by N-hexanoylsphingosine at the same concentration range, whereas the immediate precursor of C2, C2-dihydroceramide increased hydrogen peroxide at 1-5 microM. Sphingosine generated hydrogen peroxide at concentrations >/=10 microM, whereas diacylglycerol failed to increase hydrogen peroxide. The increase in hydrogen peroxide induced by C2 was not triggered by mitochondrial permeability transition as C2 did not induce mitochondrial swelling. Blocking electron transport chain at complex I and II prevented the increase in hydrogen peroxide induced by C2; however, interruption of electron flow at complex III by antimycin A potentiated the inductive effect of C2. Depletion of matrix GSH prior to exposure to ceramide resulted in a potentiated increase (2-fold) of hydrogen peroxide generation, leading to lipid peroxidation and loss of activity of respiratory chain complex IV compared with GSH-repleted mitochondria. Mitochondria isolated from TNF-treated cells showed an increase (2-3-fold) in the amount of ceramide compared with mitochondria from untreated cells. These results suggest that mitochondria are a target of ceramide produced in the signaling of TNF whose effect on mitochondrial electron transport chain leads to overproduction of hydrogen peroxide and consequently this phenomena may account for the generation of reactive oxygen species during TNF cytotoxicity.
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Affiliation(s)
- C García-Ruiz
- Instituto Investigaciones Biomédicas, Consejo Superior Investigaciones Científicas, Universidad de Barcelona, Barcelona 08036, Spain
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Hartley DP, Petersen DR. Co-Metabolism of Ethanol, Ethanol-Derived Acetaldehyde, and 4-Hydroxynonenal in Isolated Rat Hepatocytes. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb03764.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Chang ML, Klaidman LK, Adams JD. The effects of oxidative stress on in vivo brain GSH turnover in young and mature mice. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1997; 30:187-97. [PMID: 9165485 DOI: 10.1007/bf02815097] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Glutathione (GSH) synthetase activities and GSH turnover rates were examined during severe oxidative stress in the mouse brain as induced by t-butylhydroperoxide (t-BuOOH). Brain GSH synthetase activities in 8-mo-old mice in the cortex, striatum, thalamus, hippocampus, midbrain, and cerebellum were found to increase following t-BuOOH treatment. The effect of GSH synthesis on brain GSH turnover rates for 2- and 8-mo-old mice were determined after intracerebroventricular (icv) injection of [35S]cysteine. Rate constants for GSH turnover were determined by least-squares iterative minimization from the specific activity data from 20 min to 108 h after [35S]cysteine administration. GSH and glutathione disulfide (GSSG) specific activities were determined after separation by high-pressure liquid chromatography (HPLC). The half-life of GSH in the 2-mo-old mouse was 59.5 h and in the 8-mo-old mouse was 79.1 h. In summary, defense mechanisms against oxidative stress in the brain differ with age. Young mice can increase the cellular availability of GSH, whereas mature mice can increase GSH synthetase activity during oxidative stress. These differences make mature mice more susceptible to brain oxidative damage.
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Affiliation(s)
- M L Chang
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90033, USA
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Valerio LG, Parks T, Petersen DR. Alcohol mediates increases in hepatic and serum nonheme iron stores in a rat model for alcohol-induced liver injury. Alcohol Clin Exp Res 1996; 20:1352-61. [PMID: 8947310 DOI: 10.1111/j.1530-0277.1996.tb01134.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The notion that prolonged ethanol consumption promotes hepatocellular damage through interactions with iron was evaluated in rats fed ethanol with or without supplemental dietary carbonyl iron. The individual and combined pro-oxidant potential of these agents was evaluated in terms of their ability to perturb iron homeostasis and initiate hepatocellular injury. Sprague-Dawely rats received a high fat liquid diet for 8 weeks supplemented with: 35% ethanol-derived calories (Alcohol group), 0.02 to 0.04% (w/v) carbonyl iron (Iron group), ethanol plus carbonyl iron (Alcohol + Iron group), or a diet containing carbohydrate-derived isocaloric calories (Control group). Hepatic and serum nonheme iron stores were significantly elevated (p < 0.05) in all treatment groups, compared with the Controls. Catalytically active low-molecular weight iron was detected in rats consuming alcohol and was markedly elevated (p < 0.05) in rats ingesting iron alone or iron in combination with alcohol. Elevations in serum ALT indicated significant hepatocellular injury in rats ingesting only alcohol, but was most prominent in the rats consuming ethanol in combination with iron (p < 0.05). Significant hepatic fatty infiltration, increased hydroxyproline content, and perturbations in reduced glutathione were also observed in the Alcohol and Iron treatment groups. Histochemical assessment of hepatic iron sequestration revealed that alcohol feeding resulted in deposition of ferric iron in the centrilobular area of the liver lobule. This unique alcohol-mediated iron deposition was histologically graded above Control group and was observed in both hepatocytes and Kupffer cells. Data presented herein suggest that alcohol alone or in combination with iron results in rather specific lobular patterns of hepatic iron deposition relevant to iron overload observed in human alcoholics. Furthermore, data suggest that alcohol- and iron-initiated prefibrotic events occur before extensive hepatocellular necrosis.
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Affiliation(s)
- L G Valerio
- Department of Pharmaceutical Science, University of Colorado Health Sciences Center, Denver 80262, USA
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