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Seitz HK, Neuman MG. The History of Alcoholic Liver Disease: From an Unrecognized Disease to One of the Most Frequent Diseases in Hepatology. J Clin Med 2021; 10:858. [PMID: 33669694 PMCID: PMC7921942 DOI: 10.3390/jcm10040858] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 02/06/2023] Open
Abstract
This review describes the history of alcoholic liver disease from the beginning of the 1950s until now. It details how the hepatotoxicity of alcohol was discovered by epidemiology and basic research primarily by using new feeding techniques in rodents and primates. The article also recognizes the pioneering work of scientists who contributed to the understanding of the pathophysiology of alcoholic liver disease. In addition, clinical aspects, such as the development of diagnostics and treatment options for alcoholic liver disease, are discussed. Up-to-date knowledge of the mechanism of the disease in 2020 is presented.
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Affiliation(s)
- Helmut K. Seitz
- Centre of Liver and Alcohol Diseases, Ethianum Clinic, 69115 Heidelberg, Germany
- Faculty of Medicine, University of Heidelberg, 69117 Heidelberg, Germany
| | - Manuela G. Neuman
- In Vitro Drug Safety and Biotechnology and the Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5G 1L5, Canada;
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2
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Abstract
Over the last three decades, direct hepatotoxic effects of ethanol were established, some of which were linked to redox changes produced by NADH generated via the alcohol dehydrogenase (ADH) pathway and shown to affect the metabolism of lipids, carbohydrates, proteins, and purines. It was also determined that ethanol can be oxidized by a microsomal ethanol oxidizing system (MEOS) involving a specific cytochrome P-450; this newly discovered ethanol-inducible cytochrome P-450 (P-450 IIEi) contributes to ethanol metabolism, tolerance, energy wastage (with associated weight loss), and the selective hepatic perivenular toxicity of various xenobiotics. Their activation by P-450IIEi now provides an understanding of the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, over-the-counter analgesics, and chemical carcinogens. P-450 induction also explains depletion (and toxicity) of nutritional factors such as vitamin A. As a consequence, treatment with vitamin A and other nutritional factors is beneficial, but must take into account a narrowed therapeutic window in alcoholics who have increased needs for nutrients and also display an enhanced susceptibility to some of their adverse effects. Acetaldehyde (the metabolite produced from ethanol by either ADH or MEOS) impairs hepatic oxygen utilization and forms protein adducts, resulting in antibody production, enzyme inactivation, and decreased DNA repair. It also stimulates collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts, and causes glutathione depletion. Supplementation with S-adenosyl-L-methionine partly corrects the depletion and associated mitochondrial injury, whereas administration of polyunsaturated lecithin opposes the fibrosis. Thus, at the cellular level, the classic dichotomy between the nutritional and toxic effects of ethanol has now been bridged. The understanding of how the ensuing injury eventually results in irreversible scarring or cirrhosis may provide us with improved modalities for treatment and prevention.
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Affiliation(s)
- C S Lieber
- Alcohol Research & Treatment Center, Bronx VA Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
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Kaartinen K, Niemelä O, Syrjänen J, Alatalo P, Pörsti I, Harmoinen A, Pasternack A, Huhtala H, Mustonen J. IgA immune responses against acetaldehyde adducts and biomarkers of alcohol consumption in patients with IgA glomerulonephritis. Alcohol Clin Exp Res 2009; 33:1231-7. [PMID: 19389190 DOI: 10.1111/j.1530-0277.2009.00947.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The pathogenesis of IgA glomerulonephritis (IgAGN) involves intense deposition of IgAs within the glomerulus. Although previous studies have shown that heavy drinking frequently leads to the generation of IgA antibodies against neo-antigens induced by ethanol metabolites and tissue deposition of IgAs, the associations between alcohol consumption, IgA immune responses, and kidney disease have not been examined. METHODS A total of 158 IgAGN patients (96 men, 62 women) were classified as abstainers (n = 38), moderate drinkers (n = 114), and heavy drinkers (n = 6) based on self-reported alcohol consumption. The reference population included 143 individuals (99 men, 44 women) who were either apparently healthy abstainers (n = 31), moderate drinkers (n = 43), or heavy drinkers devoid of liver disease (n = 69). The assessments included various biomarkers of alcohol consumption: carbohydrate-deficient transferrin (CDT), glutamyl transferase, gamma-CDT (combination of GGR and CDT), mean corpuscular volume (MCV), tests for liver and kidney function, serum immunoglobulin A (IgA), and specific IgA antibodies against acetaldehyde-protein adducts. RESULTS In male IgAGN patients, drinking status was significantly associated with MCV, p < 0.001; CDT, p < 0.01; and gamma -CDT, p < 0.05. In the reference population, all biomarkers and anti-adduct IgA levels were found to vary according to drinking status. In IgAGN patients, anti-adduct IgA levels were elevated in 63% of the cases but the titers did not associate with self-reported ethanol intake. CONCLUSIONS These data indicate high levels of IgA antibodies against acetaldehyde-derived antigens in IgAGN patients, which may hamper the use of the immune responses as markers of alcohol consumption among such patients. Future studies on the pathogenic and prognostic significance of anti-adduct immune responses in IgAGN patients are warranted.
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Affiliation(s)
- Kati Kaartinen
- Department of Laboratory Medicine and Medical Research Unit, Medical School, University of Tampere, Tampere, Finland
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4
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Vidali M, Hietala J, Occhino G, Ivaldi A, Sutti S, Niemelä O, Albano E. Immune responses against oxidative stress-derived antigens are associated with increased circulating tumor necrosis factor-alpha in heavy drinkers. Free Radic Biol Med 2008; 45:306-11. [PMID: 18460346 DOI: 10.1016/j.freeradbiomed.2008.04.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/26/2008] [Accepted: 04/08/2008] [Indexed: 12/12/2022]
Abstract
Growing evidence indicates that pro-inflammatory cytokines play a key role in alcoholic liver disease (ALD). This study investigates whether immune response toward oxidative stress-derived antigens could be involved in promoting cytokine production in alcohol abusers. Cytokine profile and circulating IgG against human serum albumin modified by malondialdehyde (MDA-HSA) and against oxidized cardiolipin (Ox-CL) were evaluated in 59 heavy drinkers (HD) with (n=30) or without (n=29) ALD and 34 healthy controls. IgG against MDA-HSA and Ox-CL were significantly higher in HD with ALD than in HD without liver injury or healthy controls. The elevation of these antibodies was associated with higher circulating levels of IL-2 (p=0.005) and TNF-alpha (p=0.001), but not of IL-6 or IL-8. The prevalence of abnormal TNF-alpha was 5-fold higher in HD with oxidative stress-induced IgG than in those without. HD with the combined elevation of both TNF-alpha and oxidative stress-induced IgG had 11-fold (OR 10.7; 95%CI 1.2-97.2; p=0.023) greater risk of advanced ALD than those with high TNF-alpha, but no immune responses. Moreover, the combined elevation of TNF-alpha and lipid peroxidation-derived IgG was an independent predictor of ALD in HD. We propose that immune responses towards oxidative stress-derived antigen promote TNF-alpha production and contribute to liver damage in alcohol abusers.
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Affiliation(s)
- Matteo Vidali
- Department of Medical Sciences and Interdepartmental Research Centre for Autoimmune Diseases , University Amedeo Avogadro of East Piedmont, Via Solaroli 17, 28100 Novara, Italy
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5
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Neuropathology of alcohol-related cognitive alterations. HANDBOOK OF CLINICAL NEUROLOGY 2008. [PMID: 18631801 DOI: 10.1016/s0072-9752(07)01275-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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6
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Abstract
Patterns of drinking are changing throughout the world and in many countries this will be detrimental to the health and welfare of the local population. Even uncomplicated alcoholics who have no specific neurological or hepatic problems show signs of regional brain damage and cognitive dysfunction. Many of these changes are exaggerated and other brain regions damaged in patients who have additional vitamin B1 (thiamine) deficiency (Wernicke-Korsakoff syndrome). Quantitative neuropathology techniques and improvements in neuroimaging have contributed significantly to the documentation of these changes but mechanisms underlying the damage are not understood. A human brain bank targeting alcohol cases has been established in Sydney, Australia and provides fresh and frozen tissue for alcohol researchers. The tissues can be used to test hypotheses developed from structural neuropathological studies or from animal models and in vitro studies. Identification of reversible pathological changes and preventative medical approaches in alcoholism should enhance rehabilitation and treatment efforts, thereby mitigating debilitating morbidities and reducing mortality associated with this universal public health problem.
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Affiliation(s)
- Clive Harper
- Department of Pathology, Blackburn Building, D06, University of Sydney, NSW 2006, Australia.
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Strolin Benedetti M, Whomsley R, Baltes E. Involvement of enzymes other than CYPs in the oxidative metabolism of xenobiotics. Expert Opin Drug Metab Toxicol 2007; 2:895-921. [PMID: 17125408 DOI: 10.1517/17425255.2.6.895] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although the majority of oxidative metabolic reactions are mediated by the CYP superfamily of enzymes, non-CYP-mediated oxidative reactions can play an important role in the metabolism of xenobiotics. The (major) oxidative enzymes, other than CYPs, involved in the metabolism of drugs and other xenobiotics are: the flavin-containing monooxygenases, the molybdenum hydroxylases (aldehyde oxidase and xanthine oxidase), the prostaglandin H synthase, the lipoxygenases, the amine oxidases (monoamine, polyamine, diamine and semicarbazide-sensitive amine oxidases) and the alcohol and aldehyde dehydrogenases. In a similar manner to CYPs, these oxidative enzymes can also produce therapeutically active metabolites and reactive/toxic metabolites, modulate the efficacy of therapeutically active drugs or contribute to detoxification. Many of them have been shown to be important in endobiotic metabolism, and, consequently, interactions between drugs and endogenous compounds might occur when they are involved in drug metabolism. In general, most non-CYP oxidative enzymes appear to be noninducible or much less inducible than the CYP system, although some of them may be as inducible as some CYPs. Some of these oxidative enzymes exhibit polymorphic expression, as do some CYPs. It is possible that the contribution of non-CYP oxidative enzymes to the overall metabolism of xenobiotics is underestimated, as most investigations of drug metabolism in discovery and lead optimisation are performed using in vitro test systems optimised for CYP activity.
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Nakamura K, Iwahashi K, Itoh M, Ameno K, Ijiri I, Takeuchi Y, Suwaki H. Immunohistochemical Study on Acetaldehyde Adducts in Alcohol-Fed Mice. Alcohol Clin Exp Res 2006. [DOI: 10.1111/j.1530-0277.2000.tb00020.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kazuhiko Nakamura
- Department of Neuropsychiatry; Azabu University; Sagamihara-city Kanagawa Japan
| | - Kazuhiko Iwahashi
- Department of Neuropsychiatry; Azabu University; Sagamihara-city Kanagawa Japan
| | - Masahiro Itoh
- Department of Anatomy; Azabu University; Sagamihara-city Kanagawa Japan
| | - Kiyoshi Ameno
- Department of Forensic Medicine, Faculty of Medicine; Kagawa Medical University, Miki-cho; Kita-gun Kagawa Japan
| | - Iwao Ijiri
- Department of Forensic Medicine, Faculty of Medicine; Kagawa Medical University, Miki-cho; Kita-gun Kagawa Japan
- Health Administration Center; Azabu University; Sagamihara-city Kanagawa Japan
| | - Yoshiki Takeuchi
- Department of Anatomy; Azabu University; Sagamihara-city Kanagawa Japan
| | - Hiroshi Suwaki
- Department of Neuropsychiatry; Azabu University; Sagamihara-city Kanagawa Japan
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9
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Abstract
Although alcohol abuse is known to cause a wide array of adverse effects on blood cell formation, the molecular mechanisms by which alcohol exerts its toxic actions have remained poorly defined. Elevated mean corpuscular volume (MCV), macrocytosis, is the most typical morphological abnormality induced by excessive ethanol consumption. This paper reviews recent data indicating that acetaldehyde, the first metabolite of ethanol, may play a role in the haematological derangements in peripheral blood cells and in bone marrow of alcoholic patients. Studies in experimental animals and in human alcoholics have shown that acetaldehyde can bind to proteins and cellular constituents forming stable adducts. Elevated adduct levels have been found from the erythrocytes of alcohol abusers, which may also be associated with ethanol-induced effects in haematopoiesis and adverse consequences in cellular functions.
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Affiliation(s)
- Onni Niemelä
- EP Central Hospital, Laboratory and the Department of Clinical Chemistry, and Institute of Medical Technology, University of Tampere, Finland.
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Aberle NS, Ren J. Short-Term Acetaldehyde Exposure Depresses Ventricular Myocyte Contraction: Role of Cytochrome P450 Oxidase, Xanthine Oxidase, and Lipid Peroxidation. Alcohol Clin Exp Res 2003. [DOI: 10.1111/j.1530-0277.2003.tb04393.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Shimada S, Yamauchi M, Takamatsu M, Uetake S, Ohata M, Saito S. Experimental studies on the relationship between immune responses and liver damage induced by ethanol after immunization with homologous acetaldehyde adducts. Alcohol Clin Exp Res 2003. [PMID: 12198382 DOI: 10.1111/j.1530-0277.2002.tb02709.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND It has been considered that acetaldehyde (AcH) adducts induce liver injury through an immune response. Previous experimental studies showed that hepatic necrosis, inflammatory cell infiltration, and hepatic fibrosis were induced in guinea pigs immunized with heterologous human AcH adducts and ethanol feeding. AcH modification of foreign protein may markedly increase immunogenicity of the protein itself, leading to enhanced formation of immune complex and possible liver injury. The present study investigated whether immune responses and alcoholic liver disease would be induced in mice by immunization with mouse albumin-AcH adducts and ethanol feeding. METHODS 6B6 mice were divided into six groups with or without immunization and ethanol feeding. Mice were immunized with mouse albumin-AcH adducts three times at 2-week intervals and fed ethanol for 10 weeks. The stimulation index of [(3)H]thymidine uptake into lymphocytes cultured with mouse albumin or mouse albumin-AcH adducts was measured. Histologic findings of the liver were examined, and the plasma levels of aspartate transaminase and alanine aminotransferase were also measured. RESULTS The stimulation index was increased remarkably in ethanol-fed mice that were immunized with mouse albumin-AcH adducts. However, neither inflammatory cell infiltration nor hepatic necrosis was observed in the liver. There were also no differences in the plasma activities of aspartate transaminase and alanine aminotransferase between the group of mice regardless of ethanol feeding or immunization. CONCLUSION Although marked immune responses were observed, no liver damage was induced by long-term ethanol feeding in our mouse model using AcH-homologous albumin adducts. These results suggest that homologous protein adducts may not induce liver injury by long-term ethanol feeding or may have lower immunogenicity than heterologous protein adducts. These results also suggest that nonreduced AcH adducts and/or a larger amount of ethanol may be needed for liver injury in this model.
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Affiliation(s)
- Seika Shimada
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan
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12
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Abstract
The cause of alcoholic liver disease (ALD) is multifactorial and poorly understood. It is clear that alcohol alone is not responsible for most of the changes associated with ALD and that cofactors are involved in initiation and production of ALD. One cofactor that has received a great deal of attention recently is the concomitant infection with hepatitis C virus (HCV) and alcohol abuse. The interactive effects of HCV and alcohol abuse are still unclear, but apparently they are the result of an inability of the immune system to control the viral infection and exaggerated hepatocyte damage mediated by either the cells of the inflammatory response or factors produced by the inflammatory cells. This review will focus on one aspect of the possible pathogenic effects associated with alcohol abuse and HCV infection: the possible role of the immune system, notably the cytotoxic T lymphocyte (CTL) response. It is clear that the development of a CTL response is critical for the control of HCV infections, and it is also likely that this response is involved in liver damage. In this review, the evidence that shows the importance of the CD8(+) CTL in viral clearance and the role for pathogenesis will be presented. Findings obtained from animal studies that support the suggestion that activated CD8(+) CTLs can induce liver damage will be presented, as will results of recent studies from my laboratory that provide evidence for an effect of alcohol to enhance the liver damage mediated by activated CD8(+) T cells.
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Affiliation(s)
- Thomas R Jerrells
- Department of Pathology and Microbiology, University of Nebraska Medical Center and Omaha VA Medical Center, Omaha, NE 68105, USA.
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Duan J, McFadden GE, Borgerding AJ, Norby FL, Ren BH, Ye G, Epstein PN, Ren J. Overexpression of alcohol dehydrogenase exacerbates ethanol-induced contractile defect in cardiac myocytes. Am J Physiol Heart Circ Physiol 2002; 282:H1216-22. [PMID: 11893554 DOI: 10.1152/ajpheart.00780.2001] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Alcoholic cardiomyopathy is characterized by impaired ventricular function although its toxic mechanism is unclear. This study examined the impact of cardiac overexpression of alcohol dehydrogenase (ADH), which oxidizes ethanol into acetaldehyde (ACA), on ethanol-induced cardiac contractile defect. Mechanical and intracellular Ca(2+) properties were evaluated in ventricular myocytes from ADH transgenic and wild-type (FVB) mice. ACA production was assessed by gas chromatography. ADH myocytes exhibited similar mechanical properties but a higher efficiency to convert ACA compared with FVB myocytes. Acute exposure to ethanol depressed cell shortening and intracellular Ca(2+) in the FVB group with maximal inhibitions of 23.3% and 23.4%, respectively. Strikingly, the ethanol-induced depression on cell shortening and intracellular Ca(2+) was significantly augmented in the ADH group, with maximal inhibitions of 43.7% and 40.6%, respectively. Pretreatment with the ADH inhibitor 4-methylpyrazole (4-MP) or the aldehyde dehydrogenase inhibitor cyanamide prevented or augmented the ethanol-induced inhibition, respectively, in the ADH but not the FVB group. The ADH transgene also substantiated the ethanol-induced inhibition of maximal velocity of shortening/relengthening and unmasked an ethanol-induced prolongation of the duration of shortening/relengthening, which was abolished by 4-MP. These data suggest that elevated cardiac ACA exposure due to enhanced ADH expression may play an important role in the development of alcoholic cardiomyopathy.
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Affiliation(s)
- Jinhong Duan
- Department of Pharmacology, Physiology, and Therapeutics, Grand Forks, North Dakota 58203, USA
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Wang K, Busker-Mannie AE, Hoeft J, Vasquez K, Miller SD, Melvold RW, Waltenbaugh C. Prolonged Hya-Disparate Skin Graft Survival in Ethanol-Consuming Mice: Correlation With Impaired Delayed Hypersensitivity. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02158.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Homann N. Alcohol and upper gastrointestinal tract cancer: the role of local acetaldehyde production. Addict Biol 2001; 6:309-323. [PMID: 11900609 DOI: 10.1080/13556210020077028] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alcohol is, together with tobacco smoke, the main cause for upper GI tract cancer in industrialized countries. However, the tumour-promoting effects of alcohol intake are poorly understood and alcohol itself is not carcinogenic in the animal model. There is increasing evidence that alcohol metabolism, rather than the alcohol itself, generates carcinogenic and cell-toxic compounds. Acetaldehyde, first metabolite of ethanol, is highly toxic, mutagenic and carcinogenic. Polymorphisms in the genes coding for enzymes responsible for acetaldehyde accumulation and detoxification have been associated with an increased cancer risk. Acetaldehyde can also be produced in the mucosa and by the physiological microflora. This review summarizes the scientific evidence that alcohol intake leads to a local production of acetaldehyde. It describes the role of the oral microflora, the mucosa and the salivary glands in this process and shows that local acetaldehyde production from ethanol may contribute to the carcinogenesis of alcohol intake in the upper GI tract.
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Affiliation(s)
- Nils Homann
- Department of Gastroenterology, Medical University of Luebeck, Germany
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Slukvin II, Boor PJ, Jerrells TR. Initiation of alcoholic fatty liver and hepatic inflammation with a specific recall immune response in alcohol-consuming C57Bl/6 mice. Clin Exp Immunol 2001; 125:123-33. [PMID: 11472435 PMCID: PMC1906099 DOI: 10.1046/j.1365-2249.2001.01529.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Whether immunological responses are involved in initiation and progression of alcoholic liver disease is unclear. We describe a mouse model of alcoholic liver injury characterized by steatosis and hepatic inflammation initiated by a recall immune response. Mice immune to Listeria monocytogenes fed a liquid diet containing ethanol and challenged with viable bacteria developed steatosis within 24 h and, at a later time, elevated serum alanine aminotransferase levels, indicating more liver damage in this group. Listeria antigen also induced steatosis and increased serum alanine aminotransferase levels in immune ethanol-consuming mice. The production of tumour necrosis factor by a recall immune response in this model is a major, but not the only, component in initiation of alcoholic liver disease.
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Affiliation(s)
- I I Slukvin
- Department of Cellular Biology and Anatomy, Louisiana State University Medical Center, Shreveport, LA, USA
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Viitala K, Makkonen K, Israel Y, Lehtimäki T, Jaakkola O, Koivula T, Blake JE, Niemelä O. Autoimmune responses against oxidant stress and acetaldehyde-derived epitopes in human alcohol consumers. Alcohol Clin Exp Res 2000. [PMID: 10924016 DOI: 10.1111/j.1530-0277.2000.tb04656.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Studies in experimental animals have indicated that chronic ethanol ingestion triggers the formation of antibodies directed against proteins modified with reactive metabolites of ethanol and products of lipid peroxidation. However, the nature and prevalence of such antibodies have not been compared previously in alcoholic patients. METHODS Autoantibodies against adducts with acetaldehyde- (AA), malondialdehyde- (MDA), and oxidized epitopes (Ox) were examined from sera of 54 alcohol consumers with (n = 28) or without (n = 26) liver disease, and from 20 nondrinking controls. RESULTS Anti-AA-adduct IgA and IgG antibodies were elevated in 64% and 31% of patients with biopsy-proven alcoholic liver disease (ALD, n = 28), respectively. The IgA titers were significantly higher than those from nondrinking controls (p < 0.001), or heavy drinkers without significant liver disease (p < 0.001). Anti-MDA adduct titers (IgG) were elevated in 70% of the ALD patients. These titers were significantly higher (p < 0.001) than those from nondrinking controls, or heavy drinkers without liver disease. Antibodies (IgG) against Ox epitopes occurred in 43% of ALD patients, and the titers also were significantly higher (p < 0.05) than those from nondrinking controls. The anti-AA and anti-MDA adduct titers in ALD patients correlated significantly with the combined clinical and laboratory index (CCLI) of liver disease severity (r(s) = 0.449, p < 0.05; r(s) = 0.566, p < 0.01, respectively), the highest prevalences of anti-AA-adducts (73%) and anti-MDA-adducts (76%) occurring in ALD patients with cirrhosis. CONCLUSIONS The present results indicated that autoantibodies against several distinct types of protein modifications are generated in ALD patients showing an association with the severity of liver disease.
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Affiliation(s)
- K Viitala
- EP Central Hospital Laboratory, Seinäjoki, Finland
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Rosman AS, Waraich A, Baraona E, Lieber CS. Disulfiram Treatment Increases Plasma and Red Blood Cell Acetaldehyde in Abstinent Alcoholics. Alcohol Clin Exp Res 2000. [DOI: 10.1111/j.1530-0277.2000.tb04637.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rolla R, Vay D, Mottaran E, Parodi M, Traverso N, Aricó S, Sartori M, Bellomo G, Klassen LW, Thiele GM, Tuma DJ, Albano E. Detection of circulating antibodies against malondialdehyde-acetaldehyde adducts in patients with alcohol-induced liver disease. Hepatology 2000; 31:878-84. [PMID: 10733543 DOI: 10.1053/he.2000.5373] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Acetaldehyde and malonildialdehyde can form hybrid protein adducts, named MAA adducts that have strong immunogenic properties. The formation of MAA adducts in the liver of chronic alcohol-fed rats is associated with the development of circulating antibodies that specifically recognized these adducts. The aim of this study was to examine whether MAA adducts might participate in the immune response associated with human alcohol-induced liver disease. Circulating antibodies against MAA adducts were evaluated in 50 patients with alcohol-induced hepatitis or cirrhosis, in 40 patients with non-alcohol-induced liver disease, in 15 heavy drinkers without liver damage and in 40 healthy controls by enzyme-linked immunosorbent assays (ELISA). Immunoglobulin G (IgG) reacting with MAA-modified proteins were significantly increased in the patients with alcohol-induced cirrhosis or hepatitis. The individual levels of anti-MAA IgG in those patients were associated with the severity of liver damage. Anti-MAA antibodies were also positively correlated with the levels of IgG recognizing epitopes generated by acetaldehyde and malonildialdehyde. However, competitive inhibition experiments indicated that the anti-MAA antibodies were unrelated to those against acetaldehyde- or malonildialdehyde-derived antigens and mainly recognized a specific, cyclic MAA epitope. Some degree of immune reactivity towards MAA adducts was also observed in patients with non-alcohol-induced liver injury. However, competitive ELISA showed that the antigens recognized by these sera were not the cyclic MAA adducts. Altogether, these results showed the formation of MAA antigens during alcohol-induced liver disease and suggest their possible contribution to the development of immunologic reactions associated with alcohol-related liver damage.
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Affiliation(s)
- R Rolla
- Department of Medical Sciences, University "Amedeo Avogadro" of East Piedmont, Novara, Italy
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Nagata N, Watanabe N, Tsuda M, Tsukamoto H, Matsuzaki S. Relationship between serum levels of anti-low-density lipoprotein-acetaldehyde-adduct antibody and aldehyde dehydrogenase 2 heterozygotes in patients with alcoholic liver injury. Alcohol Clin Exp Res 1999; 23:24S-28S. [PMID: 10235274 DOI: 10.1111/j.1530-0277.1999.tb04529.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We prepared low-density lipoprotein (LDL)-acetaldehyde-adduct (hereafter abbreviated as LDL-adduct) and anti-LDL-adduct antibody by using Watanabe hyperlipidemic rabbits, and determined values of serum anti-LDL-adduct antibody levels by the ELISA method in healthy adults and patients with alcoholic liver injury. In the nondrinking group in healthy adults, values of anti-LDL-adduct antibody levels were 25 +/- 13 microg/ml, and there was no significant difference between moderate drinkers without diseases and the nondrinking group in healthy adults. Values of anti-LDL-adduct antibody in alcoholic disease groups, 17 +/- 9 microg/ml for the patients with the fatty liver group, 21 +/- 14 microg/ml for the hepatic fibrosis group, 70 +/- 21 microg/ml for the alcoholic hepatitis group, 41 +/- 50 microg/ml for the alcoholic cirrhosis group, and 19 +/- 18 microg/ml for the alcoholic pancreatitis group. Examinations of aldehyde dehydrogenase 2 (ALDH2) genetic variations by the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) method in the healthy group and the liver injury group revealed a tendency for patients with ALDH2(1)/2(2) in the liver injury group to have relatively mild liver lesions. When comparing anti-LDL-adduct antibody levels between ALDH2 genetic variations, those for the patients with ALDH2(1)/2(2) (36 +/- 40 microg/ml) were significantly higher than those for patients with ALDH2(1)/2(2) (11 +/- 5 microg/ml). Results of the present study suggest that genetic variation may influence the progression of liver injury.
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MESH Headings
- Acetaldehyde/blood
- Acetaldehyde/immunology
- Adult
- Aged
- Aged, 80 and over
- Aldehyde Dehydrogenase/genetics
- Aldehyde Dehydrogenase, Mitochondrial
- Animals
- Autoantibodies/blood
- Ethanol/administration & dosage
- Fatty Liver, Alcoholic/enzymology
- Fatty Liver, Alcoholic/genetics
- Fatty Liver, Alcoholic/immunology
- Female
- Hepatitis, Alcoholic/enzymology
- Hepatitis, Alcoholic/genetics
- Hepatitis, Alcoholic/immunology
- Heterozygote
- Humans
- Lipoproteins, LDL/blood
- Lipoproteins, LDL/immunology
- Liver Cirrhosis, Alcoholic/genetics
- Liver Cirrhosis, Alcoholic/immunology
- Liver Diseases, Alcoholic/enzymology
- Liver Diseases, Alcoholic/genetics
- Liver Diseases, Alcoholic/immunology
- Male
- Middle Aged
- Polymerase Chain Reaction
- Polymorphism, Single-Stranded Conformational
- Rabbits
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Affiliation(s)
- N Nagata
- Department of Internal Medicine, School of Medicine, Tokai University, Isehara, Kanagawa, Japan
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22
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Klassen LW, Jones BL, Sorrell MF, Tuma DJ, Thiele GM. Conversion of Acetaldehyde-Protein Adduct Epitopes From a Nonreduced to a Reduced Phenotype by Antigen Processing Cells. Alcohol Clin Exp Res 1999. [DOI: 10.1111/j.1530-0277.1999.tb04167.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Moncada C, Israel Y. Generation of acetate and production of ethyl-lysine in the reaction of acetaldehyde plus serum albumin. Alcohol 1999; 17:87-91. [PMID: 9895041 DOI: 10.1016/s0741-8329(98)00037-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report that incubation of acetaldehyde with bovine serum albumin results in the generation of acetate in a reaction that is directly proportional to the levels of albumin and exponentially dependent on the concentration of acetaldehyde. Both reactants need to be present for acetate to be formed. The oxidation of acetaldehyde into acetate requires that a reduced product also be generated in the reaction. It was hypothesized that, at high concentrations, acetaldehyde itself may reduce the Schiff bases formed in the reaction of a second molecule of acetaldehyde with amino groups in the protein, resulting in the generation of ethyl-lysine moieties. Incubation of acetaldehyde (240 mM) with bovine serum albumin was found to generate ethyl-lysine moieties as determined by a specific monoclonal antibody. Immunization of rabbits with products of the reaction of bovine serum albumin with acetaldehyde led to the generation of antibodies that reacted to reduced adducts formed in the reaction of acetaldehyde and proteins in the presence of sodium cyanoborohydride. However, the generation of acetate from acetaldehyde plus albumin was 60-fold greater than could be explained by the reduction of Schiff bases, as determined by the maximal incorporation of [14C]-acetaldehyde into an acid-precipitable protein fraction. Thus, other mechanisms to generate acetate also occur. The present findings provide an explanation for earlier reports that acetaldehyde adducts formed under "nonreducing" conditions generate antibodies that recognize reduced acetaldehyde protein adducts. However, the mechanism by which the bulk of acetate is generated in the reaction of acetaldehyde and bovine serum albumin remains to be elucidated.
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Affiliation(s)
- C Moncada
- Department of Pharmacology and Toxicology and Center for Gene Pharmacotherapy, University of Chile, Santiago.
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24
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Xu D, Thiele GM, Beckenhauer JL, Klassen LW, Sorrell MF, Tuma DJ. Detection of circulating antibodies to malondialdehyde-acetaldehyde adducts in ethanol-fed rats. Gastroenterology 1998; 115:686-92. [PMID: 9721166 DOI: 10.1016/s0016-5085(98)70148-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Malondialdehyde and acetaldehyde react together with proteins and form hybrid protein conjugates designated as MAA adducts, which have been detected in livers of ethanol-fed rats. The aim of this study was to examine the immune response to MAA adducts and other aldehyde adducts during long-term ethanol exposure. METHODS Rats were pair-fed for 7 months with a liquid diet containing either ethanol or isocaloric carbohydrate. Circulating antibody titers against MAA adducts and acetaldehyde adducts were measured and characterized in these animals. RESULTS A significant increase in antibody titers against MAA-adducted proteins was observed in the ethanol-fed animals. Competitive inhibitions of antibody binding indicated that the circulating antibodies against MAA-modified proteins in the ethanol-fed rats recognized mainly a specific, chemically defined MAA epitope. Antibody titers to reduced and nonreduced acetaldehyde adducts were very low, and no significant differences were observed between ethanol-fed and control animals. Significant plasma immunoreactivity to not only MAA-adducted but also unmodified rat liver proteins (cytosol, microsomes, and especially plasma membrane) were also observed in the ethanol-fed rats. CONCLUSIONS Long-term ethanol feeding generates circulating antibodies not only against MAA epitopes but possibly also against unmodified, native (self) protein epitopes, suggesting that MAA adducts could trigger harmful autoimmune responses.
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Affiliation(s)
- D Xu
- Department of Veterans Affairs Alcohol Research Center and Departments of Internal Medicine and Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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25
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Nagata N, Nishizaki Y, Watanabe N, Tsuda M, Matsuzaki S. An enzyme immune assay for serum anti-acetaldehyde adduct antibody using low-density lipoprotein adduct and its significance in alcoholic liver injury. Alcohol Clin Exp Res 1998; 22:150S-155S. [PMID: 9622394 DOI: 10.1111/acer.1998.22.s3_part1.150s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An acetaldehyde (AcH) adduct was prepared using rabbit low-density lipoprotein as carrier proteins. An antibody against this adduct was raised in Watanabe heritable hyperlipidemic rabbits and cross-reacted with human low-density lipoprotein and bovine serum albumin adducts. Using this antibody, serum anti-AcH-adduct antibody levels were measured by a direct ELISA method in 56 Japanese adults (healthy adults and patients with nonalcoholic gastrointestinal diseases, alcoholic liver injury, or alcoholic pancreatitis). The antibody level (mean +/- SD) was 22 +/- 10 microg/ml in healthy adults, 22 +/- 11 microg/ml in nonalcoholic gastrointestinal diseases, and 16 +/- 13 microg/ml in alcoholic pancreatitis. These antibody levels tended to increase with the progression of alcoholic liver injury, starting from fatty liver via hepatitis to cirrhosis, 29 +/- 24 microg/ml in fatty liver, 35 +/- 29 microg/ml in alcoholic hepatitis, and 46 +/- 54 microg/ml in alcoholic cirrhosis. The antibody level in patients taking 100 g or more of ethanol per day tended to be higher, compared with those in people taking less ethanol. A follow-up observation revealed that alcohol abstinence after hospitalization raised serum anti-AcH-adduct antibody level in some patients and kept it constantly low in other patients. The immunohistochemical study using the anti-AcH-adduct antibody revealed the presence of adduct-like substance in hepatocytes of liver biopsy specimens obtained from patients with alcoholic liver disease. The results indicate that the anti-AcH-adduct antibody may be associated with the progress of alcoholic liver diseases.
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Affiliation(s)
- N Nagata
- Third Department of Internal Medicine, School of Medicine, Tokai University, Kanagawa, Japan
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26
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Hill DB, Kugelmas M. Alcoholic liver disease. Treatment strategies for the potentially reversible stages. Postgrad Med 1998; 103:261-4, 267-8, 273-5. [PMID: 9553600 DOI: 10.3810/pgm.1998.04.462] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Even modest alcohol ingestion can increase the risk of steatosis, and long-term, excessive consumption can lead to alcoholic hepatitis and eventually cirrhosis. Most patients with clinically significant alcoholic liver disease have histologic findings typical of all three conditions. The only clearly beneficial treatment is abstinence from alcohol. Abstinence in combination with proper nutrition and general supportive care is state of the art. Steatosis is reversible upon withdrawal of alcohol, but alcoholic hepatitis can persist even with abstinence and may progress to cirrhosis. Corticosteroid therapy may reduce short-term mortality rates in patients with moderate or severe alcoholic hepatitis who have hepatic encephalopathy but no evidence of infection or gastrointestinal bleeding. Treatment with colchicine may decrease the risk of cirrhosis; however, once cirrhosis has developed, the liver damage is irreversible. The prognosis is improved with abstinence, but complications (e.g., ascites, gastrointestinal bleeding) often occur. Liver transplantation may be considered in patients with severe complications.
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Affiliation(s)
- D B Hill
- Division of Digestive Diseases and Nutrition, University of Kentucky College of Medicine, Lexington 40536-0084, USA.
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27
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Lieber CS, Leo MA. Metabolism of ethanol and some associated adverse effects on the liver and the stomach. RECENT DEVELOPMENTS IN ALCOHOLISM : AN OFFICIAL PUBLICATION OF THE AMERICAN MEDICAL SOCIETY ON ALCOHOLISM, THE RESEARCH SOCIETY ON ALCOHOLISM, AND THE NATIONAL COUNCIL ON ALCOHOLISM 1998; 14:7-40. [PMID: 9751941 DOI: 10.1007/0-306-47148-5_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
Current knowledge of alcohol oxidation and its effects on hepatic metabolism and its toxicity are summarized. This includes an evaluation of the relationship of the level of consumption to its interaction with nutrients (especially retinoids, carotenoids, and folate) and the development of various stages of liver disease. Ethanol metabolism in the stomach and its link to pathology and Helicobacter pylori is reviewed. Promising therapeutic approaches evolving from newly gained insight in the pathogenesis of medical complications of alcoholism are outlined. At present, the established approach for the prevention and treatment of alcoholism are outlined. At present, the established approach for the prevention and treatment of alcoholic liver injury is to control alcohol abuse, with the judicial application of selective antioxidant therapy, instituted at early stages, prior to the social or medical disintegration of the patient, and associated with antiinflammatory agents at the acute phase of alcoholic hepatitis. In addition, effective antifibrotic therapy may soon become available.
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Affiliation(s)
- C S Lieber
- Department of Medicine, Mount Sinai School of Medicine, New York, New York, USA
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28
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Ma X, Svegliati-Baroni G, Poniachik J, Baraona E, Lieber CS. Collagen synthesis by liver stellate cells is released from its normal feedback regulation by acetaldehyde-induced modification of the carboxyl-terminal propeptide of procollagen. Alcohol Clin Exp Res 1997. [PMID: 9347080 DOI: 10.1111/j.1530-0277.1997.tb04439.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Acetaldehyde stimulates collagen synthesis in stellate cells and forms adducts with procollagen in the liver of alcoholics. To assess the possibility that modification of the carboxyl-terminal propeptide by acetaldehyde affects its capacity to exert a feedback inhibition of collagen synthesis after splitting from procollagen, the propeptide was prepared by gel filtration of the bacterial collagenase digests of procollagen type I (obtained from 10(9) calvaria fibroblasts of newborn rats) and reacted with either 250 mM acetaldehyde and 100 mM CNBH3 or with 170 microM acetaldehyde without reducing agents, to mimick in vivo conditions. The unmodified propeptide produced a concentration-dependent inhibition of collagen synthesis by Ito cells. By contrast, the acetaldehyde-modified propeptide produced a lesser inhibition of procollagen synthesis in the cells, associated with a greater accumulation of collagen in the media. The incubation with 170 microM acetaldehyde and, to a lesser extent, 50 mM ethanol produced collagenase-digestible adducts in stellate cells. Thus, the formation of acetaldehyde adducts with the carboxyl-terminal propeptide of procollagen may account, at least in part, for the stimulatory effect of acetaldehyde on collagen synthesis by stellate cells and may lead to collagen accumulation through a decrease of the normal feedback regulation of collagen synthesis by the propeptide.
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Affiliation(s)
- X Ma
- Alcohol Research and Treatment Center, Bronx Veteran Affairs Medical Center, NY 10468, USA
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29
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Ishii H, Kurose I, Kato S. Pathogenesis of alcoholic liver disease with particular emphasis on oxidative stress. J Gastroenterol Hepatol 1997; 12:S272-82. [PMID: 9407347 DOI: 10.1111/j.1440-1746.1997.tb00510.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oxidative stress is well recognized to be a key step in the pathogenesis of ethanol-associated liver injury. Ethanol administration induces an increase in lipid peroxidation either by enhancing the production of oxygen reactive species and/or by decreasing the level of endogenous antioxidants. Numerous experimental studies have emphasized the role of the ethanol-inducible cytochrome P450 in the microsomes and the molybdo-flavoenzyme xanthine oxidase in the cytosol. This review shows the putative role of ethanol-induced disturbances in iron metabolism in relation to iron as a pro-oxidant factor. Ethanol administration also affects the mitochondrial free radical generation. Many previous studies suggest a role for active oxygens in ethanol-induced mitochondrial dysfunction in hepatocytes. Recent studies in our laboratory in the Department of Internal Medicine, Keio University, using a confocal laser scanning microscopic system strongly suggest that active oxidants generated during ethanol metabolism produce mitochondrial membrane permeability transition in isolated and cultured hepatocytes. In addition, acetaldehyde, ethanol consumption-associated endotoxaemia and subsequent release of inflammatory mediators may cause hepatocyte injury via both oxyradical-dependent and -independent mechanisms. These cytotoxic processes may lead to lethal hepatocyte injury. Investigations further implicate the endogenous glutathione-glutathione peroxidase system and catalase as important antioxidants and cytoprotective machinery in the hepatocytes exposed to ethanol.
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Affiliation(s)
- H Ishii
- Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan
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30
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Steinberg JJ, Oliver GW, Cajigas A. The formation and measurement of DNA neuroadduction in alcoholism. Case report. Am J Forensic Med Pathol 1997; 18:84-91. [PMID: 9095308 DOI: 10.1097/00000433-199703000-00016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We present a case report of an intoxicated alcoholic driver who sustained fatal motor vehicle injuries. We subsequently quantified ethanol-derived acetaldehyde (ACE) DNA products in his brain, which may represent a major contributor to clinical alcoholic use and complications. Further, ACE DNA neuroadducts may indicate chronic exposure to alcohol, as demonstrated by 32P-prelabeled DNA and two-dimensional thin-layer chromatography. ACE and other unknown neuroadducts were evident in the histologically normal frontal, parietal, and caudate lobes. DNA neuroadduct formation was extensive and similar in three separate brain regions with normal histology. Contributing neuroadduction by chronic drug abuse is also possible, though the deceased's terminal acute blood screens for recent drug abuse were negative. The mechanism of alcohol neurotoxicity remains unknown, but biochemical nonenzymatic changes of DNA at the nucleic acid level (adduct formation) can alter gene function and stability. DNA neuroadduct detection may represent an important determinant in quantifying neurotoxicity from drug abuse or alcoholism in the absence of history, the presence of negative blood, tissue, and urine assays for recent drug and alcohol use, and the absence of neuropathology.
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Affiliation(s)
- J J Steinberg
- Division of Autopsy Pathology, Jacobi Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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31
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Abstract
Many xenobiotics are metabolically activated to electrophilic intermediates that form covalent adducts with proteins; the mechanism of toxicity is either intrinsic or idiosyncratic in nature. Many intrinsic toxins covalently modify cellular proteins and somehow initiate a sequence of events that leads to toxicity. Major protein adducts of several intrinsic toxins have been identified and demonstrate significant decreases in enzymatic activity. The reactivity of intermediates and subcellular localization of major targets may be important in the toxicity. Idiosyncratic toxicities are mediated through either a metabolic or immune-mediated mechanism. Xenobiotics that cause hypersensitivity/autoimmunity appear to have a limited number of protein targets, which are localized within the subcellular fraction where the electrophile is produced, are highly substituted, and are accessible to the immune system. Metabolic idiosyncratic toxins appear to have limited targets and are localized within a specific subcellular fraction. Identification of protein targets has given us insights into mechanisms of xenobiotic toxicity.
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Affiliation(s)
- N R Pumford
- Division of Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA
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32
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Worrall S, de Jersey J, Wilce PA, Seppä K, Hurme L, Sillanaukee P. Relationship between alcohol intake and immunoglobulin a immunoreactivity with acetaldehyde-modified bovine serum albumin. Alcohol Clin Exp Res 1996; 20:836-40. [PMID: 8865957 DOI: 10.1111/j.1530-0277.1996.tb05260.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Acetaldehyde, the main metabolite of ethanol, is a highly reactive species that reacts with macromolecules to produce unstable and stable adducts. Acetaldehyde-modified proteins are immunogenic and have been detected in the liver and blood of alcoholics. Furthermore, antibodies reactive with acetaldehyde-modified proteins have been detected in the plasma of social drinkers and alcoholics. However, the class distribution of immunoglobulins reactive with modified proteins was different in the two groups, being predominantly immunoglobulin (Ig)M in social drinkers, but IgM and IgA in alcoholics. In this study, we demonstrate that heavy drinkers (alcohol intake > 130 g/week for females and 150 g/week for males) also exhibit IgA reactivity with acetaldehyde-modified proteins. The IgA adduct-specific reactivity (IgA reactivity with acetaldehyde-modified bovine serum albumin-reactivity with native bovine serum albumin) showed a moderate correlation with self-reported alcohol intake, but did not correlate with markers such as plasma transaminase, gamma-glutamyltransferase activity, or mean corpuscular volume. IgA adduct-specific reactivity had similar specificity to the conventional tests of alcohol abuse, but had higher sensitivity than the other tests, especially with heavy drinkers. Data presented herein demonstrate that elevated IgA reactivity with acetaldehyde-modified epitopes is associated with heavy drinking and is a potential marker for high alcohol intake.
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Affiliation(s)
- S Worrall
- Alcohol Research Unit, University of Queensland, Australia
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33
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Fowles LF, Beck E, Worrall S, Shanley BC, de Jersey J. The formation and stability of imidazolidinone adducts from acetaldehyde and model peptides. A kinetic study with implications for protein modification in alcohol abuse. Biochem Pharmacol 1996; 51:1259-67. [PMID: 8787540 DOI: 10.1016/0006-2952(95)02408-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The kinetics of the reaction of acetaldehyde (AcH) with the alpha-amino group of several di- and tripeptides to form 2-methylimidazolidin-4-one adducts were determined at pH 7, 4, 37 degrees C, using reverse phase HPLC to separate peptides from adducts. The imidazolidin-4-one structure of the adducts was confirmed by 13C NMR spectroscopy. The reaction of val-gly-gly with AcH was shown to follow second-order kinetics over a wide range of concentrations of both reactants, with k2 = 0.734 +/- 0.032 M(-1) min(-1). Under conditions similar to those in the liver of an alcoholic during chronic ethanol oxidation ([Ach]o = 50-910 microm; [free peptide alpha-amino groups]o = 1.5 mM), the reaction proceeded until effectively all of the AcH had been consumed. The side chain of the N-terminal amino acid was shown not to have a marked effect on the rate of imidazolidinone formation. The decomposition of the imidazolidinone adduct of val-gly-gly and AcH was observed at 60-100 degrees C. Extrapolation of an Arrhenius plot to 37 degrees C provided an estimate of K(obs) of 0.002 h-1 (t1/2 approximately 14 days). Based on these kinetic studies, it is concluded that imidazolidinone adducts of AcH with proteins may be present in the liver and, possibly, in the blood of alcoholics.
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Affiliation(s)
- L F Fowles
- Alcohol Research Unit, Department of Biochemistry, University of Queensland, Australia
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34
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Ethanol-Induced Hypertension: The Role of Acetaldehyde. DEVELOPMENTS IN CARDIOVASCULAR MEDICINE 1996. [DOI: 10.1007/978-1-4613-1235-2_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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35
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McMillen BA. Detection of antibodies against proteins modified by hydroxyethyl free radicals in patients with alcoholic cirrhosis. Alcohol 1996. [DOI: 10.1016/s0741-8329(96)90016-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Kervinen K, Hörkkö S, Beltz WF, Kesäniemi A. Modification of VLDL apoprotein B by acetaldehyde alters apoprotein B metabolism. Alcohol 1995; 12:189-94. [PMID: 7639949 DOI: 10.1016/0741-8329(94)00081-n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Acetaldehyde (AcA), the first metabolite in ethanol oxidation, is chemically highly reactive and forms adducts with proteins in alcoholics. We examined the effect of very low density lipoprotein (VLDL) apoprotein B (apoB) modification by AcA on the metabolism of apoB-containing lipoproteins [VLDL, intermediate density lipoprotein (IDL) and low density lipoprotein (LDL)]. VLDL-B was selectively radiolabelled with either 125I or 131I and modified with various AcA concentrations, and the preparation was injected into rabbits simultaneously with control-treated VLDL. AcA modification of VLDL-B reduced the fractional catabolic rates for VLDL-B, IDL-B, and LDL-B. The direct removal of VLDL-B from plasma was decreased, whereas the fraction of VLDL-B converted to IDL-B was increased. The effect of AcA modification on the overall fraction of VLDL converted to LDL was qualitatively heterogeneous: VLDL-B modification with 2.0 mM AcA reduced the fraction converted, whereas modification with 4.0 and 8.0 mM AcA increased it. The concentrations of AcA used were higher than those reported in blood after ethanol ingestion, but the experiments serve to test in qualitative terms the model of VLDL-B modification by AcA. The observed VLDL-B alteration by AcA in vivo in alcoholics is most likely to be close to the minor modification used here, thereby theoretically contributing to the low IDL and LDL levels observed in alcoholics.
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Affiliation(s)
- K Kervinen
- Department of Internal Medicine, University of Oulu, Finland
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37
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Clot P, Bellomo G, Tabone M, Aricò S, Albano E. Detection of antibodies against proteins modified by hydroxyethyl free radicals in patients with alcoholic cirrhosis. Gastroenterology 1995; 108:201-7. [PMID: 7806042 DOI: 10.1016/0016-5085(95)90025-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND/AIMS We have previously shown that hydroxyethyl free radicals produced during cytochrome P4502E1-mediated oxidation of ethanol covalently bind to microsomal proteins. The present study examined whether alkylation of proteins by hydroxyethyl radicals induces an immunologic response in alcoholic patients. METHODS A microplate enzyme-linked immunosorbent assay was developed using as antigen human serum albumin or bovine fibrinogen reacted with chemically produced hydroxyethyl radicals. RESULTS This assay showed that the sera of alcoholic cirrhotics contained both immunoglobulin (Ig) Gs and IgAs that recognized proteins modified by hydroxyethyl radicals, whereas practically no reaction was observed in the sera of healthy controls or cirrhotics without evidence of alcohol abuse. The reactivity of the sera from alcoholic patients was not influenced by the protein to which hydroxyethyl radicals were bound. The sera of alcoholic cirrhotics also contained antibodies directed against acetaldehyde-modified albumin. However, the reaction of alcoholic sera with hydroxyethyl radical epitopes was not inhibited by increasing concentrations of acetaldehyde-modified albumin produced under either reducing or nonreducing conditions. CONCLUSIONS The results indicate that a new group of antigens that do not cross-react with antibodies against acetaldehyde-derived epitopes is formed by the alkylation of protein by hydroxyethyl radicals and is involved in the development of immunologic reactions in alcoholic patients.
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Affiliation(s)
- P Clot
- Department of Medical Sciences, Second Faculty of Medicine, University of Torino, Novara, Italy
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38
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Chedid A, Chadalawada KR, Morgan TR, Moritz TE, Mendenhall CL, Hammond JB, Emblad PW, Cifuentes DC, Kwak JW, Gilman-Sachs A. Phospholipid antibodies in alcoholic liver disease. Hepatology 1994; 20:1465-71. [PMID: 7982646 DOI: 10.1002/hep.1840200614] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Alcoholic liver injury has been reported to be directed preferentially against the proteins of the cell membrane, sparing the phospholipids. However, antiphospholipid antibodies against certain cell membrane phospholipids are known to be associated with a variety of diseases. We undertook this investigation to determine whether antiphospholipid antibodies were present in the serum of patients with alcoholic liver disease. We investigated seventy long-term alcoholic patients (> 80 gm ethanol/day for > 1 yr) and 8 normal nonalcoholic controls by means of enzyme-linked immunosorbent assay to determine whether serum antibodies were generated against the following membrane phospholipids: phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol (cardiolipin) and phosphatidic acid. Group 1 comprised alcoholic patients with normal liver function (n = 13), group 2 comprised alcoholic patients with abnormal liver function (n = 16), group 3 comprised patients with alcoholic hepatitis or cirrhosis (n = 41) and group 4 comprised nonalcoholic controls (n = 8). The antibody prevalence was 15% in group 1, 31% in group 2, 81% in group 3 and 0% in group 4. In group 3, 20 of 41 patients had antibodies against several cell membrane phospholipids (i.e., phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, phosphatidic acid, cardiolipin and phosphatidylinositol). The antiphosphatidylethanolamine isotype was IgA or IgM in 25 of 41 of these patients. Both IgA (p < 0.01) and IgM (p < 0.008) antiphosphatidylethanolamine correlated significantly with disease severity. Antiphospholipid antibodies in alcoholic patients seem to reflect disease progression and correlate significantly with disease severity.
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Affiliation(s)
- A Chedid
- Department of Pathology, Chicago Medical School, Illinois 60064
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39
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Thiele GM, Wegter KM, Sorrell MF, Tuma DJ, McDonald TL, Klassen LW. Specificity of N-ethyl lysine of a monoclonal antibody to acetaldehyde-modified proteins prepared under reducing conditions. Biochem Pharmacol 1994; 48:183-9. [PMID: 8043021 DOI: 10.1016/0006-2952(94)90238-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A monoclonal antibody has been developed that recognizes only protein-acetaldehyde (AA) adducts prepared under reducing conditions: 5 mM AA with 30 mM sodium cyanoborohydride overnight at 37 degrees. This monoclonal antibody is a mouse IgG2b that has been designated RT1.1. The primary adduct formed when proteins are exposed to acetaldehyde under reducing conditions is N-ethyl lysine (NEL). To examine the epitope specificity of RT1.1, inhibition ELISAs were developed using NEL and other possible inhibitors, such as arginine, ethylamine, lysine and proteins modified with AA under non-reducing conditions. RT1.1 (at half-maximum optical density, 50 ng/mL) was inhibited only by NEL and was independent of the carrier or the pH of the buffer used in the ELISA. Further evidence indicating that NEL is the epitope recognized by RT1.1 was obtained using mouse and human epidermal growth factor (EGF). Both proteins contain one alpha amino group but only the human-EGF contains lysine residues with epsilon amino groups. In experiments where these two proteins were modified with AA under reducing conditions, RT1.1 reacted only with human-EGF. These studies demonstrate that RT1.1 is specific for NEL that is formed by the ethylation of proteins with acetaldehyde under reducing conditions. Additionally, these studies demonstrate that the procedures and methods used herein may be useful for characterizing other antibodies prepared to AA-modified proteins under a variety of defined in vitro chemical conditions.
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Affiliation(s)
- G M Thiele
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha 68198
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Svegliati-Baroni G, Baraona E, Rosman AS, Lieber CS. Collagen-acetaldehyde adducts in alcoholic and nonalcoholic liver diseases. Hepatology 1994. [PMID: 7912686 DOI: 10.1002/hep.1840200118] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Alcoholic and, to a lesser extent, nonalcoholic patients with liver disease have serum antibodies to acetaldehyde-protein adducts produced in vitro. These antibodies presumably reflect the presence of adducts in the liver, but the protein that triggers this immune response has not been identified. To study this, we measured the reactivity of cytosolic proteins to rabbit IgG developed against a P-450 2E1-acetaldehyde adduct, isolated from alcohol-fed rats, that recognizes acetaldehyde-modified epitopes in proteins. Adducts were determined on Western blots by scanning densitometry of antibody-linked alkaline phosphatase activity in 4 normal livers and in needle biopsy specimens from subjects with liver disease, 17 alcoholic and 14 nonalcoholic. In all livers, except for a normal one, we found a reactive protein of at least 200 kD, similar to the collagen-acetaldehyde adduct we reported to be markedly increased in rats with experimentally induced cirrhosis. The immunostaining intensity in the alcoholic patients with liver disease was eightfold (p < 0.01) and that in nonalcoholic patients with liver disease was fourfold, greater (p < 0.02) than the weak staining in normal livers; it correlated with the degree of inflammation and serum AST or gamma-glutamyl transpeptidase activities. The adduct was reproduced on incubation of normal cytosolic proteins with 2.5 mmol/L acetaldehyde, whereas higher concentrations yielded many additional adducts; the adduct also reacted with IgG antibody to rat collagen type I and disappeared after digestion with collagenase, suggesting that the target protein is a form of collagen.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G Svegliati-Baroni
- Alcohol Research and Treatment Center, Bronx Veterans Affairs Medical Center, New York 10468
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Abstract
This article reviews current concepts on the pathogenesis and treatment of alcoholic liver disease. It has been known that the hepatotoxicity of ethanol results from alcohol dehydrogenase-mediated excessive generation of hepatic nicotinamide adenine dinucleotide, reduced form, and acetaldehyde. It is now recognized that acetaldehyde is also produced by an accessory (but inducible) microsomal pathway that additionally generates oxygen radicals and activates many xenobiotics to toxic metabolites, thereby explaining the increased vulnerability of heavy drinkers to industrial solvents, anesthetics, commonly used drugs, over-the-counter medications, and carcinogens. The contribution of gastric alcohol dehydrogenase to the first-pass metabolism of ethanol and alcohol-drug interactions is discussed. Roles for hepatitis C, cytokines, sex, genetics, and age are now emerging. Alcohol also alters the degradation of key nutrients, thereby promoting deficiencies as well as toxic interactions with vitamin A and beta carotene. Conversely, nutritional deficits may affect the toxicity of ethanol and acetaldehyde, as illustrated by the depletion in glutathione, ameliorated by S-adenosyl-L-methionine. Other "supernutrients" include polyunsaturated lecithin, shown to correct the alcohol-induced hepatic phosphatidylcholine depletion and to prevent alcoholic cirrhosis in nonhuman primates. Thus, a better understanding of the pathology induced by ethanol is now generating improved prospects for therapy.
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Affiliation(s)
- C S Lieber
- Section of Liver Disease and Nutrition, Bronx VA Medical Center, New York
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Klassen LW, Tuma DJ, Sorrell MF, McDonald TL, DeVasure JM, Thiele GM. Detection of reduced acetaldehyde protein adducts using a unique monoclonal antibody. Alcohol Clin Exp Res 1994; 18:164-71. [PMID: 8198215 DOI: 10.1111/j.1530-0277.1994.tb00898.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Acetaldehyde (AA), the major product of alcohol metabolism, has been shown to bind to proteins in vivo and form chemical adducts. These AA-protein adducts have been shown to alter protein structure and function and may result in tissue damage. Recent reports have shown that polyclonal antibodies can be produced that recognize proteins modified in vitro with AA in the presence of sodium cyanoborohydride (NaCNBH3), a strong reducing (R) agent. Antibodies prepared in this way have been shown to recognize proteins in the livers of rats fed alcohol chronically. Because multiple AA-protein adducts can be recognized by polyclonal antisera, and a variety of adducts may be formed in vitro or in vivo, this study was designed to develop monoclonal antibodies specific for proteins modified by AA. In addition, adducts formed under R conditions are probably chemically different than those formed under nonreducing (NR) conditions, and monoclonal antibodies may provide the specificity required to distinguish these chemical differences. Balb/c mice were immunized with bovine brain tubulin that was modified by treatment with 5 mM AA for 7 days under NR conditions. Sera from immunized animals were tested for antibody activity to the immunogen (protein-NR) and for cross-reactivity to protein-R and unmodified protein. Although the highest serum antibody titers were seen toward the NR adduct, antibodies to the R adduct were also detected. This activity difference was independent of the carrier protein, because NR and R bovine serum albumin, keyhole limpet hemocyanin, and actin also gave similar results when used as the adducted protein.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L W Klassen
- Alcohol Research Center, Omaha Veterans Administration Medical Center, Nebraska
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Abstract
We have recently shown that 34 different Helicobacter pylori strains of human and three of animal origin contain alcohol dehydrogenase (ADH). Isoelectric focusing of the enzyme showed activity bands with pI at 7.1-7.3, a pattern different from that of gastric mucosal ADHs. The Km value of H. pylori ADH for ethanol oxidation ranges from 64 to 104 mM. Although H. pylori ADH was capable of utilizing both NADP and NAD as cofactors in alcohol oxidation, it showed a strong preference for NADP over NAD. At neutral pH H. pylori ADH was more effective in aldehyde reduction than in alcohol oxidation. Distinct findings suggest that H. pylori ADH could be a metabolic enzyme taking part in ethanol production by fermentation. It is a rather abundant enzyme comprising approx. 0.5% of all bacterial cytosolic proteins. Therefore, the enzyme presumably has a basic role in the functions and maintenance of H. pylori. 4-methylpyrazole inhibits H. pylori ADH, and suppresses its growth during culture. Bismuth compounds that are commonly used in the treatment of H. pylori associated gastric diseases appeared to be potent inhibitors of H. pylori ADH. Owing to its high specific activity for ethanol (14 U mg-1) under physiological conditions H. pylori ADH can also effectively produce acetaldehyde at moderate ethanol levels. This reversed function of the enzyme and the production of the toxic and reactive acetaldehyde could account for at least some of the gastrointestinal morbidity associated with H. pylori infection. H. pylori lacks aldehyde dehydrogenase activity and can therefore not remove acetaldehyde at least by this pathway.
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Affiliation(s)
- M Salaspuro
- University of Helsinki, Research Unit of Alcohol Diseases, Finland
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Lieber CS. Mechanisms of ethanol-drug-nutrition interactions. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 1994; 32:631-81. [PMID: 7966525 DOI: 10.3109/15563659409017974] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Mechanisms of the toxicologic manifestations of ethanol abuse are reviewed. Hepatotoxicity of ethanol results from alcohol dehydrogenase-mediated excessive hepatic generation of nicotinamide adenine dinucleotide and acetaldehyde. It is now recognized that acetaldehyde is also produced by an accessory (but inducible) pathway, the microsomal ethanol-oxidizing system, which involves a specific cytochrome P450. It generates oxygen radicals and activates many xenobiotics to toxic metabolites, thereby explaining the increased vulnerability of heavy drinkers to industrial solvents, anesthetics, commonly used drugs, over-the-counter medications and carcinogens. The contribution of gastric alcohol dehydrogenase to the first pass metabolism of ethanol and alcohol-drug interactions is now recognized. Alcohol also alters the degradation of key nutrients, thereby promoting deficiencies as well as toxic interactions with vitamin A and beta-carotene. Conversely, nutritional deficits may affect the toxicity of ethanol and acetaldehyde, as illustrated by the depletion in glutathione, ameliorated by S-adenosyl-L-methionine. Other supernutrients include polyenylphosphatidylcholine, shown to correct the alcohol-induced hepatic phosphatidylcholine depletion and to prevent alcoholic cirrhosis in non-human primates. Thus, a better understanding of the pathology induced by ethanol has now generated improved prospects for therapy.
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Affiliation(s)
- C S Lieber
- Alcohol Research and Treatment Center, VA Medical Center, Bronx, NY 10468
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Lieber CS. Aetiology and pathogenesis of alcoholic liver disease. BAILLIERE'S CLINICAL GASTROENTEROLOGY 1993; 7:581-608. [PMID: 8219401 DOI: 10.1016/0950-3528(93)90003-b] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Until the 1960s, liver disease of the alcoholic patient was attributed exclusively to dietary deficiencies. Since then, however, our understanding of the impact of alcoholism on nutritional status has undergone a progressive evolution. Alcohol, because of its high energy content, was at first perceived to act exclusively as 'empty calories' displacing other nutrients in the diet, and causing primary malnutrition through decreased intake of essential nutrients. With improvement in the overall nutrition of the population, the role of primary malnutrition waned and secondary malnutrition was emphasized as a result of a better understanding of maldigestion and malabsorption caused by chronic alcohol consumption and various diseases associated with chronic alcoholism. At the same time, the concept of the direct toxicity of alcohol came to the forefront as an explanation for the widespread cellular injury. Some of the hepatotoxicity was found to result from the metabolic disturbances associated with the oxidation of ethanol via the liver alcohol dehydrogenase (ADH) pathway and the redox changes produced by the generated NADH, which in turn affects the metabolism of lipids, carbohydrates, proteins and purines. Exaggeration of the redox change by the relative hypoxia which prevails physiologically in the perivenular zone contributes to the exacerbation of the ethanol-induced lesions in zone 3. In addition to ADH, ethanol can be oxidized by liver microsomes: studies over the last twenty years have culminated in the molecular elucidation of the ethanol-inducible cytochrome P450IIE1 (CYP2E1) which contributes not only to ethanol metabolism and tolerance, but also to the selective hepatic perivenular toxicity of various xenobiotics. Their activation by CYP2E1 now provides an understanding for the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, 'over the counter' analgesics, chemical carcinogens and even nutritional factors such as vitamin A. Ethanol causes not only vitamin A depletion but it also enhances its hepatotoxicity. Furthermore, induction of the microsomal pathway contributes to increased acetaldehyde generation, with formation of protein adducts, resulting in antibody production, enzyme inactivation and decreased DNA repair; it is also associated with a striking impairment of the capacity of the liver to utilize oxygen. Moreover, acetaldehyde promotes glutathione depletion, free-radical mediated toxicity and lipid peroxidation. In addition, acetaldehyde affects hepatic collagen synthesis: both in vivo and in vitro (in cultured myofibroblasts and lipocytes), ethanol and its metabolite acetaldehyde were found to increase collagen accumulation and mRNA levels for collagen. This new understanding of the pathogenesis of alcoholic liver disease may eventually improve therapy with drugs and nutrients.
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Salmela KS, Roine RP, Koivisto T, Höök-Nikanne J, Kosunen TU, Salaspuro M. Characteristics of Helicobacter pylori alcohol dehydrogenase. Gastroenterology 1993; 105:325-30. [PMID: 7687573 DOI: 10.1016/0016-5085(93)90704-g] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Helicobacter pylori shows alcohol dehydrogenase activity, which in the presence of ethanol leads to in vitro production of acetaldehyde, a toxic and highly reactive substance. The present study was undertaken to further define H. pylori-related ethanol and acetaldehyde metabolism by characterizing H. pylori alcohol dehydrogenase and by determining whether the organism possesses aldehyde dehydrogenase. METHODS Cytosolic alcohol and aldehyde dehydrogenase activities were determined spectrophotometrically. Acetaldehyde produced by cytosol during incubation with ethanol was measured by head space gas chromatography. Isoenzyme pattern was studied using isoelectric focusing. RESULTS Significant alcohol dehydrogenase activity was observed at a neutral pH known to occur in gastric mucus. The Km for ethanol oxidation was approximately 100 mmol/L for the two strains tested. Acetaldehyde was formed already from a low ethanol concentration known to prevail in the stomach endogenously. Isoelectric focusing of the enzyme showed activity bands with pI at 7.1-7.3, a pattern different from that of gastric mucosal alcohol dehydrogenase. 4-methylpyrazole inhibited enzyme activity in a competitive manner and suppressed the growth of the organism during culture. Neither Helicobacter strain studied showed aldehyde dehydrogenase activity and can thus not remove acetaldehyde by that pathway. CONCLUSIONS Acetaldehyde production by H. pylori from exogenous or endogenous ethanol may be a pathogenetic mechanism behind mucosal injury associated with the organism.
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Affiliation(s)
- K S Salmela
- Research Unit of Alcohol Diseases, University of Helsinki, Finland
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Barrio E, Cutrín C, Meniño MJ, Pérez-Becerra E. Comparative effect of nifedipine and S-adenosylmethionine, singly and in combination on experimental rat liver cirrhosis. Life Sci 1993; 52:PL217-20. [PMID: 8483386 DOI: 10.1016/0024-3205(93)90050-d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An experimental rat liver cirrhosis, by means of carbon tetrachloride and ethanol during 8 weeks, was employed to assay the effect of Nifedipine (a calcium antagonist blocker), S-Adenosylmethionine (a precursor of glutathione); singly and in combination on rat liver cirrhosis. A slight decrease of cirrhosis (N.S.) was observed with the pharmacological therapy employed singly. The combination therapy (Nifedipine+S-Adenosylmethionine) significantly inhibited liver cirrhosis (p < 0.01).
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Affiliation(s)
- E Barrio
- Department of Medicine, Faculty of Medicine, University of Santiago de Compostela, Galicia, Spain
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