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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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152
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Mendenhall CL, Roselle GA, Grossman CJ, Gartside P. II: the effects of recombinant human insulin-like growth factor-1 on immunological recovery in the malnourished alcoholic rat. Alcohol Clin Exp Res 1997; 21:1682-9. [PMID: 9438530 DOI: 10.1111/j.1530-0277.1997.tb04507.x] [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: 02/05/2023]
Abstract
BACKGROUND/AIMS Immunological abnormalities are frequently observed in alcoholics with severe liver disease and are typically in association with immune abnormalities. Concomitantly, serum levels of insulin-like growth factor-1 (IGF-1) are frequently very low in these patients. Because IGF-1 is known to modulate both nutrition and immune status, the present study was undertaken to evaluate an in vivo rat model of alcoholism and malnutrition, the possibility of a therapeutic application for IGF-1. METHODS Controlled injury was induced by 14 days of calorie restriction and alcohol feeding that resulted in a 9% loss of body mass. Changes were compared with normal unrestricted control rats that gained 28% above their pretreatment body mass during the same period. Immunological impairment was assessed using thymus and spleen mass, cellularity and spleen T-lymphocyte function. Recovery was evaluated after 28 days of treatment using various combinations of: (1) high calorie intake, (2) cessation from alcohol feeding, and (3) IGF-1. RESULTS The thymus was most severely affected, losing 52.3% of its mass and 55.7% of its cellularity. The spleen was diminished, losing 31.2% of its mass and 41.9% of its cellularity. All of the spleen T-lymphocyte subsets were diminished, with CD5 affected the least (37.1 %) and CD8 affected the most severely (51.7%). During recovery, only the group treated with high calorie intake, no alcohol intake, and IGF-1 (group 8) had complete restoration of all immunological parameters, including a recovery of T-lymphocyte function. Continuous consumption of alcohol, even in the presence of high calories and IGF-1, produced an incomplete recovery. CONCLUSIONS Cessation of alcohol coupled with high calorie nutrition and IGF-1 treatment produced an accelerated improvement in host immunity. These animal studies suggest that IGF-1 is efficacious for this condition and supports the need for additional clinical studies.
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Affiliation(s)
- C L Mendenhall
- Department of Veterans Affairs Medical Center, and Department of Medicine, University of Cincinnati Medical Center, Ohio 45220, USA
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153
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Laso FJ, Lapena P, Madruga JI, San Miguel JF, Orfao A, Iglesias MC, Alvarez-Mon M. Alterations in Tumor Necrosis Factor-alpha, Interferon-gamma, and Interleukin-6 Production by Natural Killer Cell-Enriched Peripheral Blood Mononuclear Cells in Chronic Alcoholism: Relationship with Liver Disease and Ethanol Intake. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb04442.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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154
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Eastin CE, McClain CJ, Lee EY, Bagby GJ, Chawla RK. Choline Deficiency Augments and Antibody to Tumor Necrosis Factor-alpha Attenuates endotoxin-Induced Hepatic Injury. Alcohol Clin Exp Res 1997. [DOI: 10.1111/j.1530-0277.1997.tb04250.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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155
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Pennington HL, Hall PM, Wilce PA, Worrall S. Ethanol feeding enhances inflammatory cytokine expression in lipopolysaccharide-induced hepatitis. J Gastroenterol Hepatol 1997; 12:305-13. [PMID: 9195371 DOI: 10.1111/j.1440-1746.1997.tb00426.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Elevated concentrations of plasma tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 and IL-6 have been detected in patients with alcoholic hepatitis and have been implicated in the pathogenesis of hepatocyte necrosis. The present study used a rat model to conduct a detailed histological and biochemical examination of the expression of various pro-inflammatory cytokines and associated liver pathology in ethanol-potentiated lipopolysaccharide (LPS)-induced liver injury. Male Wistar rats were pair-fed either the control or ethanol-containing (36% of caloric intake as ethanol) form of the Lieber-DeCarli liquid diet for 6 weeks. Liver injury was induced by the i.v. injection of LPS (1 microgram/g bodyweight), with animals being killed at 0, 1, 3, 6, 12 and 24 h after injection. At the later time points, plasma transaminase and transpeptidase activities were significantly elevated in ethanol-fed LPS-treated rats compared with control-fed LPS-treated animals. At these times after LPS treatment, hepatocytes in ethanol-fed animals displayed fatty change and necrosis with an associated neutrophil polymorph infiltrate. Time course analysis revealed that plasma TNF-alpha (1-3 h post-LPS) and IL-6 (3 h post-LPS) bioactivity was significantly elevated in ethanol-fed compared with control-fed animals. No difference was seen in plasma IL-1 alpha concentration (maximal in both groups 6 h post-LPS). The expression of TNF-alpha, IL-1 alpha, IL-1 beta and IL-6 mRNA were elevated between 1 and 6 h post-LPS in the livers of both control and ethanol-fed rats. However, ethanol-fed LPS-treated animals exhibited significantly higher maximal expression of IL-1 and IL-6 mRNA. Comparison of the appearance of cytokine mRNA and plasma bioactivity indicated an effect of ethanol feeding on post-transcriptional processing and/or the kinetics of the circulating cytokines. Elevated levels of both hepatic cytokine mRNA expression and the preceding plasma cytokines are presumably a necessary prerequisite for hepatic injury seen in this model and, therefore, possibly for the damage seen in human alcoholics. Further studies using this model may lead to significant advances in our understanding of the pathogenic mechanisms of alcoholic liver disease in humans.
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Affiliation(s)
- H L Pennington
- Department of Biochemistry, University of Queensland, Australia
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156
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Yang SQ, Lin HZ, Lane MD, Clemens M, Diehl AM. Obesity increases sensitivity to endotoxin liver injury: implications for the pathogenesis of steatohepatitis. Proc Natl Acad Sci U S A 1997; 94:2557-62. [PMID: 9122234 PMCID: PMC20127 DOI: 10.1073/pnas.94.6.2557] [Citation(s) in RCA: 615] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Genetically obese fatty/fatty rats and obese/obese mice exhibit increased sensitivity to endotoxin hepatotoxicity, quickly developing steatohepatitis after exposure to low doses of lipopolysaccharide (LPS). Among obese animals, females are more sensitive to endotoxin liver injury than males. LPS induction of tumor necrosis factor alpha (TNF alpha), the proven affecter of endotoxin liver injury, is no greater in the livers, white adipose tissues, or sera of obese animals than in those of lean controls. Indeed, the lowest serum concentrations of TNF occur in female obese rodents, which exhibit the most endotoxin-induced liver injury. Several cytokines that modulate the biological activity of TNF are regulated abnormally in the livers of obese animals. After exposure to LPS, mRNA of interferon gamma, which sensitizes hepatocytes to TNF toxicity, is overexpressed, and mRNA levels of interleukin 10, a TNF inhibitor, are decreased. The phagocytic activity of liver macrophages and the hepatic expression of a gene encoding a macrophage-specific receptor are also decreased in obesity. This new animal model of obesity-associated liver disease demonstrates that hepatic macrophage dysfunction occurs in obesity and suggests that this might promote steatohepatitis by sensitizing hepatocytes to endotoxin.
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Affiliation(s)
- S Q Yang
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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157
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Laso FJ, Madruga JI, López A, Ciudad J, Alvarez-Mon M, San Miguel J, Orfao A. Distribution of peripheral blood lymphoid subsets in alcoholic liver cirrhosis: influence of ethanol intake. Alcohol Clin Exp Res 1996; 20:1564-8. [PMID: 8986204 DOI: 10.1111/j.1530-0277.1996.tb01700.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of the present study was to investigate the effect of chronic ethanol (EtOH) consumption on the immune system in patients with alcoholic liver cirrhosis (ALC), as analyzed by the distribution of peripheral blood (PB-) T, B, and NK lymphoid subsets using multiple stainings with monoclonal antibodies and flow cytometry. For that purpose, we have analyzed a group of patients with ALC and active EtOH intake (ALCET group) which were re-evaluated 3 months after alcohol withdrawal. As controls, both ALC patients with at least 1 year of alcohol withdrawal (ALCAW group) and healthy subjects were used. Regarding the alcohol intake period, the most relevant findings were a significant activation of the PB T-cell compartment, and specifically of the TCR alpha beta + subset, as reflected by an increased expression of both the HLA DR and CD11c antigens as well as a significant increase of both the PB NK cells (CD3-/CD56+) and the cytotoxic T cells coexpressing the CD3 and CD56 molecules. In addition, a decrease of both the numbers of total B cells and their CD5+/CD19+ subset were observed. After a relatively short withdrawal period (3 months), the abnormalities of T, P, and NK cells disappeared. These findings suggest the existence of a close relationship between EtOH consumption and the abnormalities of the immune system observed during active alcoholism. Nevertheless, ALCAW individuals displayed marked alterations on the immunophenotypic profile, as reflected by a significantly decreased number of total T cells, due to reduced levels of the CD3+/TCR alpha beta+, CD4+, CD8+, and CD4+/CD45RA+ T-cell subsets. In addition, a significantly decreased number of total PB B cells was observed in this group of patients. Our results show that in patients suffering from ALC, the abnormalities of the immune system due to a direct effect of EtOH intake (or its metabolites) should be distinguished from the immunological alterations related to the liver disease itself.
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Affiliation(s)
- F J Laso
- Servicio de Medicina Interna II, Hospital Universitario, Salamanca, Spain
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158
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Cressman DE, Greenbaum LE, DeAngelis RA, Ciliberto G, Furth EE, Poli V, Taub R. Liver failure and defective hepatocyte regeneration in interleukin-6-deficient mice. Science 1996; 274:1379-83. [PMID: 8910279 DOI: 10.1126/science.274.5291.1379] [Citation(s) in RCA: 1179] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Liver regeneration stimulated by a loss of liver mass leads to hepatocyte and nonparenchymal cell proliferation and rapid restoration of liver parenchyma. Mice with targeted disruption of the interleukin-6 (IL-6) gene had impaired liver regeneration characterized by liver necrosis and failure. There was a blunted DNA synthetic response in hepatocytes of these mice but not in nonparenchymal liver cells. Furthermore, there were discrete G1 phase (prereplicative stage in the cell cycle) abnormalities including absence of STAT3 (signal transducer and activator of transcription protein 3) activation and depressed AP-1, Myc, and cyclin D1 expression. Treatment of IL-6-deficient mice with a single preoperative dose of IL-6 returned STAT3 binding, gene expression, and hepatocyte proliferation to near normal and prevented liver damage, establishing that IL-6 is a critical component of the regenerative response.
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Affiliation(s)
- D E Cressman
- Department of Genetics and Medicine, University of Pennsylvania School of Medicine, 705a Stellar-Chance, 422 Curie Boulevard, Philadelphia, PA 19104-6145, USA
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159
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Sponsel HT, Guzelian PS, Brown SE, Breckon R, Ray C, Simon FR, Anderson RJ. Mechanisms of recovery from mechanical injury of cultured rat hepatocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:C721-7. [PMID: 8843700 DOI: 10.1152/ajpcell.1996.271.3.c721] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The mechanism(s) whereby hepatocytes restore denuded areas remains unknown. We therefore studied the recovery of denuded areas made in monolayers of primary cultures of rat hepatocytes. Minimal recovery occurred in cells plated on plastic. Plating on Matrigel produced modest recovery (25% at 24 h), whereas plating on a type I collagen substrate resulted in > 70% recovery at 24 h. The rate of recovery on collagen could be attenuated by a monoclonal antibody directed against the extracellular domain of the beta 1-integrin subunit. Monoclonal antibodies directed against CD44 (the hyaluron receptor) and E-cadherin did not influence the rate of recovery. Recovery could be stimulated, in a dose-dependent fashion, by epidermal and hepatocyte growth factors. The effects of epidermal and hepatocyte growth factors to promote recovery occurred in the absence of 5-bromo-2'-deoxyuridine uptake, suggesting a proliferation-independent mechanism. Transforming growth factor-beta 1 inhibited recovery. Exposure to selected cytokines (interleukins 1 and 2), an adenine nucleotide [adenosine 5'-O-(3-thiotriphosphate)], adenosine, pertussis toxin, and selected agents that bind to fibronectin and other matrix component adhesive sites (heparin and the RGD peptide) did not influence the rate of recovery of hepatocytes. However, the peptide DGEA, which can bind to collagen adhesive sites, attenuated recovery. These studies demonstrate that primary cultures of rat hepatocytes require a particular type of extracellular matrix to renew denuded areas and that the beta 1-integrin subunit may be involved in this recovery process. Hepatocyte recovery of denuded areas can be modulated by growth factors in both a stimulatory (epidermal and hepatocyte growth factors) and an inhibitory (transforming growth factor-beta 1) fashion.
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Affiliation(s)
- H T Sponsel
- Denver Veterans Affairs Medical Center, Colorado, USA
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160
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161
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162
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Deaciuc IV, Alappat JM, McDonough KH, D'Souza NB. Interleukin-6 tumor necrosis factor-alpha clearance and metabolism in vivo and by the isolated, perfused liver in the rat: effect of acute alcohol administration. Alcohol Clin Exp Res 1996; 20:293-301. [PMID: 8730220 DOI: 10.1111/j.1530-0277.1996.tb01642.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Plasma clearance and organ distribution of intravenously injected human recombinant [125I]interleukin (IL)-6 and [125I]tumor necrosis factor (TNF)-alpha were studied in male rats, 2 hr after intravenous alcohol (ethanol) administration (single dose, 2.2 g.kg-1 body weight). Also, the rate of uptake and degradation of the two cytokines by the isolated, perfused rat liver was studied in the absence or in the presence of ethanol (35 mM) in the perfusate. Acute ethanol administration significantly increased plasma clearance rate for both cytokines (36% and 72%, for IL-6 and TNF-alpha, respectively), decreased the t1/2 alpha (30% and 11%, for IL-6 and TNF-alpha, respectively), abolished the slow (beta)-phase component for TNF-alpha, and increased t1/2 beta for IL-6 (31%). Although alcohol did not affect organ distribution of TNF-alpha, it increased the IL-6 content in the liver, kidney, and blood. IL-6 uptake rate by the isolated, perfused rat liver was 2-fold higher than TNF-alpha uptake, whereas the rate of degradation was larger for TNF-alpha than for IL-6, despite the fact that both cytokines were presented to the liver at the same concentration (6 nM). Ethanol addition to the perfusate (35 mM, final concentration) significantly increased TNF-alpha uptake (24%), without affecting IL-6 uptake or the degradation rate of either cytokine. Also, the kinetics of degradation by the isolated, perfused rat liver was linear for TNF-alpha, but exponential for IL-6. Data presented in this study demonstrate that: (1) acute alcohol consumption can alter the kinetic behavior of IL-6 and TNF-alpha in the bloodstream, mainly by accelerating their clearance which, in turn, may counteract the outcome of cytokine secretion and delivery to the blood; and (2) short exposure of liver to ethanol levels commonly seen in humans after binge drinking may alter its capacity to take up cytokines.
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Affiliation(s)
- I V Deaciuc
- Department of Physiology, Louisiana State University Medical Center, New Orleans 70112-1393, USA
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163
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Huang YS, Chan CY, Wu JC, Pai CH, Chao Y, Lee SD. Serum levels of interleukin-8 in alcoholic liver disease: relationship with disease stage, biochemical parameters and survival. J Hepatol 1996; 24:377-84. [PMID: 8738722 DOI: 10.1016/s0168-8278(96)80156-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND/AIMS Interleukin-8 (IL-8), a cytokine produced by a host of cells, including monocytes, macrophages, Kupffer cells and hepatocytes, can activate neutrophils. Peripheral neutrophilia and liver neutrophil infiltration are frequently noted in patients with alcoholic liver disease. However, the relationship between IL-8 and different stages of alcoholic liver disease is uncertain. The aim of this study is to determine if a correlation exists between circulating IL-8 levels and biochemical and histological parameters and survival in alcoholic liver disease. METHODS Serum levels of IL-8 were determined with an enzyme-linked immunosorbent assay in 166 subjects, consisting of 30 healthy controls, 26 patients with non-alcoholic fatty liver, 15 with alcoholic fatty liver, 32 with alcoholic hepatitis, 30 with alcoholic cirrhosis, 28 with chronic hepatitis B and 5 with chronic hepatitis C. RESULTS Serum IL-8 levels were markedly elevated in patients with alcoholic hepatitis (437 +/- 51 pg/ml) when compared with all other groups (p < 0.05). Levels of IL-8 in patients with alcoholic fatty liver, alcoholic cirrhosis and viral hepatitis were higher than those in controls and in patients with non-alcoholic fatty liver. In addition, IL-8 levels were higher in patients who died (p = 0.007), and correlated with biochemical and histological parameters, and severity of liver injury: serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, prothrombin time, indocyanine green retention ratio, tumor necrosis factor-alpha and peripheral neutrophil count in patients with alcoholic hepatitis. After a 2-year follow up, patients with IL-8 above 479 pg/ml had a higher mortality rate in the alcoholic hepatitis group (p = 0.033). CONCLUSIONS These findings suggest that IL-8 is activated in alcoholic liver disease, especially in alcoholic hepatitis, and is closely correlated with liver injury. IL-8 levels can reflect the stage and severity of alcoholic liver disease, and may serve as a predictor of survival in patients with alcoholic hepatitis.
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Affiliation(s)
- Y S Huang
- Department of Medicine, Veterans General Hospital-Taipei, Taiwan, R.O.C
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164
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Nanji AA, Tahan SR, Khwaja S, Yacoub LK, Sadrzadeh SM. Elevated plasma levels of hyaluronic acid indicate endothelial cell dysfunction in the initial stages of alcoholic liver disease in the rat. J Hepatol 1996; 24:368-74. [PMID: 8778206 DOI: 10.1016/s0168-8278(96)80018-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND/AIMS We used the intragastric feeding rat model for alcoholic liver disease to evaluate the relationship between morphologic and functional indicators of endothelial cell dysfunction. METHODS Twelve groups of rats (4-5 rats/group) were fed the following diets: saturated fat and dextrose (SD), saturated fat and ethanol (SE), corn oil and dextrose (CD), corn oil and ethanol (CE). Four of the 12 groups were sacrificed at 2 weeks, four groups at 4 weeks and remaining four groups at 8 weeks. The following were evaluated at sacrifice: pathologic changes in the liver, endothelial cell proliferation using a monoclonal antibody to proliferating cell nuclear antigen, factor VIII-related antigen staining of endothelial cells in liver, plasma endotoxin, hyaluronan and prostaglandin F2 alpha. RESULTS Only CE rats at 4 and 8 weeks showed pathologic changes. The plasma levels of HA were significantly higher in the CE groups compared to the other groups at all time intervals studied. In the CE rats, a significant correlation was obtained between plasma endotoxin and hyaluronan (r = 0.84, p < 0.01). Endotoxin levels also correlated significantly with the number of G1/S arrested hepatic sinusoidal endothelial cell (r = 0.61, p < 0.05). A role for prostaglandin F2 alpha, in causing endothelial dysfunction, was suggested by a significant correlation between plasma hyaluronan and prostaglandin F2 alpha levels (r = 0.95, p < 0.01). Positive factor VIII related antigen staining of hepatic endothelial cells was seen in rats with high plasma hyaluronan levels. CONCLUSION We propose that endotoxin, mediating part of its effect through prostaglandin F2 alpha, plays a role in hepatic sinusoidal endothelial cell G1/S arrest. This morphologic change, associated with increased plasma hyaluronan levels, precedes capillarization in this model of alcoholic liver injury.
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Affiliation(s)
- A A Nanji
- Department of Pathology, New England Deaconess Hospital, Boston MA 02215, USA
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165
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Affiliation(s)
- C S Lieber
- Alcohol Research and Treatment Center, Veterans Affairs Medical Center, Bronx, NY 10468, USA
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166
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Yacoub LK, Fogt F, Griniuviene B, Nanji AA. Apoptosis and bcl-2 protein expression in experimental alcoholic liver disease in the rat. Alcohol Clin Exp Res 1995; 19:854-9. [PMID: 7485830 DOI: 10.1111/j.1530-0277.1995.tb00958.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We used the intragastric feeding rat model to investigate the relationship between severity of alcoholic liver injury, apoptosis, bcl-2 protein expression, and lipid peroxidation. Rats were fed ethanol with different dietary fats (saturated fat, corn oil, and fish oil) for a 1-month period. Apoptosis was evaluated using an immunohistochemical method, and flow cytometry. Bcl-2 protein concentrations in liver were evaluated by Western blot analysis and lipid peroxidation by measurement of conjugated dienes. Pathological changes (fatty liver, necrosis, and inflammation) were present in corn oil-ethanol and fish oil-ethanol groups only. The highest number of apoptotic cells were seen in the group of rats exhibiting liver injury. The fish oil-ethanol-fed group had the highest concentrations of bcl-2 protein; this protein was localized in the bile duct epithelial and inflammatory cells. A significant correlation was seen between bcl-2 protein assessed densitometrically and the number of inflammatory cells/mm2 (r = 0.78, p < 0.02) and conjugated diene levels (r = 0.82, p < 0.01). Increased numbers of apoptotic cells were seen in rats developing ethanol-induced pathological liver injury. Increased bcl-2 protein concentration are associated with the presence of inflammatory cells and lipid peroxidation.
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Affiliation(s)
- L K Yacoub
- Department of Pathology, New England Deaconess Hospital, Harvard Medical School, Boston, MA 02215, USA
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167
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González-Quintela A, Vidal C, Gude F, Tomé S, Lojo S, Lorenzo MJ, Becerra EP, Martínez-Vazquez JM, Barrio E. Increased serum IgE in alcohol abusers. Clin Exp Allergy 1995; 25:756-64. [PMID: 7584688 DOI: 10.1111/j.1365-2222.1995.tb00014.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND It has been reported that total serum IgE is increased in patients with alcoholic cirrhosis, but it is not clear if this fact is related to alcoholic liver disease or to alcohol intake. OBJECTIVE To measure serum IgE in a group of chronic alcoholics with different stages of liver injury in order to elucidate if IgE increase in related to alcoholic liver damage. PATIENTS AND METHODS Total serum IgE was determined by enzyme immunoassay in 186 chronic alcoholic patients (137 male/49 female) and 101 healthy controls. Patients and controls with known reasons for IgE elevation were excluded. Among alcoholic patients, 24 had fatty liver, 28 hepatic fibrosis, 29 alcoholic hepatitis, and 67 liver cirrhosis (38 patients were not evaluable concerning liver injury). RESULTS Total serum IgE was found to be increased in alcoholics (median 154.5 IU/mL, range 1-7329 IU/mL) with respect to healthy controls (median 20 IU/mL, range < 1-1417 IU/mL) (P < 0.001). IgE increase was moderate (180-1000 IU/mL) in 60 alcoholics (32.3%) and marked ( > 1000 IU/mL) in 27 (14.5%). Male alcoholics had higher IgE levels than females (median 191 IU/mL and range 1-7329 IU/mL vs 105 IU/mL and range 2-2189 IU/mL) ( P = 0.009). On logistic regression analysis, alcoholism, male sex and younger age (but not smoking) were independently associated with higher IgE levels. No clear relationship was noted between serum IgE and severity of alcoholic liver disease. Thus, no correlation was observed between IgE and parameters of liver function (serum bilirubin, albumin or prothrombin index). Likewise, IgE concentrations were not significantly different in patients with liver cirrhosis with respect to patients with less severe liver disease. Serum IgE was increased ( > 180 IU/mL) in 47.8% of cirrhotics and in 44% of patients without liver cirrhosis. In contrast, other immunoglobulins (IgG, IgA and IgM) were significantly correlated with liver dysfunction. CONCLUSION Chronic alcoholism should be considered as a cause of increased total serum IgE, regardless of the severity of the underlying liver disease.
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Affiliation(s)
- A González-Quintela
- Division of Internal Medicine, Complejo Hospitalario Universitario de Santiago, Spain
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168
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Affiliation(s)
- W E Lands
- Division of Basic Research, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland 20892-7003, USA
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169
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Effect of type of dietary fat and ethanol on antioxidant enzyme mRNA induction in rat liver. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)40059-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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170
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Deaciuc IV, D'Souza NB, Spitzer JJ. Tumor necrosis factor-alpha cell-surface receptors of liver parenchymal and nonparenchymal cells during acute and chronic alcohol administration to rats. Alcohol Clin Exp Res 1995; 19:332-8. [PMID: 7625565 DOI: 10.1111/j.1530-0277.1995.tb01511.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) has been shown to contribute to the alcohol [ethanol (ETOH)]-induced alteration of hepatic function. Therefore we tested the hypothesis that the hepatic action of TNF-alpha could be due, at least in part, to alterations in TNF-alpha cell-surface receptors of hepatic parenchymal (hepatocytes) and nonparenchymal (Kupffer and sinusoidal endothelial) cells. Rats were either acutely treated with ETOH by a primed, continuous 7-hr intravenous infusion of 20% (w/v) ETOH (30 mg/100 g body weight/h) or chronically fed an ETOH-containing liquid diet (5.2% ETOH, w/v, with ETOH as 36% of total calories) for 14 weeks. Control rats in the acute group were infused with sterile saline, whereas control rats in the chronic group were fed liquid diet containing dextrin to replace ETOH in isocaloric amounts. Three hr before killing, the rats were injected intravenously with Gram-negative bacterial lipopolysaccharide [(LPS) 100 micrograms/100 g body weight] or saline. Hepatocytes, Kupffer cells, and sinusoidal endothelial cells were isolated after liver perfusion with collagenase (without pronase), separated by centrifugal elutriation, and used to determine the affinity (Kd) and capacity (Bmax) of binding sites, using recombinant human-[125I]TNF-alpha as the ligand. Two binding sites were detected on Kupffer cells and sinusoidal endothelial cells isolated from control animals: a high-affinity (Kd1, in the range of 150-200 pM), low-capacity (Bmax, in the range of 2-3 fmol/10(6) cells) binding site and a low-affinity (Kd2, in the range of 2-9 nM), high-capacity (Bmax2, in the range of 3-15 fmol/10(6) cells) binding site.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- I V Deaciuc
- Department of Physiology, Louisiana State University Medical Center, New Orleans 70112-1393, USA
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171
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Sarphie TG, Deaciuc IV, Spitzer JJ, D'Souza NB. Liver sinusoid during chronic alcohol consumption in the rat: an electron microscopic study. Alcohol Clin Exp Res 1995; 19:291-8. [PMID: 7625560 DOI: 10.1111/j.1530-0277.1995.tb01505.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Transmission and scanning electron microscopic studies were performed on the liver sinusoid, with emphasis on sinusoidal endothelial cells, in rats fed a liquid diet containing either alcohol or dextrin (control) for 14 weeks. Animals were also treated with either Gram-negative bacterial lipopolysaccharide (LPS; 100 micrograms/100 g body weight, intravenously) or sterile saline (control). All specimens were prepared after perfusion fixation of the liver. Livers of rats fed dextrin-containing liquid diet displayed the ultrastructural features typical of the sinusoid and its endothelial cells. Livers from alcohol-fed animals, however, were characterized by massive loss of sieve-plate architecture of the sinusoidal endothelium, which was virtually replaced with a meshwork of enlarged openings with diameters frequently exceeding 1 micron. Morphological evidence of Kupffer cell activation could also be seen along with significant fatty infiltration of the hepatocyte. Conversely, LPS administration to dextrin-fed animals induced an apparent decrease in fenestration of the sinusoidal endothelial cell, accompanied by morphological evidence of enhanced endocytotic activity and cytoplasmic swelling. The changes seen 3 hr after LPS administration were markedly advanced at 24 hr. LPS administration to alcohol-fed rats accentuated the alterations observed after alcohol treatment alone. Additionally, the presence of platelets in the sinusoid as well as adhering to the hepatocyte microvilli in the space of Disse, along with the presence of Ito and Kupffer cell activation, greater than that observed in the alcohol-treated rats, is morphological evidence consistent with the disruption of vascular integrity in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T G Sarphie
- Department of Anatomy, Louisiana State University Medical Center, New Orleans 70112-1393, USA
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172
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Wang JF, Greenberg SS, Spitzer JJ. Chronic alcohol administration stimulates nitric oxide formation in the rat liver with or without pretreatment by lipopolysaccharide. Alcohol Clin Exp Res 1995; 19:387-93. [PMID: 7542848 DOI: 10.1111/j.1530-0277.1995.tb01520.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study examines the effect of chronic alcohol consumption on nitric oxide release from the liver of rats with or without lipopolysaccharide (LPS) (Escherichia coli) treatment. Reactive nitrogen intermediates (RNIs) in plasma were monitored with an NOx Analyzer, and nitric oxide (NO) production was measured as nitrite or nitrite + nitrate accumulation in perfusates of the perfused liver, and in supernatants of the freshly isolated hepatic cells after incubation for 3 hr in Hank's balanced salt solution buffer containing 1 mM L-arginine. RNI concentration in plasma of control rats was 32.0 +/- 3.4 microM (mean +/- SE). Livers from diet-fed control rats produced RNIs at the barely detectable rate of 7.8 +/- 1.5 nmol/hr x g wet liver. Six hr after administration of LPS (1 mg/kg, i.v.), plasma RNI levels in diet-fed control rats increased to 426.9 +/- 29.4 microM, and RNI release from the perfused liver was also markedly elevated to 97.7 +/- 7.7 nmol/hr x wet g liver, indicating hepatic NO release as a potentially important source for the increased RNI in plasma. The presence of NG-monomethyl-L-arginine (0.5-1 mM) or the absence of L-arginine in the perfusate inhibited LPS-induced stimulation of RNI release. EGTA (1 mM) had little effect, indicating that the increased RNI release was likely to be due to inducible NO synthase activity. The release of RNIs by freshly isolated Kupffer cells increased 13-fold, and this small cell mass contributed almost half of the hepatic RNI production under these conditions. Plasma ALT concentration was elevated after LPS administration, indicating incipient liver damage.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J F Wang
- Department of Physiology, Louisiana State University Medical Center, New Orleans, USA
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173
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Abstract
Alcohol exerts potent suppressive effects on the immune system that significantly increase host susceptibility to a variety of infections, particularly pneumonia. Historically, tuberculosis has been strongly associated with alcohol abuse. Although the relationship between alcohol abuse and tuberculosis is widely appreciated, the basic mechanisms by which alcohol immunosuppresses the host remain to be clarified. A major obstacle in furthering our understanding of this association has been the difficulty in distinguishing between the effects of alcohol per se and the other frequent sequelae of alcoholism such as nutritional deficiencies, liver disease, cigarette smoking, hygienic factors, and lifestyle. This article focuses on the role of tumor necrosis factor-alpha (TNF) in host defense and how alcohol modulates the activity of this important cytokine. While TNF's role in mediating the lethal consequences of infection has been the subject of much conjecture, this review focuses on the emerging evidence that TNF is an essential factor in the normal immune response to numerous infections, including tuberculosis.
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Affiliation(s)
- S Nelson
- Department of Pulmonary/Critical Care Medicine, Louisiana State University Medical Center, New Orleans 70112, USA
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174
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Park BK, Pirmohamed M, Kitteringham NR. The role of cytochrome P450 enzymes in hepatic and extrahepatic human drug toxicity. Pharmacol Ther 1995; 68:385-424. [PMID: 8788564 DOI: 10.1016/0163-7258(95)02013-6] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The human cytochrome P450 enzyme system metabolises a wide array of xenobiotics to pharmacologically inactive metabolites, and occasionally, to toxicologically active metabolites. Impairment of cytochrome P450 activity, which may be either genetic or environmental, may lead to toxicity caused by the parent compound itself. In practise, this usually only applies to drugs that have a narrow therapeutic index and when their clearance is critically dependent upon the fraction normally metabolised by that pathway. P450 enzymes may also convert the drug to a chemically reactive metabolite, which, if not detoxified, may lead to various forms of hepatic and extrahepatic toxicity, including cellular necrosis, hypersensitivity, teratogenicity, and carcinogenicity, depending on the site of formation and the relative stability of the metabolite, and the cellular macromolecule with which it reacts. Variation in the regulation and expression of the drug metabolising enzymes may play a key role in both interindividual variation in sensitivity to drug toxicity and tissue-specific damage. Avoidance of toxicity may be possible in rare instances by prediction of individual susceptibility or by designing new chemical entities that are metabolised by a range of enzymes (both cytochromes P450 and others) and do not undergo bioactivation.
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Affiliation(s)
- B K Park
- Department of Pharmacology and Therapeutics, University of Liverpool, UK
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175
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Ott L, McClain CJ, Gillespie M, Young B. Cytokines and metabolic dysfunction after severe head injury. J Neurotrauma 1994; 11:447-72. [PMID: 7861440 DOI: 10.1089/neu.1994.11.447] [Citation(s) in RCA: 179] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Patients with head injury must overcome central as well as peripheral metabolic insults. In addition to specific tissue damage to the brain, a cellular biochemical cascade occurs that can negatively affect organ function, cause a systemic response to injury, and may cause secondary tissue injury. The metabolites involved in this cascade are numerous and complex. Cytokines are important cell-to-cell communication mediators during injury. It is speculated that cytokines, such as interleukin 1 (IL-1), interleukin 6 (IL-6), tumor necrosis factor (TNF), and interleukin 8 (IL-8), which are found in elevated amounts in both human and basic trials after head injury, play a role in the cellular cascade of injury. Some of the metabolic events produced by small doses of cytokine infusion in animals, as well as humans, include fever, neutrophilia, muscle breakdown, altered amino acid metabolism, depression of serum zinc levels, production of hepatic acute phase reactants, increased endothelial permeability, and expression of endothelial adhesion molecules. These are all known sequelae of severe head injury. Cytokines have also been implicated in organ failure. Infusion of cytokines in basic science trials revealed that organ functions of the gut, liver, and lung are negatively altered by high-dose cytokine infusion. Infusion of certain cytokines has been shown to cause death of brain cells, increase blood-brain barrier permeability, and cause cerebral edema. This suggests that cytokines may also play a role in the sequelae of organ demise. These effects of cytokines have been attenuated in basic trials by blocking the initial signaling system of cytokines or by decreasing serum cytokine activity. We hypothesize that cytokines that are elevated after head injury play a role in the pathology of injury, including altered metabolism and organ demise.
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Affiliation(s)
- L Ott
- Department of Surgery, University of Kentucky Medical Center, Lexington
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176
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Nanji AA, Zhao S, Sadrzadeh SM, Dannenberg AJ, Tahan SR, Waxman DJ. Markedly enhanced cytochrome P450 2E1 induction and lipid peroxidation is associated with severe liver injury in fish oil-ethanol-fed rats. Alcohol Clin Exp Res 1994; 18:1280-5. [PMID: 7847620 DOI: 10.1111/j.1530-0277.1994.tb00119.x] [Citation(s) in RCA: 203] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We evaluated the role of changes in cytochrome P-450 2E1 (CYP 2E1) and lipid peroxidation in relation to development of severe liver injury in fish oil-ethanol-fed rats. The experimental animals (male Wistar rats) were divided into 5 rats/group and were fed the following diets for 1 month: corn oil and ethanol (CO+E) or corn oil and dextrose (CO+D), and fish oil and ethanol (FO+E) or fish oil and dextrose (FO+D). For each animal, microsomal analysis of CYP 2E1 protein, aniline hydroxylase activity, fatty acid composition, and conjugated dienes was conducted. Also, evaluation of severity of pathology was done for each rat. The mean +/- SD of the pathology score was significantly higher (p < 0.01) in the FO+E (6.0 +/- 1.3) group than in the CO+E group (3.0 +/- 0.5). No pathological changes were evident in the dextrose-fed controls. The CYP 2E1 protein levels (mean +/- SD) were significantly higher (p < 0.01) in the FO+E group (13.1 +/- 2.0) compared with the CO+E (4.7 +/- 1.2) and FO+D (1.8 +/- 0.5) groups. Higher levels of eicosapentaenoic and docosahexaenoic acids and lower levels of arachidonic acid were detected in liver microsomes from rats fed fish oil compared with corn oil. A significant correlation was obtained between CYP 2E1 protein and conjugated diene levels (r = 0.78, p < 0.01). Our results showing markedly increased CYP 2E1 induction and lipid peroxidation in the FO+E group provides one possible explanation for the greater severity of liver injury in this group.
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Affiliation(s)
- A A Nanji
- Department of Pathology, New England Deaconess Hospital, Boston, MA 02215
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177
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Nanji AA, Tahan SR, Wei Y, Sadrzadeh SM. Hepatic sinusoidal endothelial cell G1/S arrest correlates with severity of alcoholic liver injury in the rat. Gastroenterology 1994; 107:818-23. [PMID: 7915700 DOI: 10.1016/0016-5085(94)90132-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND/AIMS Capillarization of the hepatic sinusoid occurs in alcoholic liver disease. Because endothelial cell proliferation is relevant to capillarization, we used the intragastric feeding rat model to evaluate the relationship between pathological liver injury and endothelial cell proliferation. METHODS Male Wistar rats (225-250 g) were fed liquid diets containing corn oil and ethanol for periods ranging between 1 week and 2 months. At the time the rats were killed, the severity of pathological injury and endothelial cell proliferation using anti-rat proliferating cell nuclear antigen/antibody was evaluated. RESULTS Two distinctly different populations of proliferating sinusoidal lining cells were identified; one population showed relatively weak granular staining consistent with cells arrested at the G1/S boundary. The other population of cells showed strong granular staining of the nucleoplasm and nucleoli (cells in mid to late S phase). A strong correlation (r = 0.85; P < 0.01) was obtained between pathological severity and G1/S-arrested endothelial cells. There was no correlation between cells in S phase. CONCLUSIONS The presence of an increased number of G1/S-arrested endothelial cells in animals with severe pathological change suggests that stimuli are present for both endothelial cell proliferation and G1/arrest. The identification of these stimuli could lead to a better understanding of the pathogenesis of alcoholic liver disease.
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Affiliation(s)
- A A Nanji
- Department of Pathology, New England Deaconess Hospital, Boston, Massachusetts
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178
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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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179
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Mitochondrial Energy Metabolism in Chronic Alcoholism. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/b978-0-12-152517-0.50012-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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180
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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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181
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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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