Ethanol Metabolism and Pathophysiology of Alcoholic Liver Disease

1985 ◽  
pp. 19-47 ◽  
Author(s):  
C. S. Lieber
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Ethanol Metabolism

scholarly journals Investigating RNA expression profiles altered by nicotinamide mononucleotide therapy in a chronic model of alcoholic liver disease

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammed A. Assiri ◽  
Hadi R. Ali ◽  
John O. Marentette ◽  
Youngho Yun ◽  
Juan Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Mapk Pathway ◽  
Early Stage ◽  
Expression Profiles ◽  
Ethanol Metabolism ◽  
Metabolic Dysregulation ◽  
Nicotinamide Mononucleotide ◽  
The Impact

Abstract Background Chronic alcohol consumption is a significant cause of liver disease worldwide. Several biochemical mechanisms have been linked to the initiation and progression of alcoholic liver disease (ALD) such as oxidative stress, inflammation, and metabolic dysregulation, including the disruption of NAD+/NADH. Indeed, an ethanol-mediated reduction in hepatic NAD+ levels is thought to be one factor underlying ethanol-induced steatosis, oxidative stress, steatohepatitis, insulin resistance, and inhibition of gluconeogenesis. Therefore, we applied a NAD+ boosting supplement to investigate alterations in the pathogenesis of early-stage ALD. Methods To examine the impact of NAD+ therapy on the early stages of ALD, we utilized nicotinamide mononucleotide (NMN) at 500 mg/kg intraperitoneal injection every other day, for the duration of a Lieber-DeCarli 6-week chronic ethanol model in mice. Numerous strategies were employed to characterize the effect of NMN therapy, including the integration of RNA-seq, immunoblotting, and metabolomics analysis. Results Our findings reveal that NMN therapy increased hepatic NAD+ levels, prevented an ethanol-induced increase in plasma ALT and AST, and changed the expression of 25% of the genes that were modulated by ethanol metabolism. These genes were associated with a number of pathways including the MAPK pathway. Interestingly, our analysis revealed that NMN treatment normalized Erk1/2 signaling and prevented an induction of Atf3 overexpression. Conclusions These findings reveal previously unreported mechanisms by which NMN supplementation alters hepatic gene expression and protein pathways to impact ethanol hepatotoxicity in an early-stage murine model of ALD. Overall, our data suggest further research is needed to fully characterize treatment paradigms and biochemical implications of NAD+-based interventions.

Effect of liver disorders on ethanol elimination and alcohol and aldehyde dehydrogenase activities in liver and erythrocytes

1989 ◽  
Vol 76 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Antonio Zorzano ◽  
Luis Ruiz del Arbol ◽  
Emilio Herrera
Keyword(s):  
Liver Disease ◽  
Aldehyde Dehydrogenase ◽  
Alcoholic Liver Disease ◽  
Ethanol Metabolism ◽  
Control Group ◽  
Aldh Activity ◽  
Healthy Control ◽  
Ethanol Elimination ◽  
Kinetics Of ◽  
Adh Activity

1. Liver biopsies were performed in healthy control subjects and in subjects with alcoholic and non-alcoholic liver disease in order to examine alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase [ALDH; aldehyde dehydrogenase (NAD+); EC 1. 2. 1. 3] activities. Erythrocyte ALDH and ethanol metabolism were also investigated in the same subjects. 2. Fifteen per cent of the subjects studied (seven of 48 subjects tested) presented atypical ADH activity, characterized by elevated activity at pH 7.4 or 8.8 compared with that found in subjects with the usual ADH form. However, the ethanol elimination curves obtained in two subjects with atypical ADH were indistinguishable from the kinetics of the group with normal ADH. Subjects displaying atypical ADH activity showed normal liver and erythrocyte ALDH activities. 3. Considering only the subjects with the normal ADH form, hepatic ADH activity was unaltered in subjects with non-alcoholic liver disease (chronic hepatitis or cirrhosis) and in those with alcoholic steatosis. Subjects with alcoholic hepatitis or alcoholic cirrhosis showed a lower ADH activity compared with the healthy control group. 4. In spite of the changes detected in subjects with alcoholic liver disease, curves of blood ethanol concentration after oral administration of 0.4 g of ethanol/kg were indistinguishable between the alcoholic hepatitis group and the control group. 5. Hepatic ALDH activity, assayed at 300 μmol/l acetaldehyde, was found to be diminished in all liver pathologies investigated, regardless of their aetiology. Nevertheless, erythrocyte ALDH activity was not modified in subjects with non-alcoholic or alcoholic liver disease. As a result of these findings, no relationship was found between hepatic and erythrocyte ALDH. 6. In summary, our data demonstrate that (a) marked modifications in ADH activity, as found in patients with atypical ADH or in subjects with alcoholic liver disease, are not accompanied by parallel alterations in the kinetics of ethanol disappearance, suggesting that ADH activity per se does not limit ethanol metabolism in vivo, (b) hepatic high-Km ALDH activity is decreased in patients with liver disease independent of alcoholism, and therefore decreased ALDH activity cannot be considered as a primary defect in alcoholism but as a consequence of liver damage, and (c) erythrocyte ALDH does not reflect hepatic high-Km ALDH.

scholarly journals Cytochrome P450S and Alcoholic Liver Disease

2018 ◽  
Vol 24 (14) ◽  
pp. 1502-1517 ◽  
Author(s):  
Yongke Lu ◽  
Arthur I. Cederbaum
Keyword(s):  
Cytochrome P450 ◽  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Cytochrome P450s ◽  
Ethanol Metabolism ◽  
Alcohol Metabolism ◽  
Cytochrome P450 Enzymes ◽  
Major Focus ◽  
Relationship Of ◽  
The Relationship

Alcohol consumption causes liver diseases, designated as Alcoholic Liver Disease (ALD). Because alcohol is detoxified by alcohol dehydrogenase (ADH), a major ethanol metabolism system, the development of ALD was initially believed to be due to malnutrition caused by alcohol metabolism in liver. The discovery of the microsomal ethanol oxidizing system (MEOS) changed this dogma. Cytochrome P450 enzymes (CYP) constitute the major components of MEOS. Cytochrome P450 2E1 (CYP2E1) in MEOS is one of the major ROS generators in liver and is considered to be contributive to ALD. Our labs have been studying the relationship between CYP2E1 and ALD for many years. Recently, we found that human CYP2A6 and its mouse analog CYP2A5 are also induced by alcohol. In mice, the alcohol induction of CYP2A5 is CYP2E1-dependent. Unlike CYP2E1, CYP2A5 protects against the development of ALD. The relationship of CYP2E1, CYP2A5, and ALD is a major focus of this review.

scholarly journals Alcohol-induced microtubule acetylation leads to the accumulation of large, immobile lipid droplets

2019 ◽  
Vol 317 (4) ◽  
pp. G373-G386 ◽  
Author(s):  
Jennifer L. Groebner ◽  
Marlene T. Girón-Bravo ◽  
Mia L. Rothberg ◽  
Raghabendra Adhikari ◽  
Dean J. Tuma ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Lipid Droplet ◽  
Alcoholic Liver Disease ◽  
Protein Trafficking ◽  
Early Stage ◽  
Western Diet ◽  
Ethanol Metabolism ◽  
Droplet Dynamics ◽  
Almost All

Although steatosis (fatty liver) is a clinically well-described early stage of alcoholic liver disease, surprisingly little is known about how it promotes hepatotoxicity. We have shown that ethanol consumption leads to microtubule hyperacetylation that can explain ethanol-induced defects in protein trafficking. Because almost all steps of the lipid droplet life cycle are microtubule dependent and because microtubule acetylation promotes adipogenesis, we examined droplet dynamics in ethanol-treated cells. In WIF-B cells treated with ethanol and/or oleic acid (a fatty acid associated with the “Western” diet), we found that ethanol dramatically increased lipid droplet numbers and led to the formation of large, peripherally located droplets. Enhanced droplet formation required alcohol dehydrogenase-mediated ethanol metabolism, and peripheral droplet distributions required intact microtubules. We also determined that ethanol-induced microtubule acetylation led to impaired droplet degradation. Live-cell imaging revealed that droplet motility was microtubule dependent and that droplets were virtually stationary in ethanol-treated cells. To determine more directly whether microtubule hyperacetylation could explain impaired droplet motility, we overexpressed the tubulin-specific acetyltransferase αTAT1 to promote microtubule acetylation in the absence of alcohol. Droplet motility was impaired in αTAT1-expressing cells but to a lesser extent than in ethanol-treated cells. However, in both cases, the large immotile droplets (but not small motile ones) colocalized with dynein and dynactin (but not kinesin), implying that altered droplet-motor microtubule interactions may explain altered dynamics. These studies further suggest that modulating cellular acetylation is a potential strategy for treating alcoholic liver disease. NEW & NOTEWORTHY Chronic alcohol consumption with the “Western diet” enhances the development of fatty liver and leads to impaired droplet motility, which may have serious deletrious effects on hepatocyte function.

scholarly journals Peroxisome Proliferator-Activated Receptor and Retinoic X Receptor in Alcoholic Liver Disease

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Tommaso Mello ◽  
Simone Polvani ◽  
Andrea Galli
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Molecular Mechanisms ◽  
Redox Balance ◽  
Ethanol Metabolism ◽  
Peroxisome Proliferator ◽  
Clinical Progression ◽  
Metabolizing Enzymes ◽  
Peroxisome Proliferator Activated Receptor ◽  
Reciprocal Interactions

A growing number of new studies demonstrate that nuclear receptors are involved in the development of alcoholic liver disease (ALD). Ethanol metabolism and RXR/PPAR functions are tightly interconnected in the liver. Several ethanol metabolizing enzymes are potently regulated by RXR and PPARαafter alcohol consumption. The increased ethanol metabolism, in turn, leads to alteration of the redox balance of the cells and impairment of RXR/PPAR functions by direct and indirect effects of acetaldehyde, resulting in deranged lipid metabolism, oxidative stress, and release of proinflammatory cytokines. The use of animal models played a crucial role in understanding the molecular mechanisms of ALD. In this paper we summarize the reciprocal interactions between ethanol metabolism and RXR/PPAR functions. In conclusion, RXR and PPAR play a central role in the onset and perpetuation of the mechanisms underling all steps of the clinical progression in ALD.

Crystalloid Inclusions in Hepatocyte Mitochondria and Their Similarity to Cytoplasmic Crystalloids

1974 ◽  
Vol 32 ◽  
pp. 198-199
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Special Interest ◽  
Structural Variations ◽  
Mitochondrial Alterations ◽  
The Matrix ◽  
Crystalloid Inclusions ◽  
Liver Biopsies

Mitochondrial alterations were studied in 25 liver biopsies from patients with alcoholic liver disease. Of special interest were the morphologic resemblance of certain fine structural variations in mitochondria and crystalloid inclusions. Four types of alterations within mitochondria were found that seemed to relate to cytoplasmic crystalloids.Type 1 alteration consisted of localized groups of cristae, usually oriented in the long direction of the organelle (Fig. 1A). In this plane they appeared serrated at the periphery with blind endings in the matrix. Other sections revealed a system of equally-spaced diagonal lines lengthwise in the mitochondrion with cristae protruding from both ends (Fig. 1B). Profiles of this inclusion were not unlike tangential cuts of a crystalloid structure frequently seen in enlarged mitochondria described below.

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