Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method has been developed for simultaneous analysis of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isoenzymes in small (2.5 mg) liver biopsy cores by starch gel electrophoresis. All the currently recognized hepatic isoenzymes coded by ADH1, ADH2, ADH3 and ADH4 can be detected as can the five ALDH isoenzymes. Using this technique we have investigated the isoenzyme composition of liver samples from English and Chinese subjects and a group of chronic alcoholics. Pronounced racial differences in frequency of ADH2 and ALDH phenotypes were found--only 2 (4%) of English controls had the "atypical" ADH2 variant whereas this was present in 42 (84%) of Chinese subjects, and whereas all the English subjects had the rapidly migrating mitochondrial isoenzyme of ALDH, this was absent in 27 (54%) of Chinese. No differences in ADH or ALDH phenotype were seen in the chronic alcoholics, all of whom were of English origin, compared with the English controls, but there was a reduction in overall ALDH activity and particularly in the mitochondrial isoenzyme in those with cirrhosis. The reduction in ALDH activity is probably acquired; by limiting acetaldehyde oxidation it could be responsible for the rapid deterioration in liver function in patients who continue drinking excessively.
 ...
PMID:Hepatic ADH and ALDH isoenzymes in different racial groups and in chronic alcoholism. 635 65

In western industrialized countries ethanol is an important etiologic factor in the development of cirrhosis of the liver. Metabolic, immunologic and physico-chemical alterations of the hepatocyte due to ethanol are involved in the pathogenesis of alcoholic liver disease. However, the mechanisms by which ethanol damages the liver are far from clear. During the last two decades, the effect of ethanol on multiple biochemical pathways of the hepatocyte has been investigated intensively. The present paper is focusing on the metabolic aspects of alcoholic liver disease. In the first part of the review, special emphasis has been led on the metabolites of ethanol oxidation, while in the second part microsomal enzyme induction due to alcohol has been discussed. More than 90% of ethanol metabolism takes place in the liver via cytoplasmic alcoholdehydrogenase (ADH) and via a microsomal ethanol oxidizing system (MEOS). The products of these reactions are reduced nicotinadenine dinucleotide phosphate (NADH), acetaldehyde and acetate. NADH alters the redox state of the liver cell favouring all reductive processes. This shift in metabolic pathways results in hyperlactacidaemia, lactacidosis, ketosis and hyperuricaemia. Disturbances of the carbohydrate metabolism may lead either to hypo- or hyperglycaemia. The altered redox state also influences the metabolic pathways of lipid metabolism leading to lipid accumulation within the hepatocyte which can be morphologically observed as alcoholic fatty liver. In addition, porphyrin and collagen metabolism is also affected by the increased NADH/NAD+ ratio. On the other hand, acetaldehyde damages the microtubular system and the mitochondria. Acetaldehyde may also be responsible for the increased lipidperoxidation after chronic ethanol ingestion.
 ...
PMID:[Metabolic aspects of alcoholic liver damage: 1984/5 update. 1. Epidemiology and alcohol metabolism]. 639 85

The mechanisms responsible for the increased hepatic collagen deposition in alcoholic cirrhosis remain unknown. The question of whether ethanol or acetaldehyde has a direct effect on collagen and noncollagen protein production was investigated in human fibroblasts with no detectable activity of alcohol dehydrogenase to distinguish the effects of these metabolites. To eliminate environmental factors, protein production by confluent human skin, fetal and hepatic fibroblasts was studied after three passages. Cells were labeled with [5-3H]proline for 4 hr in the presence of 0.2 mM ascorbate alone or with addition of either ethanol (50 mM) or acetaldehyde (0 to 300 microM). Rates of protein production were calculated from the radioactivities of collagenase-sensitive and collagenase-resistant proteins. Skin fibroblasts from alcoholic individual either with cirrhosis or without liver disease have comparable rates of collagen and noncollagen protein production. Acetaldehyde, in a concentration found in the liver during ethanol abuse, significantly increased collagen production by human skin fibroblasts (up to 140%), fetal fibroblasts (up to 240%) and hepatic fibroblasts (up to 70%) but the addition of ethanol had no significant effect on basal collagen production. The effect of acetaldehyde was dose-related and affected noncollagen protein production in a similar manner. Acetaldehyde did not cause changes in either proline transport or the specific activity of the proline precursor pool. This newly recognized stimulation of collagen production by acetaldehyde may be a possible mechanism of fibrogenesis in alcoholic individuals.
 ...
PMID:Acetaldehyde stimulates collagen and noncollagen protein production by human fibroblasts. 647 53

Acetaldehyde in non-toxic doses (15.6 micrograms per start) causes in the inhibition test of the migration of leucocytes an inhibition of the migration in 6/13 of the patients with alcoholic hepatitis, a stimulation of the migration in 6/11 of alcohol cirrhoses. Healthy (n = 16) persons, patients with alcoholic fatty degeneration of the liver (n = 3) as well as non-alcoholic liver diseases (chronic persisting hepatitis, n = 11; chronic active hepatitis, n = 8, cirrhosis, n = 7) did not show this cellular immune reagibility. The inhibition of the migration and the stimulation of the migration, respectively, might develop by hapten autoantigen complexes (altered cytoskeleton?) with release of the factors of inhibition of migration and stimulation of migration, in which case the role of a hapten belongs to acetaldehyde. The results of the tests did not correlate with functional and histological findings of the liver, with the actual consumption of alcohol and also not with haptoglobin phaenotypes. When it is postulated that by acetaldehyde also the release of further lymphokines is mediated, origin and progression of alcoholic hepatitis and alcoholic cirrhosis might be explained immunopathogenetically.
 ...
PMID:[Acetaldehyde-induced leukocyte migration inhibition in alcoholic liver diseases]. 712 38

Ethanol is easily absorbed from the intestine and diffuses quickly throughout body water. The bulk of ethanol is metabolized in the liver, where alcohol dehydrogenase, a complex mixture of isoenzymes, oxidizes ethanol to acetaldehyde. Ethanol abuse produces functional and structural changes in the gastrointestinal tract, such as in the stomach, small intestine, liver, and pancreas. Accumulating evidence suggests direct toxicity of ethanol and possibly of acetaldehyde. Fatty liver, alcoholic hepatitis, liver cirrhosis, acute and chronic gastritis, deranged structure and function of the small intestine, acute and chronic pancreatitis, and pancreatic lithiasis are some of the sequelae of ethanol abuse. Recent investigations have enhanced our understanding of the functional and structural changes of the gastrointestinal tract produced by the abuse of ethanol.
 ...
PMID:Ethanol, the liver, and the gastrointestinal tract. 719 92

This study was carried out in an attempt to differentiate between the contribution of liver impairment and direct actions of alcohol in myopathy of alcoholic liver disease. Using an animal model of cirrhosis we have previously shown that protein synthetic potential in muscle was not significantly altered. We therefore investigated the possibility that muscle degradation is increased. Cirrhosis was induced by carbon tetrachloride gavage in male rats receiving phenobarbitone in their drinking water. Controls were given phenobarbitone alone. After 135 days the free, latent and total activities of the lysosomal enzymes cathepsin B and cathepsin D in gastrocnemius muscle were unaffected by the induction of experimental cirrhosis when expressed relative to tissue wet weight, protein or DNA. The non-lysosomal enzyme neutral protease was also measured in gastrocnemius muscle from control and cirrhotic rats. There was no difference between the two groups in the free, latent or total activities. Addition of ethanol and acetaldehyde to the assay mixtures in some cases significantly altered the relative activities of the proteases in latent and free compartments of the cirrhotic tissues. In control tissues a different pattern of response emerged. It is concluded that in cirrhosis, at least in the carbon tetrachloride-induced rat model, there is no change of the activity of cathepsin B and D and the neutral protease activity in gastrocnemius. Small but significant effects of ethanol and its metabolite acetaldehyde on latent and free muscle protease activity were demonstrated.
 ...
PMID:Skeletal muscle protease activities are unaltered in cirrhotic rats but altered in response to ethanol and acetaldehyde in vitro. 766 39

Because alcoholic hepatitis and cirrhosis, well-known complications of alcohol abuse, do not occur in all alcoholics, genetic factors such as differences in alcohol-metabolizing enzymes may play a role in the development of alcoholic liver disease. Cytochrome P450IIE1 catalyzes the oxidation of ethanol, producing acetaldehyde and free radicals capable of reacting with and peroxidizing cell membranes. Polymorphisms have been identified in the 5'-flanking region of the P450IIE1 gene that may alter the transcriptional activity of the gene. In this study, we analyzed the P450IIE1 genotypes at the polymorphic PstI and RsaI restriction enzyme sites in 53 Caucasians with severe alcoholic liver disease to determine if there is an association between these polymorphisms and alcoholic liver disease. Subjects that tested positive for the hepatitis C virus were eliminated from the study. To identify the type A (homozygous for the c1 gene), type B (heterozygous for the c1 and c2 genes), and type C (homozygous for the c2 gene) genotypes at the P450IIE1 locus, DNA encompassing the polymorphisms was amplified by polymerase chain reaction, slot-blotted, and probed with allele-specific oligonucleotides. Allele frequencies for the c1 allele were 0.95 for alcoholics with severe liver disease, 0.95 for alcoholics without liver disease, and 0.98 for the general population. No differences in allele frequencies between alcoholic patients with severe liver disease and alcoholics without liver disease were observed.
 ...
PMID:Polymorphism at the P450IIE1 locus is not associated with alcoholic liver disease in Caucasian men. 777 48

Liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for the oxidation of ethanol, are polymorphic at the ADH2, ADH3 and ALDH2 loci in human beings. Our previous studies have shown that, compared with nonalcoholic individuals, Chinese alcoholic patients without liver disease had significantly lower frequencies of the ADH2*2 and ADH3*1 alleles, which encode high maximum velocity beta 2- and gamma 1-ADH subunits, respectively, as well as a lower frequency of the ALDH2*2 allele, which encodes an enzymatically inactive subunit. The data strongly suggest that genetic variation in both ADH and ALDH may influence drinking behavior and the risk of alcoholism developing through acetaldehyde formation. To further investigate the possible role of acetaldehyde in the pathogenesis of alcoholic liver disease, we determined the ADH and ALDH genotype frequencies in patients with alcohol-related cirrhosis (n = 27), viral hepatitis-related cirrhosis (n = 29) and gastric and duodenal ulcer without relevance to alcohol (n = 30). We developed a new restriction fragment length polymorphism method to genotype the mutant and normal ALDH2 alleles by using polymerase chain reaction-directed mutagenesis, which proved to be simpler and faster than the conventional detection methods that use hybridization with allele-specific oligonucleotide probes. We found that the frequencies of the alleles ADH2*2 (57%), ADH3*1 (78%) and ALDH2*2 (9%) in the alcoholic cirrhotic patients were significantly lower than those in the healthy controls and in the patients with cirrhosis from viral hepatitis and with gastric and duodenal ulcer.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Polymorphism of alcohol and aldehyde dehydrogenase genes and alcoholic cirrhosis in Chinese patients. 790 79

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)
 ...
PMID:Collagen-acetaldehyde adducts in alcoholic and nonalcoholic liver diseases. 791 86

The location of acetaldehyde binding sites in the axial unit cell of tendon collagen was investigated by neutron diffraction. Acetaldehyde forms spontaneous cross-links with specific residues in collagen. The use of deuterated acetaldehyde increased the neutron scattering length of these groups. The introduction of deuterated acetaldehyde at specific locations allowed the acetaldehyde-reacted collagen to be treated as multiple isomorphous derivatives for neutron fibre diffraction. The low resolution axially projected structure was determined using amplitudes of the first eight meridional reflections (d = 67 nm). Results indicate that the process of acetaldehyde labelling takes place at different rates at different sites within the collagen fibril. The position of acetaldehyde attachment correlates well with the position of lysine and hydroxylysine residues especially in the regions of the molecular termini. This information is relevant to the process of cirrhosis and fibrosis of the liver since adduction of collagen by acetaldehyde may interfere with normal Schiff base cross-link formation at the C- and N-termini. This may result in subsequent alterations in the intra- and inter-molecular cross-linking pattern of collagen molecules.
 ...
PMID:The in vitro binding of acetaldehyde to collagen studied by neutron diffraction. 798 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>