Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0239946 (liver fibrosis)
 8,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monospecific antibodies directed against type I, type III collagens, and prolyl hydroxylase were used to clarify the process of liver fibrosis after CCl4 intoxication in rats by the direct immunoperoxidase method. In acute CCl4 intoxication, fat-storing cells (FSCs) were increased in number in the areas of necrosis around the central veins. These FSCs exhibited intense positive stainings for type I, type III collagens, and prolyl hydroxylase in well-developed rough endoplasmic reticula and Golgi apparatus. This was the direct evidence that the collagens formed after CCl4 intoxication are produced by FSCs. In chronic CCl4 intoxication, increased FSCs in and around the fibers also contained strong immunoreactive materials of both collagens and prolyl hydroxylase mainly in the rough endoplasmic reticula. These collagens were also present in the Golgi apparatus and vesicles close to the cytoplasmic membrane, demonstrating the exocytic process of collagen formation of FSCs. In contrast, faint immunoreactions of both collagens were found in the rough endoplasmic reticula and Golgi apparatus of hepatocytes during the process of fibrosis. These findings indicate that FSCs play an important role in fibrogenesis after acute and chronic CCl4 intoxication in the rat.
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PMID:Collagen production in fat-storing cells after carbon tetrachloride intoxication in the rat. Immunoelectron microscopic observation of type I, type III collagens, and prolyl hydroxylase. 284 91

Dimethylnitrosamine-induced liver damage, which leads to hepatic failure and death of the animal, was prevented by treatment with malotilate. The accumulation of collagen and the morphologic changes caused by dimethylnitrosamine, such as inflammatory cell accumulation and fibrosis, were also prevented by this drug. Malotilate drastically reduced the increases in the amount of type I procollagen alpha 2-chain mRNA and activities of the enzymes prolyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase, which are early events in liver fibrosis preceding the deposition of collagen. Even when started 14 days after dimethylnitrosamine induction, malotilate treatment was able to reduce liver damage. We suggest that the effect of malotilate is a result of the inhibition of inflammation.
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PMID:Preventive effect of malotilate on dimethylnitrosamine-induced liver fibrosis in the rat. 291 82

The dynamics of hepatic collagen biosynthesis and degradation were studied in mice infected with Schistosoma japonicum. Hepatic fibrosis, the major clinical manifestation of disease, increased during acute infection (0-15 wk). The majority of proline incorporation into hydroxyproline, which was reflective of collagen synthesis, was found within hepatic egg granulomas. As the disease became chronic (20-30 wk) there was a decrease in collagen synthesis and a maintenance of total collagenolytic activity, which resulted in decreased accumulations of both total hepatic and granuloma-associated collagen. In addition to these quantitative decreases in extracellular collagen there was a qualitative change in the type of hepatic collagen synthesized. Early in infection, type I collagen was the predominant biosynthetic product, whereas late in infection type III collagen became the dominant isotype. A similar switch was seen in the substrate specificity of the constitutive collagenolytic activity, with decreasing type I activity and increasing type III activity as the disease progressed from acute (10 wk) to chronic (30 wk). These changes in the quantity and makeup of extracellular collagen may lead to amelioration of disease and potential reversibility of fibrosis.
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PMID:Dynamics of collagen accumulation and polymorphism in murine Schistosoma japonicum. 299 Oct 69

Schistosomiasis mansoni is characterized by granulomatous inflammations, deposition of collagen, and irreversible liver fibrosis. In chronic infections fibrosis is cumulative, while collagen synthesis and degradation are diminished. In the present study, we compared collagenase, elastase, and nonspecific neutral protease (NP) activities in isolated vigorous (8-week infection) and immunomodulated (18-20-week infection) liver granulomas. Enzyme activity was localized in the adherent macrophage (greater than 90% purity) and nonadherent eosinophil-rich (greater than 70% purity) cell fractions of the disaggregated granulomas. Collagenase levels were approximately two times higher in granuloma extracts and explant culture supernates of the vigorous as compared with the immunoregulated lesions. However, macrophages and eosinophil-rich cells derived from either type of granuloma secreted similar enzyme levels. Elastase and NP levels in granuloma extracts and secretions of adherent macrophage and eosinophil-rich cell populations were the same in vigorous or immunomodulated lesions but were significantly greater in vigorous granuloma culture supernates. In addition to active collagenase, trypsin activatable latent collagenase was also present in both types of granuloma extracts, explants and eosinophil-rich cell culture supernates. Latent elastase was also detected in granuloma extracts or explant supernates but was absent from secretions of granuloma cells. These results suggest that the presence of active neutral proteases within granulomas may play an important role in the regulation of tissue repair and remodeling during the fibrotic process.
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PMID:Collagenase, elastase, and nonspecific protease production by vigorous or immunomodulated liver granulomas and granuloma macrophages/eosinophils of S mansoni-infected mice. 299 60

Sake, a rice wine, induced hepatic collagen accumulation in rats. This was noted after 16 weeks of a liquid diet containing 35% ethanol by caloric content. However, under similar experimental conditions, whiskey and ethanol did not produce any changes. Hepatic collagenase activities in sake-fed rats were slightly, but significantly, higher than in the whiskey group. The central and pericellular liver fibrosis in sake-fed rats was caused possibly by either accelerated collagen synthesis or maturation, exceeding the increased collagen degradation. Mechanisms of enhanced fibrogenesis in sake-fed rats were discussed.
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PMID:Accumulation of hepatic collagen following long-term administration of sake to rats. 300 74

To evaluate if serum procollagen type III peptide levels reflect the extent of liver fibrosis and hepatic collagen synthesis, we have studied 19 patients with histologically proven alcoholic hepatitis and 9 chronic alcoholics with normal liver histology or minimal steatosis. Serum procollagen peptide type III was measured at the time of liver biopsy, and determination of hepatic prolyl-hydroxylase activity, as an index of collagen synthesis, was performed in all liver samples. Hepatic prolyl-hydroxylase activity and serum procollagen peptide levels were significantly higher in patients with alcoholic hepatitis (959 +/- 115 cpm/mg and 33.2 +/- 5.3 ng/ml, respectively) than in alcoholics from the control group (537 +/- 62 cpm/mg and 10.9 +/- 1.5 ng/ml, respectively) (p less than 0.05 and p less than 0.01, respectively). All patients with alcoholic hepatitis had fibrosis (10 mild and 9 severe). Prolyl-hydroxylase activity and procollagen peptide levels were significantly higher in alcoholic hepatitis patients with severe fibrosis than in those with mild fibrosis (1208 +/- 154 cpm/mg vs. 734 +/- 138 cpm/mg, p less than 0.05 and 49.1 +/- 8.8 ng/ml vs. 20.4 +/- 2.6 ng/ml, p less than 0.01). Furthermore, a close correlation was found between the hepatic prolyl-hydroxylase activity and the serum level of procollagen peptide (r = 0.76, p less than 0.001). We conclude that the serum procollagen peptide level is a good marker of hepatic fibrogenesis in alcoholic hepatitis; thus, its serial measurement could be useful in identifying patients in progress to cirrhosis and in assessing the therapeutic efficiency of antifibrogenic drugs.
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PMID:Serum procollagen type III peptide as a marker of hepatic fibrogenesis in alcoholic hepatitis. 300 61

Type V collagen-degrading enzyme activity was detected as a metalloprotease acting at neutral pH in the human liver. Type V collagen extracted from human placenta and labeled with [1-14C] acetic anhydride was used as the substrate in the assay. Four major degradation products with relatively high molecular weights were observed upon polyacrylamide gel electrophoresis of the incubation mixture of type V collagen and liver homogenate. The significance of the measurement of this enzyme activity was discussed in relation to the clarification of the mechanism of liver fibrosis.
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PMID:Detection of type V collagen-degrading enzyme activity in human liver. 301 52

The effect of malotilate on liver fibrosis of rat induced by carbon tetrachloride (CCl4) was studied. CCl4 was given subcutaneously (1.5 ml/kg) to male Wistar rats twice a week for 11 weeks. Administration of malotilate (100 mg/kg) 5 times a week was started in the 5th experimental week and continued thereafter. The biochemical parameters in serum such as concentration of total protein and transaminase activities were improved by malotilate administration. The livers treated with CCl4 only were atrophic and markedly nodular, and histologically, severe collagen deposition and pseudolobular formation were observed. However, the livers treated with CCl4 and malotilate showed only slight accumulation of collagen fibers although hypertrophic and fatty metamorphosis was observed. Immunocytochemically, type I and type III collagens were stained in livers from rats treated with CCl4 only and rats treated with CCl4 and malotilate, but stainability was rather weak in the latter. The increased amount of hydroxyproline in the liver and that excreted into urine were markedly suppressed by malotilate administration. The levels of protocollagen prolyl hydroxylase activity in the liver were almost the same in CCl4-treated and CCl4 and malotilate-treated rats. However, the levels of collagenolytic enzyme activity were slightly higher in the latter. From these results, anti-fibrotic action of malotilate was clear and involvement of enhanced collagenolytic enzyme activity was suggested.
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PMID:Anti-fibrotic effect of malotilate on liver fibrosis induced by carbon tetrachloride in rats. 302 33

Liver fibrosis in rats was induced by repeated subcutaneous injections of carbon tetrachloride. Total collagen, soluble and insoluble collagen fractions as well as type I and type III collagen content in the liver were subsequently measured over a 3-18 week period. Liver collagen was found to increase exponentially during this time. Insoluble collagen accumulated more rapidly than soluble forms, and the accumulation of type III collagen was relatively greater than type I collagen. Changes in specific liver enzymes were also observed. Collagenase, collagenolytic cathepsin and collagen peptidase activities all increased. Levels of collagen-degrading enzymes increased rapidly during the first weeks of fibrosis-induction, and were followed by a more gradual increase during the remainder of the study.
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PMID:Dynamics of collagen accumulation and activity of collagen-degrading enzymes in the liver of rats with carbon tetrachloride-induced hepatic fibrosis. 303 9

Primary monolayer cultures of rat hepatocytes at confluence were exposed to an exogenously added source of superoxide, and its influence on collagen synthesis was examined. Superoxide was generated by the addition of dihydroxyfumarate to the culture medium. Exposure of hepatocytes to dihydroxyfumarate greatly stimulated the activity of prolyl hydroxylase and the synthesis of collagen. A significant increase in prolyl hydroxylase activity was observed with 5 micrograms per ml dihydroxyfumarate in 24 hr relative to that in the untreated cultures. Maximum stimulation of greater than 3-fold compared to the control value was elicited by 25 micrograms per ml dihydroxyfumarate. When scavengers of superoxide such as superoxide dismutase and Cu(Lys)2 were added in the medium, the increase in prolyl hydroxylase activity induced by dihydroxyfumarate was nearly abolished. Experiments with actinomycin D indicated that synthesis of new RNA was involved in the stimulation of prolyl hydroxylase activity. Analysis of collagen synthesis in cultures exposed to dihydroxyfumarate also showed a marked increase compared to that of the untreated cultures. The presence of superoxide dismutase in the medium significantly reduced the increase in collagen synthesis. Our results indicate that superoxide mediates the stimulation of collagen synthesis in hepatocytes. These findings may provide a possible explanation for excess collagen formation during induced liver fibrosis.
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PMID:Increased prolyl hydroxylase activity and collagen synthesis in hepatocyte cultures exposed to superoxide. 303 59


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