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Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using indirect immunofluorescence technique, 21 cases of hepatic cirrhosis of differing etiology were studied with type-specific antibodies to collagen type I, II, and III. In all cases the fibrous septa and portal tracts showed an increase in type III collagen. No fluorescence could be observed with antibodies to collagen type I and II. Thus, biochemical studies are supported which show, in addition to type III collagen, a new, as yet undescribed type of collagen in liver cirrhosis that is similar to type I collagen electronmicroscopically, but differs from type I collagen biochemically and immunologically. No correlation between the etiology of cirrhosis and the pattern of different collagen types could be found. The origin of different collagen types in liver cirrhosis is briefly discussed.
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PMID:[Immunohistochemical characterization of collagen in liver cirrhosis (author's transl)]. 80 1

Collagen in bulk was isolated in about 30% yield from the livers of normal human beings and from livers of persons with alcholic cirrhosis. Analyzed chemically and examined by electron microscopy, the collagen in each case was shown to consist of two types identical with, or resembling closely, type I and type III collagens of skin. The collagen from normal liver was predominantly type I, whereas, that from cirrhotic livers consisted or approximately equal amounts of the two types. By chromatography on carboxymethyl-cellulose, the type I collagen from the cirrhotic livers showed one alpha2chain and two alpha1 chains. The alpha1 chains were separable from one another, but gel electrophoretic patterns of peptides obtained from them after treatment with CNBr were almost identical, and resembled the pattern obtained with CNBr peptides of the alpha1 chain of rat skin type I collagen. The increased collagen of both types was responsible in part for the observed distortion of the architecture of the cirrhotic livers associated with increased rigidity of the stroma. The predominance of type III collagen in the areas of collapse of architecture where, as shown by others, few fibroblasts are present, suggests that hepatocytes might have an important function in fibrogenesis during the course of liver cirrhosis.
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PMID:Increase in type I and type III collagens in human alcoholic liver cirrhosis. 106 Nov 56

We recently found that polyunsaturated lecithin prevents ethanol from causing cirrhosis in the baboon. Because transformation of lipocytes to transitional cells plays a key role in hepatic fibrogenesis in vivo, and because this process in alcohol-fed baboons was found to be attenuated by polyunsaturated lecithin, we focused on lipocytes to study the mechanism of the protective effect. Rat lipocytes cultured on plastic undergo spontaneous activation, accompanied by expression of alpha-smooth muscle actin isoform and production of substantial amounts of type I collagen. The latter was further increased on incubation with acetaldehyde. This in vitro model was used here to study how acetaldehyde-mediated collagen production and accumulation can be turned off. Addition of polyunsaturated lecithin (10 mumols/L) was found to prevent the acetaldehyde-induced increase in collagen accumulation by 83% (p less than 0.001). By contrast, a saturated phospholipid (10 mumols/L dilauroyl phosphatidylcholine), a monounsaturated one (10 mumols/L linoleoyl-palmitoyl phosphatidylcholine) or linoleic acid (20 mumols/L bound to albumin) had no such effect. Incorporation of [3H]proline into collagen and the expression of alpha-1 (I) procollagen mRNA were increased by acetaldehyde; the latter was not significantly affected by polyunsaturated lecithin. Polyunsaturated lecithin increased lipocyte collagenase activity by 100% (p less than 0.001), whereas dilauroyl phosphatidylcholine, linoleoyl-palmitoyl phosphatidylcholine and linoleic acid had no such action. We concluded that (a) polyunsaturated lecithin selectively prevents the acetaldehyde-induced increase in collagen accumulation in lipocyte cultures, whereas other phospholipids or linoleate have no such effect; and (b) polyunsaturated lecithin does not modify the acetaldehyde-mediated increase in alpha-1 (I) procollagen mRNA, but it increases collagenase activity, suggesting that the protective effect exerted by polyunsaturated lecithin against alcohol induced fibrosis in vivo is due at least in part to stimulation of collagenase activity, which may prevent excess collagen accumulation by offsetting increased collagen production.
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PMID:Polyunsaturated lecithin prevents acetaldehyde-mediated hepatic collagen accumulation by stimulating collagenase activity in cultured lipocytes. 137 80

We have investigated the effects of nontoxic doses of vitamin A on the hepatic contents of collagen and sulfated glycosaminoglycans (SGAGs) in rats chronically treated with CCl4. When the animals were treated with this retinoid before the intoxication with CCl4, liver collagen level was significantly reduced as compared with that in rats that received only CCl4 (3.31 +/- 0.40 vs 5.00 +/- 0.61 mg/gm wet liver, mean +/- SD, respectively), although no significant differences were found for the relative proportion of type III collagen related to type I collagen. The absolute increment in the total amount of liver SGAG in the vitamin A--pretreated group was followed by a more important increase in the concentration of dermatan sulfate as compared with the CCl4 group (dermatan sulfate-to-heparan sulfate ratio: 1.15 for the CCl4 group vs 1.70 for the vitamin A--pretreated group). A significant proportion of the dermatan sulfate from this last group was of higher molecular weight when compared with the dermatan sulfate found in the liver of rats that received only CCl4. Our results indicate that the pretreatment with vitamin A modifies hepatic collagen and SGAG deposition and can inhibit or delay the development of liver cirrhosis in rats chronically treated with CCl4. We speculate that this effect could be due to the changes in the fat-storing (Ito) cells phenotype induced by vitamin A.
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PMID:Effects of vitamin A administration on collagen and sulfated glycosaminoglycans contents in the livers of rats treated with carbon tetrachloride. 159 6

This radioimmunoassay for type I collagen mainly detects degradation products of the molecule in human serum samples. Type I collagen antigenicity in serum can be separated into two peaks by gel-filtration chromatography. The larger form represents collagen molecules (as shown by immunoblotting experiments), and (or) type I collagen with aminoterminal propeptide or intact procollagen molecules. The smaller form, the exact nature of which is not known, is quantitatively the principal antigenic form and is derived from degradation of type I collagen. The concentration of type I collagen in serum is increased mainly in cirrhotic patients, with or without active liver disease, but also somewhat in alcoholic patients without cirrhosis.
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PMID:Radioimmunoassay of type I collagen that mainly detects degradation products in serum: application to patients with liver diseases. 231 Dec 7

Hepatic production of type I collagen is markedly increased in liver cirrhosis. Previous studies using primary liver cell cultures have demonstrated that hepatocytes, lipocytes and endothelial cells are all capable of producing collagen. In this study in situ hybridization and hepatic cell sorting have been used to identify which cells are expressing the type I collagen gene, alpha 1(I), in normal rat liver. Northern blotting of mRNAs from purified hepatic cell populations demonstrated that both hepatocytes and several types of non-parenchymal cells express the collagen alpha 1(I) gene. Calculations based on cell numbers, yields of mRNA, and cellular mRNA concentration demonstrated that the majority of collagen alpha 1(I) mRNA originates from the hepatocytes in the normal liver. Localization of a collagen alpha 1(I) mRNA by in situ hybridization confirmed that both hepatocytes and non-parenchymal cells express this gene. Furthermore, collagen alpha 1(I) gene expression in hepatocytes was obtained by transfecting a reporter gene driven by the collagen alpha (I) 5' regulatory segment in primary liver cell cultures. Future experiments will further characterize the regulation of collagen alpha 1(I) gene expression in the liver.
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PMID:Expression of collagen genes in the liver. 234 27

Three collagen types (I, III and IV) and fibronectin were localized in normal and alcoholic human liver by light and electron microscopy using the indirect immunoperoxidase technique. In normal liver, most of the bundles of collagen fibers stained for type pro-III collagen while only a few reacted for type I. Basement membranes stained for type IV collagen which formed discontinuous discrete deposits in sinusoids. Only fibronectin appeared as an almost continuous layer in the space of Disse. At the intracellular level, hepatocytes were found to contain little type I collagen and large amounts of fibronectin. Fat-storing cells strongly stained for type IV collagen and expressed low amounts of types I and III collagen and fibronectin. Endothelial cells contained low amounts of all the components. Alcoholic livers were studied at three stages: steatosis, fibrosis and cirrhosis. Qualitative and quantitative differences were observed in extracellular and intracellular distributions of matrix proteins. Increased amounts of all components were usually found in fibrotic and cirrhotic livers compared to normal liver. In two fibrotic livers which contained numerous bundles of collagen in the sinusoids, fat-storing cells stained more intensely for type III collagen. In a cryptogenic fibrotic liver, abundant type IV collagen was observed in hepatocytes. These results suggest that hepatocytes, fat-storing cells and endothelial cells are engaged in production of extracellular matrix components in normal human liver. In fibrosis, hepatocytes which normally did not synthesize types III and IV collagen may produce these collagens.
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PMID:Cell types involved in collagen and fibronectin production in normal and fibrotic human liver. 351 7

Monospecific antibodies against collagen types I, IV, fibronectin, and laminin were used to characterize the hepatic extracellular matrix in CCl4-induced cirrhosis. Of the four antigens studied, fibronectin was the first (2 weeks) to be deposited in Disse's space. Synthesis of fibronectin by hepatocytes was demonstrable by 3 weeks. This increased synthesis and deposition of fibronectin continued throughout the cirrhotic process. Type I collagen was deposited in the same areas as fibronectin, but there was a delay of 2 weeks between fibronectin deposition and the subsequent type I collagen deposition. Like fibronectin, type I collagen was localized in the rough endoplasmic reticulum of hepatocytes, but unlike fibronectin type I collagen synthesis was restricted to hepatocytes near zones of necrosis. Type I collagen and fibronectin synthesis were demonstrable only in hepatocytes. Type IV collagen deposition was noticeable after 3 to 4 weeks of CCl4 administration and continued throughout the cirrhotic process. Laminin deposition was delayed, with regard to type IV collagen, by 1 to 2 weeks. Except for this time lag, both basement membrane components codistributed in the space of Disse and were synthesized by the same cells: endothelial, smooth muscle, and Ito cells. The deposition of these two basement membrane components culminated with the formation of continuous endothelial basement membranes. The four extracellular matrix components studied were synthesized and secreted by resident cells of the normal liver. It is proposed that fibronectin deposition in the space of Disse, modulating collagen deposition, may be the crucial event in the cirrhotic process. The interposition of basement membranes between plasma and hepatocytes may have profound effects on hepatic systemic functions.
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PMID:The hepatic extracellular matrix. II. Electron immunohistochemical studies in rats with CCl4-induced cirrhosis. 389 94

The distribution of collagen types I, III, and V in normal and fibrotic human livers and hepatocellular carcinoma was studied by indirect immunofluorescence procedure using type specific antibodies. Type I collagen as well as type III collagen was present in normal liver within the portal tracts and along the perisinusoidal spaces. Basement membrane collagen, type V collagen, was demonstrated only around the bile ducts and vessels of the portal tracts and central veins. In fibrotic liver, both type I and III collagens were found in increased amounts in fibrotic areas. In fibrous septa of active cirrhosis, however, type I collagen as well as type III collagen was abundant, whereas in inactive cirrhosis type I fibers were predominant. Type V collagen was observed in the walls of proliferative bile ductules and vessels in the fibrotic liver, and also along the sinusoids in the periportal areas. In hepatocellular carcinoma, each type of collagen was distributed regularly along the sinusoid-like vascular channels within the tumor.
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PMID:Distribution of collagen types I, III, and V in fibrotic and neoplastic human liver. 632 63

Examination of 51 human liver specimens with the modified Kupffer's gold impregnation method confirmed the presence and distribution of fat-storing cells in various kinds of diseased livers such as fatty liver, acute centrolobular necrosis, subacute massive necrosis and cirrhosis as well as in liver cell carcinoma. In normal liver, gold-reactive fat-storing cells were distributed in the central area or diffusely in lobules. In the liver with marked fatty change and obstructive jaundice, presence of fat-storing cells was able to be clarified by this method. In cases of acute hepatocellular necrosis, the necrotic areas contained a large number of fat-storing cells in contrast to adjacent areas. In cases of subacute massive hepatic necrosis and cirrhosis, the areas with abundant newly formed collagen fibers (type III collagen) contained many gold-reactive fat-storing cells. In the septa consisting of dense type I collagen fibers, by contraries, fat-storing cells were hardly visible. The features suggested that fat-storing cells are closely related to intralobular fibrogenesis. In one case of liver cell carcinoma, there were many gold-reactive fat-storing cells in tumour tissue.
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PMID:Pathological study on gold impregnation of fat-storing cells in human liver. 723 21


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