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C Balabaud

Publications and source records attributed to C Balabaud.

At least 37 records · Page 2Linked to original sources
PubMed1999

Osteonectin/SPARC is overexpressed in human hepatocellular carcinoma.

Osteonectin (ON)/SPARC is a glycoprotein involved in extracellular matrix remodelling. ON expression by myofibroblasts has been reported in fibrotic human liver. As ON also plays a role in cell adhesion, differentiation, and proliferation, this study was designed to document its expression in human hepatocellular carcinoma (HCC). Tissues from 26 HCCs of various histological grades and architecture and from surrounding non-tumour liver (23 cirrhotic or fibrotic, three non-fibrotic) were tested by in situ hybridization and immunohistochemistry. Immunohistochemical detection of alpha-smooth muscle actin (alpha-SMA) was performed on serial sections or in combination with hybridization. Large amounts of ON mRNA and protein were detected in the tumour capsule, in the fibrous bands, and along capillaries within HCCs. The signal was located in cells suggestive of myofibroblasts, as confirmed by positive staining for alpha-SMA. In HCC, ON protein was always detectable, with strong staining in high-grade tumours, whereas it was mostly undetectable in non-tumour tissues. A clear difference was also shown for ON transcripts, except in a few cases with chronic active hepatitis, where ON transcripts were also expressed at a high level. Overexpression of ON transcripts in HCC vs. non-tumour liver was confirmed by RNA blot in 20/22 patients tested. In conclusion, ON is strongly expressed by the stromal myofibroblasts of human HCC, especially of high grade. This expression could play a role in tumour progression.

Actins↗
PubMed1999

Myofibroblasts are responsible for collagen synthesis in the stroma of human hepatocellular carcinoma: an in vivo and in vitro study.

BACKGROUND/AIMS: Marked changes in extracellular matrix occur in the stroma of hepatocellular carcinoma, as compared to normal or cirrhotic liver. The cell types responsible for extracellular matrix synthesis within hepatocellular carcinoma have not been clearly identified. METHODS: In vivo collagen synthesis was studied by in situ hybridization and immunohistochemistry for types I, IV, V and VI collagen, together with immunolabeling of alpha-smooth muscle actin, a myofibroblast marker, and CD34, an endothelial cell marker. In vitro, extracellular matrix deposition by cultured myofibroblasts was studied by reticulin staining, immunocytochemistry and RNase protection. RESULTS: All collagens studied were expressed in the stroma of the tumor, with a higher level of type VI and IV collagens than of type I and V. The majority of the cells expressing collagen transcripts in human hepatocellular carcinoma stroma were alpha-actin positive and CD 34 negative. In vitro experiments demonstrated that the hepatocellular carcinoma cell lines HepG2, HuH7 and Hep3B markedly increased extracellular matrix deposition by human liver myofibroblasts. This increase was mediated by a soluble mediator present in tumor cell conditioned medium. It was not explained by an increase in mRNA levels of extracellular matrix components, nor by a decrease in the secretion of matrix-degrading proteinases by myofibroblasts. CONCLUSIONS: Myofibroblasts are the main source of collagens in the stroma of hepatocellular carcinoma. Our data also indicate that tumoral hepatocytes increase extracellular matrix deposition by cultured myofibroblasts, probably by post-transcriptional mechanisms. The generation of hepatocellular carcinoma stroma by myofibroblasts could thus be under control of tumoral cells.

Carcinoma, Hepatocellular↗
PubMed1999

Premalignant lesions and hepatocellular carcinoma in a non-cirrhotic alcoholic patient with iron overload and normal transferrin saturation.

A 66-year-old white man had a hepatic resection for a 6-cm well-differentiated hepatocellular carcinoma which had developed in a non-cirrhotic liver. The only risk factors found were heavy drinking, smoking and heterozygosity for the C282Y mutation of the HFE gene. The liver was mildly fibrotic and overloaded with iron. It also contained numerous iron-free hepatocellular lesions from <1 to 10 mm, suggesting a premalignant change. These lesions were of three types: (i) iron-free foci, (ii) hyperplastic nodules and (iii) dysplastic nodules with severe dysplasia or even foci of well-differentiated grade I hepatocellular carcinoma. This observation suggests the possibility of malignant transformation of the liver in the newly-described syndrome of iron overload and normal transferrin saturation. It also illustrates the multistep process of carcinogenesis in the non-cirrhotic liver.

Aged↗
PubMed1999

Direct evidence that hepatocyte growth factor-induced invasion of hepatocellular carcinoma cells is mediated by urokinase.

BACKGROUND/AIMS: We have shown that hepatocyte growth factor secreted by human hepatic myofibroblasts increased the in vitro invasion of the hepatocarcinoma cell line HepG2 through Matrigel. Our aim in this study was to evaluate the role of urokinase in this process. METHODS: Expression of urokinase in HepG2 cells was measured by Northern blot and zymography, and plasminogen activation was shown by a chromogenic substrate assay. Cell invasion was assayed on Matrigel-coated filters. Urokinase and urokinase receptor transcripts in hepatocarcinoma were detected by reverse transcription-polymerase chain reaction. Activated hepatocyte growth factor was detected by Western blot with a hepatocyte growth factor-beta chain-specific antibody. RESULTS: HepG2 cells expressed urokinase mRNA and secreted active urokinase. Urokinase expression was enhanced by hepatocyte growth factor at the protein and mRNA level. Notably, cell-surface-associated urokinase was increased 22-fold by hepatocyte growth factor. Hepatocyte growth factor also increased urokinase receptor mRNA expression. B428, a urokinase inhibitor, decreased by up to 70% HepG2 invasion induced by myofibroblasts and by 90% that induced by recombinant hepatocyte growth factor. This was not due to a decrease in the generation of activated hepatocyte growth factor by myofibroblasts. Finally, all 17 hepatocarcinoma samples tested expressed urokinase and urokinase receptor transcripts. CONCLUSION: Hepatocyte growth factor-dependent, myofibroblasts-induced invasion of HepG2 cells is secondary to the induction of urokinase expression on tumor cells.

Carcinoma, Hepatocellular↗
PubMed1999

Activation of cultured rat hepatic stellate cells by tumoral hepatocytes.

Hepatocellular carcinoma (HCC) is the main type of primary liver cancer, and it develops from hepatocytes. The stroma of HCC is infiltrated by myofibroblasts. In other settings, such as liver fibrosis, myofibroblasts are derived mainly from the activation of hepatic stellate cells (HSC). In this study, we investigated whether tumoral hepatocytes were able to activate HSC. HSC were isolated from normal rats and were plated in dishes coated with Matrigel, to prevent their spontaneous activation. HSC were exposed to conditioned medium (CM) from the rat HCC lines Fao and H5. Tumor cell CM elicited major morphologic changes, such as spreading and generation of cytoplasmic processes. Fao and H5 CM increased HSC proliferation to 1.60 and 1.76 times control values, respectively. The expression of alpha-smooth muscle actin was low or undetectable in control cells and was markedly increased by both tumor cell CM but not by normal rat hepatocyte CM. Desmin expression was also enhanced. Gelatinase A secretion was significantly increased 1.20-fold by Fao CM and 1.55-fold by H5 CM. Expression of beta-type platelet-derived growth factor receptor mRNA was increased 5.8-fold by H5 CM but was decreased to 13% of control levels by Fao CM. HSC activation by tumor cell CM was not prevented by urokinase or matrix metalloproteinase inhibitors, suggesting that Matrigel degradation was not central to the activation process. Finally, a blocking antibody to transforming growth factor-beta1 did not impede Fao CM-induced activation but significantly blocked the increase in matrix metalloproteinase-2 expression induced by H5 CM. Our results show that tumoral rat hepatocyte CM is able to induce the activation of rat HSC in culture. The lack of induction of beta-type platelet-derived growth factor receptor mRNA by Fao CM indicates that, in some cases, tumor-induced activation differs from classic fibrosis-type activation. Our data thus suggest that HSC recruitment and activation in HCC could be under the control of tumor cells.

Animals↗
PubMed1998

Localized fibrous tumor of the liver: imaging findings.

We report the imaging of a localized fibrous tumor of the liver, focusing on color Doppler US, CT, MR imaging, and angiographic findings. We discuss the differential diagnosis of such a rare, benign lesion of the liver. Detailed imaging of this tumor has not been reported in the literature previously.

Aged↗
PubMed1998

Case report: secondary biliary cirrhosis possibly related to congenital hepatic fibrosis. Evidence for decreased number of portal branch veins and hypertrophic peribiliary vascular plexus.

A 30-year-old man with presinusoidal portal hypertension was transplanted for cryptogenic cirrhosis. On the explanted liver, few intrahepatic stones, biliary cirrhosis, chronic cholangitis of the large bile ducts and a peculiar proliferation of small dilated bile ducts at the periphery of the portal tracts led to the diagnosis of secondary biliary cirrhosis and cholangitis, possibly linked to ductal plate malformation, including congenital hepatic fibrosis associated with a minor form of Caroli's disease. Ex vivo portogram and histology showed the paucity of portal vein branches and the hypertrophy of the peribiliary vascular plexus. This hypertrophy, which has been reported in livers with presinusoidal hypertension, is another indirect argument to suggest the diagnosis of congenital hepatic fibrosis.

Adult↗
PubMed1998

Aspirin and heparin prevent hepatic blood stasis and thrombosis induced by the toxic glycoprotein Bolesatine in mice.

Bolesatine is a toxic glycoprotein isolated from Boletus satanas Lenz, which inhibits protein synthesis in vivo and in vitro. The LD50 (24 h) is 1 mg /kg bw (i.p.), in mice and rats. When given i.p. to mice (0.1 - 1.0 mg/kg bw) bolesatine induced thrombi and blood stasis in the liver, 5 - 21 h after injection, and modifications of the number of blood corpuscles in peripheral blood. These effects were efficiently reversed by aspirin, ticlopidin and heparin (as attested by histology and electron microscopy) which however failed to prevent death in animals given lethal doses. Together, these results showed that the death of bolesatine poisoned animals given high doses, was rather due to a combination of thrombosis and other toxic effects. In addition, they suggest that these antithrombotic drugs may overcome cases of human poisoning, with low exposures of this boletus, showing a hypertension probably due to mechanical obstruction which resists normal therapy.

Agglutination↗
PubMed1997

Extracellular matrix composition and integrin expression in early hepatocarcinogenesis in human cirrhotic liver.

Extracellular matrix (ECM) plays a major role in cell differentiation, proliferation, and gene expression, both in physiological and in pathological conditions. Immunohistochemistry has been used to investigate modifications of ECM and related receptors, the integrins, in 26 small nodular lesions developed in human cirrhotic livers, on the basis that these lesions could represent sequential steps of hepatocarcinogenesis: the lesions were 16 macroregenerative nodules (MRNs), either of ordinary (n = 5) or atypical (n = 11) type, and ten small (< 15 mm) hepatocellular carcinomas (HCCs). Data were compared with those obtained in the surrounding cirrhotic tissue, in large HCCs, and in normal liver. The results indicate similarities between ordinary MRNs and cirrhosis, on the one hand, and between atypical MRNs and small HCCs, on the other. Strong and homogeneous deposition of collagen type IV and laminin in sinusoids and overexpression of alpha 6 integrin by sinusoidal cells and hepatocytes were especially noticeable in dysplastic areas characteristic of atypical MRNs, as in small HCCs. In addition, the staining of alpha 2 and alpha 6 integrins in MRNs revealed the presence of widespread atypical ductular proliferation expanding from periportal and perinodular areas, containing epithelial cells with transitional (hepato-biliary) phenotype. These findings suggest a transition from atypical MRNs to small HCCs and a possible role for liver epithelial precursor cells ('stem cells') in the development and evolution of MRNs.

Carcinoma, Hepatocellular↗
PubMed1997

Prevalence of liver cell dysplasia and association with HCC in a series of 100 cirrhotic liver explants.

BACKGROUND/AIMS: Liver cell dysplasia of large (LLCD) and small (SLCD) cell types may represent a premalignant change. We sought to evaluate their prevalence, relationship with the gross type of cirrhosis, aetiology of liver disease, and the presence of hepatocellular carcinoma in a series of cirrhotic livers. METHODS: The presence and pattern of SLCD and LLCD were evaluated by careful histological analysis in 100 consecutive cirrhotic livers of viral (49%) or non viral (51%) aetiology, and with or without hepatocellular carcinoma. Prevalences were compared using Chi-square or Fisher's tests; relative risk for hepatocellular carcinoma was evaluated by the odds ratio. RESULTS: Dysplasia was found in 82/100 of livers. Eighty-one had LLCD, with (n=49) or without (n=32) associated SLCD. SLCD alone was found in only one case. LLCD and SLCD tended to be more frequent and extensive in mixed or macronodular cirrhosis than in micronodular cirrhosis. LLCD was significantly more frequent and extensive in cirrhosis due to hepatitis B, as was SLCD in cirrhosis due to hepatitis B virus or biliary diseases, where it showed a different pattern (focal vs diffuse, respectively). LLCD and SLCD were both significantly associated with the presence of hepatocellular carcinoma, even of small size. Small foci of SLCD and widespread LLCD were the two conditions which showed the strongest association with hepatocellular carcinoma, with odds ratios of: 6.33 and 3.88, respectively. Widespread SLCD was not relevant for hepatocellular carcinoma in biliary diseases. CONCLUSIONS: Liver cell dysplasia may be considered an additional risk factor for hepatocellular carcinoma in patients with cirrhosis and should be looked for in biopsies. Widespread LLCD and SLCD with a focal pattern are particularly relevant for hepatocellular carcinoma, whereas widespread small cell changes found in biliary diseases seem to have a different biological significance.

Carcinoma, Hepatocellular↗
PubMed1997

Human hepatic myofibroblasts increase invasiveness of hepatocellular carcinoma cells: evidence for a role of hepatocyte growth factor.

The stroma of hepatocellular carcinomas (HCC) is infiltrated with myofibroblasts (MFs). Preliminary in vivo data have suggested that liver MF express hepatocyte growth factor (HGF), a cytokine that has been implicated in several tumor models. Our aim was to investigate the role of MF and HGF in HCC. Cultured liver MF expressed HGF messenger RNA (mRNA) and secreted HGF in their medium, as shown by Western blot, immunoprecipitation, and enzyme-linked immunosorbent assay (ELISA). Addition of MF-conditioned medium to the HepG2 HCC cell line induced cell scattering. This was associated with a decrease in cell proliferation. MF also increased about 100-fold the ability of HepG2 to invade Matrigel. Increased invasiveness was also shown for HuH7 cells, but no scattering was observed and cell proliferation was stimulated. All the effects of MF on both tumor cell types were blocked by addition of an antibody to HGF and they all could be reproduced by adding recombinant HGF to the tumor cells. RT-PCR and Western blot analysis confirmed that both tumor cell lines expressed c-met, the receptor for HGF. The effects of MF-conditioned medium were not reproduced by acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor (EGF), transforming growth factor-beta1 (TGF-beta1), or platelet-derived growth factor (PDGF-BB). Reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that HGF was expressed in human HCC. Our data show that human liver MF act on HCC cells to increase their invasiveness and suggest that MF-derived HGF could be involved in the pathogenesis of HCC.

Actins↗
PubMed1997

Case report: incomplete septal cirrhosis with liver cell dysplasia.

A 60-year-old woman was transplanted for end-stage alcoholic cirrhosis. The diagnosis of cirrhosis was made 13 years earlier on the basis of features of portal hypertension and a wedge liver biopsy. Liver function tests were subnormal except for a low prothrombin time. Unproven possible alcohol abuse was the only aetiological factor. Her condition remained unchanged until transplantation, despite complete abstinence. Histological examination of the explant showed incomplete septal cirrhosis associated with distal obstructive portal venopathy, cirrhotic nodules predominantly in the subcapsular areas and nodular regenerative hyperplasia with septal fibrosis elsewhere. In addition, there were areas of large and small liver cell dysplasia. This observation shows the difficulty in making a diagnosis of incomplete septal cirrhosis and the hypothetical link between liver cell dysplasia (which has never been reported in incomplete septal cirrhosis but is well known to be associated with hepatocellular carcinoma in cirrhosis) and rare cases of liver adenomas and carcinomas reported in patients presenting with liver vascular disorders.

Female↗
PubMed1997

Characterization of a new human liver myofibroblast cell line: transcriptional regulation of plasminogen activator inhibitor type I by transforming growth factor beta 1.

Myofibroblasts (MF) are a major effector cell type in liver fibrogenesis, where they are thought to derive from the activation of hepatic stellate cells. Cultured human MF, grown from liver explants, retain most of the in vivo characteristics of liver MF but are in limited supply. A continuous MF cell line would therefore be valuable in studying human liver fibrogenesis. For this purpose, we sought to immortalize human liver MF with polyoma virus large T antigen. MF were obtained from explants of human liver and transfected with a plasmid containing the coding sequence of polyoma virus large T antigen. This procedure yielded an activity growing cell line, designated GREF-X, which did not express large T antigen. Nevertheless, this cell line has been passaged repeatedly for almost 1 year and is thus likely immortalized. The morphology of GREF-X resembles that of primary liver MF. These cells have a doubling time of approximately 72 hours and are density-inhibited, and their growth is serum-dependent. Moreover, GREF-X cells do not grow in soft agar or induce tumors in nude mice, suggesting that they are not transformed. They stain positively for MF markers, such as smooth muscle alpha-actin and vimentin; express collagens type I, IV, V, and VI, fibronectin, and laminin: and secrete matrix-metalloproteinase-2. In addition, GREF-X cells are able to take up and esterify [3H]retinol, suggesting that they actually derive from hepatic stellate cells. Finally, these cells respond to transforming growth factor-beta 1, a major mediator of liver fibrogenesis, by increasing secretion of fibronectin and plasminogen activator-inhibitor type 1. Transient transfection experiments showed that plasminogen activator-inhibitor type 1 regulation, by transforming growth factor-beta 1, was transcriptional. We believe, therefore, that GREF-X would be a useful tool for studying the pathophysiology and pharmacology of liver fibrogenesis.

Actins↗
PubMed1996

Human Kupffer cell recognition and phagocytosis of apoptotic peripheral blood lymphocytes.

Cells undergoing apoptosis are recognized and rapidly phagocytosed by macrophages before their degradation, thus preventing the inflammatory reaction and protecting tissues from the damaging effects of released potentially harmful intracellular contents. In spite of growing interest in the mechanisms leading to the engulfment of apoptotic cells, the molecular bases by which an apoptotic cell is recognized are not entirely understood. Among the several potential mechanisms by which a macrophage can identify a cell as apoptotic, the data reported in the present paper support the idea that Kupffer cells phagocytose apoptotic cells by means of lectin-like receptors. Human Kupffer cells, which possess galactose-specific binding sites, can recognize and phagocytose peripheral blood lymphocytes undergoing apoptosis after heat shock (43 degrees C) or cycloheximide treatment, but not normal living peripheral blood lymphocytes. The putative structure by which apoptotic peripheral blood lymphocytes are targeted as "edible" could be the molecular changes in the plasma membrane, In fact, our experiments indicate that the membranes of apoptotic peripheral blood lymphocytes express increased amounts of N-acetylgalactosamine, D-galactose, and mannose residues when compared with membranes of normal PBL. Phagocytosis was inhibited by adding to the culture medium sugar cocktail solution (glucose, N-acetylgalactosamine, methyl mannopyranoside, fucose, 80 mM final concentration) or to a lower extent by desialylated glycoproteins (lactosylated bovine serum albumin, asialofetuin, 2 mg/ml final concentration), but not by nondesialylated glycoproteins (fetuin, 2 mg/ml final concentration, bovine serum albumin, 20% final concentration). In addition, phagocytosis of apoptotic peripheral blood lymphocytes by human Kupffer cells was a very rapid process, being almost entirely completed within 15 min of incubation.

Apoptosis↗