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Biomedical subjects

C Balabaud

Publications and source records attributed to C Balabaud.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1996

Morphology of hepatic stellate cells in patients with fulminant or subfulminant hepatitis requiring liver transplantation.

Hepatic stellate cells were studied by immuno-cytochemistry with anti smooth muscle alpha-actin antibody (an activation marker for these cells) and electron microscopy, in eleven patients transplanted for fulminant or subfulminant hepatitis. Numerous smooth muscle alpha-actin positive cells were found in necrotic areas. In both fulminant and subfulminant hepatitis, hepatic stellate cells appeared enlarged, often irregular, with spikes. There were numerous signs of activation and many contained numerous small lipid droplets. In the cases of fulminant hepatitis, hepatic stellate cells presented, at times, some subcellular damage. Hepatic stellate cells processes, often in several layers, displayed numerous cytoplasmic microfilaments with conspicuous dense plaques below the plasma membrane. Hepatic stellate cells were never surrounded by a basement membrane. The extracellular matrix was loose and granulofibrillar. In areas of multiacinar nodules (in cases of map-like pattern), hepatic stellate cells were grossly normal. These results are in agreement with in vitro data showing that acutely damaged hepatocytes activate hepatic stellate cells but do not fully transform them into myofibroblasts.

Acetaminophen↗
PubMed1995

Variations in the expression of cell-adhesion molecules on liver-associated lymphocytes and peripheral-blood lymphocytes in patients with and without liver metastasis.

We evaluated the expression of the cell-adhesion molecules (CAM) that might be involved in liver-associated lymphocyte (LAL) contacts with other sinusoidal cells and/or be responsible for natural-killer(NK)- and lymphokine-activated killer(LAK) activity in patients with liver metastasis. The LAL population was isolated by sinusoidal high-pressure lavage from partial hepatectomies obtained from patients operated for metastases (n = 13) and benign liver tumors (n = 9). Surface expression of the beta-2-integrin chains (CD11a, CD11b, CD11c and CD18), and the beta-I-integrin chains (CD49b, CD49d, CD49f and CD29), as well as that of members of the immunoglobulin superfamily (CD2, CD54, CD56 and CD58), were analyzed by one- or two-color flow cytometry. Quantitative and qualitative differences were observed in both groups of patients in the expression of CAM between LAL and peripheral blood lymphocytes (PBL). LAL were characterized by an increase in the percentage of CD11b-, CD49b-, CD49d-, CD54-, CD56- and CD58-positive cells in comparison with PBL. Fluorescence values for CD2, CD11a, CD18 and CD56 were higher in LAL than in PBL. Moreover, the population expressing these antigens of differentiation presented a bimodal distribution (dim and bright): in LAL, as opposed to PBL, the percentage of cells with a bright phenotype was greater than of those with a dim one. The increase in CAM expression on LAL could be due to the influence of the liver sinusoidal micro-environment. Results were more unexpected for the comparison between benign and malignant tumors. No difference was found in CAM expression on LAL between these 2 categories. Consequently, it cannot be this factor that explains the decrease in LAK activity of LAL in patients with metastasis.

Adult↗
PubMed1995

Adenomatous hyperplasia in cirrhotic livers: histological evaluation, cellular density, and proliferative activity of 35 macronodular lesions in the cirrhotic explants of 10 adult French patients.

We examined 41 consecutive cirrhotic liver explants from French patients for the presence of nodules of adenomatous hyperplasia (AH) and then analyzed these lesions, together with underlying cirrhosis (C) and associated hepatocellular carcinoma (HCC), for various histological parameters, cellular density, and proliferative activity. Thirty-five AHs were identified in 10 livers (prevalence, 24%); seven of 10 were HCV positive. Hepatocellular carcinoma was more frequent in patients with AH than in patients without. The AHs consisted of 17 ordinary (OAH) and 18 atypical (AAH) adenomatous hyperplasia lesions. There was a malignant focus in five of the 18 AAHs. Wide areas of large liver cell dysplasia were frequent in OAH but never found in AAH. Obvious steatosis was frequent in HCC but exceptional in AAH and absent in OAH. There was a significant increase in cellular density in AAH and HCC as compared with C and OAH. Proliferative cell nuclear antigen immunostaining similarly showed an increase in proliferation from OAH or C to AAH and HCC. These data suggest that, in Europe as in Japan, one pathway of hepatocarcinogenesis is a multistep process in which AAH should be considered as a premalignant lesion very close to grade I HCC, while OAH seems to correspond to a regenerative nodule with limited proliferative ability.

Adenoma↗
PubMed1995

Progression from idiopathic portal hypertension to incomplete septal cirrhosis with liver failure requiring liver transplantation.

We report the case of a 30-year-old male patient suffering from what was initially thought to be end-stage cryptogenic cirrhosis with portal hypertension and liver failure, who underwent liver transplantation. Histological examination of the surgical specimen showed incomplete septal cirrhosis. At the age of 17 this patient had presented pancytopenia and splenomegaly, which were treated by splenectomy. The surgeon discovered portal hypertension. Re-examination of the wedge liver biopsy taken at this time revealed features of idiopathic portal hypertension. This case clearly shows that incomplete septal cirrhosis may be a late manifestation of idiopathic portal hypertension. The presence of sinusoidal dilatation and peliosis as well as early evidence of fibrosis which are already visible on the initial biopsy and are still present on the late specimen, are indirect evidence of a continuous process which ultimately led to incomplete cirrhosis with liver failure.

Adult↗
PubMed1995

Human liver-associated lymphocytes: an overview.

Morphological and phenotypical data indicate that liver sinusoids contain a heterogeneous population of lymphocytes of which large granular lymphocytes are only one element. It is suggested that the term of liver-associated lymphocytes (LAL), which encompasses all sinusoidal lymphocytes, be used for this fourth sinusoidal cell type. Studies realized by flow cytometry on isolated cells have shown that human LAL differ phenotypically from peripheral blood lymphocytes (PBL). LAL are characterized by a three-fold increase in the percentage of cells presenting the CD56 antigen, a natural killer (NK) marker, but also an increase in the percentage of CD8 cells and a decrease in the percentage of CD4. Furthermore, within the CD56+ LAL population, 95% of cells are CD3+/- CD16-, whereas the majority of CD56+ cells in PBL are CD3-/CD16+. These differences do not seem to depend on liver pathology since no differences were found in the LAL phenotype, for all markers analysed, between patients with liver metastasis or with benign liver tumours. Liver sinusoids also harbour T cells bearing the gamma/delta chains with a repertoire of V gene arrangements which differs from that found in PBL from the same patients, confirming a site-specificity. Functionally, LAL were shown to possess a higher level of NK cell activity against K-562 cells than PBL. LAL also expressed a lymphokine activated killer (LAK) activity against NK-resistant cell lines (Raji cells), whereas no such activity was detected in PBL from the same patients. Interestingly, LAK-activity from LAL isolated from patients with liver metastases was dramatically decreased compared to that from LAL isolated from patients with benign liver disease. The level of LAK activity of LAL situated distant to the malignant tumour was higher than that obtained from LAL close to the tumour, thus suggesting that cytotoxic lymphocyte capabilities could be inhibited by tumoral cells. LAL differ, both quantitatively and qualitatively, from PBL in the expression of cellular adhesion molecules. Precise mechanisms of their homing or in situ differentiation must still be elucidated.

Cytotoxicity, Immunologic↗
PubMed1995

Ultrastructure of human Kupffer cells maintained in culture.

Sinusoidal cells were isolated by collagenase perfusion and metrizamide gradient centrifugation, from liver resected for partial hepatectomy performed under warm ischemic conditions. Kupffer cells were then separated from this population by centrifugal elutriation. Isolated Kupffer cells showed good viability, with the typical features of Kupffer cells and were engaged in the endocytosis of foreign particles. They showed numerous morphological criteria of activation. However, cultured Kupffer cells were no longer in an activated state. Kupffer cells were preserved in maintenance cultures for 2 weeks. Purity of these cultures was to 93-97%. During culture, Kupffer cells retained their ultrastructural characteristics and were active in the endocytosis of latex beads and opsonized zymosan particles. It is thus possible that partial hepatectomy performed under warm ischemia could provide valuable material for the study of Kupffer cells in vitro.

Adult↗
PubMed1995

Expression of cell adhesion molecules on liver-associated lymphocytes and their ligands on sinusoidal lining cells in patients with benign or malignant liver disease.

Liver sinusoids, in contrast with the capillaries of other tissues, contain large numbers of sequestered lymphocytes. These blood-borne cells preferentially home in the liver. The mechanism regulating the recruitment of these cells and molecular regulation of the recognition of endothelial cells is as yet unclear. The present study sought to evaluate the cell adhesion molecules on human liver-associated lymphocytes and their ligands on sinusoidal lining cells in 29 patients undergoing partial hepatectomy for liver tumors. Liver-associated lymphocytes and peripheral blood lymphocytes were analyzed by flow cytometry using monoclonal antibodies. Frozen sections of liver tissue were stained according to alkaline phosphatase anti-alkaline phosphatase method. Cytometric analysis showed that virtually all liver-associated lymphocytes expressed on their surface the cell adhesion molecules LFA-1 and VLA-4. This liver-associated lymphocyte population also presented a significantly higher percentage of Mac 1, ICAM-1, and LFA-3 and an increased surface expression of LFA-1, LFA-2, and NCAM in comparison with peripheral blood lymphocytes. It was likewise shown that sinusoidal cells express ICAM-1, ICAM-2, ICAM-3, VCAM-1 and LFA-3 ligands. Liver-associated lymphocytes thus strongly express a number of different adhesion molecules. The corresponding ligands were also detected on sinusoidal lining cells. LFA-1 and VLA-4 would seem to be important pathways of temporary lymphocyte-endothelial adhesion in liver sinusoids.

Adenoma↗
PubMed1995

Transformation of sinusoids into capillaries in a rat model of selenium-induced nodular regenerative hyperplasia: an immunolight and immunoelectron microscopic study.

The oral administration of selenium (Se) to young rats induces, over a 2-month period, the formation of nodular regenerative hyperplasia with sinusoidal damage around nodules. Perinodular areas located in zone 1 comprise atrophic hepatocytes and capillarized sinusoids without fibrosis. We used this unique model of capillarization without fibrosis to investigate the temporal relationship between the process of capillarization and changes occurring in the deposition of components of the extracellular matrix. After 2 weeks of intoxication, type III collagen and fibronectin were stable, but laminin and type IV collagen had increased in zone 1, resulting in the formation of septae between portal tracts. Even at 8 weeks, these two components still formed the principal deposits in perinodular zones. Electron microscopy showed already at 1 week in zone 1 that part of the endothelial wall had detached from hepatocytes. Sinusoidal endothelial cells progressively acquired certain of the characteristics of a vascular endothelium, some proliferated, and perisinusoidal cells transformed into myofibroblasts, surrounded by deposits of laminin and type IV collagen. These results indicate that both laminin and type IV collagen are involved in capillarization without fibrosis and in angiogenesis; fibronectin would not seem to play a role.

Animals↗
PubMed1994

Preservation of human liver grafts in UW solution. Ultrastructural evidence for endothelial and Kupffer cell activation during cold ischemia and after ischemia-reperfusion.

Biopsies taken from 13 human liver grafts at different stages of the transplantation process were used for study of the morphology of sinusoidal cells prior to harvesting (5 biopsies), after preservation in UW solution (10 biopsies), and after complete revascularization (13 biopsies). The mean cold ischemic period was 12 h 30. Immediate follow up was uneventful and the mean peak of post-operative transaminases below 1300 IU/l. Biopsies were perfusion-fixed by the transparenchymal route to ensure satisfactory ultrastructural results. There were no loose sinusoidal endothelial cells in the lumen and no signs of cellular death. Some endothelial cells presented signs of activation at the end of the preservation period, and even more after revascularization, with numerous lucent vacuoles resembling endosomes in the cytoplasm. Kupffer cells also presented signs of activation, particularly after reperfusion. The retraction of endothelial cell processes which formed large gaps during cold ischemia proved to be partly reversible after reperfusion. Signs of endothelial cell damage with gaps and partial rupture of the plasmic membrane were also observed, particularly after revascularization, in areas which contained numerous inflammatory cells adhering to the wall. The Disse space was not generally enlarged and contained no inflammatory cells. The sinusoidal pole of hepatocytes was occasionally damaged with the formation of blebs. These results strongly suggest that any drug or preservation solution that will inhibit endothelial and Kupffer cell activation could be beneficial in the prevention of preservation and reperfusion injury.

Adenosine↗
PubMed1994

Detection of cell-adhesion molecules on human liver-associated lymphocytes.

Liver-associated lymphocytes (LAL) from human liver are phenotypically and functionally different from peripheral blood lymphocytes (PBL). Phenotypically, they are mainly represented by the CD3+/-CD56+ phenotype and functionally they spontaneously possess lymphokine-activated killer (LAK) activity. In this study we evaluated the expression of cell-adhesion molecules (CAM) which could be involved in LAL contacts with other sinusoidal cells and/or be responsible for the LAK activity. The LAL population was isolated by sinusoidal high-pressure lavage from partial hepatectomies obtained from patients operated on for benign liver disease (n = 6). Surface expression of the beta 2 integrin chains (CD18, CD11a, CD11b, CD11c), as well as that of members of the immunoglobulin superfamily (CD2, CD54, CD56, CD58), were analysed by one or two-colour flow cytometry. Quantitative and qualitative differences were observed in the expression of CAM between LAL and PBL. LAL were characterized by an increase in the percentages of CD11b+, CD54+, CD56+ and CD58+ cells and a decrease in the percentage of CD2+ cells compared to PBL. Fluorescence intensity values for CD2 and CD56 were higher in LAL than in PBL. Moreover, CD11a/CD18 cells presented a bimodal distribution (dim and bright) in both PBL and LAL; whereas these two subpopulations were equally represented in PBL, the number of bright cells was significantly greater (> 80%) in LAL. The increase in CAM expression (percentage of positive cells and intensity of fluorescence) on LAL combined with their increase in natural killer (NK) and LAK activities already reported, support the idea that, at least some, LAL might be, compared to PBL, in an activated state in vivo.

Antigens, CD↗