Jean-Yves Scoazec

Expression of cytokine-dependent immune adhesion molecules by hepatocytes and bile duct cells in chronic hepatitis C

BACKGROUND/AIMSnThe pathogenesis of liver cell injury in chronic hepatitis C is poorly understood. To test whether immune-mediated mechanisms might be involved in the pathogenesis of liver cell injury during infection by hepatitis C virus, the expression of cytokine-dependent immune molecules by hepatocytes and bile duct cells during chronic hepatitis C was studied.nnnMETHODSnIn 35 patients, expression of class I and II HLA antigens, intercellular adhesion molecule (ICAM) 1, and lymphocyte function antigen (LFA) 3 was studied by immunohistochemistry and scored by a semiquantitative grading system. Statistical analysis was performed using Spearmans test and t test.nnnRESULTSnClass I HLA antigens were induced on hepatocytes in 20 cases. In all cases, HLA-DR, ICAM-1, and/or LFA-3 were detected on hepatocytes in piecemeal necrosis and intralobular clusters. Bile duct cells expressed HLA-DR in 32 cases and ICAM-1 and LFA-3 in 14 cases. Expression levels of immune molecules on hepatocytes correlated with aminotransferase activity (P < 0.035), histological activity (P < 0.001), and score of necrosis (P < 0.01). ICAM-1 expression on hepatocytes was higher in patients with intraportal lymphoid nodules (P = 0.005). Expression levels of ICAM-1 and LFA-3 on bile ducts correlated with the severity of bile duct damage (P < 0.015).nnnCONCLUSIONSnThese results suggest the involvement of immune-mediated mechanisms in the pathogenesis of liver cell injury in chronic hepatitis C.

The plasma membrane polarity of human biliary epithelial cells: In situ immunohistochemical analysis and functional implications

BACKGROUND/AIMSnIn transporting epithelia, like the biliary epithelium, most plasma membrane proteins present a polarized distribution, essential for the maintenance of the structural and functional properties of the epithelium. We therefore analyzed the expression of polarized plasma membrane proteins by human biliary epithelial cells in order to compare them with other transporting epithelial cells and to search for differences in plasma membrane protein expression between their different anatomical subsets.nnnMETHODSnWe designed an in situ immunohistochemical study of the various anatomical compartments of the human biliary tract in order to assess the pattern of expression of selected polarized plasma membrane proteins, including integrin receptors, ectopeptidases, membrane transporters and GPI-linked proteins.nnnRESULTSnAll biliary epithelial cells expressed the same repertoire of integrins, except for integrin chain alpha5, restricted to the intra-hepatic compartments. All biliary epithelial cells expressed the following apical ectopeptidases: aminopeptidase-N, neutral-endopeptidase, dipeptidyl-peptidase IV. All biliary epithelial cells expressed the membrane transporter Na+ K+-ATPase, restricted to the basolateral domain, and the apical transporters CFTR and MDR-1. The apical AE2 anion exchanger was restricted to the small intra-hepatic bile ducts and the gallbladder. The GPI-linked protein protectin was basolateral in the intrahepatic bile ducts and apical in the gallbladder.nnnCONCLUSIONSnThe structural organization of the plasma membrane of biliary epithelial cells is very similar to that of other simple epithelia and exhibits a limited degree of heterogeneity.

Functional hepatocellular heterogeneity for the production of plasma proteins

It is now well established that hepatocytes are the main liver cells responsible for the synthesis of plasma proteins produced by the liver. That these cells are not specialized in the production of the different plasma proteins is also well established. Presently the point still debated is whether a functional hepatocellular heterogeneity exists for plasma protein synthesis as for many other hepatocyte functions. Several physiological and pathological situations suggest that this heterogeneity takes place in the hepatocytes of two opposite hepatic lobular zones, the periportal and centrilobular zones. However, this zonal difference, which supposes different regulatory mechanisms, must be confirmed by techniques other than the now classical immunocytochemistry or the in situ hybridization technique recently proposed for the demonstration of mRNAs in hepatocytes. Another hepatocellular heterogeneity, the intercellular heterogeneity, which can be observed in the same lobular zone, is more difficult to analyze, but shows that from hepatocyte to hepatocyte a variation exists in the synthesis of a given plasma protein.

Human allograft vein failure: Immunohistochemical arguments supporting the involvement of an immune-mediated mechanism

The aim of this study was to search for signs suggestive of an ongoing immune-mediated reaction in failed human cryopreserved venous allografts. In 15 samples, the authors analyzed: (1) the pattern of morphological changes; (2) the density, distribution, and phenotype of leukocytic infiltrate; and (3) the expression of class II major histocompatibility complex (MHC) antigens and inducible adhesion molecules. Two groups of samples could be recognized. In samples explanted before 3 months after grafting, the structure of the vessel wall was preserved. A dense leukocytic infiltrate was present within the intima and around the numerous vasa vasorum located in medial and adventitial layers. Class II MHC antigens and cytokine-dependent molecules were induced on endothelial cells lining the vasa vasorum and on residual smooth muscle cells. In samples explanted after 3 months of evolution, the vessel wall has lost its normal structure and contained few vasa vasorum. A few leukocytes were detected around capillary vessels located in the peripheral connective tissue surrounding the graft. Class II MHC antigens and adhesion molecules were induced on endothelial cells lining the peripheral capillary vessels. These results suggest the involvement of an immune-mediated mechanism at the early stage of the evolution of failed human venous allografts.

Soluble intercellular adhesion molecule 1 in umbilical cord serum: Potential for the diagnosis of neonatal infections

Objective: To evaluate the diagnostic relevance to neonatal infections of the soluble intercellular adhesion molecule 1 (sICAM-1) cord serum level. Methods: The case-control study included 66 term newborn infants with and without risk factors for neonatal infections. Cord blood serum determinations of white blood cell count, C-reactive protein, fibrinogen, and sICAM-1 were systematically performed associated with bacterial cultures from placenta, ears, and gastric fluids. Results: 6 of 33 infants (18.2%) with risk factors were infected, and 13 (39.4%) were colonized. Two infants included in the group without infection risk factors (n = 33) were colonized. No difference in sICAM-1 cord serum levels was found according to the presence of premature rupture of membrane, fetal tachycardia >160 bpm, meconial amniotic fluid, and duration of labour >10 h. No difference in sICAM-1 was noted between infected and non-infected infants. The cord serum levels of sICAM-1 were significantly higher in infants after forceps extraction (p = 0.01). A correlation was observed between sICAM-1 and C-reactive protein cord serum levels (p = 0.004, r = 0.371) and between sICAM-1 level and neutrophil count (p = 0.01, r = 0.489). Conclusions: Our results suggest that cord serum sICAM-1 determinations have no diagnostic relevance to neonatal infection. The increase of sICAM-1 cord serum levels in infants after forceps extraction suggests its potential to evaluate cerebral trauma or hypoxia.

Coexpression of periportal and perivenous enzymes in rat hepatocytes after experimental bile duct ligation: Comparison with intrasplenically transplanted hepatocytes

The coexpression of normally periportal and perivenous markers has been described in heterotopically transplanted hepatocytes. To determine whether such a coexpression might also occur in hepatocytes retaining their original intrahepatic location, we compared in bileduct-ligated livers and intrasplenically transplanted hepatocytes, the expression and distribution of the predominantly periportal glucose-6-phosphatase, succinate dehydrogenase, and lactate dehydrogenase, the predominantly perivenous glutamate dehydrogenase, NADPH-dehydrogenase, and β-hydroxybutyrate dehydrogenase, and the strictly perivenous glutamine synthetase. The coexpression of high levels of the two periportal markers glucose-6-phosphatase and lactate dehydrogenase and of the perivenous marker NADPH dehydrogenase was observed in two situations: in clusters of hepatocytes isolated within the ductular proliferation in bile-duct-ligated livers and the majority of intrasplenically transplanted hepatocytes. The expression of glutamine synthetase was different according to the site. The protein was observed in certain intrasplenically transplanted hepatocytes bordering the splenic vessels but was never detected in hepatocyte clusters found in bile-duct-ligated livers. Our study therefore suggests that the coexpression of periportal and perivenous markers in the same hepatocytes is likely to be a non-specific consequence of the loss of the normal connections of hepatocytes with the normal liver microcirculation.

E‐cadherin and CD44 expression in cervical intraepithelial neoplasia: Comparison between HIV positive and HIV negative women and correlation with HPV status

AIMSnWe aimed to compare the expression patterns of E-cadherin and CD44 isoforms in cervical intraepithelial neoplasia (CIN) between patients with or without infection by the human immunodeficiency virus (HIV).nnnMETHODSnAn immunohistochemical analysis using the monoclonal antibody HECD-1 against E-cadherin and the monoclonal antibodies 2C5, binding to CD44s and all the variants encoded by exons 3 to 10, 3G5, specific for CD44v3 and 2F10, and specific for CD44v6, was performed in formalin-fixed, paraffin-embedded samples of 138 CIN (74 from HIV-negative and 64 from HIV-positive patients).nnnRESULTSnIn HIV-negative patients, the mean percentages (+/-SD) of E-cadherin-positive cells in CIN of grades I, II, and III were, respectively, 33% +/- 4, 63% +/- 5, and 91% +/- 9. The difference was statistically significant between the three groups of tumors (P < 0.0001). In HIV-negative patients, the mean percentages (+/-SD) of CD44-positive cells in CIN of grades I, II, and III were, respectively, 37% +/- 7, 57% +/- 8, and 90% +/- 11. The difference was statistically significant between the three groups of tumors (P < 0.0001). No difference in E-cadherin and CD44 expressions was noted between HIV+ and HIV- women. Further analysis showed no relation between E-cadherin or CD44 expression and the HPV status and CD4 T cell serum levels.nnnCONCLUSIONnOur study confirms that alterations in E-cadherin and CD44 expression in CIN depend on the histological grade but suggest nondirect involvement and are not related to HIV and immune status.

The expression of cellular adhesion molecules is upregulated and co-localized with the oxidative stress in the early course of experimental acute pancreatitis

Using a novel method to demonstrate histologically the production of oxygen free radicals (OFR-s), this study investigates the possible role of cellular adhesion molecules (CAM-s) -in relation to the oxidative stressduring the early course of acute necrotizing pancreatitis (ANP). Similarly to other inflammatory pathologies, injury to the pancreatic acini supposedly results in the expression/upregulation of CAM-s on the periacinar endothelial cells as well as release of proinflammatory mediators. The adherent lenkocytes, mostly neutrophils (PMN), become activated and release OFR-s, microbicidal enzymes and more mediators to strengthen the inflammatory response. An uncontrolled inflammatory cascade may become locally and systemically deleterious. We have developed a novel technique to detect the presence and localization of OFR-s in vivo, using the cerium capture method. Reaction of OFR-s with CeC13 leads to cerium-perhydroxide precipitation. These deposits can be detected histologically by their laser reflecting properties using confocal laser scanning microscopy (CLSM) in the reflectance mode (RM). METHODS: ANP was induced in Wistar rats by retrograde infusion of taurocholate into the pancreatic duct. At different time points (1, 2, 24h) the animals were re-laparotomized and perfused with CeC13 (20mM in Hartmann solution) through the abdominal aorta, then sacrificed. Normal rats received a CeCI 3 perfusion in the same fashion and were used as controls. Pancreata were snap frozen in liquid nitrogen. Indirect immunofluorescence (FITC fluorochrome) was performed on serial frozen sections to label E-selectin, P-selectin, ICAM-1, VCAM-1, and PECAM molecules. Nuclei were colored by propidium-iodide. Simultaneous observation of CAM expression, cerium reflectance and cell type definition was performed by CLSM using multichannel detection. RESULTS: The capillaries in the pancreata of normal animals showed weak, sparse P-selectin and ICAM-1 positivity, with a constitutive expression of PECAM. Reflectance signals were negligible. At the early time points (1, 2h) of pancreatitis the tissue architecture was found to be relatively well preserved, an increase in endothelial P-selectin, and ICAM-1 immunoreactivity was observed. Strong, shining reflectance could be detected in the pancreatic microvasculature, as well as cloud-like signals over certain groups of acini. Numerous leukocytes adherent to CAM positive capillary walls were seen, however they presented small, focal, mostly intracellular reflectance signals, which were often localized at the contact points between the CAM-s and leukocytes. At 24h the samples were characterized by intense PMN infiltration, heterogeneous necrosis, strong, mostly perinecrotic P-selectin, and ICAM-1, but moderately increased E-selectin, and VCAM-1 expression. Large numbers of adherent, or already transmigrated PMN-s showed abundant intraand pericellular reflectance signals. CONCLUSION: Pancreatic endothelial CAM-s are upregulated early in ANP, and may play a role -in addition to cytokinesin the activation of adhering leukocytes. At the earliest time points the major source of OFR seems to be the pancreatic cell (xanthine-oxidase), later the activated PMN-s, thereby possibly contributing to local and distant organ damage. The CAM over-expression showed a significant spatial co-localization with the oxidative stress. The work of G. Telek was supported by a grant from IRMAD Foundation, France.