Destruction of canals of Hering in primary biliary cirrhosis

The canals of Hering (CoH), converging from the hepatic lobule onto the portal tract, connect bile canaliculi to the interlobular bile ducts, and represent the most proximal portion of the bile drainage pathway with a cholangiocyte lining. In this study we sought to ascertain whether this proximal pathway is involved by the disease process in primary biliary cirrhosis (PBC), which uniformly affects small bile ducts while sparing medium- and large-sized ducts. Ten biopsy specimens with early-stage PBC were compared with 6 normal control livers. Adjacent 4-micron-thick sections of routinely processed, formalin-fixed tissue were immunostained for CK19 and HLA-DR. Each terminal portal tract was assigned a stage: 0, normal; 1, bile duct damage or loss; 2, bile ductular proliferation; or 3, periportal fibrosis. The ratio of the number of CoH to number of portal tracts (i.e., the c/p ratio) was calculated for the control biopsies and individual portal tracts at each stage of PBC. The numbers of CoH were decreased in all stages of PBC (P <0.0001), with the fewest found around portal tracts at stages 0 and 1 and the most around portal tracts at stages 2 and 3, but never at normal levels. HLA-DR was expressed focally on bile ducts and CoH in PBC, but was absent in normal controls. We conclude that CoH are destroyed in PBC in concert with the destruction of small bile ducts. This destruction appears to be an early event, because CoH numbers are lowest around stage 0 portal tracts, which still contain normal bile ducts.     

Bile duct to portal space ratio and ductal plate remnants in liver disease of infants aged less than 1 year

AIM: To validate the bile duct to portal space ratio as an independent factor useful for the prognosis of neonatal liver disease. METHODS: We assessed the maturation of the intrahepatic bile duct system (IBDS) in 87 consecutive infants aged less than 1 year undergoing non-subcapsular, adequate (at least six portal tracts), liver needle biopsies because of hepatomegaly and/or cholestasis. The maturation of the IBDS was evaluated by immunohistochemistry with an antibody directed to cytokeratin 7 (CK7), a biliary-type intermediate filament of the cytoskeleton, and a schema showing the IBDS remodelling. We used five categories to fit the different patterns of the IBDS remodelling using the ratio between the number of bile ducts and the number of portal tracts (BD/PT) and the presence of abnormal reaction patterns (marked intra-acinar pseudorosettes and/or periportal ductular proliferation): (A) abnormal reaction patterns with any BD/PT; (B) BD/PT = 0; (C) 0.1 < or = BD/PT < 0.5; (D) 0.5 < or = BD/PT < 0.9; and (E) BD/PT > 0.9 (B-E categories: no abnormal reaction patterns). Further, we evaluated cholestasis, portal fibrosis (PF), portal inflammation (PI), giant cell transformation (GCT), and extramedullary haematopoiesis (EMH). RESULTS: We identified A-E categories in 24, 14, 17, 8, and 24 biopsies, respectively. B and C categories were frequently observed in biliary atresia (BA), A category in neonatal hepatitis (NH), A-C categories in paucity of intrahepatic bile ducts (PIBD), and E category in 'other liver diseases' (OLD). Cholestasis, PI, GCT, and EMH were more frequent in A and C, while PF was variably seen in all categories. The lowest survival rate occurred in B (Kaplan-Meier estimator). CONCLUSIONS: (1) Biliary epithelial cell patterns recapitulate the primitive stages of the IBDS maturation; (2) abnormal reaction patterns occur mainly in NH, whilst BD/PT < 0.5 in BA; and (3) lack of intrahepatic bile ducts in infants aged less than 1 year is an adverse prognostic factor independent from aetiology of neonatal liver disease.     

Morphological and immunohistochemical analysis of ductal plate malformation: correlation with fetal liver

AIMS: Ductal plate malformation (DPM) is the persistence of excess of embryonic bile duct structures in the portal tracts. Most of the congenital diseases of intrahepatic bile ducts represent examples of DPM at different levels of the biliary tree. The aim of the present study was to evaluate the histopathological spectrum and immunohistochemical properties of DPM in various paediatric liver diseases and compare them with those of the normal embryonic ductal plates of human fetuses. METHODS AND RESULTS: All paediatric liver biopsies and autopsied livers of infant deaths and stillbirths over a 5-year period (between 1996 and June 2001) were subjected to histopathological examination to identify ductal plate malformations. A detailed immunohistochemical analysis was carried out in 35 cases of ductal plate malformation and 25 abortuses by using antibodies against cytokeratin (CK)7, 8, 18 and 19, CD34 and type IV collagen. Thirty-nine cases of ductal plate malformation were identified which consisted of extrahepatic biliary atresia with DPM (n = 20), isolated congenital hepatic fibrosis (n = 9), autosomal recessive polycystic kidney disease (n = 5), congenital hepatic fibrosis with autosomal polycystic kidney disease (n = 2), Caroli's syndrome (n = 2) and one case of Ivemark's syndrome. The ductal plate cells stained with CK7, 8, 18 and 19 but not with CD34. CONCLUSION: DPM was present in all intrahepatic bile duct diseases included in this study and in about 26% of cases of extrahepatic biliary atresia. The cytokeratin immunophenotype of the ductal plate in pathological conditions is similar to that of normal embryonic ductal plates of fetuses after 20 weeks of gestation.     

Secondary sclerosing cholangitis after intensive care unit treatment: clues to the histopathological differential diagnosis

Secondary sclerosing cholangitis (SSC) is a chronic cholestatic disorder caused by mechanical, infectious, toxic, or ischemic factors. A new variant of SSC occurring after long-term treatment in intensive care units (ICU) has been recently described and characterized from the clinical point of view. The aim of this study was the histomorphological characterization of ICU-treatment-related SSC (ICU-SSC) and the definition of histological changes occurring over time based on the morphological findings. Liver biopsies of ten patients affected by ICU-SSC obtained at different time points (1.5 to 57 months) after the initial injury were analyzed. The main morphological alterations included degenerative changes of portal bile ducts, portal edema, inflammation, and fibrosis as well as biliary interface activity and bilirubinostasis. Perivenular necroses and bile infarcts were found in eight and six patients, respectively. Bile duct loss was not observed. No correlation between morphological features of biopsies and liver chemistry tests or outcome could be established. Based on the morphological observation, a possible disease-progression model starting with an initial damage of portal bile ducts (primary insult) with associated portal/periportal changes (inflammation, ductular reaction) and resulting in secondary parenchymal changes is proposed.     

Neutrophils in biliary atresia. A study on their morphologic distribution and expression of CAP37

Biliary atresia is a rare pediatric disorder that results in obstructive jaundice in early infancy. Liver biopsies are characterized histologically by cholestasis, portal inflammatory infiltrate, and marked bile ductular proliferation. We studied the distribution of neutrophils in biliary atresia in patients who have undergone the Kasai procedure. Thirteen different liver biopsies were accompanied by hilar section in eight cases. Control liver specimens were from two patients with choledochal cysts, three patients with neonatal hepatitis, and three patients with alpha-1 antitrypsin deficiency. We also studied the expression of CAP37, an antimicrobial protein present in neutrophils, using immunohistochemistry in biopsy and hilar sections. Neutrophils were present in the portal tracts in all cases and widely distributed in the parenchyma in nine cases. In six cases, infiltration of neutrophils was associated with discrete foci of liver cell necrosis. There was a significantly higher number of portal tract neutrophils in biliary atresia and choledochal cyst cases than in neonatal hepatitis and alpha-1 antitrypsin deficiency (p<0.05). All neutrophils stained diffusely and strongly with CAP37. Medium staining was also seen in the proliferating portal bile ductules in six cases. This study confirms the wide distribution of neutrophils in biliary atresia, occurring as a result of bile duct obstruction. Infiltrating neutrophils are better highlighted with CAP37 immunostain. Proliferating bile ductules may play a role in the inflammatory response in biliary atresia through expression of CAP37.     

Potential role of bcl-2 and bax mRNA and protein expression in chronic hepatitis type B and C: a clinicopathologic study.

Bcl-2 oncoprotein regulates programmed cell death by providing a survival advantage to rapidly proliferating cells, and bax protein promotes apoptosis by enchanting cell susceptibility to apoptotic stimuli. In this study, we assessed the expression of bcl-2 and bax in liver biopsies from patients with chronic hepatitis (CH) Type B (HBV) and C (HCV). The study comprised 65 liver biopsies from 65 patients with HBV (n = 37) and HCV (n = 28) and 10 normal liver biopsies as controls. The HAI score ranged from 3/18-13/18, and the fibrosis Stage, from 1-6 (7 HBV/10 HCV). Pathologic examination included the following: (1) immunohistochemical stains in paraffin sections for bcl-2 and bax protein expression, (2) Western blot analysis (bcl-2 and bax protein levels evaluation), (3) ISH (detection of bcl-2 and bax mRNA), and (4) ISH (TUNEL-ABI [apoptotic body index]). In CH cases, both bcl-2 and bax protein and mRNA were detected in portal and intralobular lymphocytes and in cholangiolar epithelial cells in interface areas and fibrous bands. Bax protein and mRNA was expressed within hepatocytes and epithelial cells of interlobular ducts in portal tracts. Bcl-2 mRNA was present in periportal hepatocytes only in cases with Stage 5-6 fibrosis. Western blot analysis showed a decreased bcl-2 and an increased bax expression toward advanced fibrotic stages. In CH cases, ABI was reverse correlated with the percentage of bcl-2 expression and was correlated directly with the percentage of bax expression (P <.001). The results of this study suggest that in cases of chronic HBV or HCV infection, bax may be involved in the hepatocyte cycle regulation during infection, whereas its expression in intraportal bile duct epithelium implies that this protein enhances susceptibility of these particular cells to apoptosis. The increased bax expression and ABI in fibrosis Stages 1-5, imply that they are responsible for hepatocytes depletion through apoptosis, during progress of liver fibrosis and fibrous tissue accumulation, until cirrhosis is established. Bcl-2 mRNA expression in periportal hepatocytes only in Stages 5 and 6 suggests that this oncogene is involved in the late stages of progressive liver fibrosis and failure and furthermore that periportal hepatocytes are resistant to apoptosis. Bcl-2 expression, in cholangioles of interface area, suggests that this oncoprotein may be involved in growth regulation of these epithelial cells. Further research is warranted to specify the exact role of apoptosis and apoptotic genes involved in liver fibrosis process in cases of chronic HBV and HCV infection. This may lead to new strategies in the management of human liver disease to prevent the progression to chronic liver failure.     

Pathology of septum formation in primary biliary cirrhosis: A histological study in the non-cirrhotic stage

Summary Bridging or incomplete septum formation, an important step leading to cirrhosis in various chronic progressive liver diseases, was examined in 231 liver biopsy specimens of primary biliary cirrhosis (non-cirrhotic stage). Incomplete septa from the enlarged portal tracts and portal to portal bridges were frequent and appeared first, while portal to central ones appeared subsequently and became frequent in the liver specimens with changes resembling cirrhosis. These septa were divided into four types histologically: ductular, lymphocytic, loose connective tissue and fibrous type. More than one type was usually found in the same specimen. The pathology of the first three types was similar to and frequently continuous with that of neighbouring periportal regions, suggesting that most of these septa were formed by the extension of periportal destructive processes. The fibrous type might be an advanced form of the other three types. Incomplete septa seemed to pinch off part of the hepatic parenchyma in a hepatic lobule; this was followed by an unusual enlargement of the portal tracts and an approximation of portal tracts and central veins. There were perivenular hepatocellular necroses on occasion. Progression of periportal hepatocellular damage may lead to septum formation and finally progress to cirrhosis, in primary biliary cirrhosis. The significance of perivenular necroses remains speculative.     

AN AUTOPSY CASE OF PRIMARY SCLEROSING CHOLANGITIS WITH SEQUENTIAL HISTOLOGIC OBSERVATIONS OF THE LIVER

A rare autopsy case of primary sclerosing cholangitis with sequential histologic observations of the liver is described. The patient, a 62-year-old female at the time of autopsy, presented with prolonged cholestasis of about 9 years duration. Initial (at 53 years) and second (at 59 years) liver biopsies disclosed fibrous enlargement of the portal tracts with loss of interlobular bile ducts, lympho-plasmacytic infiltration, a few epithelioid granulomas, piecemeal necrosis, atypical ductular proliferation and deposition of copper granules. Hypergam-maglobulinemis with elevated IgM was also noted. These clinicopathological features resembled primary biliary cirrhosis. However, no florid duct lesions were found, and absence of antimitochondrial antibodies and cholangiographic demonstration of a beaded biliary tree favored a diagnosis of primary sclerosing cholangitis. The autopsied liver disclosed sclerosis and cholangioectases of the intra- and extrahepatic biliary tree in addition to biliary cirrhosis. The histology of the biliary tree disclosed nonspecific fibrosing inflammation in the extra- and intrahepatic biliary tree. Other autopsy findings included chronic thyroiditis, sialoadenitis and pancreatitis. ACTA PATHOL JPN 38: 249–257, 1988.     

An autopsy case of primary sclerosing cholangitis with sequential histologic observations of the liver

A rare autopsy case of primary sclerosing cholangitis with sequential histologic observations of the liver is described. The patient, a 62-year-old female at the time of autopsy, presented with prolonged cholestasis of about 9 years duration. Initial (at 53 years) and second (at 59 years) liver biopsies disclosed fibrous enlargement of the portal tracts with loss of interlobular bile ducts, lymphoplasmacytic infiltration, a few epithelioid granulomas, piecemeal necrosis, atypical ductular proliferation and deposition of copper granules. Hypergammaglobulinemia with elevated IgM was also noted. These clinicopathological features resembled primary biliary cirrhosis. However, no florid duct lesions were found, and absence of antimitochondrial antibodies and cholangiographic demonstration of a beaded biliary tree favored a diagnosis of primary sclerosing cholangitis. The autopsied liver disclosed sclerosis and cholangioectases of the intra- and extrahepatic biliary tree in addition to biliary cirrhosis. The histology of the biliary tree disclosed nonspecific fibrosing inflammation in the extra- and intrahepatic biliary tree. Other autopsy findings included chronic thyroiditis, sialoadenitis and pancreatitis.     

Three-dimensional arrangement of ductular structures formed by oval cells during hepatocarcinogenesis

The three-dimensional arrangement of ductular structures formed by oval cells in rats fed 2-acetylaminofluorene (2-AAF) was studied by scanning electron microscopy (SEM) of biliary tract casts and light microscopy of sections of liver injected with india ink via the biliary tract. Both resin and india ink were well injected up to bile ductules, and the findings of each method correlated with each other. By the second week after 2-AAF administration, a few oval cells appeared in the periportal areas forming ductular structures which connected with the portal bile ducts. At the 4th week, increased ductular structures occupied two thirds of the lobule and formed networks communicating with each other, and with the portal bile ducts. At the 8th week, such ductular structures were compressed around hyperplastic nodules and appeared like a basket in biliary casts examined by SEM. Although a histochemical study of gamma-glutamyl transpeptidase revealed activity both on the luminal side of the ductular structures and hepatocytes in hyperplastic nodules, no transition was observed between these two cell populations. These results suggest that oval cells have characteristics more similar to those of biliary epithelia than of hepatocytes, and have no relation to the development of hyperplastic nodules.     

Histological features of sclerosing cholangitis in patients with chronic ulcerative colitis.

Primary sclerosing cholangitis was diagnosed radiologically in 16 of 681 patients (2.2%) with chronic ulcerative colitis in a follow up study at the gastroenterology unit in Oxford. On the basis of established histological criteria, the liver biopsy was considered diagnostic in only half of the cases. The histological findings in these cases were therefore reassessed to determine whether the accuracy of biopsy diagnosis could be improved. The most common specific histological feature was periductal concentric fibrosis of small interlobular bile ducts, even in the absence of inflammation. Other common features were bile ductular proliferation associated with diminution or absence of interlobular bile ducts. Degeneration of bile duct epithelium and diffuse infiltration of portal tracts by mononuclear cells and polymorphonuclear leucocytes were accompanying features. Piecemeal necrosis without rosette formation was found in about half the biopsies. When all these features were considered together a biopsy diagnosis of primary sclerosing cholangitis was established in 14 of 16 cases.     

Immunohistochemical detection of collagen type III and IV in relation with transformation of Ito cells in liver sinusoids of patients with reactive biliary hepatitis.

Reactive biliary hepatitis is a defined morphological entity, which is a result of chronic diseases of the gall bladder, biliary ducts or pancreas. The aim of the present study was to describe the morphology of reactive biliary hepatitis and its significance for progression of liver fibrosis, and in particular Ito cell (fat storing cell) transformation and occurrence of collagen type III and IV in the liver. Liver tissue from 19 patients with reactive biliary hepatitis was investigated light microscopically and immunohistochemically. Histologically, the liver showed features of mild to severe portal and lobular inflammation. The number of Ito cells increased periportally and pericentrally. Deposition of collagen type III and IV was increased in portal tracts, septa and perisinusoidal spaces, mainly in periportal zones of the lobules. Ultrastructurally, collagen type III immunoreactive fibrillar networks were found to be increased in the space of Disse around transitional cells. Collagen type IV immunoreactive deposits were detected around newly proliferating bile ducts in portal stroma and in the space of Disse. Ito cells were mainly transformed into transitional and myofibroblast-like cells. We discuss here the role of Ito cells and certain cytokines in the process of fibrosis of the liver in the course of reactive biliary hepatitis. It is proposed that bile acid retention in bile ducts during non-specific reactive inflammation or a gut endotoxin may cause transformation of Ito cells and increased collagen type III and IV in this type of hepatitis.     

Progression of autoimmune damage in primary biliary cirrhosis: an immunohistochemical study

Aberrant MHC Class II antigen expression and the nature of the infiltrating lymphoid cells were studied by immunohistochemical techniques in liver biopsies from 37 patients with Primary biliary cirrhosis (PBC) (11 histological stage I, 13 stage II-III, 13 stage IV) and 15 patients with chronic non autoimmune liver disease. Bile duct epithelial cells expressed HLA-DR, DP and DQ antigens in biopsies from patients with early (Stage I) PBC and less frequently in the late cirrhotic phases of the disease (Stage IV); these observations support the hypothesis that induction of Class II antigens on epithelial cells may be involved in initiating autoimmune responses towards bile duct components. The presence of cytotoxic/suppressor T cells around the bile ducts in Stage I suggests a role for cell mediated destruction of the ducts at this early stage. The nature of the chronic inflammatory cell infiltrate in the portal tracts, periportal areas and lobular parenchyma does not establish the mechanism(s) involved in disease progression. However, the lack of Class II antigen expression on hepatocytes is compatible with the hypothesis that hepatocellular damage is non-specific and may be secondary to the initial bile duct injury.     

Gadolinium chloride suppresses hepatic oval cell proliferation in rats with biliary obstruction.

Liver injury due to bile duct ligation (BDL) is histologically characterized by cholestasis, bile ductular proliferation, hepatocellular damage, portal fibrosis, and ultimately biliary cirrhosis. Stem cells within the liver may act as progenitor cells for small epithelial cells termed oval cells that can differentiate into bile duct cells or hepatocytes, whereas myofibroblasts are the principal source of collagen production in fibrosis. The aims of this study were to determine 1) whether BDL induces oval cell proliferation and 2) whether blockade of Kupffer cells affects oval cell proliferation, bile duct proliferation, and myofibroblast transformation in experimental biliary obstruction. Male Sprague-Dawley rats were divided into two groups to receive either a single dose of gadolinium chloride (a selective Kupffer cell blocking agent) or vehicle. One day later, the gadolinium- and vehicle-treated groups were further subdivided to receive either BDL or sham operation. The rats were sacrificed on day 7 postoperatively. Serum was collected for measurement of aspartate aminotransferase, gamma-glutamyl transpeptidase, and bilirubin levels. Liver tissue was taken for evaluation of fibrosis, bile ductular cells, oval cells, and myofibroblasts. BDL resulted in elevated aspartate aminotransferase, gamma-glutamyl transpeptidase, and bilirubin in serum, and gadolinium pretreatment did not modify these effects. BDL induced marked oval cell proliferation, which was completely prevented by gadolinium pretreatment. Gadolinium did not affect the induction of bile duct expansion or myofibroblasts after BDL. We conclude that experimental biliary obstruction induces oval cell proliferation, which can be prevented by gadolinium pretreatment. This suggests that bile ductular proliferation and myofibroblast transformation are not mediated by Kupffer cells and that ductular proliferation can proceed in the absence of oval cells. Alternatively, gadolinium may directly affect oval cell proliferation after BDL.     

Qualitative and quantitative differences between bile ducts in chronic hepatitis and in primary biliary cirrhosis

AIM: Lymphocytic infiltration in the portal triads usually conceals the detection--in haematoxylin and eosin (H&E) stained sections--of bile ducts in two liver diseases: chronic hepatitis and primary biliary cirrhosis. The aim was to assess the number and the characteristics of the bile ducts in those diseases with the aid of an antibody to cytokeratin 7 (CK7). METHODS: Consecutive sections from 99 liver biopsies were stained with H&E and anti-CK7. RESULTS: In H&E sections the total number of central bile ducts in the triads was 52 in primary biliary cirrhosis (n = 37), 69 in chronic hepatitis (n = 43), and 30 in miscellaneous cases (n = 19). Using anti-CK7, the number of central bile ducts was 276 in primary biliary cirrhosis, 348 in chronic hepatitis, and 96 in miscellaneous cases. Central bile ducts with lumen were found in 93.0% of chronic hepatitis cases and in 89.5% of the miscellaneous cases, but in only 13.5% of the primary biliary cirrhosis cases. Peripheral bile ducts in groups of > or = 4/triad were found in all cases of chronic hepatitis (100%) and in 75.7% primary biliary cirrhosis cases, but only in 10.5% of the miscellaneous cases. In 21.6% of primary biliary cirrhosis cases, no bile ducts (central and/or peripheral) were present. CONCLUSIONS: Anti-CK7 detects bile ducts in the triads that are concealed by chronic inflammatory cells. Central and peripheral bile ducts in groups of > or = 4 were significantly more common in primary biliary cirrhosis and chronic hepatitis than in other liver diseases. The lack of lumen in central bile ducts, as well as the absence of central and/or peripheral bile ducts in CK7 stained liver sections, seem to be valuable additional parameters in the differential diagnosis between primary biliary cirrhosis and chronic hepatitis.     

Hedgehog-mediated mesenchymal-epithelial interactions modulate hepatic response to bile duct ligation

In bile duct-ligated (BDL) rodents, as in humans with chronic cholangiopathies, biliary obstruction triggers proliferation of bile ductular cells that are surrounded by fibrosis produced by adjacent myofibroblastic cells in the hepatic mesenchyme. The proximity of the myofibroblasts and cholangiocytes suggests that mesenchymal-epithelial crosstalk promotes the fibroproliferative response to cholestatic liver injury. Studying BDL mice, we found that bile duct obstruction induces activity of the Hedgehog (Hh) pathway, a system that regulates the viability and differentiation of various progenitors during embryogenesis. After BDL, many bile ductular cells and fibroblastic-appearing cells in the portal stroma express Hh ligands, receptor and/or target genes. Transwell cocultures of an immature cholangiocyte line that expresses the Hh receptor, Patched (Ptc), with liver myofibroblastic cells demonstrated that both cell types produced Hh ligands that enhanced each other's viability and proliferation. Further support for the concept that Hh signaling modulates the response to BDL was generated by studying PtcLacZ mice, which have an impaired ability to constrain Hh signaling due to a heterozygous deficiency of Ptc. After BDL, PtcLacZ mice upregulated fibrosis gene expression earlier than wild-type controls and manifested an unusually intense ductular reaction, more expanded fibrotic portal areas, and a greater number of lobular necrotic foci. Our findings reveal that adult livers resurrect developmental signaling systems, such as the Hh pathway, to guide remodeling of the biliary epithelia and stroma after cholestatic injury.     

Characterization of ductular hepatocytes in end-stage cirrhosis

The existence of facultative stem cells in the liver has been advocated based on observations from models of carcinogenesis in rat liver. Observations of human liver material from cases of fulminant hepatitis have shown the presence of ductular hepatocytes expressing markers of both hepatocytes and bile duct cells. We describe the morphologic features and antigenic expression of a population of ductular hepatocytes identified in a patient with end-stage cirrhosis resulting from hepatitis B infection and secondary biliary cirrhosis. By conventional light microscopy and electron microscopy, ductular hepatocytes were seen to form pseudoductules within periportal areas. Using immunohistochemical methods, these ductular hepatocytes were found to be positive for both the hepatitis B surface antigen and bile duct epithelial cytokeratin, phenotypic markers classically restricted to expression on hepatocytes and bile duct epithelium, respectively. These findings show definitively that ductular hepatocytes are intermediate cells bearing morphologic and phenotypic characteristics of both hepatocytes and bile duct epithelium. The presence of these cells indicates the existence of facultative stem cells in the adult mammalian liver.     

Morphologic features resembling transplant rejection in core biopsies of native livers from patients with Hepatitis C

Morphologic differentiation of recurrent Hepatitis C from transplant rejection is a major problem in posttransplant liver biopsies. Although biopsies of the native livers from patients with Hepatitis C are known to display bile duct damage, other morphologic features similar to those seen in rejection, such as endotheliitis, portal eosinophils, and pericentral fibrosis, are not generally acknowledged. To determine the frequency with which features morphologically similar to rejection might be present, we examined 50 cases of core-needle biopsy from the native livers of patients with Hepatitis C for the presence of the following: bile duct damage, portal eosinophils, portal or central vein endotheliitis, ductopenia, vascular obliteration, pericentral fibrosis, and pericentral mononuclear cell infiltrate. Biopsy specimens with other concurrent disease processes were excluded. The frequency of each morphologic feature was as follows: bile duct damage (30%), portal eosinophils (42%), portal endotheliitis (20%), central vein endotheliitis (0%), pericentral mononuclear cell infiltrate (14%), ductopenia (2%), atrophic-looking bile ducts (2%), vascular obliteration (0%), and pericentral fibrosis (10%). Bile duct damage and portal endotheliitis were both more common with higher grade hepatitis (Fisher exact test, P = .001). None of the morphologic parameters correlated with biopsy stage, viral genotype, or liver function tests. We conclude that features similar to those found in acute rejection are common in Hepatitis C, whereas features resembling chronic rejection are less frequent. This study provides quantitative data that supports the need to interpret these features with great caution in posttransplant liver biopsies from patients with recurrent Hepatitis C who are suspected of rejection.     

Neuroendocrine features of reactive bile ductules in cholestatic liver disease.

Various cholestatic liver diseases are accompanied by a striking increase in the number of bile ductules. This so-called ductular reaction is thought to arise both from ductular metaplasia of hepatocytes and from proliferation of pre-existing bile ductules. Previous studies have shown that these reactive bile ductules differ from their normal counterpart in enzyme and immunohistochemical make-up. Using monoclonal antibodies directed to neuroendocrine markers and immunohistochemistry, we found that reactive bile ductules in cholestatic liver disease display neuroendocrine features. In all cases of primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), extrahepatic obstruction, and acute hepatitis A, reactive bile ductules expressed the neural cell adhesion molecule (N-CAM) and reacted with monoclonal antibody A2B5. Both N-CAM and the ganglioside, recognized by A2B5, are restricted to neuroendocrine cells and tissues. In all but four of these cases, the same bile ductules expressed chromogranin-A, present in the matrix of neuroendocrine granules. Furthermore, in three cases of longstanding cholestasis, scattered periportal hepatocytes expressed chromogranin-A but not N-CAM. Other neuroendocrine markers such as neuron-specific enolase, synaptophysin, or myelin-associated glycoprotein were lacking from both bile ductules and hepatocytes. The neuroendocrine phenotype of bile ductules and hepatocytes was confirmed on electronmicroscopy, demonstrating various numbers of dense-cored, neuroendocrine granules near the peripheral cell membrane in bile ductules as well as in cells intermediate between hepatocytes and bile ductular cells. In 10 cases of normal liver tissue without ductular reaction, bile ductules lacked neuroendocrine markers except in two cases in which very weak reactivity for chromogranin-A was observed. These findings illustrate the presence of a new, neuroendocrine cell type that emerges in the liver during cholestasis. Elucidation of the significance of the neuroendocrine substance(s) produced in the dense cored granules of reactive bile ductules awaits their isolation and characterization. We can speculate that this molecule plays an autocrine or paracrine regulatory role in the process of ductular metaplasia of hepatocytes or growth of bile ductules.     

Liver histology in patients on hemodialysis with chronic hepatitis C viral infection

Hepatitis C virus (HCV) is a major cause of chronic liver disease in patients on hemodialysis. As no useful noninvasive predictors of disease activity and fibrosis have been found, liver biopsy is essential in these patients to accurately assess the severity of disease and thus the prognosis and plan management. The present study was undertaken to assess the degree of severity of necroinflammatory changes and fibrosis in liver biopsies of patients on hemodialysis with chronic HCV infection. Liver biopsies obtained from 45 patients on hemodialysis with serological evidence of chronic hepatitis C were studied. The grading of necroinflammatory activity and staging of fibrosis were histologically assessed. The majority of patients (30, i.e. 66.7%) had mild disease with mild inflammatory activity and stage 0, 1 or 2 fibrosis. There was no significant correlation between the degree of fibrosis and the age of the patients (rs = 0.015), the duration of hemodialysis (rs = 0.047) or the presence of steatosis (rs = 0.064). There was a positive correlation between the presence of bile ductular proliferation and the severity of fibrosis (rs = 0.612). It was concluded that chronic HCV infection in hemodialysis patients is relatively mild early in its course. However, serial follow-up liver biopsies are mandatory to plan appropriate intervention strategies.