Ductular Metaplasia Research Articles

A cholestatic pattern predicts major liver-related outcomes in patients with non-alcoholic fatty liver disease.

NAFLD patients usually have an increase in AST/ALT levels, but cholestasis can also be observed. We aimed to assess in subjects with NAFLD the impact of the (cholestatic) C pattern on the likelihood of developing major liver-related outcomes (MALO). Five hundred and eighty-two consecutive patients with biopsy-proven NAFLD or a clinical diagnosis of NAFLD-related compensated cirrhosis were classified as hepatocellular (H), C and mixed (M) patterns, by using the formula (ALT/ALT Upper Limit of Normal-ULN)/(ALP/ALP ULN). MALO were recorded during follow-up. An external cohort of 1281 biopsy-proven NAFLD patients was enrolled as validation set. H, M and C patterns were found in 153 (26.3%), 272 (46.7%) and 157 (27%) patients respectively. During a median follow-up of 78months, only 1 (0.6%) patient with H pattern experienced MALO, whilst 15 (5.5%) and 38 (24.2%) patients in M and C groups had MALO. At multivariate Cox regression analysis, age >55years (HR 2.55, 95% CI 1.17-5.54; p=.01), platelets <150 000/mmc (HR 0.14, 95% CI 0.06-0.32; p<.001), albumin <4g/L(HR 0.62, 95% CI 0.35-1.08; p=.09), C versus M pattern (HR 7.86, 95% CI 1.03-60.1; p=.04), C versus H pattern(HR 12.1, 95% CI 1.61-90.9; p=.01) and fibrosis F3-F4(HR 35.8, 95% CI 4.65-275.2; p<.001) were independent risk factors for MALO occurrence. C versus M pattern(HR 14.3, 95% CI 1.90-105.6; p=.008) and C versus H pattern (HR 15.6, 95% CI 2.10-115.1; p=.0068) were confirmed independently associated with MALO occurrence in the validation set. The immunohistochemical analysis found a significantly higher prevalence of moderate-high-grade ductular metaplasia combined with low-grade ductular proliferation in C pattern when compared with the biochemical H pattern. Gene expression analysis showed a lower expression of NR1H3, RXRα and VCAM1 in patients with the C pattern. The presence of a cholestatic pattern in patients with NAFLD predicts a higher risk of MALO independently from other features of liver disease.

Senescence markers in focal nodular hyperplasia of the liver: pathogenic considerations on the basis of immunohistochemical results

Focal nodular hyperplasia (FNH) is a polyclonal tumour-like hepatic lesion characterised by parenchymal nodules, connective tissue septa without interlobular bile ducts, pronounced ductular reaction and inflammation. It may represent a response to local arterial hyperperfusion and hyperoxygenation resulting in oxidative stress. We aimed at obtaining closer insight into the pathogenesis of FNH with its characteristic morphologic features. Immunohistochemistry and immunofluorescence microscopy was performed on FNH specimens using antibodies against keratins (K) 7 and 19, neural cell adhesion molecule (NCAM), lamin B1, senescence markers (CDK inhibitor 1/p21Cip1, CDK inhibitor /p16Ink4a, senescence-associated (SA) β- galactosidase activity), proliferation markers (Ki-67, proliferating-cell nuclear antigen (PCNA)), and the abnormally phosphorylated histone γ-H2AX, indicating DNA double strand breaks; moreover SA β- galactosidase activity was determined histochemically. Ductular metaplasia of hepatocytes indicated by K7 expression in the absence of K19 plays a major role in the development of ductular reaction in FNH. Moreover, the expression of senescence markers (p21Cip1, p16Ink4a, γ-H2AX, SA β-galactosidase activity) in hepatocytes and cholangiocytes suggests that stress-induced cellular senescence contributes to fibrosis and inflammation via production of components of the senescence-associated secretory phenotype. Expression of proliferation markers (Ki-67, PCNA) was not enhanced in hepatocytes and biliary cells. Senescence and ductular metaplasia of hepatocytes may thus be involved in inflammation, fibrosis and apoptosis resistance. Hence, fibrosis, inflammation and reduced apoptotic cell death, rather than proliferation (hyperplasia) may be responsible for increased tissue mass and tumour-like appearance of FNH.

A Cholestatic Pattern Predicts Liver-Related Events in Patients with Nonalcoholic Fatty Liver Disease

Background & Aims: Liver test alteration patterns can be categorized as: predominantly hepatocellular(H), with an ALT/ALP ratio>5; predominantly cholestatic pattern(C) with a ratio < 2; mixed(M), with a ratio between 2 and 5. NAFLD usually has an H pattern, but a C pattern can also be observed. We aimed to assess in subjects with NAFLD the impact of the C pattern on the likelihood of developing of liver-related events(LRE). Methods: 582 consecutive patients with biopsy-proven NAFLD or a clinical diagnosis of NAFLD-related compensated cirrhosis were classified as H, C are M patterns, by using the formula (ALT/ALT Upper Limit of Normal-ULN)/(ALP/ALP ULN). LRE were recorded during follow-up. An external cohort of 1281 biopsy-proven NAFLD patients was enrolled as validation set. Results: H, M and C patterns were found in 153(26.3%), 272(46.7%) and 157(27%) patients, respectively. During a median follow-up of 78 months, only 1(0.6%) patient with H pattern experienced LRE, while 15(5.5%) and 38(24.2%) patients in M and C group had LRE. At multivariate Cox regression analysis, age>55 years(HR2.55,95%C.I.1.17-5.54;p=0.01), platelets<150,000/mmc(HR0.14,95%C.I.0.06-0.32;p<0.001), albumin<4g/L(HR0.62,95%C.I.0.35-1.08;p=0.09), C vs M pattern(HR7.86,95%C.I.1.03-60.1;p=0.04), C vs H pattern(HR12.1,95% C.I.1.61-90.9;p=0.01) and fibrosis F3-F4(HR35.8,95%C.I.4.65-275.2;p<0.001) were independent risk factors for LRE occurrence. C vs M pattern(HR14.3,95%C.I.1.90-105.6;p=0.008) and C vs H pattern(HR15.6,95%C.I. 2.10-115.1;p=0.0068) were confirmed independently associated with LRE occurrence in the validation set. Immunohistochemical analysis found a significant higher prevalence of moderate-high grade ductular metaplasia combined with low grade ductular proliferation in C pattern when compared with biochemical H pattern. Gene expression analysis showed a lower expression of NR1H3, RXRα, VCAM1 in patients with the C pattern. Conclusions: The presence of a cholestatic pattern in patients with NAFLD predicts a higher risk of LRE independently from other features of liver disease. Funding: GS is supported by a Senior Salary Award from Fonds de la Recherche en Sante du Quebec (FRQS) (#296306). Declaration of Interest: GS has acted as speaker for Pfizer, Merck, Novonordisk, Novartis, Gilead, and AbbVie, served as an advisory board member for Merck, Gilead, Pfizer, Allergan, Novonordisk, Intercept and Novartis and has received research funding from Merck and Theratec. All others have nothing to declare. Ethical Approval: Approval was obtained by the Ethical Committee of the University Hospital “Paolo Giaccone” in Palermo.

A Monoclonal Antibody-GDNF Fusion Protein Is Not Neuroprotective and Is Associated with Proliferative Pancreatic Lesions in Parkinsonian Monkeys

Glial cell line derived neurotrophic factor (GDNF) is a neurotrophic factor that has neuroprotective effects in animal models of Parkinson’s disease (PD) and has been proposed as a PD therapy. GDNF does not cross the blood brain barrier (BBB), and requires direct intracerebral delivery to be effective. Trojan horse technology, in which GDNF is coupled to a monoclonal antibody (mAb) against the human insulin receptor (HIR), has been proposed to allow GDNF BBB transport (ArmaGen Technologies Inc.). In this study we tested the feasibility of HIRMAb-GDNF to induce neuroprotection in parkinsonian monkeys, as well as its tolerability and safety. Adult rhesus macaques were assessed throughout the study with a clinical rating scale, a computerized fine motor skills task and general health evaluations. Following baseline measurements, the animals received a unilateral intracarotid artery MPTP injection. Seven days later the animals were evaluated, matched according to disability and blindly assigned to receive twice a week iv. treatments (vehicle, 1 or 5 mg/kg HIRmAb-GDNF) for a period of three months. HIRmAb-GDNF did not improve parkinsonian motor symptoms and induced a dose-dependent hypersensitivity reaction. Quantification of dopaminergic striatal optical density and stereological nigral cell counts did not demonstrate differences between treatment groups. Focal pancreatic acinar to ductular metaplasia (ADM) was noted in four of seven animals treated with 1 mg/kg HIRmAb-GDNF; two of four with ADM also had focal pancreatic intraepithelial neoplasia 1B (PanIN-1B) lesions. Minimal to mild, focal to multifocal, nonsuppurative myocarditis was noted in all animals in the 5 mg/kg treatment group. Our results demonstrate that HIRmAb-GDNF dosing in a monkey model of PD is not an effective neuroprotective strategy and may present serious health risks that should be considered when planning future use of the IR antibody as a carrier, or of any systemic treatment of a GDNF-containing molecule.

Morphometrical and immunohistochemical study of intrahepatic bile ducts in biliary atresia

Extrahepatic biliary atresia results from a progressive destruction of the bile ducts by an inflammatory fibrosing process which leads ultimately to cirrhosis of biliary type. The etiology of the disorder remains unknown. The histological features include cholestasis, ductular proliferation, eventual loss of intrahepatic bile ducts, and ducts with primitive embryonic shape (ductal plate malformation). To examine the morphological changes of the biliary intrahepatic ducts, we aimed at investigating the cell proliferation and the diameter of the interlobular bile ducts in extrahepatic biliary atresia, and in normal liver children. Liver samples from 35 patients with biliary atresia and 10 from control normal children were used. Immunoexpression of cytokeratin 19 was evaluated and a double-staining procedure was performed with cytokeratin 8/proliferating cell nuclear antigen. The stereological measurements of the intrahepatic bile ducts diameter were evaluated by a computerized system of image analysis. The patterns of intrahepatic cholangiopathy in biliary atresia were obstructive features (42.86%), paucity of intrahepatic bile ducts (20%), ductal plate malformation (28.57%), and ductal plate malformation associated with paucity of intrahepatic bile ducts (8.57%). The average external diameter of interlobular bile ducts in biliary atresia was smaller than that of the control infant livers. Among the four patterns of biliary atresia cholangiopathies, those associated with ductopenia showed the smallest bile duct diameter. There was a negative correlation between the bile duct to portal space ratio and the age of the child at the time of Kasai portoenterostomy. Only in biliary atresia are the bile duct cells stained with proliferating cell nuclear antigen. (i) In biliary atresia, both ductular metaplasia and ductular proliferation were observed; (ii) biliary atresia associated with ductopenia showed narrowing of interlobular ducts, probably as a consequence of degeneration with atrophy and fibrosis.

Ductal plates in hepatic ductular reactions. Hypothesis and implications. I. Types of ductular reaction reconsidered

This article focuses on the observation that most hepatic ductular reactions (DRs) have ductal plate (DP)-like patterns. Considering old and recent data, it hypothesizes that in DR, dedifferentiation of hepatocytes in ductular metaplasia may lead to the de novo development of liver stem/progenitor cells (LPCs). The three recognized types of DR are reconsidered, and an additional fourth type, DR type 2B, is added. In DR type 1 whose pattern differs from DP, the pre-existing cholangiocytes multiply and adjust the ductal structure in response to micro-environmental changes induced by oedema and inflammation. This DR fails to establish new canaliculo-ductular connections. DRs types 2A, 2B and 3 represent progenitor cell-based reactions in DP configuration which establish canaliculo-ductular connections similar to DPs in embryonic and foetal liver development. DR type 2A occurs in periportal areas in chronic cholestatic and inflammatory diseases and is interpreted as a reaction of LPCs, which either pre-exist or derive from dedifferentiated hepatocytes. DR type 2B occurs in centrolobular areas and zones of parenchymal hypoxia, is induced by hypoxia and corresponds to "ductular metaplasia" like type 2A with a presumably similar cellular origin. DR type 3 relates to the well-recognized activation of LPCs that reside in the canals of Hering. All DRs in DP configuration play a role in progression of fibrosis in chronic liver diseases.

The role of bile duct reactive change in the pathogenesis of liver fibrosis due to hepatitis C

The question addressed here is: does the bile duct reactive component of hepatitis C disease progress during the progression of the disease to cirrhosis? The question is important because if the answer to the question is yes, then an important correllary question is: does the bile duct reactive component contribute to the fibrotic change which leads to cirrhosis? The first question is addressed in the present study of a series of liver biopsies taken at the four stages of liver fibrosis in patients with hepatitis C. Sixty-four patients with hepatitis who had been biopsied for staging purposes were reviewed retrospectively. The liver biopsies were routinely stained with antibodies for liver cells, bile duct cells, activated stellate cells and cells in S phase of the cell cycle and histochemical stains for collagen and basement membrane. Selective biopsies were stained for stem cells and oval cells. There was a progressive increase in metaplastic bile ductules but the increase did not reach a significant level until stages III and IV of fibrosis. There was a positive correlation between the number of ductules formed and the stage of liver fibrosis. The incidence of proliferating metaplastic ductules was low and did not change significantly during the progression of the stage of the fibrosis. Stains for oval cells and stem cells were negative. It is concluded that the answer to the question posed is: bile ductule reaction does increase during the development of cirrhosis caused by hepatitis C but the increase is due to bile ductular metaplasia, not due to proliferation.

Normalisation of High Ca 19-9 Values in Autoimmune Hepatitis after Steroidal Treatment

Carbohydrate 19-9 antigen (CA 19-9) is considered a specific marker of pancreatobiliary adenocarcinomas, but slight increase of its levels can be found in several non-malignant diseases of the liver, such as autoimmune hepatitis. We describe a case of marked CA 19-9 elevation (up to 898.0 U/ml) in a patient with autoimmune hepatitis. Laboratory and instrumental examinations excluded malignant diseases. Immunohistochemical analysis for CA 19-9 and MIB-1, performed on liver biopsy, showed reactivity in inflammatory areas, in particular in bile ductule cells and hepatocytes in ductular metaplasia, suggesting that these cells could be involved in CA 19-9 serum levels increase. After steroids, the clinical picture improved and all the laboratory parameters normalised.

Mitogenic effect of gastrin and expression of gastrin receptors in duct-like cells of rat pancreas

Background & Aims: Ductular metaplastic cells are observed during pancreas injury. Growth control by gastrin and expression of gastrin/cholecystokinin (CCK) B receptors were evaluated in these cells. Methods: Acinoductal transdifferentiation was induced in vitro by culturing of acinar cells, and ductular metaplasia was obtained in vivo by ligation of the pancreatic ducts. Mitogenic effects of gastrin I on ductal complexes in vivo and of tetragastrin, pentagastrin, and gastrin I and II, with or without the CCK-B receptor antagonist L-365,260, on duct-like cells in vitro were analyzed by 5-bromo-2'-deoxyuridine labeling. Immunocytochemistry, Western blotting, and reverse-transcription polymerase chain reaction were applied for detection of the CCK-B receptor. Results: Gastrin analogues induced a mitogenic stimulus in the duct-like cells in vitro and in ductal complexes in duct-ligated rat pancreas. Immunocytochemistry showed expression of CCK-B receptors in these models and in fetal but not normal adult exocrine pancreas. Additionally, up-regulation of CCK-B receptors during ductular metaplasia was shown by Western blotting and reverse-transcription polymerase chain reaction. Conclusions: Duct-like pancreatic epithelial cells in vitro and ductal complexes in vivo express gastrin/CCK-B receptors and proliferate in response to gastrin.GASTROENTEROLOGY 2001;121:940-949

Primary biliary cirrhosis: modalities of injury and death in biliary epithelium.

Despite the number of studies on primary biliary cirrhosis, contrasting data remain concerning modalities of cholangiocyte death. Liver biopsies obtained from 40 patients with anti mitochondrial antibody-positive primary biliary cirrhosis, at various stages of the disease, were examined, and special attention was paid to the expression of subcellular damage and evidence of apoptosis. Liver sections were stained with haematoxylin/eosin or Sirius red. Ductular mass was evaluated on sections after cytokeratin 7 staining. Apoptosis was evaluated on haematoxylin/eosin stained material or after processing for terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling assay. In 16 patients, part of the biopsy was processed for electron microscopy. Twenty histologically normal liver biopsies were used for control purposes. According to Scheuer's classification, 29 patients were classified as stage I-II, and 11 as stage III-IV. A strong staining of bile ducts was evident after immunohistochemistry for cytokeratin 7, often associated with ductular metaplasia in lobular zone 1. Cytokeratin 7-positive cells occupied 3.0+/-1.3% of liver mass as compared to 0.25+/-0.03% in controls. Ductular metaplasia accounted for 1.4+/-0.07% of all cytokeratin 7-positive cells. Regardless of staging, apoptotic bodies were seen only exceptionally in epithelial wall of bile ducts, whereas cholangiocyte damage leading to extensive lytic necrosis appeared responsible for most of the bile duct mass loss, as also confirmed by ultrastructural studies. A few terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling-positive nuclei were occasionally associated with the inflammatory infiltrate and evidence of apoptosis in hepatocytes was frequent, especially in zone 1. Regardless of staging, lytic necrosis and not apoptosis accounts for most of the bile duct loss in primary biliary cirrhosis. Furthermore, ductular metaplasia appears as a late event with highly variable pattern being observed between patients.

Role of prostanoids and nitric oxide inhibition in rats with experimental hepatic fibrosis.

Nitric oxide (NO) and prostaglandins have been proposed as vasodilator substances involved in peripheral vasodilatation characteristic of the liver cirrhosis. A link between NO and prostanoids has been suggested. The present study investigated the effect of simultaneous blockade of both, NO synthase (NOS) and cyclooxigenase (COX) in sham-operated (SO), or rats with bile-duct ligation (BDL) in the development of liver fibrosis. Animals were distributed in two groups SO (n=15) or BDL (n=15). Treatments (5 days) started three weeks after surgical procedure. Both, SO and BDL animals were treated with indomethacin (INDO) (5 mg/kg/day) alone, with NG-nitro-L-arginine-methyl-ester (NAME) (4 mg/kg/day) alone or with INDO and NAME combination at the same doses. At the end of follow-up body weight, packed cell volume, mean arterial blood pressure (MAP) and heart rate were measured. Liver tissue was processed for histological studies. In this study, BDL animals showed a decreased MAP. Treatment with L-NAME in BDL rats increased MAP. The chronic COX inhibition alone did not play an important role in the haemodynamic changes. The BDL produced a loss of hepatic structure, with ductular metaplasia that occupied the greater part of the hepatic parenchyma. Also, an important degree of fibrosis was observed. Both NO and PG synthesis inhibitors, alone or in combination, induced enhancing collagen fiber deposition in the hepatic parenchyma. These findings support the notion that the interaction between the NOS and COX pathways should be relevant in hepatic cirrhosis in which both NOS and COX are induced.

Variable Cytokeratin 7/20 Profiles in Carcinomas Involving the Liver

The coordinate expression of cytokeratin (CK) 7/20 has been useful to distinguish among carcinomas arising from different primary sites. The importance of CK typing in liver pathology has been recognized as a phenotypic marker as well. We investigated CK7/20 profiles in 25 hepatocellular carcinomas (HCCs), 27 biliary tract carcinomas (BCs), and 25 metastatic gastrointestinal adenocarcinomas (MCs). In BCs and MCs, we analyzed the relationships among tumor size, the percentage of CK20-reactive tumor cells (CK20%), and the percentage of tall columnar tumor cells (TC%). In the majority, HCCs were CK7−/20− (76%); BCs, either CK7+/20+ (41%) or CK7+/20− (56%), and MCs were CK7−/20+ (82%). In HCCs, aberrant CK7+ (20%) were associated with CK19-coexpressing pseudoglandular pattern suggesting ductular metaplasia, whereas aberrant CK20+ (4%) was associated with cellular pleomorphism accompanied by occasional cytoplasmic filamentous structures and by increased Ki-67 and p53 expression. Variable expressions according to primary sites were noted in BCs and MCs: cholangiocarcinomas (CCs) (12/19) and gallbladder carcinomas (2/3) were frequently CK20−, whereas extrahepatic bile duct carcinomas (4/5) were frequently CK20+; most MCs from colorectum (MCCs) (21/23) were CK7−, whereas all MCs from stomach (2/2) were CK7+. In particular, profiles for CCs and MCCs were differential in most cases: CK7+/20− (63%) versus CK7−/20+ (87%). In BCs, CK20% was also correlated with TC% (p = 0.002). In the majority, carcinomas involving the liver showed differential CK7/20 profiles according to their origin, suggesting their diagnostic utility. The aberrant or variable CK expressions seemed to be associated with the adoption of certain phenotypes as well.

Bile ductule formation in fetal, neonatal, and infant livers compared with extrahepatic biliary atresia

The cell of origin of intrahepatic bile ducts during fetal development remains a subject of controversy, although there has been recent evidence that they form from hepatocytes. However, the origin of neoductules and ducts in the setting of liver disease has not been extensively investigated in humans. Using anticytokeratins characteristic of hepatocytes and bile ducts, we repeated earlier studies of fetal development to compare ductule formation in normal developing and newborn livers with the ductules formed during extrahepatic biliary atresia. We utilized an antibody to proliferating cell nuclear antigen (PCNA) staining to determine which cells were in active DNA synthesis (S phase) during fetal development and liver disease progression. The results indicated that hepatocytes undergo a phenotypic switch (metaplasia) to form ductular cells during fetal development. There was no ductular cell replication in the fetal livers. In contrast, both bile ductular metaplasia and proliferation were observed in biliary atresia. Therefore, both a limiting plate phenotypic switch to ductules and replication of ductular cells play a role in the increase in the ductules seen in the progression to biliary cirrhosis. Bile ductular proliferation in biliary atresia, however, was less than that seen in hepatocytes, whereas the number of bile ductules increased and the relative proportion of hepatocytes diminished as the accompanying periductular fibrosis progressed to cirrhosis. (Hepatology 1996 Sep;24(3):568-74)

Liver hepatocyte growth factor does not always correlate with hepatocellular proliferation in human liver lesions: its specific receptor c-met does.

Increased levels of expression of hepatocyte growth factor (HGF) and its specific receptor c-met have been shown in the liver of several benign and malignant pathologies, both in experimental models and humans. We investigated by immunohistochemistry the presence of both HGF and c-met protoocogene product (c-met pp) in 20 hepatocellular carcinomas (HCCs), 5 focal nodular hyperplasias (FNHs), 4 cases of fulminant hepatitis (FH), and 1 case of regenerated liver. The c-met protooncogene product was expressed in all cases with marked overexpression in the HCCs and in ductular metaplasia. HGF was detected in the Ito cells of all cases and in neoplastic hepatocytes of 9 of 20 HCCs (45%). The proliferative index of each lesion was evaluated by means of the polyclonal antibody anti-cyclin A. When the level of expression of HGF and c-met protooncogene product with the percentage of cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A. In 11 of 20 HCCs (55%), there wa no correlation between HGF positivity and cyclin A. This seems to suggest that, independently of the levels of native liver HGF, c-met protooncogene product is the most active modulator of liver cell proliferation.

Liver hepatocyte growth factor does not always correlate with hepatocellular proliferation in human liver lesions: Its specific receptor c-met does.

Increased levels of expression of hepatocyte growth factor (HGF) and its specific receptor c-met have been shown in the liver of several benign and malignant pathologies, both in experimental models and humans. We investigated by immunohistochemistry the presence of both HGF and c-met protoocogene product (c-met pp) in 20 hepatocellular carcinomas (HCCs), 5 focal nodular hyperplasias (FNHs), 4 cases of fulminant hepatitis (FH), and 1 case of regenerated liver. The c-met protooncogene product was expressed in all cases with marked overexpression in the HCCs and in ductular metaplasia. HGF was detected in the Ito cells of all cases and in neoplastic hepatocytes of 9 of 20 HCCs (45%). The proliferative index of each lesion was evaluated by means of the polyclonal antibody anti-cyclin A. When the level of expression of HGF and c-met protooncogene product with the percentage of cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A. In 11 of 20 HCCs (55%), there wa no correlation between HGF positivity and cyclin A. This seems to suggest that, independently of the levels of native liver HGF, c-met protooncogene product is the most active modulator of liver cell proliferation. (Hepatology 1996 Jul;24(1):60-4)

Cellular distribution of androgen receptors in the liver.

In order to determine the cellular distribution of androgen receptors (AR) in normal liver and to examine whether phenotypic changes occur in a variety of non-neoplastic liver diseases, cryostat sections of explanted livers removed from 52 consecutive patients undergoing orthotopic transplantation were immunostained using an anti-androgen receptor monoclonal antibody. In histologically normal liver, AR was immunolocalised to the nuclei of hepatocytes. The proportion of positive hepatocytes varied from about 50% to greater than 90%. Staining, of variable intensity, was restricted to parenchymal cells with no evidence of zonal heterogeneity with respect to labelling intensity. In tissue from patients with biliary cirrhoses and in some cases of alcoholic cirrhosis, labelling for AR was observed in areas of ductular metaplasia but not in areas of "typical" ductular reaction (ductular proliferation). Otherwise, no consistent abnormalities in immunolabelling were seen in any of the diseased livers.

Inappropriate expression of blood group antigens in hepatic allografts

We examined the expression of blood group antigens of the ABO, Lewis and Kell antigen systems using monoclonal antibodies and immunohistochemical study on 42 liver allograft specimens from 33 patients who underwent liver transplantation between 1986 and 1991 to learn whether altered blood group antigen expression might have a bearing on the immunopathogenesis of transplant rejection. Specimens were obtained at intervals of 0 days to 3 yr after transplant; they yielded the following histological diagnoses; time zero (n = 4), acute rejection (n = 4), pure cholestasis (n = 4), biliary obstruction (n = 4), early chronic rejection (n = 4), end-stage chronic rejection (n = 15) and miscellaneous late posttransplant biopsies (n = 7). Aberrant expression of blood group antigens was observed in 5 of 15 patients with chronic rejection. Two transplants into the same group O patient showed aberrant expression of AB antigens on hepatocytes, with a canalicular pattern, in group O-transplanted livers. In all three cases in which a group O liver was transplanted into a group A recipient and histological signs of chronic rejection were present, antibody staining showed acquisition of recipient blood phenotype by the donor liver bile ducts, endothelium or both. Aberrant expression of ABO antigens was seen only in chronic rejection. In seven cases we noted canalicular staining of periportal hepatocytes with the Lewis antibodies, normally confined to ducts and ductules. This was associated with severe cholestasis in six of the seven cases and may have represented early ductular metaplasia. These changes in carbohydrate cell surface phenotype may play a role in regulation of hepatic allograft susceptibility to immune-mediated damage.

Expression of HBs- and HBc-antigen in neoductular epithelium in chronic active hepatitis B. A further support for hepato-ductular metaplasia.

Biopsy specimens (n = 61) from patients with chronic active hepatitis B and progressive fibrosis (n = 61) were studied immunohistochemically to obtain information about the histogenesis of neoductules. All the biopsies contained clusters of oval-shaped cells often arranged in the form of neoductular aggregates. These expressed cytokeratins 7 and 19 which in the normal liver are found only in bile duct and ductular epithelium but not in hepatocytes. Using monoclonal and polyclonal antibodies both hepatocytes and these oval neoductular cells were found to express HBs- and HBc-antigen in 15% and 20% of the biopsies, respectively. Taking into consideration the strong hepatocytotropism of the hepatitis B virus, the expression of HBV-antigens in neoductular cells suggest their development from HBV-infected hepatocytes. Using proliferating cell nuclear antigen (PCNA) as a marker of cell proliferation positive staining was detected only in hepatocytes but not in neoductular cells. Taken together findings further support the concept of hepatoductular metaplasia in the histogenesis of so-called "proliferating" ductules. In general the data show that hepatitis B virus infection does not prevent hepatocytes from undergoing ductular metaplasia.

Reactive human bile ductules express parathyroid hormone‐related peptide

Various cholestatic liver diseases as well as regeneration after submassive necrosis are accompanied by a striking increase in the number of bile ductules. These reactive bile ductules are thought to arise either from proliferation of pre-existing bile ductules or bile ductule-related facultative stem cells, or from ductular metaplasia of hepatocytes. Recently, we found that reactive bile ductules display neuro-endocrine features, and speculated that the substance(s), produced in the neuro-endocrine granules, might play a role in their growth and/or differentiation through an autocrine or paracrine pathway. Parathyroid hormone-related peptide has been shown to be encoded by a growth factor-regulated gene that may play a role in cell growth and differentiation. We studied the immunohistochemical expression of this peptide in human liver, including three normal biopsies, 11 cases of cholestatic liver disease, six cases of focal nodular hyperplasia and three cases of regenerating liver. In regenerating liver, primary biliary cirrhosis, primary sclerosing cholangitis and partial or intermittent obstruction, the majority of reactive ductular cells expressing neuro-endocrine markers also expressed parathyroid hormone-related peptide. In focal nodular hyperplasia, a smaller number of bile ductular cells expressed the peptide. These findings suggest that parathyroid hormone-related peptide is localized in bile ductular cells and may indicate a role for this hormone in the growth and/or differentiation of human reactive bile ductules.

Glutathione S-transferase expression in primary biliary cirrhosis supports concept of "ductular metaplasia" of hepatocytes.

Glutathione S-transferase expression in primary biliary cirrhosis supports concept of "ductular metaplasia" of hepatocytes.