Blood group antigens in the intrahepatic biliary tree. I. Distribution in the normal liver

Cox model risk score to predict survival of intrahepatic cholangiocarcinoma after ultrasound-guided ablation

PURPOSE

To explore factors associated with overall survival (OS) and progression-free survival (PFS) of intrahepatic cholangiocarcinoma (iCCA) after ultrasound-guided ablation and establish a model for survival risk evaluation.

METHODS

Data from 54 patients with 86 iCCAs between August 2008 and October 2022 were retrospectively analyzed. Cox regression were used to analyze the effects of clinical features on OS and PFS. Based on the variables screened by multivariable analysis, a model was established to predict the survival of the patients. Time-dependent receiver operating characteristic (timeROC) curve was constructed to evaluate the performance of this model. The model was further verified by bootstrap validation. The clinical usefulness of the model was evaluated by the decision curve analysis (DCA).

RESULTS

During follow up, 39 patients died and 49 patients developed recurrence. Pre-ablation CA199 level > 140 U/ml was the only independent predictor of poor PFS. Age > 70 years, early recurrence, maximal diameter of tumor size > 1.5 cm and pre-ablation CA199 level > 140 U/ml were significantly associated with poor OS. Then a model was established based on the above four variables. The areas under the timeROC curve (AUC) for 1-year, 2-year, 3-year, 5-year were 0.767, 0.854, 0.791 and 0.848, respectively. After bootstrapping for 1000 repetitions, the AUCs were similar to the initial model. DCA also demonstrated that the model had good positive net benefits.

CONCLUSION

The established model in this study could predict the survival outcomes of the patients with iCCA after thermal ablation, but further research was needed to validate the results.

The fate of donor-type ABO blood group antigen expression in liver grafts in ABO-incompatible adult living donor liver transplantation

BACKGROUND/PURPOSE

Donor-type ABO blood group antigens (dABOAgs) have been detected in ABO-incompatible adult living donor liver transplantation (ABOi ALDLT) grafts, but their fate and role in ABOi ALDLT rejection remain uncertain.

METHODS

The 0-day, <1-month, and 1-year serial liver graft biopsies from 30 ABOi ALDLT recipients were retrospectively evaluated. ABO antigen expression was quantitatively and serially measured by the mean number of positively stained vascular structures (endothelium of the capillaries, arteries, hepatic veins, and portal veins) within the portal tracts (sS).

RESULTS

The dABOAg sS counts of 0-day, <1-month, and 1-year liver graft biopsies (32.3, 20.8, and 20.6, respectively) decreased significantly (p < .001). Early rejection in the <1-month biopsy was observed in 8/30 (26.7%) recipients, four (13.3%) of whom showed antibody-mediated rejection. The sS counts tended to rebound in grafts showing early rejection, with minimal changes from the 0-day to <1-month period, but increased to pre-transplantation levels after 1 year, compared to that in grafts without early rejection (36.0, 20.4, 19.6 vs. 23.7, 21.9, 23.0, respectively; p = .040).

CONCLUSIONS

While dABOAg expression decreased after ABOi ALDLT, recipients showing early rejection showed sustained graft dABOAg expression. Therefore, dABOAg expression may be involved in the mechanism of accommodation in ABOi transplantation.

Tissue-Engineered Bile Ducts for Disease Modeling and Therapy

Recent biotechnical advances in the in vitro culture of cholangiocytes and generation of bioengineered biliary tissue have a high potential for creating biliary tissue to be used for disease modeling, drug screening, and transplantation. For the past few decades, scientists have searched for a source of cholangiocytes, focused on primary cholangiocytes or cholangiocytes derived from hepatocytes or stem cells. At the same time, the development of scaffolds for biliary tissue engineering for transplantation and modeling of cholangiopathies has been explored. In this review, we provide an overview on the current understanding of cholangiocytes sources, the effect of signaling molecules, and transcription factors on cell differentiation, along with the effects of extracellular matrix molecules and scaffolds on bioengineered biliary tissues, and their application in disease modeling and drug screening. Impact statement Over the past few decades, biliary tissue engineering has acquired significant attention, but currently a number of factors hinder this field to eventually generate bioengineered bile ducts that mimic in vivo physiology and are suitable for transplantation. In this review, we present the latest advances with respect to cell source selection, influence of growth factors and scaffolds, and functional characterization, as well as applications in cholangiopathy modeling and drug screening. This review is suited for a broad spectrum of readers, including fundamental liver researchers and clinicians with interest in the current state and application of bile duct engineering and disease modeling.

Pathobiology of biliary epithelia

Cholangiocytes are epithelial cells that line the intra- and extrahepatic biliary tree. They serve predominantly to mediate the content of luminal biliary fluid, which is controlled via numerous signaling pathways influenced by endogenous (e.g., bile acids, nucleotides, hormones, neurotransmitters) and exogenous (e.g., microbes/microbial products, drugs etc.) molecules. When injured, cholangiocytes undergo apoptosis/lysis, repair and proliferation. They also become senescent, a form of cell cycle arrest, which may prevent propagation of injury and/or malignant transformation. Senescent cholangiocytes can undergo further transformation to a senescence-associated secretory phenotype (SASP), where they begin secreting pro-inflammatory and pro-fibrotic signals that may contribute to disease initiation and progression. These and other concepts related to cholangiocyte pathobiology will be reviewed herein. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Post-transplant cholangiopathy: Classification, pathogenesis, and preventive strategies

Biliary complications are the most frequent cause of morbidity, re-transplantation, and even mortality after liver transplantation. In general, biliary leakage and anastomotic and non-anastomotic biliary strictures (NAS) can be recognized. There is no consensus on the exact definition of NAS and different names and criteria have been used in literature. We propose to use the term post-transplant cholangiopathy for the spectrum of abnormalities of large donor bile ducts, that includes NAS, but also intraductal casts and intrahepatic biloma formation, in the presence of a patent hepatic artery. Combinations of these manifestations of cholangiopathy are not infrequently found in the same liver and ischemia-reperfusion injury is generally considered the common underlying mechanism. Other factors that contribute to post-transplant cholangiopathy are biliary injury due to bile salt toxicity and immune-mediated injury. This review provides an overview of the various types of post-transplant cholangiopathy, the presumed pathogenesis, clinical implications, and preventive strategies.

Graft cholangiopathy: etiology, diagnosis, and therapeutic strategies

BACKGROUND

Graft cholangiopathy has been recognized as a significant cause of morbidity, graft loss, and even mortality in patients after orthotopic liver transplantation. The aim of this review is to analyze the etiology, pathogenesis, diagnosis and therapeutic strategies of graft cholangiopathy after liver transplantation.

DATA SOURCE

A PubMed database search was performed to identify articles relevant to liver transplantation, biliary complications and cholangiopathy.

RESULTS

Several risk factors for graft cholangiopathy after liver transplantation have been identified, including ischemia/reperfusion injury, cytomegalovirus infection, immunological injury and bile salt toxicity. A number of strategies have been attempted to prevent the development of graft cholangiopathy, but their efficacy needs to be evaluated in large clinical studies. Non-surgical approaches may offer good results in patients with extrahepatic lesions. For most patients with complex hilar and intrahepatic biliary abnormalities, however, surgical repair or re-transplantation may be required.

CONCLUSIONS

The pathogenesis of graft cholangiopathy after liver transplantation is multifactorial. In the future, more efforts should be devoted to the development of more effective preventative and therapeutic strategies against graft cholangiopathy.

Physiology of cholangiocytes

Cholangiocytes are epithelial cells that line the intra- and extrahepatic ducts of the biliary tree. The main physiologic function of cholangiocytes is modification of hepatocyte-derived bile, an intricate process regulated by hormones, peptides, nucleotides, neurotransmitters, and other molecules through intracellular signaling pathways and cascades. The mechanisms and regulation of bile modification are reviewed herein.

Living-related liver transplantation in Diego blood group disparity: a case report

To date, only limited cases of Diego blood group disparity in liver transplantation have been reported, and no cases with a long-term clinical course have been documented. Herein, we report a case of Diego blood group disparity in liver transplantation with details of long-term follow-up. The recipient was a 47-year-old woman with primary biliary cirrhosis; her 18-year-old daughter was the donor. Both recipient and donor were of blood type O according to the ABO blood group system. Preoperative serological tests showed the presence of antibodies against the Di(a) antigen only in the recipient, and not in the donor. Thus, the Diego phenotype was Di(a+) in the donor and Di(a-) in the recipient. Living-related liver transplantation was performed in July 2009. Immediate graft function was obtained, and no signs of humoral or cellular rejection were observed during the postoperative period. Further, anti-Di(a) antibodies were not detected throughout the postoperative course. The patient is alive and shows no signs of humoral rejection 34 months after liver transplantation. Liver transplantation has been performed successfully in cases of Diego blood group disparity.

Early-onset versus late-onset nonanastomotic biliary strictures post liver transplantation: risk factors reflect different pathogenesis

Nonanastomotic biliary strictures (NAS) cause significant morbidity post liver transplantation. Timing of stricture development varies considerably, but the relationship between timing of stricture onset and aetiology has not been fully elucidated. Database analysis was performed on all adult patients undergoing liver transplantation between 1st January 1990 and 31st May 2008. Diagnosis of NAS required demonstration on at least two radiological studies. Early NAS were defined as developing <1 year post transplant (minimum 1-year follow-up) and late NAS developing >1 year post transplant (minimum 10-year follow-up). Ninety-six of 397 patients developed NAS (24%); 54 were early-onset NAS (56%) and 42 late-onset NAS (44%). Primary sclerosing cholangitis (PSC) was the only risk factor for NAS overall (P = 0.001). However, when patients with PSC were excluded, older donor age was a significant risk for NAS (P = 0.003). Early-onset NAS were associated with advanced donor age (P = 0.02), high MELD score (P = 0.001) and ABO-identical grafts (P = 0.02), whereas late-onset NAS were associated with PSC (P = 0.0008), bilio-enteric anastomosis (P = 0.006) and tacrolimus (P = 0.0001). Advanced donor age is a significant risk for NAS in patients without PSC. Importantly, aetiology of NAS varies depending on time to stricture development, suggesting early-onset and late-onset NAS may have different pathogenesis.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

Heterogeneity of the intrahepatic biliary epithelium

The objectives of this review are to outline the recent findings related to the morphological heterogeneity of the biliary epithelium and the heterogeneous pathophysiological responses of different sized bile ducts to liver gastrointestinal hormones and peptides and liver injury/toxins with changes in apoptotic, proliferative and secretory activities. The knowledge of biliary function is rapidly increasing because of the recognition that biliary epithelial cells (cholangiocytes) are the targets of human cholangiopathies, which are characterized by proliferation/damage of bile ducts within a small range of sizes. The unique anatomy, morphology, innervation and vascularization of the biliary epithelium are consistent with function of cholangiocytes within different regions of the biliary tree. The in vivo models [e.g., bile duct ligation (BDL), partial hepatectomy, feeding of bile acids, carbon tetrachloride (CCl₄) or α-naphthylisothiocyanate (ANIT)] and the in vivo experimental tools [e.g., freshly isolated small and large cholangiocytes or intrahepatic bile duct units (IBDU) and primary cultures of small and large murine cholangiocytes] have allowed us to demonstrate the morphological and functional heterogeneity of the intrahepatic biliary epithelium. These models demonstrated the differential secretory activities and the heterogeneous apoptotic and proliferative responses of different sized ducts. Similar to animal models of cholangiocyte proliferation/injury restricted to specific sized ducts, in human liver diseases bile duct damage predominates specific sized bile ducts. Future studies related to the functional heterogeneity of the intrahepatic biliary epithelium may disclose new pathophysiological treatments for patients with cholangiopathies.

Intragraft expression of recipient-type ABO blood group antigens: long-term follow-up and histological features after liver transplantation

Several reports have shown detection of recipient-type ABO histo-blood group antigens (r-ABOAg) in the liver allograft, which may represent either true intragraft chimerism or other events such as cell injury. Little is known about factors that affect the timing and extent of r-ABOAg expression in the graft. We examined 65 recipients who underwent ABO nonidentical living donor liver transplantation (61 compatible, 4 incompatible). Ninety-seven postoperative specimens (71 episode biopsies, 16 protocol biopsies, and 10 explanted allografts) were available for evaluation with immunohistochemistry of ABH blood type antigens. The expression of r-ABOAg was assessed in relation to histological and clinical factors. Capillaries in the portal tracts were the primary sites of r-ABOAg expression. The percentage of specimens showing r-ABOAg expression increased with lengthening of the post-transplantation period. Only 1 (4%) of 28 specimens showed endothelium with r-ABOAg within 1 year after the procedure, but 10 (29%) of 35 did between 1 and 5 years after transplantation and 21 (62%) of 34 after more than 5 years. Proportional analysis found that chronic rejection was a significant factor (P = 0.006) for any r-ABOAg expression in the capillaries, and allograft portal fibrosis was a significant predictive factor for extensive r-ABOAg expression (seen in more than one third of the portal tracts) in the capillaries (P = 0.017). Sex mismatch, age of recipients, age of donors, graft/recipient body weight ratio, and histology other than chronic rejection and fibrosis did not correlate with the expression of r-ABOAg. In conclusion, these observations suggest that portal capillaries with r-ABOAg are the results of graft injury and repair, and some of them may be neovessels of recipient origin.

A morphometric study of the epithelium lining the rat intrahepatic biliary tree

BACKGROUND/AIMS

Morphological and functional heterogeneity of intrahepatic bile duct epithelial cells has been suggested in situ and in isolated cholangiocytes. The aim of this study was to evaluate if: (a) bile ducts, when isolated, maintain morphometric parameters similar to ducts in situ, (b) cellular organelles show heterogeneity in ducts of different size, and (c) some features permit different classes of bile ducts to be distinguished.

METHODS

Studies in situ were conducted on normal liver processed for light or electron microscopy. Data were also obtained from preparations of intrahepatic biliary tree isolated from rat liver. The whole biliary tree was cut at different levels to obtain bile ducts of different diameter. The diameter of ducts, the number of lining cells, the size and the area of individual cells, the nucleo/cytoplasmic ratio, the volume density of mitochondria, endoplasmic reticulum, Golgi complex and lysosomes have been evaluated.

RESULTS

The diameter of intrahepatic bile ducts ranged from 5 to 100 micrograms and the area of lining cells ranged from 8 to 100 micrograms2. A highly significant linear relationship existed between duct diameter and bile duct epithelial cell area (r = 0.97, p < 0.001) or number of lining cells (r = 0.96, p < 0.001). The volume density of mitochondria ranged from 7.58 +/- 2.0% of cytoplasmic volume in the smallest isolated bile ducts to 8.50 +/- 2.7% in the largest (p = NS). The volume density of lysosomes was low and was not significantly different in ducts of different size. Rough endoplasmic reticulum was inconspicuous in the smallest ducts and increased only slightly in the largest. The inverse relationship between the nucleo/cytoplasmic ratio and duct diameter was striking (r = -0.78, p < 0.001). All morphometric data were equivalent if bile ducts were evaluated in situ or in isolated fragments. Taken together, the data allowed bile ducts to be classified into 3 classes: < 10, 10-50, and > 50 micrograms in diameter.

DISCUSSION

Our data show that (a) isolated bile ducts maintain morphometric characteristics similar to the tissue in situ, (b) a low grade of morphological heterogeneity is evident for intracellular organelles in ducts of different diameter and (c) the diameter of ducts, the number of lining cells and especially the nucleo/cytoplasmic ratio may indicate the origin of fragments examined where functional studies are being considered.

Small duct cholangitis induced by N-formyl L-methionine L-leucine L-tyrosine in rats

Primary sclerosing cholangitis (PSC) frequently accompanies inflammatory bowel diseases. In an attempt to increase our understanding of the pathogenesis of PSC, we studied bile duct changes in rats with colitis which had been given N-formyl L-methionine L-leucine L-tyrosine (fMLT) rectally; fMLT is one of the chemotactic peptides produced by Escherichia coli, and is secreted into the bile by hepatocytes after it enters the portal blood. Transrectal administration of fMLT induced a marked inflammation in the portal triad and mild hepatocyte necrosis on the 4th day. The infiltrating leukocytes in the portal tract were mostly mononuclear cells, which densely infiltrated around the bile ducts. These mononuclear cells appeared to attach to bile duct epithelial cells, and they were more numerous in the smaller bile ducts. Electron microscopy revealed that lymphocytes were in direct contact with bile duct lining cells and that some epithelial cells had degenerated or collapsed. These results suggest that this E. coli-derived peptide may induce cholangitis in the small bile duct through cell-mediated mechanisms. Since these pathologic changes resemble those of the bile duct observed in the early stage of PSC, it can be concluded that bacterial chemotactic peptides may play a role in the pathogenesis of small-duct PSC.

Elevated plasma levels of a carbohydrate antigen, sialyl Lewis X, in liver diseases

A carbohydrate antigen, sialyl Lewis X (SLEX), is an inflammation-associated liver cell antigen, which is increasingly expressed as histological diagnosis progresses. A solid phase radioimmunoassay was developed to determine the plasma levels of this substance which were found to be elevated in about 70% of patients with liver disease, with no significant differences among disease groups. Although the plasma levels of SLEX were not directly correlated with the degree of hepatic SLEX expression, the abnormal values were only found in cases with hepatic SLEX expression. Cirrhotic patients with and without hepatocellular carcinoma had comparable values. Plasma levels of SLEX decreased significantly in chronic hepatitis patients successfully treated with IFN, but not in those without a favourable clinical response. Plasma SLEX was carried by some macromolecules with chromatographic and buoyant properties of mucin-type glycoproteins, and others of non-mucin type. These observations suggested that (i) the plasma levels of SLEX increase significantly but non-specifically in liver diseases, (ii) liver cells in the inflammatory lesion are probably the origin of the SLEX-active glycoproteins in the peripheral circulation, (iii) both the increased hepatic synthesis and impaired secretion of the SLEX-positive glycoproteins might be related to the tissue expression and plasma levels of SLEX, and (iv) plasma SLEX might be a useful marker to evaluate the activity of inflammatory liver disease in individual patients and to monitor their treatment.

Increased bile duct complications in liver transplantation across the ABO barrier

OBJECTIVE

This study evaluated the outcome of liver grafts from ABO incompatible donors, focusing on biliary complications, and compared the results to an ABO compatible control group. Also, the expression of donor ABH antigens in the liver graft was analyzed.

SUMMARY BACKGROUND DATA

The outcome of liver transplantation using an ABO incompatible graft is still debated. These blood group related (ABH) antigens are known to be expressed not only on the surface of the erythrocytes, but also on the epithelial cells of large bile ducts. Because the biliary epithelium of hepatic allografts may continue to express donor ABH antigens, it may be more susceptible to immunologic bile duct injury after transplantation across the ABO barrier.

METHODS

Eighteen ABO incompatible grafts were compared with 18 ABO compatible grafts in patients who were matched according to medical urgency, primary liver disease (PLD), and recipient age. After transplantation, the grafts were analyzed with cholangiography, Doppler ultrasound, or arteriography and liver histology according to protocol. Immunoperoxidase staining for ABH antigens was performed on hepatic tissue.

RESULTS

Biliary complications developed in 82% of the ABO incompatible donors, compared to 6% of the ABO matched controls. Hepatic artery thrombosis occurred in 24%. Cellular rejection was diagnosed in 65% versus only 28% in the control group. The 1-year actuarial graft survival rate was 44% versus 78% in the control group. ABH antigens of the donor were expressed on vascular endothelium and bile duct epithelial cells as long as 150 days after transplant.

CONCLUSIONS

Using ABO incompatible allografts, a high incidence of biliary and hepatic artery complications and decreased graft survival in liver transplantation were found. An immunologic injury to the bile duct epithelium and/or to vascular endothelium is suspected.

Variations in human liver fucosyltransferase activities in hepatobiliary diseases

The hyperfucosylation of a number of glycoconjugates observed in liver diseases involves the action of several specific fucosyltransferases (F.T.) notably responsible for synthesizing histo-blood group antigens. We determined the activities of alpha 3, alpha 2 and alpha 3/4 F.T. in 35 liver biopsy samples from patients with fatty liver, alcoholic or post-hepatic liver cirrhosis, primary or secondary biliary cirrhosis, acute hepatitis or a normal liver. F.T. activities were measured by transfer of GDP [14C] fucose to asialotransferrin for alpha 3 F.T., to phenyl beta-D-galactoside for alpha 2 F.T. and to 2' fucosyllactose for alpha 3/4 F.T. The diseased liver extracts showed an early increase in non-Le gene-associated alpha 3 F.T. activity (p = 0.001), which was related to the number of steatosic hepatocytes and the degree of intralobular inflammatory infiltration. Overexpression of this alpha 3 F.T. provides an explanation for the strong expression of 3-fucosyl lactosamine structures described in several hepatobiliary diseases. alpha 2 F.T. levels were significantly elevated in the two groups of liver cirrhosis and acute hepatitis (p = 0.05), but not enough to consider alpha 2 F.T. as a sensitive feature of mesenchymal cell injury. All Lewis-positive biopsies displaying biliary alterations showed increased Le gene-encoded alpha 3/4 F.T. activity (p = 0.001), which was related to the intensity of neoductular proliferation. Elevated levels of alpha 3/4 F.T. may be a very early sign of biliary regeneration.

Histochemical and cytochemical localization of blood group antigens

The oligosaccharide structures of blood group antigens are not the primary gene products; they are constructed in a stepwise manner by adding particular sugar to precursor oligosaccharides via several glycosyltransferases coded for by different blood group genes (Watkins 1966, 1978, 1980). Consequently, final profiles of antigens expressed in each cell type are influenced by many different factors such as the intrinsic composition of glycosyltransferase species which are defined by the genotype of the individuals, relative activity or amount of these enzymes (repression, derepression or induction of the enzymes), competition between enzymes with overlapping substrate specificity, the organization of the enzymes in membranes, utilizability of precursors and specific substrate sugars, and the activity level of degradating enzymes. Changes in the antigen profiles during maturation, differentiation and malignant transformation are thought to be intimately related to the variability of these factors. Although great importance attaches to histo- and cytochemical information on the distribution and levels of glycosyltransferases and messenger RNA corresponding to the relevant enzyme, detailed and precise localization of the blood group antigens and their variants is the base line for analyzing these complex factors. On the basis of individual genotype and histochemical findings about the antigen distribution and the interrelationship between cells and cellular components producing different antigenic structures (cellular and subcellular mosaicism), we can deduce precursor oligosaccharide levels as well as the status of gene activation and its primary product, glycosyltransferases. Thus, these findings are a prerequisite for further analysis at the molecular genetic level. As emphasized in this article, lectin staining or immunostaining methods with MAbs combined with glycosidase digestion procedures are powerful tools for in situ analysis of carbohydrate structures in histochemical systems. Although in some cases valuable results have been obtained by applying the technique, our knowledge concerning the distribution of complex carbohydrate structures is still far from satisfactory. Along with well defined MAbs and lectins, the key to developing our methods further is successful introduction of glycosidases, in particular, endoglycosidases since these reagents are indispensable for analyzing the inner core structures and glycoconjugate species of the blood group antigens. Application of these techniques at the ultrastructural level is an alluring possibility, even though many difficulties must be overcome. Although their functional roles have not yet been determined, a diverse array of macromolecules is known to be decorated with blood group-related antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

New monoclonal antibodies reacting with bile ducts: further insights into the pathogenesis of bile ductular proliferation in biliary diseases

We have produced a range of monoclonal antibodies which stain human intrahepatic bile ducts of different sizes. Amongst 26 monoclonal antibodies produced, five clones reacted specifically with bile ducts of different sizes, of which three have been maintained in culture and their viability following freezing and thawing confirmed. Staining patterns varied between normal adult liver tissue, normal fetal liver tissue and a variety of hepatobiliary diseases. The antibodies provide further evidence of the immunological heterogeneity of the human intrahepatic biliary tree and support the hypothesis that proliferating bile ductules are derived from periseptal hepatocytes. The preparation of the antibodies, their staining reactions in normal adult, normal fetal and a variety of liver diseases are described.

Biliary epithelial cells from the liver of patients with primary biliary cirrhosis: isolation, characterization, and short-term culture

Since biliary epithelial cells of the middle-sized interlobular bile ducts are targets for lymphocyte-mediated damage in patients with primary biliary cirrhosis (PBC), we have developed a method for isolating and maintaining these cells in short-term tissue culture. Intrahepatic biliary epithelial cells were isolated from small segments of liver removed at the time of transplantation. Cells were separated from a collagenase digest by immunomagnetic separation using Dynabeads coupled to a monoclonal antibody (HEA 125) specific for a biliary epithelial cell surface antigen. The yield was approximately 3 x 10(5) cells/g of liver. The isolated cells were characterized morphologically and ultrastructurally using light and electron microscopy, and immunocytochemically using HEA 125 and anti-cytokeratin, anti-vimentin and anti-asialoglycoprotein receptor antibodies. By these criteria cells were judged to be identical to biliary epithelial cells from normal liver. The cells could be maintained in short-term tissue culture for up to 4 weeks without loss of biliary epithelial cell markers. Availability of interlobular biliary epithelial cells will be of value in future investigations of the pathogenetic mechanisms of PBC.

Neoexpression of sialyl oligomeric Lewis X by Kupffer cells in chronic hepatitis

The expression of a carbohydrate antigen, sialyl oligomeric Lewis X (SOLex), by Kupffer cells was examined in liver biopsy specimens from patients with chronic hepatitis. The antigen was expressed by Kupffer cells from these patients but not by those from normal controls. Expression of the antigen did not correlate with the histological type of chronic hepatitis, nor with SOLex expression in liver cells, which did correlate with severity of hepatic necrosis and inflammation. Treatment of patients with interferon-alpha increased SOLex expression by Kupffer cells, but not by liver cells, which suggests different means of regulation of SOLex expression in these two cell types. SOLex and HLA class II antigens were expressed simultaneously by Kupffer cells. Expression of SOLex by Kupffer cells (HLA class II antigen-positive) and liver cells (HLA class I antigen-positive) suggests a possible autoimmune response against this carbohydrate antigen in chronic hepatitis.

Expression of blood group-related antigens in the intrahepatic biliary tree and hepatocytes in normal livers and various hepatobiliary diseases

The distribution of blood group-related antigens (A, B, H, Lea and Leb) in the intrahepatic biliary tree and hepatocytes was studied by immunoperoxidase techniques. In normal livers, large and septal bile ducts expressed A and B antigens in the cases with comparable blood groups and also expressed H antigen frequently in the cases with blood group O, A or B, and infrequently in the cases with AB. Lea and Leb were found in biliary cells at any level in secretors. In hepatobiliary diseases, A, B and H were neoexpressed in the interlobular bile ducts in addition to their expression in the large and septal bile ducts. Lea and Leb were found in almost all proliferated bile ductules and in some hepatocytes, especially those adjacent to ductules, in any of the hepatobiliary diseases, and their expression seemed parallel to the disease activity. H antigen was also neoexpressed in some hepatocytes and proliferated bile ductules. Extramural peribiliary glands expressed H, Lea, Leb and, to a lesser degree, A and B antigens in normal and pathologic conditions. This study disclosed that the normal biliary tree has a specific expression of blood group antigens at different levels and that this expression is altered in pathologic conditions. Periportal hepatocytes showed neoexpression of blood group antigens in pathologic conditions, and some of these hepatocytes may undergo ductular metaplasia.

Blood group antigens in the intrahepatic biliary tree. II. Type 1 chain N-acetyllactosamine-related carbohydrate antigens in the proliferated bile ductules

The expression of the carbohydrate antigens related to type 1 chain N-acetyllactosamine (1NAcLc) in the proliferated bile ductules was immunohistochemically examined in liver tissues of 10 cases of chronic hepatitis (CH), 9 of liver cirrhosis (LC) and 8 of alcoholic hepatitis. The ductular expression of the examined blood group antigens was essentially the same among these pathological conditions. The backbone structure, i.e., 1NAcLc (Gal beta 1----3GlcNAc beta 1----3Gal beta 1----3R), was not detected in the proliferated ductules as in the normal bile ductules. Its fucosylated structures (Le(a), Le(b) and type 1 chain H) were more strongly expressed in the proliferated ductules than in the normal ductules. Sialyl-Le(a) which was not found in the normal ductules was detected weakly but definitely in the proliferated ductules. Besides proliferated ductules, single or small numbers of epithelial cells expressing the 1NAcLc-related antigens were found intralobularly. This suggests possible migration of biliary epithelial cells into the hepatic lobules. In conclusion, within the proliferated bile ductules (a) synthesis of the 1NAcLc-related antigens is increased compared to the normal ductules, (b) the backbone structure is completely sialylated or fucosylated as in the normal ductules and (c) alpha 1----4fucosylation of sialyl-1NAcLc, i.e., sialyl-Lea, formation occurs despite its absence in the normal ductules.

Type 4 chain H expression by bile ductules and hepatocytes in cirrhosis

The monoclonal antibody MBr1 defines the blood group H determinant with beta 1----3N-acetylgalactosamine linkage (Fuc alpha 1----2Gal beta 1----3GalNAc----R) carried by type 3 or 4 backbone. The distribution of the antigen detected by this antibody was studied immunohistochemically in liver tissues. Although bile ducts with a diameter of more than about 100 microns normally expressed the MBr1-reactive antigen supranuclearly, smaller bile ducts and bile ductules did not express the antigen. In cirrhotic liver, proliferated bile ductules extensively expressed the MBr1-reactive antigen. In spite of the absence in normal liver cells, the antigen was expressed membranously in some cirrhotic liver cells. Under subcellular fractionation, MBr1 reactivity was almost exclusively recovered in the microsomal fraction. By HPTLC immunostaining, the major MBr1-reactive antigen was shown to be carried by type 4 chain H glycolipid (globo-H, Fuc alpha 1----2Gal beta 1----3GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc beta 1----1Cer). MBr1 reactive glycoprotein was not found. In conclusion, although type 4 chain H glycolipid is not expressed by normal bile ductules and liver cells, it is actively synthesized and expressed by proliferated bile ductules and some of the liver cells in cirrhosis in the absence of any neoplastic change.