Extrahepatic Bile Duct Epithelium Research Articles

Glucagon- and insulin-immunopositive endocrine cells in porcine extrahepatic bile ducts and gallbladder

IntroductionPancreatic β-cells and α-cells have been found in the murine extrahepatic biliary ducts but not in the gallbladder. However, there has been no information reported in the specialized literature about the presence of glucagon- and insulin-expressing endocrine cells in porcine bile ducts and gallbladder.AimWe aimed to perform an immunohistochemical study to identify glucagon- and insulin-positive cells and their distribution in the porcine extrahepatic biliary ducts and gallbladder.MethodThe immunohistochemical method was used to detect the presence and distribution of glucagon- and insulin-positive endocrine cells in the common hepatic duct (ductus hepaticus communis), common bile duct (ductus choledochus), cystic duct (ductus cysticus), and gallbladder (vesica fellea) of male pigs. Chromogranin A was used as a typical marker for endocrine cells.ResultsThe density of chromogranin A-, glucagon- and insulin-positive cells per field was the largest in the common bile duct, followed by the common hepatic duct, cystic duct, and gallbladder. The three types of endocrine cells showed specific localization in the superficial and deep glands of the studied organs.Conclusion and clinical importanceThe distribution of glucagon- and insulin-immunopositive endocrine cells in the porcine extrahepatic biliary tract was established for the first time as a new source of these hormones. The presence of α- and β-cells in the epithelium of extrahepatic bile ducts can be applied in treatment of diabetes, taking into account the possibility to reprogram the biliary epithelium to mentioned pancreatic endocrine cell types.

Patient-Derived Organoids from Human Bile: An In Vitro Method to Study Cholangiopathies.

Cholangiopathies, including primary sclerosing cholangitis, are a group of heterogeneous diseases characterized by inflammation and fibrosis of the intrahepatic and extrahepatic bile duct epithelium. Studies, especially of primary sclerosing cholangitis, have been hampered by the difficulty in accessing the cholangiocyte, instability of in vitro culture systems, and reliance on (limited) samples from end-stage disease. Here we describe a novel method of culturing biliary cells from bile of primary sclerosing cholangitis patients undergoing endoscopic retrograde cholangiopancreatography for clinical indications. These 3D organoid cultures demonstrate a biliary phenotype, can be maintained in vitro, and biobanked for future analyses. Given the need for diagnostic and therapeutic endoscopic retrograde cholangiopancreatography throughout the disease in many primary sclerosing cholangitis patients, this method can provide longitudinal studies in individual patients, allowing for a correlation of gene expression with disease status. These organoids can react to inflammatory stimuli, resulting in the secretion of chemo/cytokines indicative of the reactive immune phenotype characteristic of primary sclerosing cholangitis. Therefore, bile-derived organoids provide a model to study the pathogenesis and pharmacotherapeutic treatment of cholangiopathies.

Resectable Cholangiocarcinoma: Reviewing the Role of Adjuvant Strategies.

Cholangiocarcinoma is a very heterogeneous and rare group of neoplasms originating from the perihilar, intra-, or extrahepatic bile duct epithelium. It represents only 3% of gastrointestinal cancers, although their incidence is increasing as its mortality increases. Surgical resection is the only potentially curative option, but unfortunately the resectability rate is low. Overall, these malignancies have got a very poor prognosis with a five-year survival rate of 5–10%. Although the five-year survival rate increases to 25–30% in the cases amenable to surgery, only 10–40% of patients present with resectable disease. Therefore, it is necessary to optimize the benefit of adjuvant strategies after surgery to increase the rate of curability. This study reviewed the role of adjuvant chemotherapy in resectable bile duct cancers.

Cell adhesion molecules P-cadherin and CD24 are markers for carcinoma and dysplasia in the biliary tract

P-cadherin (CDH3) and CD24 are cell adhesion molecules that control morphogenic processes, cell motility, and invasive growth of tumor cells. The aim of our study was to investigate P-cadherin and CD24 expression in carcinomas and dysplastic lesions of the biliary tract and to evaluate the potential diagnostic usefulness of these cell adhesion molecules. Using immunohistochemistry on tissue microarrays, we analyzed P-cadherin, CD24, and p53 expression in 117 carcinomas of the biliary tract (19 intrahepatic cholangiocarcinomas, 59 extrahepatic cholangiocarcinomas, and 39 gallbladder carcinomas) and correlated our findings with clinicopathologic parameters. We found P-cadherin positivity in 37% of intrahepatic cholangiocarcinomas, 73% of extrahepatic cholangiocarcinomas, and 64% of gallbladder carcinomas, respectively. CD24 reactivity was observed in 21% of intrahepatic cholangiocarcinomas, 58% of extrahepatic cholangiocarcinomas, and 42% of gallbladder carcinomas. Nuclear p53 expression was found in 37% of intrahepatic cholangiocarcinomas, 46% of extrahepatic cholangiocarcinomas, and 45% of gallbladder carcinomas. We also studied P-cadherin, CD24, and p53 expression in normal (n = 30), inflamed (n = 22), and dysplastic (n = 21) biliary epithelium of extrahepatic bile ducts. Dysplastic biliary epithelium was positive for P-cadherin in 91%, for CD24 in 71%, and for p53 in 24% of lesions, respectively. In contrast, normal and inflamed epithelia were negative for all 3 proteins. We conclude that P-cadherin and CD24 are expressed in carcinomas of the biliary tract with high frequency and at an early stage of carcinogenesis. Therefore, they may be useful markers for early detection and as targets for therapy of cholangiocarcinoma.

L1 Cell Adhesion Molecule Is a Novel Independent Poor Prognostic Factor of Extrahepatic Cholangiocarcinoma

Cholangiocarcinomas (CC) are associated with poor survival, but diagnostic markers and therapeutic targets have not yet been elucidated. We previously found aberrant expression of L1 cell adhesion molecule in intrahepatic CC and a role for L1 in the progression of intrahepatic CC. Here, we analyzed L1 expression in extrahepatic CC (ECC) and evaluated its prognostic significance. We examined L1 expression in tumors from 75 ECC patients by immunohistochemistry. We analyzed the correlations between L1 expression and clinicopathologic factors as well as patient survival. L1 was not expressed in normal extrahepatic bile duct epithelium but was aberrantly expressed in 42.7% of ECC tumors. High expression of L1 was detected at the invasive front of tumors and was significantly associated with perineural invasion (P < 0.01). Univariate analysis indicated that various prognostic factors such as histologic grade 3, advanced pathologic T stage and clinical stage, perineural invasion, nodal metastasis, and high expression of L1 were risk factors predicting patient survival. Multivariate analyses done by Cox's proportional hazards model showed that high expression of L1 (hazard ratio, 2.171; 95% confidence interval, 1.162-4.055; P = 0.015) and nodal metastasis (hazard ratio, 2.088; 95% confidence interval, 1.159-3.764; P = 0.014) were independent risk factors for patient death. L1 was highly expressed in 42.7% of ECC and its expression was significantly associated with perineural invasion. High expression of L1 and nodal metastasis were independent poor prognostic factors predicting overall survival in patients with ECC.

Radiologic spectrum of cholangiocarcinoma: emphasis on unusual manifestations and differential diagnoses.

Most cholangiocarcinomas are ductal adenocarcinomas that arise from both intra- and extrahepatic bile duct epithelium, and their typical growth pattern can be classified as exophytic, infiltrative, polypoid, or a combination of these. Those of unusual histologic type (eg, mucin-hypersecreting cholangiocarcinoma, squamous adenocarcinoma, biliary cystadenocarcinoma, and mucinous carcinoma) show a growth pattern different from that of the typical ones (ie, ductal). Cholangiocarcinomas frequently develop in patients with any of a variety of preexisting bile duct diseases, some of which are considered precursors of cholangiocarcinoma (eg, biliary lithiasis, clonorchiasis, recurrent pyogenic cholangitis, and primary sclerosing cholangitis). Some bulky hepatic tumors of either primary or secondary origin mimic exophytic peripheral cholangiocarcinoma. Some variants of hepatocellular carcinoma, such as sclerosing, fibrolamellar, and cholangiohepatocellular carcinoma, resemble exophytic peripheral cholangiocarcinoma, while that with intraductal growth resembles polypoid cholangiocarcinoma. Among benign bile duct diseases, tumorous conditions (eg, benign biliary tumors) may mimic polypoid cholangiocarcinoma, whereas benign stricture of various causes (eg, cholangitides, traumatic and postsurgical sequelae, chronic pancreatitis, papillary stenosis) usually mimics infiltrative cholangiocarcinoma.

Morphological observation on extrahepatic bile duct of golden hamsters fed a lithogenic diet: histochemical, ultrastructural and cell kinetic studies.

Cholelithiasis is often accompanied with disorders of the extrahepatic bile duct and pancreas. However, studies on changes of the extrahepatic bile duct in cholecystolithiasis have not shown this clearly. We therefore investigated sequential histologic changes, mucous secretion and DNA synthetic activity of the extrahepatic bile duct epithelium in cholecystolithiasis. Serial changes in the mucosal epithelial cells of the extrahepatic bile duct in golden hamsters treated with a lithogenic diet were examined by light and electron microscopy and an ultrastructural quantitative technique. In addition, epithelial cell kinetics were studied using bromodeoxyuridine (BrdU). After the 2nd week of diet, the extrahepatic bile duct showed an increase in goblet cells of the mucosal epithelium, a large number of secretory granules in the upper nuclear area of the epithelial cells and an increase in the BrdU-labeling index compared with the controls. These findings indicate that mucous secretion and cell turnover were enhanced in the mucosal epithelial cells of the extrahepatic bile duct in cholelithiasis, suggesting that the epithelial cells of the bile duct were protected and regenerating.

Rejection of murine congenic bile ducts: A model for immune-mediated bile duct disease

Immune-mediated injury of prenatal and postnatal extrahepatic bile duct epithelium has been poorly characterized. In a transplantation model of bile duct allografts, segments of the common bile duct from fetal day 18, postnatal day 7 and day 21, and adult (6-weeks) mice were grafted under the renal capsule of adult congenic mice. The progression of rejection injury in these bile duct allografts was then followed by histological evaluation at 1-week intervals. After 3 weeks there was a significant difference in the number of fetal congenic bile duct grafts that had maintained their luminal architecture compared with the more mature adult congenic grafts that had fibrosclerosed. The onset and progression of the rejection injury in the adult congenic bile duct grafts was associated with an induction of class I and class II histocompatibility antigen expression in the adult bile duct epithelium; the severity of this injury could be attenuated by treatment of the recipient mice with cyclosporin A. Thus, the fibrosclerosing lesion of extrahepatic ducts observed in this model of rejection injury is similar to the histopathology of neonatal biliary atresia or primary sclerosing cholangitis, and susceptibility to this injury is dependent on the age of the donor tissue. The immune nature of the injury and the ontogeny of expression of histocompatibility antigen in bile duct tissue indicate that the above factors may be important to the pathogenesis of these extrahepatic bile duct diseases. This experimental model may be used to test for novel factors that may modulate immune responses directed against extrahepatic bile duct epithelium.

Extrahepatic bile duct growth in mice repeatedly injected with human normal serum, IgA-deficient serum or purified secretory IgA

Another group of researchers has reported that seven intraperitoneal injections into mice of purified human serum IgA or normal human serum--but not IgA-deficient serum, mouse serum or saline--induced considerable growth of the extrahepatic bile duct epithelium. They stated that heterologous IgA was principally responsible for this effect. We have quantitated this growth by another method: enumeration of total and radiolabeled nuclei of the lumenal and glandular epithelium in transverse duct sections after tritiated thymidine injection and autoradiography. Our data show maximal incorporation between 18 and 24 hr after the last injection, with the highest labeling index in the lumenal epithelium after only three injections and before any duct enlargement. After four to seven injections, thymidine incorporation continued in juxtalumenal glands, together with massive glandular proliferation into the thickening wall and obvious inflammation. These changes were more pronounced in the liver-proximal part of the duct without affecting intrahepatic duct and gallbladder epithelia. Subcutaneous serum injections were less active. We confirm the inactivity of buffered saline, but, unlike previous authors, demonstrate strong activity in purified human milk secretory IgA and in IgA-deficient serum. We suggest that this different approach of quantitating epithelial proliferation will allow comparison of the bile duct growth effects of different, well-characterized human and animal IgA preparations.

Immunoglobulin A stimulates growth of the extrahepatic bile duct in BALB/c mice.

BALB/c mice injected with seven 0.15-ml samples of whole rabbit serum over a 2-week period developed nonneoplastic proliferation of the extrahepatic bile duct epithelium and glandular components. Sera from other animals, including bovines, humans, pigs, goats, and chickens as well as non-serum-containing secretions such as human breast milk and bile also produced this effect. Partial purification utilizing gel filtration and affinity chromatography of the active 33-65% saturated ammonium sulfate precipitate of whole serum indicated that the distribution and characteristics of this glycoprotein showed some similarities with those of IgA. Chromatographically purified human IgA was administered to BALB/c mice and was found to induce bile duct proliferation identical to that seen with whole human serum. Purified human IgG and IgM had no activity. Since IgA-containing serum from BALB/c mice was inactive, it appears that heterologous IgA functions as a specific extrahepatic bile duct growth factor (BDGF) in BALB/c mice. Murine susceptibility to the growth-stimulating effect of serum was strain specific; genetic studies utilizing crosses of susceptible (BALB/c) and resistant (C57BL/10) strains of mice revealed that the ability to respond to the infusion of BDGF is inherited in a polygenic fashion.

A light and electron microscopic study of the regenerative epithelium in the intrahepatic bile duct. Experimental study of local direct instillation of paraquat into the intrahepatic bile ducts of rats.

To date, no reliable report on the regeneration of the intrahepatic bile duct epithelium following damage to the duct has been published. In this study, a direct instillation of paraquat dichloride into the intrahepatic bile ducts of rats was carried out, and the livers were examined under light and electron microscopy. One hour after treatment, the biliary epithelia showed degeneration and necrosis, and these changes remained for a considerable period in a large majority of the ducts examined. Three weeks after instillation, low columnar epithelium consisting of hyperchromatic nuclei and eosinophilic cytoplasm was present in a medium-sized bile duct, which was collared by marked periductal fibrosis. Electron microscopically, the eosinophilic epithelium showed a marked increase in the number of rough endoplasmic reticula, ribosomes, mitochondria, and filamentous structures, suggesting an active viability of the cell. Subsequently, the eosinophilic cells were replaced by normal-appearing epithelium, not associated with the periductal fibrosis. The data suggest that an epithelial regeneration occurred in the intrahepatic duct following injury and that this activity may be similar to that of the extrahepatic bile duct epithelium.