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PubMed1990

[Congenital cystic dilatation of the intrahepatic bile ducts (Caroli disease)].

In two men and three women aged 64-89 years on necropsy a localized form of congenital cystic dilatation of the intrahepatic bile ducts (Caroli's disease) was found affecting the left and/or one of the segments of the right liver lobe. There was diffuse fibrosis with striking reduction of the left lobe where the dilated bile ducts were macroscopically apparent only in two subjects with concurrent occlusion of the extrahepatic bile ducts by stones and carcinoma of the head of the pancreas. Segmental dilatation of the bile ducts of the right lobe was not associated with structural changes of the hepatic tissue. On microscopic inspection the wide open or collapsed dilated bile ducts had a fibrohyaline wall of different thickness. In the smaller peripheral bile ducts there were diverticulous deformations of the lumen with persistent inflammation in the deep mucosal folds. No neuroendocrine cells or dysplastic changes were found in the mucosa and glands of the intrahepatic bile ducts.

Aged↗

PubMed1988

Expression pattern of two related cystic fibrosis-associated calcium-binding proteins in normal and abnormal tissues.

This paper reports further study of the identity and function of a protein shown to be elevated in serum from cystic fibrosis (CF) patients and clinically normal heterozygotes. Monoclonal antibodies, specifically recognizing the tentatively named cystic fibrosis antigen (CFAg), were produced. Immunoaffinity purification of CFAg from several sources revealed two components: 11 x 10(3) and 14 x 10(3) Mr protein. cDNA clones corresponding to each protein have been isolated. Data-base comparisons of the deduced amino acid sequences suggest that both genes encode related but distinct calcium-binding proteins. We propose the name calgranulin A and B, for the 11 x 10(3) and 14 x 10(3) Mr components, respectively. It is clear from the assignment of the calgranulin genes to chromosome 1 that neither is the product of the mutant CF gene, which maps to chromosome 7. We have used the monoclonal antibodies to study the tissue distribution of the two proteins in a wide-ranging immunohistological survey. Where possible the pattern of expression was confirmed by RNA blot analysis. Strong calgranulin expression in granulocytes was confirmed. In addition to myeloid cells, a restricted subset of normal stratified squamous epithelia were found to be calgranulin-positive. These included tongue, oesophagus and buccal cells, the last of which has been shown to have altered calmodulin activity in CF patients. Using indirect alkaline phosphatase staining, tissue sections of lung, pancreas and skin (normally considered sites where the CF defect is expressed) were not calgranulin-positive. However, by indirect immunofluorescence, nasal polyp sections showed weak patchy calgranulin expression in some epithelial cells, and stronger, higher frequency expression when such cells were briefly cultured.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

PubMedDate not supplied

Cystic fibrosis: spectrum of thoracic and abdominal CT findings in the adult patient.

Cystic fibrosis (CF) is an autosomal recessive disorder that is characterized by an abnormality of exocrine gland function. Adult patients represent a rapidly growing percentage of the CF population. Pulmonary changes are seen in nearly every case and are the most serious complication of CF. In advanced lung disease, bronchiectasis, emphysematous bullae, and subpleural blebs can frequently develop. Although pulmonary disease is the most common cause of death and morbidity among CF patients, there also can be involvement of other groups, particularly in adults, which show characteristic signs on CT and spiral CT. Pancreatic abnormalities are present in 85-90% of CF patients. The degree of pancreatic involvement varies, ranging form accumulations of mucus in the small ducts to totally plugged ducts, which can cause atrophy of the exocrine glands and progressive fibrosis. Pancreatic dysfunction on CT is demonstrated as fatty replacement and fibrosis of the pancreas. However, there may be scattered foci of pancreatic calcifications that can be detectable on plain radiographs. Hepatobiliary involvement follows the same pattern as pancreatic abnormalities. Bile canaliculi are plugged by mucinous material and when this plugging is of long duration, biliary cirrhosis with diffuse hepatic nodularity may develop. Such severe hepatic involvement is see in only about 2-5% of patients, although minor hepatic alterations, such as diffuse fatty changes, are fairly common. Hepatobiliary involvement is characterized by hepatic nodularity, compatible with cirrhosis, splenomegaly, and ascites. Complete obstruction of the ileum by meconium occurs in approximately 10% of newborns with CF. Intestinal findings on CT include obstruction, although this is more common in children. These CT signs should be evaluated carefully in adult patients since they may be suggestive of CF. Computed tomography offers unique information about organ involvement (other than pulmonary) that can alter diagnosis and patient management.

Adult↗

PubMed1989

Magnetic resonance imaging and computed tomography in long-term-functioning duct-occluded pancreas allotransplants.

Duct-occluded segmental-pancreas transplants develop progressive fibrotic atrophy, even though endocrine function seems to be unaffected. To determine end-stage size of the graft and to evaluate magnetic resonance imaging (MRI) and computed tomography (CT), these imaging techniques were applied in eight patients with well-functioning intraperitoneal prolamine-injected segmental-pancreas transplants for 79, 48, 35, 20, 19, 19, 18, and 10 mo. MRI was performed on a 1.5 Tesla system (Philips Gyroscan S15). T1- and T2-weighted images were acquired. CT (Siemens Somatom 2) was done before and after intravenous contrast agent. The graft was visualized in seven of eight patients with both techniques. Visualization with MRI (vs. CT) was considered excellent in 2 (vs. 1), good in 3 (vs. 6), and poor in 2 (vs. 0). The three grafts with function longer than 2 yr measured 3-4 cm in length; the remaining grafts measured 3-6 cm. Because of a marked decrease in size the transplants were no longer localized in Douglas' pouch but adjacent to or on top of the uterus or bladder, the position depending on the volume of these organs. The allografts exhibited an inhomogeneous structure with casual cystic degeneration visible with MRI due to a high signal intensity on T2-weighted images. This study suggests that shrinkage of the duct-occluded pancreatic segment due to exocrine atrophy may be terminated after approximately 2 yr. It is concluded that thereafter an overshooting fibrosis causing late endocrine graft failure may not be anticipated.

Adult↗

PubMed1992

An animal model for cystic fibrosis made by gene targeting.

Cystic fibrosis results from defects in the gene encoding a cyclic adenosine monophosphate-dependent chloride ion channel known as the cystic fibrosis transmembrane conductance regulator (CFTR). To create an animal model for cystic fibrosis, mice were generated from embryonic stem cells in which the CFTR gene was disrupted by gene targeting. Mice homozygous for the disrupted gene display many features common to young human cystic fibrosis patients, including failure to thrive, meconium ileus, alteration of mucous and serous glands, and obstruction of glandlike structures with inspissated eosinophilic material. Death resulting from intestinal obstruction usually occurs before 40 days of age.

Animals↗

PubMed1997

Infections with Pseudomonas aeruginosa in patients with cystic fibrosis.

The lung infection with Pseudomonas aeruginosa is regarded as one of the major causes of health decline in patients with cystic fibrosis (CF). The CF host response to the persistent bacterial antigen load in the endobronchiolar lumen is characterized by a pronounced humoral response, local production of cytokines, influx of neutrophils into the lung and a protease-protease inhibitor imbalance predominantly sustained by released neutrophil elastase. CF is an autosomal recessive disease, and we could demonstrate for our local patient population that the age-dependent risk to become chronically colonized with P. aeruginosa can be differentiated by the disease-causing CFTR mutation genotype. The age-specific colonisation rates were significantly lower in pancreas sufficient than in pancreas insufficient patients. P. aeruginosa is occasionally detected in throat swabs already in infancy or early childhood in most patients although there is a lapse of several years amenable to preventive measures such as vaccination until onset of persistent colonization. The epidemiology of the infection with P. aeruginosa was investigated by quantitative macrorestriction fragment pattern analysis. The distribution and frequency of clones found in CF patients match that found in other clinical and environmental aquatic habitats, but the over-representation of specific clones at a CF clinic indicates a significant impact of nosocomial transmission for the prevalence of P. aeruginosa-positive patients at a particular center. Most patients remain colonized with the initially acquired P. aeruginosa clone. According to direct sputum analysis the majority of patients is carrying a single clonal variant at a concentration of 10(7)-10(9) CFU. Co-colonization with other species or other clones is infrequent. Independent of the underlying genotype, the CF lung habitat triggers a uniform, genetically fixed conversion of bacterial phenotype. Most CFP, aeruginosa strains become non-motile, mucoid, LPS-, pyocin- and phage-deficient, secrete less virulence determinants and shift the production of cytokines evoked in neutrophils. On the other hand, other properties such as antimicrobial susceptibility or adherence to bronchial mucins remain highly variable reflecting the capacity of P. aeruginosa to adapt to ongoing changes in the CF lung habitat.

Cystic Fibrosis↗

PubMed1996

Gastrointestinal manifestations of cystic fibrosis: radiologic-pathologic correlation.

Cystic fibrosis (CF), the most common lethal autosomal recessive disease in white populations, is characterized by dysfunctional chloride ion transport across epithelial surfaces. Although recurrent pulmonary infections and pulmonary insufficiency are the principal causes of morbidity and death, gastrointestinal symptoms commonly precede the pulmonary findings and may suggest the diagnosis in infants and young children. The protean gastrointestinal manifestations of CF result primarily from abnormally viscous luminal secretions within hollow viscera and the ducts of solid organs. Bowel obstruction may be present at birth due to meconium ileus or meconium plug syndrome. Complications of meconium ileus include volvulus, small bowel atresia, perforation, and meconium peritonitis with abdominal calcifications. Older children with CF may present with bowel obstruction due to distal intestinal obstruction syndrome or colonic stricture, and tenacious intestinal residue may serve as a lead point for intussusception or cause recurrent rectal prolapse. Radiologic studies often demonstrate thickened intestinal mucosal folds in older children and uncommonly show colonic pneumatosis, peptic esophageal stricture due to gastroesophageal reflux, and duodenal ulcer. Appendicitis due to inspissated secretions is uncommon. Obstruction of ducts and ductules produces exocrine pancreatic insufficiency, pancreatitis, cholestasis, cholelithiasis, and cirrhosis with portal hypertension. On imaging studies, the pancreas is commonly small and largely replaced by fat, sometimes displays calcifications, and is rarely replaced by macrocysts. Radiologic features of hepatobiliary disease include an enlarged radiolucent liver from steatosis, gallstones, a shrunken nodular liver, splenomegaly, and portosystemic collateral vessels. With the improved survival of CF patients, an increased risk for developing gastrointestinal carcinomas has been established, many occurring as early as the 3rd decade.

Adult↗

PubMed2007

Prevalence and histopathologic characteristics of pancreatitis in cats.

Despite the high prevalence of feline pancreatic disease, no detailed description on the histopathologic nature of this disease is currently available in the literature. In this study we characterize the distribution and histopathologic changes commonly found in feline pancreases, correlate the lesions with age and gastrointestinal GI and extra-gastrointestinal disease, and compare the pancreatic lesions in cats with those in humans. The entire pancreas was removed and examined from 115 cats presented for necropsy irrespective of the cause of death. Histologic sections from left limb, right limb, and body were scored for lesions of acute (AP) and chronic pancreatitis (CP) with a scoring system based on similar systems used in human and veterinary literature. The lesions of CP in cats resemble CP in humans, with fibrosis being more prominent than inflammatory changes. Cystic degeneration gradually increased as other lesions of CP were more prominent. A distinct nodular change of zymogen depletion and acinar cell dysplasia not associated with pancreatitis was prominent in 15.6% of the pancreases. Histologically, AP consisted of neutrophilic inflammation associated with interstitial edema and necrosis of mesenteric fat. An overall prevalence of 67%, and 45% in clinically normal animals, was identified. CP was found in 69 (60.0%) pancreases, and 58 (50.4%) had CP only, with a significant correlation between age and occurrence of CP. There was a statistically significant higher prevalence of CP in the left limb in animals with gastrointestinal disease. AP was present in 18 animals (15.7%) of which 7 animals had AP only (6.1%).

Animals↗

PubMed2002

[Use of Panzytrat in the replacement therapy of exocrine pancreatic insufficiency (an analytical review)].

The development of new drug formulations of pancreatine based on the principle of microdosage with a pH-sensitive coating produced the most demonstrative clinical result--a considerable increase in duration and quality of life of patients with chronic pancreatitis and cystofibrosis, most of which are children. Clinical studies confirmed high efficiency and safety of Panzytrat in open and double blind comparative clinical studies with the participation of 4,557 patients with chronic pancreatitis, mucoviscidosis, and pancreathogenous digestion disorders. In addition to the above-mentioned symptoms, indications for application of Panzytrat also include any clinical symptoms of the pancreas relative excretory insufficiency, in particular, states after oncological diseases and surgical operations (obstruction of ducts, resection, cholecystectomy, etc.) up to a failure to adhere to a diet and overeating.

Chronic Disease↗

PubMed2003

Marked diffuse dilations of the biliary tree associated with intrahepatic calculi, biliary sludges and a mucinous cyst of the pancreatic head in a 99-year-old woman.

A 99-year-old woman was admitted to Shizuoka Shimizu Municipal Hospital because of fever and anasarca. Imaging and laboratory tests showed pneumonia, urinary tract infection, and cardiac failure. The patient died 20 days after admission. An autopsy revealed marked diffuse dilations of the biliary tree ranging from the lower common bile duct to intrahepatic bile ducts. Intrahepatic calcium bilirubinate stones and biliary sludges were recognized within the dilated bile ducts. A unilocular cyst (2 cm in diameter) was present in the pancreatic head adjacent to the lower common bile duct, and it appeared to compress the common bile duct. Histologically, the walls of the dilated biliary tree showed proliferation of peribiliary glands, fibrosis, and infiltration of lymphocytes and neutrophils (cholangitis). The lumens of the dilated biliary ducts contained neutral and acidic mucins, fibrinous materials, bacteria, neutrophils, and Aspergillus fungi, in addition to the calculi and sludges. The background liver showed atrophy (400 g). The pancreatic unilocular cyst was composed of mucous columnar cells with a few infoldings, and the pancreas also showed foci of mucinous duct hyperplasia and ectasia; the pathological diagnosis of the cyst was cystic dilations of a pancreatic duct branch (mucinous ductal ectasia or mucinous cyst). Other lesions included aspiration pneumonia, emaciation, atrophy of systemic organs, gastric leiomyoma, serous cystadenoma of the right ovary, and arteriosclerotic nephrosclerosis. The present case suggests that a mucinous cyst of the pancreas may compress the biliary tree and lead to marked diffuse dilations of the biliary tree. Alternatively, the dilations of the bile ducts may be associated with aging or may be of congenital origin. The dilated bile ducts may, in turn, give rise to bacterial and fungal cholangitis and formation of biliary sludges and intrahepatic calcium bilirubinate stones.

Aged↗

PubMed2001

Regulatory interaction between the cystic fibrosis transmembrane conductance regulator and HCO3- salvage mechanisms in model systems and the mouse pancreatic duct.

The pancreatic duct expresses cystic fibrosis transmembrane conductance regulator (CFTR) and HCO3- secretory and salvage mechanisms in the luminal membrane. Although CFTR plays a prominent role in HCO3- secretion, the role of CFTR in HCO3- salvage is not known. In the present work, we used molecular, biochemical, and functional approaches to study the regulatory interaction between CFTR and the HCO3- salvage mechanism Na+/H+ exchanger isoform 3 (NHE3) in heterologous expression systems and in the native pancreatic duct. We found that CFTR regulates NHE3 activity by both acute and chronic mechanisms. In the pancreatic duct, CFTR increases expression of NHE3 in the luminal membrane. Thus, luminal expression of NHE3 was reduced by 53% in ducts of homozygote DeltaF508 mice. Accordingly, luminal Na+-dependent and HOE694- sensitive recovery from an acid load was reduced by 60% in ducts of DeltaF508 mice. CFTR and NHE3 were co-immunoprecipitated from PS120 cells expressing both proteins and the pancreatic duct of wild type mice but not from PS120 cells lacking CFTR or the pancreas of DeltaF508 mice. The interaction between CFTR and NHE3 required the COOH-terminal PDZ binding motif of CFTR, and mutant CFTR proteins lacking the C terminus were not co-immunoprecipitated with NHE3. Furthermore, when expressed in PS120 cells, wild type CFTR, but not CFTR mutants lacking the C-terminal PDZ binding motif, augmented cAMP-dependent inhibition of NHE3 activity by 31%. These findings reveal that CFTR controls overall HCO3- homeostasis by regulating both pancreatic ductal HCO3- secretory and salvage mechanisms.

Animals↗

PubMedDate not supplied

Transplantation of the liver combined with other organs.

Patients suffering from liver failure with other end-stage organ failures may benefit from combined organ transplant procedures. Liver transplantation has been combined with other transplants to treat otherwise-intractable diseases, such as advanced cystic fibrosis, primary hyperoxaluria, and cirrhosis. Multiple organ transplantation may be indicated following the resection of certain upper abdominal malignancies. Combining bone marrow and liver transplantation shows promise in improving the immunological tolerance of the liver graft.

Adult↗

PubMed2003

Physiological modulation of CFTR activity by AMP-activated protein kinase in polarized T84 cells.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated, ATP-gated Cl(-) channel and cellular conductance regulator, but the detailed mechanisms of CFTR regulation and its regulation of other transport proteins remain obscure. We previously identified the metabolic sensor AMP-activated protein kinase (AMPK) as a novel protein interacting with CFTR and found that AMPK phosphorylated CFTR and inhibited CFTR-dependent whole cell conductances when coexpressed with CFTR in Xenopus oocytes. To address the physiological relevance of the CFTR-AMPK interaction, we have now studied polarized epithelia and have evaluated the localization of endogenous AMPK and CFTR and measured CFTR activity with modulation of AMPK activity. By immunofluorescent imaging, AMPK and CFTR share an overlapping apical distribution in several rat epithelial tissues, including nasopharynx, submandibular gland, pancreas, and ileum. CFTR-dependent short-circuit currents (I(sc)) were measured in polarized T84 cells grown on permeable supports, and several independent methods were used to modulate endogenous AMPK activity. Activation of endogenous AMPK with the cell-permeant adenosine analog 5-amino-4-imidazolecarboxamide-1-beta-d-ribofuranoside (AICAR) inhibited forskolin-stimulated CFTR-dependent I(sc) in nonpermeabilized monolayers and monolayers with nystatin permeabilization of the basolateral membrane. Raising intracellular AMP concentration in monolayers with basolateral membranes permeabilized with alpha-toxin also inhibited CFTR, an effect that was unrelated to adenosine receptors. Finally, overexpression of a kinase-dead mutant AMPK-alpha1 subunit (alpha1-K45R) enhanced forskolin-stimulated I(sc) in polarized T84 monolayers, consistent with a dominant-negative reduction in the inhibition of CFTR by endogenous AMPK. These results indicate that AMPK plays a physiological role in modulating CFTR activity in polarized epithelia and suggest a novel paradigm for the coupling of ion transport to cellular metabolism.

Adenosine Monophosphate↗

PubMed1997

Isolation and culture of bovine pancreatic duct epithelial cells.

We describe a method to isolate and culture epithelial cells from the main duct of the bovine pancreas. In primary cultures, secretin caused a dose-dependent increase in intracellular adenosine 3',5'-cyclic monophosphate (cAMP) and stimulated electrogenic transepithelial ion transport. Elevation of intracellular cAMP increased the rate coefficient for 36Cl- efflux from 0.14 +/- 0.03 to 0.47 +/- 0.12 min-1, and plasma membrane conductance, measured by the whole cell patchclamp technique, was increased from 0.7 +/- 0.1 to 6.9 +/- 0.8 nS. The cAMP-activated anion currents had properties similar to those mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Cells grown on permeable supports formed confluent monolayers with high transepithelial electrical resistance (1.004 +/- 96 omega. cm2) and generated a lumen negative transepithelial voltage difference (-2.5 +/- 0.6 mV). The short-circuit current (Isc) was increased by forskolin or secretin and was inhibited 87 +/- 4% by addition of ouabain (100 microM) to the basolateral bathing solution. Replacement of bathing solution Cl- by cyclamate reduced the forskolin-induced steady-state increase in Isc from 5.3 +/- 0.5 to 0.2 +/- 0.2 microA/cm2, suggesting that the stimulated current is due to anion secretion. The results of these studies demonstrate that large numbers of pancreatic ductal cells can be isolated and grown in primary cell culture. The monolayers express differentiated functions and will be useful for studies of acute and chronic regulation of ion transport in pancreatic duct epithelial cells.

Animals↗

PubMed1987

C. L. Oakley lecture (1987). The pathogenesis of beta cell destruction in type I (insulin-dependent) diabetes mellitus.

In a study of pancreases from 75 patients who died at presentation of Type I diabetes there was selective destruction of beta cells associated with islet inflammation (insulitis). According to a recent hypothesis, aberrant expression of Class II major histocompatibility complex (MHC) products on a target cell may allow presentation of organ specific surface antigen(s) to potentially autoreactive T helper lymphocytes and thus lead to autoimmunity. Aberrant expression of Class II MHC was demonstrated immunohistochemically on beta cells in 21 out of 23 patients with recent onset diabetes. No such expression was seen on the other pancreatic endocrine cells. Ninety-four per cent of insulin-containing islets in these patients had marked hyperexpressions of Class I MHC affecting all endocrine cells in these islets. Insulin deficient islets were not thus affected. Both these abnormalities of MHC expression appeared to precede insulitis within a given islet and appeared to be unique to Type I diabetes, being absent in pancreases of patients with Type II diabetes, chronic pancreatitis, cystic fibrosis, graft-versus-host disease and Coxsackie B viral pancreatitis. The development of autoimmunity to beta cells in Type I diabetes may be a 'multistep' process in which abnormalities of MHC expression are crucial events.

Adult↗

PubMed2005

Common bile duct obstruction due to a duodenal gastrinoma in a dog.

In dogs gastrinomas are rare endocrine neoplasms that have always been reported to arise from the pancreas. We report here what we believe to be the first case of a duodenal gastrinoma in a dog. A nine-year-old, male, Pekinese dog was presented with a three-day history of anorexia, vomiting and mucous diarrhoea. Clinical examination and laboratory findings suggested the presence of a severe hepatobiliary disorder. Abdominal ultrasonography showed a diffuse increase in echogenicity of the liver, with severe gallbladder dilation and marked dilation of the cystic duct, common bile duct and extrahepatic bile ducts. Based on these findings, an extrahepatic biliary tract obstruction (EBTO) of unknown cause was suspected. At laparotomy, the gallbladder and the extrahepatic bile ducts appeared severely dilated. The gallbladder was tense and could not be compressed suggesting an outflow obstruction. The duodenum at the level of the common duct orifice appeared slightly thickened and severely hardened for a length of 1 cm. Biopsies from the duodenum and liver were obtained and a cholecystoduodenostomy was performed. The duodenal biopsy revealed severe fibrosis of the submucosa and a infiltrate of small pockets and cords of round to polygonal cells with granular cytoplasm. Based on this appearance the differential diagnoses included neuroendocrine tumours and poorly differentiated carcinoma. Despite surgery and supportive therapy the dog continued to be anorexic and to vomit 3-6 times daily. After euthanasia and necropsy, histopathology showed the presence of a neuroendocrine neoplasia involving the duodenal wall with focal invasion of the adjacent pancreas and small liver metastases. On immunohistochemistry, the cytoplasm of approximately 90% of neoplastic cells intensely expressed neuron specific enolase and gastrin. These findings were consistent with a diagnosis of gastrinoma.

Animals↗

PubMed2000

In vitro validation of duct differentiation in developing embryonic mouse pancreas.

BACKGROUND: Early embryonic pancreatic epithelia have the capacity for either endocrine or exocrine lineage commitment. Recent studies demonstrated the pluripotential nature of these undifferentiated cells. Isolated pancreatic epithelia grown under the renal capsule formed primarily islets. However, when these same epithelia were grown in a basement-membrane-rich gel (Matrigel) they formed mostly ducts. Currently, there is no model for in vitro pancreatic duct formation and therefore, the mechanism of duct morphogenesis has never been described. The purpose of this study was to provide such a model by characterizing the expression of two duct markers, carbonic anhydrase II (CAII) and the cystic fibrosis transmembrane conductance regulator (CFTR), in isolated undifferentiated pancreatic epithelia grown in vitro. MATERIALS AND METHODS: We microdissected embryonic pancreases at Embryonic Days (E)9.5-11.5 and performed RT-PCR for CAII and CFTR on E9.5 whole pancreases, E10. 5 and E11.5 epithelia, as well as E11.5 epithelia grown for 7 days in Matrigel. Next we performed in situ hybridization for CAII and CFTR and immunohistochemistry for CAII on E11.5 epithelia grown for 7 days in Matrigel. RESULTS: Early, undifferentiated embryonic pancreatic epithelium does not express CAII and CFTR by RT-PCR. When E11.5 epithelia were grown for 7 days in Matrigel, however, gene expression for both markers is upregulated as ducts form. Furthermore, CAII was seen by IHC and both CAII and CFTR were seen by in situ hybridization in the ducts after 7 days in Matrigel. CONCLUSIONS: These data validate our in vitro system as a model for studying the mechanism of normal pancreatic duct differentiation and may potentially help us to understand the faulty mechanism involved in pancreatic ductal carcinogenesis.

Animals↗

PubMed2002

The cystic fibrosis transmembrane conductance regulator interacts with and regulates the activity of the HCO3- salvage transporter human Na+-HCO3- cotransport isoform 3.

Cystic fibrosis transmembrane conductance regulator (CFTR) regulates both HCO(3)(-) secretion and HCO(3)(-) salvage in secretory epithelia. At least two luminal transporters mediate HCO(3)(-) salvage, the Na(+)/H(+) exchanger (NHE3) and the Na(+)-HCO(3)(-) cotransport (NBC3). In a previous work, we show that CFTR interacts with NHE3 to regulate its activity (Ahn, W., Kim, K. W., Lee, J. A., Kim, J. Y., Choi, J. Y., Moe, O. M., Milgram, S. L., Muallem, S., and Lee, M. G. (2001) J. Biol. Chem. 276, 17236-17243). In this work, we report that transient or stable expression of human NBC3 (hNBC3) in HEK cells resulted in a Na(+)-dependent, DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid)- and 5-ethylisopropylamiloride-insensitive HCO(3)(-) transport. Stimulation of CFTR with forskolin markedly inhibited NBC3 activity. This inhibition was prevented by the inhibition of protein kinase A. NBC3 and CFTR could be reciprocally coimmunoprecipitated from transfected HEK cells and from the native pancreas and submandibular and parotid glands. Precipitation of NBC3 or CFTR from transfected HEK293 cells and from the pancreas and submandibular gland also coimmunoprecipitated EBP50. Glutathione S-transferase-EBP50 pulled down CFTR and hNBC3 from cell lysates when expressed individually and as a complex when expressed together. Notably, the deletion of the C-terminal PDZ binding motifs of CFTR or hNBC3 prevented coimmunoprecipitation of the proteins and inhibition of hNBC3 activity by CFTR. We conclude that CFTR and NBC3 reside in the same HCO(3)(-)-transporting complex with the aid of PDZ domain-containing scaffolds, and this interaction is essential for regulation of NBC3 activity by CFTR. Furthermore, these findings add additional evidence for the suggestion that CFTR regulates the overall trans-cellular HCO(3)(-) transport by regulating the activity of all luminal HCO(3)(-) secretion and salvage mechanisms of secretory epithelial cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗