Pediatric Pancreaticobiliary Maljunction And The Embryonic Development Of Common Bile Duct:imaging Features And Its Molecular Mechanism

Pancreaticobiliary maljunction (PBM) is a rare anomaly, caused by the union ofpancreatic duct and bile duct outside the duodenal wall. Under this condition, the sphincterof Oddi can not regulate the outflow of bile and pancreatic juice, leading to two-wayregurgitation. PBM in Children's can occur at any age, more often in female children underthe age of10. The incidence of PBM in Asian countries is higher than other areas. Theclinical presentations of PBM varies considerably, and it often indicates as abdominal mass,jaundice, vomiting, pancreatitis and recurrent abdominal pain. Early treatment depends onaccurate and prompt imaging diagnosis. Imaging results could help in differential diagnosisby identifying the union of the pancreatic duct and bile duct. In treatment of pediatric PBM,complications, surgical treatment and cases followed up should be considersated.Cystectomy with Roux-en-Y hepaticojejunostomy was the conventional procedures inpediatric PBM patients with dilatation of the bile duct. And it has high valuable inimproving patient outcomes and reducing complications.The anatomy and embryonic development of the union of pancreatic duct and bileduct are very important to PBM and it's pathological development. To now, there is fewreport about the embryonic development of the junction of pancreatic duct and bile duct.Moreover, there is no reports on imaging methods to show embryonic development of theunion of pancreatic duct and bile duct. With the widely using of64-MSCT in clinical, it ispossible to indicate the anatomy of union of pancreatic duct and bile duc and it'ssurroundings. β-catenin is the proto-oncogene-encoded protein and it is also an importantcomponent of the Wnt/β-catenin signal pathway. C-myc and cyclin D1are the targetgenes of Wnt/β-catenin signal pathway. Wnt/β-catenin signal pathway play a importantrole in embryonic development. However, there is few reports on the embryonicdevelopment of the common bile duct, in particular whether Wnt/beta-catenin signal pathway play a role in the common bile duct development.In the present study, we collected deceased premature cadavers, and64-detectorMSCT was performed following perfusion of1ml iohexol into the duodenal papilla, andthe image was uploaded to the workstation followed by three-dimensional reconstructionto delineate the anatomical structure of the pancreaticobiliary ductal junction. The commonbile duct was collected of deceased gestational fetus, deceased premature cadavers andnewborn carcasses. Immunohistochemistry was performed to observed the expression ofbeta-catenin, C-myc and their role in the development of human embryonic common bileduct. An retrospective study was performed to analysis the value of different types ofimaging methods in diagnosing pediatric PBM. Immunohistochemistry was performed toobserved the expression of MHC,MLC20in pediatric PBM patients with dilation of bileduct.Western-blot was also performed to observed the expression of MLC20. Analysis thepossible mechanism of the morphology and function of common bile duct in pediatricPBM, which will thus provide a basis for further understanding of the pathology changeand its prevention and treatment of pediatric PBM.Part one:Assessment of the pancreatic and biliary ducts using multiplanar reformattedimages in multislice CT following perfusion with imaging agent via the ampulla of VaterObjective To delineate the structure of the pancreatic and biliary ductsin premature infants using64-detector multislice spiral computed tomography. MethodsThe duodenal papillae of15premature infant cadavers were dissected. The pancreatic andbiliary ducts were visualized using a64-detector multislice spiral computed tomography(MSCT). Imaging agent was perfused into the duodenal papillae via the ampulla of Vater.Sections of the pancreatic and biliary ducts and the sphincter of Oddi were stained withhematoxylin and eosin. Results CT scanning visualized both the pancreatic and biliaryducts as well as the common channel in nine cases (9/15;60.0%). The common bile ductwas visualized in five cases (5/15;33.3%) and the pancreatic duct in one case (1/15;6.7%).Four patterns of the pancreaticobiliary ductal junction were noticed: type-Y (11/15;73.3%),type-U (2/15;13.3%), type-V (1/15;6.7%) and type-II (1/15;6.7%). The duodenal papillawas located in the middle1/3of the duodenum in nine cases (9/15;60.0%), the lower1/3in one case (1/15;6.7%), the upper1/3in two cases (2/15;13.3%), and the distal duodenum in one case (1/15;6.7%). Conclusion MSCT and three-dimensionalreconstruction be used to visualize the junction pattern, common channel and surroundingtissue structure of the pancreatic and biliary ducts in premature infants.Part two:Expression of beta-catenin, C-myc during human common bile duct development:a possible role in common bile ducr morphogensisObjective β-catenin and c-myc play important roles in the developmentof tissues and organs. However, little is known about their expression patterns during thedevelopment of the human common bile duct. Methods Immunohistochemical methodswere used to detect β-catenin and c-myc expression in common bile duct samples from15corpses of premature infants and6spontaneously aborted fetuses. Based on the stages ofhuman fetal development, these samples were divided into four groups:12w,13–27w,28–37w and38–42w. Changes in the expression patterns of β-catenin and c-myc in thecommon bile duct during difference stages of fetal development were analyzed. ResultsAt fetal stage12w, β-catenin showed strong expression in the cell membrane accompaniedby some cytoplasmic and nuclear expression. At12–27w and28–37w, moderate β-cateninprotein levels were detected in the cell membrane, along with some cytoplasmic andnuclear expression. After37w, β-catenin showed moderate expression in the cellmembrane and some nuclear expression. C-myc showed strong expression at12w,13–27w, and28–37w, c-myc all showed strong expression. After37w, only moderatelevels of c-myc protein were detected. Conclusion These experimental results suggestthat c-myc and β-catenin may be involved in the normal development of the humancommon bile duct.Part three:MHC,MLC20protein expression in common bile duct of pediatric PBM withbile duct dilatation cases.Objective MLC20, MHC proteins are very important in contractionsmooth muscle. However,little is know about their expression in common bile duct inpediatric PBM with bile duct dilatation cases. The aim of the present study is to knowabout the expression of MLC20, MHC in common bile duct in pediatric PBM with bileduct dilatation cases. Methods Twenty-one paraffins of pediatric PBM with bile duct dilatation cases,21paraffins of neonatal corpse of common bile duct and21paraffins ofcases with extrahepatic bile duct cancer were collected. Using immunohistochemistry andimage analysis system, analysis the expression of MLC20, MHC in common bile duct inpediatric PBM cases. Using western-blot to analysis the expression of MLC20in commonbile duct in pediatric PBM cases. Results MHC expression in PBM group: MOD, MLI,MQS were:153.7989±38.0867,11.9778%±7.6718,16.0214±8.4612. In neonatalcorpse group:MOD, MLI, MQS:118.0863±26.0433,2.8000%±1.8278,3.7971±1.5688.In extrahepatric bile duct cancer group: MOD, MLI, MQS were161.2114±19.6877,2.3548%±1.6107,3.9007±2.6662. There are significant differences among the threegroups (P <0.05). Dunnet test showed: MOD, MLI and MQS of MHC in PBM group weresignificantly higher than those of neonatal corpse group(P <0.05). MLI,MQS of MHC InPBM group were higher than the extrahepatic bile duct cancer group(P <0.05). Whenanalysis MOD of MHC, there is no significant difference between PBM group andextrahepatic bile duct cancer group (P>0.05). MLC20expression in PBM group:MOD,MLI, MQS were115.6688±58.1770,21.7125%±9.6549,21.3531±6.5255. Innewborn corpse group:MOD, MLI, MQS were96.5581±9.7859,11.1812%±3.6208,10.7818±3.5323. In extrahepatic bile duct cancer group: MOD, MLI, MQS were100.8913±35.6091,14.4756%±6.1491,13.8612±6.3957. There are significantdifferences among the three groups (P <0.05). Dunnet test showed: MOD of MLC20hasno significant difference among the three group (P>0.05). MLI of MLC20in PBM groupwas higher than newborns corpse group(P <0.05), when compared Between PBM andextrahepatric bile duct cancer group, there is no significant difference between them (P>0.05). MQS of MLC20is higher than the other groups and there is significant differenceamong them(P <0.05). MLC20expression in PBM group is higher than newborns corpsegroup in western-blot, there is significant difference between the two groups(P>0.05).Conclusion With the pressure of common bile duct increasing in pediatric PBM withbile duct dilatation cases, the expression of MLC20, MHC protein are also increased insmooth muscle of common bile duct. And accordingly,the contractile function of commonbile duct also changes.Part four:Imaging and pathological features of pancreaticobiliary maljunction with bile ductdilatation in children: a retrospective case studyObjective Pancreaticobiliary maljunction (PBM) is often associatedwith congenital choledochal cyst, protein plugs and pancreatitis in children. Early diagnosis depends on imaging. Thirty-one peditaric PBM patients werecollected,comparing the image data contrast with histopathological and clinical data inorder to enhance awareness of PBM combined by bile duct dilatation, to achieve earlydiagnosis and treatment purposes. Methods A retrospective analysis was conducted in31pediatric patients with PBM. Imaging findings prior to the surgery were compared withhistology and pathology and clinical data. All the patients were follow-up and Image dataassessed by two radiologists independently. When there has disagreement, and then toconsult and Consensus. Results Dilatation of the bile duct was detected in18subjectsout of the19subjects who underwent computed tomography (CT). Ultrasonography (US)was performed in17subjects, and revealed bile duct dilatation in16cases. Bile ductdilatation was seen in16out of17subjects receiving magnetic resonancecholangiopancreatography (MRCP); one subject had pancreatitis without dilatation of thebile duct. Thirty out of31subjects successfully underwent intraoperativecholangiography(IOC); a diagnosis of PBM was established in19cases based onintraoperative cholangiography alone.Patients under2-year group presented withabdominal mass, Jaundice and clay-colored stool. But patients over2-year group werepresented with abdominal pain,fever and vomit. Twenty-six patients underwentcholedochocystectomy and Roux-en-Y hepaticojejunostomy with good outcomes. Fivecases underwent secondary choledochocystectomy and Roux-en-Y hepaticojejunostomyafter external drainage. Dense fibrous tissue, elastic fibers and smooth muscle were foundin submucosa fibers. Some of epithelium tissue Stripping and the cyst wall with chroniccholangitis. Conclusion All four imaging modalities (US, IOC, CT and MRCP) arevaluable in diagnosing pediatric PBM with bile duct dilatation. MRCP provides betterview of the pancreaticobiliary junction and should be the first choice in pediatric patientssuspected of having PBM. Epithelium tissue Stripping and the cyst wall with chroniccholangitis in pathology in pediatric PBM with bile duct dilatation.