Hereditary pancreatitis (HP) is a rare, early-onset genetic disorder characterized by epigastric pain and often more serious complications. We now report that an Arg-His substitution at residue 117 of the cationic trypsinogen gene is associated with the HP phenotype. This mutation was observed in all HP affected individuals and obligate carriers from five kindreds, but not in individuals who married into the families nor in 140 unrelated individuals. X-ray crystal structure analysis, molecular modelling, and protein digest data indicate that the Arg 117 residue is a trypsin-sensitive site. Cleavage at this site is probably part of a fail-safe mechanism by which trypsin, which is activated within the pancreas, may be inactivated; loss of this cleavage site would permit autodigestion resulting in pancreatitis.

During 2002 the International Association of Pancreatology developed evidenced-based guidelines on the surgical management of acute pancreatitis. There were 11 guidelines, 10 of which were recommendations grade B and one (the second) grade A. (1) Mild acute pancreatitis is not an indication for pancreatic surgery. (2) The use of prophylactic broad-spectrum antibiotics reduces infection rates in computed tomography-proven necrotizing pancreatitis but may not improve survival. (3) Fine-needle aspiration for bacteriology should be performed to differentiate between sterile and infected pancreatic necrosis in patients with sepsis syndrome. (4) Infected pancreatic necrosis in patients with clinical signs and symptoms of sepsis is an indication for intervention including surgery and radiological drainage. (5) Patients with sterile pancreatic necrosis (with negative fine-needle aspiration for bacteriology) should be managed conservatively and only undergo intervention in selected cases. (6) Early surgery within 14 days after onset of the disease is not recommended in patients with necrotizing pancreatitis unless there are specific indications. (7) Surgical and other forms of interventional management should favor an organ-preserving approach, which involves debridement or necrosectomy combined with a postoperative management concept that maximizes postoperative evacuation of retroperitoneal debris and exudate. (8) Cholecystectomy should be performed to avoid recurrence of gallstone-associated acute pancreatitis. (9) In mild gallstone-associated acute pancreatitis, cholecystectomy should be performed as soon as the patient has recovered and ideally during the same hospital admission. (10) In severe gallstone-associated acute pancreatitis, cholecystectomy should be delayed until there is sufficient resolution of the inflammatory response and clinical recovery. (11) Endoscopic sphincterotomy is an alternative to cholecystectomy in those who are not fit to undergo surgery in order to lower the risk of recurrence of gallstone-associated acute pancreatitis. There is however a theoretical risk of introducing infection into sterile pancreatic necrosis. These guidelines should now form the basis for audit studies in order to determine the quality of patient care delivery.

Cholangiocytes, the epithelial cells that line intrahepatic bile ducts, participate in bile secretion via basal and agonist-stimulated transport of solutes and water. On the basis of subtle structural differences between cholangiocytes lining small vs. large bile ducts, as well as known phenotypic variations among transporting epithelia in other organs, we demonstrated that cholangiocytes are functionally heterogeneous along the intrahepatic biliary tree of normal rats. In studies reported here, we confirm and extend the concept of functional heterogeneity of cholangiocytes by employing the bile duct-ligated (BDL) rat model of cholestasis associated with selective cholangiocyte proliferation. Using novel isolation and separatory techniques, we prepared subpopulations of pure small, medium, and large cholangiocytes from BDL rats and compared them with regard to gene expression and basal or agonist-responsive transport activities. Although transcripts for gamma-glutamyl transpeptidase and cytokeratin 19, two cholangiocyte-specific proteins, and glyceraldehyde-3-phosphate dehydrogenase, a housekeeping gene, were in all three subpopulations, genes for several proteins involved in solute transport [Cl-/HCO3- exchanger, cystic fibrosis transmembrane conductance regulator (CFTR), and secretin receptor] were expressed only in medium and large cholangiocytes. Consistent with these findings, secretin increased intracellular levels of adenosine 3',5'-cyclic monophosphate (cAMP) and 36Cl- efflux rates in medium and large cholangiocytes but not in small cholangiocytes. Also, forskolin/8-(4-chlorophenylthio)-cAMP stimulated 36Cl- efflux rates only in medium and large cholangiocytes, consistent with selective functional expression of CFTR in these subpopulations. These results support the molecular and functional heterogeneity of cholangiocytes within the intrahepatic biliary ductal system and are consistent with the notion that hormone-regulated transport of solutes after BDL occurs principally in medium and large cholangiocytes in a fashion similar to that observed in normal rat liver.

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Secretion stimulates ductular bile secretion by binding to receptors on intrahepatic bile duct epithelial cells (i.e., cholangiocytes). In the rat, this choleretic effect increases after bile duct ligation (BDL). Although cholangiocyte proliferation induced by BDL contributes to secretin-induced hypercholeresis, the mechanisms modulating these alterations in secretin-induced ductular bile secretion are obscure. Thus we studied the expression of secretin receptor mRNA (SR-mRNA) in purified liver cells from normal and BDL rats. Northern blot analysis and RNase protection assays with mRNA from purified liver cells demonstrated SR-mRNA only in cholangiocytes; moreover, SR gene expression showed a seven- to ninefold increase in individual cholangiocytes from BDL rats compared with controls. This increase in SR-mRNA expression was related to a similar increase in the rate of transcription of SR-mRNA in cholangiocytes from BDL rats. Thus our studies indicate that 1) SR-mRNA is detected in liver only in cholangiocytes; 2) BDL causes an increase in SR-mRNA in individual cholangiocytes; and 3) the increase in SR-mRNA after BDL is partly related to an increase in the rate of transcription of SR-mRNA by cholangiocytes after BDL. Our data suggest that upregulation of the SR gene may contribute to secretin-induced hypercholeresis.