Activated pancreatic enzyme and pancreatic stone protein (PSP/reg) in bile of patients with pancreaticobiliary maljunction/ choledochal cysts.

Symptoms of pancreaticobiliary maljunction/choledochal cysts are caused by the obstruction of bile and pancreatic ducts due to protein plugs compacted in the common channel. However, the mechanism of protein plug formation remains unknown. Pancreatic stone protein (PSP) is reported to be a key protein to form protein plugs in chronic pancreatitis. Bile from 13 patients with pancreaticobiliary maljunction and bile from two normal controls were analyzed. Activity of pancreatic enzymes and the concentration of PSP were measured. The mean concentrations of PSP were 76.9+/-30.9 ng/mL in the bile-duct bile, and 76.9+/-29.8 ng/mL in the gallbladder bile. PSP was not detected in the controls (P < 0.05). In the bile-duct bile of the patients, trypsin(ogen) was detectable in nine patients, of which seven patients had activated trypsin. In the gallbladder bile, trypsin(ogen) was detectable in 12 patients, of which 9 patients had activated trypsin. Neither activated trypsin nor trypsinogen was detected in the controls. Bile in pancreaticobiliary maljunction patients contained both activated trypsin and PSP. Activated trypsin cleaves soluble PSP and creates insoluble PSP. Protein plugs in pancreaticobiliary maljunction may be formed by assembled insoluble PSP.