Release of hyaluronan and laminin into pancreatic secretions

Background: Development of fibrosis characterizes chronic pancreatitis. As it results from deposition of extracellular matrix (ECM) proteins such as h yaluronan (HA) or laminin, the release of these ECM components into blood o r pancreatic secretion may be enhanced during the course of chronic pancrea titis. Patients, Material and Methods: Using immunoassays for HA and lamini n, the concentration for these ECM components was measured in pancreatic ju ice and serum samples from 20 patients with and 20 patients without chronic pancreatitis. Pancreatic calculi of varying size and weight obtained from 13 patients with chronic pancreatitis were also examined for the content of ECM components. Tissue samples from normal pancreas and those showing chro nic pancreatitis were investigated immunocytochemically with an antibody to HA synthetase (HAS). Results: After stimulation with secretin high levels of ECM components were found in the initial washout period in chronic pancr eatitis patients as well as in controls. HA levels, however, were seen seve n times higher in patients with chronic pancreatitis (mean +/- SEM; 734 +/- 301 vs. 95 +/- 15 mu g/l; p < 0.01). Serum HA levels correlated with the d uration of chronic pancreatitis and with the levels of HA in pancreatic jui ce. HA and laminin were detected in the supernatants of pancreatic calculi (laminin 0.70 +/- 0.30 U/l; HA 275 +/- 85 mu g/l). Immunocytochemically, st rong staining for HAS was found in the duct epithelium and in centroacinar cells of chronic pancreatitis specimens. Conclusion: Demonstration of incre ased amounts of HA in pancreatic juice of chronic pancreatitis patients sti mulated with secretin suggests enhanced production of this ECM component in the chronically inflamed pancreas. The source of HA appears to be the panc reatic ductal epithelium.