BACKGROUND: Acute pancreatitis is an acute inflammatory process of the pancreas that frequently involves peripancreatic tissues and at times remote organ systems. For a long time, the etiology and pathogenesis of acute pancreatitis has been intensively investigated worldwide, but the pathogenetic theories are controversial. The integrity of the pancreatic duct-acinar system might play an important role in the pathogenesis of this disease. DATA SOURCES: Web of Science and PubMed databases were searched for published studies (between January 1966 and June 2009) to identify relevant articles using the keywords 'acinar hyperstimulation', 'pathogenesis', 'acute pancreatitis', 'pancreatic duct-acinar system', and 'pancreatic duct pressure'. Most of the relevant articles were reviewed. RESULTS: From critical reading of the relevant articles, we found that the underlying mechanisms involved in the pathogenesis of acute pancreatitis are still under debate and ill-understood. On the basis of the relevant studies, we propose a hypothesis for the pathogenesis of acute pancreatitis, in which the integrity of the pancreatic duct-acinar system plays an essential role in the onset and progression of various forms of the disease. CONCLUSIONS: In our hypothesis, pancreatic duct obstruction and hyperstimulation of the exocrine pancreas are preconditions for the onset of acute pancreatitis; under the common conditions of pancreatic duct obstruction and acinar hyperstimulation, acute pancreatitis arises and develops. This may be an important common pathophysiological mechanism causing various forms of acute pancreatitis. (Hepntobiliary Pancreat Dis Int 2010; 9: 242-247)
