Pathophysiology of pancreatitis. Role of cytokines and other mediators of inflammation.

Acute pancreatitis is an inflammatory disease, which varies in severity from mild to severe. Factors determining the severity of pancreatitis are not known. It is generally believed that the earliest events in the evolution of acute pancreatitis lead to premature intra-acinar cell activation of digestive zymogens and that those enzymes, once activated cause acinar cell injury. Recent studies have suggested that the ultimate severity of resulting pancreatitis may be determined by events which occur subsequent to acinar cell injury. These include inflammatory cell recruitment and activation as well as the generation and release of cytokines and other chemical mediators of inflammation. Recently, we have undertaken studies to elucidate the role of various inflammatory agents in determining the severity of pancreatitis. Results from these ongoing studies indicate that substance P acting via neurokinin-1 (NK1) receptors, chemokines interacting with CCR1 receptors and platelet activating factor play an important pro-inflammatory role in regulating the severity of pancreatitis and associated lung injury. On the other hand, complement factor 5a (C5a) acts as an anti-inflammatory agent during the development of pancreatitis.