Importance of microcirculatory disturbances in the pathogenesis of pancreatitis.

Pancreatic microvascular control is a complex physiological process which is incompletely understood. Blood flow in the pancreas is altered by a large number of endogenous and exogenous factors in the context of acute and chronic pancreatitis. The frequency of progression from acute pancreatitis to a chronic form is a controversial question. In acute pancreatitis reductions in blood flow and alterations of microvascular integrity resulting in impaired tissue oxygenation play an important part in the progression and possibly the initiation of the disease. Endothelin and nitric oxide are believed to be two of the most effective vasoactive mediators. The beneficial effect of therapeutic strategies affecting vasoactive mediators is confirmed in experimental studies. Chronic disease is associated with decreased pancreatic blood flow and histological changes in the vasculature in both patients and animal models. Further studies are needed to clarify whether ischemia in chronic pancreatitis is more important in perpetuating the disease or as primary cause of the inflammatory processes.