Pancreatic digestive enzymes are potent generators of mediators for leukocyte activation and mortality.

Abstract

Shock is associated with a dramatic rise in the level of inflammatory mediators found in plasma. The exact source of these mediators has remained uncertain. We recently examined a previously undescribed mechanism for production of inflammatory mediators in shock involving pancreatic digestive enzymes. The current in vitro study was designed to identify particular pancreatic enzymes and organs that may potentially produce inflammatory mediators. A selection of different organs from the rat (heart, liver, brain, spleen, pancreas, intestine, diaphragm, kidney, and lung) were homogenized and incubated with purified trypsin, chymotrypsin, elastase, lipase, nuclease, or amylase and the supernatant was incubated with fresh naïve leukocytes for 15 min. The level of leukocyte activation in the form of pseudopod formation and the fraction of cell death were measured. Without the addition of purified enzymes, only the homogenate of the pancreas yielded enhanced cell activation. Organs incubated with physiological concentrations of trypsin also stimulated significantly higher levels of pseudopod formation as compared with the undigested organs or enzymatic controls. Lipase and chymotrypsin were able to elicit cellular activation from selected organs such as the heart, intestine, liver and diaphragm. Undigested pancreatic homogenates were capable of producing substantial cell death, as compared with all other undigested organs. Intestinal digests with elastase, lipase, trypsin and chymotrypsin also stimulated significant cell mortality. Lipase-treated heart, liver, intestine, diaphragm, kidney, and lung stimulated cell death as well. We conclude that the intestine, as well as several other organs, may serve as a major source of inflammatory mediators during shock if exposed to digestive enzymes.