Elastase and alpha 1-protease inhibitor in burn wound exudates

By degrading antithrombin III, polymorphonuclear neutrophil (PMN) elastase can become a procoagulant. Because intravascular coagulation may accompany severe burn injury, this study examined burn wound exudates for PMN elastase and its physiologic inhibitor, plasma alpha 1-protease inhibitor (alpha 1-PI), as a step in evaluating their contributions to coagulopathy in patients with burns. Each of the nine exudates examined were inhibitory for PMN elastase. Chromatographic characterization of the inhibitor indicated that it was alpha 1-PI; its elution volume for four exudates was identical to that of pure alpha 1-PI. Confirmation of the inhibitor's identity was achieved by reaction of anti-alpha 1-PI antibody with each exudate and with inhibitory chromatographic fractions of exudates with the most inhibitory activity. Inhibitor potency, determined from dose-response curves against a standard PMN elastase activity, varied twentyfold among exudates. Only one exudate had catalytic activity with the PMN elastase substrate. Although this enzyme had elastase-like properties, it appeared to differ from PMN elastase. The presence of alpha 1-PI in the wound exudate suggests that this inhibitor may act to diminish fibrin formation from the level that might otherwise have been seen if excess elastase were free to degrade antithrombin III.