GRANULOCYTE SUPEROXIDE ANION AND ELASTASE RELEASE DURING CARDIOPULMONARY BYPASS

Cardiopulmonary bypass (CPB) is known to induce several pathogenic res ponses in cardiovascular surgery. To explore leukocyte activation duri ng PCB, we investigated superoxide anion (O-2(-)) production by granul ocytes in 6 patients undergoing aortocoronary bypass surgery. O-2(-) p roduction was determined with chemiluminescence amplified by a cypridi na luciferin analogue. Granulocytes collected from the blood in the ar terial site of the CPB circuit were stimulated by phorbol myristate ac etate, n-formyl-methionyl-leucyl-phenylalanine, and opsonized zymosan. All the stimulators failed to disclose a significant difference betwe en the magnitude of chemiluminescence during and after CPB. However, s ignificant complement activation was detected, and the plasma level of granulocyte elastase increased gradually during and after CPB. This d iscrepancy between the unchanged O-2(-) production by stimulated granu locytes and the increase in inflammatory mediators including granulocy te elastase may be due to sequestration of activated granulocytes in e xtravascular tissues. Namely, it was highly likely that activated gran ulocytes responsible for the increased plasma elastase level were sequ estered and remained outside the blood circulation.