The effect of aprotinin on interleukin-8 concentration and leukocyte adhesion molecule expression in an isolated cardiopulmonary bypass system

We examined the effect of aprotinin on the production of interleukin-8 and the expression of leukocyte adhesion molecules in an isolated cardiopulmona ry bypass circuit. Five healthy volunteers each donated 500 mi blood which was divided into equal portions (A) and (B). Portion A was treated with apr otinin 250 000 kallikrein inactivator units and added to a circuit primed w ith a further 250 000 kallikrein inactivator units. Portion B was simultane ously treated with 25 mi normal saline and added to an aprotinin-free circu it. Samples of blood were taken at donation, after addition of a drug and a t 30-min intervals throughout isolated cardiopulmonary bypass. The interleu kin-8 increase was smaller in the aprotinin group but the difference betwee n groups was not statistically significant (p>0.05). In contrast, aprotinin inhibited the cardiopulmonary bypass-induced increase in monocyte (p<0.05) and granulocyte (p<0.01) CD18 and the increase in granulocyte, but not mon ocyte, CD11b (p<0.05). Cardiopulmonary bypass had little effect on expressi on of L-selectin. These results confirm that aprotinin attenuates leukocyte activation during isolated cardiopulmonary bypass.