Cardiopulmonary bypass increases coronary IL-8 in diabetic patients without evidence of reperfusion injury

Background. Endothelin-1 (ET-1) has been shown to be a potent agonist for m onocyte production of the neutrophil chemotactic cytokine interleukin-8 (IL -8). We have shown that diabetic patients demonstrate elevated coronary ET- 1 after coronary artery bypass grafting (CABG). We hypothesized that these same diabetic patients would manifest elevated coronary IL-8 and conjugated diene concentrations (an index of reperfusion injury). Methods. Sixteen patients [9 nondiabetics and 7 type II diabetics] underwen t nonemergent CABG. The two groups did not differ significantly in preopera tive ejection fraction, number of vessels bypassed, or cross-clamp time. Co ronary sinus samples were obtained prior to cardioplegic arrest (baseline) and at 1 and 15 min after reperfusion periods A and B (A, reperfusion of na tive coronaries + LIMA; B, reperfusion of saphenous vein grafts in addition to native coronary system + LIMA), Plasma samples were analyzed for IL-8 ( ELISA) and conjugated dienes (spectrophotometry). Results. Initially after reperfusion, IL-8 in both groups was significantly lower than precardioplegia values. In reperfusion B, only the diabetic gro up demonstrated a significant increase in IL-8 concentrations at 1 and 15 m in compared to nondiabetics. Conjugated diene levels were significantly hig her in diabetics at each time point than nondiabetics. Conclusions, This study demonstrates an early decrease in IL-8 in both grou ps, most likely related to depressed production secondary to hypothermia. T he subsequent elevation in IL-8 only in the diabetic group tvas seen withou t concomitant conjugated diene elevation. While no evidence of reperfusion injury was demonstrated in this time frame, the elevation of IL-8 in diabet ics after CABG may contribute to later infiltration and associated oxidativ e damage. (C) 1999 Academic Press.