Neutrophil-endothelial cells modulation in diabetic patients undergoing coronary artery bypass grafting

Diabetes mellitus is a well-known risk factor in patients undergoing coronary artery bypass grafting. Myocardial and pulmonary injury often occurs after cardiopulmonary bypass (CPB), mediated in part by neutrophil activation and adhesion to endothelial cells. The objectives of the present study are to compare the degree of neutrophil activation and neutrophil-endothelial cells adhesive interactions in diabetic patients after CPB.

Nitro-blu tetrazolium scores, CD 11b expression and neutrophil-endothelial cells adhesion were assessed in blood samples from 15 diabetic and 15 control patients who had undergone elective coronary bypass grafting. Blood samples were obtained at baseline, 30 min after beginning CPB, at the end of CPB and 60 min postoperatively. At the same sampling points as above, blood glucose levels were also checked in all patients.

Diabetes was associated with a significant basal increase in neutrophil CD1 lb expression and adhesion to endothelial cells as well as with an increased superoxide anion production. The increased adhesion of diabetic neutrophils persisted by the end of the CPB to 60 min postoperatively independently of the blood glucose levels. Antibodies directed against CD1 lb and CD18 significantly reduced the degree of neutrophil adhesion observed 60 min postoperatively.

These results indicate that diabetes mellitus is associated with an increased neutrophil-endothelial cell adhesion probably mediated by the CD1 1b/CD18 molecule; this, in turn, might be responsible for the increased risk of postoperative complications observed in diabetic patients undergoing coronary artery bypass grafting.