A single nucleotide polymorphism of macrophage migration inhibitory factor is related to inflammatory response in coronary bypass surgery using cardiopulmonary bypass.

OBJECTIVE Cardiac surgery causes induction and release of inflammatory mediators that may be regulated by genetic background. Macrophage migration inhibitory factor (MIF) is a proinflammatory mediator that is known to be up-regulated in patients undergoing cardiac operations. Here we analyzed genotype distribution and allele frequency of the MIF-173*G/C single nucleotide polymorphism (SNP) and MIF plasma levels in patients undergoing surgical revascularization with (on-pump, n=45) and without (off-pump, n=34) cardiopulmonary bypass (CPB). METHODS Genotyping was performed using a real-time PCR-based system with a hybridization probe system specific for the MIF-173*G/C SNP. In on-pump patients, blood samples were drawn before start of CPB, after termination of CPB and 12h postoperatively. In off-pump patients, blood samples were collected before stabilizer placement, after removal of the stabilizer and 12h postoperatively. MIF levels were measured using ELISA technique. RESULTS Genotype distribution and allele frequencies were comparable between on-pump and off-pump patients. When comparing patients according to MIF genotype, a significant increase of MIF plasma levels after completed coronary bypass grafting using CPB was found in patients heterozygous for the MIF-173*G/C SNP (p<0.05). Moreover, on-pump patients showed significantly decreased MIF plasma levels after 12h postoperatively (p<0.05). In off-pump patients, MIF plasma levels were not significantly different over the time-course and were independent of the genotype. CONCLUSIONS Patients carrying the C-allele showed significantly increased levels of the proinflammatory cytokine MIF compared to G/G homozygous when revascularization was carried out using CPB. The G/C genotype may be associated with a severe inflammatory reaction and therefore preoperative screening could be beneficial for patients undergoing cardiac surgery using CPB.