Heat shock proteins 27, 60, 70, 90 alpha, and 20S proteasome in on-pump versus off-pump coronary artery bypass graft patients

Background. The secretion of heat shock protein (HSP) 27, HSP60, HSP70, HSP90 alpha, 20S proteasome, and their correlations to proinflammatory cytokine interleukin-6 is unknown in patients undergoing on-pump versus off-pump coronary artery bypass graft (CABG) operation. Methods. Forty patients were included in this explorative study (on-versus off-pump CABG, each n = 20). Serum samples were obtained before and 30 minutes, 60 minutes, and 24 hours after CABG operation. Enzyme-linked immunosorbent assay technique was utilized to determine soluble HSP27, 60, 70, and 90 alpha, 20S proteasome, and levels of interleukin-6. Results. Serum levels of HSP are increased in patients undergoing on-pump CABG operation as compared with off-pump CABG technique. These differences were highly significant for HSP27, 70, and 90 alpha at 60 minutes after initiation of cardiopulmonary bypass (all, p < 0.001). Concentrations of soluble 20S proteasome were increased 24 hours after operation in on-and off-pump CABG patients (p < 0.001) and correlated significantly with the serum content of HSP 27, 70, and 90 alpha at 60 minutes after initiation of cardiopulmonary bypass (p < 0.001). No correlation was found when comparing interleukin-6 levels with intravascular leakage of HSP and 20S proteasome after CABG operation. Conclusions. We conclude from our data that the innate immune system is activated owing to spillage of known immune modulatory and apoptosis-associated proteins after CABG operation.