Enhanced intracellular heat shock protein 70 expression of leukocytes and serum interleukins release: Comparison of on-pump and off-pump coronary artery surgery

Background Coronary artery bypass grafting (CABG) employing cardiopulmonary bypass (CPB; "on-pump" technique) is known to induce a systemic inflammatory response and heat-shock protein 70 kDa (HSP70) expression. The objective of the present study was to investigate the perioperative intracellular HSP70 expression of leukocytes and serum interleukin (IL) release in CABG conducted with both on-pump and off-pump techniques. Methods Thirty-seven patients referred for elective CABG were enrolled in this study. These patients were categorized into the following three groups: on-pump car- dioplegic arrest (n = 12); on-pump beating heart (n = 13); and off-pump (n = 12). Blood samples were collected at four time points during the perioperative period. Enzyme- linked immunosorbent assay (ELISA) was used to determine the serum level of IL-8, IL-10, IL-12, and HSP70. Flow cytometric analysis of intracellular HSP70 was performed in populations of lymphocytes, monocytes, and granulocytes. Results The clinical outcomes were comparable among the three groups. Elevated serum IL-8, IL-10, IL-12 were found in all three groups during the perioperative period. Serum HSP70 was elevated in all three groups and was significantly lower in the off-pump group than in the on- pump cardioplegic arrest and on-pump beating-heart groups. Heat shock protein-70 expression was found in leukocytes and showed a faster response in monocytes and granulocytes than in lymphocytes. The inflammatory response in the off-pump group was less than in either of the on-pump groups. Conclusions During the perioperative period, activation of inflammatory response was associated with enhanced expression of HSP70 within leukocytes in CABG patients.