Circulating soluble gp130, soluble IL-6R, and IL-6 in patients undergoing cardiac surgery, with or without extracorporeal circulation

Objective: Soluble forms of interleukin-6 (IL-6) receptors are known to mod ulate biological activities of IL-6. The purpose of the study was to measur e circulating levels of IL-6, sIL-6R and sgp130 in patients undergoing coro nary artery bypass grafting with cardiopulmonary bypass (CPB group) or with out CPB (non-CPB group). Methods: The CPB group included 19 patients and th e non-CPB group 12 patients. Sera levels of IL-6, sIL-6R and sgp130 were me asured by specific ELISA at the beginning of the operation (T0, 15 min befo re skin incision) and 6 h later (T1). Results: IL-6 sera levels were respec tively 9 +/- 20 pg/ml (mean +/- SD) and 13 +/- 19 pg/ml at T0 and reached 3 40 +/- 250 pg/ml and 965 +/- 1060 pg/ml at T1 in CPB and non-CPB groups, in dicating a significant increase from T0 to T1, but no differences between t he two groups. When compared to T0 values, sgp130 levels decreased in both groups (respectively 105 +/- 37 and 115 +/- 35 ng/ml at T0 for CPB and non- CPB groups, and 72 +/- 25 and 84 +/- 29 ng/ml at T1) while we are not able to detect differences between the groups. Whatever the group or the time, s IL-6R concentrations remained unchanged. Conclusions: We showed that the in crease of IL-6 after artery bypass grafting was similar between patients op erated with CPB or without CPB. We conclude that the main inductor of IL-6 release is linked to surgical trauma rather than a reaction to CPB. Since i t is known that gp130 inhibits IL-6-biological activities, we suggest that the decrease of sgp130 sera levels could further enhance the inflammatory e ffects of IL-6 in cardiac surgery. (C) 2000 Elsevier Science B.V. All right s reserved.