Abstract
Interleukin-6 (IL-6) can cause pro- and anti-inflammatory effects via different signaling pathways. This prospective study investigated the perioperative kinetics of IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 (sgp130) in elective patients undergoing cardiopulmonary bypass (CPB). IL-6, sIL-6R, and sgp130 were measured simultaneously and consecutively at 19 timepoints until the 10th postoperative day (POD). The proportion of pro- and anti-inflammatory pathways were determined by calculating sIL-6R/IL-6 and sIL-6R/sgp130 ratios. We analyzed 93 patients. IL-6 increased during surgery with reaching a plateau two hours after CPB and peaking on POD 1 (188.5 pg mL−1 (IQR, 126.6; 309.2)). sIL-6R decreased at the beginning of the surgical procedure, reaching a nadir level on POD 2 (26,311 pg mL−1 (IQR, 22,222; 33,606)). sgp130 dropped immediately after CPB initiation (0.13 ng mL−1 (IQR, 0.12; 0.15)), followed by a continuous recovery until POD10. The sIL-6R/IL-6 ratio decreased substantially at the beginning of the procedure, reaching a nadir on POD 1 (149.7 (IQR, 82.4; 237.4)), while the sIL-6R/sgp130 ratio increased simultaneously until 6 h post CPB (0.219 (IQR 0.18; 0.27)). In conclusion, IL-6 exhibited high inter-individual variability reflecting an inhomogeneous inflammatory response. Pro-inflammatory effects and overwhelming inflammation were rare and predominantly anti-inflammatory effects were found.
Highlights
Interleukin- 6 (IL-6) is a widely discussed biomarker in conjunction with extracorporeal circulation and inflammation during cardiac surgical interventions [1,2,3,4,5,6,7].Beside inflammation, IL-6 is involved in various processes with a complex signaling physiology based on two pathways [8]
The classic-signaling process is limited to cells with a membrane-bound IL-6 receptor (IL-6R), which is only found on hepatocytes and several leukocyte subpopulations [10,11]
We investigated the change in soluble form of the IL-6R (sIL-6R)/IL6 and sIL-6R/sgp130 ratio levels in the perioperative course, changes in intra- and postoperative fluid balances, and differences in postoperative phase angle, a marker of cell membrane integrity measured by bioelectrical impedance analysis (BIA)
Summary
IL-6 is involved in various processes with a complex signaling physiology based on two pathways [8]. In both pathways, a ligand/receptor complex is formed combined with a type I signal transducer protein glycoprotein (gp) gp130 [9]. The classic-signaling process is limited to cells with a membrane-bound IL-6 receptor (IL-6R), which is only found on hepatocytes and several leukocyte subpopulations [10,11]. The IL-6R and its ligand form an IL-6IL-6R complex, which associates with membranebound gp130. The classic-signaling process is associated with regenerative or anti-inflammatory effects [9,10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
