Differential immune activation during simulated cardiopulmonary bypass procedure using freshly drawn and week-old...

The goal of this study is to assess whether the use of different aged blood, used during the simulated PennState Hershey Pediatric cardiopulmonary bypass (CPB)model affects immune activation. In order to study and compare the cytokine release involved in the humoral immune response during simulated CPB, both freshly drawn whole blood used less than 1 h after donation (n = 2)and reconstituted whole blood (1 week old) (n = 3) were circulated in a simulated CPB circuit under identical perfusion conditions. Discrete samples were collected in both experiments and analyzed for the proinflammatory cytokines concentrations of tumor necrosis factor-alpha, interleukin(IL)-6, and IL-8 using immunofluorocytometry as an indicator of immune activation. The results indicated that the cytokine concentrations of freshly drawn blood increased significantly compared with the reconstituted blood over the CPB circulation time. The fresh blood activation was two to three orders of magnitude larger than the week-old blood for all cytokines analyzed. These results suggest that the use of freshly drawn blood is required to evaluate immune responses to the extracorporeal circulation.