HEPATIC RELEASE OF INTERLEUKIN-10 DURING CARDIOPULMONARY BYPASS IN STEROID-PRETREATED PATIENTS

With its antiinflammatory properties, interleukin (IL)-10 may play an important role in limiting complications associated with cardiopulmona ry bypass (CPB). We previously demonstrated that pretreatment with ste roids can significantly increase IL-10 production during CPB, but neit her the heart nor the lung was found to be its main source. To define whether the liver is the source of IL-10, hepatic venous cannulation w as performed in 12 patients undergoing CPB. Each patient received 30 m g/kg of methylprednisolone before operation. Plasma levels of IL-10 we re simultaneously measured in peripheral arterial blood and hepatic ve nous blood before heparin administration, before aortic cross-clamping , and 5, 30, 60, 90, and 120 minutes after aortic declamping. The dura tion of CPB and aortic cross-clamping was 113 +/- 7 minutes and 75 +/- 6 minutes (mean +/- SEM), respectively. IL-10 levels 30 minutes after declamping were significantly higher in hepatic venous blood than in arterial blood (1187 +/- 573 pg/ml vs 911 +/- 405 pg/ml, p < 0.01 by W ilcoxon's signed-rank test). To determine whether steroids can also in duce the release of another antiinflammatory cytokine, IL-4, plasma IL -4 levels were measured simultaneously. IL-4 was detected in the arter ial blood of only 4 of the 12 patients, transiently after aortic decla mping. IL-4 was not detected in hepatic venous blood. In conclusion, t he liver is a major source of IL-10 during CPB. However, steroid-treat ed patients do not show an increase in IL-4, and the liver is not the source of IL-4 during and after CPB.