INCREASE IN PORTAL BLOOD INTERLEUKIN-6 SOON AFTER THE COMMENCEMENT OFDIGESTIVE SURGERY

To determine whether cytokines produced in the operative field during digestive surgery selectively spill over into the portal blood, the ch anges in interleukin-6 (IL-6) levels in portal and peripheral venous b lood were assayed at several points in time from the commencement of s urgery until 14 days later, in 11 patients. Similar changes in the IL- 6 levels were observed in the portal and peripheral blood samples; how ever, the IL-6 levels in the portal blood reached a maximum 6-12 h aft er the commencement of surgery, being earlier than in the peripheral v enous blood. In fact, between 3 and 12 h after the commencement of sur gery, the IL-6 levels were higher in the portal blood by 33-81 pg/ml. By 24 h or more after the commencement of surgery, the IL-6 levels did not differ significantly in the two types of blood samples. Moreover, the C-reactive protein levels 2 days after surgery were even more clo sely correlated to the maximum IL-6 levels in the portal blood than to those in the peripheral venous blood. These results suggest that IL-6 produced during intraabdominal digestive surgery initially enters the portal blood, being trapped by IL-6 receptors in the liver, where it may regulate the synthesis of acute-phase proteins as a hepatocyte-sti mulating factor.