The Effect of Methylprednisolone on Cytokine Concentration and Leukocyte Adhesion Molecule Expression

This study examines the effect of methylprednisolone on cytokine balance and adhesion molecule expression within an isolated cardiopulmonary bypass (CPB) system. This isolated CPB system is an in vitro model which simulates the pro-inflammatory immune response. Whole blood from 10 volunteers was obtained in two equal amounts. Heparin and saline were added to the control group while heparin and methylprednisolone were added to the methylprednisolone group. The blood was added to two identical CPB circuits and bypass commenced by a trained perfusionist. Samples were taken at blood donation (Sample 0), 10min after the addition of drugs (Sample 1) and after 30, 60 and 90min of CPB (Samples 2, 3 and 4, respectively). Cytokines interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1ra) and tumour necrosis factor soluble receptor 2 (TNFsr2) and the leucocyte adhesion molecules L-selectin, HLA DR, CD18 and CD11b were determined. IL-8 increased in both groups. This increase was significantly less in the methylprednisolone group. Increases in granulocyte CD11b and CD18 expression were less in the methylprednisolone group than in the control group but did not reach statistical significance. These results indicate that methylprednisolone significantly reduces the production of IL-8 in an isolated CPB system. This effect occurs in the absence of IL-10.