HEPARIN COATING REDUCES CELL ACTIVATION AND MEDIATOR RELEASE IN AN IN-VITRO VENOVENOUS BYPASS MODEL FOR LIVER-TRANSPLANTATION

We used an in vitro model for venovenous bypass in a prospective, rand omized study to analyze the effect on leukocytes cell activation after coating the total blood contact surface with covalently bound heparin . In ten experiments heparin-coated circuits were used, and in ten oth er experiments noncoated circuits were used. Monocyte cytokine product ion and neutrophil myeloperoxidase release were analyzed. Monocytes we re isolated using anti-CD14 paramagnetic beads, and oligo(dT)(25) bead s were used to isolate mRNA before subsequent reverse transcription an d semiquantitative amplification of various cytokines in order to dete rmine time-related changes in expression during bypass. After 2 h, mRN As for IL-1 beta and IL-6 were highly upregulated in noncoated compare d to heparin-coated circuits. Little or no change was seen in the expr ession of other cytokines. IL-1 beta and IL-6 were measured in plasma after 12 h and reflected the upregulated mRNAs in noncoated circuits. A significantly reduced release of myeloperoxidase was observed in coa ted versus noncoated circuits. This indicates that heparin-coated surf aces reduce cellular activation and the release of inflammatory mediat ors.