Artificial Surface-Induced Cytokine Synthesis: Effect of Heparin Coating and Complement Inhibition

Background:

Contact between blood and artificial surfaces induces an inflammatory response including activation of leukocytes and platelets, as well as complement and other plasma cascade systems. In the present study we investigated the roles of complement and surface modification in polyvinylchloride-induced cytokine production.

Methods:

Human whole blood was incubated in rotating loops of polyvinylchloride or heparin-coated polyvinylchloride tubing for 4 hours. Plasma concentrations of the cytokines tumor necrosis factor , interleukin (IL) 1ß, IL-6, IL-8, IL-10, and monocyte chemoattractant protein 1 (MCP-1) were quantified.

Results:

Polyvinylchloride induced a substantial increase in IL-8 and MCP-1, which was abolished by cycloheximide, indicating that they were synthesized during incubation. Interleukin 8 synthesis was completely complement-dependent since it was abolished by neutralizing antibodies to factor D and complement factor 5, as well as by a complement factor 5a receptor antagonist. Monocyte chemoattractant protein 1 synthesis was reduced by approximately half the amount by the complement inhibitors. Heparin-coated polyvinylchloride efficiently prevented synthesis of both IL-8 and MCP-1. Addition of recombinant human complement factor 5a to blood incubated in heparin-coated polyvinylchloride restored IL-8 and MCP-1 production completely and partly, respectively. In contrast to IL-8 and MCP-1, tumor necrosis factor , IL-1ß, interleukin 6 and IL-10 increased only marginally. A minor but significant increase in IL-1ß was complement-dependent, whereas a similar increase in IL-10 was completely prevented by heparin-coated polyvinylchloride. No significant changes were observed for tumor necrosis factor and IL-6.

Conclusions:

Polyvinylchloride induced a marked increase in IL-8 and MCP-1, in contrast to a marginal increase in tumor necrosis factor , IL-1ß, IL-6, and IL-10. The increase in IL-8 and MCP-1 was prevented by heparin-coated polyvinylchloride. Interleukin 8 production was totally complement-dependent and mediated by complement factor 5a.