Quantitative in vivo cytokine analysis at synthetic biomaterial implant sites

To further elucidate the foreign body reaction, investigation of cytokines at biomaterial implant sites was carried out using a multiplex immunoassay and ELISA. Macrophage activation cytokines (IL-1 beta, IL-6, and TNF alpha), cytokines important for macrophage fusion (IL-4 and IL-13), anti inflammatory cytokines (IL-10 and TGF beta), chemokines (GRO/KC, MCPA.), and the T-cell activation cytokine IL-2 were quantified at biomaterial implant sites. Empty cages (controls) or cages containing synthetic biomedical polymer (Elasthane 80A (PEU), silicone rubber (SR), or polyethylene terephthalate (PET)) were implanted subcutaneously in Sprague-Dawley rats for 4, 7, or 14 days, and cytokines in exudate supernatants and macrophage surface adhesion and fusion were quantified. The presence of a polymer implant did not affect the levels of IL-1 beta, TGF beta, and MCP-1 in comparison to the control group. IL-2 was not virtually detected in any of the samples. Although the levels of IL-4, IL-13, IL-10, and GRO/KC were affected by polymer implantation, but not dependent on a specific polymer, IL-6 and TNF alpha were significantly greater in those animals implanted with PEU and SR, materials that do not promote fusion. The results indicate that differential material-dependent cytokine profiles are produced by surface adherent macrophages and foreign body giant cells in vivo. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 152-159, 2009