Blood-derived anti-inflammatory protein solution blocks the effect of IL-1β on human macrophages in vitro.

OBJECTIVE: The purpose of this research was to determine if an autologous protein solution (APS), prepared from platelet-rich plasma (PRP), could reduce the deleterious effects of inflammatory cytokines in vitro.
METHODS: APS was prepared by processing human blood in a tuned density buoy separation device (Platelet Separation System, Biomet Biologics, LLC) to produce platelet-rich plasma (PRP) and processing the PRP in a concentration device containing polyacrylimide beads to produce a highly concentrated anti-inflammatory solution. A functional assay was designed using recombinant interleukin (IL)-1β to upregulate IL-8 production by human monocytes. Either recombinant human interleukin-1 receptor antagonist (rhIL-1ra) or APS was added to some samples to determine if a reduced inflammatory response could be identified in vitro. The enzyme-linked immunosorbent assay (ELISA) method was employed to perform cytokine analyses, and Student's t test (α = 0.05) was used for all statistical analyses.
RESULTS: Both the rhIL-1ra and the APS reduced the effect of IL-1β on human macrophages in vitro. This was measured by the reduced production of IL-8 and tumor necrosis factor (TNF)-α. Further analysis of the supernatants confirmed the presence of high concentrations of IL-1ra and soluble TNF receptor I (sTNF-RI) with the APS treatment.
CONCLUSION: The ability of the APS to reduce the effect of IL-1β and limit the expression of other inflammatory cytokines in vitro validates its potential use as an autologous treatment for osteoarthritis.