Platelet-rich plasma increases matrix metalloproteinases in cultures of human synovial fibroblasts.

BACKGROUND: The effect of platelet-rich plasma on chondrocytes has been studied in cell and tissue culture. Less attention has been given to the effect of platelet-rich plasma on nonchondrocytic cell lineages within synovial joints, such as fibroblast-like synoviocytes, which produce cytokines and matrix metalloproteinases (MMPs) that mediate cartilage catabolism. The purpose of the present study was to determine the effect of platelet-rich plasma on cytokines and proteases produced by fibroblast-like synoviocytes.

METHODS: Platelet-rich plasma and platelet-poor plasma from harvested autologous blood were prepared with a commercially available system. Fibroblast-like synoviocytes were treated with platelet-rich plasma, platelet-poor plasma, recombinant PDGFββ (platelet-derived growth factor ββ), or phosphate-buffered saline solution and incubated at 37°C for forty-eight hours. The concentrations of IL-1β (interleukin-1β), IL-1RA (IL-1 receptor antagonist), IL-6, IFN-γ (interferon-γ), IP-10 (interferon gamma-induced protein 10), MCP-1 (monocyte chemotactic protein-1), MIP-1β (macrophage inflammatory protein-1β), PDGFββ, RANTES, TNF-α (tumor necrosis factor-α), VEGF (vascular endothelial growth factor), MMP-1, MMP-3, and MMP-9 in the culture medium were determined by multiplex immunoassay.

RESULTS: Platelet-rich plasma cultured in medium contained multiple catabolic mediators in substantial concentrations, including MMP-9 (15.8 ± 2.3 ng/mL) and MMP-1 (2.5 ± 0.8 ng/mL), as well as proinflammatory mediators IL-1β, IL-6, IFN-γ, IP-10, MCP-1, MIP-1β, RANTES, and TNF-α in concentrations between 20 pg/mL and 20 ng/mL. Platelet-poor plasma contained significantly lower concentrations of these compounds. Platelet-rich plasma was used to treat human fibroblast-like synoviocytes, and the resulting concentrations of mediators were corrected for the concentrations in the platelet-rich plasma alone. Compared with untreated fibroblast-like synoviocytes, synoviocytes treated with platelet-rich plasma exhibited significantly greater levels of MMP-1 (363 ± 94.0 ng/mL, p = 0.018) and MMP-3 (278 ± 90.0 ng/mL, p = 0.018). In contrast, platelet-poor plasma had little effect on mediators secreted by the synoviocytes. PDGFββ-treated fibroblast-like synoviocytes exhibited a broad proinflammatory cytokine response at four and forty-eight hours.

CONCLUSIONS: Platelet-rich plasma was shown to contain a mixture of anabolic and catabolic mediators. Synoviocytes treated with platelet-rich plasma responded with substantial MMP secretion, which may increase cartilage catabolism. Synoviocytes responded to PDGF with a substantial proinflammatory response.