Inflammatory response of intervertebral disc cells is reduced by fibrin sealant scaffold in vitro

Intervertebral disc (IVD) degeneration is a complex process characterized by elevated concentrations of proinflammatory cytokines and proteolytic enzymes. Because of pro-healing constituents, we hypothesized that fibrin sealant (FS) can reduce inflammation and augment soft tissue healing within the damaged or degenerative IVD. To test this, human and porcine nucleus pulposus (NP) and annulus fibrosus (AF) cells were extracted from tissues and encapsulated into alginate beads (NP cells) and type I collagen sponges (AF cells). Half of the alginate and collagen scaffolds were embedded in FS. To provoke inflammatory behaviours, the constructs were cultured with and without continuous IL-1 (10 ng/ml) for 4, 7 and 14 days. ELISA was used to quantify the cellular synthesis (ng/mu g DNA) of clinically relevant cytokines, proteolytic enzymes and growth factors. In NP cell constructs with IL-1, the syntheses of TNF, IL-1, IL-6, IL-8 was elevated at all culture durations. In the presence of FS, secretion of several pro-inflammatory cytokines were significantly reduced [IL-6 and IL-8 (porcine); and TNF, IL-1, IL-6, IL-8 (human)]. Consistent with these reductions, human NP cultures exposed to FS and FS+IL-1 synthesized significantly reduced amounts of MMP-1 and -3 compared to constructs with IL-1. For porcine and human AF cells, there were no significant differences in the synthesis of the inflammatory or proteolytic cytokines relative to controls (without IL-1) at any culture duration. However, the porcine AF cells exposed to FS synthesized elevated amounts of the anti-inflammatory cytokine IL-4. The results suggest that FS may have beneficial effects for patients with degenerated intervertebral discs. Copyright (c) 2012 John Wiley & Sons, Ltd.