Is the fibronectin-aggrecan complex present in cervical disk disease?

OBJECTIVE

To investigate the presence of inflammatory cytokines and the fibronectin-aggrecan complex (FAC) in persons undergoing surgical treatment for cervical radiculopathy caused by disk herniation.

DESIGN

Single-center, prospective, consecutive case series.

SETTING

A single large academic institution.

PATIENTS: A total of 11 patients with radiculopathic pain and magnetic resonance imaging findings positive for disk herniation elected to undergo single-level cervical diskectomy. METHODS OR INTERVENTIONS: Lavage was performed by needle injection and aspiration upon entering the disk space for fluoroscopic localization before diskectomy.

MAIN OUTCOME MEASUREMENTS: The lavage fluid was assayed for pH and the FAC, as well as for the cytokines interleukin-6 (IL-6), interferon-γ, monocyte chemotactic protein (MCP), and macrophage inhibitory protein-1β.

RESULTS

The subjects were 7 women and 4 men with a mean age of 50.6 years (SE 9.7; range, 36-70 years). The mean concentrations (SE; range) in picograms per milliliter were 7.9 (4.4; 0-44) for IL-6, 25.3 (15.5; 0-159) for interferon-γ, 16.1 (11.9; 0-121) for MCP, and 6.1 (2.8; 0-29) for macrophage inhibitory protein-1β. The optical density of the FAC at 450 nm was 0.151 (0.036; 0.1-0.32), and the pH was 6.68 (0.1; 6.10-7.15). Statistically significant correlations were found between MCP and FAC (P = .036) and between FAC and pH (P = .008).

CONCLUSIONS

Biochemical analysis of injured cervical intervertebral disks reveals the presence of inflammatory markers such as MCP, fragments of structural matrix proteins such as FAC, and a correlation with pH. Further evaluation of the FAC as a potential diagnostic biomarker or therapeutic target is warranted in the cervical spine.