Elevated inflammatory cytokine expression in CSF from patients with symptomatic thoracic disc herniations correlates with increased pain scores

Publication date: Available online 2 August 2018

Source: The Spine Journal

Author(s): Pablo Andrade, Erwin M.J. Cornips, Claudia Sommer, Marc A. Daemen, Veerle Visser-Vandewalle, Govert Hoogland

Abstract

Background

The pathophysiology of pain in symptomatic thoracic disc herniation (TDH) patients remains poorly understood. Mere mechanical compression of the spinal cord and/or the exiting nerve root by a prolapsed disc cannot explain the pathogenesis of pain in all cases. Previous studies report a direct correlation between the levels of proinflammatory cytokines in disc biopsies and the severity of leg pain in patients with lumbar disc herniations. A similar correlation in patients with TDHs has not been investigated.

Purpose

To correlate the cerebrospinal fluid (CSF) expression of cytokines and pain-related amino acids with preoperative pain scores in patients with symptomatic TDHs.

Study Design

A prospective human study of CSF samples and clinical outcome scores.

Methods

Using ELISA and high-performance liquid chromatography (HPLC), we determined inflammatory cytokine levels (TNF-α, IL-1β and IL-10) and amino acid levels (glutamate, aspartate, GABA, glycine and arginine) in CSF samples from ten TDH patients and ten control subjects who did not suffer an inflammatory disease nor pain related to spinal cord compression, and subsequently correlated these levels with preoperative pain scores. Differences between both groups were evaluated by a Whitney-U-test. In order to estimate the correlation between cytokine or amino acid expression and pain scores, data were analyzed using linear regression analysis.

Results

No inflammatory cytokines were found in CSF samples from control subjects, whereas TNF-α, IL-1β and IL-10 were detectable by ELISA in all CSF samples from TDH patients. TNF-α and IL-10, but not IL-1β levels moderately correlated with preoperative pain scores. Elevated TNF-αlevels positively correlated with high pain scores; elevated IL-10 levels negatively correlated with high pain scores. Amino acids were detectable in all samples from both groups. There were no significant differences between the groups in any of the amino acids measured with HPLC.

Conclusion

Increased proinflammatory cytokine expression is associated with elevated pain scores in symptomatic TDH patients. On the other hand, there is no conclusive correlation between the intensity of pain and the local or systemic presence of amino acids associated with pain transmission.

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