Longitudinal changes of serum cytokines in patients with chronic low back pain and Modic changes.

OBJECTIVES: To explore serum cytokine levels over time in patients with chronic low back pain (cLBP) and Modic changes (MCs), difference in change between treatment groups in the Antibiotics in Modic Changes (AIM) study and associations between change in cytokines and low back pain. METHODS: Serum concentrations of 39 cytokines were measured at baseline and 1 year from 73 participants in the AIM study; 30 randomized to placebo, 43 to Amoxicillin. Low back pain intensity was measured by numeric rating scale. Change in cytokine levels over time were assessed by paired t-tests. Difference in change in cytokine levels between treatment groups and associations between changes in LBP and cytokine levels were assessed by linear regression models. Networks of cytokine changes in each treatment groups were explored by Pearson's correlations. RESULTS: Five cytokines changed from baseline to 1 year, (mean change, log transformed values with CI) C-X-C motif chemokine ligand (CXCL) 10 (IP-10) (0.11 (0.01-0.20)), CXCL13 (0.61 (0.00-0.12)), C-C motif chemokine ligand (CCL)26 (0.05 (0.01-0.1)), granulocyte macrophage-colony stimulating factor (GM-CSF) (-0.12 (-0.23 to 0.00)) and CXCL11 (0.12 (0.03-0.22)). Treatment group only influenced change in CCL21 (ß 0.07 (0.01-0.12)), and IL-6 (ß -0.17 (-0.30 to -0.03)). Change in CXCL13 (ß 2.43 (0.49-4.38)), CCL27 (ß 3.07 (0.46-5.69)), IL-8 (ß 1.83 (0.08-3.58)) and CCL19 (ß 3.10 (0.86-5.43)) were associated with change in LBP. The correlation networks of cytokine changes demonstrate small differences between treatment groups. CONCLUSIONS: Cytokine levels are relatively stable over time in our sample, with little difference between treatment groups. Some cytokines may be associated with LBP intensity. The differences between the correlation networks suggest that long-term Amoxicillin-treatment may have longstanding effects to be further explored.

Association between baseline IL-6 and 1-year recovery in lumbar radicular pain.

BACKGROUND: In the present study, the influence of cytokines on 1-year recovery in lumbar radicular pain was examined. METHODS: In total, 110 patients with symptomatic lumbar disc herniation were followed for 1 year. Uni- and multivariate linear regression was used to assess the influence of interleukin (IL)-6, IL-8, disc degeneration and endplate changes (Modic changes) on the changes in the Oswestry Disability Index (ODI change; primary outcome) and visual analogue scale (VAS) for low back pain (LBP) and leg pain (secondary outcomes). RESULTS: Less favourable ODI outcome correlated with higher serum IL-6 levels (B = -3.41, 95% CI -5.52 to -1.30, p = 0.002), non-surgical treatment (B = -7.03, 95% CI 1.21 to 12.84, p = 0.018), higher baseline back pain intensity (B = -2.28, 95% CI -3.21 to -1.35, p < 0.001) and low educational level (B = -5.57, 95% CI 0.66 to 10.47, p = 0.027). High VAS for LBP and leg pain at 1 year was associated with high levels of serum IL-6, higher back pain intensity and longer duration of lumbar radicular pain at baseline. CONCLUSIONS: High serum IL-6 levels, but not disc degeneration or Modic changes, were associated with less favourable recovery in patients with lumbar radicular pain. Intense initial back pain, non-surgical treatment, lower educational level and longer duration of radicular pain before treatment also correlated with a slower recovery the first year after disc herniation.

The COMT rs4680 Met allele contributes to long-lasting low back pain, sciatica and disability after lumbar disc herniation.

BACKGROUND: The COMT enzyme metabolizes catecholamines and thus modulates adrenergic, noradrenergic and dopaminergic signaling. A functional polymorphism in the gene encoding this enzyme, i.e. the COMT Val158Met SNP that reduces enzyme activity, has previously been linked to pain sensitivity. METHODS: We examined if the COMT Val158Met SNP could contribute to discogenic subacute low back pain and sciatica by comparing the frequency of the Val158Met genotypes of degenerative disc disease patients with healthy controls. Moreover, we examined if this SNP could predict the clinical outcome, i.e. the progression of pain and disability. RESULTS: The present data demonstrated that there were no differences in COMT genotype frequencies between the newly diagnosed patients and controls. Analysis of pain and disability in the patients over time revealed, however, a significant or border-line significant increase in McGill sensory score and Oswestry Disability Index (ODI) score for individuals with COMT Met/Met genotype. Furthermore, significant associations between the COMT Met-allele and VAS activity score, McGill sensory score and ODI score were observed in the patients 6 months after inclusion. DISCUSSION: Although the Val158Met SNP was not a risk factor for disc herniation, patients with Met/Met had more pain and slower recovery than those with Val/Met, which in turn also had more pain and slower recovery than those with Val/Val suggesting the SNP contributes to the progression of the symptoms of disc herniation. CONCLUSION: We conclude that the functional COMT Val158Met SNP contributes to long lasting low back pain, sciatica and disability after lumbar disc herniation.