Medication overuse headache is associated with elevated lipopolysaccharide binding protein and pro-inflammatory molecules in the bloodstream

Abstract

Objective: Medication overuse headache (MOH) is a secondary headache that accompanies chronic migraine. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequently used analgesics worldwide and they are known to induce leaky gut. In this study, we aimed to investigate whether NSAID induced MOH is associated with altered circulating lipopolysaccharide binding protein (LBP) levels and inflammatory molecules.

Materials and methods: Piroxicam (10 mg/kg/day, po) for 5 weeks was used to induce MOH in female Sprague Dawley rats. Pain behavior was evaluated by periorbital withdrawal thresholds, head-face grooming, freezing, and head shake behavior. Serum samples and brain tissues were collected to measure circulating LBP, tight junction protein occludin, adherens junction protein vascular endothelial (VE)-cadherin, calcitonin gene-related peptide (CGRP), IL-6 levels and brain high mobility group box-1 (HMGB1) and IL-17 levels.

Results: Chronic piroxicam exposure resulted in decreased periorbital mechanical withdrawal thresholds, increased head-face grooming, freezing, and head shake behavior compared to vehicle administration. Serum LBP, CGRP, IL-6, IL-17, occludin, VE-cadherin levels and brain IL-17 and HMGB1 levels were significantly higher in piroxicam group compared to controls. Serum LBP was positively correlated with occludin (r = 0.611), VE-cadherin (r = 0.588), CGRP (r = 0.706), HMGB1 (r = 0.618) and head shakes (r = 0.921), and negatively correlated with periorbital mechanical withdrawal thresholds (r = -0.740).

Conclusion: Elevated serum LBP, VE-cadherin and occludin levels indicating disrupted intestinal barrier function and leakage of LPS into the systemic circulation were shown in female rats with MOH. LPS induced low-grade inflammation and elevated nociceptive and/or pro-inflammatory molecules such as HMGB1, IL-6, IL-17 and CGRP may play a role in the development and maintenance of MOH. Interference with leaky gut and pro-inflammatory nociceptive molecules could also be a target for sustained management of MOH.

Keywords: HMGB1; IL-17; Inflammation; LBP; LPS; Leaky gut; MOH; Migraine; Occludin; VE–cadherin.

Fig. 1

Experimental design of the study

Fig. 2

Behavioral results of female Sprague Dawley rats exposed to chronic piroxicam (MOH) or vehicle (Control). Compared to the control group, A the total duration of grooming, B total duration of freezing and C the number of head shakes were significantly higher in MOH group. Data were shown as mean ± SEM. Normality of data was evaluated with the Kolmogorov–Smirnov test. Statistical analysis was performed with Mann–Whitney’s U test

Fig. 3

Mechanical withdrawal thresholds of female Sprague Dawley rats exposed to chronic piroxicam (MOH) or vehicle (Control). The mechanical withdrawal thresholds were significantly lower in MOH group. Data were shown as mean ± SEM. Statistical analysis was performed with 2-way analysis of variance for repeated measures. Post-hoc multiple comparisons were performed using Šidák’s multiple comparisons test

Fig. 4

Serum levels of circulating biomarkers of leaky gut, inflammation and pain in female Sprague Dawley rats exposed to chronic piroxicam (MOH) or vehicle (Control). Compared to the control group, serum levels of A CGRP, B LBP, C occludin, D VE-cadherin, E IL-6 and F IL-17 levels were significantly higher in MOH group compared to the control group. Data were shown as mean ± SD. Statistical analysis was performed with student t-test for CGRP, LBP and occludin and Mann–Whitney’s U test for VE-cadherin, IL-6 and IL-17

Fig. 5

Cerebral cortical levels of inflammatory molecules of female Sprague Dawley rats exposed to chronic piroxicam (MOH) or vehicle (Control). Compared to the control group, cortical A HMGB1 and B IL-17 levels were significantly higher in MOH group. Data were shown as mean ± SD. Statistical analysis was performed with student t-test