Peripheral, Interictal Serum S100B Levels are Not Increased in Chronic Migraine Patients.

Background: The trigemino‐vascular system (TVS) plays a key role in migraine pathophysiology. Glial cells are abundant in the TVS system and mainly in the trigeminal ganglion. S100B protein is a calcium‐binding protein, found in the cytoplasm of glial cells in the central nervous system, which is released in response to inflammatory stimuli. Previous works analyzing S100B in migraineurs have offered contradictory results. Objective: In this case‐control study, we analyzed serum levels of S100B as a possible biomarker of the glial TVS activation in chronic migraine (CM). Patients and Methods: The study group consisted of patients attending our clinic with CM and, as control groups, patients with episodic migraine (EM), cluster headache (CH) outside of a bout and healthy volunteers (HV) with no headache history. S100B levels were determined interictally in peripheral blood samples by ELISA. Results: We assessed serum samples from 43 patients with CM, 19 with EM, 29 HV (mostly women), and 22 with (CH). S100B levels in CM (mean 22.9 ± 9.8 pg/mL) were not different (P =.727) when compared to EM patients (21.2 ± 9.3 pg/mL), difference of 1.7 (95% CI −5.7 to 8.9), CH patients (22.4 ± 7.8 pg/mL), difference of 0.5 (−5.7 to 6.7), and HV (20.6 ± 8.3 pg/mL), difference of 2.3 (−3.7 to 8.3). Conclusion: In contrast to other neuropeptides such as calcitonin gene‐related‐peptide and vasoactive intestinal peptide, which are increased in CM, interictal serum S100B levels are not elevated in these patients. According to our results, S100B levels do not seem to be a useful peripheral biomarker of the glial TVS activation in CM. [ABSTRACT FROM AUTHOR]