Expression of miR-155 in migraine: association with migraine phenotypes and disease severity

This is a cross-sectional and controlled study. We have considered three study groups: healthy controls (HCs), episodic migraine (EM) and chronic migraine with medication overuse headache (CM-MOH). Demographic features were comparable among the three study groups. We assessed the expression of miR-155 (Relative Quantification - RQ) in peripheral blood monocytes. All determinations were performed in the inter-ictal migraine phase. We analysed miR-155 expression in 30 HCs (0.44 ± 0.18 RQ), 52 EM (1.46 ± 0.85 RQ), and 44 CM-MOH (2.68 ± 2.47 RQ) subjects. Migraine patients showed higher miR-155 expression when compared to HCs (p=0.001). In addition, miR-155 expression was higher in CM-MOH patients when compared to EM group (p=0.006). This finding was confirmed in a logistic regression model (EM vs CM-MOH; p = 0.022), after controlling for age, sex, ongoing preventive treatment, smoking and comorbidities.