Interictal Amylin Levels in Chronic Migraine Patients: A Case-Control Study

Background Recently, amylin and its receptors were found in different structures involved in migraine pathophysiology. Here, we evaluate interictal concentrations of amylin and calcitonin gene-related peptide in peripheral blood as biomarkers for chronic migraine. Methods We prospectively recruited patients with episodic migraine, chronic migraine and healthy controls. Interictal amylin and calcitonin gene-related peptide levels were assessed in blood samples using enzyme linked immunosorbent assay. Results We assessed plasma samples from 58 patients with episodic migraine (mean age 37.71 +/- 10.47, 87.9% female), 191 with chronic migraine (mean age 46.03 +/- 11.93, 95% female), and on 68 healthy controls (mean age 43.58 +/- 11.08 years, 86% female). Body mass index was 25.94 +/- 4.53 kg/m(2) for migraine patients and 25.13 +/- 4.92 kg/m(2) for healthy controls (p = 0.0683). Interictal plasma amylin levels were higher in chronic migraine patients (47.1 pg/mL) than in the episodic migraine patients (28.84 pg/mL, p < 0.0001) and healthy controls (24.74 pg/mL, p < 0.0001). Plasma calcitonin gene-related peptide levels were increased (20.01 pg/mL) in chronic migraine patients when compared to healthy controls (11.37 pg/mL, p = 0.0016), but not to episodic migraine patients (18.89 pg/mL, p = 0.4369). Applying a cut-off concentration of 39.68 pg/mL plasma amylin, the sensitivity to differentiate chronic migraine from healthy controls was 57.6% and the specificity was 88.2%. Variables such as age, analgesic overuse, depression, allodynia, use of preventive medication or a history of aura did not influence the plasma concentrations of amylin or calcitonin gene-related peptide. Conclusion Interictal plasma amylin levels are higher in patients with chronic migraine and may serve as a diagnostic biomarker for chronic migraine.