Ictal and Interictal Inflammatory Markers in Migraine

Migraine is a common, chronic disorder, which presents with recurrent episodes of disabling headache and affects approximately 12% of American adults.1,2 No biomarkers exist to identify episodic or chronic migraine sufferers; and the diagnosis relies solely on clinical criteria. Further the full pathophysiology of migraine has not been fully delineated, although our understanding of migraine pathophysiology has dramatically improved over the past 15 years. Current theories suggest that migraine is a neurovascular disorder, with the pain of migraine a result of the release of inflammatory neuropeptides from nerve endings in the activated trigeminal system (neurogenic inflammation), ultimately resulting in vasodilation, plasma extravasation and mast cell degranulation.3-6 Several inflammatory markers have been implicated in the pathway resulting in the neurogenic inflammation of migraine including calcitonin gene related peptide (CGRP), substance P (SP), neurokinin A, and multiple cytokines such as interleukin (IL) -1, IL-6 and tumor necrosis-α (TNF-α).5,7-10 More recent research supports that the odds of migraine are increased in those who are obese and that several adipose tissue derived cytokines (adipocytokines) may contribute to the neurogenic inflammation of migraine, including leptin and adiponectin. In one small pilot study of 33 participants evaluating chronic and episodic migraineurs as compared to controls, adiponectin (an adipocytokine) was significantly elevated in chronic migraineurs as compared to controls. A second study reported low levels of another adipocytokine, leptin in episodic migraineurs. However, all of these studies have evaluated only 3 to 4 of cytokines at the same time point and 11 none have evaluated adipocytokines during an acute attack. We hypothesize that obesity-related cytokines contribute to the neurogenic inflammation of migraine and have the potential be useful as biomarkers for episodic and chronic migraine as well as new drug targets for the treatment of migraine. To this end we propose to evaluate serum levels of obesity-related cytokines in migraineurs, ictally (during an acute migraine attack), following treatment with sumatriptan/naproxen sodium (Treximet®) and interictally (at baseline) when pain free.