Human Electrophysiological Model to Quantify the CGRP-related Axon Reflex of Trigeminal Afferents

The proposed project aims at establishing a neurophysiological biomarker for migraine. Migraine is one of the world's most disabling diseases and its prophylactic treatment is time and cost-consuming. Since each patient responds differently and unpredictably to preventive medication, physicians are forced to try prophylactic drugs one by one. Recently, a new group of therapeutic agents targeting the neuropeptide Calcitonin gene-related peptide (CGRP) has been launched for migraine treatment. CGRP is stored in trigeminal afferents and released to meningeal blood vessels during acute migraine attacks leading to a vasodilating response. In an experimental setting, the release of CGRP from afferent nerve fibers in the skin can be induced by transdermal electrical stimulation. The subsequently evoked skin erythema, called 'flare reaction', can be quantified by laser Doppler imaging techniques. Never before, research studies used this experimental model in either trigeminally innervated skin or migraine patients. I therefore propose to establish this model to 1) test the specificity of an evoked 'flare response' in the trigeminal territory for the pathophysiology of migraine, 2) investigate the effect of CGRP-targeting anti-migraine drugs on this outcome parameter and 3) evaluate the impact of this model to predict the treatment response to drugs interfering with the CGRP-pathway. This study is a highly innovative approach towards tailored migraine treatment.