Vascular smooth muscle cell dysfunction in patients with migraine.
Migraine is associated with increased risk of cardiovascular disease, but the mechanisms are unclear. To investigate the activity of endothelial and vascular smooth muscle cells (VSMCs) in patients with migraine. Case-control study of 12 patients with migraine without aura and 12 matched healthy control subjects. Endothelial and VSMC components of vascular reactivity were explored by plethysmography measurement of forearm blood flow (FBF) during infusions of vasoactive agents into the brachial artery. Forearm production of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) was also quantified. In patients with migraine, the vasodilating effect of acetylcholine (ACh), an endothelium-dependent vasodilator, was markedly reduced (p < 0.001 by analysis of variance). In response to the highest dose of ACh, FBF rose to 8.6 +/- 2.2 in patients with migraine and to 22.7 +/- 3.0 mL x dL(-1) x min(-1) in controls (p = 0.001). The dose-response curve to nitroprusside, a vasodilator directly acting on VSMCs, was depressed in patients with migraine (p < 0.001 by analysis of variance). The maximal response of FBF to nitroprusside was 12.1 +/- 2.0 in patients with migraine and 24.1 +/- 1.8 mL x dl(-1) x min(-1) in controls (p < 0.001). During ACh infusion, NO release from the endothelium was similar in patients and controls. In contrast, there was a marked release of cGMP from VSMCs in controls, but not in patients with migraine (-1.9 +/- 2.2 in patients with migraine and -19.1 +/- 5.4 nmol x dL(-1) x min(-1) in controls; p = 0.03). Patients with migraine are characterized by a distinct vascular smooth muscle cell dysfunction, revealed by impaired cyclic guanosine monophosphate and hemodynamic response to nitric oxide.