The spectrum of microvascular ultrastructural changes in the subpopulation of patients with migraine and cerebral white matter hyperintensities on MRI

Introduction
Migraine is considered not only as a separate clinical entity but also as a symptom of various brain disorders, including cerebral small vessel diseases. Since cerebral small vessel diseases are usually general angiopathies, evaluation of biopsy material other than brain tissue may help in their diagnosis in vivo. In patients with migraine, brain magnetic resonance imaging (MRI) often shows hyperintense changes in the cerebral white matter. Such changes may indicate the symptomatic nature of migraine and coexisting structural or biochemical vascular abnormalities.

Material and methods
To verify the hypothesis of the symptomatic nature of migraine in patients with abnormal brain neuroimaging, we performed an ultrastructural examination of skin and skeletal muscle vessels in biopsy material from 40 patients with clinically diagnosed migraine and hyperintense white matter lesions on MRI.

Results
In 80% of the examined patients, ultrastructural examination showed various pathological changes in the microvessels including abnormalities characteristic of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and elastin disorders, as well as less specific changes such as thickening of the basal lamina, narrowing of the vessel lumen, degeneration of the vessel wall cells, endothelial activation, oncosis-like changes, and the presence of various types of deposits in the vessel wall. In 20% of the examined cases, ultrastructural examination of the vessels was normal.

Conclusions
Patients with migraine and hyperintense cerebral white matter changes on MRI have an increased risk of concomitant microangiopathy. In this group of patients, skin-muscle biopsy allows the identification of cases with coexisting vessel abnormalities.