Many previous studies have put some insights into the fact that pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) plays a prominent role in the activation of the trigeminovascular system. A considerable relationship between interictal plasma PACAP38-LI and diffusion parameters of the white matter in patients with migraine in the occipital white matter has been demonstrated.

The present study was conducted to investigate if interictal plasma pituitary adenylate cyclase-activating peptide 38-like immunoreactivity (PACAP38-LI) has a relationship with microstructural integrity of the white matter in migraine.

In 26 patients (24 women) with migraine who underwent diffusion tensor imaging afterwards using a 1.5-tesla magnetic resonance scanner, radioimmunoassay was used to evaluate the interictal plasma PACAP38-LI.  Tract-based spatial statistics present in the FMRIB's Software Library was used to analyze data.

Interictal plasma PACAP38-LI showed considerable relation with mean diffusivity (p < 0.0179), primarily in the bilateral occipital white matter scattering into the temporal and parietal white matter.  A positive link between interictal PACAP38-LI in the left optic radiation, and left posterior corpus callosum and axial, and radial diffusivity was observed. There was no considerable relationship noted between PACAP38-LI and fractional anisotropy. The disease duration was considered as nuisance regressor in the model. Association of PACAP38-LI with mean and axial diffusivity in the left thalamus was observed.

The authors reported a correlation between imaging markers of the disease and PACAP38, a pathobiologically crucial neurochemical biomarker. This correlation will strengthen future research, aimed to explore the role of PACAP38 in migraine.