Plasma and saliva levels of nerve growth factor and neuropeptides in chronic migraine patients

Abstract

To investigate the level and interrelationship of nerve growth factor (NGF) and sensory neuropeptides [substance P (SP), calcitonin gene-related peptide (CGRP)] in plasma and saliva of chronic migraine patients, and to analyze the association between pain intensity and their concentration. Plasma and resting whole saliva were collected from 33 chronic migraine patients and 36 control subjects. NGF, SP, and CGRP concentrations were measured by enzyme immunoassay and pain intensity of each subject was measured using the Graded Chronic Pain Scale. Chronic migraine patients showed higher NGF and neuropeptide levels in both plasma and saliva compared to the control subjects. Plasma NGF, and plasma and saliva levels of SP and CGRP were highly associated with pain intensity. There was a significant positive correlation between NGF and both neuropeptide levels in plasma, and between the neuropeptide levels in both plasma and saliva. Plasma levels of SP and CGRP were significantly correlated with their saliva level. The increased production of NGF and sensory neuropeptides may play an important role in the maintenance of pain in chronic migraine and analysis results of human saliva could act as an index of disease state and therapeutic outcome.