Interictal plasma glutamate levels are elevated in individuals with episodic and chronic migraine

Glutamate is implicated in migraine pathogenesis including central sensitization and pain transmission. Altered plasma glutamate levels has been noted in migraine. Chronic migraine (CM) presented a higher degree of central sensitization and pain transmission than episodic migraine (EM). However, no study has evaluated plasma glutamate levels separately in EM and CM. This study aimed to assess plasma glutamate levels in EM and CM compared to controls. An enzyme-linked immunosorbent assay was used to assess plasma glutamate levels in females with EM (n = 98) and CM (n = 92) as well as controls (n = 50). Plasma glutamate levels in participants with EM (median and interquartile range, 49.73 [40.82-66.12] mu mol/L, p < 0.001) and CM (58.70 [44.64-72.46] mu mol/L, p < 0.001) were significantly higher than those in controls (38.79 [29.50-53.60] mu mol/L). Glutamate levels were not significantly different between participants with EM and CM (p = 0.075). There was no significant association of plasma glutamate levels with headache frequency (exponential and 95% confidence interval, 1.285 [0.941-1.755]) and intensity (mild, 59.95 [59.95-59.95] mu mol/L vs. moderate, 52.76 [40.83-106.89] mu mol/L vs. severe, 55.16 [42.34-68.03] mu mol/L, p = 0.472). The plasma glutamate level is a potential indicator for EM and CM.

Automated summary

Glutamate is implicated in migraine pathogenesis, and altered plasma glutamate levels have been noted in migraine patients. Chronic migraine is associated with higher levels of central sensitization and pain transmission compared to episodic migraine. This study found significantly higher plasma glutamate levels in both episodic and chronic migraine patients compared to controls, with no significant difference between the two migraine subtypes.