The role of calcitonin gene-related peptide and substance P in the pathogenesis of dialysis headache.

Aim: The present study aims to establish the role of serum CGRP and SP levels in the disease pathophysiology in patients with dialysis headache not accompanied by primary or secondary headaches, and also whether there is a correlation between these vasoactive peptides and the severity of headache.
Method: This study was designed as prospective and multicenter. A total of 30 dialysis headache patients and 30 patients without headache as the control group in the Nephrology outpatient clinics which implement similar dialysis procedures were included in the study. Blood samples were taken from all the patients before hemodialysis, and post-hemodialysis samples were collected. CGRP and SP contents in serum samples were measured using the ELISA method with detection kits.
Results: A total of 60 patients were included in the study with 17 female and 13 male patients in the dialysis headache group and 18 female and 12 male patients in the control group, and there were no significant differences in sex and age between the groups. CGRP levels in the headache group were found to be significantly higher compared with the control group both before and after hemodialysis. Furthermore, pre-hemodialysis CGRP levels were significantly higher than post-hemodialysis CGRP levels in both the headache and control groups. Serum SP levels in the headache group were found to be higher compared with the control group both before and after hemodialysis, there was no significant difference between the groups. Even though SP levels in both groups decreased after hemodialysis, there was again no significant difference between the groups. No correlation was found between the patients' severity of headache and serum CGRP and SP levels.
Conclusion: This study concludes that CGRP and SP, even though the latter is not statistically significant, play a role in the pathophysiology of the dialysis headache, and further studies with a larger and more specific patient population may reveal the relationship between the neuropeptides and dialysis headache more clearly.
(© 2023 International Society for Hemodialysis.)