Tryptophan metabolism in children with migraine: The role of kynurenine pathway

Background: Migraine is a common neurological disorder in children, significantly impacting quality of life and academic performance. The kynurenine pathway, a major metabolic route of tryptophan, plays a critical role in neuroinflammation and neurotransmission, yet its involvement in pediatric migraine remains unexplored. This study aims to investigate alterations in kynurenine pathway metabolites in children with migraine and assess their correlation with headache frequency and severity. Methods: A case-control study was conducted including pediatric patients diagnosed with migraine (n = 45) and healthy controls (n = 48). Serum levels of tryptophan (TRP) and its kynurenine pathway metabolites—including kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxykynurenine (3−HK), and 3-hydroxyanthranilic acid (3-HANA)—were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The Pediatric Migraine Disability Assessment (PedMIDAS) scores were used to evaluate the functional impact of migraine. Statistical analyses included comparisons between groups and correlation assessments between metabolite levels and clinical parameters. Results: KYN, KYNA, and the KYN/TRP ratio were significantly higher in the migraine group compared to controls (p < 0.05). KYNA/3-HK ratios showed a negative correlation with headache frequency and PedMIDAS scores, whereas 3-HK levels were positively correlated with PedMIDAS scores. Receiver operating characteristic curve analysis identified KYN as a potential biomarker for distinguishing migraine patients from controls, with a sensitivity of 86.7 % and specificity of 45.8 % at a cutoff value of 1415. Conclusion: This study is the first to evaluate kynurenine pathway metabolites in pediatric migraine. The findings suggest that alterations in the tryptophan-kynurenine pathway, particularly increased KYN and KYNA levels, may serve as compensatory mechanisms in migraine pathophysiology. Future studies should explore the therapeutic implications of targeting the kynurenine pathway in pediatric migraine treatment.