Exploratory metabolomic profiling in migraine with PFO: dysregulated pathways and potential biomarkers

Background: Emerging evidence implicates patent foramen ovale (PFO) as a potential contributor to migraine through paradoxical metabolite shunting, microembolism and hypoxemia. However, systematic characterization of metabolic alterations in migraine patients with PFO (PFO-M) remains unexplored, limiting biomarker discovery and mechanistic insights. This study aimed to delineate metabolomic signatures differentiating PFO-M from healthy controls, with a focus on bridging cardiac structural anomalies with metabolic dysregulation.
Methods: Untargeted metabolomic profiling was performed on plasma from 30 PFO-M patients and 17 age- and sex-matched controls. Validation cohorts from 110 PFO-M and 110 healthy controls were analyzed for indoleacrylic acid (IA) levels using ELISA. 
Findings: Untargeted metabolomic analysis revealed that 211 annotated metabolites (of 4,858 total), 13 human KEGG metabolic pathways (of 48 total), and 61 reactome pathways (of 119 total) were significantly changed in the plasma of PFO-M group, as compared to controls, predominantly involving branched-chain amino acids (BCAAs), neurosteroids, and tryptophan derivatives. Spearman correlation analysis between these differential metabolites and migraine symptom severity scores identified 32 metabolites exhibiting significant associations. Notably, 8 metabolites, including IA, acetyl-L-carnitine (ALC), L-cystine, beta-alanine, L-alanine, phenylalanine, 5 alpha-dihydrotestosterone sulfate and 5 alpha-pregnan-3 beta,20 beta-diol 3-sulfate, exhibited reduced plasma levels in PFO-migraine patients and significant symptom correlations. Arterial-venous correlation analysis revealed concordant reductions in IA and ALC, with arterial levels inversely associated with symptom severity. Sex stratification revealed lower IA and ALC levels in female patients, negatively correlating with symptom severity, while reduced 5 alpha-dihydrotestosterone sulfate and dehydroepiandrosterone sulfate (DHEA-S) showed positive correlations. Aura-specific sub-analysis identified elevated 4-hydroxyproline and decreased 2-hydroxybutyric acid, ketoleucine, N,N-diethylglycine and L-isoleucine as potential biomarkers, alongside sex-dependent neurosteroid alterations and diminished IA and ALC. Furthermore, plasma IA levels were validated and exhibited markedly lower in another PFO-M cohorts. The IA combined with hs-CRP achieved superior diagnostic accuracy, with IA reduction linked to female gender, prior cerebral infarction, and migraine severity.
Interpretation: Initial characterization of metabolic alterations in PFO-comorbid migraine suggests potential involvement of BCAA, neurosteroid, and tryptophan pathway disturbances. IA reduction, reflecting gut-brain axis disregulation and impaired inflammatory modulation, potentially serving as both 
a stratification biomarker and therapeutic target in PFO-M.