Alterations of Blood Plasma Metabolites, Including Kynurenine and Tryptophan, in Bipolar Disorder.

BACKGROUND

Bipolar disorder (BD) is a psychiatric disorder characterized by recurrent episodes of mania and depression. However, the pathophysiology has not yet been fully elucidated.

METHODS

In this study, we employed capillary electrophoresis time-of-flight mass spectrometry to measure 34 plasma metabolites and compared the levels between individuals with BD (N = 64, male/female = 30/34, age [mean ± S.D.] = 51.4 ± 12.0 years) and non-psychiatric controls (N = 92, male/female = 32/60, age = 38.6 ± 13.4 years).

RESULTS

Significant differences in 12 plasma metabolites, including kynurenine and tryptophan, were observed between the two groups (q < 0.05).

DISCUSSION: These findings support the involvement of amino acid dysregulation in the pathophysiology of BD. However, the cross-sectional design, lack of control for medication, diet, and smoking, and the use of peripheral rather than central samples limit the generalizability of the results. Further longitudinal and mechanistic studies are needed. Integration with clinical, imaging, and genetic data in future research may facilitate the development of metabolomics-based biomarkers.