Physical exercise to rebalance kynurenine metabolism in borderline personality disorder - Preliminary findings.

Systemic inflammation and dysregulated kynurenine (KYN) metabolism are increasingly recognised as key factors in various psychiatric disorders. Imbalances in the KYN pathway are associated with psychological and cognitive symptoms across disorders like depression and schizophrenia, yet remain unexplored in borderline personality disorder (BPD). This study is the first to compare KYN metabolism together with the myokine IL-6 in BPD patients and healthy controls and to examine acute exercise effects on this pathway in BPD. Fourteen patients with BPD and nine controls participated in two experimental conditions: cycling exercise and a control session. Serum samples were analysed for tryptophan (TRP), KYN, kynurenic acid (KA), and quinolinic acid (QA). Results revealed greater QA/KYN and lower KA/KYN and KA/QA ratios in BPD, indicating a shift toward the neurotoxic branch. Acute exercise increased KA, KA/KYN, KA/QA, and IL-6 levels, highlighting its potential to enhance neuroprotective KYN activity. These findings suggest KYN pathway dysregulation in BPD and support physical exercise as a promising intervention to rebalance this pathway. Further research should investigate long-term exercise effects and their impact on psychological outcomes in BPD.