[Correlation between kynurenine metabolites and postpartum depression]

To explore the correlation between kynurenine (KYN) metabolites and postpartum depression (PPD), and to provide new possible explanation for the pathogenesis of postpartum depression (PPD).
 Methods: A total of 726 Chinese women, who received cesarean section, were enrolled in this study. PPD was diagnosed with an Edinburgh Postnatal Depression Scale (EPDS) score ≥13. Twenty-four women with PPD and 48 matched women without PPD were randomly selected. The perinatal serum concentrations of KYN, quinolinic acid (QUIN) and kynurenic acid (KYNA) were measured. Subsequently, the puerperants were compared for the differences in the serum concentrations of KYN, QUIN and KYNA at the end of term, day 1 and day 3 after cesarean section, respectively.
 Results: The incidence of PPD was 7.99%. Of clinical characteristics, pressure during pregnancy was significantly different between subjects with or without PPD (P<0.01). Patients with PPD showed significantly increased serum KYN concentration (P<0.05) at the end of term, increased serum QUIN concentration (P<0.05) and decreased KYNA concentration (P<0.05) on the third day after cesarean section as compared with the control women. Furthermore, the KYNA/QUIN ratio was significantly higher in patients with PPD as compared to the control women on the third day after cesarean section (P<0.01).
 Conclusion: The contribution of alterations in plasma levels of KYN, QUIN and KYNA is closely related with the incidence of PPD, and correction of KYNA/QUIN ratio could be a new strategy for the prevention and treatment of postpartum depressive symptoms.