Depression and anxiety symptoms are highly prevalent among women during pregnancy and post-partum. Previous studies suggest that one of the pathophysiological underpinnings could be an enhanced metabolism of tryptophan (Trp) into kynurenine (Kyn) due to increased inflammation. However, the longitudinal changes in the Kyn pathway and the complex interplay with inflammation and stress in women with perinatal depressive or anxiety symptoms are incompletely understood. We examined a cohort of healthy women at 34-36 gestational weeks. One hundred and ten women were assessed for salivary cortisol and 97 participants were also assessed for serum levels of Trp, Kyn and interleukin 6 (IL-6). Women filled in two screening questionnaires for depressive (Edinburgh Postnatal Depression Scale (EPDS)) and anxiety (State Trait Anxiety Inventory subscale (STAI-S)) symptoms at 34-36 gestational weeks, delivery, 3 and 12 months postpartum. Unexpectedly, lower prenatal Kyn levels were associated with higher depressive symptoms in late pregnancy. Furthermore, prenatal Trp levels and the Kyn/Trp ratio moderate the association between IL-6 levels and depressive symptoms during the perinatal and the post-partum period. We found no interactions between Trp and Kyn biomarkers and cortisol on depressive symptoms. The observed associations were more robustly found for depressive symptoms, whereas weak and non-significant effects were found for the trajectory of anxiety symptoms. Overall, our data support the involvement of the Trp to Kyn pathway and inflammation in the course of depressive but not anxiety symptoms in women from late pregnancy until one-year post-partum, providing new evidence on the mechanisms regulating emotions during pregnancy and after delivery in a low-risk sample.

中文翻译：

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在低风险样本中，产前 IL-6 水平和色氨酸到犬尿氨酸途径的激活与围产期和产后的抑郁症状相关，但与焦虑症状无关

抑郁和焦虑症状在怀孕期间和产后的女性中非常普遍。先前的研究表明，其中一个病理生理学基础可能是由于炎症增加导致色氨酸 (Trp) 代谢为犬尿氨酸 (Kyn) 的增强。然而，对于有围产期抑郁或焦虑症状的女性，Kyn 通路的纵向变化以及与炎症和压力的复杂相互作用尚不完全清楚。我们在 34-36 孕周检查了一组健康女性。评估了 110 名女性的唾液皮质醇，还评估了 97 名参与者的血清 Trp、Kyn 和白细胞介素 6 (IL-6) 水平。妇女在妊娠 34-36 周、分娩、产后 3 个月和 12 个月时填写了两份关于抑郁症（爱丁堡产后抑郁量表 (EPDS)）和焦虑症（状态特质焦虑量表子量表 (STAI-S)）症状的筛查问卷。出乎意料的是，较低的产前 Kyn 水平与妊娠晚期较高的抑郁症状相关。此外，产前 Trp 水平和 Kyn/Trp 比率调节围产期和产后期间 IL-6 水平与抑郁症状之间的关联。我们发现 Trp 和 Kyn 生物标志物与皮质醇对抑郁症状没有相互作用。观察到的关联更强烈地发现抑郁症状，而发现焦虑症状轨迹的微弱和非显着影响。全面的，