1. Reduced peripheral availability of tryptophan and increased activation of the kynurenine pathway and cortisol correlate with major depression and suicide.
- Author
-
Messaoud, Amel, Mensi, Rym, Douki, Wahiba, Neffati, Fadoua, Najjar, Mohamed Fadhel, Gobbi, Gabriella, Valtorta, Flavia, Gaha, Lotfi, and Comai, Stefano
- Subjects
TRYPTOPHAN ,MENTAL depression ,SUICIDE ,HYDROCORTISONE ,SUICIDAL ideation - Abstract
Objectives: Patients affected by major depression (MDD) are at high risk of suicide. The metabolism of tryptophan (Trp) along the serotonin (5-HT) and kynurenine (Kyn) pathways was found dysfunctional in MDD and in suicide. However, a clear biological framework linking dysfunctions in Trp metabolism via 5-HT and Kyn, cortisol, and the activities of tryptophan and indoleamino 2,3-dioxygenase (TDO, IDO) enzymes has not been yet clarified in MDD with or without suicidal behaviours. Methods: We analysed peripheral markers of Trp via 5-HT and Kyn pathways, Kyn/Trp ratio as a measure of TDO/IDO activities, cortisol, and psychopathology in 73 non-suicidal and 56 suicidal MDD patients, and in 40 healthy controls. Results: Plasma Trp levels were lower and the ratio Kyn/Trp higher in suicidal MDD than in non-suicidal MDD patients and controls. Trp levels and the ratio Kyn/Trp correlated with suicidal ideation, and cortisol with the Kyn/Trp ratio. Finally, Trp levels discriminated controls from non-suicidal and suicidal MDD patients, and also non-suicidal from suicidal MDD patients. Conclusions: Reduced availability of Trp for 5-HT synthesis and increased activation of the Kyn pathway and cortisol correlate with depression and suicide. Low plasma Trp levels may be a biomarker of MDD and suicide in MDD. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF