Abnormal Serum BDNF and p-mTOR in MDD in Adolescents with Childhood Trauma

Adolescents with major depressive (MDD) episodes associated with childhood trauma have a poorer response to treatment and a higher risk of suicide. The underlying etiology is unclear. Brain-derived neurotrophic factor (BDNF) could improve depressive symptoms by down-regulating mammalian target of rapamycin (mTOR) signaling pathways, which was involved in adverse environmental stimuli during neurodevelopment. BDNF and mTOR have not been reported simultaneously in adolescents with major depressive episodes associated with childhood trauma.

Childhood Trauma Questionnaire-Short Form (CTQ-SF), Children's Depression Inventory (CDI) and Children's Depression Rating Scale-Revised (CDRS-R) were used to evaluate the recruited adolescents with major depression episodes. Serum BDNF and p-mTOR levels were measured by ELISA in 31 adolescents with major depression episodes with childhood trauma and 18 matched healthy control.

The serum levels of BDNF were significantly lower (p<0.001); and the serum levels of p-mTOR were high (p=0.003) in the adolescents with the first episode of major depressive episode accompanied by childhood trauma. Of the 31 adolescents with major depressive episodes, 17 had suicide or self-injury. Compared with the healthy control group, the serum levels of BDNF in patients with suicide or self-injury were lower than those without suicide or self-injury(p<0.001); the serum levels of p-mTOR were higher than those without suicide or self-injury (p=0.01). While in patients without suicide or self-injury, only serum p-mTOR was significantly higher than that in healthy group (p=0.028). BDNF was negatively correlated with CDRS-R (r=-0.427, p=0.006), p-mTOR was positively correlated with CDI (r=0.364, p=0.048). According to Receiver Operating Characteristic Curve (ROC), the combination of serum BDNF and p-mTOR levels have better diagnostic value.

Neurotrophic and signaling pathways, involving BDNF and p-mTOR, may play a role in adolescent MDD with a history of childhood trauma, especially patients with suicide and self-injury tendencies.