Decreased serum brain-derived neurotrophic factor (BDNF) is associated with post-stroke depression but not with BDNF gene Val66Met polymorphism

Background: Decreased brain-derived neurotrophic factor (BDNF) has been demonstrated in animal models and patients with depression. However, little is known about changes in BDNF in post-stroke depression (PSD). This study investigated the changes in serum BDNF in patients with PSD, and evaluated whether serum concentrations of BDNF were associated with BDNF gene Val66Met polymorphism. Methods: PSD patients were diagnosed in accordance with DSM-IV criteria, and the severity of depression was evaluated with the Hamilton Rating Scale for depression. Serum BDNF was measured twice, first at 7 days after the onset of stroke and then at 3-6 months after stroke. Val66Met polymorphisms of the BDNF gene were determined using the polymerase chain reaction-restriction fragment length polymorphism method. BDNF concentrations and Val66Met polymorphisms were also measured in 30 healthly controls. Results: A total of 93 patients admitted as a result of first time acute ischemic stroke were included. During the 6-month follow-up, 35 patients (37.6%) were diagnosed with PSD. Serum BDNF concentrations were decreased in PSD patients at 3-6 months after stroke (p < 0.05). The serum BDNF concentrations were not associated with BDNF gene Val66Met polymorphisms in either patients or healthy controls. Conclusions: Serum concentrations of BDNF decrease in PSD patients and BDNF may play an important role in the pathogenesis of PSD. However, Val66Met polymorphisms are not associated with serum concentrations of BDNF. The mechanism of decreased serum BDNF requires further study.