Association between BDNF-196 G>A and BDNF-270 C>T polymorphisms, BDNF concentration, and rTMS-supported long-term rehabilitation outcome after ischemic stroke.

Background: The efficacy of rehabilitation in ischemic stroke patients likely varies because of brain plasticity. One of the main neurotrophins in the central nervous system is brain-derived neurotrophic factor (BDNF).

Objectives: This study aimed to determine allelic and genotypic distribution of BDNF-196 G>A and -270 C>T polymorphisms, and to assess the impact of repetitive transcranial magnetic stimulation (rTMS) on serum BDNF concentrations measured before rehabilitation, after the first 6 h of rehabilitation, and after 3 weeks of rehabilitation.

Methods: Twenty-six patients with hand paresis and 20 with aphasia were randomly assigned to treatment with rTMS or sham stimulation (placebo group).

Results: In men with aphasia, after the first 6 h of rTMS-supported rehabilitation, BDNF concentration was lower among rTMS-treated patients than placebo-treated patients. A similar difference was observed in women with aphasia after 3 weeks of rTMS-supported rehabilitation. No significant differences in serum BDNF concentration were observed in patients with different BDNF-196 G>A or -270 C>T genotypes. During the observation period, BDNF concentration did not differ significantly between patients who improved and those who did not.

Discussion: One possible explanation for the observed difference between rTMS-stimulated and sham-stimulated patients is the suppression of BDNF production by rTMS in the healthy brain hemisphere.