Impact of BDNF -196 G>A and BDNF -270 C>T polymorphisms on stroke rehabilitation outcome: sex and age differences.

Background: Genetic factors, including gene polymorphisms, are promising in determining stroke rehabilitation outcome. Brain-derived neurotrophic factor (BDNF) is one of the most attractive because of its role in neuroplasticity and brain repair.

Objective: The aim of present study was to assess the role of BDNF -196 G≯A (val66met) and -270 C≯T on clinical parameters and functional outcome in patients with ischemic and hemorrhagic stroke. Additional analyses according to sex and age (≤55 and ≯55 years) were performed.

Methods: Three hundred thirty-eight patients (287 with ischemic and 51 with hemorrhagic stroke) were evaluated in terms of neurological deficit (National Institute of Heath Stroke Scale [NIHSS]), activities of daily living (Barthel Index [BI]), and everyday functionality (Rankin score [RS]) before and after rehabilitation. BDNF polymorphism genotyping was performed by polymerase chain reaction restriction fragment length polymorphism analysis.

Results: In multivariative analysis, unfavorable outcome of stroke rehabilitation (RS ≥2) was associated with independent factors: ischemic stroke (odds ratio [OR], 2.59; 95% CI, 1.03-6.47), female gender (OR, 2.80; 95% CI, 1.39-5.64), depression (OR, 4.24; 95% CI, 1.45-12.35), falls (OR, 2.61; 95% CI, 1.16-5.87), and BDNF -196 GG polymorphism (OR, 2.18; 95% CI, 1.09-4.35). The differences of functional parameters measured with BI and RS on admission and at discharge are apparent only for comparisons between patients ≤55 and ≯55 years old carrying BDNF -196 GA+AA genotypes but not in those carrying -196 GG genotype; the differences were evident in women but not in men.

Conclusions: BDNF -196 G≯A polymorphism might affect functional outcome of stroke rehabilitation, but this hypothesis needs further verification.