Low Concentration of BDNF in the Acute Phase of Ischemic Stroke as a Factor in Poor Prognosis in Terms of Functional Status of Patients

BACKGROUND: According to recent studies, brain-derived neurotrophic factor (BDNF) probably plays a role in development of cerebral ischemia and can be significant for the prognosis of improved mobility after stroke. The aim of this prospective study was to evaluate the blood concentration of BDNF during the 1st day of first-ever ischemic stroke and find a potential association between BDNF concentration and the neurological status in the acute period, as well as between BDNF and the functional status in the sub-acute phase of stroke.
MATERIAL AND METHODS: The prospective study involved 87 patients aged 39–99 years (42 women, 45 men) with first-in-life complete ischemic stroke.
All study subjects underwent analysis as follows: BDNF blood concentration and neurological status according to NIHSS on the 1st day of stroke, comorbidities, etiological type of ischemic stroke by ASCOD, and functional status on the 14th and 90th day after the onset according to mRankin scale.
RESULTS: Mean concentration of BDNF in the study group was 9.96 ng/mL±5.21, median 10.39 ng/mL. Patients aged ≤65 years (25 individuals) had a significantly higher mean concentration of BDNF (11.94 ng/mL±4.46; median 12.34 ng/mL) than the older subjects (62 individuals) with a mean concentration of 9.17 ng/mL±5.32 (median 8.66 ng/mL).
The mean score by mRankin scale on the 90th day was significantly higher among patients with lower concentrations of BDNF on the 1st day of stroke, which reflects their poorer functional status.
The functional status on the 90th day was significantly worse (3–6 points by Rankin scale) in patients who had BDNF below the mean value in the acute phase of stroke.
The independent factors for poor functional status of patients on the 90th day after stroke were a score >4 points by NIHSS (RR 1.14; 95% CI: 1.00–1.31; p=0.027) and the concentration of BDNF below the mean value (assessed on the 1st day of stroke) (RR 14.49; CI 4.60–45.45; p=0.000).
CONCLUSIONS: The neurological status and concentration of BDNF on the 1st day of ischemic stroke are independent prognostic factors in medium-term observation.
Reduction in the concentration of BDNF in the acute phase of stroke is a factor for poor prognosis in terms of the functional status of patients on the 90th day after onset.

Keywords: Acute Disease, Aged, 80 and over, Biomarkers - blood, Brain Ischemia - physiopathology, Brain-Derived Neurotrophic Factor - blood, Prognosis, Prospective Studies, Stroke - physiopathology