The influence of moderate physical activity on the concentration of particular fractions of brain-derived neurotrophic factor in the blood serum of patients with Alzheimer’s disease

Objectives
To determine the influence of moderate physical activity (PA) on the changes in the BDNF (brain-derived neurotrophic factor) and mBDNF (mature BDNF) concentrations in the plasma of patients with Alzheimer’s disease (AD).

Material and methods
The study included 32 people diagnosed with AD of mild or moderate severity, previously not physically active, 16 of whom started training Nordic walking. The BDNF and mBDNF levels were determined before and after the 3-month study. Psychometric measurements were also carried out using the MoCA (Montreal Cognitive Assessment) and ADL (Activities of Daily Living) scales.

Results
During the observation period in the entire study group (32 people) and in the group with MMSE (Mini-Mental State Examination) with scores of 19–23 points (15 people), a significant increase in the serum BDNF concentration was found. In the group of people with the late-onset disease (N = 27), a significant increase in the serum BDNF concentration was found, regardless of PA and a significant increase in the mBDNF concentration only in the active group. There were no significant correlations between changes in the BDNF and mBDNF levels and the general functioning and cognitive performance measured on the MoCA and ADL scales.

Conclusions
The obtained results indicate the possibility of an increase in the BDNF concentration in the serum of patients with Alzheimer’s disease, which is not always related to physical activity and does not correlate with general functioning and cognitive performance. On the other hand, mBDNF may be a more sensitive indicator of the influence of AF on changes in the concentration of neurotrophins than BDNF.