Brain derived neurotrophic factor (BDNF) is a member of neurotrophin family implied in brain resistance to insults. Murine studies demonstrated increased hippocampal concentration after acute, and decreased after chronic immobilization. In humans, chronic stress and sedentary lifestyle decreased plasmatic BDNF, while there is no data regarding acute immobilization. The aim of our study was to evaluate age-related responses (comparing 7 YOUNG 23 ± 3 years and 8 OLDER subjects 60 ± 4 years) of plasma BDNF before (BDC) and after (BR14) 14 days of horizontal bed rest (BR). At BDC, BDNF levels were not different between the two groups (p=0.101), while at BR14 BDNF levels were higher in OLDER (62.02±18.31 vs YOUNG: 34.36±15.24 pg/ml, p=0.002). A GLM for repeated measures showed a significant effect of BR on BDNF (p=0.002). The BDC BDNF levels correlated with fat-free mass in the whole population (ALL) (R=0.628, p=0.012), OLDER (R=0.753, p=0.031), and YOUNG (R=0.772, p=0.042), and with total cholesterol in ALL (R=0.647, p=0.009) and OLDER (R=0.805, p=0.016). At BR14 BDNF correlated with total cholesterol (R=0.579, p=0.024) and age (R=0.647, p=0.009) in ALL. With the increase of age, the brain could become naturally less resistant to acute stressors, including the detrimental effects of prolonged bed rest, and thus, the increase in BDNF only in older group might reflect a protective overshooting of the brain to counteract negative effects in such conditions.
- brain derived neurotrophic factor
- bed rest
- acute stress
- aging brain
- Copyright © 2016, Journal of Applied Physiology