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Dynamics of markers for neuronal plasticity (BDNF, IGF-1, IGFBP-3) and general fitness during a six-month intervention study in healthy older adults (AKTIV study)


Poppa,  Caroline
Center for Lifespan Psychology, Max Planck Institute for Human Development, Max Planck Society;

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Poppa, C. (2022). Dynamics of markers for neuronal plasticity (BDNF, IGF-1, IGFBP-3) and general fitness during a six-month intervention study in healthy older adults (AKTIV study). Master Thesis, Freie Universität Berlin.

Cite as: https://hdl.handle.net/21.11116/0000-000A-9511-A
Despite healthy aging being associated with brain atrophy and declines in overall cognitive
function, past research has highlighted the beneficial effect of greater fitness on brain
morphology and cognition, especially in older age. On the other hand, markers for neuronal
plasticity, as IGF-1, IGFBP-3, and BDNF namely, have experienced a rise in attention when
investigating the brain’s ability to induce structural and behavioural changes over the
lifespan. In this thesis, dynamics of serum-derived markers for neuronal plasticity (IGF-1,
IGFBP-3, BDNF) and general fitness (VO₂ and power at peak, BMI and body fat percentage)
were investigated in a sample of healthy older adults (N = 141; 63-78 years) at pre-intervention
and after six months of aerobic exercise (AE) (SP group, N = 71; 52.1% women) versus no AE
intervention (AC group, N = 70; 50.0% women), with special regards to differences between
male and female participants.
Analysis of variance revealed a significant effect of sex on IGFBP-3 levels at pre-intervention
(T1) with women showing both significantly higher baseline and post-AE levels. In contrast
to previous reports, no sex differences in baseline IGF-1 levels as well as no transient increases
in BDNF levels after AE were found at T1. Body fat percentage, VO₂ and power at peak
showed sex-specificity with physical fitness markers being higher in men than women, while
mean body fat percentage was significantly higher in the female sample. Bonferroni corrected
correlational analysis between markers at pre-intervention (pB<.0083) showed that baseline
and post-AE IGF-1 levels correlated with physical fitness markers in men but not women.
After six months of AE-intervention, baseline IGFBP-3 levels in the control group had
significantly decreased from T1 to T3 in comparison to the SP group. Within the SP group,
women displayed stronger increases in physical fitness markers than men. Further, SP women
significantly decreased their body fat percentage and BMI over the course of the study,
whereas SP men displayed no relevant changes in their descriptive body measures over time.
Bonferroni corrected (pB<.0125) post-intervention (T3) analysis revealed a significant inverse
relation between post-AE IGFBP-3 levels and peak power in SP women (N = 35) when
compared to the same sex control (N = 31), but not in men.
In sum, this work shows significant sex differences in dynamics of IGF-system markers (both
at baseline and after exhaustive AE) and fitness in healthy older adults. In particular, IGFsystem
markers displayed sex-specificity with baseline and transient AE-induced IGFBP-3
changes in women being higher than in men. Further, women within the SP group increased
significantly in VO₂ peak and power at peak when compared to the same sex control.
Importantly, six months of AE resulted in higher baseline IGFBP-3 levels when compared to
the control that decreased significantly in their baseline IGFBP-3 levels from T1 to T3. Overall,
dynamics between IGF-system markers and fitness measures showed sex differences and
were altered after a six-month AE intervention, challenging the dogma of little physiological
plasticity in aged bodies and indicating the pressing need to further investigate the effect of
biological sex on markers for neuronal plasticity throughout the lifespan.