Metabolic changes upon supervised aerobic exercise in old adults monitored with 1H MRSI.

Ulrich Pilatus¹, Bianca Lienerth², Katharina Dietz³, Sina Schwarz⁴, Johannes Fleckenstein⁴, Silke Matura³, Tobias Engeroff⁴, Eszter Füzéki⁴, Valentina A. Tesky³, Elke Hattingen¹, Ralf Deichmann², Lutz Vogt⁴, Winfried Banzer⁴, and Johannes Pantel³

¹Neuroradiology, Goethe-Universität Frankfurt, Frankfurt, Germany, ²Brain Imaging Center, Goethe-Universität Frankfurt, Frankfurt, Germany, ³Institute of General Practice, Goethe-Universität Frankfurt, Frankfurt, Germany, ⁴Institute of Sport Sciences, Goethe-Universität Frankfurt, Frankfurt, Germany

Synopsis

In an interventional study changes in metabolic profiles (NAA/tCr, NAA/tCho) upon aerobic exercise were studied comparing two subgroups of volunteers who performed/not-performed supervised aerobic exercise. We observed a difference between both groups which can mainly be assigned to increased NAA/tCho in the group performing exercise.

Introduction

Physical exercise is thought to be beneficial in altering the trajectory of cognitive decline in older adults. Metabolic changes related to physical activity as measured by magnetic resonance spectroscopy (MRS) were already reported [1,2]. Here we present data from a prospective study comparing 1H MRS detectable metabolic profiles of two subgroups of volunteers who performed/not-performed supervised aerobic exercise.

Methods

The data were collected in the framework of a comprehensive study protocol designed to study physical activity and cerebral metabolism in older people [3]. Briefly, participants (healthy adults, age > 65 y) were divided in two subgroups (intervention and control). Only the intervention group commenced supervised aerobic exercise after an initial examination, which included an MRI/MRS protocol. After 12 weeks the examinations were repeated. The ¹H MRSI data were recorded as a transversal slice just above the corpus callosum (240 × 240 mm² FOV, 16 × 16 matrix, 12 mm thickness, circular weighted acquisition scheme with 2 acquisitions at center of k-space, TR 1500 ms, TE 30 ms, total duration 5 min). Metabolite profiles (NAA/tCr, NAA/tCho) were collected from voxels covering a 35 x 35 mm² area in the center of the slice. Spectra were analysed with LCModel. Statistical analysis was performed using ANOVA with repeated measurements.

Results

Figure 1 shows changes in NAA/tCr and NAA/tCho for the intervention group (red, N = 25 ) and the non-active control group (blue, N = 23). ANOVA for repeated measurements revealed statistical significance of p < 0.06 for the multivariate effect (group x repetition) indicating a strong hint for an effect of active training. As shown in Figure 2, the effect can mainly be assigned to an increase in NAA/tCho for the intervention group (p < 0.02) with no change observed for the control group (p < 0.03 for (group x repetition)). While the increase in NAA/tCr was also significant in the intervention group (p < 0.04), the (group x repetition) effect was not significant for this variable (p > 0.51). To evaluate whether these changes were related to a potential change in the GM/WM fraction of the target area, we calculated these fraction from segmented MRI data. As shown in Figure 2, multivariate ANOVA with repeated measurements did not show a difference for the effect (group x repetition) (p > 0.60) while there was a significant change in the GM and WM ratio regarding the repetition (p < 0.03).

Acknowledgements

We thank Horst Michaelis, former Directorat the Cronstetten-Haus, for his patronage.The study has been granted by the Else-Kröner-Fresenius-Stiftung and the Cronstetten-Stiftung.

References

1. Erickson, K. I.; Weinstein, A. M.; Sutton, B. P.; Prakash, R. S.; Voss, M. W.; Chaddock, L.; Szabo, A. N.; Mailey, E. L.; White, S. M.; Wojcicki, T. R.; McAuley, E. & Kramer, A. F. (2012), 'Beyond vascularization: aerobic fitness is associated with N-acetylaspartate and working memory.', Brain Behav 2(1), 32--41.

2. Gonzales, M. M.; Tarumi, T.; Kaur, S.; Nualnim, N.; Fallow, B. A.; Pyron, M.; Tanaka, H. & Haley, A. P. (2013), 'Aerobic fitness and the brain: increased N-acetyl-aspartate and choline concentrations in endurance-trained middle-aged adults.', Brain Topogr 26(1), 126--134.

3. Fleckenstein, J.; Matura, S.; Engeroff, T.; Füzéki, E.; Tesky, V. A.; Pilatus, U.; Hattingen, E.; Deichmann, R.; Vogt, L.; Banzer, W. & Pantel, J. (2015), 'SMART: physical activity and cerebral metabolism in older people: study protocol for a randomised controlled trial.', Trials 16(1), 155.

Figures

Figure 1: Metabolite concentration ratios for the intervention (red) and control (blue) group prior and post 12 weeks of aerobic exercise.

Figure 2: GM and WM fraction in the target regions choosen for evaluation of metabolite profiles prior and post 12 weeks of aerobic exercise.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)

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