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Titel: Capillary rarefaction during bed rest is proportionally less than fibre atrophy and loss of oxidative capacity
VerfasserIn: Hendrickse, Paul William
Wüst, Rob C. I.
Ganse, Bergita
Giakoumaki, Ifigeneia
Rittweger, Jörn
Bosutti, Alessandra
Degens, Hans
Sprache: Englisch
Titel: Journal of Cachexia, Sarcopenia and Muscle
Bandnummer: 13
Heft: 6
Seiten: 2712-2723
Verlag/Plattform: Wiley
Erscheinungsjahr: 2022
Freie Schlagwörter: Bed rest
Atrophy
Skeletal muscle
Artificial gravity
Capillarization
Oxidative capacity
DDC-Sachgruppe: 610 Medizin, Gesundheit
Dokumenttyp: Journalartikel / Zeitschriftenartikel
Abstract: Background Muscle disuse from bed rest or spaceflight results in losses in muscle mass, strength and oxidative capacity. Capillary rarefaction may contribute to muscle atrophy and the reduction in oxidative capacity during bed rest. Artificial gravity may attenuate the negative effects of long-term space missions or bed rest. The aim of the present study was to assess (1) the effects of bed rest on muscle fibre size, fibre type composition, capillarization and oxidative capacity in the vastus lateralis and soleus muscles after 6 and 55 days of bed rest and (2) the effectiveness of artificial gravity in mitigating bed-rest-induced detriments to these parameters. Methods Nineteen participants were assigned to a control group (control, n = 6) or an intervention group undergoing 30 min of centrifugation (n = 13). All underwent 55 days of head-down tilt bed rest. Vastus lateralis and soleus biopsies were taken at baseline and after 6 and 55 days of bed rest. Fibre type composition, fibre cross-sectional area, capillarization indices and oxidative capacity were determined. Results After just 6 days of bed rest, fibre atrophy ( 23.2 ± 12.4%, P < 0.001) and reductions in capillary-to-fibre ratio (C:F; 1.97 ± 0.57 vs. 1.56 ± 0.41, P < 0.001) were proportional in both muscles as reflected by a maintained capillary density. Fibre atrophy proceeded at a much slower rate between 6 and 55 days of bed rest ( 11.6 ± 12.1% of 6 days, P = 0.032) and was accompanied by a 19.1% reduction in succinate dehydrogenase stain optical density (P < 0.001), without any further significant decrements in C:F (1.56 ± 0.41 vs. 1.49 ± 0.37, P = 0.459). Consequently, after 55 days of bed rest, the capillary supply–oxidative capacity ratio of a fibre had increased by 41.9% (P < 0.001), indicating a capillarization in relative excess of oxidative capacity. Even though the heterogeneity of capillary spacing (LogRSD) was increased after 55 days by 12.7% (P = 0.004), tissue oxygenation at maximal oxygen consumption of the fibres was improved after 55 days bed rest. Daily centrifugation failed to blunt the bed-rest-induced reductions in fibre size and oxidative capacity and capillary rarefaction. Conclusions The relationship between fibre size and oxidative capacity with the capillary supply of a fibre is uncoupled during prolonged bed rest as reflected by a rapid loss of muscle mass and capillaries, followed at later stages by a more than proportional loss of mitochondria without further capillary loss. The resulting excessive capillary supply of the muscle after prolonged bed rest is advantageous for the delivery of substrates needed for subsequent muscle recovery.
DOI der Erstveröffentlichung: 10.1002/jcsm.13072
URL der Erstveröffentlichung: https://onlinelibrary.wiley.com/doi/10.1002/jcsm.13072
Link zu diesem Datensatz: urn:nbn:de:bsz:291--ds-392058
hdl:20.500.11880/35334
http://dx.doi.org/10.22028/D291-39205
ISSN: 2190-6009
2190-5991
Datum des Eintrags: 3-Mär-2023
Fakultät: M - Medizinische Fakultät
Fachrichtung: M - Chirurgie
Professur: M - Prof. Dr. med. Bergita Ganse
Sammlung:SciDok - Der Wissenschaftsserver der Universität des Saarlandes



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