Universität zu Köln

Debevec, Tadej ORCID: 0000-0001-7053-3978, Ganse, Bergita ORCID: 0000-0002-9512-2910, Mittag, Uwe, Eiken, Ola, Mekjavic, Igor B. and Rittweger, Joern (2018). Hypoxia Aggravates Inactivity-Related Muscle Wasting. Front. Physiol., 9. LAUSANNE: FRONTIERS MEDIA SA. ISSN 1664-042X

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Abstract

Poor musculoskeletal state is commonly observed in numerous clinical populations such as chronic obstructive pulmonary disease (COPD) and heart failure patients. It, however, remains unresolved whether systemic hypoxemia, typically associated with such clinical conditions, directly contributes to muscle deterioration. We aimed to experimentally elucidate the effects of systemic environmental hypoxia upon inactivity-related muscle wasting. For this purpose, fourteen healthy, male participants underwent three 21-day long interventions in a randomized, cross-over designed manner: (i) bed rest in normoxia (NBR; PiO2 = 133.1 +/- 0.3 mmHg), (ii) bed rest in normobanc hypoxia (HBR; PiO2 = 90.0 +/- 0.4 mmHg) and ambulatory confinement in normobanc hypoxia (HAmb; PiO2 = 90.0 +/- 0.4 mmHg), Peripheral quantitative computed tomography and vastus lateralis muscle biopsies were performed before and after the interventions to obtain thigh and calf muscle cross-sectional areas and muscle fiber phenotype changes, respectively. A significant reduction of thigh muscle size following NBR (-6.9%, SE 0.8%; P < 0.001) was further aggravated following HBR (-9.7%, SE 1.2%; P = 0.027). Bed rest-induced muscle wasting in the calf was, by contrast, not exacerbated by hypoxic conditions (P = 0.47). Reductions in both thigh (-2.7%, SE 1.1%, P = 0.017) and calf (-3.3%, SE 0.7%, P < 0.001) muscle size were noted following HAmb. A significant and comparable increase in type 2x fiber percentage of the vastus lateralis muscle was noted following both bed rest interventions (NBR = +3.1%, SE 2.6%, HBR = +3,9%, SE 2.7%, P < 0.05). Collectively, these data indicate that hypoxia can exacerbate inactivity-related muscle wasting in healthy active participants and moreover suggest that the combination of both, hypoxemia and lack of activity, as seen in COPD patients, might be particularly harmful for muscle tissue.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Debevec, Tadej UNSPECIFIED orcid.org/0000-0001-7053-3978 UNSPECIFIED Ganse, Bergita UNSPECIFIED orcid.org/0000-0002-9512-2910 UNSPECIFIED Mittag, Uwe UNSPECIFIED UNSPECIFIED UNSPECIFIED Eiken, Ola UNSPECIFIED UNSPECIFIED UNSPECIFIED Mekjavic, Igor B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rittweger, Joern UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-186415
DOI:	10.3389/fphys.2018.00494
Journal or Publication Title:	Front. Physiol.
Volume:	9
Date:	2018
Publisher:	FRONTIERS MEDIA SA
Place of Publication:	LAUSANNE
ISSN:	1664-042X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HUMAN SKELETAL-MUSCLE; OBSTRUCTIVE PULMONARY-DISEASE; BODY-MASS INDEX; BED-REST; PROTEIN-SYNTHESIS; RESISTANCE EXERCISE; NORMOBARIC HYPOXIA; OXIDATIVE STRESS; DOWN-REGULATION; WHOLE-BODY Multiple languages Physiology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/18641