Universität zu Köln

Salvadego, Desy, Keramidas, Michail E., Brocca, Lorenza, Domenis, Rossana, Mavelli, Irene, Rittweger, Joern, Eiken, Ola, Mekjavic, Igor B. and Grassi, Bruno (2016). Separate and combined effects of a 10-d exposure to hypoxia and inactivity on oxidative function in vivo and mitochondrial respiration ex vivo in humans. J. Appl. Physiol., 121 (1). S. 154 - 164. BETHESDA: AMER PHYSIOLOGICAL SOC. ISSN 1522-1601

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Abstract

An integrative evaluation of oxidative metabolism was carried out in 9 healthy young men (age, 24.1 +/- 1.7 yr mean +/- SD) before (CTRL) and after a 10-day horizontal bed rest carried out in normoxia (N-BR) or hypoxia (H-BR, FIO2 = 0.147). H-BR was designed to simulate planetary habitats. Pulmonary O-2 uptake ((V) over dotO(2)) and vastus lateralis fractional O-2 extraction (changes in deoxygenated hemoglobin + myoglobin concentration, Delta[deoxy(Hb + Mb)] evaluated using near-infrared spectroscopy) were evaluated in normoxia and during an incremental cycle ergometer (CE) and one-leg knee extension (KE) exercise (aimed at reducing cardiovascular constraints to oxidative function). Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers. During CE (V) over dotO(2peak) and Delta[deoxy(Hb + Mb)] peak were lower (P < 0.05) after both N-BR and H-BR than during CTRL; during KE the variables were lower after N-BR but not after H-BR. During CE the overshoot of Delta[deoxy(Hb + Mb)] during constant work rate exercise was greater in N-BR and H-BR than CTRL, whereas during KE a significant difference vs. CTRL was observed only after N-BR. Maximal mitochondrial respiration determined ex vivo was not affected by either intervention. In N-BR, a significant impairment of oxidative metabolism occurred downstream of central cardiovascular O-2 delivery and upstream of mitochondrial function, possibly at the level of the intramuscular matching between O-2 supply and utilization and peripheral O-2 diffusion. Superposition of hypoxia on bed rest did not aggravate, and partially reversed, the impairment of muscle oxidative function in vivo induced by bed rest. The effects of longer exposures will have to be determined.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Salvadego, Desy UNSPECIFIED UNSPECIFIED UNSPECIFIED Keramidas, Michail E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Brocca, Lorenza UNSPECIFIED UNSPECIFIED UNSPECIFIED Domenis, Rossana UNSPECIFIED UNSPECIFIED UNSPECIFIED Mavelli, Irene UNSPECIFIED UNSPECIFIED UNSPECIFIED Rittweger, Joern UNSPECIFIED UNSPECIFIED UNSPECIFIED Eiken, Ola UNSPECIFIED UNSPECIFIED UNSPECIFIED Mekjavic, Igor B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Grassi, Bruno UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-271549
DOI:	10.1152/japplphysiol.00832.2015
Journal or Publication Title:	J. Appl. Physiol.
Volume:	121
Number:	1
Page Range:	S. 154 - 164
Date:	2016
Publisher:	AMER PHYSIOLOGICAL SOC
Place of Publication:	BETHESDA
ISSN:	1522-1601
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language NEAR-INFRARED SPECTROSCOPY; MUSCLE BLOOD-FLOW; HUMAN SKELETAL-MUSCLE; HEAVY-INTENSITY EXERCISE; OXYGEN-UPTAKE KINETICS; HIGH-ALTITUDE; BED REST; KNEE EXTENSION; HEART-FAILURE; METABOLISM Multiple languages Physiology; Sport Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27154