Universität zu Köln

Gerlach, D. A., Schopen, K., Linz, P., Johannes, B., Titze, J., Zange, J. and Rittweger, J. (2017). Atrophy of calf muscles by unloading results in an increase of tissue sodium concentration and fat fraction decrease: a Na-23 MRI physiology study. Eur. J. Appl. Physiol., 117 (8). S. 1585 - 1596. NEW YORK: SPRINGER. ISSN 1439-6327

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Abstract

Purpose Na-23 MRI demonstrated increased tissue sodium concentrations in a number of pathologies. Acute atrophy results in muscle fibre volume shrinking that may result in a relative increase of extracellular volume and might affect sodium concentration. Thus, we hypothesized that local unloading of the calf muscles would lead to a decrease in muscle volume and an increase in muscle tissue sodium concentration. Method One lower leg of 12 healthy male subjects was submitted to a 60 day long period of unloading using the Hephaistos orthosis, while the other leg served as control. Na-23 MRI and 2D PD-weighted Dixon turbo spin echo were obtained from the control and orthosis leg using a 3T scanner. For quantification, a sodium reference phantom was used with 10, 20, 30, and 40 mmol/L NaCl solution. Result Tissue sodium concentration (TSC) increased as an effect of unloading in the orthosis leg. Relative increases were 17.4 +/- 16.8% (P = 0.005) in gastrocnemius medialis muscle, 11.1 +/- 12.5 (P = 0.037) in gastrocnemius lateralis muscle, 16.2 +/- 4.7% (P < 0.001) in soleus muscle, 10.0 +/- 10.5% (P = 0.009) in the ventral muscle group, and 10.7 +/- 10.0% (P = 0.003) in the central muscle group, respectively. TSC in the control leg did not significantly change. In the orthosis leg, muscle volume decreased as follows: medial gastrocnemius muscle: -5.4 +/- 8.3% (P = 0.043) and soleus muscle: -7.8 +/- 15.0% (P = 0.043). Conclusion Unloading atrophy is associated with an increase in muscle sodium concentration. Na-23 MRI is capable of detecting these rather small changes.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Gerlach, D. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schopen, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Linz, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Johannes, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Titze, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zange, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rittweger, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-222755
DOI:	10.1007/s00421-017-3647-4
Journal or Publication Title:	Eur. J. Appl. Physiol.
Volume:	117
Number:	8
Page Range:	S. 1585 - 1596
Date:	2017
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1439-6327
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MAGNETIC-RESONANCE; SKELETAL-MUSCLE; MULTIPLE-SCLEROSIS; RELAXATION-TIMES; BED REST; IN-VIVO; 3 TESLA; CARTILAGE; EXERCISE; NMR Multiple languages Physiology; Sport Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22275