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Artificial Gravity: Effects on Bone TurnoverThe impact of microgravity on the human body is a significant concern for space travelers. Since mechanical loading is a main reason for bone loss, artificial gravity might be an effective countermeasure to the effects of microgravity. In a 21-day 6 head-down tilt bed rest (HDBR) pilot study carried out by NASA, USA, the utility of artificial gravity (AG) as a countermeasure to immobilization-induced bone loss was tested. Blood and urine were collected before, during, and after bed rest for bone marker determinations. Bone mineral density was determined by DXA and pQCT before and after bed rest. Urinary excretion of bone resorption markers (n-telopeptide and helical peptide) were increased from pre-bed rest, but there was no difference between the control and the AG group. The same was true for serum c-telopeptide measurements. Bone formation markers were affected by bed rest and artificial gravity. While bone-specific alkaline phosphatase tended to be lower in the AG group during bed rest (p = 0.08), PINP, another bone formation marker, was significantly lower in AG subjects than CN before and during bed rest. PINP was lower during bed rest in both groups. For comparison, artificial gravity combined with ergometric exercise was tested in a 14-day HDBR study carried out in Japan (Iwase et al. J Grav Physiol 2004). In that study, an exercise regime combined with AG was able to significantly mitigate the bed rest-induced increase in the bone resorption marker deoxypyridinoline. While further study is required to more clearly differentiate bone and muscle effects, these initial data demonstrate the potential effectiveness of short-radius, intermittent AG as a countermeasure to the bone deconditioning that occurs during bed rest and spaceflight. Future studies will need to optimize not only the AG prescription (intensity and duration), but will likely need to include the use of exercise or other combined treatments.
Document ID
20070025042
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Heer, M.
(Deutsche Forschungsanstalt fuer Luft- und Raumfahrt Germany)
Zwart, S /R.
(NASA Johnson Space Center Houston, TX, United States)
Baecker, N.
(Deutsche Forschungsanstalt fuer Luft- und Raumfahrt Germany)
Smith, S. M.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 23, 2013
Publication Date
September 13, 2007
Subject Category
Aerospace Medicine
Meeting Information
Meeting: Medicine and Mobility
Location: Cologne
Country: Germany
Start Date: September 13, 2007
End Date: September 15, 2007
Distribution Limits
Public
Copyright
Other

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