FROM SPACE FLIGHTS TO OSTEOPOROSIS
Abstract
Space missions (microgravity) alter the balance between bone formation/resorption and induce bone loss. This effect represents a major limiting step in the realization of long-term space missions. A similar picture is induced by prolonged immobilization at bed (bed rest). The Osteoporosis and Muscular Atrophy project (OSMA) was a research program sponsored by the Italian Space Agency which included 35-day bed rest experiments in healthy young men. Anthropometric data of these experiments indicated the expected bone mass reduction in some segments of the leg and body weight redistribution from non-fat mass to fat mass. According to the current view, the bone mass reduction due to microgravity/bed rest is associated with the release of calcium from the bone into the bloodstream (hypercalcemia) which, in turn, lowers the secretion of parathyroid hormone and increases urinary calcium excretion. One of the main unsolved points in this view is that hypercalcemia is mild and transient during microgravity/bed rest whereas parathyroid hormone reduction is sustained. The analyses of the OSMA bed-rest will focus on the possible differences between early changes and later changes in indices of calcium homeostasis and bone metabolism during bed rest. The research on the mechanisms underlying bone mass loss during microgravity/ bed rest could be of help not only to space medicine but hopefully also for prevention and control of bone ageing and osteoporosis.References
Biolo G., Agostini F., Šimunič B., Sturma M., Torelli L., Preiser J.C., Deby-Dupont G., Magni P., Strollo F., Di Prampero P., Guarnieri G., Mekjavič I.B., Pišot R., Narici M.V. (2008). Positive energy balance is associated with accelerated muscle atrophy and increased erythrocyte glutathione turnover during 5 wk of bed rest, American Journal of Clinical Nutrition. Oct; 88(4):950-8.
Drummer C., Valenti G., Cirillo M., Perna A., Bellini L., Nenov V., De Santo N.G. (2002). Vasopressin, hypercalciuria and aquaporin - the key elements for impaired renal water handling in astronauts? Nephron. 92(3):503-14. Review.
Firestein Gary S., Budd Ralph C., Harris Edward D. jr., McInnes Iain B., Ruddy S., Sergent John S. (2008). Kelly’s “Textbook of Rheumatology” (8th edition), Saunders Elsevier.
LeBlanc A., Schneider V., Spector E., Evans H., Rowe R., Lane H., Demers L., Lipton A. (1995). Calcium absorption, endogenous excretion, and endocrine changes during and after long-term bed rest. Bone, 16(4 Suppl.):301S-304S.
LeBlanc A.D., Spector E.R., Evans H.J., Sibonga J.D. (2007). Skeletal responses to space flight and the bed rest analog: a review. Journal of Musculoskeletal and Neuronal Interactions. Jan-Mar; 7(1):33-47.
Lueken S.A., Arnaud S.B., Taylor A.K., Baylink D.J. (1993). Changes in markers of bone formation and resorption in a bed rest model of weightlessness. Journal of Bone and Mineral Research. Dec; 8(12):1433-8.
Potts J.T. (2005). Diseases of the parathyroid gland and other hyper- and hypocalcemic disorders. Harrison’s Principles of Internal Medicine (16th edition). McGraw-Hill. New York, pp 2249-2268.
Rittweger J., Šimunič B., Bilancio G., De Santo N.G., Cirillo M., Biolo G., Pišot R., Eiken O., Mekjavič I.B., Narici M. (2009). Bone loss in the lower leg during 35 days of bed rest is predominantly from the cortical compartment. Bone, 44:612-618.
Smith S.M., Heer M. (2002). Calcium and bone metabolism during space flight. Nutrition, 18:849-852.
Smith S.M., Davis-Street J.E., Fesperman J.V., Calkins D.S., Bawa M., Macias B.R., Meyer R.S., Hargens A.R. (2003). Evaluation of treadmill exercise in a lower body negative pressure chamber as a countermeasure for weightlessness-induced bone loss: a bed rest study with identical twins. Journal of Bone and Mineral Research, Dec; 18(12):2223-30.
Stewart A.F., Adler M., Byers C.M., Segre G.V., Broadus A.E. (1982). Calcium homeostasis in immobilization: an example of resorptive hypercalciuria. New England Journal of Medicine. May 13; 306(19):1136-40.
Zerwekh J.E., Ruml L.A., Gottschalk F., Pak C.Y. (1998). The effects of twelve weeks of bed rest on bone histology, biochemical markers of bone turnover, and calcium homeostasis in eleven normal subjects. Journal of Bone and Mineral Research, 13:1594-601.
Downloads
How to Cite
Issue
Section
License
Open Access Policy and Copyright
This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under the terms of the Creative Commons Attribution license (CC BY) that allows others to share the work with an acknowledgement of the work’s authorship and initial publication in this journal.
- Authors grant the publisher commercial rights to produce hardcopy volumes of the journal for sale to libraries and individuals.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal’s published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.