Mechanical Factors and Bone Health: Effects of Weightlessness and Neurologic Injury
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Bone is a dynamic tissue with homeostasis governed by many factors. Among them, mechanical stimuli appear to be particularly critical for bone structure and strength. With removal of mechanical stimuli, a profound bone loss occurs, as best observed in the extreme examples following exposure to space flight or neurologic impairment. This review provides an overview of the changes in bone density and structure that occur during and after space flight as well as following neurologic injury from stroke and spinal cord injury. It also discusses the potential mechanisms through which mechanical stimuli are postulated to act on bone tissue.
KeywordsBone density Weightlessness Space Flight Spinal cord injury Stroke Mechanical stimuli
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- 1.Wolff J: The Law of Bone Remodeling [in German]. Berlin, Germany: Springer; 1986.Google Scholar
- 4.Burger EH, Klein-Nulend J: Mechanotransduction in bone—role of the lacuno-canalicular network. FASEB J 1999, 13(Suppl):S101–S112.Google Scholar
- 15.•• Keyak JH, Koyama AK, LeBlanc A, et al.: Reduction in proximal femoral strength due to long-duration spaceflight. Bone 2009, 44:449–453. This was the first study that examined proximal femur strength estimated by finite element analyses following long-duration microgravity exposure and that identified that the observed bone strength loss is greater than bone density loss.CrossRefPubMedGoogle Scholar
- 27.Greenleaf JE: Physiology of Prolonged Bed Rest [technical memorandum]. Washington, DC: NASA; 1988.Google Scholar