Bone Metabolism and Vascular Health in Individuals with Spinal Cord Injury: Implications for Prolonged Space Flight
- Paper number
IAC-08.A1.2.15
- Author
Ms. Jessica Scott, University of British Columbia, Canada
- Year
2008
- Abstract
Background: Exposure to the microgravity environment results in many musculoskeletal and cardiovascular alterations. Weightlessness during space flight has been shown to increase bone resorption and decrease bone formation, parameters which NASA has identified as key barriers to successful long-term space flight. Similarly, the NASA Bioastronautics Critical Path Roadmap (2005) identified serious cardiac dysrhythmias and diminished cardiac and vascular function as the primary cardiovascular risks of spaceflight. Until recently, researchers studying general populations have viewed commonly occurring age-related conditions such as the loss of bone mass, the increase in bone fractures and vascular calcifications, as independent age-related disorders. However, during recent years, epidemiological reports have drawn attention to the striking association between bone and vascular disorders. The close physical relationship between endothelial cells and bone is significant, as it is this connection that permits the transfer of calcium from the bone to the arterial walls. This calcium redistribution, known as “the stealing phenomenon,” may account for the high incidence of cardiovascular disease and osteoporosis in individuals with spinal cord injury (SCI). Not only is it possible that an impaired vascular system may have negative consequences on bone health, but, the opposite has also been shown to occur, where diseased bone weakens vascular health. Similar to individuals with SCI, the extreme alterations in bone and cardiac physiology that occur in microgravity likely create a dangerous relationship which may have a detrimental impact on the health and safety of long duration crews. The SCI population therefore offers a unique model to assess the adaptations to inactivity, analogous to the disuse that occurs in microgravity. Purpose: The primary purpose of this presentation is to review the relationship between decreased bone mineral density and decreased cardiovascular function. Furthermore, the clinical significance of this association both in individuals with SCI, and in those exposed to microgravity will be discussed, along with potential therapeutic implications.
- Abstract document
- Manuscript document
(absent)