無重力における骨代謝と骨粗鬆症

Mechanical unloading causes rapid and severe bone loss in astronauts subjected to microgravity or bed-ridden patients, which is designated as immobilization osteoporosis. Metabolic changes in unloaded bone are characterized by “uncoupling” which involves both enhanced bone resorption and impaired bone formation. Although it has long been well recognized and extensively studied, the pathophysiology of immobilization osteoporosis is not yet fully understood. This overview will focus on our recent understanding of the pathophysiology of immobilization osteoporosis and the mechanism by which mechanical loading affects bone metabolism. Finally, the current therapeutic approaches including anti-resorptive bisphosphonates as well as future aspects in the treatment of immobilization osteoporosis will be discussed.