Clinical considerations of regenerative medicine in osteoporosis.

Osteoporosis-related fractures may severely limit activities of daily living and may require bed rest, which may become life threatening in elderly people. Osteoporosis has attracted much attention recently because of its severe effects on the daily activities of older people and because it is now treatable, thanks to recent advances in drug discovery. However, these medications have yet to reduce fully the number of fracture cases. On the other hand, declines in the number and function of osteoblasts and mesenchymal stem cells (MSCs) in the bone marrow and within the periosteum lead to reduced osteogenesis and bone formation. Thus, bone regeneration, through induction of MSCs, provides a rational therapeutic strategy for preventing or treating age-related osteoporosis. In this review, I summarize cell-related issues in osteoporosis, stem cell candidates for cell-based therapy, and possible therapeutic strategies for osteoporosis.