Senescence of osteogenic cells. Review.

In older individuals the regeneration of bone tissue is delayed due to the diminished activity of osteoblasts, while osteogenic potency of human bone marrow stromal cells, also capable of forming bone, does not change with age. The number of osteoprogenitor cells is not reduced in ageing subjects, but their proliferating rate and the activity of their derivatives--osteoblasts, is markedly diminished, since the self-renewing potential of these cells is hindered. The senescence of osteoblasts in ageing people is also accelerated. Changes within the bone marrow microenvironment reduce osteogenic potential of osteoprogenitor cells leading to impaired bone formation seen in senility, while the potency for ectopic osteogenesis does not change with age. This review summarizes documented mechanisms of changes in osteogenic activity of cells in elderly.