Role of osteocytes in the adaptation of bone to mechanical loading

The mechanical performance of our skeleton is secured by the constant adaptation of bone to its mechanical loading environment. Mechanical adaptation of bone is brought about by the coordinated actions of osteoclasts and osteoblasts, which are orchestrated by the most mechano-sensitive cells in bone, the osteocytes. Loading on bone generates a flow of interstitial fluid through the lacuno-canalicular network in which the osteocytes are positioned. This flow is sensed by the osteocytes, which respond by the release of signaling factors such as nitric oxide, prostaglandins and Wnts, which alter the recruitment and activity of osteoblasts and osteoclasts, thereby affecting bone mass. Thus, any factor that alters the response of osteocytes to mechanical loading potentially affects bone mass. This paradigm could have implications for the field of rheumatology, where proinflammatory cytokines might affect bone mass by altering the response of osteocytes to mechanical loading.