Mechanostat function during skeletal development.

these genes prevents development of skeletal muscle and mouse pups are born with a skeleton that lacks many of the features seen normally. Bones are straight instead of curved, and lack either the narrowing of the mid-shaft of the cortex or the flaring of the metaphyses seen in WT controls. Even more striking is the absence of the traction epiphyses, proving Julius Wolff’s assertion over 100 years ago that these develop because of muscular activity. MicroCT analysis of neonatal skeletons revealed reduced lengths of mineralized cortex, and low mineral density. These findings show that bone’s adaptive response to exercise begins in utero and that movement during skeletogenesis is a powerful influence on skeletal form at birth. If the fetal origins of adult disease hypothesis are applicable to bone, then the movements of the fetus may affect susceptibility to bone disease in later life some 50-60 years later. Hylonome