Mechanobiology of Bone Tissue and Bone Cells

Excerpt

Bone remodeling is the continuous turnover of bone matrix and mineral by bone resorption (activity of osteoclasts) and formation (activity of osteoblasts) in the adult skeleton. The mechanical environment plays an essential role in the regulation of bone remodeling in intact bone and of modeling during bone repair. Reduced loading during long-term immobilization or microgravity can result in significant bone loss. In contrast mechanical loading enhances bone formation and directs the newly formed bone along the local loading direction. In bone repair, too, the mechanical environment regulates osteogenesis. Bone cells respond directly or indirectly to the local strains engendered in their neighbourhood by external loading activity. The process of translating the physical stimulus into the biological response, called mechanotransduction, is up to now poorly understood. Several in vitro studies with various mechanical stimuli revealed various effects in bone cells due to loading and the involvement of numerous signal transduction pathways in mechanotransduction. Here we discuss mechanical factors regulating bone repair and focus on recent data concerning signal transduction pathways, effects of mechanical strain in osteoblasts, and on mechanical aspects in bone tissue engineering.