Computational simulation of the mechanobiological regulation of bone remodeling by means of a coupled systems biology-micromechanical approach

Bone remodeling involves the coordinated removal of bone by osteoclasts and addition of bone by osteoblasts, a process that is modulated by the prevailing mechanical environment. Here we present a new computational model of bone remodeling, based on coupling a bone cell population model with micromechanical homogenization of bone stiffness. As for mechanoregulation, bone remodeling is controlled proportionally to the microscopic strain energy density, on the observation scale where the sensing of the mechanical loading actually takes place, estimated by means of continuum micromechanics-based strain concentration. This new approach allows us to address how biochemical changes influence bone remodeling and thus affect the composition and mechanical properties of bone, and what mechanisms are responsible for mechanoregulation of bone remodeling. Numerical studies highlight the capabilities of the model: we demonstrate that computationally simulated changes of the bone constituent volume fractions are in qualitative agreement with experimental observations for disuse syndromes.