Modeling and simulation of flow–osteocyte interaction in a lacuno-canalicular network

Abstract

Osteocytes are bone cells that can sense mechanical cues (stress and strain) and respond by releasing biochemical signals that direct bone remodeling. This process is called mechanotransduction which, in osteocytes, is not well understood yet because in vivo studies have proven difficult due to the complexity and inaccessibility of the flow–osteocyte lacuna-canaliculi system. While in silico studies (modeling and simulation) have become powerful, currently computational studies for the system often omit the fluid–structure interaction (FSI) between the cell and the surrounding fluids. To investigate the role of FSI in osteocyte mechanotransduction, we introduce a two-dimensional coarse-grained yet integrative model for flow–osteocyte interaction in a lacuno-canalicular network. The model uses the lattice Boltzmann immersed boundary framework to incorporate the flexible osteocyte (membrane, cytoskeleton, and cytosol), its processes, the interstitial fluid, and the rigid extracellular matrix that encases the system. One major result of our model is that the stress and strain tend to attain their local maxima near the regions where the processes meet the membrane of the main body.