Final Report Summary - REMOTE (Real-time monitoring of load induced remodeling in tissue-engineered bone) The REMOTE project has focused on engineering a 3D in vitro bone tissue model displaying one of the bone’s most important inherent functional properties: to adapt its micro-structure to meet mechanical demands imposed by loads. It aims at incorporating both signaling between bone-forming osteoblasts and bone-resorbing osteoclasts and the assessment of the influence of spatio-temporal changes. We have investigated both into the development of a platform for controlled interventions (chemical and mechanical) for the formation of mineralized extracellular matrix (ECM) and have followed tissue development over time with quantitative longitudinal micro-computed tomography monitoring. Within the REMOTE project, we have identified various parameters that positively/negatively affect human cell behavior. The thorough characterization of these parameters enables future researchers to make (better) informed choices on their cell culturing ingredients/environments. We propose seeding bone tissue engineering scaffolds dynamically with the use of an orbital shaker because it affects not only cell attachment and distribution, but also tissue differentiation in 3D. We have further managed to provide an environment that enables osteoblasts to embed themselves in their own matrix and to further differentiate into osteocytes - which has so far not been achieved. Such model comprising the three bone-typical cell types can further advance the current 3D in vitro bone tissue engineering systems to resemble natural bone more closely. In terms of bone resorption, we have developed a protocol that promotes both morphological as well as functional differentiation of osteoclasts from human blood-derived cells in 2D. Although still preliminary, we have developed a system to longitudinally monitor in vitro tissue formation and resorption in 3D in parallel with micro-computed tomography in a co-culture system. Computationally, a multiscale framework that can the micro-fluidic (mechanical) environment within the scaffolds at low computational costs. The developed in silico models allow to simulate bone tissue growth under mechanical stimulation and will further allow to optimize mechanical loading conditions within the bioreactor and to design ideal scaffold geometries.The REMOTE project has reached its aim to engineer thoroughly characterized 3D in vitro bone model that changes micro-structure in response to chemical input or mechanical loads. We provide both a longitudinal monitoring approach and a computational framework that supports this system. We have gone beyond of what we have proposed by showing that it is possible to further differentiate human osteoblasts into osteocytes in vitro. This is an important step as it advances our model even further to mimic a humanized 3D in vitro bone tissue model that resemble natural bone more closely. In conclusion, these results will have a societal impact in the future by applying the knowledge generated in REMOTE to address bone diseases such as osteoporosis where the bone remodeling process is out of balance.
