Rolvien T, Milovanovic P, Schmidt FN, et al. - Given that gradual bone loss is associated immobilization as a result of long-term bed rest and that osteocytes represent the major mechanosensors in bone and translate mechanical into biochemical signals controlling bone remodeling, experts aspired to explore whether immobilization modifies the features of the osteocyte network in human cortical bone, via analyzing femoral diaphyseal bone specimens in immobilized female individuals. In addition, they contrasted these with age-matched postmenopausal individuals with primary osteoporosis. Control groups involved premenopausal and postmenopausal healthy people. They identified a declining rate of osteocyte density and canalicular density from premenopausal towards healthy postmenopausal and osteoporotic individuals with peculiar decreases in the immobilization group, while an inverse accumulation was observed in the number of hypermineralized lacunae. Findings thereby suggest that during immobilization, decreased osteocyte density and impaired connectivity are correlated with a specific bone loss pattern, showing a phenotype clearly distinct from postmenopausal osteoporosis. Periods of immobilization can lead to a loss of osteocyte survival signals, causing bone loss that is even higher than in osteoporosis states, while osteocytic osteolysis is still absent.