Bone diseases like osteoporosis and osteoarthritis are affecting an increasing number of people worldwide. The short- and long-term consequences are an increasing risk of fractures, total joint replacement and bone grafting. Current treatments of osteoporosis are based on inhibition of bone resorption and at best preserve bone volume but do not improve bone formation together with a high risk of complications like an osteonecrosis of the jaw. Furthermore, in clinical cases of bone loss or during osteoarticular prostheses surgeries, bone autograft remains the ‘gold standard’ for surgeon as bone substitutes or bone filler, respectively. In fact, despite the good clinical results of calcium phosphate materials in the same applications and their advantages over bone autograft, their lack of biological properties is still a major drawback. These examples clearly demonstrate the actual limits of the current clinical solutions in the field of treatment of bone disorders and bone tissue regeneration. A key factor for bone repair is the creation of the vascular network allowing optimal cell colonization and mineralized tissue formation. Recent studies have shown the crucial role of cells responsible of bone resorption (osteoclastic cells) in the initiation bone remodeling but also in the recruitment of blood vessel forming cell (endothelial cells). Taking together, this data can explain major issues caused by bisphosphonates as well as the limited application of synthetic materials for the treatment of bone defect. Thus a better knowledge of the communication between cells would highlight the mechanisms of the vascularisation process. This project aims to characterize the specific interactions between osteoclastic and endothelial cells in order to provide a new route both for the treatment of bone healing disorders and for the functionalization of synthetic bone substitutes. We believe that this strategy will accelerate vascularisation and improve bone tissue regeneration.