VIVOIMAG · Multimodal imaging of the in vivo fate of bone transplants

Multimodal imaging of the in vivo fate of bone transplants

Millions of bone grafts are being performed worldwide to repair large segments of bone lost due to trauma, surgery and other causes. It is estimated that the bone graft market exceeds $2.5 billion/year. A continuously ageing population forecasts a steady increase in those numbers. Autologous bone transplants (those in which the recipient and donor are the same patient) have large osteogenic potential and present no biocompatibility problems, but they have several problems and risks that can be avoided using engineered tissue. Bone harvests, mostly taken from the iliac crest, rib, fibula, or tibia of the patients’ bone, do not always provide sufficient quantities, and can be associated with potential complications of pain, blood loss, infection, and radiation injury. On the other hand, engineered tissue does not have these drawbacks. In addition, it is also cost effective, since it can be produced and delivered to the patient at a point of care environment. However, there are important challenges to address since the technology strongly relies on the correct cell differentiation within the scaffold, therapeutic solutions that use adult bone marrow derived cells lack the complexity and structure associated with the bone tissue required for repair and lack of vascularisation in the engineered tissue result in necrosis after implantation. Thus the need for novel and efficient methods to produce efficient bone grafts, as well as assess the success of bone treatments has high social importance. The main objective of VIVOIMAG is to develop bone implants including a new contrast agent sensitive to enzymatic activity of metaloproteases, which will permit for the first time to follow the integration and cell differentiation activity in bone tissue bioreactors in vitro and in grafts in vivo using non invasive imaging techniques. The final goal of the project is to provide this collagen based contrast agent and use standard MRI as a tool to assess the efficiency of new bone treatments. In this way a clinically available, non invasive and affordable technology will be exploited for tissue engineering. After the completion of the action, these goals were indeed met. Bone implants were designed and constructed providing the ability to promote enzymatic activity of metaloproteases and the capability to be labeled with different contrast agents. Thus, they can be monitored through multi-modal imaging techniques. In addition, a complete multi-modal imaging platform, that enables the complementary efficiency evaluation of new bone graphs, has been established.

Data: CORDIS, © European Union