Article révisé par les pairs
Résumé : Bone remodelling is a complex physiological process including cellular and vascular factors, cytokines and growth factors. The osteocyte seems to play an activating key role in bone remodelling, according to the received signal. This process involves osteoblasts, osteoclasts and progenitor cells which are present in bone marrow as well as in other tissues. The deficiency in bone remodelling, present in several pathological situations, could be restored by cellular therapy. We develop two approaches : the first includes the use of autologous bone marrow samples concentrated in monocyte cells. The targeted cells are principally the mesenchymal stem cells (MSC) which can give rise to mature osteoblasts. This bone marrow concentrate is injected into the lesion by a percutaneous technique. This treatment has been efficiently applied in cases of aseptic osteonecrosis of the femoral head. The effect after 2 years is significant for pain, function, prevention of collapse and reduction of the necrotic zone. The second approach uses an intermediate stage. The bone marrow harvest is cultured to produce MSC proliferation and differentiation in preosteoblast cells. The percutaneously injected cells in the injured zone are thus already differentiated cells. We apply this treatment in cases of nonunion fractures. The preliminary results are promising.