Bone regeneration: current concepts and future directions

Abstract

Bone regeneration is a complex, well-orchestrated physiological process of bone formation, which can be seen during normal fracture healing, and is involved in continuous remodelling throughout adult life. However, there are complex clinical conditions in which bone regeneration is required in large quantity, such as for skeletal reconstruction of large bone defects created by trauma, infection, tumour resection and skeletal abnormalities, or cases in which the regenerative process is compromised, including avascular necrosis, atrophic non-unions and osteoporosis. Currently, there is a plethora of different strategies to augment the impaired or 'insufficient' bone-regeneration process, including the 'gold standard' autologous bone graft, free fibula vascularised graft, allograft implantation, and use of growth factors, osteoconductive scaffolds, osteoprogenitor cells and distraction osteogenesis. Improved 'local' strategies in terms of tissue engineering and gene therapy, or even 'systemic' enhancement of bone repair, are under intense investigation, in an effort to overcome the limitations of the current methods, to produce bone-graft substitutes with biomechanical properties that are as identical to normal bone as possible, to accelerate the overall regeneration process, or even to address systemic conditions, such as skeletal disorders and osteoporosis.

In vitro degradation of calcium phosphates: Effect of multiscale porosity, textural properties and composition

“…Among synthetic bone grafts [5][6][7], calcium phosphates (CaP) are very interesting for remodelling purposes as they possess a close resemblance to the mineral phase of natural bone consisting of~70 wt% of nanocrystalline hydroxyapatite (HA) [8]. Owing to the close compositional resemblance of CaP to bone mineral, they can induce a biological response similar to that taking place during bone remodelling.…”

The influence of hydrostatic pressure on tissue engineered bone development

“…By using autologous cells (donor and recipient being the same person), often seeded onto or into a scaffold which acts as a template for the developing tissue, tissue engineered products have many advantages for the replacement or treatment of damaged or diseased bone over traditional approaches, such as either bone grafting or non-living prostheses. The quantity of autologous bone that can be harvested for a bone graft is limited and the surgical procedures involved have a high risk of complications, while there can be problems with rejection and infection during allogeneic (donor and recipient being different people) bone grafting (Dimitriou et al, 2011;Schroeder and Mosheiff, 2011). Non-living prostheses, for example metallic or ceramic implants, are not able to easily biologically integrate into the surrounding tissue.…”

Growth plate expression profiling: Large and small breed dogs provide new insights in endochondral bone formation

“…Even more so, it is considered a model to develop new regenerative strategies3, 4 addressing large bone defects 5. As intramembranous bone formation is often not successful in the regeneration of these defects due to inadequate blood supply, these defects might profit from secondary bone formation, as chondrocytes can withstand the low oxygen tension 4.…”