Published online Apr 26, 2015. doi: 10.4252/wjsc.v7.i3.630
Peer-review started: November 4, 2014
First decision: November 27, 2014
Revised: December 30, 2014
Accepted: January 18, 2015
Article in press: January 20, 2015
Published online: April 26, 2015
Processing time: 170 Days and 14.1 Hours
Bone is a highly vascularized tissue reliant on the close spatial and temporal association between blood vessels and bone cells. Therefore, cells that participate in vasculogenesis and osteogenesis play a pivotal role in bone formation during prenatal and postnatal periods. Nevertheless, spontaneous healing of bone fracture is occasionally impaired due to insufficient blood and cellular supply to the site of injury. In these cases, bone regeneration process is interrupted, which might result in delayed union or even nonunion of the fracture. Nonunion fracture is difficult to treat and have a high financial impact. In the last decade, numerous technological advancements in bone tissue engineering and cell-therapy opened new horizon in the field of bone regeneration. This review starts with presentation of the biological processes involved in bone development, bone remodeling, fracture healing process and the microenvironment at bone healing sites. Then, we discuss the rationale for using adult stem cells and listed the characteristics of the available cells for bone regeneration. The mechanism of action and epigenetic regulations for osteogenic differentiation are also described. Finally, we review the literature for translational and clinical trials that investigated the use of adult stem cells (mesenchymal stem cells, endothelial progenitor cells and CD34+ blood progenitors) for bone regeneration.
Core tip: Mesenchymal stem cells and blood derived progenitor cells have the potential to open new horizon for the treatment of bone defects. Numerous preclinical and clinical studies demonstrated angiogenic and osteogenic potential of these cells. Additional research is required in order to improve isolation and expansion techniques, as well as long term studies to follow the safety of this cellular approach.