The use of extracorporeal shock wave-stimulated periosteal cells for orthotopic bone generation

The cambium cells of the periosteum, which are known osteoprogenitor cells, have limited suitability for clinical applications of tissue engineering in their native state due to their low cell number (2-5 cells thick). Extracorporeal shock waves (ESWs) have been shown to cause rapid periosteal cambium cell proliferation and subsequent periosteal osteogenesis. This work investigates a novel strategy for orthotopic bone generation: applying ESW therapy as a noninvasive, inexpensive, and rapid method for stimulating cambium cell proliferation, and combining these cells with a bioactive scaffold for bone growth. ESWs applied to the rabbit medial tibia resulted in a significant 2.7-fold increase in cambium cell number and a 4-fold increase in cambium cell thickness at 4 days post-ESW. ESW-stimulated, or nontreated control, periosteal cells were elevated in situ and overlaid on an anorganic bovine bone scaffold to interrogate their ability to form bone. At 2 weeks post-surgery, there was a significant increase in all key outcome variables for the ESW-stimulated group when compared with controls: a 4-fold increase in osseous tissue in the upper half of the scaffold underlying the periosteum; a 12-fold increase in osseous tissue overlying the scaffold; and a 2-fold increase in callus size. These results successfully demonstrated the efficacy of ESW-stimulated periosteum for orthotopic bone generation.