Influences of vascularization and osteogenic cells on heterotopic bone formation within a madreporic ceramic in rats

Research in biomaterials for bone reconstruction has led to elaborate osteogenic composites that combine porous ceramics with bone marrow stromal cells. The aim of this study was to evaluate the influence of direct vascularization of such composites on osteogenesis and the ability to produce a vascularized bone substitute transplant in an ectopic muscular site. Sixty-four coralline biomaterials were implanted in 32 Fisher rats under four conditions: (1) alone (reference group M, n = 16), (2) coated with bone marrow stromal cells (group MC, n = 16), (3) combined with a vascular pedicle (group MV, n = 16), or (4) coated with bone marrow stromal cells and combined with a vascular pedicle (MCV group, n = 16). The number of vessels in the pores (vessel-pore ratio) of the implants and the proportion of pores showing bone ingrowth (bone-pore ratio) were measured at 2, 4, 6, and 8 weeks on four implants of each group. Compared with the reference group, angiogenesis was higher when the biomaterial was combined with a vascular pedicle or was coated with osteoprogenitor cells. The association of both vascular pedicle and osteoprogenitor cells increased vascularization by 60 percent (p = 0.003) and osteogenesis by 62 percent (p < 0.001). A combination of both vascular pedicle and bone marrow osteoprogenitor cells in coralline implants enhances neovascularization and osteogenesis after implantation in ectopic intramuscular sites to a greater extent than either does alone.