Autologous bone marrow stromal cells loaded onto porous hydroxyapatite ceramic accelerate bone repair in critical-size defects of sheep long bones

摘要

The ability of marrow-derived osteoprogenitor cells to promote repair ofcritical-size tibial gaps upon autologoustransplantation on a hydroxyapatite ceramic (HAC)carrier was tested in a sheep model. Conditions forin vitro expansion of sheep bone marrow stromal cells(BMSC) were established and the osteogenic potentialof the expanded cells was validated. Ectopicimplantation of sheep BMSC in immunocompromised miceled to extensive bone formation. When used to repairtibial gaps in sheep, cell-loaded implants (n 2)conducted a far more extensive bone formation than didcell-free HAC cylinders (n=2) over a 2-month period.In cell-loaded implants, bone formation was found tooccur both within the internal macropore space andaround the HAC cylinder while in control cell-freeimplants, bone formation was limited mostly to theouter surface and was not observed in most of the innerpores. As tested in an indentation assay, thestiffness of the complex HAC-bone material was foundto be higher in cell-loaded implants compared tocontrols. Our pilot study on a limited number oflarge-sized animals suggests that the use ofautologous BMSC in conjunction with HAC-basedcarriers results in faster bone repair compared to HACalone. Potentially this combination could be usedclinically in the treatment of extensive long bone defects.