A comparison of allogeneic and autologous mesenchymal stromal cells and osteoprogenitor cells in augmenting bone formation around massive bone tumor prostheses.

Spraying autologous mesenchymal stromal cells (MSCs) onto hydroxyapatite (HA)-coated ingrowth collars, located at the shoulder of massive bone tumor implants, significantly increased extracortical bone-bridging and osteointegration in an ovine model. In this study, we investigated the hypothesis that allogeneic MSCs and osteoprogenitor cells (OPCs) will augment bone growth equally when compared with autologous BMSCs. All collars were HA coated. In group i, the HA collar was coated with fibrin glue only. Cells were combined with fibrin glue and implants received (ii) 2 × 10(6) autologous MSCs, (iii) 10 × 10(6) autologous MSCs, (iv) 2 × 10(6) OPCs, (v) 10 × 10(6) OPCs, or (vi) 10 × 10(6) allogeneic MSCs. In group vii, collars were HA coated only. New bone area and bone-implant contact onto the ingrowth collar was quantified radiographically and using histological techniques. Results showed that no extracortical bone formed adjacent to any collars sprayed with allogeneic MSCs and significantly more new bone was measured when all other experimental groups were compared (p < 0.05 in all cases). Most bone growth and bone-implant contact occurred in the 10 × 10(6) OPC group. Spraying MSCs or OPCs onto the implant surface may be used in patients; however, further work is needed to determine the role of allogeneic cells in bone augmentation in vivo.