Do autologous mesenchymal stem cells augment bone growth and contact to massive bone tumor implants?

This study investigated the hypothesis that spraying autologous mesenchymal stem cells (MSCs) onto grooved hydroxyapatite (HA) coated collars of segmental bone tumor implants would increase bone growth and contact to the implant surface in an ovine model. Autologous MSCs were isolated from bone marrow, grown in culture and during surgery implants in group 1 were sprayed with MSCs, suspended within fibrin glue. Implants in group 2 received no MSC therapy and acted as control. Implants remained in vivo for 6 months. New bone area and contact to the implant was quantified on radiographs and histologically. Radiographic analysis demonstrated greater total bone area in the MSC treated group in both ML (MSC = 79.738 mm2 +/- 22.964; control = 30.135 mm2 +/- 6.717) (p = 0.018) and AP (MSC = 90.338 +/- 19.361 mm2; control = 57.384 +/- 9.035 mm2 (p = 0.074) radiographs at 6 months. Results demonstrated significantly increased bone growth in the MSC group at 2 (p = 0.03) and 3 months (p < 0.05). Histological analysis demonstrated significantly greater bone area adjacent to the collars in the treated group (53.994 +/- 10.641 mm2) when compared with the control group 21.069 +/- 7.339 mm2 (p = 0.020). Increased bone contact in the MSC group (19.833 +/- 8.729 %) was observed when compared with controls (8.667 +/- 8.667%). This novel application of spraying MSCs onto the implant surface has significant implications for the future of successful implant fixation.