Allografts supercharged with bone-marrow-derived mesenchymal stem cells possess equivalent osteogenic capacity to that of autograft: a study with long-term follow-ups of human biopsies.

PURPOSE: Bone-marrow-derived mesenchymal stem cells (BM-MSCs) have been proposed to enhance bone formation in allografts. However, it is not known whether a combination of MSCs, contained in bone marrow concentrate (BMC) and structural allograft could be better than an allograft without MSCs and equivalent to a femoral head autograft in terms of histologic bone formation and long-term cellularity in the graft. After ten years of follow-up, three types of grafts: those initially loaded with BM-MSCs; dead, irradiated allografts; autografts.
MATERIALS AND METHODS: Twenty patients received acetabular grafting during hip surgery and subsequently underwent femoral hip revision eight to 13 years later (average 10 years). Revision surgery was for reasons other than graft failure. These 20 patients had received eight allografts initially loaded with BM-MSCs: six dead irradiated allografts and six autografts. The number of MSCs present in the three types of graft were evaluated at the time of initial surgery and at revision. New bone formation associated in the acetabular graft was assessed by histology and calculated as a percentage of total available bony area.
RESULTS: At the most recent follow-ups (average 10 years), concentration of MSCs in allografts previously loaded with BM-MSCs was higher than that found in autografts. There were low or no MSCs found in uncharged allografts. New-bone-formation analysis showed that allografts loaded with BM-MSCs produced more new bone (35 %; range 20-50 %) compared with either uncharged allografts (9 %; range 2-15 %) or autografts (24 %; range 12-32 %).
CONCLUSIONS: Our observations with allografts charged with BM-MSCs provides evidence in support of a long-term benefit of supercharging bone allografts with autologous BM-MSCs.