In vivo transplantation of autogenous marrow-derived cells following rapid intraoperative magnetic separation based on hyaluronan to augment bone regeneration.
BACKGROUND
This project was designed to test the hypothesis that rapid intraoperative processing of bone marrow based on hyaluronan (HA) could be used to improve the outcome of local bone regeneration if the concentration and prevalence of marrow-derived connective tissue progenitors (CTPs) could be increased and nonprogenitors depleted before implantation.


METHODS
HA was used as a marker for positive selection of marrow-derived CTPs using magnetic separation (MS) to obtain a population of HA-positive cells with an increased CTP prevalence. Mineralized cancellous allograft (MCA) was used as an osteoconductive carrier scaffold for loading of HA-positive cells. The canine femoral multidefect model was used and four cylindrical defects measuring 10 mm in diameter and 15 mm in length were grafted with MCA combined with unprocessed marrow or with MS processed marrow that was enriched in HA(+) CTPs and depleted in red blood cells and nonprogenitors. Outcome was assessed at 4 weeks using quantitative 3D microcomputed tomography (micro-CT) analysis of bone formation and histomorphological assessment.


RESULTS
Histomorphological assessment showed a significant increase in new bone formation and in the vascular sinus area in the MS-processed defects. Robust bone formation was found throughout the defect area in both groups (defects grafted with unprocessed marrow or with MS processed marrow.) Percent bone volume in the defects, as assessed by micro-CT, was greater in defects engrafted with MS processed cells, but the difference was not statistically significant.


CONCLUSIONS
Rapid intraoperative MS processing to enrich CTPs based on HA as a surface marker can be used to increase the concentration and prevalence of CTPs. MCA grafts supplemented with heparinized bone marrow or MS processed cells resulted in a robust and advanced stage of bone regeneration at 4 weeks. A greater new bone formation and vascular sinus area was found in defects grafted with MS processed cells. These data suggest that MS processing may be used to enhance the performance of marrow-derived CTPs in clinical bone regeneration procedures. Further assessment in a more stringent bone defect model is proposed.
Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
Tonya
T
Caralla
Powrnima
P
Joshi
Sean
S
Fleury
Viviane
V
Luangphakdy
Kentaro
K
Shinohara
Hui
H
Pan
Cynthia
C
Boehm
Amit
A
Vasanji
Theresa E
TE
Hefferan
Esteban
E
Walker
Michael
M
Yaszemski
Vincent
V
Hascall
Maciej
M
Zborowski
George F
GF
Muschler
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D016026:Bone Marrow Transplantation / Q000379:methods*; D001861:Bone Regeneration / Q000502:physiology*; D002469:Cell Separation / Q000379:methods*; D002478:Cells, Cultured; D004285:Dogs; D005264:Femoral Fractures / Q000473:pathology / Q000601:surgery*; D006820:Hyaluronic Acid / Q000378:metabolism*; D018189:Immunomagnetic Separation / Q000379:methods*; D016896:Treatment Outcome
D006820:Hyaluronic Acid