Proliferation and osteogenic differentiation of cells from cortical bone cylinders, bone particles from mill, and drilling dust.
OBJECTIVE
The osteogenic potential of a graft is based on the parallel lines ability of cells to survive transplantation and to respond to local factors that stimulate new bone formation. Here we investigated the potential of cells that had grown out of porcine cortical bone grafts obtained by 3 preparation techniques to respond to mitogenic and osteogenic stimuli.


METHODS
Bone grafts were harvested from 2 pigs. Cortical bone was taken in cylindrical form and ground in a bone mill or harvested via drilling and aspiration.


RESULTS
Cell outgrowth was observed in all cortical bone cylinders, bone cylinders homogenized by mill, and 5 of 10 explants of bone dust collected upon drilling. After a 2-week culture period, the number of outgrown cells did not significantly differ among the 3 preparations. Bone cells showed increased proliferation in response to platelet-released supernatants as determined by 3 [H]-thymidine incorporation assay. When cultured under conditions that favor the expression of an osteogenic phenotype, the outgrown cells expressed alkaline phosphatase activity and transcripts of the osteoblast-specific marker osteocalcin. Individual cell preparations showed accumulation of mineral salts in their extracellular matrix. Bone cells also increased alkaline phosphatase activity in response to bone morphogenetic protein (BMP)-2, BMP-6, and BMP-7. The mitogenic and osteogenic response was obtained with cells from the mandible as well as from the maxilla, irrespective of the preparation technique.


CONCLUSIONS
These data show that cortical bone grafts contain cells that have the ability to proliferate and differentiate into the osteogenic lineage, suggesting that these cells can contribute to bone regeneration following transplantation.
Gruber
Reinhard
R
Medical University Vienna, Department of Oral Surgery, Vienna, Austria. reinhard.gruber@meduniwien.ac.at
Baron
Monika
M
Busenlechner
Dieter
D
Kandler
Barbara
B
Fuerst
Gabor
G
Watzek
Georg
G
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D001792:Blood Platelets; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D001861:Bone Regeneration / Q000502:physiology*; D016025:Bone Transplantation / Q000502:physiology*; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D008334:Mandible / Q000166:cytology; D008437:Maxilla / Q000166:cytology; D009930:Organic Chemicals; D015675:Osteocalcin / Q000096:biosynthesis; D010011:Osteocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013552:Swine
D019485:Bone Morphogenetic Proteins; D003470:Culture Media; D009930:Organic Chemicals; C420642:alpha minimal essential medium; D015675:Osteocalcin; D000469:Alkaline Phosphatase