Generation of osteoinductive grafts by three-dimensional perfusion culture of human bone marrow cells into porous ceramic scaffolds

In this work, we investigated whether osteo-inductive constructs can be generated by isolationand expansion of sheep bone marrow stromal cells(BMSC) directly within three-dimensional (3D) ceramicscaffolds, bypassing the typical phase of monolayer (2D)expansion prior to scaffold loading. Nucleated cells fromsheep bonemarrowaspiratewere seeded into 3D ceramicscaffolds either by static loading or under perfusion flowand maintained in culture for up to 14 days. The resultingconstructswereexposed toenzymatic treatment toassessthe number and lineage of extracted cells, or implantedsubcutaneously in nude mice to test their capacity toinduce bone formation. As a control, BMSC expanded inmonolayer for 14 dayswere also seeded into the scaffoldsand implanted. BMSC could be isolated and expandeddirectly in the 3D ceramic scaffolds, although theyproliferated slower than in2D.Uponectopic implantation,the resulting constructs formed a higher amount of bonetissue than constructs loaded with the same number of2D-expanded cells. Constructs cultivated for 14 daysgenerated significantly more bone tissue than thosecultured for 3 days. No differences in bone formationwere found between samples seeded by static loading orunder perfusion. In conclusion, the culture of bonemarrow nucleated cells directly on 3D ceramic scaffoldsrepresents a promising approach to expand BMSC andstreamline the engineering of osteoinductive grafts.2005 Wiley Periodicals, Inc.