Editors' ChoiceTissue Engineering

Sticks and Stones and Mending Bones

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Science Translational Medicine  30 Jun 2010:
Vol. 2, Issue 38, pp. 38ec105
DOI: 10.1126/scitranslmed.3001405

Sticks and stones may break one’s bones, but those broken bones usually heal to be good as new with a little help from a doctor. However, if the damage is extensive or if the blood circulation around the bone is poor because of another medical condition, then those broken bones may need more extensive help to heal fully. For these situations, tissue engineers have been developing engineered bone grafts that contain blood vessel precursor cells or that have been treated with drugs to stimulate blood vessel formation. However, grafts created using either of these approaches have only short-term benefits. To create a better vascularized bone graft, Unger et al. took a new approach by growing tiny blood vessels—microcapillaries—in the bone graft before implantation.

To induce microcapillaries to form, Unger et al. seeded human microcapillary endothelial cells and human osteoblasts—cells responsible for bone formation—onto silk scaffolds and then cultured these scaffolds in a laboratory. After 7 days in culture, microcapillaries began to form within the scaffold. To test whether they were functional in vivo, cell-seeded scaffolds were implanted into skin pouches of mice after 14 days of laboratory culture. After an additional 14 days in the mice, the scaffolds were retrieved. The researchers found that the seeded human cells remained viable and that the microcapillaries contained mouse red blood cells, which is evidence that these vessels connected to the host animal’s circulatory system. With continued research, these prevascularized bone grafts may one day help doctors mend bones no matter how bad the sticks and stones or medical conditions.

R. E. Unger et al., The rapid anastomosis between prevascularized networks on silk fibroin scaffolds generated in vitro with cocultures of human microvascular endothelial and osteoblast cells and the host vasculature. Biomaterials 17 June 2010 (10.1016/j.biomaterials.2010.05.057). [Abstract]

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