BoneKEy Reports | BoneKEy Watch
Wnt3a rescues bone grafting potential of tissue from aged animals
DOI:10.1038/bonekey.2013.194
Aging causes numerous changes in bone, including fatty degeneration in the bone marrow. These changes may be due to alterations in Wnt signaling, and Leucht et al. devised a series of bone graft experiments using a well-established model to find out more about the mechanisms involved.
After showing that mice show the same age-related fatty changes in bone marrow as humans, the authors compared bone grafts taken from aged and young mice. Those taken from the older animals generated significantly reduced new bone, confirming that the osteogenic capacity of their bone tissue was lower.
Bone marrow from aged and young animals was then tested for Wnt gene expression. Of the 19 Wnt genes studied, five were expressed at a significantly lower level in tissue from aged mice (Wnt3a, Wnt5a, Wnt5b, Wnt9a and Wnt10b).
The possibility of restoring the osteogenic potential of bone tissue from aged mice using Wnt3a was then investigated. Compared with control grafts, those treated with Wnt3a showed twice as much new bone formation within 7 days. Similar results were obtained in rabbits, and bone marrow-derived stem cells were identified as the cell type responding to Wnt3a.
Editor’s comment: This proof of concept study in mice and rabbits established that liposomal Wnt3a enhances cell survival and increases the osteogenic capacity of bone grafts from aged animals. This local treatment could conceivably be used to increase osteoinduction in bone grafting in patients.
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