There's another interesting article on Biosingularity about the application of mesenchymal stem cells to bone regeneration, which also shows promise for tissue engineering in general.

Biosingularity � Blog Archive � Findings advance use of adult stem cells for replacement bone

In a significant advance for regenerative medicine, researchers at Rice University have discovered a new way to culture adult stem cells from bone marrow such that the cells themselves produce a growth matrix that is rich in important biochemical growth factors.