Tissue engineering: creation of long-lasting blood vessels.

The construction of stable blood vessels is a fundamental challenge for tissue engineering in regenerative medicine. Although certain genes can be introduced into vascular cells to enhance their survival and proliferation, these manipulations may be oncogenic. We show here that a network of long-lasting blood vessels can be formed in mice by co-implantation of vascular endothelial cells and mesenchymal precursor cells, by-passing the need for risky genetic manipulations. These networks are stable and functional for one year in vivo.