Vascularization remains one of the primary obstacles in the repair of bone defects. In the previous issue of Stem Cell Research &Therapy, Pedersen and colleagues show that co-immobilization of endothelial cells and mesenchymal stem cells in a tissue-engineered construct can achieve functional microvascular networks in vivo. These very interesting findings, together with other state-of-the-art research in this field, are presented in this commentary. They highlight the vital role of mesenchymal stem cells as supporting cells to nascent blood vessels. The development of pre-vascularized implants by using clinically relevant cell sources, which could lead to rapid integration into the host tissue, would be of immense interest.