Initial take, development, and function of transplanted engineered tissue substitutes are crucially dependent on rapid and adequate blood perfusion. Therefore, the development of rapidly and efficiently vascularized tissue grafts is vital for tissue engineering and regenerative medicine. Our goal is to develop pre-vascularized human skin grafts and to evaluate the effects of pre-vascularization on skin regeneration in vivo. We were able to generate a network of highly organotypic, branching, lumen-forming capillaries in engineered skin substitutes. After transplantation onto immuno-incompetent rats, histological analyses of the pre-vascularized skin substitutes showed that the engineered human vessels quickly connected to the vasculature of the recipient animal. This became obvious because the bio-engineered capillaries of human origin contained red blood cells of rat origin, and rapidly supplied the graft with oxygen and nutrients. (Montaño 2010 and Luginbühl 2012, manuscript in preparation).
