Bioinorganic Angiogenesis

Causing a large diameter blood vessel to sprout branches and a capillary network on demand to create a new angiosome is key to harnessing to potential of regenerative medicine and advancing reconstructive surgery. Currently this can only be achieved by connecting a vein graft to an artery by microsurgery, the arteriovenous loop technique (AVL). The arterial blood pressure in the thin-walled vein is thought to drive remodelling to create branches, however the surgical complexity limits the application of the technique. In this study we demonstrate that unexpectedly, a vessel density of luminal branches in excess of that achieved by the surgical AVL approach can be induced simply by placing a vein in contact with a microporous calcium phosphate. Only osteoinductive biomaterials have been reported previously, this is thought to be the first report of an angio-inductive material. Pilot studies indicated that the material type greatly affected the degree of luminal vascularization. Material contact with the vein is not a requirement for luminal angiogenesis of the vein and together these findings point to a bioinorganic effect, wherein the degradation of the material both releases a stimulatory ionic milieu and creates space for the developing angiosome.