Vascularization and Angiogenesis in Tissue Engineering: Beyond Creating Static Networks

Engineered tissues need a vascular network to supply cells with nutrients and oxygen after implantation. A network that can connect to the vasculature of the patient after implantation can be included during in vitro culture. For optimal integration, this network needs to be highly organized, including venules, capillaries, and arterioles, to supply all of the cells with sufficient nutrients. Owing to the importance of vascularization for the clinical applicability of tissue engineering, many approaches have been investigated to include an organized vascular network in tissue constructs. This review will give an overview of recent efforts, and will propose future perspectives to engineer the optimal, functional vascular network.

TrendsEngineered tissues of a clinically relevant size need a vascular network to supply the cells with nutrients and oxygen. Including a vascular network before implantation can aid in this need, by connecting to the vasculature of the patient.To supply all cells with sufficient nutrients, and to successfully connect to the patient vasculature, the engineered vascular network needs to be highly organized. Using microfabrication technology such as photo patterning and bioprinting, the initial organization of vascular networks can be designed and controlled.The geometry of vascular networks can also be controlled by adapting local microenvironments. The patterning of mechanical signals, fluid flows, or the availability of growth factors leads to directed vascular organization.