In vivo transplantation of mammalian vascular organoids onto the chick chorioallantoic membrane reveals the formation of a hierarchical vascular network.

The dynamic remodeling of the nascent vascular network into a mature hierarchy is essential for embryo survival. Cell behaviors and signaling mechanisms are often investigated with animal models and perfused microchannels, giving insights into this process. To support these studies and enrich our understanding, we demonstrate a complementary approach using vascular organoids.