TIE2 expressing macrophages (TEMs) are important regulators of angiogenesis, i.e. the growth and remodeling of blood vessels. TEMs regulate initial blood vessel growth, but are also active during vascular remodeling and maturation. In this project we will investigate whether a balance between the TIE2 ligands, angiopoietin-1 and angiopoietin-2 drives TEMs to a pro-angiogenesis or a vessel maturation phenotype.