Figure 2 Angiogenesis: a multistep sequence. The process of angiogenesis is a sequence of events, some of which occur simultaneously. Proteolysis of the basement membrane is followed by directed locomotion of endothelial cells (chemotaxis). Endothelial cells begin to proliferate, forming initial tube‐like structures (sprouting). The final event in this sequence is maturation of microvessels, which is supported by adjacent cells, including pericytes. Background picture: human intestinal microvascular endothelial cells forming tubular structures in an extracellular matrix (own observations).