Morphogenetic Mechanisms of Endothelial Cells During Lumen Formation in Sprouting Angiogenesis

Different mechanisms such as cell migration, proliferation, branching, anastomosis, and lumen formation occur during the angiogenesis process. Lumen formation is one of the critical mechanisms which is not only necessary for the functional plexus but also for continuing of angiogenesis process. Although multiple studies investigated this mechanism during the angiogenesis process in both in vivo and in vitro conditions, it is not fully understood yet. Different studies have suggested distinctive mechanisms as the main mechanism for lumen formation. Recent studies, however, have shown the fundamental role of blood flow hemodynamics, especially during in vivo lumen formation. This newly introduced mechanism is called ''inverse membrane blebbing''; suggesting that blood pressure causes the formation and expansion of lumen during the in vivo angiogenesis process. This paper reviews cell behavior during lumen formation in the angiogenesis process on a cellular scale.