Microvessel containing multi-cellular lumen formations of endothelial cells in a three-dimensional fibrin gel assay

Angiogenesis is the development of a new microvessel structure from the pre-existing one. It is a key mechanism during normal development as well as in cancer growth. In tissue engineering research, the ability of endothelial cells guidance for the growing microvessel containing multi-cellular lumen is a long-standing challenge now. This paper presents a three-dimensional (3D) cell culture system for the in vitro angiogenesis assay, in which imaging tools and assessment method of tube-like structure and multi-cellular lumen formation was validated. Phase contrast and fluorescence imaging using an inverted microscope were used to determine cell-cell and cell-matrix interactions. Laser scanning confocal microscope and traditional histological technique were used to confirm the development of tube-like structure and multicellular lumen formation. Further experiment using fluorescence fibrin gel confirmed the evidence of extracellular matrix degradation in the area of microvessel containing multicellular lumen