Cells were trypsinized and resuspended in ECM gel with DMEM according to the manufacturer's instructions (Cell Biolabs, Inc) . Each well is duplicated for each experiment, and each experiment was repeated three times. For short term assays (after 4 hours of incubation at 37°C), 80 single HMEC cells were scored for the number of processes per cell. Cells were photographed at a magnification of x10 using Zeiss microscope, equipped with a video camera.