Pro-angiogenic activity of hydrogel-released HATMSC2 supernatant. (a) Representative images of in vitro angiogenesis of skin endothelial cells (HSkMEC.2) following 22h culture in the presence of supernatant-loaded hydrogel or supernatant treatment alone. The supernatant alone group (Sup) and Matrigel control (Control) are our positive controls. Graphs present quantification of angiogenesis by the number of nodes, total length of the tubes and mesh size. Inserts on the left top corners are 2.5 x magnifications of the original images. Data represent as mean ± SD, n = 2; (b) Relative expression of proangiogenic miRNAs, miR-210, miR-126, miR-296, and miR-378 in HATMSC2 supernatant. The expression of miRs was determined in a real-time RT-PCR experiment and measured relative to the control (HATMSC2 cells). Data were presented as mean ± SD values, n = 2.