Immunocytochemical Characterization of ECFCs

For quality and purity control, each ECFC isolation was subjected to immunocytochemical characterization using antibodies against endothelial cell markers (CD31, von Willebrand factor (VWF)), fibroblast markers (CD90, TE-7) and muscle cell markers (smooth muscle actin (SMA), Desmin) as described previously.^{41 (link)} In brief, cells were seeded on glass chamber slides (ThermoFisher Scientific) and fixed with acetone (Merck). TBE pH 8.0 (Gatt-Koller, Absam, Austria) with 0.1% Tween (Sigma-Aldrich) was used as rehydration and washing buffer. Primary antibodies (Supplementary Table 2) were applied for 30 min and visualization was performed with the Ultra Vision horseradish peroxidase Polymer Kit (ThermoFisher Scientific). Images were generated using a light microscope (Olympus BX53) with the UC90 camera (Olympus) and the corresponding cellSens Standard software (Olympus).