In vitro vasculogenic property of monocytic EPCs in Matrigel® culture. Monocytic EPCs labeled with PKH67 (green) and HUVECs labeled with Dil-acetylated LDL (red) were cultured together on Matrigel®. (a) Typical phase-contrast (left) and fluorescent (right) images of the same field of monocytic EPCs from an SSc patient (upper) and a healthy control (lower). An arrow indicates a monocytic EPC-derived cell incorporated into the tubular structure. Scale bars = 100 μm. (b) The vasculogenic property of monocytic EPCs was calculated as the number of monocytic EPCs within the tubular structure divided by the total tube length (cells/mm), and compared between SSc patients and healthy controls. Horizontal bars indicate the mean values.