Figure 1: Tubular-like structures formation in Matrigel, after 48 hrs. (a) Phase contrast pictures: HC-ECs cultured alone form well organized tube-like structures; SSc- ECs cultured alone failed to form well organized tube-like structures; HC-ECs/HC-MSCs co-culture: the picture shows an increased ability to form a well-organized tube-like network; SSc-ECs/HC-MSCs co-culture: a decreased capacity of HC-MSCs to improve the tubular formation by SSc-ECs, when cultured alone, can be observed; HC-ECs/SSc-MSCs co-culture: the presence of SSc-MSCs did not influence the ability of HC-ECs to form normal tubular structures. SSc-ECs/SSc-MSCs co-culture: the impairment to form tubular structures of SSc-ECs was not improved by SSc-MSCs. The fluorescent images showed ECs (green) and MSCs (red) distribution. Pictures are representative of all experiments. Original magnification 20X. (c) The total tube length of each well was measured as branching index= (master junction/area)×1000 and photographed. Results are expressed as Median (range) of triplicate experiments (**=p=0.0002; ***=p<0.0001).