Fig. 1

Systemic sclerosis (SSc) platelet releasate inhibits angiogenesis. a Representative images of Matrigel cultures of dermal human microvascular endothelial cells (DMVECs) after 6 h in culture. Healthy control and SSc platelet supernatants were cultured at 10 % vol/vol. Left and right columns represent different magnifications (magnification is 10x for the first column and 20x for the second column). b Capillary morphogenesis was quantified by measuring the length of capillary projections (*p < 0.01, t test). Data are mean ± standard deviation of six duplicate experiments. c Endothelin-1 mRNA expression in DMVECs after 24 h of culture in platelet-conditioned medium. Endothelin-1 was upregulated after the cells were cultured with SSc platelet supernatants (p < 0.05, Mann–Whitney U test). NS non-stimulated, VEGF vascular endothelial growth factor