EDN1 and systemic sclerosis: In agreement with previous studies [24–27], these findings strongly suggest that endothelial cells can impact the function of fibroblasts inducing a pro-fibrotic phenotype and that such effect on fibroblasts might be mediated by both IL-6 and TGF-β synthetized by endothelial cells in response to SSc-IC stimulation, as documented by the high inhibition rates in et-1 mRNA levels.