TGFB1 and systemic sclerosis: Only one previously published experimental study showed that the activation of Vitamin D Receptor (VDR) by the synthetic VDR agonist paracalcitiol reduces the stimulatory effects of TGFβ on collagen production and on the formation of stress fibers in SSc fibroblasts, and prevents experimental fibrosis in two different mouse models of SSc 52.