TGFB1 and idiopathic pulmonary fibrosis: Moreover, we found that there was little difference in response to TGF-β in the lung fibroblasts isolated from IPF patients compared to those from control donors cultured in standard conditions, as reported by other authors [28], since in both the control and IPF fibroblasts, there was an increase in collagens, elastin, and fibronectin expression after the TGF-β challenge, followed by a significant decrease after Hylach treatments, which was higher than that exerted by the native HA.