The response to profibrotic stimuli was however similar in lung fibroblasts from control and COPD subjects., indicating that the response to TGF-β is not impaired in COPD, though the profibrotic stimuli had the potential to induce or exasperate differences both between healthy and COPD (as seen in IL-6, IL-8, and PGE2), and between normoxia and hypoxia (as seen in PGF1α). Here, TGFB1 is linked to chronic obstructive pulmonary disease.