TGFB1 and chronic obstructive pulmonary disease: Importantly, following 48 h of treatment with TGFβ1 or GHK on lung fibroblasts from former smokers with COPD, we were able to restore this intrinsic defect, which we propose is through organization of the actin cytoskeleton to a contractile phenotype as demonstrated by the confocal images displayed in Figure 6a.