In accordance with previous reports [20, 28], the number of apoptotic cells (Annexin V positive and propidium iodide negative) was increased in IPF and donor cells treated with heparin + FGF1 compared to starved, non-treated controls: 20 % vs. 40 % in donor fibroblasts (Fig. 6a,b) and 18 % vs. 50 % in IPF fibroblasts (Fig. 6a,b’). Here, FGF1 is linked to idiopathic pulmonary fibrosis.