Figure 1: Electron microscopy pictures of MSC isolated from bone marrow, adult lung biopsies of lung-transplanted patients with good outcome and fetal lung tissue.

M = membrane of the insert, N = nucleus, arrowhead = MSC and * = mitochondria (a). Bone marrow derived MSC are longer (b) and wider (c) compared to lung derived MSC. Data are presented as mean (±SEM) and statistical analysis was performed by the Kruskal-Wallis test combined with Dunn’s multiple comparisons test, ***p < 0.001. Fetal lung derived MSC display a higher frequency of colonies compared to bone marrow MSC and adult lung MSC (d). Furthermore, fetal lung MSC have a higher proliferation rate compared to adult lung and bone marrow derived MSC (e). Data are shown as absorbance after 48 h (measured at 595 nm) subtracted by the 6 h absorbance. Data are presented as median and statistical analysis was performed by the Kruskal-Wallis test combined with Dunn’s multiple comparisons test, **p < 0.01, *p = < 0.05. The surface marker profiles are presented as percent positively stained cells. Data are presented as mean (±SEM) and statistical analysis was performed by 2way ANOVA combined with Tukey’s multiple comparisons test (f). The in vitro differentiation capacity (adipocyte, chondrocyte and osteoblast) of MSC isolated from bone marrow, adult lung and fetal lung tissue. Data are presented as number of cultures that were able to differentiate per total number of tested cultures (g).