Future studies might want to put a focus on other factors, like CXC-motive-chemokinereceptor 4 (CXCR-4), insulin-like growth factor 1 (IGF-1), stromal-derived factor 1 (SDF-1) and T-cell derived interferone-y (IFN-v)–which have been shown to mobilize MSC from the bone marrow [22,47] and might thus be involved in an ECMO-induced increase in MSC numbers in ARDS. This evidence concerns the gene CXCR4 and acute respiratory distress syndrome.