Mei and colleagues enhanced the effi cacy of mesen chymal stem/stromal cells in endotoxin-induced ALI by transducing them to overexpress angiopoeitin-1 (Figure 4 ) [39] . Mesenchymal stem/stromal cells overexpressing IL-10 decreased alveolar infi ltration of CD4 and CD8 T cells following lung ischemia-reperfusion injury [65] . Bone marrow stem cells expressing keratinocyte growth factor attenuate bleomycin-induced lung injury [66] . Non stem cells can also be used to deliver genes to the injured lung [67] . Fibroblasts overexpressing angiopoeitin-1 attenuate endotoxin-induced lung injury [40] , while fi broblasts overexpressing vascular endothelial growth factor and endothelial nitric oxide synthase can attenuate or even reverse endotoxin-induced ALI [68] .