[1] Justus Liebig Univ Giessen, Univ Giessen & Marburg Lung Ctr, German Ctr Lung Res DZL, Giessen, Germany
[2] Univ Southern Calif, Childrens Hosp Los Angeles, Dev Biol & Regenerat Program, Los Angeles, CA 90007 USA
[3] Univ Penn, Childrens Hosp Philadelphia, Dept Pediat, Philadelphia, PA 19104 USA