RT Journal Article SR Electronic T1 Induced pluripotent stem cells conditioned media (iPS-cm) modulates macrophage phenotype in the fibrotic lung JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P887 VO 44 IS Suppl 58 A1 Luca Tamò A1 Amiq Gazdhar A1 Anis Feki A1 Thomas Geiser YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P887.abstract AB Introduction: Macrophages are important cells involved in the pathogenesis and progression of pulmonary fibrosis (PF). Imbalance between classically activated (M1) and alternatively activated (M2) macrophages could play role in progression of PF. Factors which influence this balance need to be examined. We investigate the effect of conditioned media from human induced pluripotent stem cells (iPS-cm) on macrophages, in order to understand the previously shown antifibrotic mechanism of iPS.Methods: Human monocytes were polarized towards M1 and M2 phenotype, and migration properties were tested in vitro. Bleomycin injured rats where treated on d7 with iPSC-cm and FACS analysis was performed on d14 with isolated single cells from the digested lung.Results: iPS-cm increased migration of macrophages in vitro compared to medium control. Increased percentage of macrophages in bleomycin injured lung compared to normal control (26.2% ±1.4 vs 14.4% ±1.0). M1 and M2 populations were both increased in bleomycin injured lung (M1: 32.3% ±2.0 vs 5.7% ±0.3) (M2: 3.2% ±0.6 vs 1.1% ±0.2). Interestingly, iPS-cm treatment reduced percentage of macrophage to 17.4% ±1.2, moreover the original macrophage phenotype was partially restored (M1: 18.0% ±8.3; M2: 1.3 ±0.7).View this table: Conclusions: iPS-cm modulate macrophage phenotype in vivo and migratory properties in vitro. Targeting the macrophage phenotypical switch could be a possible therapy for PF.