RT Journal Article SR Electronic T1 Bone marrow-derived mesenchymal stem cells transplantation in a model of bronchiolitis obliterans JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA4630 DO 10.1183/13993003.congress-2016.PA4630 VO 48 IS suppl 60 A1 Jose Luis Campo-Cañaveral de la Cruz A1 David Gómez de Antonio A1 Mercedes Zurita Castillo A1 Martin Santos González A1 Carmen González Lois A1 Andrés Varela de Ugarte YR 2016 UL http://erj.ersjournals.com/content/48/suppl_60/PA4630.abstract AB Introduction Bronchiolitis obliterans (BO) is the major cause of death in lung transplantation after 1 year. On the other hand, mesenchymal stem cells (MSC) have shown to participate in reparative processes.Objectives To reproduce a BO animal model and assess the effect of MSC for preventing the histologic lesion.Methods We developed an heterotopic tracheal transplantation rat model of BO. BO lesion was successfully reproduced at day 21 (control group). Then, we transplanted in 45 rats bone marrow-derived MSC through 3 routes (topical, endotracheal, endovascular) and at 3 time points (same day of tracheal grafting, at day 7 and 14) [5 individuals each group]. Variables: grade of tracheal lumen obliteration, fibrosis, neovascularization, histologic pattern. Flourescence In Situ Hibridation (FISH) and Inmunohistochemistry (IHQ) were used to detect MSC.Results All MSC groups had significant differences in histologic pattern with regard to control group (p 0.006), showing more neovessels and less fibrosis. The group who received MSC at day 7 presented less fibrosis (p 0.033), and the subgroup who received MSC at day 7 by endotracheal route showed less fibrosis and grade of lumen obliteration (p 0.048). FISH-IHQ showed MSC expressing type II neumocite markers and were localized into a neoformed alveolar-like tissue.Conclusions Reproducibility of a BO animal model is feasible. MSC transplanted in that model are able to modify the typical BO lesion, so a reparative effect might be attributed to MSC. Expression of a neumocite marker by MSC localized in neo alveolar-like tissue shows a certain degree of regenerative effect. Endotracheal route appears to be the best one to MSC transplantation.