TY - JOUR T1 - Structural differences in airways during chronic rejection after lung transplantation: A (micro)-CT analysis JF - European Respiratory Journal JO - Eur Respir J VL - 40 IS - Suppl 56 SP - 1855 AU - Stijn Verleden AU - Stijn Willems AU - David Ruttens AU - Robin Vos AU - John McDonough AU - Annemie Vaneylen AU - Erik Verbeken AU - Johny Verschakelen AU - Dirk Van Raemdonck AU - Benoït Rondelet AU - Christiane Knoop AU - Marc Decramer AU - James Hogg AU - Geert Verleden AU - Bart Vanaudenaerde Y1 - 2012/09/01 UR - http://erj.ersjournals.com/content/40/Suppl_56/1855.abstract N2 - Chronic rejection is a major problem after lung transplantation (Tx) and is accepted to be a small airway disease. Recently a distinction between an obstructive (fBOS) and restrictive phenotype (RAS) has been made. We aimed to investigate structural differences.Human explant lungs from 5 fBOS and 3 RAS patients were collected during reTx, were air-inflated to TLC, frozen solid in liquid nitrogen vapor and frozen specimens were examined by HRCT. Unused donor lung (n=1) served as control. The lungs were kept frozen while cut in 2cm slices and cylinders of 1.4cm diameter were removed. These were fixed at -20°C in a solution of acetone/1% gluteraldehyde and warmed to 25°C, dried and scanned with microCT (skyscan1172, Belgium).HRCT images showed that RAS lungs displayed a lower number of airways starting at generation 5. In patients with fBOS >50% of the airways get obstructed at generation 6 (figure 1), mainly in airways <2mm (82%). MicroCT analysis shows a lower number of terminal bronchioles in RAS patients (2/ml of tissue vs 4.5/ml in fBOS and 5/ml in control, p<0.0001) and a lower average cross-sectional area of remaining terminal bronchioles (110mm² vs 178 in fBOS vs 175 in control).In conclusion: in RAS lungs, both airways>1mm and terminal bronchioles shrink and/or disappear while in fBOS lungs, the airways become obstructed. There was no difference in terminal bronchioles between fBOS and normal lung. ER -