Objectives: As a less invasive alternative to bronchoalveolar lavage (BAL), bronchoscopic microsampling (BMS) was developed to identify molecules present in the epithelial lining fluid (ELF) of the distal airways. Here, we evaluated the utility of BMS for serial collection of ELF in a canine lung transplant model.
Methods: ELF was collected hourly by BMS up to 5 hours after reperfusion in a canine left lung transplant model. Tumor necrosis factor (TNF)-α levels in ELF were measured using an enzyme-linked immunosorbent assay and were compared with those in BAL fluid.
Results: Serial collection of ELF by BMS in graft lungs was possible without adverse effects. However, the partial pressure of oxygen was markedly decreased because of ischemia-reperfusion lung injury. Probe ELF absorption ranged from 1-18 µL. TNF-α expression was significantly elevated and detected for 5 hours after reperfusion, whereas it was very low in the sham-operated group (p < 0.05). TNF-α concentration in BAL fluid was less than one-hundredth of that in ELF.
Conclusions: BMS was safe and effective for serial ELF collection in grafted lungs. Temporal changes in TNF-α corresponded with ischemia-reperfusion lung injury. This is the first study to adopt BMS to elucidate pulmonary function after lung transplantation.