Mucociliary function in autotransplanted, allotransplanted, and sleeve resected lungs

Tracheobronchial mucociliary function in dogs that underwent left upper sleeve lobectomy was compared with that of dogs that underwent left lung autotransplantation or allotransplantation (n = 5 each). Proximal airway clearance was measured by observing the movement of carbon particles through a bronchoscope. Preoperative and postoperative clearance rates for the right lungs in these dogs were unchanged. Although preoperative clearance rates in the transplanted left lungs were comparable with those of the right lungs, these left lungs were unable to clear the carbon particles during a 15-minute observation period 3 weeks postoperatively. In contrast, preoperative and postoperative clearance rates for the dogs that underwent sleeve resection were unchanged for both lungs. Mucus rigidity was studied by microrheometry and was found to be significantly increased postoperatively for samples collected from the autotransplanted and allotransplanted lungs than for samples collected from the untreated right lungs. These changes in mucus were noted for forces representing both normal ciliary beat and coughing. Viscoelastic properties of mucus were not significantly altered after sleeve lobectomy. Microscopic study showed squamous cell metaplasia and relative disappearance of bronchial glands distal to the anastomosis in all transplanted lungs. These changes were less pronounced in the sleeve resected bronchi. We conclude that changes in rheologic characteristics of mucus can impair mucociliary clearance and may be related to denervation after lung transplantation. Bronchial devascularization may have an additional effect of altering mucosal structures and function in the early postoperative period after lung transplantation. These effects are avoided by preserving peribronchial tissue in sleeve resection.