Flush Perfusion, Preservation and Reperfusion Effects in Lung Transplantation: Light Microscopic and Ultrastructural Study

ABSTRACT

This study was undertaken to investigate the morphologic changes following flushing, preservation and reperfusion procedures in a canine lung allotransplantation model. Donor lungs were flushed with modified Euro-Collins (MEC) solution, low potassium dextran glucose (LPDG) solution or University of Wisconsin (UW) solution, then stored at 10oC for 20 hours. Light microscopic and electron microscopic features of the lungs were examined after flushing, preservation and 2 hours after reperfusion. After flushing light microscopy showed focal mild alveolar collapse and interstitial edema. After preservation the lung tissue showed multiple foci of alveolar collapse, consolidation, and alveolar epithelial cell damage. After reperfusion the lung tissue showed diffuse alveolar collapse, consolidation and many destroyed cellular debris in the alveolar lumina. After flushing electron microscopy showed focal alveolar collapse and mild swelling of type I epithelial cells. After preservation both type I epithelial cells and endothelial cells were swollen and destroyed focally. Some type I epithelial cells were detached from the basal lamina. The endothelial cells showed luminal protrusion of tactile-like structure and vacuoles of the cytoplasm. After reperfusion the lung tissue showed fibrin material in the alveoli, prominent type I epithelial cell swelling with fragmented cytoplasmic debris and marked endothelial cell swelling with vacuoles or tactile-like projections. The alveolar macrophages showed active phagocytosis. After preservation scanning electron microscopic examination of the pulmonary arteries showed multiple patchy areas of swelling or conglomerated lesions in the inner surface of the pulmonary arteries. In conclusion, the ultrastructural changes associated with flushing were mild in severity, the donor lungs were injured during the preservation, and further damage occurred during the reperfusion.