VASOACTIVE-INTESTINAL-PEPTIDE ENHANCES LUNG PRESERVATION

The outcome of lung transplantation is often dependent on the quality of the donor lungs. To explore a way to improve lung preservation, vasoactive intestinal peptide (VIP) was added to pneumoplegic solutions. The 4 solutions tested were Krebs solution, Krebs solution with VIP, University of Wisconsin solution, and the University of Wisconsin solution with VIP. The lungs of 8 male Sprague-Dawley rats were flushed and stored in these solutions for 24 hr. At regular intervals, tissue was sampled and examined by light, scanning, and transmission electron microscopy. Casts of the vasculature were made after 4 hr and viewed by a scanning electron microscope. Lungs appeared well preserved by light microscopy at all intervals. Although inflammatory cells around arteries, arterial constriction, bronchiolar epithelial detachment, peribronchiolar edema, and alveolar size inhomogeneity were greater with time, there was no significant difference among the 4 groups by light microscopy. Scanning microscopy of tissue at 24 hr confirmed the information found on light microscopy but did not allow separation of the groups. The vascular casts showed that edema around large vessels was less in the lungs treated with VIP (P<0.01). Transmission electron microscopy showed that lungs stored in the solutions with VIP had significantly more normal-shaped mitochondria, less mitochondrial edema, less distortion of mitochondrial cristae, thinner basal lamina, and less aggregation of nuclear chromatin at most intervals sampled after 4 hr. We conclude that VIP added to certain pneumoplegic solutions improves the ultrastructure of rat lung stored in the cold for up to 24 hr. VIP may be an important additive to pneumoplegic solutions to improve preservation of lung before transplantation.