Pressure limited vesico-amniotic shunt allows normal lung growth in a fetal lamb model of obstructive uropathy

BackgroundIn our fetal lamb model of lower urinary tract obstruction, a pressure limited shunt preserves bladder function and renal development. This study investigates the effects on pulmonary histology.MethodsWe created obstructive uropathy (OU) in 60-day gestation fetal lambs, ligating the urethra and urachus, and delivering them at term (130-145 days). We compared pulmonary histology in 4 groups: group A, OU without shunt; group B, pressure limited shunt; group C, non-valved shunt. Shunts were inserted 3 weeks post-obstruction. Group D were normal controls.ResultsWe compared 27 fetuses: 7 fetuses in group A, 4 fetuses in group B, 2 fetuses in group C, and 14 fetuses in group D. There was no significant difference in lung volume in any group. In group A, there were some areas of atelectasis and incomplete alveolar formation histologically. The alveoli in group A lambs lungs had a predominance of type II cells, whereas group B lambs lungs were lined by type I epithelial cells and were essentially indistinguishable from controls.ConclusionsThis study suggests that using a pressure-limited vesico-amniotic shunt in OU may preserve the renal tract and the lungs.