Can a pressure-limited V-A shunt for obstructive uropathy really protect the kidney?

BackgroundIn our fetal lamb model of lower urinary tract obstruction, a valved shunt preserves bladder function. This study investigates the effects on renal 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 renal histology in 4 groups: group A—OU without shunt, group B—low-pressure shunt (15–54 mmH2O), group C—high-pressure shunt (95–150 mmH2O). Shunts were inserted 3 weeks post-obstruction. Group D were normal controls.ResultsWe delivered 32 fetuses from 23 ewes: 13 fetuses in group A (9 survived), 6 fetuses in group B (5 survived), 7 fetuses in group C (5 survived), and 6 fetuses in group D. Histologically, we found renal tubular distention, vacuolated degeneration of tubular epithelial cells in 7 lambs, and cyst formation in 4 lambs in group A. There was renal tubular distention in two lambs, and cyst formation in one lamb in both groups B and C, with vacuolated degeneration of tubular epithelial cells observed in all but 1 lamb in each group.ConclusionsV-A shunting prevents multicystic dysplastic kidney (MCDK). Some lambs have renal tubular distention and vacuolated degeneration of renal tubular epithelial cells.