Is solitary kidney really more resistant to ischemia? An experimental canine study.

Purpose: To our knowledge there are no evidence-based medicine data to date to critically judge the vulnerability of a solitary kidney to warm ischemia compared to paired kidneys.

Materials And Methods: Ten dogs were exposed to open right nephrectomy to create a solitary kidney model (group 1). Ten dogs with both kidneys were considered group 2. All dogs underwent warm ischemia by open occlusion of the left renal artery for 90 minutes. Dogs were sacrificed at different intervals (3 days to 4 weeks). All dogs were reevaluated by renogram before sacrifice and histopathology of the investigated kidney. The proinflammatory markers CD95 and tumor necrosis factor-α were assessed using real-time polymerase chain reaction.

Results: In group 1 clearance decreased by 20% at 1 week but basal function was regained starting at week 2. In group 2 clearance decreased more than 90% up to week 2. Recovery started at week 3 and by 4 weeks there was a 23% clearance reduction. Histopathological examination in group 1 revealed significant tubular necrosis (60%) at 3 days with regeneration starting at 1 week. In group 2 there was more pronounced tubular necrosis (90%) with regeneration starting at 2 weeks. The expression of proinflammatory markers was up-regulated in each group with higher, more sustained expression in group 2.

Conclusions: Solitary kidney in a canine model is more resistant to ischemia than paired kidneys based on radiological, pathological and genetic evidence.