title: Phosphodiesterase-5 inhibition prevents postcardiopulmonary bypass acute kidney injury in swine.
abstract: BACKGROUND
  Acute kidney injury after cardiac surgery is common, has no effective treatments, and is associated with adverse outcomes. The aim of this study was to determine whether administration of the phosphodiesterase-5 inhibitor sildenafil citrate (SDF) would prevent the development of post-cardiopulmonary bypass (CPB) acute kidney injury in swine.
  
  
  METHODS
  Adult pigs (n = 8 per group) were randomized to undergo sham procedure, CPB, or CPB plus administration of SDF, with recovery and reassessment at 24 hours.
  
  
  RESULTS
  Cardiopulmonary bypass resulted in a significant reduction in creatinine clearance relative to sham pigs (mean difference CPB versus sham, -47.9 mL/min; 95% confidence interval [CI]: -93.7 to -2.2; p = 0.039). This was prevented by the administration of SDF during CPB (mean difference CPB+SDF versus CPB, +55.6 mL/min; 95% CI: +6.5 to +104.7; p = 0.024). Cardiopulmonary bypass also resulted in a significant rise in the urinary biomarker interleukin-18 compared with sham procedures (mean difference 209.3 pg/mL; 95% CI: 120.6 to 298.1; p < 0.001) that was prevented by SDF administration. Post-CPB kidney injury was associated with vascular endothelial injury and dysfunction, reduced nitric oxide bioavailability, medullary hypoxia, cortical adenosine triphosphate depletion, inflammation, and evidence of proximal tubule epithelial cell stress manifest as phenotypic change. Administration of SDF to CPB pigs preserved nitric oxide bioavailability and prevented endothelial dysfunction, regional hypoxia, inflammation, and tubular changes.
  
  
  CONCLUSIONS
  In this model, phosphodiesterase-5 inhibition using SDF prevented post-CPB acute kidney injury by the preservation of nitric oxide bioavailability, and warrants evaluation as a renoprotective agent in clinical trials.
authors: Bristol Heart Institute, University of Bristol, Bristol Royal Infirmary, Bristol, United Kingdom.
authors: Nishith N
authors: NN
authors: Patel
authors: Hua
authors: H
authors: Lin
authors: Tibor
authors: T
authors: Toth
authors: Ceri
authors: C
authors: Jones
authors: Paramita
authors: P
authors: Ray
authors: Gavin I
authors: GI
authors: Welsh
authors: Simon C
authors: SC
authors: Satchell
authors: Philippa
authors: P
authors: Sleeman
authors: Gianni D
authors: GD
authors: Angelini
authors: Gavin J
authors: GJ
authors: Murphy
mesh_terms: D058186:Acute Kidney Injury / Q000517:prevention & control*; D000818:Animals; D015415:Biomarkers; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D005260:Female; D009569:Nitric Oxide / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000032:analysis; D052250:Nitric Oxide Synthase Type III / Q000032:analysis; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D013552:Swine
chemical_list: D015415:Biomarkers; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D009569:Nitric Oxide; D000068677:Sildenafil Citrate; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III