title: Naked small interfering RNA of caspase-3 in preservation solution and autologous blood perfusate protects isolated ischemic porcine kidneys.
abstract: BACKGROUND
  Ischemia-reperfusion injury (IRI) plays key roles in graft viability and posttransplantation function. Caspase-3 associated with apoptosis and inflammation is up-regulated by IRI. We propose that naked small interfering RNA (siRNA) targeting caspase-3 may prevent IRI and improve kidney preservation.
  
  
  METHODS
  Porcine kidneys were retrieved after 10-min warm ischemia and flushed with 500 mL hyperosmolar citrate. Caspase-3 siRNA was administered directly into the renal artery in hyperosmolar citrate solution (3 μg/ml) with the renal vein clamped and into autologous blood (0.15 μg/ml), both of which were stored for 24 hr on ice. The kidneys were reperfused with oxygenated autologous blood for 3 hr on an isolated organ perfusion system to assess renal function.
  
  
  RESULTS
  In the siRNA-treated group, the expression of 32-kDa caspase-3 precursor and 17-kDa active subunit was down-regulated by 30% and 56%, respectively, with 40% reduction in active caspase-3+ cells. Consequently, apoptotic cells in the renal cortex were significantly decreased by 47%, whereas inflammatory cells were only marginally reduced by 26%. Caspase-3 siRNA also doubled oxygen consumption and significantly neutralized perfusate pH. Renal blood flow was gradually increased from 5 min to 3 hr by caspase-3 siRNA and marginally improved at the end of 3-hr reperfusion by 45%.
  
  
  CONCLUSIONS
  The administration of caspase-3 siRNA directly into the kidney and hemoperfusate during cold preservation improved IRI with reduced caspase-3 and apoptosis, and better renal oxygenation and acid-base homeostasis. This proof of principle experiment using a novel siRNA therapy in large animal organs provides valuable data for human kidney transplantation.
authors.affiliation: Transplant Group, Department of Immunity, Infection and Inflammation, University of Leicester, Leicester General Hospital, Gwendolen Road, Leicester, United Kingdom. by5@le.ac.uk
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Hosgood
authors.forename: Michael L
authors.initials: ML
authors.lastname: Nicholson
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000235:genetics* / Q000378:metabolism; D061945:Caspase Inhibitors; D015925:Cryopreservation / Q000379:methods*; D006085:Graft Survival; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D016030:Kidney Transplantation / Q000473:pathology; D023421:Models, Animal; D019188:Organ Preservation Solutions / Q000494:pharmacology / Q000627:therapeutic use*; D010101:Oxygen Consumption / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology / Q000627:therapeutic use*; D015424:Reperfusion; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013552:Swine; D052096:Warm Ischemia
chemical_list: D061945:Caspase Inhibitors; D019188:Organ Preservation Solutions; D034741:RNA, Small Interfering; D053148:Caspase 3