To Örebro University

BACKGROUND: Renal ischemia-reperfusion injury is a common cause of acute kidney injury in intensive care and surgery. Recently, novel organic mononitrites of 1,2-propanediol (PDNO) were synthesized and shown to rapidly and controllably deploy nitric oxide in the circulation when administered intravenously. We hypothesized that intravenous infusion of PDNO during renal ischemia reperfusion would improve post-ischemic renal function and microcirculation.

METHODS: Sixteen sheep were anesthetized, mechanically ventilated, and surgically instrumented. The left renal artery was clamped for 90 min, and the effects of ischemia were studied for a total of 8 h. Fifteen minutes prior to the release of the clamp, intravenous infusions of PDNO (n = 8) or vehicle (1,2 propanediol + inorganic nitrite, n = 8) were initiated (180 nmol/kg/min for 30 min, thereafter 60 nmol/kg/min for the remainder of the experiment).

RESULTS: Renal artery blood flow, cortical and medullary perfusion, and diuresis and creatinine clearance decreased in the left kidney post ischemia. However, in the sheep treated with PDNO, diuresis and creatinine clearance in the left kidney were significantly higher post ischemia compared to vehicle-treated animals (1.7 ± 0.5 vs 0.7 ± 0.3 ml/kg/h, p = 0.04 and 7.5 ± 2.1 vs 1.7 ± 0.6 ml/min, p = 0.02, respectively). Left renal medullary perfusion and oxygen uptake were higher in the PDNO group (73 ± 9 vs 37 ± 5% of baseline, p = 0.004 and 2.6 ± 0.4 vs 1.6 ± 0.3 ml/min, p = 0.02, respectively). PDNO significantly increased renal oxygen consumption and reduced the oxygen utilization for sodium reabsorption (p = 0.03 for both). Mean arterial blood pressure was significantly reduced by PDNO (83 ± 3 vs 94 ± 3 mmHg, p = 0.02) but was still within normal limits. Total renal blood flow was not affected, and there were no signs of increased blood methemoglobin concentrations or tachyphylaxis.

CONCLUSIONS: The novel nitric oxide donor PDNO improved renal function after ischemia. PDNO also prevented the persistent reduction in medullary perfusion during reperfusion and improved renal oxygen utilization without severe side effects.