[Pharmacological preconditioning with sildenafil of warm ischemic kidneys]. / Precondicionamiento farmacológico con sildenafilo del riñón con isquemia normotérmica.

OBJECTIVES: To evaluate the preconditioning effect of sildenafil administered preoperatively in kidneys subjected to a period of warm ischemia (WI), hypothermic perfusion (HP) or cold storage (CS) and finally, autotransplant (AT). MATERIAL AND METHOD: We studied 6 groups of autotransplanted kidneys: no-WI-inmediate AT (Group A); 45 min of WI + immediate AT (Group B); 45 min of WI + 60 min of HP + autotransplant (Group C); 45 min of WI + 60 min of CS + autotransplant (Group D); 100 mg of oral sildenafil preoperatively + 45 min of WI + autotransplant (Group E); 100 mg of oral sildenafil preoperatively + 45 min of WI+60 min of HP + autotransplant (Group F). Belzer solution was used for HP; UW-Viaspan for CS. Inmediately after the autotransplant (reperfusion period), we recorded in real time for 60 min the values of Renal vascular Flow (RVF) and Renal Vascular Resistance (RVR). Nitric Oxide levels in the cava and renal graft vein were recorded every 15 min during the 60 min of the reperfusion-study period. Conventional & Electronic microscopy were completed after the process. RESULTS: We obtained significant higher values of RVF and lower values of RVR in sildenafil groups (E and F) in comparison to the other groups (A-D) (Table 1). NO levels were also significantly higher in groups E and F (Fig. 1). Groups A, B, E and F showed integrity of tubule and endothelium in comparison to groups C and D in the microscopic study. CONCLUSIONS: We showed a beneficious effect of sildenafil in inmediate post-transplant reperfusion hemodynamic and biochemical parameters of kidneys subjected to a critical period of warm-ischemia.

[Ischemia-reperfusion syndrome and role of preservation graft technique after laparoscopic versus open nephrectomy in a experimental model of living donor kidney transplant]. / Evaluación del síndrome isquemia-reperfusión y papel de la preservación del injerto en la extracción renal laparoscópica versus abierta en un modelo experimental porcino de donante vivo.

INTRODUCTION: Delayed graft function alter living donor transplantation is a subject of debate. Delayed graft function can be partially explained by renal ischemia-reperfusion injury, when severe is associated with decreased graft survival. In this experimental living donor model study, we analyze the hemodynamic, histological and biochemical effects of laparoscopic nephrectomy. We also, analyze the effect of a pulsatile machine perfusion for kidney preservation during cold ischemia time. MATERIAL AND METHODS: Twenty large-white pigs (average weight 40-45 kgrs) were divided in 4 experimental groups: Group A: Laparoscopic nephrectomy+ immediate graft perfusion in pulsatile vacuum pump+autotransplant Group B: Laparoscopic nephrectomy+ immediate graft perfusion by gravity+autotransplant Group C: Open nephrectomy+immediate graft perfusion in pulsatile vacuum pump+autotransplant Group D: Open nephrectomy+ immediate graft perfusion by gravity+autotransplant Both laparoscopic and open nephrectomy were completed transperitoneally according to standardized technique. Hypothermic perfusion was done in a system designed in our lab. RESULTS: We observed a decreased renal artery flow in kidneys procured laparoscopically compared to open nephrectomy. We found an artery flow recovery during the first 60 minutes after revascularization. Renal machine perfusion during cold ischemia time seems to have no beneficial effect, but shows a deleterious effect on hemodynamic event for renal transplantation. Lower plasma nitric oxide level is observed in kidneys obtained by laparoscopy compared with open surgical technique. And finally, we also found higher histological damage in proximal tubular and endothelial cell, in kidneys obtained by laparoscopy compared with open surgery. CONCLUSIONS: In our experience: Laparoscopic nephrectomy versus open nephrectomy produces, in a model of living donor transplant, a lower value or renal blood flow and a higher value of renal vascular resistanse. These hemodynamic findings tend to normalize by 60 min after the reperfusion. A lower blood concentration of nitric oxide after the transplant was detected in laparoscopic group Vs open surgery group.