Effect of Remote Ischemic Conditioning on Local Graft Metabolism after Renal Transplantation from a Brain Dead Donor - An Experimental Study

Purpose: Small pediatric recipients receiving adult size kidneys from brain dead donors are at increased risk of vascular thrombosis and delayed graft function (DGF). We evaluated the local renal metabolic changes after graft reperfusion and the effect of remote ischemic conditioning (rIC) by use of microdialysis in a porcine DGF model. Methods: Kidneys were recovered in brain dead pigs after 21h46min mean cold ischemia time. Recipient pigs were nephrectomized and randomized to rIC or control (15 kg, n=8 in each group). A control group of large recipient pigs was included as well (60 kg, n=8). The rIC protocol was four 5-minutes distal abdominal aorta clamping and unclamping cycles. Microdialysis catheters were placed cortically and extracapsularly. Follow-up was 10 hours from graft reperfusion, with hourly microdialysis samples. Results: Cortical glucose developed significantly different (p=0.038) in the two small recipient groups, particularly in the middle of the observation period, with a higher glucose level after rIC. Glutamate decreased after reperfusion, with a systematic difference between groups (p=0.0075), due to lower levels in rIC pigs the first 4 h after reperfusion. Local lactate and glycerol showed high levels after reperfusion and decreased during follow up, with no differences between groups. Conclusion: A gradual normalization of the local metabolism after reperfusion was demonstrated in all groups by use of microdialysis. rIC seemed to induce a faster metabolic recovery, this was significant for glutamate and glucose in the early hours after graft reperfusion and may be relevant for organ protection.