Normothermic versus hypothermic ex vivo flush using a novel phosphate-free preservation solution (AQIX) in porcine kidneys.
BACKGROUND
The initial flush of an organ is important to remove any cellular components from the microcirculation before storage. The aim of this study was to assess graft function after an ex vivo warm flush with a novel non-phosphate buffered preservation solution AQIX RS-I (AQIX) compared with a traditional cold flush.


METHODS
Porcine kidneys were either warm-flushed with AQIX RS-I at 30°C, or cold-flushed at 4°C with University of Wisconsin solution (UW) or hyperosmolar citrate (HOC) preservation solution at a pressure of 100 cmH2O (n = 6). Renal function was measured ex vivo by perfusing the organs with autologous blood at 37°C on an isolated organ perfusion system.


RESULTS
The AQIX group flushed significantly quicker than the cold stored groups (22 ± 1.8 versus UW 4.9 ± 1.6 versus HOC 10 ± 1.6 mL/min/100g; P = 0.001) and gained less weight than the UW group (19 ± 2.9 versus UW 30 ± 3.4 versus HOC 21% ± 7.7%; P = 0.025). The AQIX group also had superior acid-base homeostasis. Functional results, histologic analysis, and ADP: ATP levels were comparable between the groups.


CONCLUSIONS
Flushing kidneys with AQIX at 30°C cleared the renal microcirculation of blood more rapidly without any detrimental effects when compared to traditional cold flushing with UW or HOC at 4°C. Warm initial flushing has potential to be developed as part of normothermic renal preservation techniques.
Kay
Mark D
MD
Department of Infection, Immunity, and Inflammation, Transplant Group, University of Leicester, Leicester General Hospital, Leicester, United Kingdom.
Hosgood
Sarah A
SA
Harper
Simon J F
SJ
Bagul
Atul
A
Waller
Helen L
HL
Nicholson
Michael L
ML
D000136:Acid-Base Equilibrium / Q000502:physiology; D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D002951:Citrates / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D007036:Hypothermia, Induced / Q000379:methods*; D007328:Insulin / Q000494:pharmacology; D007668:Kidney / Q000098:blood supply / Q000502:physiology*; D016030:Kidney Transplantation; D008833:Microcirculation / Q000502:physiology; D019188:Organ Preservation Solutions / Q000494:pharmacology*; D010710:Phosphates; D011887:Raffinose / Q000494:pharmacology; D015427:Reperfusion Injury / Q000517:prevention & control*; D018454:Spouses; D013696:Temperature
D002951:Citrates; D007328:Insulin; D019188:Organ Preservation Solutions; D010710:Phosphates; C055206:University of Wisconsin-lactobionate solution; D000244:Adenosine Diphosphate; D000493:Allopurinol; D000255:Adenosine Triphosphate; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose