Oxygenated Kidney Preservation Techniques

Abstract

Improving preservation techniques to minimize injury is of particular importance in organs from marginal donors. Since the introduction of transplantation and routine use of hypothermic temperatures for kidney preservation, there has been much debate on whether it is necessary to add oxygen to support the low level of metabolism under these conditions. Supplementing the kidney with oxygen during hypothermic preservation is not common practice. However, there is evidence to support its application. Oxygen can be added by various techniques such as retrograde persufflation whereby filtered and humidified oxygen is bubbled through the vasculature; under hyperbaric conditions using specialized pressurized chambers; during hypothermic machine perfusion; with the addition of oxygen carriers; and under normothermic conditions. Evidence suggests that oxygenation is particularly beneficial in restoring cellular levels of adenosine triphosphate after kidneys have been subjected to warm or cold ischemic injury. However, under normal conditions, the benefits are less convincing, but the evidence is insufficient to draw any conclusions. This overview explores the ways in which oxygen can be administered during preservation in experimental and clinical models of kidney transplantation.

Comparison of Aerobic Preservation by Venous Systemic Oxygen Persufflation or Oxygenated Machine Perfusion of Warm-Ischemia-Damaged Porcine Kidneys

“…It has been shown that VSOP represents the best method of fully oxygenating an entire human-sized organ when compared with CS, MP, and OMP [11,29,30,31]. Also compared to other techniques, VSOP is a relatively inexpensive and simple technique, with favorable reported results [8,11,32,33,34]. Some drawbacks of VSOP, however, are the potential formation of gaseous emboli and the low potential for waste removal and nutrient supply when compared to MP and OMP [11,35].…”

Mechanistic Analysis of Nonoxygenated Hypothermic Machine Perfusion’s Protection on Warm Ischemic Kidney Uncovers Greater eNOS Phosphorylation and Vasodilation

“…These MP effects were concomitant to increases in cortical microcirculation after unclamping in vivo. NO synthesis being oxygen-dependent, future studies should investigate this pathway during oxygenated MP, which previously proved more protective than standard MP (51)(52)(53). Moreover, pharmaceutical strategies directed at this pathway could be developed to improve both static and dynamic storage.…”

New Strategies and Concepts in Organ Preservation

“…Additionally, recent investigations into cost/benefit relations have come up with the clear conclusion that a reduction of delayed graft function and the ensuing requirement for dialysis would be a pertinent denominator in favor of machine perfusion preservation. Moreover, recent discoveries in the area of perfusion mechanistics, such as low-pressure perfusion to avoid mechanical stress to the organ vasculature [40] or the need for active oxygenation in grafts from DCD suggested in the mean time [24,32,41], should be taken into account when evaluating negative reports from clinical trials undertaken with less appropriate technologies.…”

“…Adequate tissue energetics is thought to improve cellular ion and signal homeostasis during preservation, to mitigate the graft's proclivity for suffering from further tissue damage during the period of a second warm ischemia upon implantation surgery and to fuel initial function upon reperfusion [24,25]. Since the fate of an organ depends on whether cell death or regeneration prevails, autophagic processes, which seem to influence regeneration after ischemic insult, should come into the focus of organ preservation research.…”