Options to improve the quality of kidney grafts from expanded criteria donors experimental study

There is a worldwide discrepancy between the number of donors and the number of organs needed for transplantation, leading to certain expansion of criteria, resulting in acceptance of donor organs. This means that organs with worse parenchymal qualities may be harvested for transplantation. One possibility, how to ameliorate the quality of these organs, is to change the concept of their preservation during cold ischemia or even after sudden circulatory arrest, prior to the collection of the organ itself. The goal of our experimental study was to try to improve organ quality from these marginal donors.

In the first part of our experimental study, we tested retrograde oxygen persufflation (ROP) in preservation of ischemically damaged kidney grafts. In ten animals (domestic pig), we compared standard intra-arterial perfusion of the grafts using cooled perfusion solution (N=5), with a retrograde oxygen persufflation method (N=5). The main criterion for evaluation was the histopathological analysis of renal parenchyma after transplantation of the kidney graft. In the second part of our experimental study, again using an animal model of an ischemic kidney (laboratory rabbit), we compared machine perfusion of the kidney graft with routinely used perfusion by hydrostatic pressure. For evaluation, we added another two criteria - the volume of perfusate that flowed through the graft and the temperature drop during perfusion.

In the first part of the study, we proved the ability of ROP to preserve and even ameliorate the quality of ischemically damaged kidney grafts. Results of histopathological analysis of samples taken during ROP were without statistically significant difference in comparison with those taken during standard intra-arterial perfusion. In the second part of the study, we observed a significant difference in maximal flow rate measured during perfusion of the kidney grafts, favoring mechanical perfusion over perfusion using hydrostatic pressure (p=0.004). The same situation was seen with the drop of temperature measured in the parenchyma of the grafts (p<0.001). Finally, histopathological evaluation of the renal parenchyma found better washing out of blood particles from the capillaries during mechanical perfusion (p=0.005).

The presented results of our experimental studies establish that alternative methods of preservation during cold ischemia and before removal of kidney grafts from the donor may be beneficial for its function after transplantation. We believe that these methods may be suitable especially for so-called marginal grafts from extended criteria donors.Key words: transplantation donors after circulatory death controlled organ perfusion in situ perfusion retrograde oxygen persufflation.