Induction of heme oxygenase-1 in kidneys during ex vivo warm perfusion.
BACKGROUND
Reperfusion injury plays a pivotal role in the occurrence of delayed graft function and chronic rejection. Heme oxygenase-1 (HO-1), an inducible heat shock protein, is known to have cytoprotective effects against reperfusion injury. We report on the potential for ex vivo induction of HO-1 expression during acellular warm perfusion of canine kidneys, using cobalt protoporphyrin (CoPP) as an HO-1 inducer and zinc protoporphyrin as an HO-1 inhibitor.


METHODS
Canine kidneys were used to evaluate HO-1 increase after exposure to warm ischemia (WI), hypothermic perfusion (mechanical perfusion [MP], 4 degrees C), warm perfusion (exsanguineous metabolic support [EMS], 32 degrees C), or various combinations.


RESULTS
WI alone, MP, or EMS with or without WI, had no effect on HO-1 activity. However, the presence of CoPP during EMS perfusion resulted in a significant increase in kidney HO-1 activity, whereas zinc protoporphyrin reduced HO-1 activity. The presence of CoPP during MP did not induce elevated HO-1 expression. The results of our study demonstrate that sufficient metabolism supporting new protein synthesis resulting in the expression of the protective gene, HO-1, can be accomplished during an acellular near-normothermic perfusion using CoPP. Most importantly, the time required for ex vivo HO-1 induction with this method is compatible with the current time frame for which organs are preserved clinically.


CONCLUSIONS
The ability to induce HO-1 expression ex vivo eliminates the need for donor therapy to induce HO-1 increase before retrieving organs and also prevents the potential of decreasing HO-1 enzyme activity that is known to occur with temperature-mediated inhibition of oxidative metabolism during hypothermic organ storage.
Brasile
Lauren
L
Faculty of Medicine, University of Maastricht, Maastricht, The Netherlands.
Buelow
Roland
R
Stubenitsky
Bart M
BM
Kootstra
Gauke
G
D000818:Animals; D015925:Cryopreservation; D004285:Dogs; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006358:Hot Temperature; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D009926:Organ Preservation / Q000379:methods*; D010477:Perfusion; D011524:Protoporphyrins / Q000494:pharmacology
D004791:Enzyme Inhibitors; D011524:Protoporphyrins; C017803:zinc protoporphyrin; C007095:cobaltiprotoporphyrin; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1