Cold induces catalytic iron release of cytochrome P-450 origin: a critical step in cold storage-induced renal injury.
Earlier experimental studies have suggested a role for iron in cold-storage-induced organ injury. Whether the cytochrome P-450 enzymes, shown to be a source for iron in several injury models, contribute to cold-induced iron release is not known. Storage of human proximal tubular epithelial (RPTE) cells at 4 degrees C in the University of Wisconsin (UW) solution caused a significant and time-dependent increase in bleomycin-detectable iron (BDI). To identify the cellular source of BDI, RPTE cells were subfractionated and stored at 4 degrees C for 4 h. Bleomycin-detectable iron release was highest in the microsomes, next in the cytosol and none in the mitochondria. As microsomes are rich in iron-containing cytochrome P-450 enzymes, microsomes were cold stored with P-450 inhibitors, cimetidine and piperonyl butoxide. P-450 inhibitors significantly reduced cold-induced BDI release. Furthermore, cimetidine and iron chelator deferoxamine (DFO) significantly reduced cold-induced cell injury, suggesting a role for P-450-derived iron in cold-induced cell injury. In rat kidney experiments, BDI and LDH release were significantly higher in cold-stored kidneys than in control kidneys. Inclusion of cimetidine and DFO in the cold-storage solution significantly suppressed the BDI and LDH release, and reduced the ultrastructural changes. Our data demonstrate for the first time that cold-induced catalytic iron release may be at least in part of microsomal cytochrome P-450 origin, and that it participates in cold-storage-induced renal injury. In the clinical setting, sequestering free iron released during cold storage is possible and may prove to be useful in limiting organ injury.
Huang
Hong
H
Department of Medicine, University of Mississippi Medical Center, Jackson 39216-4505, USA.
Salahudeen
Abdulla K
AK
D000241:Adenosine; D000493:Allopurinol; D002384:Catalysis; D002927:Cimetidine / Q000494:pharmacology; D003080:Cold Temperature; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000378:metabolism*; D003676:Deferoxamine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione; D006801:Humans; D007328:Insulin; D007501:Iron / Q000032:analysis*; D007668:Kidney / Q000473:pathology*; D007684:Kidney Tubules / Q000187:drug effects / Q000201:enzymology; D009926:Organ Preservation / Q000009:adverse effects* / Q000379:methods*; D019188:Organ Preservation Solutions; D011887:Raffinose; D019459:Urothelium / Q000187:drug effects / Q000201:enzymology
D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D007328:Insulin; D019188:Organ Preservation Solutions; C055206:University of Wisconsin-lactobionate solution; D000493:Allopurinol; D002927:Cimetidine; D003577:Cytochrome P-450 Enzyme System; D007501:Iron; D005978:Glutathione; D003676:Deferoxamine; D000241:Adenosine; D011887:Raffinose