Implication of mitochondrial dysfunction and cell death in cold preservation--warm reperfusion-induced hepatocyte injury.
Cold ischemia--warm reperfusion (CI/WR) injury of liver transplantation involves hepatocyte cell death, the nature and underlying mechanisms of which remain unclear. Isolated hepatocytes and isolated perfused livers were used to determine the prevalence of necrosis and apoptosis as well as mitochondrial dysfunction. In isolated cells, propidium iodide and Hoechst 33342 staining showed a cold-storage, time-dependent increase in necrosis, whereas apoptosis was minimal even after 48 h of hypothermia. Nonetheless, a progressive loss of mitochondrial membrane potential was observed. Translocation of mitochondrial cytochrome c toward microsomes occurred within 24 h of CI/WR, with cytochrome c reaching the cytosol later. Mitochondria isolated from whole livers subjected to CI/WR also display reduced metabolic parameters and increased susceptibility to swelling. These events are associated with increased activity of major initiator (caspase 9) and effector (caspase 3) caspases. The results demonstrate that CI/WR induces mitochondrial dysfunction in isolated cells and in the whole organ; only in the latter is that sufficient to trigger the classical mitochondrial pathway of apoptosis. Our study also provides evidence for the involvement of endoplasmic reticulum stress in CI/WR hepatocyte injury. Combined protection of mitochondria and endoplasmic reticulum may thus represent an innovative therapeutic avenue to enhance liver graft viability and functional integrity.
Duval
Marjolaine
M
Département de Pharmacologie et Groupe d'étude sur les protéines membranaires, Faculté de Médecine, Université de Montréal, P.O. Box 6128, Downtown Station, Montréal, QC H3C 3J7, Canada.
Plin
Catherine
C
Elimadi
Aziz
A
Vallerand
Diane
D
Tillement
Jean-Paul
JP
Morin
Didier
D
Haddad
Pierre S
PS
D000241:Adenosine; D000493:Allopurinol; D000818:Animals; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D003080:Cold Temperature; D045304:Cytochromes c / Q000378:metabolism; D005978:Glutathione; D022781:Hepatocytes / Q000473:pathology* / Q000502:physiology; D066298:In Vitro Techniques; D007328:Insulin; D008099:Liver / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D016031:Liver Transplantation; D008297:Male; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D008933:Mitochondrial Swelling; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D011887:Raffinose; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000473:pathology / Q000503:physiopathology*
D007328:Insulin; D019188:Organ Preservation Solutions; C055206:University of Wisconsin-lactobionate solution; D000493:Allopurinol; D045304:Cytochromes c; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose