Mitochondrial defects and heterogeneous cytochrome c release after cardiac cold ischemia and reperfusion.
Mitochondria play a critical role in myocardial cold ischemia-reperfusion (CIR) and induction of apoptosis. The nature and extent of mitochondrial defects and cytochrome c (Cyt c) release were determined by high-resolution respirometry in permeabilized myocardial fibers. CIR in a rat heart transplant model resulted in variable contractile performance, correlating with the decline of ADP-stimulated respiration. Respiration with succinate or N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride (substrates for complexes II and IV) was partially restored by added Cyt c, indicating Cyt c release. In contrast, NADH-linked respiration (glutamate+malate) was not stimulated by Cyt c, owing to a specific defect of complex I. CIR but not cold ischemia alone resulted in the loss of NADH-linked respiratory capacity, uncoupling of oxidative phosphorylation and Cyt c release. Mitochondria depleted of Cyt c by controlled hypoosmotic shock provided a kinetic model of homogeneous Cyt c depletion. Comparison to Cyt c control of respiration in CIR-injured myocardial fibers indicated heterogeneity of Cyt c release. The complex I defect and uncoupling correlated with heterogeneous Cyt c release, the extent of which increased with loss of cardiac performance. These results demonstrate a complex pattern of multiple mitochondrial damage as determinants of CIR injury of the heart.
Kuznetsov
Andrey V
AV
Department of Transplant Surgery, D. Swarovski Research Laboratory, University Hospital Innsbruck, A-6020 Innsbruck, Austria.
Schneeberger
Stefan
S
Seiler
Rüdiger
R
Brandacher
Gerald
G
Mark
Walter
W
Steurer
Wolfgang
W
Saks
Valdur
V
Usson
Yves
Y
Margreiter
Raimund
R
Gnaiger
Erich
E
D000818:Animals; D015925:Cryopreservation; D045304:Cytochromes c / Q000378:metabolism*; D042967:Electron Transport Complex I / Q000378:metabolism; D006321:Heart / Q000503:physiopathology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008929:Mitochondria, Heart / Q000378:metabolism*; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000503:physiopathology; D010101:Oxygen Consumption; D051381:Rats; D011917:Rats, Inbred Lew
D045304:Cytochromes c; D042967:Electron Transport Complex I