Difference between revisions of "Pham 2014 Am J Physiol"
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{{Publication | {{Publication | ||
|title=Pham T, Loiselle D, Power A, Hickey AJ (2014) Mitochondrial inefficiencies and anoxic ATP hydrolysis capacities in diabetic rat heart. Am J Physiol [Epub ahead of print]. | |title=Pham T, Loiselle D, Power A, Hickey AJ (2014) Mitochondrial inefficiencies and anoxic ATP hydrolysis capacities in diabetic rat heart. Am J Physiol [Epub ahead of print]. | ||
|info=[http://www.ncbi.nlm.nih.gov/pubmed/24920675 PMID: 24920675] | |info=[http://www.ncbi.nlm.nih.gov/pubmed/24920675 PMID: 24920675] | ||
|authors=Pham T, Loiselle D, Power A, Hickey AJ | |authors=Pham T, Loiselle D, Power A, Hickey AJ | ||
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|tissues=Heart | |tissues=Heart | ||
|preparations=Homogenate | |preparations=Homogenate | ||
|diseases=Diabetes, Myopathy | |||
|couplingstates=LEAK, OXPHOS, ETS | |couplingstates=LEAK, OXPHOS, ETS | ||
|substratestates=CI, CI+II, ROX | |substratestates=CI, CI+II, ROX | ||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
}} | }} |
Revision as of 12:42, 8 July 2014
Pham T, Loiselle D, Power A, Hickey AJ (2014) Mitochondrial inefficiencies and anoxic ATP hydrolysis capacities in diabetic rat heart. Am J Physiol [Epub ahead of print]. |
Pham T, Loiselle D, Power A, Hickey AJ (2014) Am J Physiol
Abstract: As approximately 80% of diabetics die from heart failure, understanding diabetic cardiomyopathy is crucial. Mitochondria occupy 35-40% of mammalian the cardiomyocyte volume, supply 95% of the hearts' ATP, and diabetic heart mitochondria show impaired structure, arrangement and function. We predict that bioenergetic efficiencies are present in diabetic heart mitochondria; therefore we explored mitochondrial proton and electron handling by linking oxygen flux within streptozotocin (STZ)-induced-diabetic Sprague-Dawley rat heart tissues, to steady-state ATP synthesis, Reactive Oxygen Species (ROS) production, and mitochondrial membrane potential (ΔΨ). By coupling high-resolution respirometers with purpose-built fluorometers, we followed Magnesium Green (ATP synthesis), Amplex Ultra Red (ROS production), and safranin-O (ΔΨ). Relative to Control rats, the mass-specific respiration of STZ-diabetic hearts was depressed in oxidative phosphorylating (OXPHOS) states. Steady-state ATP synthesis capacity was almost a third lower in STZ-diabetic heart and relative to O2 flux, this equates to an estimated 12% depression in OXPHOS efficiency. However, with anoxic transition, STZ-diabetic and Control heart tissues showed similar ATP hydrolysis capacities through reversal of the F1/F0 ATP-synthase. STZ-diabetic cardiac mitochondria also produced more net ROS relative to oxygen flux (ROS/O) in OXP. While ΔΨ did not differ between groups, the time to develop ΔΨ with the onset of OXPHOS was protracted in STZ-diabetic mitochondria. ROS/O is higher in life-like OXPHOS states and potential delays in the time to develop ΔΨ may delay ATP synthesis with inter-beat fluctuations in ADP concentrations. Whereas diabetic cardiac mitochondria produce less ATP in normoxia, they consume as much ATP in anoxic infarct-like states. • Keywords: Diabetic cardiomypathy, Anoxia, Efficiency, Mitochondria, Oxidative phosphorylation, Safrann, Amplex Red
• O2k-Network Lab: NZ Auckland Hickey AJ
Labels: MiParea: Respiration
Pathology: Diabetes, Myopathy
Organism: Rat Tissue;cell: Heart Preparation: Homogenate
Coupling state: LEAK, OXPHOS, ETS"ETS" is not in the list (LEAK, ROUTINE, OXPHOS, ET) of allowed values for the "Coupling states" property.
HRR: Oxygraph-2k