Oxidative capacity in failing hearts.
Although high-energy phosphate metabolism is abnormal in failing hearts [congestive heart failure (CHF)], it is unclear whether oxidative capacity is impaired. This study used the mitochondrial uncoupling agent 2,4-dinitrophenol (DNP) to determine whether reserve oxidative capacity exists during the high workload produced by catecholamine infusion in hypertrophied and failing hearts. Left ventricular hypertrophy (LVH) was produced by ascending aortic banding in 21 swine; 9 animals developed CHF. Basal myocardial phosphocreatine (PCr)/ATP measured with 31P NMR spectroscopy was decreased in both LVH and CHF hearts (corresponding to an increase in free [ADP]), whereas ATP was decreased in hearts with CHF. Infusion of dobutamine and dopamine (each 20 microg. kg-1. min-1 iv) caused an approximate doubling of myocardial oxygen consumption (MVO2) in all groups and decreased PCr/ATP in the normal and LVH groups. During continuing catecholamine infusion, DNP (2-8 mg/kg iv) caused further increases of MVO2 in normal and LVH hearts with no change in PCr/ATP. In contrast, DNP caused no increase in MVO2 in the failing hearts; the associated decrease of PCr/ATP suggests that DNP decreased the mitochondrial proton gradient, thereby causing ADP to increase to maintain adequate ATP synthesis.
Gong
Guangrong
G
Department of Medicine, Cardiovascular Division, University of Minnesota Medical School, Mayo Mail Code 508, UMHC, Minneapolis, MN 55455, USA.
Liu
Jingbo
J
Liang
Peihua
P
Guo
Tao
T
Hu
Qingsong
Q
Ochiai
Ko
K
Hou
Mingxiao
M
Ye
Yun
Y
Wu
Xiaoyun
X
Mansoor
Abdul
A
From
Arthur H L
AH
Ugurbil
Kamil
K
Bache
Robert J
RJ
Zhang
Jianyi
J
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003326:Coronary Circulation; D004195:Disease Models, Animal; D006333:Heart Failure / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D009682:Magnetic Resonance Spectroscopy; D008928:Mitochondria / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D010101:Oxygen Consumption; D010725:Phosphocreatine / Q000378:metabolism; D011522:Protons; D034421:Sus scrofa
D011522:Protons; D010725:Phosphocreatine; D000255:Adenosine Triphosphate