Biochemical Studies of Energy Production in the Failing Human Heart
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Biochemical studies of energy production in the failing human heart. C A Chidsey, … , P E Pool, A G Morrow J Clin Invest. 1966;45(1):40-50. https://doi.org/10.1172/JCI105322. Research Article Find the latest version: https://jci.me/105322/pdf Journal of Clinical Investigation Vol. 45, No. 1, 1966 Biochemical Studies of Energy Production in the Failing Human Heart * CHARLES A. CHIDSEY,t EUGENE C. WEINBACH, PETER E. POOL, AND ANDREW G. MORROW (From the Cardiology Branch and the Clinic of Surgery, National Heart Institute, and the Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Md.) The defective myocardial performance responsi- and in vivo (6, 7), and one clinical syndrome, char- ble for the syndrome of congestive heart failure has acterized by nonthyroid hypermetabolism and re- been considered for many years to involve a bio- sulting from uncoupling of these two processes, chemical abnormality. However, identification of has been identified by Luft and associates (8). this abnormality remains to be achieved. Muscle Mitochondrial function in the failing heart has cell function is basically a process by which chemi- previously been studied only in experimental ani- cal energy is transformed into the mechanical work mals, where the findings have been conflicting. of myofibrillar shortening and force development. Oxidative phosphorylation and the content of high The presence of a biochemical abnormality in the energy phosphate compounds have been reported failing cardiac muscle must therefore be sought to be normal in some of these studies (9-12), either in the mechanism of energy production or whereas in others defective energy production has in the mechanism of energy utilization by the con- been observed (13-17). Thus, it seemed evident tractile system. The present report is a study of that this problem, in the clinical syndrome of con- energy production in the failing human heart. gestive heart failure, could be solved definitively Considerable evidence has accumulated to indi- only by studying mitochondrial function and mor- cate that myocardial extraction of oxygen and of phology and the content of high energy phosphate oxidizable substrates is not diminished in patients compounds in human myocardial tissue. Accord- with congestive heart failure (1-3). These stud- ingly, the present study was carried out with myo- ies have not, however, provided evidence that the cardial tissue removed at the time of cardiac op- final supply of chemical energy to the contractile erations from 25 patients with congestive heart apparatus is normal. ATP, the immediate source failure. Mitochondria isolated from these tissues of chemical energy utilized by muscle (4), is were shown to possess a high degree of structural formed within the mitochondrion during the oxi- and functional integrity, and the myocardial con- dation of substrates by the process of oxidative tent of high energy phosphate compounds was not phosphorylation. The completeness with which found to be reduced. We concluded, therefore, the process of phosphorylation is coupled to that that there is no evidence for a biochemical abnor- of oxidation determines whether or not the energy mality of energy production in the failing human liberated in the oxidation of substrates becomes heart. available for useful mechanical work by the con- Methods tractile apparatus. A number of toxic agents have been shown to be capable of uncoupling electron This type of investigation on viable human cardiac tissue is now possible because of the development and ap- transport and phosphorylation, both in vitro (5) plication of effective surgical methods for prosthetic re- * Submitted for publication June 21, 1965; accepted placement of cardiac valves. Papillary muscles were re- September 23, 1965. moved from 14 patients with heart failure; in 13 patients, A partial report of this work was presented at a sec- muscles were obtained from the left ventricle at the time tional meeting of the American Society for Clinical In- of removal of diseased mitral valves, and in one patient vestigation, May 2, 1965. muscles were obtained from the right ventricle during t Address requests for reprints to Dr. Charles A. Chid- excision of the tricuspid valve. In all patients rheumatic sey, Dept. of Medicine, University of Colorado School of heart disease was responsible for the valvular deformity, Medicine, 4200 E. Ninth Ave., Denver, Colo. and all were on maintenance digoxin. The patients, seven 40 BIOENERGETICS IN HEART FAILURE 41 men and seven women, were 21 to 57 years of age. The contained the following in a final volume of 1.0 ml: major hemodynamic abnormality in ten patients was glycylglycine buffer (pH 7.4), 40 Amoles; potassium mitral regurgitation; in one patient, mitral stenosis; in phosphate (pH 7.4), 30 umoles; DPN, 1 /mole; cyto- one patient, tricuspid regurgitation; and in two patients, chrome c, 0.015 /mole; MgCl2, 5 /Lmoles; glucose, 25 combined aortic and mitral disease, necessitating replace- timoles; hexokinase (Sigma type III), 0.25 mg; and ment of both the aortic and mitral valves. Hemodynamic mitochondria, 0.25 ml. Incubation was for 20 minutes at evaluation by right and left heart catheterization was car- 30° C. Oxidative rates were determined manometrically, ried out in all 14 patients who comprised this study. To and the net uptake of phosphate was calculated from the represent nonfailing hearts, mitochondria also were pre- differences between initial and final phosphate concentra- pared from right ventricular outflow tract muscle re- tions (22). All incubations were done in duplicate and moved from two male patients with tetralogy of Fallot the average values reported. Determinations of oxygen during correction of this congenital defect. consumption were also carried out with the Clark elec- The general methods utilized in this clinic for mitral trode (23). Mitochondria (0.2 ml) were incubated at valve replacement have been previously described in de- 240 C in a sealed cuvette containing 1.5 ml of the follow- tail (18). The preoperative medications were pento- ing: glycylglycine buffer (pH 7.4), 30 Amoles; potas- barbital, atropine, and meperidine. Anesthesia was in- sium phosphate (pH 7.4), 5 Mmoles; KCl, 180 Amoles; duced with thiopental and maintained with halothane in MgCl2, 12 /moles; and substrate, 10 Amoles. Additions a concentration of 0.5 to 1.0%. The mitral valve was to this medium are indicated in the Figures. Respira- exposed during total cardiopulmonary bypass, and after tory control ratios were determined manometrically and the valve leaflets had been detached from the anulus, the polarographically by dividing the oxidative rates in the papillary muscles were divided from the ventricular wall presence of ADP acceptor by the rate measure when the at their origins and the valve and muscles removed en ADP acceptor was absent (24). ATPase activity was bloc. The patients' temperatures were usually 340 to assayed (21) in a medium containing 40 Emoles glycyl- 350 C, and bypass had been in progress for approximately glycine buffer (pH 7.4), 6 /4moles ATP, 0.2 ml of mito- 10 to 15 minutes when the papillary muscles were tran- chondria, and sufficient 0.25 M sucrose to make a final sected. Immediately upon removal of the specimen, it was volume of 1 ml; additions are as indicated in Table III. placed on ice, dissected, and muscle tissue obtained that Incubations were carried out at 30° C for 10 minutes. was free of fibrous connections to the valve. Measurement of high energy phosphate compounds was Muscle specimens weighing 0.9 to 4.0 g were used for made in biopsies of the myocardium taken from 14 pa- the isolation of mitochondria by a modification of the tients with heart failure in whom replacement of the method of Hatefi, Jurtshuk, and Haavik (19). All tis- mitral or aortic valve or both was performed. In all sues and materials were maintained at 00 C. Tissue patients rheumatic heart disease was responsible for the specimens were pressed through a stainless steel disc valvular deformity, and all were on maintenance digoxin. with 0.5-mm perforations, and this tissue mince was sus- The patients were 21 to 53 years of age; nine were males pended in 4 to 6 vol of 0.25 M sucrose containing ATP, and five females. The major hemodynamic abnormality MgCl2, succinate, and Tris-HCl (pH 7.8) each in a con- in six patients was mitral regurgitation; in one patient, centration of 10' mole per L. Nagarse proteinase 1 was aortic regurgitation; in one patient, mitral stenosis; in added to a concentration of 1 mg per ml and the mixture six patients, aortic stenosis; and in one patient aortic incubated in an ice bath for 20 minutes and intermittently stenosis was combined with mitral valve disease, neces- stirred with a magnetic stirring bar. The tissue mince sitating replacement of both valves. For comparison, was transferred to a smooth-walled homogenizing vessel biopsies also were taken at the time of cardiac operation and disrupted with a loose-fitting motor-driven Teflon from eight patients without previous histories of heart pestle with 15 strokes. The homogenate was centrifuged failure who were undergoing repair of septal defects or in a refrigerated centrifuge at 1,000 X g (mean force) pultnonic stenosis. Biopsies were taken from the right for 10 minutes. The supernatant fluid was decanted and ventricle in the nonfailure group and from the left ven- centrifuged again at 25,000 X g for 10 minutes to obtain tricle in the failure group 2 to 10 minutes after the in- the mitochondrial pellet. This was washed with 0.25 M stitution of total cardiopulmonary bypass. In all pa- sucrose, recentrifuged at 25,000 X g for 10 minutes, and tients body temperatures were 340 to 350 C, and the resuspended in sufficient 0.25 M sucrose to make a sus- coronary circulation was intact.