Role of ketone bodies in perinatal myocardial energy metabolism

2001 ◽  
Vol 29 (2) ◽  
pp. 325-330 ◽  
Author(s):  
B. Bartelds ◽  
F. R. van der Leij ◽  
J. R. G. Kuipers

Metabolic changes at around the time of birth are crucial for life. Here we review the energy utilization in the myocardium, emphasizing ketone body metabolism. Before birth, glucose and lactate are the major energy substrates for the myocardium. Long-chain fatty acids (LCFA) are normally not available as an energy substrate for the fetal heart; however, when LCFA are supplied artificially in near-term fetal lambs, they are readily oxidized. Hence the myocardium has no limitation to its ability to use LCFA before birth. After birth, lactate remains an important energy source for the myocardium, whereas the contribution of glucose to myocardial energy production decreases despite an increase in the supply of glucose. The oxidation of ketone bodies increases after birth in relation to an increase in supply. However, ketone bodies account for only 7% of left ventricular oxygen consumption. The supply and contribution of LCFA to the myocardium increases after birth; the oxidation of LCFA accounts for most of the left ventricular oxygen consumption. Hence the role of ketone bodies in myocardial metabolism is limited. However, there are interesting observations on interference between the uptake of different substrates and the release of ketone bodies, which might have consequences for our interpretation of ketone body utilization.

2016 ◽  
Vol 310 (2) ◽  
pp. E103-E115 ◽  
Author(s):  
Lionel Carneiro ◽  
Sarah Geller ◽  
Xavier Fioramonti ◽  
Audrey Hébert ◽  
Cendrine Repond ◽  
...  

Monocarboxylates have been implicated in the control of energy homeostasis. Among them, the putative role of ketone bodies produced notably during high-fat diet (HFD) has not been thoroughly explored. In this study, we aimed to determine the impact of a specific rise in cerebral ketone bodies on food intake and energy homeostasis regulation. A carotid infusion of ketone bodies was performed on mice to stimulate sensitive brain areas for 6 or 12 h. At each time point, food intake and different markers of energy homeostasis were analyzed to reveal the consequences of cerebral increase in ketone body level detection. First, an increase in food intake appeared over a 12-h period of brain ketone body perfusion. This stimulated food intake was associated with an increased expression of the hypothalamic neuropeptides NPY and AgRP as well as phosphorylated AMPK and is due to ketone bodies sensed by the brain, as blood ketone body levels did not change at that time. In parallel, gluconeogenesis and insulin sensitivity were transiently altered. Indeed, a dysregulation of glucose production and insulin secretion was observed after 6 h of ketone body perfusion, which reversed to normal at 12 h of perfusion. Altogether, these results suggest that an increase in brain ketone body concentration leads to hyperphagia and a transient perturbation of peripheral metabolic homeostasis.


1987 ◽  
Vol 40 (2) ◽  
pp. 221 ◽  
Author(s):  
DW Pethick ◽  
N Harman ◽  
JK Chong

The role of circulating, non-esterified, long-chain fatty acids (NEFA) as a source of energy for the whole animal and skeletal muscle was investigated in fed non-pregnant sheep at rest and during exercise. Infusion of tracer quantities of [1-14C]oleic or [l-14C]stearic acid was combined with the use of arteriovenous difference studies on fed sheep at rest or during a 2 h period of exercise on a belt treadmill moving at 4� 5 km h -I. At rest all parameters of NEFA metabolism indicated a minimal role for oxidation. Thus the concentration in plasma (0'07 � 0�01 mmol I-I), entry rate (0'08 � 0�02 mmol h- I kg-I body wt), contribution to whole animal oxidation (1'2 � 0'3%) and utilization of NEFA by skeletal muscle (0'046 � 0�008 mmol h- I kg-I muscle) were all low. Exercise prompted a shift to lipolysis and accordingly the above parameters increased markedly some 13-24-fold. The circulating concentration of ketone bodies showed only a small increase during exercise and consequently the role of ketone bodies as an energy source during exercise was minimal. Glucose utilization by skeletal muscle was considerable in animals at rest and it represented the most significant potential fuel of skeletal muscle. Exercise resulted in a sustained increase of 3-4-fold in the utilization of glucose by skeletal muscle. Thus the traditional view that NEF A and not glucose is a predominant fuel of skeletal muscle of fed sheep should be appraised.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
E Zweck ◽  
V Burkart ◽  
C Wessel ◽  
D Scheiber ◽  
K H M Leung ◽  
...  

Abstract Background Impairment of myocardial mitochondrial function is regarded as an established pathomechanism in heart failure. Enhanced oxidation of ketone bodies may potentially exert protective effects on myocardial function. High-resolution respirometry (HRR) resembles a gold-standard methodology to determine myocardial mitochondrial metabolism and oxidative function but has not been validated for ketone substrates yet. Purpose We hypothesized that (1) quantification of ketone body oxidative capacity (OC) in myocardium utilizing ex-vivo HRR is feasible and that (2) ketone-associated OC is elevated after fasting and under conditions of chronic mechanical ventricular unloading. Methods We established new HRR (Oxygraph-2k) protocols, measuring oxygen flux generated by oxidation of the ketone substrates beta-hydroxybutyrate (HBA) and acetoacetate (ACA). Ketone protocols were then applied to twelve C57BL/6 mice' (of which six were fasted for 16h) left ventricular and right liver lobe tissue, as well as to eleven terminal heart failure patients' left ventricular tissue, harvested at heart transplantation. Heart transplant recipients were subdivided into patients with left ventricular assist device prior to transplantation (LVAD group, n=6) or no unloading prior to transplantation (HTX group, n=5). Results In non-fasted rodent hearts, HBA yielded an OC of 25±4 pmol/(s*mg tissue) above basal respiration, when applied as sole substrate (21±11 pmol/(s*mg) in liver). ACA alone did not induce oxygen flux, but ACA+succinate yielded 229% higher oxygen flux than succinate alone in state III (146±32 vs 44±12 pmol/(s*mg); p=0.0003). When titrated after succinate, ACA increased OC by 93±25 pmol/(s*mg) (p=0.0003). In 16h-fasted rodent hearts, HBA-supported OC was 27% higher (41±3 vs 52±9 pmol/(s*mg); p=0.04), while OC with ACA+succinate was unchanged (p=0.60). In rodent liver, no oxygen flux was induced by ACA, reflecting absence of 3-oxoacid CoA-transferase. However, HBA-supported OC was 118% higher in fasted liver (37±13 vs 57±13 pmol/(s*mg); p=0.03). In humans, left ventricular unloading was not associated with altered myocardial OC for fatty acids and glycolytic substrates (standard protocol, p=0.13), but HBA-supported OC was 39% higher in the LVAD group compared to the HTX group (54±12 vs 39±9 pmol/(s*mg), p=0.04). Conclusion Quantification of ketone body OC with HRR is feasible in permeabilized myocardial fibers. Applying this novel method revealed increased HBA-supported myocardial mitochondrial respiration after fasting and chronic left ventricular unloading. These data support a concept of enhanced ketone oxidation following ventricular unloading in myocardial mitochondria. Our findings facilitate new studies on myocardial ketone turnover and the interaction of mitochondrial ketone metabolism with cardiac performance. Acknowledgement/Funding CRC 1116, Research commission of the University Hospital Düsseldorf


1983 ◽  
Vol 244 (6) ◽  
pp. H799-H806 ◽  
Author(s):  
K. A. Fox ◽  
H. Nomura ◽  
B. E. Sobel ◽  
S. R. Bergmann

Assessments of myocardial metabolism based on external detection of accumulation of radiolabeled substrates may be influenced, as a result of alterations in flow, by altered substrate delivery as well as altered work (with concomitant changes in metabolic requirements). To determine whether reduced delivery limits substrate utilization under defined conditions of reduced perfusion, an isolated rabbit heart preparation was employed in which flow was reduced but myocardial oxygen consumption (MVo2) and work were kept constant by adjustment of left ventricular end-diastolic pressure and heart rate. Flow was reduced from 1.5 to 0.5 ml . g-1 . min-1, while work was maintained constant in hearts functioning at either low or high levels of MVo2. Consumption of palmitate remained constant (48.8 +/- 11.6 and 68.8 +/- 23.3 nmol . g-1 . min-1), because the proportion of palmitate extracted increased (8.8 +/- 4 to 29.1 +/- 7.2% and 10.3 +/- 3.4 to 21.0 +/- 6.1%). The results indicate that, despite reduction of flow, hearts at constant work loads can extract increasing proportions of delivered substrates such that net utilization remains constant until flow is reduced below the level required to maintain cellular function. They suggest that, under conditions of low flow, impaired extraction of substrates reflects either primarily or secondarily depressed myocardial metabolism rather than simply decreased delivery of substrate.


2019 ◽  
Vol 149 (12) ◽  
pp. 2120-2132 ◽  
Author(s):  
Elizabeth R Axton ◽  
Laura M Beaver ◽  
Lindsey St. Mary ◽  
Lisa Truong ◽  
Christiana R Logan ◽  
...  

ABSTRACT Background Dietary nitrate improves exercise performance by reducing the oxygen cost of exercise, although the mechanisms responsible are not fully understood. Objectives We tested the hypothesis that nitrate and nitrite treatment would lower the oxygen cost of exercise by improving mitochondrial function and stimulating changes in the availability of metabolic fuels for energy production. Methods We treated 9-mo-old zebrafish with nitrate (sodium nitrate, 606.9 mg/L), nitrite (sodium nitrite, 19.5 mg/L), or control (no treatment) water for 21 d. We measured oxygen consumption during a 2-h, strenuous exercise test; assessed the respiration of skeletal muscle mitochondria; and performed untargeted metabolomics on treated fish, with and without exercise. Results Nitrate and nitrite treatment increased blood nitrate and nitrite levels. Nitrate treatment significantly lowered the oxygen cost of exercise, as compared with pretreatment values. In contrast, nitrite treatment significantly increased oxygen consumption with exercise. Nitrate and nitrite treatments did not change mitochondrial function measured ex vivo, but significantly increased the abundances of ATP, ADP, lactate, glycolytic intermediates (e.g., fructose 1,6-bisphosphate), tricarboxylic acid (TCA) cycle intermediates (e.g., succinate), and ketone bodies (e.g., β-hydroxybutyrate) by 1.8- to 3.8-fold, relative to controls. Exercise significantly depleted glycolytic and TCA intermediates in nitrate- and nitrite-treated fish, as compared with their rested counterparts, while exercise did not change, or increased, these metabolites in control fish. There was a significant net depletion of fatty acids, acyl carnitines, and ketone bodies in exercised, nitrite-treated fish (2- to 4-fold), while exercise increased net fatty acids and acyl carnitines in nitrate-treated fish (1.5- to 12-fold), relative to their treated and rested counterparts. Conclusions Nitrate and nitrite treatment increased the availability of metabolic fuels (ATP, glycolytic and TCA intermediates, lactate, and ketone bodies) in rested zebrafish. Nitrate treatment may improve exercise performance, in part, by stimulating the preferential use of fuels that require less oxygen for energy production.


1978 ◽  
Vol 172 (3) ◽  
pp. 377-387 ◽  
Author(s):  
A P Halestrap

The effects of exchangeable ions and pH on the efflux of pyruvate from preloaded mitochondria are reported. Efflux obeys first-order kinetics, and the stimulation of efflux by exchangeable ions such as acetoacetate and lactate obeys Michaelis–Menten kinetics. The apparent Km value +/- S.E. for acetoacetate was 0.56 +/- 0.14 mM (n = 5) and that for lactate 12.3 +/- 2.3 mM (n = 6). The Vmax. values +/- S.E. at 0 degrees C were 16.2 +/- 2.0 and 21.9 +/- 2.7 nmol/min per mg of protein. The exchange of a variety of other substituted monocarboxylates was also studied. Efflux was also stimulated by increasing the external pH. The data gave a pK for the transport process of 8.35 and a Vmax. of 3.31 +/- 0.14 nmol/min per mg. The similarity of the Vmax. values for various exchangeable ions but the difference of this from the Vmax. in the absence of exchangeable ions may indicate that transport of pyruvate occurs with H+ and not in exchange for an OH- ion. The inhibition of transport by alpha-cyano-4-hydroxycinnamate took several seconds to reach completion at 0 degrees C. It is proposed that inhibition occurs by binding to the substrate site and subsequent reaction with an -SH group on the inside of the membrane. The inhibitor can be displaced by substrates that can also enter the mitochondria independently of the carrier and so compete with the inhibitor for the substrate-binding site on the inside of the membrane. A mechanism for transport is proposed that invokes a transition state of pyruvate involving addition of an -SH group to the 2-carbon of pyruvate. Evidence is presented that suggests that ketone bodies may cross the mitochondrial membrane either on the carrier or by free diffusion. The physiological involvement of the carrier in ketone-body metabolism is discussed. The role of ketone bodies and pH in the physiological regulation of pyruvate transport is considered.


2000 ◽  
Vol 279 (6) ◽  
pp. H2855-H2864 ◽  
Author(s):  
Akio Saeki ◽  
Yoichi Goto ◽  
Katsuya Hata ◽  
Toshiyuki Takasago ◽  
Takehiko Nishioka ◽  
...  

Heart temperature affects left ventricular (LV) function and myocardial metabolism. However, how and whether increasing heart temperature affects LV mechanoenergetics remain unclear. We designed the present study to investigate effects of increased temperature by 5°C from 36°C on LV contractility and energetics. We analyzed the LV contractility index ( Emax) and the relation between the myocardial oxygen consumption (MV˙o2) and the pressure-volume area (PVA; a measure of LV total mechanical energy) in isovolumically contracting isolated canine hearts during normothermia (NT) and hyperthermia (HT). HT reduced Emaxby 38% ( P < 0.01) and shortened time to Emaxby 20% ( P < 0.05). HT, however, altered neither the slope nor the unloaded MV˙o2of the MV˙o2-PVA relation. HT increased the oxygen cost of contractility (the incremental ratio of unloaded MV˙o2to Emax) by 49%. When Ca2+infusion restored the reduced LV contractility during HT to the NT baseline level, the unloaded MV˙o2in HT exceeded the NT value by 36%. We conclude that HT-induced negative inotropism accompanies an increase in the oxygen cost of contractility.


1992 ◽  
Vol 263 (6) ◽  
pp. H1724-H1731 ◽  
Author(s):  
E. O. McFalls ◽  
D. J. Duncker ◽  
R. Krams ◽  
L. M. Sassen ◽  
A. Hoogendoorn ◽  
...  

We characterized postischemic changes in myocardial metabolism and regional external work, as measured by the integral of left ventricular pressure-segment-length loops. In 12 anesthetized swine, the left anterior descending coronary artery (LAD) was occluded for 10 min and reperfused for 30 min for two successive cycles. Before ischemia, regional work was 16,920 +/- 5,630 mmHg-mm/min and after stunning, work was reduced to 50 +/- 14% (P < 0.05). At baseline, oxygen and lactate consumption were 4.80 +/- 1.40 and 1.02 +/- 0.46 mumol.min-1 x g-1, respectively, and after stunning they were reduced to 3.24 +/- 0.80 (P < 0.05) and 0.16 +/- 0.21 mumol.min-1 x g-1 (P < 0.05), respectively. The atria were then paced 50 beats/min higher than the reperfusion heart rate, during and without an infusion of dobutamine (2 micrograms.kg-1 x min-1). During dobutamine, both regional external work and oxygen consumption returned to 98% of preischemic values, but lactate utilization remained depressed. We conclude that regional external work and oxygen consumption remain coupled during inotropic stimulation after stunning, with a preferential shift toward nonlactate substrates.


1965 ◽  
Vol 208 (1) ◽  
pp. 162-168 ◽  
Author(s):  
E. Bassenge ◽  
V. E. Wendt ◽  
P. Schollmeyer ◽  
G. Blümchen ◽  
S. Gudbjarnason ◽  
...  

The effect of acetoacetate infusion on myocardial metabolism was studied in 13 dogs at varying concentrations of acetoacetate. Acetoacetate was extracted by the myocardium at arterial levels of from 1 to 54 mg/100 ml. At arterial levels of above 60 mg/100 ml, extraction of acetoacetate by the heart was very small. Considerable amounts of the infused acetoacetate were reduced to beta-hydroxybutyrate. Acetoacetate inhibited the utilization of free fatty acids by the heart, resulting in a rise in the respiratory quotient of the heart. An increase in the myocardial extraction of lactate occurred at arterial acetoacetate levels of below 34 mg/100 ml. Between 34 and 80 mg/100 ml of acetoacetate levels, myocardial lactate extraction declined; the ketone became the preferred fuel of the myocardium at arterial acetoacetate levels between 34 and 54 mg/100 ml. Arterial glucose levels fell gradually during the experiment, leading to severe hypoglycemia. The negative myocardial balance of pyruvate significantly increased throughout the experiment. Coronary blood flow, heart rate, left ventricular pressure, myocardial contractility, and EKG were not affected significantly by arterial acetoacetate levels ranging from 1 to 80 mg/100 ml.


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