scholarly journals Mechanisms underlying neonate specific metabolic effects of volatile anesthetics

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Julia Stokes ◽  
Arielle Freed ◽  
Rebecca Bornstein ◽  
Kevin N Su ◽  
John Snell ◽  
...  
Keyword(s):  
Volatile Anesthetics ◽  
Metabolic Effects ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Transport Chain ◽  
Malonyl Coa ◽  
Citrate Accumulation ◽  
Neonatal Brain Development ◽  
Neonatal Blood ◽  
The Impact

Volatile anesthetics (VAs) are widely used in medicine, but the mechanisms underlying their effects remain ill-defined. Though routine anesthesia is safe in healthy individuals, instances of sensitivity are well-documented, and there has been significant concern regarding the impact of VAs on neonatal brain development. Evidence indicates that VAs have multiple targets, with anesthetic and non-anesthetic effects mediated by neuroreceptors, ion channels, and the mitochondrial electron transport chain. Here, we characterize an unexpected metabolic effect of VAs in neonatal mice. Neonatal blood β-hydroxybutarate (β-HB) is rapidly depleted by VAs at concentrations well below those necessary for anesthesia. β-HB in adults, including animals in dietary ketosis, is unaffected. Depletion of β-HB is mediated by citrate accumulation, malonyl-CoA production by acetyl-CoA carboxylase, and inhibition of fatty acid oxidation. Adults show similar significant changes to citrate and malonyl-CoA, but are insensitive to malonyl-CoA, displaying reduced metabolic flexibility compared to younger animals.

scholarly journals Mechanisms underlying neonate specific metabolic effects of volatile anesthetics

2020 ◽  
Author(s):  
Julia Stokes ◽  
Arielle Freed ◽  
Amanda Pan ◽  
Grace X Sun ◽  
Rebecca Bornstein ◽  
...  
Keyword(s):  
Volatile Anesthetics ◽  
Metabolic Effects ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Transport Chain ◽  
Malonyl Coa ◽  
Citrate Accumulation ◽  
Neonatal Brain Development ◽  
Neonatal Blood ◽  
The Impact

Volatile anesthetics (VAs) are widely used in medicine, but the mechanisms underlying their effects remain ill-defined. Though routine anesthesia is safe in healthy individuals, instances of sensitivity are well-documented, and there has been significant concern regarding the impact of VAs on neonatal brain development. Evidence indicates that VAs have multiple targets, with anesthetic and non-anesthetic effects mediated by neuroreceptors, ion channels, and the mitochondrial electron transport chain. Here, we characterize an unexpected metabolic effect of VAs in neonatal mice. Neonatal blood β-hydroxybutarate (ß-HB) is rapidly depleted by VAs at concentrations well below those necessary for anesthesia. β-HB in adults, including animals in dietary ketosis, is unaffected. Depletion of β-HB is mediated by citrate accumulation, malonyl-CoA production by acetyl-CoA carboxylase, and inhibition of fatty acid oxidation. Adults show similar significant changes to citrate and malonyl-CoA, but are insensitive to malonyl-CoA, displaying reduced metabolic flexibility compared to younger animals.

Effect of phosphorylation by AMP-activated protein kinase on palmitoyl-CoA inhibition of skeletal muscle acetyl-CoA carboxylase

2005 ◽  
Vol 98 (4) ◽  
pp. 1221-1227 ◽  
Author(s):  
D. S. Rubink ◽  
W. W. Winder
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Oxidation Rates ◽  
Malonyl Coa ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) has previously been demonstrated to phosphorylate and inactivate skeletal muscle acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of malonyl-CoA, an inhibitor of carnitine palmitoyltransferase 1 and fatty acid oxidation. Contraction-induced activation of AMPK with subsequent phosphorylation/inactivation of ACC has been postulated to be responsible in part for the increase in fatty acid oxidation that occurs in muscle during exercise. These studies were designed to answer the question: Does phosphorylation of ACC by AMPK make palmitoyl-CoA a more effective inhibitor of ACC? Purified rat muscle ACC was subjected to phosphorylation by AMPK. Activity was determined on nonphosphorylated and phosphorylated ACC preparations at acetyl-CoA concentrations ranging from 2 to 500 μM and at palmitoyl-CoA concentrations ranging from 0 to 100 μM. Phosphorylation resulted in a significant decline in the substrate saturation curve at all palmitoyl-CoA concentrations. The inhibitor constant for palmitoyl-CoA inhibition of ACC was reduced from 1.7 ± 0.25 to 0.85 ± 0.13 μM as a consequence of phosphorylation. At 0.5 mM citrate, ACC activity was reduced to 13% of control values in response to the combination of phosphorylation and 10 μM palmitoyl-CoA. Skeletal muscle ACC is more potently inhibited by palmitoyl-CoA after having been phosphorylated by AMPK. This may contribute to low-muscle malonyl-CoA values and increasing fatty acid oxidation rates during long-term exercise when plasma fatty acid concentrations are elevated.

Regulation of fatty acid oxidation of the heart by MCD and ACC during contractile stimulation

1999 ◽  
Vol 277 (4) ◽  
pp. E772-E777 ◽  
Author(s):  
Gary W. Goodwin ◽  
Heinrich Taegtmeyer
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Physiological Conditions ◽  
Heart Work ◽  
Rat Hearts ◽  
Malonyl Coa ◽  
Work Transition ◽  
Endogenous Lipids

We tested the hypothesis that the level of malonyl-CoA, as well as the corresponding rate of total fatty acid oxidation of the heart, is regulated by the opposing actions of acetyl-CoA carboxylase (ACC) and malonyl-CoA decarboxylase (MCD). We used isolated working rat hearts perfused under physiological conditions. MCD in heart homogenates was measured specifically by14CO2production from [3-14C]malonyl-CoA, and ACC was measured specifically based on the portion of total carboxylase that is citrate sensitive. Increased heart work (1 μM epinephrine + 40% increase in afterload) elicited a 40% increase in total β-oxidation of exogenous plus endogenous lipids, accompanied by a 33% decrease in malonyl-CoA. The basal activity and citrate sensitivity of ACC (reflecting its phosphorylation state) and citrate content were unchanged. AMP levels were also unchanged. MCD activity, when measured at a subsaturating concentration of malonyl-CoA (50 μM), was increased by 55%. We conclude that physiological increments in AMP during the work transition are insufficient to promote ACC phosphorylation by AMP-stimulated protein kinase. Rather, increased fatty acid oxidation results from increased malonyl-CoA degradation by MCD.

AICA riboside increases AMP-activated protein kinase, fatty acid oxidation, and glucose uptake in rat muscle

1997 ◽  
Vol 273 (6) ◽  
pp. E1107-E1112 ◽  
Author(s):  
G. F. Merrill ◽  
E. J. Kurth ◽  
D. G. Hardie ◽  
W. W. Winder
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Fatty Acid Oxidation ◽  
Fold Increase ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Malonyl Coa ◽  
Amp Activated Protein Kinase

5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR) has previously been reported to be taken up into cells and phosphorylated to form ZMP, an analog of 5′-AMP. This study was designed to determine whether AICAR can activate AMP-activated protein kinase (AMPK) in skeletal muscle with consequent phosphorylation of acetyl-CoA carboxylase (ACC), decrease in malonyl-CoA, and increase in fatty acid oxidation. Rat hindlimbs were perfused with Krebs-Henseleit bicarbonate containing 4% bovine serum albumin, washed bovine red blood cells, 200 μU/ml insulin, and 10 mM glucose with or without AICAR (0.5–2.0 mM). Perfusion with medium containing AICAR was found to activate AMPK in skeletal muscle, inactivate ACC, and decrease malonyl-CoA. Hindlimbs perfused with 2 mM AICAR for 45 min exhibited a 2.8-fold increase in fatty acid oxidation and a significant increase in glucose uptake. No difference was observed in oxygen uptake in AICAR vs. control hindlimb. These results provide evidence that decreases in muscle content of malonyl-CoA can increase the rate of fatty acid oxidation.

Metabolic response to an acute jump in cardiac workload: effects on malonyl-CoA, mechanical efficiency, and fatty acid oxidation

2008 ◽  
Vol 294 (2) ◽  
pp. H954-H960 ◽  
Author(s):  
Lufang Zhou ◽  
Hazel Huang ◽  
Celvie L. Yuan ◽  
Wendy Keung ◽  
Gary D. Lopaschuk ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Energy Expenditure ◽  
Fatty Acid Oxidation ◽  
Mechanical Efficiency ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Malonyl Coa ◽  
High Workload ◽  
Carnitine Palmitoyltransferase I

Inhibition of myocardial fatty acid oxidation can improve left ventricular (LV) mechanical efficiency by increasing LV power for a given rate of myocardial energy expenditure. This phenomenon has not been assessed at high workloads in nonischemic myocardium; therefore, we subjected in vivo pig hearts to a high workload for 5 min and assessed whether blocking mitochondrial fatty acid oxidation with the carnitine palmitoyltransferase-I inhibitor oxfenicine would improve LV mechanical efficiency. In addition, the cardiac content of malonyl-CoA (an endogenous inhibitor of carnitine palmitoyltransferase-I) and activity of acetyl-CoA carboxylase (which synthesizes malonyl-CoA) were assessed. Increased workload was induced by aortic constriction and dobutamine infusion, and LV efficiency was calculated from the LV pressure-volume loop and LV energy expenditure. In untreated pigs, the increase in LV power resulted in a 2.5-fold increase in fatty acid oxidation and cardiac malonyl-CoA content but did not affect the activation state of acetyl-CoA carboxylase. The activation state of the acetyl-CoA carboxylase inhibitory kinase AMP-activated protein kinase decreased by 40% with increased cardiac workload. Pretreatment with oxfenicine inhibited fatty acid oxidation by 75% and had no effect on cardiac energy expenditure but significantly increased LV power and LV efficiency (37 ± 5% vs. 26 ± 5%, P < 0.05) at high workload. In conclusion, 1) myocardial fatty acid oxidation increases with a short-term increase in cardiac workload, despite an increase in malonyl-CoA concentration, and 2) inhibition of fatty acid oxidation improves LV mechanical efficiency by increasing LV power without affecting cardiac energy expenditure.

Inactivation of acetyl-CoA carboxylase and activation of AMP-activated protein kinase in muscle during exercise

1996 ◽  
Vol 270 (2) ◽  
pp. E299-E304 ◽  
Author(s):  
W. W. Winder ◽  
D. G. Hardie
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Ammonium Sulfate ◽  
Quadriceps Muscle ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Rat Skeletal Muscle ◽  
Malonyl Coa ◽  
Amp Activated Protein Kinase

Malonyl-CoA, an inhibitor of fatty acid oxidation in skeletal muscle mitochondria, decreases in rat skeletal muscle during exercise or in response to electrical stimulation. Regulation of rat skeletal muscle acetyl-CoA carboxylase (ACC), the enzyme that synthesizes malonyl-CoA, was studied in vitro and in vivo. Avidin-Sepharose affinity-purified ACC from hindlimb skeletal muscle was phosphorylated by purified liver AMP-activated protein kinase with a concurrent decrease in ACC activity. AMP-activated protein kinase was quantitated in resuspended ammonium sulfate precipitates of the fast-twitch red (type IIa fibers) region of the quadriceps muscle. Rats running on a treadmill at 21 m/min up a 15% grade show a 2.4-fold activation of AMP-activated protein kinase concurrently with a marked decrease in ACC activity in the resuspended ammonium sulfate precipitates at all citrate concentrations ranging from 0 to 20 mM. Malonyl-CoA decreased from a resting value of 1.85 +/- 0.29 to 0.50 +/- 0.09 nmol/g in red quadriceps muscle after 30 min of treadmill running. The activation of the AMP-activated protein kinase with consequent phosphorylation and inactivation of ACC may be one of the primary events in the control of malonyl-CoA and hence fatty acid oxidation during exercise.

Malonyl CoA control of fatty acid oxidation in the newborn heart in response to increased fatty acid supply

2006 ◽  
Vol 84 (11) ◽  
pp. 1215-1222 ◽  
Author(s):  
Arzu Onay-Besikci ◽  
Nandakumar Sambandam
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Myocardial Fatty Acid ◽  
Acetyl Coa ◽  
Tissue Levels ◽  
Post Surgery ◽  
Malonyl Coa

The concentration of fatty acids in the blood or perfusate is a major determinant of the extent of myocardial fatty acid oxidation. Increasing fatty acid supply in adult rat increases myocardial fatty acid oxidation. Plasma levels of fatty acids increase post-surgery in infants undergoing cardiac bypass operation to correct congenital heart defects. How a newborn heart responds to increased fatty acid supply remains to be determined. In this study, we examined whether the tissue levels of malonyl CoA decrease to relieve the inhibition on carnitine palmitoyltransferase (CPT) I when the myocardium is exposed to higher concentrations of long-chain fatty acids in newborn rabbit heart. We then tested the contribution of the enzymes that regulate tissue levels of malonyl CoA, acetyl CoA carboxylase (ACC), and malonyl CoA decarboxylase (MCD). Our results showed that increasing fatty acid supply from 0.4 mmol/L (physiological) to 1.2 mmol/L (pathological) resulted in an increase in cardiac fatty acid oxidation rates and this was accompanied by a decrease in tissue malonyl CoA levels. The decrease in malonyl CoA was not related to any alterations in total and phosphorylated acetyl CoA carboxylase protein or the activities of acetyl CoA carboxylase and malonyl CoA decarboxylase. Our results suggest that the regulatory role of malonyl CoA remained when the hearts were exposed to high levels of fatty acids.

Abstract 107: Acetyl-coa Carboxylase 2 Prevents Cardiomyocyte Hypertrophy by Reducing Glucose Reliance

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Julia Ritterhoff ◽  
Dan Shao ◽  
Rong Tian
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cardiac Hypertrophy ◽  
Cardiomyocyte Hypertrophy ◽  
Acid Oxidation ◽  
Acid Uptake ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
The Impact

In cardiac hypertrophy, the adult heart switches from mainly using fatty acids to increased reliance on glucose to maintain its energetic demands. Reducing fatty acid overload and further increasing glucose reliance has been suggested to be beneficial in the diseased state. Recently, however, it has been shown that increasing fatty acid oxidation (FAO) by cardiac-specific deletion of Acetyl-CoA Carboxylase 2 (ACC2) maintains cardiac energetics and prevents cardiac dysfunction as well as cardiomyocyte hypertrophy during chronic pressure overload. However, it remained unclear, how increased FAO specifically prevented cardiomyocyte hypertrophy. Thus, the goal of this study was to determine the impact of ACC2 deletion on cardiomyocyte hypertrophy in vitro . Adenoviral-mediated knock-down (KD) of ACC2 in adult rat ventricular cardiomyocytes (CMs) resulted in a 70% downregulation of ACC2 mRNA. In standard CM medium (medium M199, 5.5mM glucose) ACC2 KD resulted in a similar increase in CM growth after phenylephrine (PE) treatment as control CMs (+39±10% in control vs. 41±16% in ACC2 KD CMs). Supplementation of 0.4 mM mixed long-chain fatty acids (FA) and 0.1 mU/ml insulin had no effect on cardiomyocyte morphology or hypertrophic response after PE treatment (+42±6%). However, ACC2 KD effectively prevented CM hypertrophy after PE stimulation in the presence of FA/insulin (+9±6%). Whereas PE stimulation in control CMs increased glucose uptake (+28±8%) and reduced fatty acid uptake (-25±6%), both were normalized after ACC2 KD. Inhibiting FAO by etomoxir or increasing glucose utilization by dichloroacetate abolished the beneficial effects of ACC2 KD after PE stimulation. When cultured in glucose-free medium supplemented with FA, ACC2 KD was incapable of preventing cardiomyocyte hypertrophy. Together, these data indicate that increased FAO after ACC2 deletion prevents cardiomyocyte hypertrophy by reducing glucose reliance, suggesting that rather increasing than reducing FAO is beneficial in cardiac hypertrophy.

scholarly journals Metabolic Effects of Late Dinner in Healthy Volunteers—A Randomized Crossover Clinical Trial

2020 ◽  
Vol 105 (8) ◽  
pp. 2789-2802 ◽  
Author(s):  
Chenjuan Gu ◽  
Nga Brereton ◽  
Amy Schweitzer ◽  
Matthew Cotter ◽  
Daisy Duan ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Healthy Volunteers ◽  
Fatty Acid Oxidation ◽  
Dietary Fatty Acid ◽  
Metabolic Effects ◽  
Acid Oxidation ◽  
Sleep Phase ◽  
Female Age ◽  
Postprandial Period ◽  
The Impact

Abstract Context Consuming calories later in the day is associated with obesity and metabolic syndrome. We hypothesized that eating a late dinner alters substrate metabolism during sleep in a manner that promotes obesity. Objective The objective of this work is to examine the impact of late dinner on nocturnal metabolism in healthy volunteers. Design and Setting This is a randomized crossover trial of late dinner (LD, 22:00) vs routine dinner (RD, 18:00), with a fixed sleep period (23:00-07:00) in a laboratory setting. Participants Participants comprised 20 healthy volunteers (10 male, 10 female), age 26.0 ± 0.6 years, body mass index 23.2 ± 0.7 kg/m2, accustomed to a bedtime between 22:00 and 01:00. Interventions An isocaloric macronutrient diet was administered on both visits. Dinner (35% daily kcal, 50% carbohydrate, 35% fat) with an oral lipid tracer ([2H31] palmitate, 15 mg/kg) was given at 18:00 with RD and 22:00 with LD. Main Outcome Measures Measurements included nocturnal and next-morning hourly plasma glucose, insulin, triglycerides, free fatty acids (FFAs), cortisol, dietary fatty acid oxidation, and overnight polysomnography. Results LD caused a 4-hour shift in the postprandial period, overlapping with the sleep phase. Independent of this shift, the postprandial period following LD was characterized by higher glucose, a triglyceride peak delay, and lower FFA and dietary fatty acid oxidation. LD did not affect sleep architecture, but increased plasma cortisol. These metabolic changes were most pronounced in habitual earlier sleepers determined by actigraphy monitoring. Conclusion LD induces nocturnal glucose intolerance, and reduces fatty acid oxidation and mobilization, particularly in earlier sleepers. These effects might promote obesity if they recur chronically.

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