scholarly journals Effects of 3-hydroxybutyrate and free fatty acids on muscle protein kinetics and signaling during LPS-induced inflammation in humans: anticatabolic impact of ketone bodies

2018 ◽  
Vol 108 (4) ◽  
pp. 857-867 ◽  
Author(s):  
Henrik H Thomsen ◽  
Nikolaj Rittig ◽  
Mogens Johannsen ◽  
Andreas B Møller ◽  
Jens Otto Jørgensen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Acute Inflammation ◽  
Ketone Bodies ◽  
Muscle Protein ◽  
Initiation Factor ◽  
Whole Body ◽  
Protein Breakdown ◽  
Protein Kinetics ◽  
Nonesterified Fatty Acids

Abstract Background Acute inflammation, and subsequent release of bacterial products (e.g. LPS), inflammatory cytokines, and stress hormones, is catabolic, and the loss of lean body mass predicts morbidity and mortality. Lipid intermediates may reduce protein loss, but the roles of free fatty acids (FFAs) and ketone bodies during acute inflammation are unclear. Objective We aimed to test whether infusions of 3-hydroxybutyrate (3OHB), FFAs, and saline reduce protein catabolism during exposure to LPS and Acipimox (to restrict and control endogenous lipolysis). Design A total of 10 healthy male subjects were randomly tested 3 times, with: 1) LPS, Acipimox (Olbetam) and saline, 2) LPS, Acipimox, and nonesterified fatty acids (Intralipid), and 3) LPS, Acipimox, and 3OHB, during a 5-h basal period and a 2-h hyperinsulinemic, euglycemic clamp. Labeled phenylalanine, tyrosine, and urea tracers were used to estimate protein kinetics, and muscle biopsies were taken for Western blot analysis of protein metabolic signaling. Results 3OHB infusion increased 3OHB concentrations (P < 0.0005) to 3.5 mM and decreased whole-body phenylalanine-to-tyrosine degradation. Basal and insulin-stimulated net forearm phenylalanine release decreased by >70% (P < 0.005), with both appearance and phenylalanine disappearance being profoundly decreased. Phosphorylation of eukaryotic initiation factor 2α at Ser51 was increased in skeletal muscle, and S6 kinase phosphorylation at Ser235/236 tended (P = 0.074) to be decreased with 3OHB infusion (suggesting inhibition of protein synthesis), whereas no detectable effects were seen on markers of protein breakdown. Lipid infusion did not affect phenylalanine kinetics, and insulin sensitivity was unaffected by interventions. Conclusion During acute inflammation, 3OHB has potent anticatabolic actions in muscle and at the whole-body level; in muscle, reduction of protein breakdown overrides inhibition of synthesis. This trial was registered at clinicaltrials.gov as NCT01752348.

Variation of plasma ketones and free fatty acids during acute cold exposure in man

1965 ◽  
Vol 20 (1) ◽  
pp. 56-60 ◽  
Author(s):  
Peter G. Hanson ◽  
Robert E. Johnson
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Cold Exposure ◽  
Ketone Bodies ◽  
Control Period ◽  
Exposure Period ◽  
Nonesterified Fatty Acids ◽  
Acute Cold Exposure ◽  
Plasma Ffa ◽  
And Control

We have studied the magnitude of ketosis induced during acute cold exposure. Plasma and urinary ketone bodies and plasma free fatty acids (FFA) were followed in four healthy young men at rest during a 90-min period of seminude exposure to 0 C in still air. This period was followed by 4 hr of recovery at 25 C. Each subject served as his own control throughout an experimental sequence in which one cold-exposure and corresponding control period (25 C) were experienced each week for 3 successive weeks. The subjects were in a fasting state but with water ad libitum beginning 12 hr prior to the experiment. Light weight clothing was worn during recovery and control periods. The combined group data show a significant increase in plasma FFA during cold exposure as compared with similar control periods. Although true hyperketonemia or hyperketonuria did not develop, the levels of plasma ketones are elevated in the cold-exposure period of the first week. During the second and third week there is no difference between the cold and control plasma ketone concentration. The data suggest that FFA is mobilized as a metabolic substrate during cold exposure and that efficient peripheral utilization of the elevated plasma FFA concentration minimizes hyperketogenesis. ketone bodies; metabolism; nonesterified fatty acids Submitted on April 27, 1964

Elevated plasma free fatty acids decrease basal protein synthesis, but not the anabolic effect of leucine, in skeletal muscle

2006 ◽  
Vol 291 (3) ◽  
pp. E666-E674 ◽  
Author(s):  
Charles H. Lang
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Protein Synthesis ◽  
Free Fatty Acids ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Short Term ◽  
Lipid Infusion ◽  
Igf I ◽  
Plasma Ffas

Elevations in free fatty acids (FFAs) impair glucose uptake in skeletal muscle. However, there is no information pertaining to the effect of elevated circulating lipids on either basal protein synthesis or the anabolic effects of leucine and insulin-like growth factor I (IGF-I). In chronically catheterized conscious rats, the short-term elevation of plasma FFAs by the 5-h infusion of heparin plus Intralipid decreased muscle protein synthesis by ∼25% under basal conditions. Lipid infusion was associated with a redistribution of eukaryotic initiation factor (eIF)4E from the active eIF4E·eIF4G complex to the inactive eIF4E·4E-BP1 complex. This shift was associated with a decreased phosphorylation of eIF4G but not 4E-BP1. Lipid infusion did not significantly alter either the total amount or phosphorylation state of mTOR, TSC2, S6K1, or the ribosomal protein S6 under basal conditions. In control rats, oral leucine increased muscle protein synthesis. This anabolic response was not impaired by lipid infusion, and no defects in signal transduction pathways regulating translation initiation were detected. In separate rats that received a bolus injection of IGF-I, lipid infusion attenuated the normal redistribution of eIF4E from the active to inactive complex and largely prevented the increased phosphorylation of 4E-BP1, eIF4G, S6K1, and S6. This IGF-I resistance was associated with enhanced Ser307 phosphorylation of insulin receptor substrate-1 (IRS-1). These data indicate that the short-term elevation of plasma FFAs impairs basal protein synthesis in muscle by altering eIF4E availability, and this defect may be related to impaired phosphorylation of eIF4G, not 4E-BP1. Moreover, hyperlipidemia impairs IGF-I action but does not produce leucine resistance in skeletal muscle.

scholarly journals Growth Hormone, Alone and in Combination With Insulin, Increases Whole Body and Skeletal Muscle Protein Kinetics in Cancer Patients After Surgery

1999 ◽  
Vol 229 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Russell S. Berman ◽  
Lawrence E. Harrison ◽  
David B. Pearlstone ◽  
Michael Burt ◽  
Murray F. Brennan
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Cancer Patients ◽  
Muscle Protein ◽  
Whole Body ◽  
Skeletal Muscle Protein ◽  
Protein Kinetics

Do nonesterified fatty acids regulate skeletal muscle protein turnover in humans?

1993 ◽  
Vol 265 (3) ◽  
pp. E357-E361 ◽  
Author(s):  
M. Walker ◽  
E. Shmueli ◽  
S. E. Daley ◽  
B. G. Cooper ◽  
K. G. Alberti
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Serum Insulin ◽  
Whole Body ◽  
Nonesterified Fatty Acid ◽  
Elevated Plasma ◽  
Skeletal Muscle Protein ◽  
Plasma Nefa ◽  
Nonesterified Fatty Acids

We examined whether elevated plasma nonesterified fatty acid (NEFA) levels exert a direct effect on protein metabolism by measuring [2H5]phenylalanine skeletal muscle exchange and whole body turnover. [2H5]phenylalanine was infused (0.5 mg.kg-1 x h-1) for 300 min in seven healthy subjects on two occasions. Intralipid (10%; 30 ml/h) or 0.154 mol/l NaCl was infused in random order from 120 min. Measurements were taken during basal (90-120 min) and infusion (270-300 min) periods. Intralipid infusion increased plasma NEFA levels [1.31 +/- 0.13 vs. 0.49 +/- 0.05 (SE) mmol/l; P < 0.05] and forearm NEFA uptake [45 +/- 76 vs. -51 +/- 44 nmol . 100 ml forearm-1 x min-1; P < 0.05]. Serum insulin and blood ketone body levels were similar with the two treatments. Elevated plasma NEFA levels were associated with a comparable decrease in forearm phenylalanine uptake (11 +/- 2 vs. 17 +/- 2 nmol x 100 ml forearm-1 x min-1; lipid vs. control, P < 0.05) and release (20 +/- 2 vs. 26 +/- 3 nmol x 100 ml forearm-1 x min-1; lipid vs. control, P < 0.05). However, there were no significant changes in net forearm phenylalanine exchange and whole body phenylalanine turnover. Therefore, elevated plasma NEFA levels were associated with a comparable decrease in the rates of skeletal muscle protein synthesis and breakdown but did not appear to influence overall protein balance, as assessed using [2H5]phenylalanine.

scholarly journals A Clinical Case of Clozapine-Induced Fatal Diabetic Ketoacidosis

2016 ◽  
Vol 7 ◽  
pp. CMPsy.S30532
Author(s):  
Eric Romney ◽  
Vinay J. Nagaraj ◽  
Amie Kafer
Keyword(s):  
Fatty Acids ◽  
Weight Gain ◽  
Free Fatty Acids ◽  
Diabetic Ketoacidosis ◽  
Ketone Bodies ◽  
Pancreatic Beta Cell ◽  
Metabolic Effects ◽  
Psychotic Symptoms ◽  
Life Threatening ◽  
Altered Metabolism

Introduction Clozapine, a second generation medication, has become the atypical antipsychotic drug of choice for refractory or treatment-resistant schizophrenia. In addition to the high risk of agranulocytosis and seizures, clozapine treatment is increasingly associated with significant metabolic effects, such as hyperglycemia, central weight gain and adiposity, hypertriglyceridemia, and elevated low-density lipoprotein cholesterol. A potentially life-threatening complication of altered metabolism is diabetic ketoacidosis (DKA). This report details a case of fatal DKA in a schizophrenic patient undergoing treatment with clozapine. Case Description An African–American male in his 20s with a medical history significant for schizophrenia was presented to the psychiatric inpatient ward with severe paranoid thoughts and aggressive behavior. After trials of risperidone, olanzapine, and haloperidol—all of which failed to adequately control his psychotic symptoms—clozapine titration was initiated and he showed significant improvement. Weight gain was observed throughout hospitalization, but all blood and urine test results showed no metabolic or hematological abnormalities. The patient was discharged for outpatient treatment on clozapine (125 mg morning and 325 mg evening) along with divalproex sodium and metoprolol. Six days post-discharge, the patient died. A medical autopsy later ruled that the death was due to DKA without any evidence of contributory injuries or natural disease. Results and Conclusion Significant increase in body mass index from 28.7 to 33.5 was observed during hospitalization. The blood glucose level, measured after his death, was found to be 500 mg/dL. Altered metabolism due to clozapine can lead to dyslipidemia-mediated-pancreatic-beta-cell damage, decreased insulin secretion as well as insulin resistance. In DKA, low levels of insulin lead to an increased release of free fatty acids from adipose tissue. Acetyl coenzyme A (CoA), derived from the breakdown of free fatty acids, is metabolized by the Kreb's cycle. In hepatocytes, excess acetyl-CoA is converted into ketone bodies (acetoacetate and β-hydroxybutyrate) and released into circulation. Ketone bodies have a low p Ka value and their high serum concentrations lead to DKA. In this patient, DKA was most probably clozapine induced and had fatal consequences. Thus, recognizing potential risk factors, providing patient education, and increasing monitoring of patients on clozapine and other atypical antipsychotics are critical to prevent the life-threatening effects of DKA.

scholarly journals Anabolic signaling and protein deposition are enhanced by intermittent compared with continuous feeding in skeletal muscle of neonates

2012 ◽  
Vol 302 (6) ◽  
pp. E674-E686 ◽  
Author(s):  
Samer W. El-Kadi ◽  
Agus Suryawan ◽  
Maria C. Gazzaneo ◽  
Neeraj Srivastava ◽  
Renán A. Orellana ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Muscle Protein ◽  
Mrna Translation ◽  
Initiation Factor ◽  
Whole Body ◽  
Signaling Proteins ◽  
Protein Deposition ◽  
Intermittent Bolus ◽  
Continuous Feeding

Orogastric tube feeding is indicated for neonates with impaired ability to ingest and can be administered by intermittent bolus or continuous schedule. Our aim was to determine whether feeding modalities affect muscle protein deposition and to identify mechanisms involved. Neonatal pigs were overnight fasted (FAS) or fed the same amount of food continuously (CON) or intermittently (INT; 7 × 4 h meals) for 29 h. For 8 h, between hours 20 and 28, pigs were infused with [2H5]phenylalanine and [2H2]tyrosine, and amino acid (AA) net balances were measured across the hindquarters. Insulin, branched-chain AA, phenylalanine, and tyrosine arterial concentrations and whole body phenylalanine and tyrosine fluxes were greater for INT after the meal than for CON or FAS. The activation of signaling proteins leading to initiation of mRNA translation, including eukaryotic initiation factor (eIF)4E·eIF4G complex formation in muscle, was enhanced by INT compared with CON feeding or FAS. Signaling proteins of protein degradation were not affected by feeding modalities except for microtubule-associated protein light chain 3-II, which was highest in the FAS. Across the hindquarters, AA net removal increased for INT but not for CON or FAS, with protein deposition greater for INT. This was because protein synthesis increased following feeding for INT but remained unchanged for CON and FAS, whereas there was no change in protein degradation across any dietary treatment. These results suggest that muscle protein accretion in neonates is enhanced with intermittent bolus to a greater extent than continuous feeding, mainly by increased protein synthesis.

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