Dataset Information

Intermittent Bolus Compared With Continuous Feeding Enhances Insulin and Amino Acid Signaling to Translation Initiation in Skeletal Muscle of Neonatal Pigs.

ABSTRACT:

Background

Nutrition administered as intermittent bolus feeds rather than continuously promotes greater protein synthesis rates in skeletal muscle and enhances lean growth in a neonatal piglet model. The molecular mechanisms responsible remain unclear.

Objectives

We aimed to identify the insulin- and/or amino acid-signaling components involved in the enhanced stimulation of skeletal muscle by intermittent bolus compared to continuous feeding in neonatal pigs born at term.

Methods

Term piglets (2-3 days old) were fed equal amounts of sow milk replacer [12.8 g protein and 155 kcal/(kg body weight · d)] by orogastric tube as intermittent bolus meals every 4 hours (INT) or by continuous infusion (CTS). After 21 days, gastrocnemius muscle samples were collected from CTS, INT-0 (before a meal), and INT-60 (60 minutes after a meal) groups (n = 6/group). Insulin- and amino acid-signaling components relevant to mechanistic target of rapamycin complex (mTORC) 1 activation and protein translation were measured.

Results

Phosphorylation of the insulin receptor, IRS-1, PDK1, mTORC2, pan-Akt, Akt1, Akt2, and TSC2 was 106% to 273% higher in the skeletal muscle of INT-60 piglets than in INT-0 and CTS piglets (P < 0.05), but phosphorylation of PTEN, PP2A, Akt3, ERK1/2, and AMPK did not differ among groups, nor did abundances of PHLPP, SHIP2, and Ubl4A. The association of GATOR2 with Sestrin1/2, but not CASTOR1, was 51% to 52% lower in INT-60 piglets than in INT-0 and CTS piglets (P < 0.05), but the abundances of SLC7A5/LAT1, SLC38A2/SNAT2, SLC38A9, Lamtor1/2, and V-ATPase did not differ. Associations of mTOR with RagA, RagC, and Rheb and phosphorylation of S6K1 and 4EBP1, but not eIF2α and eEF2, were 101% to 176% higher in INT-60 piglets than in INT-0 and CTS piglets (P < 0.05).

Conclusions

The enhanced rates of muscle protein synthesis and growth with intermittent bolus compared to continuous feeding in a neonatal piglet model can be explained by enhanced activation of both the insulin- and amino acid-signaling pathways that regulate translation initiation.

SUBMITTER: Suryawan A

PROVIDER: S-EPMC8417931 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature

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Publications

Intermittent Bolus Compared With Continuous Feeding Enhances Insulin and Amino Acid Signaling to Translation Initiation in Skeletal Muscle of Neonatal Pigs.

Suryawan Agus A El-Kadi Samer W SW Nguyen Hanh V HV Fiorotto Marta L ML Davis Teresa A TA

The Journal of nutrition 20210901 9

<h4>Background</h4>Nutrition administered as intermittent bolus feeds rather than continuously promotes greater protein synthesis rates in skeletal muscle and enhances lean growth in a neonatal piglet model. The molecular mechanisms responsible remain unclear.<h4>Objectives</h4>We aimed to identify the insulin- and/or amino acid-signaling components involved in the enhanced stimulation of skeletal muscle by intermittent bolus compared to continuous feeding in neonatal pigs born at term.<h4>Metho ...[more]

PMID: 34159368

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Project description:BackgroundOrogastric tube feeding is indicated in neonates with an impaired ability to ingest food normally and can be administered with an intermittent bolus or continuous feeding schedule.ObjectivesThe objectives were to 1) compare the long-term effect of continuous with intermittent feeding on growth using the newborn pig as a model, 2) determine whether feeding frequency alters lean tissue and fat mass gain, and 3) identify the signaling mechanisms by which protein deposition is controlled in skeletal muscle in response to feeding frequency.DesignNeonatal pigs were fed the same amount of a balanced formula by orogastric tube either as an intermittent bolus meal every 4 h (INT) or as a continuous infusion (CON). Body composition was assessed at the start and end of the study by dual-energy X-ray absorptiometry, and hormone and substrate profiles, muscle mass, protein synthesis, and indexes of nutrient and insulin signaling were measured after 21 d.ResultsBody weight, lean mass, spine length, and skeletal muscle mass were greater in the INT group than in the CON group. Skeletal muscle fractional protein synthesis rates were greater in the INT group after a meal than in the CON group and were associated with higher circulating branched-chain amino acid and insulin concentrations. Skeletal muscle protein kinase B (PKB) and ribosomal protein S6 kinase phosphorylation and eukaryotic initiation factor (eIF) 4E-eIF4G complex formation were higher, whereas eIF2α phosphorylation was lower in the INT group than in the CON group, indicating enhanced activation of insulin and amino acid signaling to translation initiation.ConclusionsThese results suggest that when neonates are fed the same amounts of nutrients as intermittent meals rather than continuously there is greater lean growth. This response can be ascribed, in part, to the pulsatile pattern of amino acids, insulin, or both induced by INT, which enables the responsiveness of anabolic pathways to feeding to be sustained chronically in skeletal muscle.

Project description:Optimizing enteral nutrition for premature infants may help mitigate extrauterine growth restriction and adverse chronic health outcomes. Previously, we showed in neonatal pigs born at term that lean growth is enhanced by intermittent bolus compared with continuous feeding. The objective was to determine if prematurity impacts how body composition, muscle protein synthesis, and myonuclear accretion respond to feeding modality. Following preterm delivery, pigs were fed equivalent amounts of formula delivered either as intermittent boluses (INT; n = 30) or continuously (CONT; n = 14) for 21 days. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and muscle growth was assessed by morphometry, myonuclear accretion, and satellite cell abundance. Tissue anabolic signaling and fractional protein synthesis rates were determined in INT pigs in postabsorptive (INT-PA) and postprandial (INT-PP) states and in CONT pigs. Body weight gain and composition did not differ between INT and CONT pigs. Longissimus dorsi (LD) protein synthesis was 34% greater in INT-PP than INT-PA pigs (P < 0.05) but was not different between INT-PP and CONT pigs. Phosphorylation of 4EBP1 and S6K1 and eIF4E·eIF4G abundance in LD paralleled changes in LD protein synthesis. Satellite cell abundance, myonuclear accretion, and fiber cross-sectional area in LD did not differ between groups. These results suggest that, unlike pigs born at term, intermittent bolus feeding does not enhance lean growth more than continuous feeding in pigs born preterm. Premature birth attenuates the capacity of skeletal muscle to respond to cyclical surges in insulin and amino acids with intermittent feeding in early postnatal life.NEW & NOTEWORTHY Extrauterine growth restriction often occurs in premature infants but may be mitigated by optimizing enteral feeding strategies. We show that intermittent bolus feeding does not increase skeletal muscle protein synthesis, myonuclear accretion, or lean growth more than continuous feeding in preterm pigs. This attenuated anabolic response of muscle to intermittent bolus feeding, compared with previous observations in pigs born at term, may contribute to deficits in lean mass that many premature infants exhibit into adulthood.

Project description:BackgroundPhototherapy is a widely accepted, effective first-line therapy for neonatal jaundice. It is traditionally used continuously but intermittent phototherapy has been proposed as an equally effective alternative with practical advantages of improved maternal feeding and bonding. The effectiveness of intermittent phototherapy compared with continuous phototherapy is unknown.ObjectivesTo assess the safety and effectiveness of intermittent phototherapy compared with continuous phototherapy.Search methodsSearches were conducted on 31 January 2022 in the following databases: CENTRAL via CRS Web, MEDLINE and Embase via Ovid. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-randomised trials.Selection criteriaWe included RCTs, cluster-RCTs and quasi-RCTs comparing intermittent phototherapy with continuous phototherapy in jaundiced infants (both term and preterm) up to the age of 30 days. We compared intermittent phototherapy with continuous phototherapy by any method and at any dose and duration as defined by the authors.Data collection and analysisThree review authors independently selected trials, assessed trial quality and extracted data from included studies. We performed fixed-effect analyses and expressed treatment effects as mean difference (MD), risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CIs). Our primary outcomes of interest were rate of decline of serum bilirubin, and kernicterus. We used the GRADE approach to assess the certainty of evidence.Main resultsWe included 12 RCTs (1600 infants) in the review. There is one ongoing study and four awaiting classification. There was little or no difference between intermittent phototherapy and continuous phototherapy with respect to rate of decline of bilirubin in jaundiced newborn infants (MD -0.09 micromol/L/hr, 95% CI -0.21 to 0.03; I² = 61%; 10 studies; 1225 infants; low-certainty evidence). One study involving 60 infants reported no incidence of bilirubin induced brain dysfunction (BIND). It is uncertain whether either intermittent or continuous phototherapy reduces BIND because the certainty of this evidence is very low. There was little or no difference in treatment failure (RD 0.03, 95% CI 0.08 to 0.15; RR 1.63, 95% CI 0.29 to 9.17; 1 study; 75 infants; very low-certainty evidence) or infant mortality (RD -0.01, 95% CI -0.03 to 0.01; RR 0.69, 95% CI 0.37 to 1.31 I² = 0%; 10 studies, 1470 infants; low-certainty evidence). AUTHORS' CONCLUSIONS: The available evidence detected little or no difference between intermittent and continuous phototherapy with respect to rate of decline of bilirubin. Continuous phototherapy appears to be more effective in preterm infants, however, the risks of continuous phototherapy and the potential benefits of a slightly lower bilirubin level are unknown. Intermittent phototherapy is associated with a decrease in the total number of hours of phototherapy exposure. There are theoretical benefits to intermittent regimens but there are important safety outcomes that were inadequately addressed. Large, well designed, prospective trials are needed in both preterm and term infants before it can be concluded that intermittent and continuous phototherapy regimens are equally effective.

Project description:IntroductionIntravenous loop diuretics are a cornerstone of therapy in acutely decompensated heart failure (ADHF). We sought to determine if there are any differences in clinical outcomes between intravenous bolus and continuous infusion of loop diuretics.MethodsSubjects with ADHF within 12 hours of hospital admission were randomly assigned to continuous infusion or twice daily bolus therapy with furosemide. There were three co-primary endpoints assessed from admission to discharge: the mean paired changes in serum creatinine, estimated glomerular filtration rate (eGFR), and reduction in B-type natriuretic peptide (BNP). Secondary endpoints included the rate of acute kidney injury (AKI), change in body weight and six months follow-up evaluation after discharge.ResultsA total of 43 received a continuous infusion and 39 were assigned to bolus treatment. At discharge, the mean change in serum creatinine was higher (+0.8 ± 0.4 versus -0.8 ± 0.3 mg/dl P <0.01), and eGFR was lower (-9 ± 7 versus +5 ± 6 ml/min/1.73 m(2) P <0.05) in the continuous arm. There was no significant difference in the degree of weight loss (-4.1 ± 1.9 versus -3.5 ± 2.4 kg P = 0.23). The continuous infusion arm had a greater reduction in BNP over the hospital course, (-576 ± 655 versus -181 ± 527 pg/ml P = 0.02). The rates of AKI were comparable (22% and 15% P = 0.3) between the two groups. There was more frequent use of hypertonic saline solutions for hyponatremia (33% versus 18% P <0.01), intravenous dopamine infusions (35% versus 23% P = 0.02), and the hospital length of stay was longer in the continuous infusion group (14. 3 ± 5 versus 11.5 ± 4 days, P <0.03). At 6 months there were higher rates of re-admission or death in the continuous infusion group, 58% versus 23%, (P = 0.001) and this mode of treatment independently associated with this outcome after adjusting for baseline and intermediate variables (adjusted hazard ratio = 2.57, 95% confidence interval, 1.01 to 6.58 P = 0.04).ConclusionsIn the setting of ADHF, continuous infusion of loop diuretics resulted in greater reductions in BNP from admission to discharge. However, this appeared to occur at the consequence of worsened renal filtration function, use of additional treatment, and higher rates of rehospitalization or death at six months.Trial registrationClinicalTrials.gov NCT01441245. Registered 23 September 2011.

Project description:Intermittent (or bolus) feeding regimens in critically ill patients have been of increasing interest to clinicians and scientists. Changes in amino acid, fat and carbohydrate metabolites over time might yet deliver other benefits (e.g. modulation of the circadian rhythm and sleep, and impacts on ghrelin secretion, insulin resistance and autophagy). We set out to characterise these changes in metabolite concentration. The Intermittent versus Continuous Feeding in Critically Ill paitents study (NCT02358512) was an eight-centre single-blinded randomised controlled trial. Patients were randomised to received a continuous (control arm) or intermittent (6x/day, intervention arm) enteral feeding regimen. Blood samples were taken on trial days 1, 7 and 10 immediately before and 30 min after intermittent feeds, and at equivalent timepoints in the control arm. A pre-planned targeted metabolomic analysis was performend using Nuclear Resonance Spectroscopy. Five hundred and ninety four samples were analysed from 75 patients. A total of 24 amino acid-, 19 lipid based-, and 44 small molecule metabolite features. Across the main two axes of variation (40-60% and 6-8% of variance), no broad patterns distinguished between intermittent or continuous feeding arms, across intra-day sampling times or over the 10 days from initial ICU admission. Logfold decreases in abundance were seen in metabolites related to amino acids (Glutamine - 0.682; Alanine - 0.594), ketone body metabolism (Acetone - 0.64; 3-Hydroxybutyric Acid - 0.632; Acetonacetic Acid - 0.586), fatty acid (carnitine - 0.509) and carbohydrate metabolism ( Maltose - 0.510; Citric Acid - 0.485). 2-3 Butanediol, a by-product of sugar-fermenting microbial metabolism also decreased (- 0.489). No correlation was seen with change in quadriceps muscle mass for any of the 20 metabolites varying with time (all p > 0.05). Increasing severity of organ failure was related to increasing ketone body metabolism (3 Hydroxybutyric Acid-1 and - 3; p = 0.056 and p = 0.014), carnitine deficiency (p = 0.002) and alanine abundancy (p - 0.005). A 6-times a day intermittent feeding regimen did not alter metabolite patterns across time compared to continuous feeding in critically ill patients, either within a 24 h period or across 10 days of intervention. Future research on intermittent feeding regimens should focus on clinical process benefits, or extended gut rest and fasting.

Dataset Information

Intermittent Bolus Compared With Continuous Feeding Enhances Insulin and Amino Acid Signaling to Translation Initiation in Skeletal Muscle of Neonatal Pigs.

Background

Objectives

Methods

Results

Conclusions

Publications

Intermittent Bolus Compared With Continuous Feeding Enhances Insulin and Amino Acid Signaling to Translation Initiation in Skeletal Muscle of Neonatal Pigs.

Similar Datasets

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