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Abrahamse E, Thomassen GGM, Renes IB, Wierenga PA, Hettinga KA. Assessment of milk protein digestion kinetics: effects of denaturation by heat and protein type used. Food Funct 2022; 13:5715-5729. [PMID: 35522150 DOI: 10.1039/d2fo00542e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Knowledge about how molecular properties of proteins affect their digestion kinetics is crucial to understand protein postprandial plasma amino acid (AA) responses. Previously it was found that a native whey protein isolate (NWPI) and heat denatured whey protein isolate (DWPI) elicit comparable postprandial plasma AA peak concentrations in neonatal piglets, while a protein base ingredient for infant formula (PBI, a β-casein-native whey protein mixture) caused a 39% higher peak AA concentration than NWPI. We hypothesized that both whey protein denaturation by heat as well as changing protein composition by including β-casein, increases the rate of intact protein loss, and that changing the protein composition (by including β-casein), but not whey protein denaturation, yields a faster absorbable product release. Therefore NWPI (91% native), DWPI (91% denatured) and PBI hydrolysis was investigated in a semi-dynamic in vitro digestion model (SIM). NWPI and DWPI hydrolysis were also compared in a dynamic digestion model with dialysis (TIM-1) to exclude potential product inhibition effects that may occur in a closed vessel digestion model as SIM. In both models, the degree of hydrolysis (DH), loss of intact protein, and release of absorbable products (SIM: <0.5 kDa peptides and free AA, TIM-1: bioaccessible AA) were monitored. Additionally, in SIM, intermediate product amounts and their characteristics were determined. DWPI showed considerably faster intact protein loss, but similar DH and absorbable product release kinetics compared with NWPI in both models. Furthermore, more, relatively large, intermediate products were released from DWPI than from NWPI. PBI showed increased intact protein loss, similar DH, and absorbable product release kinetics, but more, relatively small, intermediate products than NWPI. In conclusion, both whey protein denaturation and β-casein inclusion increased the rate of intact protein loss without affecting absorbable product release during in vitro digestion. Our results suggest that intermediate digestion product characteristics are important in relation to postprandial AA responses.
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Affiliation(s)
- Evan Abrahamse
- Food Quality and Design, Wageningen University, Wageningen, Netherlands. .,Danone Nutricia Research, Utrecht, Netherlands
| | | | - Ingrid B Renes
- Danone Nutricia Research, Utrecht, Netherlands.,Department of Pediatrics, Emma Children's Hospital, Amsterdam UMC, Amsterdam, Netherlands
| | - Peter A Wierenga
- Laboratory of Food Chemistry, Wageningen University, Wageningen, Netherlands
| | - Kasper A Hettinga
- Food Quality and Design, Wageningen University, Wageningen, Netherlands.
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2
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The effects of glucagon and the target of rapamycin (TOR) on skeletal muscle protein synthesis and age-dependent sarcopenia in humans. Clin Nutr ESPEN 2021; 44:15-25. [PMID: 34330459 DOI: 10.1016/j.clnesp.2021.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND AIMS Human target of rapamycin (TOR) is a kinase that stimulates protein synthesis in the skeletal muscle in response to amino acids and physical activity. METHODS A comprehensive literature search was conducted on the PubMed database from its inception up to May 2021 to retrieve information on the effects of TOR and glucagon on muscle function. Articles written in English regarding human subjects were included. RESULTS l-leucine activates TOR to initiate protein synthesis in the skeletal muscle. Glucagon has a crucial role suppressing skeletal muscle protein synthesis by increasing l-leucine oxidation and the irreversible loss of this amino acid. Glucagon-induced l-leucine oxidation suppresses TOR and attenuates the ability of skeletal muscle to synthesize proteins. Conditions associated with increased glucagon secretion typically feature reduced ability to synthesize proteins in the skeletal muscle that may evolve into sarcopenia. Animal protein ingestion, unlike vegetable protein, stimulates glucagon secretion. High intake of animal protein increases l-leucine oxidation and promotes the use of amino acids as fuel. Sarcopenia and arterial stiffness characteristically occur together in conditions featuring insulin resistance, such as aging. Insulin resistance mediates the relationship between aging and sarcopenia and arterial stiffness. The loss of skeletal muscle fibers that characterizes sarcopenia is followed by collagen and lipid accumulation. Likewise, insulin resistance is associated with arterial stiffness and intima-media thickening due to adaptive accretion of collagen and lipids in the arterial wall. CONCLUSIONS Human TOR participates in the pathogenesis of sarcopenia and arterial stiffness, although its effects remain to be fully elucidated.
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Important determinants to take into account to optimize protein nutrition in the elderly: solutions to a complex equation. Proc Nutr Soc 2020; 80:207-220. [PMID: 33198824 DOI: 10.1017/s0029665120007934] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
During ageing, skeletal muscle develops anabolic resistance towards the stimulation of protein synthesis induced by dietary amino acids. The stimulation of muscle protein synthesis after food intake remains insufficient, even with a protein intake recommended for healthy adults. This alteration is one of the mechanisms known to be responsible for the decrease of muscle mass and function during ageing, namely sarcopenia. Increasing dietary protein intake above the current RDA(0⋅83 g/kg/d) has been strongly suggested to overcome the anabolic resistance observed. It is also specified that the dietary protein ingested should be of good quality. A protein of good quality is a protein whose amino acid (AA) composition covers the requirement of each AA when ingested at the RDA. However, the biological value of proteins may vary among dietary sources in which AA composition could be unbalanced. In the present review, we suggest that the quality of a dietary protein is also related to several other determinants. These determinants include the speed of digestion of dietary proteins, the presence of specific AA, the food matrix in which the dietary proteins are included, the processes involved in the production of food products (milk gelation and cooking temperature), the energy supply and its nature, and the interaction between nutrients before ingestion. Particular attention is given to plant proteins for nutrition of the elderly. Finally, the timing of protein intake and its association with the desynchronized intake of energetic nutrients are discussed.
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The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients. PLoS One 2019; 14:e0219756. [PMID: 31412042 PMCID: PMC6693779 DOI: 10.1371/journal.pone.0219756] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 07/01/2019] [Indexed: 01/15/2023] Open
Abstract
Background This retrospective study had two main aims: (1) to document possible correlations between plasma Amino Acids (AAs) and circulating Albumin (Alb) and Haemoglobin (Hb); and (2) to identify which AAs were predictors of Alb and Hb. Methods The study considered 125 stroke subjects (ST) (61.6% males; 65.6 +/- 14.9 years) who met the eligibility criteria (absence of co morbidities associated with altered plasma AAs and presence of plasma AAs determined after overnight fasting). Fifteen matched healthy subjects with measured plasma AAs served as controls. Results The best correlations of Alb were with tryptophan (Trp) and histidine (His) (r = + 0.53; p < 0.0001), and those of Hb were with histidine (r = +0.47) and Essential AAs (r = +0.47) (both p<0.0001). In multivariate analysis, Trp (p< 0.0001) and His (p = 0.01) were shown to be the best positive predictors of Alb, whereas glutamine (p = 0.006) was the best positive predictor of Hb. Conclusions The study shows that the majority of plasma AAs were positively correlated with Alb and Hb. The best predictors of circulating Alb and Hb were the levels of tryptophan and glutamine, respectively.
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5
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Berrazaga I, Micard V, Gueugneau M, Walrand S. The Role of the Anabolic Properties of Plant- versus Animal-Based Protein Sources in Supporting Muscle Mass Maintenance: A Critical Review. Nutrients 2019; 11:E1825. [PMID: 31394788 PMCID: PMC6723444 DOI: 10.3390/nu11081825] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 02/06/2023] Open
Abstract
Plant-sourced proteins offer environmental and health benefits, and research increasingly includes them in study formulas. However, plant-based proteins have less of an anabolic effect than animal proteins due to their lower digestibility, lower essential amino acid content (especially leucine), and deficiency in other essential amino acids, such as sulfur amino acids or lysine. Thus, plant amino acids are directed toward oxidation rather than used for muscle protein synthesis. In this review, we evaluate the ability of plant- versus animal-based proteins to help maintain skeletal muscle mass in healthy and especially older people and examine different nutritional strategies for improving the anabolic properties of plant-based proteins. Among these strategies, increasing protein intake has led to a positive acute postprandial muscle protein synthesis response and even positive long-term improvement in lean mass. Increasing the quality of protein intake by improving amino acid composition could also compensate for the lower anabolic potential of plant-based proteins. We evaluated and discussed four nutritional strategies for improving the amino acid composition of plant-based proteins: fortifying plant-based proteins with specific essential amino acids, selective breeding, blending several plant protein sources, and blending plant with animal-based protein sources. These nutritional approaches need to be profoundly examined in older individuals in order to optimize protein intake for this population who require a high-quality food protein intake to mitigate age-related muscle loss.
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Affiliation(s)
- Insaf Berrazaga
- UNH, Unité de Nutrition Humaine, CRNH, Université Clermont Auvergne, INRA, Auvergne, 63000 Clermont-Ferrand, France
- IATE Agropolymer Engineering and Emerging Technologies, Univ. Montpellier, INRA, CIRAD, Montpellier SupAgro, 34060 Montpellier, France
| | - Valérie Micard
- IATE Agropolymer Engineering and Emerging Technologies, Univ. Montpellier, INRA, CIRAD, Montpellier SupAgro, 34060 Montpellier, France
| | - Marine Gueugneau
- UNH, Unité de Nutrition Humaine, CRNH, Université Clermont Auvergne, INRA, Auvergne, 63000 Clermont-Ferrand, France
| | - Stéphane Walrand
- UNH, Unité de Nutrition Humaine, CRNH, Université Clermont Auvergne, INRA, Auvergne, 63000 Clermont-Ferrand, France.
- Service de Nutrition Clinique, Centre Hospitalier Universitaire (CHU) Gabriel Montpied, 63000 Clermont-Ferrand, France.
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Liao YH, Chen CN, Hu CY, Tsai SC, Kuo YC. Soymilk ingestion immediately after therapeutic exercise enhances rehabilitation outcomes in chronic stroke patients: A randomized controlled trial. NeuroRehabilitation 2019; 44:217-229. [PMID: 30856124 DOI: 10.3233/nre-182574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE This study investigates the effects of an 8-weeks rehabilitation exercise plus soymilk ingestion immediately after exercise on functional outcomes in chronic stroke patients. METHODS Twenty-two stroke patients (age: 57-84 yrs; time since stroke onset: 2-19 yrs) participated and completed the study. A randomized, placebo-controlled and double-blind design was used. Participants were randomly allocated to either soymilk (SMS; n = 11) or placebo (PLA; n = 11) group and received identical 8-weeks rehabilitation intervention (3 sessions/week; 120 min/session) with corresponding treatment beverages. The physical and functional outcomes were evaluated before, during, and after the intervention. RESULTS The 8-weeks rehabilitation program enhanced functional outcomes of participants. The immediate soymilk ingestion after exercise additionally improved hand grip strength (p = 0.021), 8-feet walking speed (p = 0.019), walking performance per unit lean mass (p = 0.024), and 6-minute walk performance (6MWT, p = 0.016) compared with PLA after the intervention. However, the improvements in the total score for short physical performance battery (SPPB) and lean mass did not differ between groups. CONCLUSION Compared with rehabilitation alone, the 8-week rehabilitation program combined with immediate soymilk ingestion further improved walking speed, exercise endurance, grip strength, and muscle functionality in chronic stroke patients.
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Affiliation(s)
- Yi-Hung Liao
- Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Chiao-Nan Chen
- Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Yueh Hu
- Department of Rehabilitation, Yuanshan and Suao Branch, Taipei Veterans General Hospital, Suao Township, Yilan County, Taiwan
| | - Shiow-Chwen Tsai
- Institute of Sports Sciences, University of Taipei, Taipei, Taiwan
| | - Yu-Chi Kuo
- Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
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Rondanelli M, Peroni G, Gasparri C, Infantino V, Nichetti M, Cuzzoni G, Spadaccini D, Perna S. Is a Combination of Melatonin and Amino Acids Useful to Sarcopenic Elderly Patients? A Randomized Trial. Geriatrics (Basel) 2018; 4:geriatrics4010004. [PMID: 31023972 PMCID: PMC6473373 DOI: 10.3390/geriatrics4010004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/12/2018] [Accepted: 12/21/2018] [Indexed: 12/16/2022] Open
Abstract
This study evaluated the effectiveness of a 4-week intervention of melatonin and essential aminoacid supplementation on body composition, protein metabolism, strength and inflammation in 159 elderly sarcopenic patients (42/117, men/women), assigned to four groups: isocaloric placebo (P, n = 44), melatonin (M, 1 mg/daily, n = 42), essential amino acids (eAA 4 g/daily, n = 40) or eAA plus melatonin (eAAM, 4 g eAA and 1 mg melatonin/daily, n = 30). Data from body composition (dual X-ray absortiometry (DXA)), strength (handgrip test) and biochemical parameters for the assessment of protein metabolism (albumin) and inflammation (CRP) were collected at baseline and after the 4-week intervention. Compared with P and M, supplementation with eAA plus M increased total fat-free mass (vs. P: +2190 g; p < 0.01; vs. M: +2107 g; p < 0.05). M alone lowered albumin levels (vs. P: −0.39 g; p < 0.01; vs. eAA: −0.47 g; p < 0.01). This data on albumin was confirmed by within-group analysis (M −0.44g; p < 0.001; eAAM: −0.34 p < 0.05). M and eAA seemed to lower the percentage of gynoid fat (p < 0.05) and android fat (p < 0.01). No significant changes in inflammation or strength were reported. A 4-week intervention with eAA plus M together may be effective in enhancing fat-free-mass compared to M and P but not versus eAA. M alone demonstrates a negative effect on albumin level.
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Affiliation(s)
- Mariangela Rondanelli
- IRCCS Mondino Foundation, 27100 Pavia, Italy.
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
| | - Gabriella Peroni
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
| | - Clara Gasparri
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
| | - Vittoria Infantino
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
- Department of Biomedical Science and Human Oncology, University of Bari, 70121 Bari, Italy.
| | - Mara Nichetti
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
| | | | - Daniele Spadaccini
- Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, 27100 Pavia, Italy.
| | - Simone Perna
- Department of Biology, College of Science, University of Bahrain, Sakhir Campus P.O. Box 32038, Kingdom of Bahrain.
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The fractional synthesis rates of plasma proteins as determined using deuterated water are sensitive to dietary intake of lysine in rats. Amino Acids 2018; 50:1719-1727. [DOI: 10.1007/s00726-018-2645-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/27/2018] [Indexed: 11/26/2022]
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St-Jules DE, Goldfarb DS, Popp CJ, Pompeii ML, Liebman SE. Managing protein-energy wasting in hemodialysis patients: A comparison of animal- and plant-based protein foods. Semin Dial 2018; 32:41-46. [DOI: 10.1111/sdi.12737] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- David E. St-Jules
- Division of Health and Behavior, Department of Population Health; New York University School of Medicine; New York NY USA
| | - David S. Goldfarb
- Division of Nephrology, Department of Medicine; New York University School of Medicine; New York NY USA
| | - Collin J. Popp
- Division of Health and Behavior, Department of Population Health; New York University School of Medicine; New York NY USA
| | - Mary Lou Pompeii
- Division of Health and Behavior, Department of Population Health; New York University School of Medicine; New York NY USA
| | - Scott E. Liebman
- Division of Nephrology, Department of Medicine; University of Rochester School of Medicine; Rochester NY USA
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10
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Association of plasma free amino acids with hyperuricemia in relation to diabetes mellitus, dyslipidemia, hypertension and metabolic syndrome. Sci Rep 2017; 7:17616. [PMID: 29247200 PMCID: PMC5732272 DOI: 10.1038/s41598-017-17710-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022] Open
Abstract
Previous studies demonstrated independent contributions of plasma free amino acids (PFAAs) and high uric acid (UA) concentrations to increased risks of lifestyle-related diseases (LSRDs), but the important associations between these factors and LSRDs remain unknown. We quantified PFAAs and UA amongst Japanese subjects without LSRDs (no-LSRD, n = 2805), and with diabetes mellitus (DM, n = 415), dyslipidemia (n = 3207), hypertension (n = 2736) and metabolic syndrome (MetS, n = 717). The concentrations of most amino acids differed significantly between the subjects with and without hyperuricemia (HU) and also between the no-LSRD and LSRD groups (p < 0.05 to 0.001). After adjustment, the logistic regression analyses revealed that lysine in DM, alanine, proline and tyrosine in dyslipidemia, histidine, lysine and ornithine in hypertension, and lysine and tyrosine in MetS demonstrated significant positive associations with HU among the patients with LSRDs only (p < 0.05 to 0.005). By contrast, arginine, asparagine and threonine showed significant inverse associations with HU in the no-LSRD group only (p < 0.05 to 0.01). For the first time, we provide evidence for distinct patterns of association between PFAAs and HU in LSRDs, and postulate the possibility of interplay between PFAAs and UA in their pathophysiology.
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Dalle S, Rossmeislova L, Koppo K. The Role of Inflammation in Age-Related Sarcopenia. Front Physiol 2017; 8:1045. [PMID: 29311975 PMCID: PMC5733049 DOI: 10.3389/fphys.2017.01045] [Citation(s) in RCA: 339] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/29/2017] [Indexed: 12/25/2022] Open
Abstract
Many physiological changes occur with aging. These changes often, directly or indirectly, result in a deterioration of the quality of life and even in a shortening of life expectancy. Besides increased levels of reactive oxygen species, DNA damage and cell apoptosis, another important factor affecting the aging process involves a systemic chronic low-grade inflammation. This condition has already been shown to be interrelated with several (sub)clinical conditions, such as insulin resistance, atherosclerosis and Alzheimer's disease. Recent evidence, however, shows that chronic low-grade inflammation also contributes to the loss of muscle mass, strength and functionality, referred to as sarcopenia, as it affects both muscle protein breakdown and synthesis through several signaling pathways. Classic interventions to counteract age-related muscle wasting mainly focus on resistance training and/or protein supplementation to overcome the anabolic inflexibility from which elderly suffer. Although the elderly benefit from these classic interventions, the therapeutic potential of anti-inflammatory strategies is of great interest, as these might add up to/support the anabolic effect of resistance exercise and/or protein supplementation. In this review, the molecular interaction between inflammation, anabolic sensitivity and muscle protein metabolism in sarcopenic elderly will be addressed.
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Affiliation(s)
- Sebastiaan Dalle
- Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Leuven, Belgium
| | - Lenka Rossmeislova
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Katrien Koppo
- Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Leuven, Belgium
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Dumitrescu G, Komaromi A, Rooyackers O, Klaude M, Hebert C, Wernerman J, Norberg Å. Repeated quantitative measurements of De Novo synthesis of albumin and fibrinogen. PLoS One 2017; 12:e0174611. [PMID: 28350862 PMCID: PMC5370154 DOI: 10.1371/journal.pone.0174611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/13/2017] [Indexed: 11/18/2022] Open
Abstract
The possibility of using two different isotopomers, for the incorporation of isotopically labeled amino acids, was explored to enable longitudinal studies of de novo synthesis of two export liver proteins, albumin and fibrinogen. The agreement of the synthesis rates between the two different labels was evaluated along with the reproducibility of repeated experiments using different time intervals. Healthy volunteers were studied in a standardized fed state. Protocol A (n = 10) involved two measurements 48 hours apart. Protocol B (n = 6) involved three measurements at baseline and five hours and then seven days after the initial measurement. De novo synthesis of albumin and fibrinogen by the incorporation of D5-phenylalanine or D8-phenylalanine were measured using the flooding dose technique. Albumin and fibrinogen were isolated from plasma using standard techniques. Fractional and absolute synthesis rates were calculated. Repeated measurements employing the two isotoptomers showed good agreement for albumin fractional synthesis rate after 48 hours (p = 0.92) and after 7 days (p = 0.99), with a coefficient of variation of 5.9% when using the same isotopic label. For fibrinogen, the coefficient of variation for the fractional synthesis rate employing the same isotopic label was 16.6%. Repeated measurements after 48 hours and seven days showed less agreement although there was no statistical difference (P = 0.32 and P = 0.30 respectively). Repeated measurement after five hours showed a statistical significant difference for the fractional synthesis rate of fibrinogen (p = 0.008) but not for albumin (p = 0.12). Repeated measurements of albumin de novo synthesis more than 48 hours apart show acceptable agreement using either one or two different isotopic labels. For fibrinogen the larger intra-individual scatter necessitates larger study groups to detect changes in longitudinal studies. Repeated measurements within 48 hours need to be validated further.
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Affiliation(s)
- Gabriel Dumitrescu
- Department of Anesthesia and Intensive Care Medicine at Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Andras Komaromi
- Department of Anesthesia and Intensive Care Medicine at Karolinska University Hospital, Stockholm, Sweden
| | - Olav Rooyackers
- Department of Anesthesia and Intensive Care Medicine at Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Maria Klaude
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Christina Hebert
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Jan Wernerman
- Department of Anesthesia and Intensive Care Medicine at Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Åke Norberg
- Department of Anesthesia and Intensive Care Medicine at Karolinska University Hospital, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology CLINTEC, Karolinska Institutet, Stockholm, Sweden
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13
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Rittler P, Schiefer B, Demmelmair H, Koletzko B, Roscher AA, Jacobs R, Krick M, Jauch KW, Hartl WH. Effect of Amino Acid Infusion on Human Postoperative Colon Protein Synthesisin Situ. JPEN J Parenter Enteral Nutr 2017; 29:255-61. [PMID: 15961681 DOI: 10.1177/0148607105029004255] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Amino acids are an integral part of parenteral nutrition because of their anabolic action helping to conserve body protein after surgical stress. At the gastrointestinal tract, an adequate supply of amino acids may be particularly important because of the gut's high rate of protein turnover, cell division, and proliferation. However, no information is available about the effects of amino acids on human intestinal protein metabolism after surgery. METHODS Studies were performed in postabsorptive patients 8-10 days after major abdominal surgery. Mass spectrometry techniques (capillary gas chromatography/combustion isotope ratio mass spectrometry) were used to directly determine the incorporation rate of 1-[13C]-leucine into colon mucosal protein. All subjects had a colostomy, which allowed easy access to the colon mucosa, and consecutive sampling from the same tissue was performed during continuous isotope infusion (0.16 micromol/kg min). Isotopic enrichments were determined at baseline and after a 4-hour infusion of amino acids or after infusion of saline (control group). RESULTS Compared with baseline, infusion of amino acids reduced fractional colon protein synthesis significantly by -29.2 +/- 8.3%. This decrease was also significantly different from the corresponding (insignificant) change during saline infusion (+19.4 +/- 26.9%, p < .05 vs amino acid group). CONCLUSIONS After surgery, an amino acid infusion acutely reduces postoperative colon protein synthesis. This effect possibly may be attributed to interactions of specific amino acids (glutamine) with an altered intestinal immune system and enterocyte activity.
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Affiliation(s)
- Peter Rittler
- Department of Surgery, Klinikum Grosshadern, Munich, Germany
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14
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De Bandt JP. Leucine and Mammalian Target of Rapamycin-Dependent Activation of Muscle Protein Synthesis in Aging. J Nutr 2016; 146:2616S-2624S. [PMID: 27934653 DOI: 10.3945/jn.116.234518] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/11/2016] [Accepted: 06/15/2016] [Indexed: 12/17/2022] Open
Abstract
The preservation or restoration of muscle mass is of prime importance for healthy aging. However, aging has been repeatedly shown to be associated with resistance of muscle to the anabolic effects of feeding. Leucine supplementation has been proposed as a possible strategy because of its regulatory role on protein homeostasis. Indeed, it acts independently of growth factors and leads to enhanced cap-dependent mRNA translation initiation and increased protein synthesis. Leucine acts as a signaling molecule directly at the muscle level via the activation of mammalian/mechanistic target of rapamycin complex 1 (mTORC1). However, in aged muscle, mTORC1 activation seems to be impaired, with decreased sensitivity and responsiveness of muscle protein synthesis to amino acids, whereas the phosphorylation state of several components of this signaling pathway appears to be higher in the basal state. This may stem from specific age-related impairment of muscle signaling and from decreased nutrient and growth factor delivery to the muscle. Whether aging per se affects mTORC1 signaling remains to be established, because aging is frequently associated with inadequate protein intake, decreased insulin sensitivity, inactivity, inflammatory processes, etc. Whatever its origin, this anabolic resistance to feeding can be mitigated by quantitative and qualitative manipulation of protein supply, such as leucine supplementation; however, there remains the question of possible adverse effects of long-term, high-dose leucine supplementation in terms of insulin resistance and tumorigenesis.
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Affiliation(s)
- Jean-Pascal De Bandt
- EA4466 PRETRAM, Nutrition Biology Laboratory, Faculty of Pharmacy, Paris Descartes University, Sorbonne Paris Cité, Paris, France
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15
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Nutritional regulation of the anabolic fate of amino acids within the liver in mammals: concepts arising from in vivo studies. Nutr Res Rev 2016; 28:22-41. [PMID: 26156215 DOI: 10.1017/s0954422415000013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
At the crossroad between nutrient supply and requirements, the liver plays a central role in partitioning nitrogenous nutrients among tissues. The present review examines the utilisation of amino acids (AA) within the liver in various physiopathological states in mammals and how the fates of AA are regulated. AA uptake by the liver is generally driven by the net portal appearance of AA. This coordination is lost when demands by peripheral tissues is important (rapid growth or lactation), or when certain metabolic pathways within the liver become a priority (synthesis of acute-phase proteins). Data obtained in various species have shown that oxidation of AA and export protein synthesis usually responds to nutrient supply. Gluconeogenesis from AA is less dependent on hepatic delivery and the nature of nutrients supplied, and hormones like insulin are involved in the regulatory processes. Gluconeogenesis is regulated by nutritional factors very differently between mammals (glucose absorbed from the diet is important in single-stomached animals, while in carnivores, glucose from endogenous origin is key). The underlying mechanisms explaining how the liver adapts its AA utilisation to the body requirements are complex. The highly adaptable hepatic metabolism must be capable to deal with the various nutritional/physiological challenges that mammals have to face to maintain homeostasis. Whereas the liver responds generally to nutritional parameters in various physiological states occurring throughout life, other complex signalling pathways at systemic and tissue level (hormones, cytokines, nutrients, etc.) are involved additionally in specific physiological/nutritional states to prioritise certain metabolic pathways (pathological states or when nutritional requirements are uncovered).
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Liebau F, Jensen MD, Nair KS, Rooyackers O. Upper-body obese women are resistant to postprandial stimulation of protein synthesis. Clin Nutr 2014; 33:802-7. [PMID: 24269078 PMCID: PMC4019711 DOI: 10.1016/j.clnu.2013.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 10/18/2013] [Accepted: 11/01/2013] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Upper-body, i.e. visceral, obesity is associated with insulin resistance and impaired protein synthesis. It is unclear whether postprandial stimulation of protein synthesis is affected by body fat distribution. We investigated the postprandial protein anabolic response in a cohort of obese women. METHODS Participants were studied after an overnight fast and after a mixed meal, grouped as upper-body obese (UBO, waist-to-hip ratio, WHR, >0.85, n = 6) vs. lower-body obese (LBO, WHR <0.80, n = 7). Lipid and carbohydrate metabolism were assessed by measurements of plasma free fatty acids (FFA), insulin and glucose plasma concentrations, and calculation of the Quicki index from fasting glucose and insulin values. Different labels of stable isotopes of phenylalanine were administered intravenously and orally, and leg and whole-body protein breakdown and synthesis were calculated from phenylalanine/tyrosine isotopic enrichments in femoral arterial and venous blood, using equations for steady-state kinetics. Data are denoted as mean ± SD. RESULTS Age (38 vs. 40, p = 0.549) and body-mass index (33.7 ± 1.9 vs. 35.0 ± 1.8, p = 0.241) were similar in both groups. UBO subjects had more visceral fat (p = 0.002) and higher fat-free body mass (FFM) (p = 0.015). Plasma insulin concentrations were greater in UBO than LBO women (p = 0.013), and UBO were less insulin sensitive (Quicki = 0.32 ± 0.01 vs. 0.36 ± 0.02, p = 0.005). Protein kinetics across the leg were not different between groups. Fasting whole body protein balance was similarly negative in both groups (UBO -6.5 ± 2.4 vs. LBO -7.6 ± 0.9 μmol/kgFFM/h, p = 1.0). Postprandially, whole body protein balance became less positive in UBO than in LBO (14.8 ± 3.7 vs. 20.2 ± 3.7 μmol/kgFFM/h, p = 0.017). CONCLUSIONS Whole-body protein balance following a meal is less positive in upper-body obese, insulin-resistant, women than in lower-body obese women.
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Affiliation(s)
- Felix Liebau
- Department of Anesthesiology and Intensive Care, Karolinska University Hospital Huddinge and Karolinska Institutet, Stockholm, Sweden.
| | | | | | - Olav Rooyackers
- Department of Anesthesiology and Intensive Care, Karolinska University Hospital Huddinge and Karolinska Institutet, Stockholm, Sweden.
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Savary-Auzeloux I, Magne H, Migné C, Oberli M, Breuillé D, Faure M, Vidal K, Perrot M, Rémond D, Combaret L, Dardevet D. A dietary supplementation with leucine and antioxidants is capable to accelerate muscle mass recovery after immobilization in adult rats. PLoS One 2013; 8:e81495. [PMID: 24312309 PMCID: PMC3843669 DOI: 10.1371/journal.pone.0081495] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/14/2013] [Indexed: 11/18/2022] Open
Abstract
Prolonged inactivity induces muscle loss due to an activation of proteolysis and decreased protein synthesis; the latter is also involved in the recovery of muscle mass. The aim of the present work was to explore the evolution of muscle mass and protein metabolism during immobilization and recovery and assess the effect of a nutritional strategy for counteracting muscle loss and facilitating recovery. Adult rats (6–8 months) were subjected to unilateral hindlimb casting for 8 days (I0–I8) and then permitted to recover for 10 to 40 days (R10–R40). They were fed a Control or Experimental diet supplemented with antioxidants/polyphenols (AOX) (I0 to I8), AOX and leucine (AOX + LEU) (I8 to R15) and LEU alone (R15 to R40). Muscle mass, absolute protein synthesis rate and proteasome activities were measured in gastrocnemius muscle in casted and non-casted legs in post prandial (PP) and post absorptive (PA) states at each time point. Immobilized gastrocnemius protein content was similarly reduced (-37%) in both diets compared to the non-casted leg. Muscle mass recovery was accelerated by the AOX and LEU supplementation (+6% AOX+LEU vs. Control, P<0.05 at R40) due to a higher protein synthesis both in PA and PP states (+23% and 31% respectively, Experimental vs. Control diets, P<0.05, R40) without difference in trypsin- and chymotrypsin-like activities between diets. Thus, this nutritional supplementation accelerated the recovery of muscle mass via a stimulation of protein synthesis throughout the entire day (in the PP and PA states) and could be a promising strategy to be tested during recovery from bed rest in humans.
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Affiliation(s)
- Isabelle Savary-Auzeloux
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
- * E-mail:
| | - Hugues Magne
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
| | - Carole Migné
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
| | - Marion Oberli
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
| | - Denis Breuillé
- Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland
| | - Magali Faure
- Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland
| | - Karine Vidal
- Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland
| | - Marie Perrot
- Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland
| | - Didier Rémond
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
| | - Lydie Combaret
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
| | - Dominique Dardevet
- Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, Clermont-Ferrand, France
- INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France
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Dardevet D, Rémond D, Peyron MA, Papet I, Savary-Auzeloux I, Mosoni L. Muscle wasting and resistance of muscle anabolism: the "anabolic threshold concept" for adapted nutritional strategies during sarcopenia. ScientificWorldJournal 2012; 2012:269531. [PMID: 23326214 PMCID: PMC3541599 DOI: 10.1100/2012/269531] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/03/2012] [Indexed: 01/06/2023] Open
Abstract
Skeletal muscle loss is observed in several physiopathological situations. Strategies to prevent, slow down, or increase recovery of muscle have already been tested. Besides exercise, nutrition, and more particularly protein nutrition based on increased amino acid, leucine or the quality of protein intake has generated positive acute postprandial effect on muscle protein anabolism. However, on the long term, these nutritional strategies have often failed in improving muscle mass even if given for long periods of time in both humans and rodent models. Muscle mass loss situations have been often correlated to a resistance of muscle protein anabolism to food intake which may be explained by an increase of the anabolic threshold toward the stimulatory effect of amino acids. In this paper, we will emphasize how this anabolic resistance may affect the intensity and the duration of the muscle anabolic response at the postprandial state and how it may explain the negative results obtained on the long term in the prevention of muscle mass. Sarcopenia, the muscle mass loss observed during aging, has been chosen to illustrate this concept but it may be kept in mind that it could be extended to any other catabolic states or recovery situations.
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Affiliation(s)
- Dominique Dardevet
- Clermont Université and Unité de Nutrition Humaine, Université d'Auvergne, BP 10448, 63000 Clermont-Ferrand, France.
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Abstract
It is well known that any quantitative (energy and protein levels) and qualitative (nature of the diet, nutrient dynamic) changes in the feeding of animals affect metabolism. Energy expenditure and feed efficiency at the whole-body level, nutrient partitioning between and within tissues and organs and, ultimately, tissue and organ characteristics are the major regulated traits with consequences on the quality of the meat and milk produced. Recent progress in biology has brought to light important biological mechanisms which explain these observations: for instance, regulation by the nutrients of gene expression or of key metabolic enzyme activity, interaction and sometimes cross-regulation or competition between nutrients to provide free energy (ATP) to living cells, indirect action of nutrients through a complex hormonal action, and, particularly in herbivores, interactions between trans-fatty acids produced in the rumen and tissue metabolism. One of the main targets of this nutritional regulation is a modification of tissue insulin sensitivity and hence of insulin action. In addition, the nutritional control of mitochondrial activity (and hence of nutrient catabolism) is another major mechanism by which nutrients may affect body composition and tissue characteristics. These regulations are of great importance in the most metabolically active tissues (the digestive tract and the liver) and may have undesirable (i.e. diabetes and obesity in humans) or desirable consequences (such as the production of fatty liver by ducks and geese, and the production of fatty and hence tasty meat or milk with an adapted fatty acid profile).
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Geukers VG, Li Z, Ackermans MT, Bos AP, Jinfeng L, Sauerwein HP. High-carbohydrate/low-protein-induced hyperinsulinemia does not improve protein balance in children after cardiac surgery. Nutrition 2012; 28:644-50. [PMID: 22261573 DOI: 10.1016/j.nut.2011.09.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 07/03/2011] [Accepted: 09/27/2011] [Indexed: 11/17/2022]
Abstract
OBJECTIVE In pediatric cardiac surgery, fluid-restricted low-protein (LoProt) diets account for cumulative protein deficits with increased morbidity. In this setting, we aimed to inhibit proteolysis by a high-carbohydrate (HiCarb)-intake-induced hyperinsulinemia and improve protein balance. METHODS The effect of a HiCarb/LoProt (glucose 10 mg · kg(-1) · min(-1)/protein 0.7 g · kg(-1) · d(-1)) versus a normal-carbohydrate (NormCarb)/LoProt (glucose 7.5 mg · kg(-1) · min(-1)/protein 0.3 g · kg(-1) · d(-1)) enteral diet on whole-body protein breakdown and balance was compared in a prospective, randomized, single-blinded trial in 24 children after cardiac surgery. On the second postoperative day, plasma insulin and amino acid concentrations, protein breakdown (endogenous rate of appearance of valine), protein synthesis (non-oxidative disposal of valine), protein balance, and the rate of appearance of urea were measured by using an isotopic infusion of [1-(13)C]valine and [(15)N(2)]urea. RESULTS The HiCarb/LoProt diet led to a serum insulin concentration that was three times higher than the NormCarb/LoProt diet (596 pmol/L, 80-1833, and 198 pmol/L, 76-1292, respectively, P = 0.02), without differences in plasma glucose concentrations. There were no differences in plasma amino acid concentrations, non-oxidative disposal of valine, and endogenous rate of appearance of valine between the groups, with a negative valine balance in the two groups (-0.65 μmol · kg(-1) · min(-1), -1.91 to 0.01, and -0.58 μmol · kg(-1) · min(-1), -2.32 to -0.07, respectively, P = 0.71). The serum cortisol concentration in the HiCarb/LoProt group was lower compared with the NormCarb/LoProt group (204 nmol/L, 50-544, and 532 nmol/L, 108-930, respectively, P = 0.02). CONCLUSION In children with fluid restriction after cardiac surgery, a HiCarb/LoProt diet compared with a NormCarb/LoProt diet stimulates insulin secretion but does not inhibit proteolysis further and therefore cannot be advocated for this purpose.
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Affiliation(s)
- Vincent G Geukers
- Pediatric Intensive Care Department, Emma Children's Hospital/Academic Medical Center, Amsterdam, Netherlands.
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Abstract
Protein-energy wasting (PEW), which is manifested by low serum levels of albumin or prealbumin, sarcopenia and weight loss, is one of the strongest predictors of mortality in patients with chronic kidney disease (CKD). Although PEW might be engendered by non-nutritional conditions, such as inflammation or other comorbidities, the question of causality does not refute the effectiveness of dietary interventions and nutritional support in improving outcomes in patients with CKD. The literature indicates that PEW can be mitigated or corrected with an appropriate diet and enteral nutritional support that targets dietary protein intake. In-center meals or oral supplements provided during dialysis therapy are feasible and inexpensive interventions that might improve survival and quality of life in patients with CKD. Dietary requirements and enteral nutritional support must also be considered in patients with CKD and diabetes mellitus, in patients undergoing peritoneal dialysis, renal transplant recipients, and in children with CKD. Adjunctive pharmacological therapies, such as appetite stimulants, anabolic hormones, and antioxidative or anti-inflammatory agents, might augment dietary interventions. Intraperitoneal or intradialytic parenteral nutrition should be considered for patients with PEW whenever enteral interventions are not possible or are ineffective. Controlled trials are needed to better assess the effectiveness of in-center meals and oral supplements.
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Albumin synthesis rates in post-surgical infants and septic adolescents; influence of amino acids, energy, and insulin. Clin Nutr 2011; 30:469-77. [PMID: 21367495 DOI: 10.1016/j.clnu.2011.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 01/26/2011] [Accepted: 02/03/2011] [Indexed: 01/25/2023]
Abstract
BACKGROUND & AIMS To investigate the effects of glucose, parenteral amino acids, and intravenous insulin on albumin synthesis rates in critically ill children. METHODS Two studies were performed in 8 post-surgical infants (age 9.8 ± 1.9 months; weight 9.5 ± 1.1 kg) and 9 septic adolescents (age 15 ± 1 yr; BMI 23 ± 4 kg m(-2)), respectively. All received a primed, constant, tracer infusion with [1-(13)C]Leucine. The infants in study 1 were randomized to receive low (2.5 mg kg(-1) min(-1)) and standard (5.0 mg kg(-1) min(-1)) glucose intake in a cross-over setting of two periods of 4 h each. The adolescents in study 2 were randomized to receive total parenteral nutrition with standard (1.5 g kg(-1) day(-1)) and high (3.0 g kg(-1) day(-1)) amino acid intake in a two day cross-over setting. On both study days, during the last 3 h of the tracer study, they received insulin infused at 80 mU m(-2) min(-1). RESULTS The post-surgical infants and the septic adolescents were mildly hypoalbuminemic (∼2.5 g dL(-1)) with high synthesis rates, which were not affected by different intakes of glucose, amino acids, or insulin infusion. CONCLUSIONS Albumin synthesis rates in hypoalbuminemic critically ill children are high but were not upregulated through nutrient supply, and in septic adolescents are unaffected by insulin.
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Mak RH, Ikizler AT, Kovesdy CP, Raj DS, Stenvinkel P, Kalantar-Zadeh K. Wasting in chronic kidney disease. J Cachexia Sarcopenia Muscle 2011; 2:9-25. [PMID: 21475675 PMCID: PMC3063874 DOI: 10.1007/s13539-011-0019-5] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 01/25/2011] [Indexed: 11/17/2022] Open
Abstract
Wasting/cachexia is prevalent among patients with chronic kidney disease (CKD). It is to be distinguished from malnutrition, which is defined as the consequence of insufficient food intake or an improper diet. Malnutrition is characterized by hunger, which is an adaptive response, whereas anorexia is prevalent in patients with wasting/cachexia. Energy expenditure decreases as a protective mechanism in malnutrition whereas it remains inappropriately high in cachexia/wasting. In malnutrition, fat mass is preferentially lost and lean body mass and muscle mass is preserved. In cachexia/wasting, muscle is wasted and fat is relatively underutilized. Restoring adequate food intake or altering the composition of the diet reverses malnutrition. Nutrition supplementation does not totally reverse cachexia/wasting. The diagnostic criteria of cachexia/protein-energy wasting in CKD are considered. The association of wasting surrogates, such as serum albumin and prealbumin, with mortality is strong making them robust outcome predictors. At the patient level, longevity has consistently been observed in patients with CKD who have more muscle and/or fat, who report better appetite and who eat more. Although inadequate nutritional intake may contribute to wasting or cachexia, recent evidence indicates that other factors, including systemic inflammation, perturbations of appetite-controlling hormones from reduced renal clearance, aberrant neuropeptide signaling, insulin and insulin-like growth factor resistance, and metabolic acidosis, may be important in the pathogenesis of CKD-associated wasting. A number of novel therapeutic approaches, such as ghrelin agonists and melanocortin receptor antagonists are currently at the experimental level and await confirmation by randomized controlled clinical trials in patients with CKD-associated cachexia/wasting syndrome.
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Affiliation(s)
- Robert H. Mak
- Division of Pediatric Nephrology, University of California San Diego, 9500 Gilman Drive. MC 0634, La Jolla, CA 92093-0634 USA
- Rady Children’s Hospital of San Diego, San Diego, CA 92093-0634 USA
| | - Alp T. Ikizler
- Division of Nephrology, Vanderbilt University Med. Center, Nashville, TN USA
| | - Csaba P. Kovesdy
- Division of Nephrology, University of Virginia, Charlottesville, VA USA
- Division of Nephrology, Salem Veterans Affairs Medical Center, Salem, VA USA
| | - Dominic S. Raj
- Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC USA
| | - Peter Stenvinkel
- Division of Renal Medicine, Karolinska University Hospital at Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Kamyar Kalantar-Zadeh
- Harold Simmons Center for Kidney Disease Research and Epidemiology, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA USA
- Division of Nephrology and Hypertension, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA USA
- David Geffen School of Medicine at UCLA, Los Angeles, CA USA
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Adaptations of hepatic amino acid uptake and net utilisation contributes to nitrogen economy or waste in lambs fed nitrogen- or energy-deficient diets. Animal 2011; 5:678-90. [DOI: 10.1017/s1751731110002302] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Savary-Auzeloux I, Kraft G, Bequette BJ, Papet I, Rémond D, Ortigues-Marty I. Dietary nitrogen-to-energy ratio alters amino acid partition in the whole body and among the splanchnic tissues of growing rams1. J Anim Sci 2010; 88:2122-31. [DOI: 10.2527/jas.2009-2062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Tessari P, Cosma A, Vettore M, Millioni R, Puricelli L, Cogo P, Cecchet D, Carnielli V, Kiwanuka E. Fibrinogen kinetics and protein turnover in obese non-diabetic males: effects of insulin. Diabetes Metab Res Rev 2010; 26:50-8. [PMID: 19943326 DOI: 10.1002/dmrr.1055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Although hyperfibrinogenemia and insulin resistance are common in obesity and diabetes mellitus, the impact of obesity per se on fibrinogen turnover and the insulin effects on fibrinogen and protein kinetics is unknown. METHODS We measured fibrinogen and albumin fractional (FSR) and absolute (ASR) synthesis rates, as well as protein turnover, in non-diabetic, obese and in control male subjects both before and following an euglycemic, euaminoacidemic, hyperinsulinemic clamp, using L-[(2)H(3)]-Leucine isotope infusion. RESULTS In the obese, basal fibrinogen concentrations was approximately 25% greater (p < 0.035), and fibrinogen pool approximately 45% greater (p < 0.005), than in controls. Both FSR and ASR of fibrinogen were similar to control values. With hyperinsulinemia, although fibrinogen FSR and ASR were not significantly modified with respect to baseline in either group, fibrinogen ASR resulted to be approximately 50% greater in the obese than in controls (p < 0.015). Hyperinsulinemia equally stimulated albumin synthesis and suppressed leucine appearance from endogenous proteolysis in both groups. Amino acid clearance was also similar. In the obese, the insulin-mediated glucose disposal was approximately 50% lower (p < 0.03) than in controls, and it was inversely correlated with fibrinogen ASR during the clamp in both groups (r = - 0.58). CONCLUSIONS In obese, non-diabetic males, post absorptive fibrinogen production is normal. Whole-body amino acid disposal, basal and insulin-responsive protein degradation, and albumin synthesis are also normal. However, the greater fibrinogen ASR in the obese with hyperinsulinemia, and the inverse relationship between insulin sensitivity and clamp fibrinogen production, suggest a role for hyperinsulinemia and/or insulin resistance on fibrinogen production in obesity.
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Affiliation(s)
- P Tessari
- Department of Clinical and Experimental Medicine, Chair of Metabolism, Policlinico Universitario, via Giustiniani 2, Padua, Italy.
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Tan SY, Batterham M, Tapsell L. Energy expenditure does not differ, but protein oxidation rates appear lower in meals containing predominantly meat versus soy sources of protein. Obes Facts 2010; 3:101-4. [PMID: 20484942 PMCID: PMC6452156 DOI: 10.1159/000290061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND High protein meals produce 3 relevant effects in weight management: i) higher thermogenic cost, ii) enhanced fat oxidation, and iii) greater satiation. Pork has been reported to be more thermogenic than soy, suggesting meat protein may be superior to plant protein in a high-protein weight loss diet context. In this study, we aimed to compare the effects of high-protein meals using meat, dairy, and soy sources respectively. METHODS This crossover feeding trial measured energy expenditure, substrate oxidation, and satiety levels of 12 adults during 8-hour stays in a whole-room calorimeter. The 3 isoenergetic high-protein test meals (30% protein, 40% carbohydrate, 30% fat) contained predominantly meat, dairy, and soy protein. RESULTS There was no significant difference between meals for effects on energy expenditure (p = 0.987), carbohydrate oxidation (p = 0.951), and fat oxidation (p = 0.997). Protein oxidation was significantly lower in meals with predominantly meat compared to soy sources (p = 0.012). There was no significant difference between meals for reported satiety levels (p = 0.296). CONCLUSION High-protein meals may be argued as beneficial for weight loss. Animal protein does not appear to offer superior energy expenditure effects, but there may be protein-sparing effects with meat, which may be beneficial in terms of retaining lean body mass.
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Affiliation(s)
- Sze-Yen Tan
- Smart Foods Centre, University of Wollongong, Wollongong, NSW, Australia.
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Abstract
The liver plays a unique role in nutrient homeostasis. Its anatomical location makes it ideally suited to control the systemic supply of absorbed nutrients, and it is the primary organ that can both consume and produce substantial amounts of glucose. Moreover, it is the site of a substantial fraction (about 25 %) of the body's protein synthesis, and the liver and other organs of the splanchnic bed play an important role in sparing dietary N by storing ingested amino acids. This hepatic anabolism is under the control of hormonal and nutritional changes that occur during food intake. In particular, the route of nutrient delivery, i.e. oral (or intraportal) v. peripheral venous, appears to impact upon the disposition of the macronutrients and also to affect both hepatic and whole-body nutrient metabolism. Intraportal glucose delivery significantly enhances net hepatic glucose uptake, compared with glucose infusion via a peripheral vein. On the other hand, concomitant intraportal infusion of both glucose and gluconeogenic amino acids significantly decreases net hepatic glucose uptake, compared with infusion of the same mass of glucose by itself. Delivery of amino acids via the portal vein may enhance their hepatic uptake, however. Elevation of circulating lipids under postprandial conditions appears to impair both hepatic and whole-body glucose disposal. Thus, the liver's role in nutrient disposal and metabolism is highly responsive to the route of nutrient delivery, and this is an important consideration in planning nutrition support and optimising anabolism in vulnerable patients.
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Fouillet H, Juillet B, Gaudichon C, Mariotti F, Tomé D, Bos C. Absorption kinetics are a key factor regulating postprandial protein metabolism in response to qualitative and quantitative variations in protein intake. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1691-705. [PMID: 19812354 DOI: 10.1152/ajpregu.00281.2009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated that increasing the habitual protein intake widened the gap in nutritional quality between proteins through mechanisms that are not yet fully understood. We hypothesized that the differences in gastrointestinal kinetics between dietary proteins were an important factor affecting their differential response to an increased protein intake. To test this hypothesis, we built a 13-compartment model providing integrative insight into the sequential dynamics of meal nitrogen (Nm) absorption, splanchnic uptake, and metabolism, and subsequent peripheral transfer and deposition. The model was developed from data on postprandial Nm kinetics in certain accessible pools, obtained from subjects having ingested a (15)N-labeled milk or soy protein meal, after adaptation to normal (NP) or high (HP) protein diets. The faster absorption of Nm after soy vs. milk caused its earlier and stronger splanchnic delivery, which favored its local catabolic utilization (up to +30%) and limited its peripheral accretion (down to -20%). Nm absorption was also accelerated after HP vs. NP adaptation, and this kinetic effect accounted for most of the HP-induced increase (up to +20%) in splanchnic Nm catabolic use, and the decrease (down to -25%) in peripheral Nm anabolic utilization. The HP-induced acceleration in Nm absorption was more pronounced with soy than with milk, as were the HP effects on Nm regional metabolism. Our integrative approach identified Nm absorption kinetics, which exert a direct and lasting impact on Nm splanchnic catabolic use and peripheral delivery, as being critical in adaptation to both qualitative and quantitative changes in protein intake.
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Affiliation(s)
- Hélène Fouillet
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France.
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Deglaire A, Fromentin C, Fouillet H, Airinei G, Gaudichon C, Boutry C, Benamouzig R, Moughan PJ, Tomé D, Bos C. Hydrolyzed dietary casein as compared with the intact protein reduces postprandial peripheral, but not whole-body, uptake of nitrogen in humans. Am J Clin Nutr 2009; 90:1011-22. [PMID: 19692493 DOI: 10.3945/ajcn.2009.27548] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Compared with slow proteins, fast proteins are more completely extracted in the splanchnic bed but contribute less to peripheral protein accretion; however, the independent influence of absorption kinetics and the amino acid (AA) pattern of dietary protein on AA anabolism in individual tissues remains unknown. OBJECTIVE We aimed to compare the postprandial regional utilization of proteins with similar AA profiles but different absorption kinetics by coupling clinical experiments with compartmental modeling. DESIGN Experimental data pertaining to the intestine, blood, and urine for dietary nitrogen kinetics after a 15N-labeled intact (IC) or hydrolyzed (HC) casein meal were obtained in parallel groups of healthy adults (n = 21) and were analyzed by using a 13-compartment model to predict the cascade of dietary nitrogen absorption and regional metabolism. RESULTS IC and HC elicited a similar whole-body postprandial retention of dietary nitrogen, but HC was associated with a faster rate of absorption than was IC, resulting in earlier and stronger hyperaminoacidemia and hyperinsulinemia. An enhancement of both catabolic (26%) and anabolic (37%) utilization of dietary nitrogen occurred in the splanchnic bed at the expense of its further peripheral availability, which reached 18% and 11% of ingested nitrogen 8 h after the IC and HC meals, respectively. CONCLUSIONS The form of delivery of dietary AAs constituted an independent factor of modulation of their postprandial regional metabolism, with a fast supply favoring the splanchnic dietary nitrogen uptake over its peripheral anabolic use. These results question a possible effect of ingestion of protein hydrolysates on tissue nitrogen metabolism and accretion. This trial was registered at clinicaltrials.gov as NCT00873951.
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Affiliation(s)
- Amélie Deglaire
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
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Lysosomal and proteasome-dependent proteolysis are differentially regulated by insulin and/or amino acids following feeding in young, mature and old rats. J Nutr Biochem 2009; 20:570-6. [DOI: 10.1016/j.jnutbio.2008.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 05/21/2008] [Accepted: 05/22/2008] [Indexed: 11/18/2022]
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Tjiong HL, Swart R, van den Berg JW, Fieren MW. Amino Acid-Based Peritoneal Dialysis Solutions for Malnutrition: New Perspectives. Perit Dial Int 2009. [DOI: 10.1177/089686080902900404] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Protein and energy malnutrition is frequently found in patients on maintenance dialysis and is associated with an increased risk of death. Among a variety of factors involved in the development of protein and energy malnutrition, such as acidosis, insulin resistance, inflammation, and dialysate protein losses, insufficient intake of proteins and energy as a result of anorexia plays a prominent role. Amino acid (AA)-based peritoneal dialysis (PD) solutions can induce an anabolic response in malnourished patients on continuous ambulatory PD if enough calories are ingested simultaneously. Poor appetite, however, may impede the intake of sufficient calories. Peritoneal dialysis solutions containing a mixture of AAs and glucose in a proper ratio can serve as a source of proteins and calories. Such a dialysis solution can be used in fasting patients on nocturnal automated PD as part of a regular dialysis schedule. Using a sophisticated technique involving stable isotopes, this dialysis mixture has been found to induce acute anabolic changes in whole body protein metabolism. Such a metabolic response is similar to that induced by food. Intraperitoneal AAs, in common with ingested proteins, can induce generation of hydrogen ions and urea through oxidation of specific AAs. Supplying AAs together with calories could bring about utilization of AAs for the synthesis of proteins rather than the oxidation of AAs, thereby limiting production of acid and urea. Using dialysis solutions with a buffer concentration of 40 mmol/L further contributes to maintaining acid–base homeostasis. We advocate consideration of usage of AA/glucose dialysate when PD patients cannot comply with dietary requirements. To evaluate the long-term effects of this approach on morbidity and mortality, clinical trials with large groups of patients are needed.
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Affiliation(s)
- Hoey Lan Tjiong
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Roel Swart
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Marien W. Fieren
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
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Abstract
Aging is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk of developing chronic metabolic disease. The age-related loss of skeletal muscle mass is attributed to a disruption in the regulation of skeletal muscle protein turnover, resulting in an imbalance between muscle protein synthesis and degradation. As basal (fasting) muscle protein synthesis rates do not seem to differ substantially between the young and elderly, many research groups have started to focus on the muscle protein synthetic response to the main anabolic stimuli, i.e., food intake and physical activity. Recent studies suggest that the muscle protein synthetic response to food intake is blunted in the elderly. The latter is now believed to represent a key factor responsible for the age-related decline in skeletal muscle mass. Physical activity and/or exercise stimulate postexercise muscle protein accretion in both the young and elderly. However, the latter largely depends on the timed administration of amino acids and/or protein before, during, and/or after exercise. Prolonged resistance type exercise training represents an effective therapeutic strategy to augment skeletal muscle mass and improve functional performance in the elderly. The latter shows that the ability of the muscle protein synthetic machinery to respond to anabolic stimuli is preserved up to very old age. Research is warranted to elucidate the interaction between nutrition, exercise, and the skeletal muscle adaptive response. The latter is needed to define more effective strategies that will maximize the therapeutic benefits of lifestyle intervention in the elderly.
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Affiliation(s)
- René Koopman
- Department of Human Movement Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands
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Abstract
PURPOSE OF REVIEW To draw attention to recent work on the role of protein and the amount of protein needed with each meal to preserve skeletal muscle mass in ageing. RECENT FINDINGS Ageing does not inevitably reduce the anabolic response to a high-quality protein meal. Ingestion of approximately 25-30 g of protein per meal maximally stimulates muscle protein synthesis in both young and older individuals. However, muscle protein synthesis is blunted in elderly when protein and carbohydrate are coingested or when the quantity of protein is less than approximately 20 g per meal. Supplementing regular mixed-nutrient meals with leucine may also enhance the muscle protein synthetic response in elders. SUMMARY On the basis of recent work, we propose a novel and specific dietary approach to prevent or slow down muscle loss with ageing. Rather than recommending a large, global increase in the recommended dietary allowance (RDA) for protein for all elderly individuals, clinicians should stress the importance of ingesting a sufficient amount of protein with each meal. To maximize muscle protein synthesis while being cognizant of total energy intake, we propose a dietary plan that includes 25-30 g of high quality protein per meal.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Physical Therapy, Division of Rehabilitation Sciences. The University of Texas Medical Branch. 301 University Blvd. Galveston, Texas 77555-1144, USA.
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Effects of infliximab and parenteral nutrition on albumin and fibrinogen synthesis rates in pediatric Crohn disease. J Pediatr Gastroenterol Nutr 2008; 47:579-84. [PMID: 18979581 DOI: 10.1097/mpg.0b013e3181653a89] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Tumor necrosis factor-alpha (TNF-alpha) may play a significant role in growth disturbance in pediatric Crohn disease. The aim of this study was to determine the effects of anti-TNF-alpha therapy on albumin and fibrinogen synthesis during both fasting and parenteral nutrition infusion in pediatric patients with active Crohn disease. PATIENTS AND METHODS Children with active Crohn disease scheduled for their initial dose of infliximab underwent assessment immediately before and 2 weeks following infliximab infusion. Using the stable isotope [d5] phenylalanine, rates of fractional and absolute albumin and fibrinogen synthesis were calculated. Measurements were made in both the fasting and parenterally fed states. RESULTS Fifteen children (mean age 14.9 +/- 0.3) completed the study. The mean serum albumin changed from 3.59 +/- 0.08 to 3.66 +/- 0.04 g/dL, and the mean fibrinogen level decreased from 230 +/- 17 to 187 +/- 8 mg/dL (P < 0.05) following infliximab therapy. During fasting, there were no changes in albumin and fibrinogen synthesis rates following infliximab. During parenteral nutrition infusion, the fractional albumin synthesis rate changed from 11.8% to 15.1%/day (P = 0.06), and the absolute albumin synthesis rate increased from 192 to 248 mg x kg(-1) x day(-1) (P < 0.05), whereas no changes in fibrinogen synthesis rates were observed. Synthesis rates of albumin and fibrinogen were increased during parenteral nutrition infusion compared with the fasting state. CONCLUSIONS Following infliximab therapy, during parenteral nutrition infusion, albumin synthesis increased significantly. Conversely, serum fibrinogen levels decreased following infliximab therapy in the absence of significant change in synthesis rates.
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Dardevet D, Kimball SR, Jefferson LS, Cherrington AD, Rémond D, DiCostanzo CA, Moore MC. Portal infusion of amino acids is more efficient than peripheral infusion in stimulating liver protein synthesis at the same hepatic amino acid load in dogs. Am J Clin Nutr 2008; 88:986-96. [PMID: 18842785 PMCID: PMC2750082 DOI: 10.1093/ajcn/88.4.986] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hepatic glucose uptake is enhanced by the portal delivery of glucose, which creates a negative arterioportal substrate gradient. Hepatic amino acid (AA) utilization may be regulated by the same phenomenon, but this has not been proven. OBJECTIVE We aimed to assess hepatic AA balance and protein synthesis with or without a negative arterioportal AA gradient. DESIGN Somatostatin was infused intravenously, and insulin and glucagon were replaced intraportally at 4- and 3-fold basal rates, respectively, in 3 groups (n = 9 each) of conscious dogs with catheters for hepatic balance measurement. Arterial glucose concentrations were clamped at 9 mmol/L. An AA mixture was infused intravenously to maintain basal concentrations (EuAA), intraportally to mimic the postmeal AA increase (PoAA), or intravenously (PeAA) to match the hepatic AA load in PoAA. Protein synthesis was assessed with a primed, continuous [(14)C]leucine infusion. RESULTS Net hepatic glucose uptake in the PoAA condition was < or =50% of that in the EuAA and PeAA conditions (P < 0.05). In the PoAA and PeAA conditions, hepatic intracellular leucine concentrations were 2- to 2.5-fold those in the EuAA condition (P < 0.05); net hepatic leucine uptake and [(14)C]leucine utilization were approximately 2-fold greater (P < 0.05) and albumin synthesis was 30% greater (P < 0.05) in the PoAA condition than in the EuAA and PeAA conditions. Phosphorylation of ribosomal protein S6 [downstream of the mammalian target of Rapamycin complex 1 (mTORC1)] was significantly higher in the PoAA, but not PeAA, condition than in the EuAA condition. CONCLUSIONS Portal, but not peripheral, AA delivery significantly enhanced hepatic protein synthesis under conditions in which AAs, glucose, insulin, and glucagon did not differ at the liver, an effect apparently mediated by mTORC1 signaling.
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Affiliation(s)
- Dominique Dardevet
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.
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Paddon-Jones D, Short KR, Campbell WW, Volpi E, Wolfe RR. Role of dietary protein in the sarcopenia of aging. Am J Clin Nutr 2008; 87:1562S-1566S. [PMID: 18469288 DOI: 10.1093/ajcn/87.5.1562s] [Citation(s) in RCA: 246] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Sarcopenia is a complex, multifactorial process facilitated by a combination of factors including the adoption of a more sedentary lifestyle and a less than optimal diet. Increasing evidence points to a blunted anabolic response after a mixed nutrient meal as a likely explanation for chronic age-related muscle loss. There is currently insufficient longer-term research with defined health outcomes to specify an optimal value for protein ingestion in elderly individuals. However, there is general agreement that moderately increasing daily protein intake beyond 0.8 g x kg(-1) x d(-1) may enhance muscle protein anabolism and provide a means of reducing the progressive loss of muscle mass with age. The beneficial effects of resistance exercise in aging populations are unequivocal. However, research has not identified a synergistic effect of protein supplementation and resistance exercise in aging populations. There is little evidence that links high protein intakes to increased risk for impaired kidney function in healthy individuals. However, renal function decreases with age, and high protein intake is contraindicated in individuals with renal disease. Assessment of renal function is recommended for older individuals before they adopt a higher-protein diet.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Physical Therapy, The University of Texas Medical Branch, Galveston, TX 77555-1144, USA.
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van den Akker CHP, te Braake FWJ, Schierbeek H, Rietveld T, Wattimena DJL, Bunt JEH, van Goudoever JB. Albumin synthesis in premature neonates is stimulated by parenterally administered amino acids during the first days of life. Am J Clin Nutr 2007; 86:1003-8. [PMID: 17921377 DOI: 10.1093/ajcn/86.4.1003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We recently showed that parenteral administration of amino acids to premature infants immediately after birth is safe and results in a positive nitrogen balance and increased whole-body protein synthesis. However, we did not determine organ-specific effects; albumin, produced by the liver, is an important protein, but its concentration is often low in premature neonates during the first few days after birth. OBJECTIVE The objective of the study was to test the hypothesis that the fractional and absolute albumin synthesis rates would increase with the administration of amino acids after birth, even at low nonprotein energy intake. DESIGN Premature infants (<1500 g birth weight), who were on ventilation, received from birth onward either glucose only (control group, n = 7) or glucose and 2.4 g amino acid kg(-1) d(-1) (intervention group, n = 8). On postnatal day 2, all infants received a primed continuous infusion of [1-(13)C]leucine, and mass spectrometry techniques were used to determine the incorporation of the leucine into albumin. Results are expressed as medians and 25th and 75th percentiles. RESULTS Albumin fractional synthesis rates in the intervention group were significantly higher than those in the control group [22.9% (17.6-28.0%)/d and 12.6% (11.0-19.4%)/d, respectively; P = 0.029]. Likewise, the albumin absolute synthesis rates in the intervention group were significantly higher than those in the control group [228 (187-289) mg kg(-1) d(-1) and 168 (118-203) mg kg(-1) d(-1), respectively; P = 0.030]. CONCLUSION Amino acid administration increases albumin synthesis rates in premature neonates even at a low energy intake.
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Affiliation(s)
- Chris H P van den Akker
- Division of Neonatology, Department of Pediatrics, Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, Netherlands
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Tjiong HL, Fieren MW, Rietveld T, Wattimena JL, Schierbeek H, Huijmans JGM, Hop WC, Swart GR, van den Berg JW. Albumin and whole-body protein synthesis respond differently to intraperitoneal and oral amino acids. Kidney Int 2007; 72:364-9. [PMID: 17554255 DOI: 10.1038/sj.ki.5002364] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Patients with peritoneal dialysis are at risk for malnutrition and hypoalbuminemia, which are indicators of poor outcome. Recently, it was shown that dialysis solutions containing amino acids (AAs) and glucose improve protein anabolism in peritoneal dialysis patients. We determined if the same solutions could increase the fractional synthesis rate of albumin along with whole-body protein synthesis. Changes in the fractional albumin synthetic rate reflect acute change in hepatic albumin synthesis. A random-order cross-over study compared the effects of Nutrineal (AA source) plus Physioneal (glucose) dialysate with Physioneal alone dialysate. Eight patients in the overnight fasting state were compared to 12 patients in the daytime-fed state. Fractional albumin synthetic rate and whole-body protein synthesis were determined simultaneously using a primed-continuous infusion of L-[1-(13)C]-leucine. Fractional albumin synthesis on AAs plus glucose dialysis did not differ significantly from that on glucose alone in the fasting or the fed state. Protein intake by itself (fed versus fasting) failed to induce a significant increase in the fractional synthetic rate of albumin. Conversely, the oral protein brought about a significant stimulation of whole-body protein synthesis. Our findings show that the supply of AAs has different effects on whole-body protein synthesis and the fractional synthetic rate of albumin.
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Affiliation(s)
- H L Tjiong
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
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Caso G, Feiner J, Mileva I, Bryan LJ, Kelly P, Autio K, Gelato MC, McNurlan MA. Response of albumin synthesis to oral nutrients in young and elderly subjects. Am J Clin Nutr 2007; 85:446-51. [PMID: 17284742 DOI: 10.1093/ajcn/85.2.446] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The synthesis of albumin after oral ingestion of nutrients provides a means of storing amino acids, which can be made available during periods of fasting. OBJECTIVE This study was undertaken to see whether the response of albumin synthesis to the oral intake of nutrients is compromised in elderly subjects. DESIGN Albumin synthesis was determined from the incorporation of 43 mg l-[(2)H(5)]phenylalanine/kg body wt. Eight elderly subjects (aged >60 y) and 8 young subjects (aged 21-35 y) were studied on 3 separate occasions: after the intake of water, a liquid meal (with 15% of energy from protein, 30% of energy from fat, and 55% of energy from carbohydrate), or an isonitrogenous but not isocaloric meal containing only protein. RESULTS Mean (+/-SEM) albumin synthesis, expressed as an absolute rate (ie, the amount of albumin synthesized per day), was significantly lower in elderly subjects (108 +/- 7 mg . kg body wt(-1) . d(-1)) than in young subjects (141 +/- 7 mg . kg body wt(-1) . d(-1)). In response to the complete meal, albumin synthesis was significantly increased in both the elderly (144 +/- 7 mgkg body wt(-1) . d(-1)) and the young (187 +/- 11 mg . kg body wt(-1) . d(-1)) subjects. The protein component of the meal was sufficient to stimulate albumin synthesis in both the elderly (147 +/- 14 mg . kg body wt(-1) . d(-1)) and the young (182 +/- 6 mg . kg body wt(-1) . d(-1)) subjects. CONCLUSIONS Elderly subjects have lower rates of albumin synthesis than do young subjects during fasting, but they stimulate albumin synthesis proportionately in response to the oral ingestion of protein. The intakes of additional fat and carbohydrate do not stimulate albumin synthesis further.
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Affiliation(s)
- Giuseppe Caso
- Departments of Surgery, Stony Brook University, Stony Brook, NY
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Tjiong HL, Rietveld T, Wattimena JL, van den Berg JW, Kahriman D, van der Steen J, Hop WC, Swart R, Fieren MW. Peritoneal dialysis with solutions containing amino acids plus glucose promotes protein synthesis during oral feeding. Clin J Am Soc Nephrol 2006; 2:74-80. [PMID: 17699390 DOI: 10.2215/cjn.01370406] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Inadequate food intake plays an important role in the development of malnutrition. Recently, an increased rate of protein anabolism was shown in fasting state in patients who were on automated peritoneal dialysis with combined amino acids (AA) and glucose (G) dialysate serving as a source of both proteins and calories. This study investigated the effects of such a dialysis procedure in the daytime in the fed state in patients who were on continuous ambulatory peritoneal dialysis (CAPD). A crossover study was performed in 12 CAPD patients to compare, at 7-d intervals, a mixture of AA (Nutrineal 1.1%) plus G (Physioneal l.36 to 3.86%) versus G only as control dialysate. Whole-body protein turnover was studied by primed constant intravenous infusion of (13)C-leucine during the 9-h dialysis. For meeting steady-state conditions during whole-body protein turnover, frequent exchanges with a mixture of AA plus G were done using an automated cycler. Fed-state conditions were created by identical liquid hourly meals. Using AA plus G dialysate, as compared with the control, rates of protein synthesis increased significantly (2.02 +/- 0.08 versus 1.94 +/- 0.07 mumol leucine/kg per min [mean +/- SEM]; P = 0.039). Rates of protein breakdown and net protein balance did not differ significantly between AA plus G and G. In conclusion, dialysate that contains AA plus G also improves protein synthesis in fed CAPD patients. The use of such a mixture may contribute to long-term improvement of the nutritional status in malnourished CAPD patients with deficient food intake.
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Affiliation(s)
- Hoey Lan Tjiong
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands.
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Fujita S, Rasmussen BB, Cadenas JG, Grady JJ, Volpi E. Effect of insulin on human skeletal muscle protein synthesis is modulated by insulin-induced changes in muscle blood flow and amino acid availability. Am J Physiol Endocrinol Metab 2006; 291:E745-54. [PMID: 16705054 PMCID: PMC2804964 DOI: 10.1152/ajpendo.00271.2005] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Insulin promotes muscle anabolism, but it is still unclear whether it stimulates muscle protein synthesis in humans. We hypothesized that insulin can increase muscle protein synthesis only if it increases muscle amino acid availability. We measured muscle protein and amino acid metabolism using stable-isotope methodologies in 19 young healthy subjects at baseline and during insulin infusion in one leg at low (LD, 0.05), intermediate (ID, 0.15), or high (HD, 0.30 mUxmin(-1)x100 ml(-1)) doses. Insulin was infused locally to induce muscle hyperinsulinemia within the physiological range while minimizing the systemic effects. Protein and amino acid kinetics across the leg were assessed using stable isotopes and muscle biopsies. The LD did not affect phenylalanine delivery to the muscle (-9 +/- 18% change over baseline), muscle protein synthesis (16 +/- 26%), breakdown, or net balance. The ID increased (P < 0.05) phenylalanine delivery (+63 +/- 38%), muscle protein synthesis (+157 +/- 54%), and net protein balance, with no change in breakdown. The HD did not change phenylalanine delivery (+12 +/- 11%) or muscle protein synthesis (+9 +/- 19%), and reduced muscle protein breakdown (-17 +/- 15%), thus improving net muscle protein balance but to a lesser degree than the ID. Changes in muscle protein synthesis were strongly associated with changes in muscle blood flow and phenylalanine delivery and availability. In conclusion, physiological hyperinsulinemia promotes muscle protein synthesis as long as it concomitantly increases muscle blood flow, amino acid delivery and availability.
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Affiliation(s)
- Satoshi Fujita
- Department of Medicine, University of Southern California, Los Angeles, California, USA
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Tessari P, Kiwanuka E, Barazzoni R, Vettore M, Zanetti M. Diabetic nephropathy is associated with increased albumin and fibrinogen production in patients with type 2 diabetes. Diabetologia 2006; 49:1955-61. [PMID: 16703327 DOI: 10.1007/s00125-006-0288-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Accepted: 03/29/2006] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS Hyperfibrinogenaemia and albuminuria are cardiovascular risk factors, often coexisting in diabetic and non-diabetic people. Albuminuria in turn is associated with a compensatory albumin overproduction in non-diabetic patients. It is not known whether the presence of albuminuria in patients with type 2 diabetes mellitus is associated with greater albumin and fibrinogen production rates than in normoalbuminuric patients. SUBJECTS, MATERIALS, AND METHODS: Using leucine isotope methods, we measured fractional and absolute synthesis rates (FSR, ASR) of albumin and fibrinogen in post-absorptive type 2 diabetic patients with either normal (n=11) or increased (n=10) urinary albumin excretion. RESULTS In albuminuric patients, albumin FSR (16.2+/-1.5%/day) and ASR (20.5+/-1.9 g/day) were greater (p<0.02 and p<0.05, respectively) than in normoalbuminuric patients (FSR=11.5+/-1.1%/day; ASR=15.7+/-1.2 g/day). Fibrinogen FSR was similar between patients with normal and increased albumin excretion, but concentration, the circulating pool and ASR of fibrinogen were 40 to 50% greater (p<0.035) in patients with albuminuria. Albuminuria was positively correlated with albumin ASR, with fibrinogen concentration, the fibrinogen pool and ASR, whereas albumin synthesis was inversely correlated with calculated oncotic pressure. CONCLUSIONS/INTERPRETATION Synthesis of albumin and fibrinogen is upregulated in type 2 diabetic patients with increased urinary albumin excretion. Albuminuria is associated with enhanced fibrinogen and albumin synthesis.
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Affiliation(s)
- P Tessari
- Department of Clinical and Experimental Medicine, Metabolism Division, University of Padua, Padua, Italy.
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Yamaoka I, Doi M, Nakayama M, Ozeki A, Mochizuki S, Sugahara K, Yoshizawa F. Intravenous administration of amino acids during anesthesia stimulates muscle protein synthesis and heat accumulation in the body. Am J Physiol Endocrinol Metab 2006; 290:E882-8. [PMID: 16352675 DOI: 10.1152/ajpendo.00333.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study was conducted to determine the contribution of muscle protein synthesis to the prevention of anesthesia-induced hypothermia by intravenous administration of an amino acid (AA) mixture. We examined the changes of intraperitoneal temperature (Tcore) and the rates of protein synthesis (K(s)) and the phosphorylation states of translation initiation regulators and their upstream signaling components in skeletal muscle in conscious (Nor) or propofol-anesthetized (Ane) rats after a 3-h intravenous administration of a balanced AA mixture or saline (Sal). Compared with Sal administration, the AA mixture administration markedly attenuated the decrease in Tcore in rats during anesthesia, whereas Tcore in the Nor-AA group became slightly elevated during treatment. Stimulation of muscle protein synthesis resulting from AA administration was observed in each case, although K(s) remained lower in the Ane-AA group than in the Nor-Sal group. AA administration during anesthesia significantly increased insulin concentrations to levels approximately 6-fold greater than in the Nor-AA group and enhanced phosphorylation of eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) and ribosomal protein S6 protein kinase relative to all other groups and treatments. The alterations in the Ane-AA group were accompanied by hyperphosphorylation of protein kinase B and the mammalian target of rapamycin (mTOR). These results suggest that administration of an AA mixture during anesthesia stimulates muscle protein synthesis via insulin-mTOR-dependent activation of translation initiation regulators caused by markedly elevated insulin and, thereby, facilitates thermal accumulation in the body.
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Affiliation(s)
- Ippei Yamaoka
- Division of Pharmacology, Drug Safety and Metabolism, Otsuka Pharmaceutical Factory, Naruto, Tokushima 772-8601, Japan.
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Balagopal P, Olney R, Darmaun D, Mougey E, Dokler M, Sieck G, Hammond D. Oxandrolone enhances skeletal muscle myosin synthesis and alters global gene expression profile in Duchenne muscular dystrophy. Am J Physiol Endocrinol Metab 2006; 290:E530-9. [PMID: 16263771 DOI: 10.1152/ajpendo.00412.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Earlier studies have shown that the progressive, unrelenting muscle loss associated with Duchenne muscular dystrophy (DMD) involves an imbalance between the rates of synthesis and degradation of muscle proteins. Although previous studies have suggested that oxandrolone may be beneficial in DMD, the mechanism of action of oxandrolone on muscle in DMD remains unclear. To address these issues, we combined stable isotope studies and gene expression analysis to measure the fractional synthesis rate of myosin heavy chain (MHC), the key muscle contractile protein, the transcript levels of the isoforms of MHC, and global gene expression profiles in four children with DMD before and after 3 mo of treatment with oxandrolone. Gastrocnemius muscle biopsies and blood samples were collected during the course of a primed 6-h continuous infusion of l-[U-(13)C]leucine on two separate occasions, before and after the 3-mo treatment with oxandrolone (0.1 mg.kg(-1).day(-1)). Gene expression analysis was done with microarrays and RT-qPCR. In response to the treatment, MHC synthesis rate increased 42%, and this rise was accounted for, at least in part, by an upregulation of the transcript for MHC8 (perinatal MHC). Gene expression data suggested a decrease in muscle regeneration as a consequence of oxandrolone therapy, presumably because of a decrease in muscle degeneration. These findings suggest that 1) oxandrolone has a powerful protein anabolic effect on a key contractile protein and 2) larger and longer-term studies are warranted to determine whether these changes translate into meaningful therapy for these patients.
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Tessari P, Kiwanuka E, Millioni R, Vettore M, Puricelli L, Zanetti M, Gucciardi A, Tosolini M, Cogo P, Carnielli V, Tiengo A, Barazzoni R. Albumin and fibrinogen synthesis and insulin effect in type 2 diabetic patients with normoalbuminuria. Diabetes Care 2006; 29:323-8. [PMID: 16443881 DOI: 10.2337/diacare.29.02.06.dc05-0226] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Insulin stimulates albumin synthesis but inhibits that of fibrinogen in both type 1 diabetic and healthy subjects. In type 2 diabetes, fibrinogen production is increased both in the postabsorptive state and in response to hyperinsulinemia. No data exist on the rate of albumin synthesis and its response to insulin in type 2 diabetes. RESEARCH DESIGN AND METHODS We measured fractional synthesis rates (FSRs) and absolute synthesis rates (ASRs) of both albumin and fibrinogen in postabsorptive normoalbuminuric type 2 diabetic patients at their spontaneous glucose levels (study A), as well as albumin FSR and ASR before and after a hyperinsulinemic-euglycemic euaminoacidemic clamp (study B), using leucine isotope methods. RESULTS In postabsorptive type 2 diabetes (study A), albumin FSR (11.2 +/- 0.9%/day) and albumin ASR (15.4 +/- 1.2 g/day) were not different from control values (albumin FSR: 9.4 +/- 0.7%/day; albumin ASR: 13.8 +/- 1.2 g/day, P > 0.1 for both). In contrast, in the type 2 diabetic subjects, both fibrinogen FSR (24.9 +/- 2.1%/day) and ASR (2.4 +/- 0.2 g/day) were greater (P < 0.025 and P < 0.007, respectively) compared with the control subjects (FSR: 18.6 +/- 1.51%/day; ASR: 1.6 +/- 0.2 g/day). Worse metabolic control in the type 2 diabetic patients was associated with hyperfibrinogenemia and increased leucine rate of appearance, whereas neither the (increased) fibrinogen ASR nor the (normal) albumin production was affected. In study B, after hyperinsulinemia (raised to approximately 860 nmol/l), albumin FSR and ASR increased by approximately 25% versus basal (P < 0.04) and to the same extent in both type 2 diabetic and control subjects. CONCLUSIONS In normoalbuminuric type 2 diabetic patients, postabsorptive albumin synthesis and its response to insulin were normal, whereas fibrinogen synthesis was increased, irrespective of metabolic control. Furthermore, in normoalbuminuric type 2 diabetic patients, a normal insulin sensitivity with respect to albumin production but a selective hepatic dysregulation of fibrinogen metabolism were present.
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Affiliation(s)
- Paolo Tessari
- Department of Clinical and Experimental Medicine, Chair of Metabolism, Policlinico Universitario, Via Giustiniani 2, 35128 Padova, Italy.
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Chevalier S, Marliss EB, Morais JA, Lamarche M, Gougeon R. Whole-body protein anabolic response is resistant to the action of insulin in obese women. Am J Clin Nutr 2005; 82:355-65. [PMID: 16087979 DOI: 10.1093/ajcn.82.2.355] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Obesity is associated with insulin resistance of glucose and lipid metabolism. OBJECTIVE We sought to determine the effects of obesity on the insulin sensitivity of protein metabolism. DESIGN Whole-body [(13)C]leucine and [(3)H]glucose kinetics were measured in 9 lean and 10 obese women in the postabsorptive state and during a hyperinsulinemic, euglycemic, isoaminoacidemic clamp. RESULTS In the postabsorptive state, the leucine endogenous rate of appearance (catabolism), normalized for fat-free mass, was 11% greater and the nonoxidative rate of disappearance (synthesis) was 8% greater in the obese than in the lean women, but net balance was 29% more negative (P < 0.05). Clamp amino acid and glucose infusion rates were significantly lower in the obese women than in the lean women (0.65 +/- 0.02 compared with 0.85 +/- 0.04 and 5.7 +/- 0.3 compared with 9.1 +/- 0.5 mg x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001 for both), and their rates correlated positively (r = 0.635, P = 0.005). During hyperinsulinemia, synthesis was stimulated less and net leucine balance was much lower in the obese women than in the lean women (-0.08 +/- 0.06 and 0.30 +/- 0.03 mumol x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001). The percentage change in net leucine balance correlated negatively with all adiposity indexes. Plasma free fatty acids were less suppressed and the respiratory quotient was lower in the obese women than in the lean women. CONCLUSION Obese women show a blunted protein anabolic response to hyperinsulinemia that is consistent with resistance to the action of insulin on protein concurrent with that on glucose and lipid metabolism.
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Affiliation(s)
- Stéphanie Chevalier
- McGill Nutrition and Food Science Centre, McGill University Health Centre-Royal Victoria Hospital, Montreal, Canada
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Engelen MPKJ, Rutten EPA, De Castro CLN, Wouters EFM, Schols AMWJ, Deutz NEP. Altered interorgan response to feeding in patients with chronic obstructive pulmonary disease. Am J Clin Nutr 2005; 82:366-72. [PMID: 16087980 DOI: 10.1093/ajcn.82.2.366] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Previously, we reported increased values for whole-body protein turnover in patients with chronic obstructive pulmonary disease (COPD) in the postabsorptive state. OBJECTIVE The objective was to investigate whether intake of a carbohydrate-protein meal influences whole-body protein turnover differently in COPD patients and control subjects. DESIGN Eight normal-weight patients with moderate COPD and 8 healthy control subjects were examined in the postabsorptive state and after 2 h of repeatedly ingesting a maltodextrin casein-based protein meal (0.02 g x kg body wt(-1) x 20 min(-1)). Combined simultaneous, continuous, intravenous infusion of L-[ring-2H5]-phenylalanine and L-[ring-2H2]-tyrosine tracer and oral repeated ingestion of 1-13C-phenylalanine were performed to measure whole-body protein synthesis (WbPS) and first-pass splanchnic extraction of phenylalanine. Endogenous rate of appearance of phenylalanine as the measure of whole-body protein breakdown (WbPB) and netWbPS was calculated as WbPS--WbPB. Arterialized venous blood was sampled for amino acid enrichment and concentration analyses. RESULTS Feeding induced an increase in WbPS and a reduction in WbPB. The reduction in WbPB was larger in the COPD group than in the control group (P < 0.05) and was related to the lower splanchnic extraction of phenylalanine in the patients. Consequently, netWbPS increased more after feeding in the COPD group than in the control group (P < 0.05). CONCLUSION Feeding induces more protein anabolism in normal-weight patients with moderate COPD than in healthy control subjects. This is probably because these COPD patients are characterized by an adaptive interorgan response to feeding to prevent or delay weight loss at this disease stage.
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Affiliation(s)
- Mariëlle P K J Engelen
- Department of Respiratory Medicine and Surgery, Maastricht University, Maastricht, Netherlands.
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