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Valizade Hasanloei MA, Rahimlou M, Shojaa H, Morshedzadeh N, Tavasolian R, Hashemi R. The effect of wheat germ-enriched enteral formula on clinical and anthropometric factors in mechanically ventilated patients admitted to the intensive care unit. Clin Nutr ESPEN 2021; 46:40-46. [PMID: 34857227 DOI: 10.1016/j.clnesp.2021.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Nutritional support is considered as an important therapeutic strategy among critically ill patients. To evaluate the effect of a wheat germ-enriched formula in patients admitted to the intensive care unit (ICU). METHODS This randomized controlled clinical trial study was conducted on 100 patients admitted to the ICU. Patients randomly received a wheat germ-enriched formula or a standard formula from the first day of admission until weaning from the ventilator. Then, the duration of mechanical ventilation, the length of ICU, hospital admission, body composition and mortality rate were compared between the two groups. RESULTS Based on the results, wheat germ-enriched formula caused a significant reduction in the length of mechanical ventilation (29.80 ± 21.99 days vs. 36.48 ± 8.78 days, P < 0.001), the ICU length of stay (32.92 ± 21.04 days vs. 37.70 ± 8.76, P < 0.001), and the SOFA score (4.60 ± 1.28 vs. 5.68 ± 1.25, P < 0.001) compared to the control group. However, the intervention group demonstrated a significant increase in the basal metabolic rate, mid upper arm circumference, skeletal muscle mass, body cell mass, and GCS score compared to the control group (P < 0.05). Finally, no significant difference was observed between the two groups in terms of the hospital length of stay, ICU mortality, and body fat percentage (P > 0.05). CONCLUSION In general, wheat germ enriched formula may exert beneficial effect on clinical and anthropomorphic variables in patients admitted to the ICU. TRIAL REGISTRATION The study was approved by the Ethics Committee of the Urmia University of Medical Sciences under number IR.umsu.rec.1396.88 and registered at the Iranian Registry of Clinical Trials Website as IRCT20171221037983N3.
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Affiliation(s)
- Mohammad Amin Valizade Hasanloei
- Clinical Research Development Unit, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, West Azerbaijan Province, Iran
| | - Mehran Rahimlou
- Department of Nutrition, Faculty of Medicine, Zanjan University of Medical Sciences, Iran
| | - Hamed Shojaa
- Clinical Research Development Unit, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, West Azerbaijan Province, Iran
| | - Nava Morshedzadeh
- Department of Nutrition, Kerman University of Medical Sciences, Kerman, Iran
| | - Ronia Tavasolian
- Varastegan Institute for Medical Sciences University of Medical Sciences, Urmia, Iran
| | - Reza Hashemi
- Clinical Research Development Unit, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, West Azerbaijan Province, Iran.
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Jameson TSO, Kilroe SP, Fulford J, Abdelrahman DR, Murton AJ, Dirks ML, Stephens FB, Wall BT. Muscle damaging eccentric exercise attenuates disuse-induced declines in daily myofibrillar protein synthesis and transiently prevents muscle atrophy in healthy men. Am J Physiol Endocrinol Metab 2021; 321:E674-E688. [PMID: 34632796 PMCID: PMC8791791 DOI: 10.1152/ajpendo.00294.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Short-term disuse leads to muscle loss driven by lowered daily myofibrillar protein synthesis (MyoPS). However, disuse commonly results from muscle damage, and its influence on muscle deconditioning during disuse is unknown. Twenty-one males [20 ± 1 yr, BMI = 24 ± 1 kg·m-2 (± SE)] underwent 7 days of unilateral leg immobilization immediately preceded by 300 bilateral, maximal, muscle-damaging eccentric quadriceps contractions (DAM; subjects n = 10) or no exercise (CON; subjects n = 11). Participants ingested deuterated water and underwent temporal bilateral thigh MRI scans and vastus lateralis muscle biopsies of immobilized (IMM) and nonimmobilized (N-IMM) legs. N-IMM quadriceps muscle volume remained unchanged throughout both groups. IMM quadriceps muscle volume declined after 2 days by 1.7 ± 0.5% in CON (P = 0.031; and by 1.3 ± 0.6% when corrected to N-IMM; P = 0.06) but did not change in DAM, and declined equivalently in CON [by 6.4 ± 1.1% (5.0 ± 1.6% when corrected to N-IMM)] and DAM [by 2.6 ± 1.8% (4.0 ± 1.9% when corrected to N-IMM)] after 7 days. Immobilization began to decrease MyoPS compared with N-IMM in both groups after 2 days (P = 0.109), albeit with higher MyoPS rates in DAM compared with CON (P = 0.035). Frank suppression of MyoPS was observed between days 2 and 7 in CON (IMM = 1.04 ± 0.12, N-IMM = 1.86 ± 0.10%·day-1; P = 0.002) but not DAM (IMM = 1.49 ± 0.29, N-IMM = 1.90 ± 0.30%·day-1; P > 0.05). Declines in MyoPS and quadriceps volume after 7 days correlated positively in CON (r2 = 0.403; P = 0.035) but negatively in DAM (r2 = 0.483; P = 0.037). Quadriceps strength declined following immobilization in both groups, but to a greater extent in DAM. Prior muscle-damaging eccentric exercise increases MyoPS and prevents loss of quadriceps muscle volume after 2 (but not 7) days of disuse.NEW & NOTEWORTHY We investigated the impact of prior muscle-damaging eccentric exercise on disuse-induced muscle deconditioning. Two and 7 days of muscle disuse per se lowered quadriceps muscle volume in association with lowered daily myofibrillar protein synthesis (MyoPS). Prior eccentric exercise prevented the decline in muscle volume after 2 days and attenuated the decline in MyoPS after 2 and 7 days. These data indicate eccentric exercise increases MyoPS and transiently prevents quadriceps muscle atrophy during muscle disuse.
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Affiliation(s)
- Tom S O Jameson
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Sean P Kilroe
- Department of Nutrition and Metabolism, Center for Recovery, Physical Activity and Nutrition, University of Texas Medical Branch, Galveston, Texas
| | - Jonathan Fulford
- Peninsula NIHR Clinical Research Facility, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Doaa R Abdelrahman
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas
| | - Andrew J Murton
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas
- Sealy Center of Aging, University of Texas Medical Branch, Galveston, Texas
| | - Marlou L Dirks
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Francis B Stephens
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Benjamin T Wall
- Nutritional Physiology Group, Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
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Lamon S, Morabito A, Arentson-Lantz E, Knowles O, Vincent GE, Condo D, Alexander SE, Garnham A, Paddon-Jones D, Aisbett B. The effect of acute sleep deprivation on skeletal muscle protein synthesis and the hormonal environment. Physiol Rep 2021; 9:e14660. [PMID: 33400856 PMCID: PMC7785053 DOI: 10.14814/phy2.14660] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 11/08/2020] [Indexed: 12/18/2022] Open
Abstract
Chronic sleep loss is a potent catabolic stressor, increasing the risk of metabolic dysfunction and loss of muscle mass and function. To provide mechanistic insight into these clinical outcomes, we sought to determine if acute sleep deprivation blunts skeletal muscle protein synthesis and promotes a catabolic environment. Healthy young adults (N = 13; seven male, six female) were subjected to one night of total sleep deprivation (DEP) and normal sleep (CON) in a randomized cross‐over design. Anabolic and catabolic hormonal profiles were assessed across the following day. Postprandial muscle protein fractional synthesis rate (FSR) was assessed between 13:00 and 15:00 and gene markers of muscle protein degradation were assessed at 13:00. Acute sleep deprivation reduced muscle protein synthesis by 18% (CON: 0.072 ± 0.015% vs. DEP: 0.059 ± 0.014%·h‐1, p = .040). In addition, sleep deprivation increased plasma cortisol by 21% (p = .030) and decreased plasma testosterone by 24% (p = .029). No difference was found in the markers of protein degradation. A single night of total sleep deprivation is sufficient to induce anabolic resistance and a procatabolic environment. These acute changes may represent mechanistic precursors driving the metabolic dysfunction and body composition changes associated with chronic sleep deprivation.
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Affiliation(s)
- Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Aimee Morabito
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Emily Arentson-Lantz
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX, USA
| | - Olivia Knowles
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | | | - Dominique Condo
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.,Center for Sport Research (CSR), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Sarah Elizabeth Alexander
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Andrew Garnham
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Douglas Paddon-Jones
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX, USA
| | - Brad Aisbett
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
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Resistance Training and Skeletal Muscle Protein Metabolism in Eumenorrheic Females: Implications for Researchers and Practitioners. Sports Med 2020; 49:1637-1650. [PMID: 31190324 DOI: 10.1007/s40279-019-01132-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Resistance training is essential for health and performance and confers many benefits such as increasing skeletal muscle mass, increasing strength and power output, and improving metabolic health. Resistance training is a major component of the physical activity guidelines, yet research in female populations is limited. Recent increases in the promotion of, and the participation by, females in sport and exercise, highlight the need for an increase in understanding of evidence-based best practice exercise prescription for females. The aim of this review is to provide an overview of the current research regarding resistance training performance and skeletal muscle adaptation in females, with a focus on the hormonal variables that may influence resistance training outcomes. Findings suggest that the menstrual cycle phase may impact strength, but not skeletal muscle protein metabolism. In comparison, oral contraception use in females may reduce skeletal muscle protein synthesis, but not strength outcomes, when compared to non-users. Future research should investigate the role of resistance training in the maintenance of skeletal muscle protein metabolism during pregnancy, menopause and in athletes experiencing relative energy deficiency in sport. The review concludes with recommendations for researchers to assist them in the inclusion of female participants in resistance training research specifically, with commentary on the most appropriate methods of controlling for, or understanding the implications of, hormonal fluctuations. For practitioners, the current evidence suggests possible resistance training practices that could optimise performance outcomes in females, although further research is warranted.
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Mosoni L, Jarzaguet M, David J, Polakof S, Savary-Auzeloux I, Rémond D, Dardevet D. Post Meal Energy Boluses Do Not Increase the Duration of Muscle Protein Synthesis Stimulation in Two Anabolic Resistant Situations. Nutrients 2019; 11:E727. [PMID: 30934871 PMCID: PMC6520703 DOI: 10.3390/nu11040727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/11/2019] [Accepted: 03/27/2019] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND When given in the long term, whey proteins alone do not appear to be an optimal nutritional strategy to prevent or slow down muscle wasting during aging or catabolic states. It has been hypothesized that the digestion of whey may be too rapid during a catabolic situation to sustain the anabolic postprandial amino acid requirement necessary to elicit an optimal anabolic response. Interestingly, it has been shown recently that the duration of the postprandial stimulation of muscle protein synthesis in healthy conditions can be prolonged by the supplementary ingestion of a desynchronized carbohydrate load after food intake. We verified this hypothesis in the present study in two different cases of muscle wasting associated with anabolic resistance, i.e., glucocorticoid treatment and aging. METHODS Multi-catheterized minipigs were treated or not with glucocorticoids for 8 days. Muscle protein synthesis was measured sequentially over time after the infusion of a 13C phenylalanine tracer using the arterio-venous method before and after whey protein meal ingestion. The energy bolus was given 150 min after the meal. For the aging study, aged rats were fed the whey meal and muscle protein synthesis was measured sequentially over time with the flooding dose method using 13C Valine. The energy bolus was given 210 min after the meal. RESULTS Glucocorticoid treatment resulted in a decrease in the duration of the stimulation of muscle protein synthesis. The energy bolus given after food intake was unable to prolong this stimulation despite a simultaneous increase of insulin and glucose following its absorption. In old rats, a similar observation was made with no effect of the energy bolus on the duration of the muscle anabolic response following whey protein meal intake. CONCLUSIONS Despite very promising observations in healthy situations, the strategy aimed at increasing muscle protein synthesis stimulation by giving an energy bolus during the postprandial period remained inefficient in our two anabolic resistance models.
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Affiliation(s)
- Laurent Mosoni
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Marianne Jarzaguet
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Jérémie David
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Sergio Polakof
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Isabelle Savary-Auzeloux
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Didier Rémond
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
| | - Dominique Dardevet
- Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, UMR1019, F-63000 Clermont-Ferrand, France.
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Revel A, Jarzaguet M, Peyron MA, Papet I, Hafnaoui N, Migné C, Mosoni L, Polakof S, Savary-Auzeloux I, Rémond D, Dardevet D. At same leucine intake, a whey/plant protein blend is not as effective as whey to initiate a transient post prandial muscle anabolic response during a catabolic state in mini pigs. PLoS One 2017; 12:e0186204. [PMID: 29045496 PMCID: PMC5646799 DOI: 10.1371/journal.pone.0186204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/27/2017] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Muscle atrophy has been explained by an anabolic resistance following food intake and an increase of dietary protein intake is recommended. To be optimal, a dietary protein has to be effective not only to initiate but also to prolong a muscle anabolic response in a catabolic state. To our knowledge, whether or not a dairy or a dairy/plant protein blend fulfills these criterions is unknown in a muscle wasting situation. OBJECTIVE Our aim was, in a control and a catabolic state, to measure continuously muscle anabolism in term of intensity and duration in response to a meal containing casein (CAS), whey (WHEY) or a whey/ plant protein blend (BLEND) and to evaluate the best protein source to elicit the best post prandial anabolism according to the physio-pathological state. METHODS Adult male Yucatan mini pigs were infused with U-13C-Phenylalanine and fed either CAS, WHEY or BLEND. A catabolic state was induced by a glucocorticoid treatment for 8 days (DEX). Muscle protein synthesis, proteolysis and balance were measured with the hind limb arterio-venous differences technique. Repeated time variance analysis were used to assess significant differences. RESULTS In a catabolic situation, whey proteins were able to initiate muscle anabolism which remained transient in contrast to the stimulated muscle protein accretion with WHEY, CAS or BLEND in healthy conditions. Despite the same leucine intake compared to WHEY, BLEND did not restore a positive protein balance in DEX animals. CONCLUSIONS Even with WHEY, the duration of the anabolic response was not optimal and has to be improved in a catabolic state. The use of BLEND remained of lower efficiency even at same leucine intake than whey.
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Affiliation(s)
- Aurélia Revel
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Marianne Jarzaguet
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Marie-Agnès Peyron
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Isabelle Papet
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Noureddine Hafnaoui
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Carole Migné
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Laurent Mosoni
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Sergio Polakof
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Isabelle Savary-Auzeloux
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Didier Rémond
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
| | - Dominique Dardevet
- Université Clermont Auvergne, INRA, UNH, Unité de Nutrition Humaine, PFEM, MetaboHUB-Clermont, CRNH Auvergne, Clermont-Ferrand, France
- * E-mail:
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Baum JI, Kim IY, Wolfe RR. Protein Consumption and the Elderly: What Is the Optimal Level of Intake? Nutrients 2016; 8:nu8060359. [PMID: 27338461 PMCID: PMC4924200 DOI: 10.3390/nu8060359] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 12/14/2022] Open
Abstract
Maintaining independence, quality of life, and health is crucial for elderly adults. One of the major threats to living independently is the loss of muscle mass, strength, and function that progressively occurs with aging, known as sarcopenia. Several studies have identified protein (especially the essential amino acids) as a key nutrient for muscle health in elderly adults. Elderly adults are less responsive to the anabolic stimulus of low doses of amino acid intake compared to younger individuals. However, this lack of responsiveness in elderly adults can be overcome with higher levels of protein (or essential amino acid) consumption. The requirement for a larger dose of protein to generate responses in elderly adults similar to the responses in younger adults provides the support for a beneficial effect of increased protein in older populations. The purpose of this review is to present the current evidence related to dietary protein intake and muscle health in elderly adults.
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Affiliation(s)
- Jamie I Baum
- Department of Food Science, University of Arkansas, 2650 N. Young Ave, Fayetteville, AR 72704, USA.
| | - Il-Young Kim
- Department of Geriatrics, the Center for Translational Research on Aging and Longevity, Donald W. Reynolds Institute on Aging, College of Medicine, The University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Robert R Wolfe
- Department of Geriatrics, the Center for Translational Research on Aging and Longevity, Donald W. Reynolds Institute on Aging, College of Medicine, The University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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The Link between Dietary Protein Intake, Skeletal Muscle Function and Health in Older Adults. Healthcare (Basel) 2015; 3:529-43. [PMID: 27417778 PMCID: PMC4939566 DOI: 10.3390/healthcare3030529] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/24/2015] [Accepted: 06/29/2015] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscle mass and function are progressively lost with age, a condition referred to as sarcopenia. By the age of 60, many older adults begin to be affected by muscle loss. There is a link between decreased muscle mass and strength and adverse health outcomes such as obesity, diabetes and cardiovascular disease. Data suggest that increasing dietary protein intake at meals may counterbalance muscle loss in older individuals due to the increased availability of amino acids, which stimulate muscle protein synthesis by activating the mammalian target of rapamycin (mTORC1). Increased muscle protein synthesis can lead to increased muscle mass, strength and function over time. This review aims to address the current recommended dietary allowance (RDA) for protein and whether or not this value meets the needs for older adults based upon current scientific evidence. The current RDA for protein is 0.8 g/kg body weight/day. However, literature suggests that consuming protein in amounts greater than the RDA can improve muscle mass, strength and function in older adults.
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Paddon-Jones D, Campbell WW, Jacques PF, Kritchevsky SB, Moore LL, Rodriguez NR, van Loon LJ. Protein and healthy aging. Am J Clin Nutr 2015; 101:1339S-1345S. [PMID: 25926511 DOI: 10.3945/ajcn.114.084061] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Our understanding of the potential benefits and challenges of optimizing dietary protein intake in older adults continues to evolve. An overarching hypothesis generated during Protein Summit 2.0 was that consuming an adequate amount of high-quality protein at each meal, in combination with physical activity, may delay the onset of sarcopenia, slow its progression, reduce the magnitude of its functional consequences, or all of these. The potential benefits of young and middle-aged adults adopting a diet pattern whereby adequate protein is consumed at each meal as a countermeasure to sarcopenia are presented and discussed. For example, meeting a protein threshold (∼25-30 g/meal) represents a promising, yet still largely unexplored dietary strategy to help maintain muscle mass and function. For many older adults, breakfast is a carbohydrate-dominated lower-protein meal and represents an opportunity to improve and more evenly distribute daily protein intake. Although both animal and plant-based proteins can provide the required essential amino acids for health, animal proteins generally have a higher proportion of the amino acid leucine. Leucine plays a key role in stimulating translation initiation and muscle protein anabolism and is the focus of ongoing research. Protein requirements should be assessed in the light of habitual physical activity. An evenly distributed protein diet provides a framework that allows older adults to benefit from the synergistic anabolic effect of protein and physical activity. To fully understand the role of dietary protein intake in healthy aging, greater efforts are needed to coordinate and integrate research design and data acquisition and interpretation from a variety of disciplines.
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Affiliation(s)
- Douglas Paddon-Jones
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Wayne W Campbell
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Paul F Jacques
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Stephen B Kritchevsky
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Lynn L Moore
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Nancy R Rodriguez
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
| | - Luc Jc van Loon
- From the Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, TX (DP-J); the Department of Nutrition Science, Purdue University, West Lafayette, IN (WWC); the Jean Mayer USDA Human Nutrition Research Center, Tufts University, Boston, MA (PFJ); Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC (SBK); the Department of Medicine, Boston University, Boston, MA (LLM); the Department of Nutritional Sciences, University of Connecticut, Storrs, CT (NRR); and the NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands (LJCvL)
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10
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Messinger-Rapport BJ, Gammack JK, Thomas DR, Morley JE. Clinical update on nursing home medicine: 2013. J Am Med Dir Assoc 2014; 14:860-76. [PMID: 24286710 DOI: 10.1016/j.jamda.2013.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 09/18/2013] [Indexed: 12/18/2022]
Abstract
This is the seventh article in the series of Clinical Updates on Nursing Home Care. The topics covered are antiresorptive drugs, hip fracture, hypertension, orthostatic hypotension, depression, undernutrition, anorexia, cachexia, sarcopenia, exercise, pain, and behavioral and psychological symptoms of dementia.
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11
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Wandrag L, Brett SJ, Frost G, Hickson M. Impact of supplementation with amino acids or their metabolites on muscle wasting in patients with critical illness or other muscle wasting illness: a systematic review. J Hum Nutr Diet 2014; 28:313-30. [DOI: 10.1111/jhn.12238] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- L. Wandrag
- Department of Investigative Medicine; Nutrition and Dietetic Research Group; Imperial College London; London UK
| | - S. J. Brett
- Centre for Peri-operative Medicine and Critical Care Research; Imperial College Healthcare NHS Trust; London UK
| | - G. Frost
- Department of Investigative Medicine; Nutrition and Dietetic Research Group; Imperial College London; London UK
| | - M. Hickson
- Department of Investigative Medicine; Nutrition and Dietetic Research Group; Imperial College London; London UK
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12
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Abstract
Loss of lean body develops from an imbalance in protein synthesis and catabolism and is associated with a variety of different disease and nondisease states, including severe malnutrition, cachexia, and physiologic age-related loss (sarcopenia). Loss of lean body mass is prevalent among a significant proportion of the elderly population and has been associated with increased adverse clinical outcomes. Recognition of individuals at risk for low lean body mass may be difficult due to unequal distribution of losses across muscle and adipose compartments, and individuals who are both obese and sarcopenic demonstrate the highest risk for adverse events. Cross-sectional imaging modalities provide an accessible and easily interpretable means of quantifying lean muscle content and are routine diagnostic tests for cancer patients. As a result, a growing body of literature has developed characterizing the importance of low lean body mass as a poor prognostic factor among cancer patients, regardless of age. Cancer patients, especially those with sarcopenic obesity, are at increased risk for treatment-related toxicities from chemotherapy and increased overall mortality. Further investigations into the pathogenesis of muscle wasting among cancer patients are critical, as therapeutic oncologic interventions may inadvertently accelerate muscle catabolism. This review provides an overview of the definitions of low lean body mass, etiologic causes, clinical significance among cancer patients, and potential therapeutic interventions.
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Affiliation(s)
- Susan Tsai
- Department of Surgery, Division of Surgical Oncology, Medical College of Wisconsin, Milwaukee, WI 53226-3596, USA.
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13
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Smith GI, Patterson BW, Mittendorfer B. Human muscle protein turnover--why is it so variable? J Appl Physiol (1985) 2010; 110:480-91. [PMID: 21109595 DOI: 10.1152/japplphysiol.00125.2010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We undertook a comprehensive review of the literature to unravel the nature of the variability in the reported rate of human muscle protein synthesis. We analyzed the results from studies that report the protein fractional synthesis rate (FSR) in the vastus lateralis in healthy, nonobese, untrained adults ≤50 yr of age in the postabsorptive state at rest by using the primed, constant tracer amino acid infusion method according to experimental design characteristics. We hypothesized that if the variability is methodological (rather than physiological) in nature, systematic clustering of FSR values would be evident, and outliers would become apparent. Overall, as expected, the mixed muscle protein FSR values were significantly (P < 0.001) greater when the muscle vs. the plasma free amino acid enrichment is used as the surrogate precursor pool enrichment, and the average mixed muscle protein FSR values were significantly greater (P = 0.05) than the myofibrillar/myosin heavy chain FSR values. The within-study variability (i.e., population variance) was somewhat smaller in studies that used plasma amino acid/ketoacid enrichments vs. muscle free amino acid enrichment (∼24 vs. ∼31%), but this was not apparent in all circumstances. Furthermore, the between-study consistency of measured FSR values (i.e., interquartile range) was inversely correlated with the average duration between biopsies. Aside from that, the variation in reported FSR values could not be explained by differences in the experimental design and analytical methods, and none of the most commonly used approaches stood out as clearly superior in terms of consistency of results and/or within-study variability. We conclude that the variability in reported values is in part due to 1) differences in experimental design (e.g., choice of precursor pool) and 2) considerable within-subject variability. The summary of the results from our analysis can be used as guidelines for "normal" average basal FSR values at rest in healthy adults.
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Affiliation(s)
- Gordon I Smith
- Division of Geriatrics and Nutritional Science, Washington Univ. School of Medicine, 660 South Euclid Ave., Campus Box 8031, St. Louis, MO 63110, USA
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14
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Noreen EE, Sass MJ, Crowe ML, Pabon VA, Brandauer J, Averill LK. Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults. J Int Soc Sports Nutr 2010; 7:31. [PMID: 20932294 PMCID: PMC2958879 DOI: 10.1186/1550-2783-7-31] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 10/08/2010] [Indexed: 12/31/2022] Open
Abstract
Background To determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults. Methods A total of 44 men and women (34 ± 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearson's r. Results Compared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ± 0.5 kg, SO = -0.1 ± 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ± 1.3 kg, SO = +0.2 ± 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ± 1.3% body fat, SO = +0. 3 ± 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ± 0.9 kg, SO = +0.2 ± 0.8 kg), RMR (FO = +17 ± 260 kcal, SO = -62 ± 184 kcal) or respiratory exchange ratio (FO = -0.02 ± 0.09, SO = +0.02 ± 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ± 0.142 μg/dL, SO = +0.016 ± 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001). Conclusion 6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.
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Affiliation(s)
- Eric E Noreen
- Department of Health Sciences, Gettysburg College, Gettysburg Pennsylvania, USA.
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15
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Burckart K, Beca S, Urban RJ, Sheffield-Moore M. Pathogenesis of muscle wasting in cancer cachexia: targeted anabolic and anticatabolic therapies. Curr Opin Clin Nutr Metab Care 2010; 13:410-6. [PMID: 20473155 PMCID: PMC4618842 DOI: 10.1097/mco.0b013e328339fdd2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Cancer-related muscle loss, or cachexia, is the cause of death for approximately 2 million people worldwide and severely reduces quality of life. The degree of cachexia is inversely correlated with survival time; however, the exact mechanisms behind cancer-induced muscle wasting remain under investigation. RECENT FINDINGS Cytokines such as tumor necrosis factor-alpha trigger degradatory pathways through nuclear factor-kappaB signaling that activate the ubiquitin-proteasome system and muscle proteolysis. Androgen treatment has been shown to reduce inflammatory cytokines and even stimulate anti-inflammatory cytokine production. Amino acid supplementation has been shown to induce muscle protein synthesis in ovarian cancer patients. SUMMARY Targeted anabolic therapies aimed at preventing or reversing cancer cachexia might involve the combined use of androgens and amino acids working concurrently to enhance muscle protein synthesis and reduce muscle protein breakdown. Additional focused clinical studies are needed to identify muscle-specific targets or biomarkers for defined therapeutic approaches to slow or prevent cancer cachexia. In this review, we summarize the pathogenesis of cancer-related muscle wasting and discuss potential interventions at reversing or preventing cancer-related muscle loss.
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Affiliation(s)
- Kimberlee Burckart
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX
| | - Sorin Beca
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX
| | - Randall J. Urban
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX
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16
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Cree MG, Paddon-Jones D, Newcomer BR, Ronsen O, Aarsland A, Wolfe RR, Ferrando A. Twenty-eight-day bed rest with hypercortisolemia induces peripheral insulin resistance and increases intramuscular triglycerides. Metabolism 2010; 59:703-10. [PMID: 19919871 PMCID: PMC2856785 DOI: 10.1016/j.metabol.2009.09.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 09/12/2009] [Accepted: 09/15/2009] [Indexed: 01/03/2023]
Abstract
Spaceflight represents a unique physiologic challenge to humans, altering hormonal profiles and tissue insulin sensitivity. Among these hormonal alterations, hypercortisolemia and insulin insensitivity are thought to negatively affect muscle mass and function with spaceflight. As insulin sensitivity influences the accumulation of muscle triglycerides, we examined this relationship during hypercortisolemia and inactivity. Six young healthy volunteers were confined to bed rest for 28 days. To mimic the stress response observed during spaceflight, hypercortisolemia (20-24 mg/dL) was induced and maintained by oral ingestion of hydrocortisone. On days 1 and 28 of bed rest, insulin sensitivity across the leg was assessed with a local (femoral arterial insulin infusion) 2-stage hyperinsulinemic-euglycemic clamp (stage 1, 35 microU/min per milliliter of leg; stage 2, 70 microU/min per milliliter of leg). Intramuscular lipid was measured with magnetic resonance spectroscopy. After bed rest, there was a decrease in insulin sensitivity, as assessed by glucose uptake during hyperinsulinemia (from 9.1 +/- 1.3 [mean +/- SEM] to 5.2 +/- 0.7 mg/kg of leg per minute [P = .015]). Intramuscular triglyceride increased from 0.077 +/- 0.011 to 0.136 +/- 0.018 (signal area of fat/signal area of standard, P = .009). Intramuscular lipid content correlated with the glucose uptake at day 28 (R = -0.85, P = .035). These data demonstrate that muscular inactivity and hypercortisolemia are associated with an increase in intramuscular triglyceride and skeletal muscle insulin resistance in previously healthy subjects.
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Affiliation(s)
- Melanie G Cree
- Metabolism Unit, Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston TX 77550, USA
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18
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Nutrition Support. Crit Care Med 2008. [DOI: 10.1016/b978-032304841-5.50085-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Thomas DR. Loss of skeletal muscle mass in aging: Examining the relationship of starvation, sarcopenia and cachexia. Clin Nutr 2007; 26:389-99. [PMID: 17499396 DOI: 10.1016/j.clnu.2007.03.008] [Citation(s) in RCA: 324] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 03/13/2007] [Accepted: 03/18/2007] [Indexed: 12/25/2022]
Abstract
A loss of body weight or skeletal muscle mass is common in older persons and is a harbinger of poor outcome. Involuntary weight loss can be categorized into three primary etiologies of starvation, sarcopenia, and cachexia. Starvation results in a loss of body fat and non-fat mass due to inadequate intake of protein and energy. Sarcopenia is associated with a reduction in muscle mass and strength occurring with normal aging, associated with a reduction in motor unit number and atrophy of muscle fibers, especially the type IIa fibers. The loss of muscle mass with aging is clinically important because it leads to diminished strength and exercise capacity. Cachexia is widely recognized as severe wasting accompanying disease states such as cancer or immunodeficiency disease, but does not have a universally accepted definition. The key clinical question is whether these changes in body composition are distinct entities or represent an interdependent continuum. The importance of defining the distinction lies in developing a targeted therapeutic approach to skeletal muscle loss and muscle strength in older persons. Failure to distinguish among these causes of skeletal muscle loss often results in frustration over the clinical response to therapeutic interventions.
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Affiliation(s)
- David R Thomas
- Division of Geriatric Medicine, Saint Louis University Medical Center, Saint Louis, MO 63104, USA.
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Raj DSC, Adeniyi O, Dominic EA, Boivin MA, McClelland S, Tzamaloukas AH, Morgan N, Gonzales L, Wolfe R, Ferrando A. Amino acid repletion does not decrease muscle protein catabolism during hemodialysis. Am J Physiol Endocrinol Metab 2007; 292:E1534-42. [PMID: 17264222 DOI: 10.1152/ajpendo.00599.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Intradialytic protein catabolism is attributed to loss of amino acids in the dialysate. We investigated the effect of amino acid infusion during hemodialysis (HD) on muscle protein turnover and amino acid transport kinetics by using stable isotopes of phenylalanine, leucine, and lysine in eight patients with end-stage renal disease (ESRD). Subjects were studied at baseline (pre-HD), 2 h of HD without amino acid infusion (HD-O), and 2 h of HD with amino acid infusion (HD+AA). Amino acid depletion during HD-O augmented the outward transport of amino acids from muscle into the vein. Increased delivery of amino acids to the leg during HD+AA facilitated the transport of amino acids from the artery into the intracellular compartment. Increase in muscle protein breakdown was more than the increase in synthesis during HD-O (46.7 vs. 22.3%, P < 0.001). Net balance (nmol.min(-1).100 ml (-1)) was more negative during HD-O compared with pre-HD (-33.7 +/- 1.5 vs. -6.0 +/- 2.3, P < 0.001). Despite an abundant supply of amino acids, the net balance (-16.9 +/- 1.8) did not switch from net release to net uptake. HD+AA induced a proportional increase in muscle protein synthesis and catabolism. Branched chain amino acid catabolism increased significantly from baseline during HD-O and did not decrease during HD+AA. Protein synthesis efficiency, the fraction of amino acid in the intracellular pool that is utilized for muscle protein synthesis decreased from 42.1% pre-HD to 33.7 and 32.6% during HD-O and HD+AA, respectively (P < 0.01). Thus amino acid repletion during HD increased muscle protein synthesis but did not decrease muscle protein breakdown.
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Affiliation(s)
- Dominic S C Raj
- Division of Nephrology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-5271, USA.
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Killewich LA, Tuvdendorj D, Bahadorani J, Hunter GC, Wolfe RR. Amino acids stimulate leg muscle protein synthesis in peripheral arterial disease. J Vasc Surg 2007; 45:554-9; discussion 559-60. [PMID: 17321342 DOI: 10.1016/j.jvs.2006.11.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 11/10/2006] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Older patients with peripheral arterial disease (PAD) and intermittent claudication have impaired walking ability resulting from reduced lower extremity blood flow. Evidence suggests that leg muscle abnormalities may also contribute to walking intolerance in claudicants. In healthy elderly people, leg muscle protein synthesis can be augmented by nutritional supplementation with amino acids; preliminary data suggest that this increases muscle mass, walking ability, and functional status. In this study, we investigated whether amino acid supplementation would improve leg muscle protein synthesis in elderly PAD subjects, given that reduced leg blood flow might restrict the availability of amino acids to muscle. METHODS Two groups participated in the study: a group of 11 claudicants (mean age, 62 years; mean ankle-brachial index, 0.62; 46% male) and a group of 9 age- and sex-matched healthy controls (mean ankle-brachial index, 1.1). Both groups underwent measurement of leg blood flow by using strain gauge plethysmography, as well as measurement of baseline and amino acid-stimulated protein synthesis in leg muscle. Protein synthesis was quantified from calf muscle biopsy samples by measurement of the fractional synthetic rate (FSR) of protein, by using the incorporation of the stable isotope l-[ring-(2)H(5)]-phenylalanine into muscle protein. Total protein was extracted from muscle samples, and gas chromatography/mass spectroscopy methodology was used to measure incorporation rates. After measurement of basal FSR, all subjects were given an oral drink of 15 g of essential amino acids, and the measurements of FSR were repeated. Data are expressed as mean +/- SD; statistical analysis of differences between the two groups (with and without amino acid supplementation) was performed by using analysis of variance with repeated measures. RESULTS Calf blood flow was reduced in the PAD subjects compared with controls (1.44 +/- 0.53 mL/min per 100 mg of tissue vs 2.40 +/- 0.57 mL/min per 100 mg of tissue; P = .005; t test). FSR in the basal state was equivalent between the two groups (healthy, 0.060% +/- 0.025% per hour; PAD, 0.061% +/- 0.029% per hour; P = .97). Equivalent increases (P < .05) occurred in both groups in response to oral amino acid supplementation (healthy, 0.087% +/- 0.012% per hour; PAD, 0.104% +/- 0.041% per hour; P > .05; analysis of variance). CONCLUSIONS Despite reduced leg blood flow, elderly PAD patients synthesize calf muscle protein in the basal state in a fashion similar to that in healthy elderly people. More importantly, administration of exogenous amino acids produces a significant increase in protein synthesis in these patients that is also equivalent to that in healthy elderly people. Our goal is to use these results as the basis for an intervention study to determine whether long-term oral amino acids, by augmenting calf muscle protein synthesis, increase calf muscle mass, walking ability, and functional status in elderly claudicants.
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Affiliation(s)
- Lois A Killewich
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555, USA.
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Hoffman JR, Ratamess NA, Kang J, Falvo MJ, Faigenbaum AD. Effect of protein intake on strength, body composition and endocrine changes in strength/power athletes. J Int Soc Sports Nutr 2006; 3:12-8. [PMID: 18500968 PMCID: PMC2129168 DOI: 10.1186/1550-2783-3-2-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Accepted: 11/08/2006] [Indexed: 11/16/2022] Open
Abstract
Comparison of protein intakes on strength, body composition and hormonal changes were examined in 23 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were stratified into three groups depending upon their daily consumption of protein; below recommended levels (BL; 1.0 - 1.4 g.kg-1.day-1; n = 8), recommended levels (RL; 1.6 - 1.8 g.kg-1.day-1; n = 7) and above recommended levels (AL; > 2.0 g.kg-1.day-1; n = 8). Subjects were assessed for strength [one-repetition maximum (1-RM) bench press and squat] and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, and insulin-like growth factor. No differences were seen in energy intake (3,171 +/- 577 kcal) between the groups, and the energy intake for all groups were also below the recommended levels for strength/power athletes. No significant changes were seen in body mass, lean body mass or fat mass in any group. Significant improvements in 1-RM bench press and 1-RM squat were seen in all three groups, however no differences between the groups were observed. Subjects in AL experienced a 22% and 42% greater change in Delta 1-RM squat and Delta 1-RM bench press than subjects in RL, however these differences were not significant. No significant changes were seen in any of the resting hormonal concentrations. The results of this study do not provide support for protein intakes greater than recommended levels in collegiate strength/power athletes for body composition improvements, or alterations in resting hormonal concentrations.
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Paddon-Jones D, Sheffield-Moore M, Cree MG, Hewlings SJ, Aarsland A, Wolfe RR, Ferrando AA. Atrophy and impaired muscle protein synthesis during prolonged inactivity and stress. J Clin Endocrinol Metab 2006; 91:4836-41. [PMID: 16984982 DOI: 10.1210/jc.2006-0651] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
CONTEXT We recently demonstrated that 28-d bed rest in healthy volunteers results in a moderate loss of lean leg mass and strength. OBJECTIVE The objective of this study was to quantify changes in muscle protein kinetics, body composition, and strength during a clinical bed rest model reflecting both physical inactivity and the hormonal stress response to injury or illness. DESIGN Muscle protein kinetics were calculated during a primed, continuous infusion (0.08 micromol/kg.min) of 13C6-phenylalanine on d 1 and 28 of bed rest. SETTING The setting for this study was the General Clinical Research Center at the University of Texas Medical Branch. PARTICIPANTS Participants were healthy male volunteers (n = 6, 28 +/- 2 yr, 84 +/- 4 kg, 178 +/- 3 cm). INTERVENTION During bed rest, hydrocortisone sodium succinate was administered iv (d 1 and 28) and orally (d 2-27) to reproduce plasma cortisol concentrations consistent with trauma or illness (approximately 22 microg/dl). MAIN OUTCOME MEASURES We hypothesized that inactivity and hypercortisolemia would reduce lean muscle mass, leg extension strength, and muscle protein synthesis. RESULTS Volunteers experienced a 28.4 +/- 4.4% loss of leg extension strength (P = 0.012) and a 3-fold greater loss of lean leg mass (1.4 +/- 0.1 kg) (P = 0.004) compared with our previous bed rest-only model. Net protein catabolism was primarily due to a reduction in muscle protein synthesis [fractional synthesis rate, 0.081 +/- 0.004 (d 1) vs. 0.054 +/- 0.007%/h (d 28); P = 0.023]. There was no change in muscle protein breakdown. CONCLUSION Prolonged inactivity and hypercortisolemia represents a persistent catabolic stimulus that exacerbates strength and lean muscle loss via a chronic reduction in muscle protein synthesis.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Surgery, The University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77550, USA.
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25
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Siew ED, Pupim LB, Majchrzak KM, Shintani A, Flakoll PJ, Ikizler TA. Insulin resistance is associated with skeletal muscle protein breakdown in non-diabetic chronic hemodialysis patients. Kidney Int 2006; 71:146-52. [PMID: 17063174 DOI: 10.1038/sj.ki.5001984] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Deranged protein metabolism is known to complicate uremia. Insulin resistance is evident in chronic hemodialysis (CHD) patients. We hypothesized that the degree of insulin resistance would predict protein catabolism in non-diabetic CHD patients. We examined the relationship between Homeostasis Model Assessment (HOMA) and fasting whole-body and skeletal muscle protein turnover in 18 non-diabetic CHD patients using primed-constant infusions of L-(1-(13)C) leucine and L-(ring-(2)H(5)) phenylalanine. Mean+/-s.d. fasting glucose and body mass index were 80.6+/-9.8 mg/dl and 25.4+/-4.4 kg/m(2), respectively. Median (interquartile range) HOMA was 1.6 (1.4, 3.9). Mean+/-s.e.m. skeletal muscle protein synthesis, breakdown, and net balance were 89.57+/-11.67, 97.02+/-13.3, and -7.44+/-7.14 microg/100 ml/min, respectively. Using linear regression, a positive correlation was observed between HOMA and skeletal muscle protein synthesis (R(2)=0.28; P=0.024), and breakdown (R(2)=0.49; P=0.001). An inverse association between net skeletal muscle protein balance and HOMA was also noted (R(2)=0.20; P=0.066). After adjustment for C-reactive protein, only the relationship between HOMA and skeletal muscle protein breakdown persisted (R(2)=0.49; P=0.006). There were no significant associations between components of whole-body protein turnover and HOMA. This study demonstrates that insulin resistance is evident in non-diabetic dialysis patients, is associated with skeletal muscle protein breakdown, and represents a novel target for intervention in uremic wasting.
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Affiliation(s)
- E D Siew
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2372, USA
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Paddon-Jones D. Interplay of stress and physical inactivity on muscle loss: Nutritional countermeasures. J Nutr 2006; 136:2123-6. [PMID: 16857828 DOI: 10.1093/jn/136.8.2123] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Inactivity-mediated protein catabolism occurs in many circumstances ranging from catastrophic events such as severe illness or injury, to unique environments such as spaceflight/microgravity, to more insidious causes such as physical frailty and the progression of aging. Nevertheless, regardless of the etiology, the consequences of inactivity are readily observable and debilitating. Mechanistically, the loss of lean body mass during inactivity is the result of a chronic imbalance between muscle protein synthesis and breakdown. When inactivity is accompanied by the stress of trauma or disease, the rate of muscle protein catabolism can increase several fold. Bed rest studies in healthy volunteers provide a unique opportunity to examine the mechanisms contributing to muscle loss and evaluate strategies for intervention that may slow muscle catabolism and promote anabolism. The prerequisite for muscle protein synthesis and the most readily adaptable stimulus is dietary-derived amino acids. This review focuses on the role of amino acid supplementation in the maintenance of skeletal muscle mass during age-related and clinically mandated inactivity.
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Abstract
PURPOSE OF REVIEW The loss of skeletal muscle with injury or critical illness can be dramatic. This review emphasizes the importance of skeletal muscle as a metabolic reserve. Changes in protein metabolism with bed rest alone and during physiological stress are discussed. Nutritional and hormonal interventions that ameliorate the loss of skeletal muscle are highlighted. RECENT FINDINGS The loss of skeletal muscle that occurs with inactivity alone can be prevented by nutritional supplementation with an essential amino acid formula. Bed rest with accompanying hypercortisolemia produces a threefold greater loss of skeletal muscle than bed rest alone. Essential amino acids stimulate muscle anabolism during acute hypercortisolemia; however, their effects during chronic hypercortisolemia must be explored. SUMMARY Skeletal muscle loss with trauma or critical illness is due in great part to the interaction of bed rest (muscular inactivity) and stress (hypercortisolemia). Younger individuals respond to nutritional and pharmacological interventions during bed rest alone. Given a lower relative lean mass in the elderly and the importance of skeletal muscle as a metabolic reserve during stress, it is understandable that clinical outcomes are worse in older patients. Countermeasures to the loss of skeletal muscle, especially in the stressed patient, must be developed.
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Affiliation(s)
- Arny A Ferrando
- Department of Surgery, University of Texas Medical Branch, Shrine Hospital for Children, Galveston, Texas 77550, USA.
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Koutkia P, Berry J, Eaton K, Breu J, Grinspoon S. Increased adrenal androgen secretion with inhibition of 11beta-hydroxylase in HIV-infected women. Am J Physiol Endocrinol Metab 2006; 290:E808-13. [PMID: 16303845 DOI: 10.1152/ajpendo.00418.2005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adrenal androgen production is reduced in association with disease severity in HIV-infected women. This response may be maladaptive in terms of maintenance of lean body mass, functional status, and immune function. The aim of this study was to assess whether the use of an adrenal enzyme inhibitor of 11beta-hydroxylase might increase androgen production in this population. We conducted a randomized, double-blind, placebo-controlled study of metyrapone (500 mg p.o. qid) or placebo for 2 wk in 10 HIV-infected women with AIDS wasting [weight <90% ideal body weight (IBW) or weight loss >10%] and reduced androgen levels. Basal and ACTH-stimulated androgen, mineralocorticoid, and glucocorticoid levels were measured at baseline and after 14 days of treatment. Subjects were similar in age (40.9 +/- 0.9 yr), weight (91.7 +/- 3.5% IBW) and hormone concentrations at study entry. Total testosterone (84 +/- 54 vs. -0.4 +/- 2 ng/dl, P = 0.024), free testosterone (6.5 +/- 2.8 vs. 0.1 +/- 0.1 pg/ml, P = 0.024), DHEA (5.0 +/- 3.2 vs. -0.6 +/- 0.5 microg/l, P = 0.024), and 11-deoxycortisol (2,145 +/- 820 vs. -14 +/- 22 ng/dl, P = 0.024) levels increased in response to metyrapone compared with placebo treatment. In response to ACTH, significant increases in the DHEA/cortisol ratio (174 +/- 48 vs. 3 +/- 3, P = 0.008) were seen in the metyrapone group compared with placebo. Blood pressure and electrolytes did not change, and signs of adrenal insufficiency were not apparent. These data demonstrate that inhibition of 11beta-hydroxylase with metyrapone increases adrenal androgen secretion in HIV-infected women. Further studies are needed to assess the physiological effects of this strategy to increase anabolic hormone levels in severe stress, including detailed testing to rule out the potential risk of concomitant adrenal insufficiency.
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Affiliation(s)
- Polyxeni Koutkia
- Program in Nutritional Metabolism and Neuroendocrine Unit, Mass General Hospital, Harvard Medical School, 55 Fruit St., Boston, MA 02114, USA
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29
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Bird SP, Tarpenning KM, Marino FE. Independent and combined effects of liquid carbohydrate/essential amino acid ingestion on hormonal and muscular adaptations following resistance training in untrained men. Eur J Appl Physiol 2006; 97:225-38. [PMID: 16456674 DOI: 10.1007/s00421-005-0127-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 12/15/2005] [Indexed: 11/27/2022]
Abstract
This investigation examined chronic alteration of the acute hormonal response associated with liquid carbohydrate (CHO) and/or essential amino acid (EAA) ingestion on hormonal and muscular adaptations following resistance training. Thirty-two untrained young men performed 12 weeks of resistance training twice a week, consuming ~675 ml of either, a 6% CHO solution, 6 g EAA mixture, combined CHO + EAA supplement or placebo (PLA). Blood samples were obtained pre- and post-exercise (week 0, 4, 8, and 12), for determination of glucose, insulin, and cortisol. 3-Methylhistidine excretion and muscle fibre cross-sectional area (fCSA) were determined pre- and post-training. Post-exercise cortisol increased (P<0.05) during each training phase for PLA. No change was displayed by EAA; CHO and CHO + EAA demonstrated post-exercise decreases (P<0.05). All groups displayed reduced pre-exercise cortisol at week 12 compared to week 0 (P<0.05). Post-exercise insulin concentrations showed no change for PLA; increases were observed for the treatment groups (P<0.05), which remained greater for CHO and CHO + EAA (P<0.001) than PLA. EAA and CHO ingestion attenuated 3-methylhistidine excretion 48 h following the exercise bout. CHO + EAA resulted in a 26% decrease (P<0.01), while PLA displayed a 52% increase (P<0.01). fCSA increased across groups for type I, IIa, and IIb fibres (P<0.05), with CHO + EAA displaying the greatest gains in fCSA relative to PLA (P<0.05). These data indicate that CHO + EAA ingestion enhances muscle anabolism following resistance training to a greater extent than either CHO or EAA consumed independently. The synergistic effect of CHO + EAA ingestion maximises the anabolic response presumably by attenuating the post-exercise rise in protein degradation.
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MESH Headings
- Adaptation, Physiological/drug effects
- Adult
- Amino Acids, Essential/administration & dosage
- Amino Acids, Essential/pharmacology
- Blood Glucose/metabolism
- Body Composition/physiology
- Dietary Carbohydrates/administration & dosage
- Dietary Carbohydrates/pharmacology
- Double-Blind Method
- Exercise/physiology
- Hormones/blood
- Humans
- Hydrocortisone/blood
- Insulin/blood
- Male
- Methylhistidines/urine
- Muscle Fibers, Fast-Twitch/cytology
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Slow-Twitch/cytology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/physiology
- Muscle, Skeletal/cytology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/physiology
- Time Factors
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Affiliation(s)
- Stephen P Bird
- School of Human Movement Studies, Charles Sturt University, Allen House 2.13, Bathurst, NSW, Australia.
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30
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Paddon-Jones D, Wolfe RR, Ferrando AA. Amino acid supplementation for reversing bed rest and steroid myopathies. J Nutr 2005; 135:1809S-1812S. [PMID: 15987870 DOI: 10.1093/jn/135.7.1809s] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Muscular inactivity is inherent in many circumstances, including convalescence from serious illness or injury, spaceflight, and the progression of aging. Inactivity in a healthy individual leads to a decrease in whole-body protein turnover composed primarily of a decrease in muscle protein synthesis. The decrease in muscle protein synthesis leads to a substantial loss of lean body mass. We have demonstrated that this loss of lean mass is greater when inactivity is accompanied by stress, specifically hypercortisolemia. During convalescence from trauma or injury, the anabolic stimulus provided by nutrient ingestion represents a primary means of ameliorating the loss of muscle protein. We have previously demonstrated that ingestion of essential amino acids (EAAs), formulated to mimic the proportion of EAAs in muscle, provides a potent anabolic stimulus for muscle protein. Recently, we demonstrated that EAA supplementation throughout 28 d of bed rest stimulated net muscle protein synthesis. The repeated stimulation translated to maintenance of lean body mass and an amelioration of functional decrement compared to a placebo treatment. We have also demonstrated that this EAA supplement stimulates net protein synthesis during acute hypercortisolemia and are currently testing the effects during prolonged inactivity. Although EAAs promote muscle anabolism during hypercortisolemia, it is unlikely that a nutritional intervention alone would be effective in maintaining lean body mass during severe stress. It may be necessary to concomitantly reduce the catabolic influence of cortisol or provide another anabolic stimulus.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Surgery, University of Texas Medical Branch, and Shriners Hospitals for Children, Galveston, TX, USA
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31
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Kerksick CM, Leutholtz B. Nutrient administration and resistance training. J Int Soc Sports Nutr 2005; 2:50-67. [PMID: 18500951 PMCID: PMC2129163 DOI: 10.1186/1550-2783-2-1-50] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Accepted: 06/11/2005] [Indexed: 11/10/2022] Open
Abstract
Skeletal muscle tissue is tightly regulated throughout our bodies by balancing its synthesis and breakdown. Many factors are known to exist that cause profound changes on the overall status of skeletal muscle, some of which include exercise, nutrition, hormonal influences and disease. Muscle hypertrophy results when protein synthesis is greater than protein breakdown. Resistance training is a popular form of exercise that has been shown to increase muscular strength and muscular hypertrophy. In general, resistance training causes a stimulation of protein synthesis as well as an increase in protein breakdown, resulting in a negative balance of protein. Providing nutrients, specifically amino acids, helps to stimulate protein synthesis and improve the overall net balance of protein. Strategies to increase the concentration and availability of amino acids after resistance exercise are of great interest and have been shown to effectively increase overall protein synthesis. 123 After exercise, providing carbohydrate has been shown to mildly stimulate protein synthesis while addition of free amino acids prior to and after exercise, specifically essential amino acids, causes a rapid pronounced increase in protein synthesis as well as protein balance.13 Evidence exists for a dose-response relationship of infused amino acids while no specific regimen exists for optimal dosing upon ingestion. Ingestion of whole or intact protein sources (e.g., protein powders, meal-replacements) has been shown to cause similar improvements in protein balance after resistance exercise when compared to free amino acid supplements. Future research should seek to determine optimal dosing of ingested intact amino acids in addition to identifying the cellular mechanistic machinery (e.g. transcriptional and translational mechanisms) for causing the increase in protein synthesis.
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Affiliation(s)
- Chad M Kerksick
- Exercise and Sport Nutrition Laboratory, Center for Exercise, Nutrition and Preventive Health Research, Department of Health, Human Performance and Recreation, Baylor University.
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32
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Paddon-Jones D, Sheffield-Moore M, Aarsland A, Wolfe RR, Ferrando AA. Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. Am J Physiol Endocrinol Metab 2005; 288:E761-7. [PMID: 15572657 DOI: 10.1152/ajpendo.00291.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to determine whether ingestion of a between-meal supplement containing 30 g of carbohydrate and 15 g of essential amino acids (CAA) altered the metabolic response to a nutritionally mixed meal in healthy, recreationally active male volunteers. A control group (CON; n = 6, 38 +/- 8 yr, 86 +/- 10 kg, 179 +/- 3 cm) received a liquid mixed meal [protein, 23.4 +/- 1.0 g (essential amino acids, 14.7 +/- 0.7 g); carbohydrate, 126.6 +/- 4.0 g; fat, 30.3 +/- 2.8 g] every 5 h (0830, 1330, 1830). The experimental group (SUP; n = 7, 36 +/- 10 yr, 87 +/- 12 kg, 180 +/- 3 cm) consumed the same meals but, in addition, were given CAA supplements (1100, 1600, 2100). Net phenylalanine balance (NB) and fractional synthetic rate (FSR) were calculated during a 16-h primed constant infusion of L-[ring-2H5]phenylalanine. Ingestion of a combination of CAA supplements and meals resulted in a greater mixed muscle FSR than ingestion of the meals alone (SUP, 0.099 +/- 0.008; CON, 0.076 +/- 0.005%/h; P < 0.05). Both groups experienced an improvement in NB after the morning (SUP, -2.2 +/- 3.3; CON, -1.5 +/- 3.5 nmol x min(-1) x 100 ml leg volume(-1)) and evening meals (SUP, -9.7 +/- 4.3; CON, -6.7 +/- 4.1 nmol x min(-1) x 100 ml leg volume(-1)). NB after CAA ingestion was significantly greater than after the meals, with values of 40.2 +/- 8.5 nmol x min(-1) x 100 ml leg volume(-1). These data indicate that CAA supplementation produces a greater anabolic effect than ingestion of intact protein but does not interfere with the normal metabolic response to a meal.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77550, USA.
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33
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Ferrando AA, Raj D, Wolfe RR. Amino acid control of muscle protein turnover in renal disease. J Ren Nutr 2005; 15:34-8. [DOI: 10.1053/j.jrn.2004.09.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Abstract
PURPOSE OF REVIEW This review highlights recent publications dealing with the nature of the in-vivo response of skeletal muscle to critical illness and approaches to attenuating this response. Studies focused on molecular mechanisms of muscle catabolism are not reviewed. RECENT FINDINGS The general areas covered are the metabolic response to stress, particularly regarding the relationship between muscle protein breakdown, amino acid availability, and muscle protein synthesis. The impact of the profile of amino acids in the context of protein/amino acid intake is also discussed. Advances in our understanding of the hormonal response are considered, and use of insulin therapy to slow muscle catabolism is discussed. SUMMARY Muscle catabolism is a fundamental response to severe stress, and the resulting amino acid efflux from muscle provides important precursors for protein synthesis in other parts of the body. The nature of this response (i.e. transport kinetics favoring efflux of amino acids from muscle) makes amelioration of the catabolic response of muscle with nutrition alone very difficult. Many approaches have been used to reverse catabolism, mostly involving various anabolic hormones. Recent studies using insulin therapy are particularly intriguing because of the low cost and powerful anabolic stimulus of insulin.
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Affiliation(s)
- Robert R Wolfe
- The University of Texas Medical Branch, Department of Surgery and Shriners Burns Hospital, Metabolism Unit, Galveston, Texas, USA.
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35
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Paddon-Jones D, Børsheim E, Wolfe RR. Potential ergogenic effects of arginine and creatine supplementation. J Nutr 2004; 134:2888S-2894S; discussion 2895S. [PMID: 15465806 DOI: 10.1093/jn/134.10.2888s] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The rationale for the use of nutritional supplements to enhance exercise capacity is based on the assumption that they will confer an ergogenic effect above and beyond that afforded by regular food ingestion alone. The proposed or advertised ergogenic effect of many supplements is based on a presumptive metabolic pathway and may not necessarily translate to quantifiable changes in a variable as broadly defined as exercise performance. L-arginine is a conditionally essential amino acid that has received considerable attention due to potential effects on growth hormone secretion and nitric oxide production. In some clinical circumstances (e.g., burn injury, sepsis) in which the demand for arginine cannot be fully met by de novo synthesis and normal dietary intake, exogenous arginine has been shown to facilitate the maintenance of lean body mass and functional capacity. However, the evidence that supplemental arginine may also confer an ergogenic effect in normal healthy individuals is less compelling. In contrast to arginine, numerous studies have reported that supplementation with the arginine metabolite creatine facilitates an increase in anaerobic work capacity and muscle mass when accompanied by resistance training programs in both normal and patient populations. Whereas improvement in the rate of phosphocreatine resynthesis is largely responsible for improvements in acute work capacity, the direct effect of creatine supplementation on skeletal muscle protein synthesis is less clear. The purpose of this review is to summarize the role of arginine and its metabolite creatine in the context of a nutrition supplement for use in conjunction with an exercise stimulus in both healthy and patient populations.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Surgery, The University of Texas Medical Branch and Metabolism Unit, Shriners Hospitals for Children, Galveston, TX 77550, USA
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Liu Z, Li G, Kimball SR, Jahn LA, Barrett EJ. Glucocorticoids modulate amino acid-induced translation initiation in human skeletal muscle. Am J Physiol Endocrinol Metab 2004; 287:E275-81. [PMID: 15039148 DOI: 10.1152/ajpendo.00457.2003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amino acids are unique anabolic agents in that they nutritively signal to mRNA translation initiation and serve as substrates for protein synthesis in skeletal muscle. Glucocorticoid excess antagonizes the anabolic action of amino acids on protein synthesis in laboratory animals. To examine whether excessive glucocorticoids modulate mixed amino acid-signaled translation initiation in human skeletal muscle, we infused an amino acid mixture (10% Travasol) systemically to 16 young healthy male volunteers for 6 h in the absence (n = 8) or presence (n = 8) of glucocorticoid excess (dexamethasone 2 mg orally every 6 h for 3 days). Vastus lateralis muscles were biopsied before and after amino acid infusion, and the phosphorylation of eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1), ribosomal protein S6 kinase (p70(S6K)), and eIF2alpha and the guanine nucleotide exchange activity of eIF2B were measured. Systemic infusion of mixed amino acids significantly stimulated the phosphorylation of 4E-BP1 (P < 0.04) and p70(S6K) (P < 0.001) and the dephosphorylation of eIF2alpha (P < 0.003) in the control group. Dexamethasone treatment did not alter the basal phosphorylation state of 4E-BP1, p70(S6K), or eIF2alpha; however, it abrogated the stimulatory effect of amino acid infusion on the phosphorylation of 4E-BP1 (P = 0.31) without affecting amino acid-induced phosphorylation of p70(S6K) (P = 0.002) or dephosphorylation of eIF2alpha (P = 0.003). Neither amino acid nor dexamethasone treatment altered the guanine nucleotide exchange activity of eIF2B. We conclude that changes of amino acid concentrations within the physiological range stimulate mRNA translation by enhancing the binding of mRNA to the 43S preinitiation complex, and the activity of p70(S6K) and glucocorticoid excess blocks the former action in vivo in human skeletal muscle.
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Affiliation(s)
- Zhenqi Liu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Virginia Health System, Charlottesville, VA 22908-1410, USA.
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Paddon-Jones D, Sheffield-Moore M, Zhang XJ, Volpi E, Wolf SE, Aarsland A, Ferrando AA, Wolfe RR. Amino acid ingestion improves muscle protein synthesis in the young and elderly. Am J Physiol Endocrinol Metab 2004; 286:E321-8. [PMID: 14583440 DOI: 10.1152/ajpendo.00368.2003] [Citation(s) in RCA: 310] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We recently demonstrated that muscle protein synthesis was stimulated to a similar extent in young and elderly subjects during a 3-h amino acid infusion. We sought to determine if a more practical bolus oral ingestion would also produce a similar response in young (34 +/- 4 yr) and elderly (67 +/- 2 yr) individuals. Arteriovenous blood samples and muscle biopsies were obtained during a primed (2.0 micromol/kg) constant infusion (0.05 micromol.kg(-1).min(-1)) of L-[ring-2H5]phenylalanine. Muscle protein kinetics and mixed muscle fractional synthetic rate (FSR) were calculated before and after the bolus ingestion of 15 g of essential amino acids (EAA) in young (n = 6) and elderly (n = 7) subjects. After EAA ingestion, the rate of increase in femoral artery phenylalanine concentration was slower in elderly subjects but remained elevated for a longer period. EAA ingestion increased FSR in both age groups by approximately 0.04%/h (P < 0.05). However, muscle intracellular (IC) phenylalanine concentration remained significantly higher in elderly subjects at the completion of the study (young: 115.6 +/- 5.4 nmol/ml; elderly: 150.2 +/- 19.4 nmol/ml). Correction for the free phenylalanine retained in the muscle IC pool resulted in similar net phenylalanine uptake values in the young and elderly. EAA ingestion increased plasma insulin levels in young (6.1 +/- 1.2 to 21.3 +/- 3.1 microIU/ml) but not in elderly subjects (3.0 +/- 0.6 to 4.3 +/- 0.4 microIU/ml). Despite differences in the time course of plasma phenylalanine kinetics and a greater residual IC phenylalanine concentration, amino acid supplementation acutely stimulated muscle protein synthesis in both young and elderly individuals.
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Affiliation(s)
- Douglas Paddon-Jones
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas 77550, USA.
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