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Ornstrup MJ, Høst C, Rittig N, Gravholt CH. Acute effects of testosterone on whole body protein metabolism in hypogonadal and eugonadal conditions: a randomized, placebo-controlled, crossover study. J Appl Physiol (1985) 2024; 136:1460-1467. [PMID: 38634506 DOI: 10.1152/japplphysiol.00078.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/19/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
Chronic testosterone (T) substitution and short-term T administration positively affect protein metabolism, however, data on acute effects in humans are sparse. This study aimed to investigate T's acute effects on whole body protein metabolism in hypogonadal and eugonadal conditions. We designed a randomized, double-blind, placebo-controlled, crossover study, including 12 healthy young males. Whole body protein metabolism was evaluated during 1) eugonadism, and after medically induced hypogonadism, with application of a gel on each trial day containing either 2) placebo, 3) T 50 mg, or 4) T 150 mg; under basal (5-h basal period) and insulin-stimulated conditions (3-h clamp). The main outcome measure was a change in net protein balance. The net protein loss was 62% larger in the placebo-treated hypogonadal state compared with the eugonadal state during the basal period (-5.5 ± 3.5 µmol/kg/h vs. -3.4 ± 1.2 µmol/kg/h, P = 0.038), but not during the clamp (P = 0.06). Also, hypogonadism resulted in a 25% increase in whole body urea flux (P = 0.006). However, T did not result in any significant changes in protein breakdown, synthesis, or net balance during either the basal period or clamp (all P > 0.05). Protein breakdown was reduced during clamp compared with the basal period regardless of gonadal status or T exposure (all P ≤ 0.001). In conclusion, the application of transdermal T did not counteract the negative effects of hypogonadism with no effects on protein metabolism within 5 h of administration. Insulin (during clamp) mitigated the effects of hypogonadism. This study is the first to investigate acute protein metabolic effects of T in hypogonadal men.NEW & NOTEWORTHY In a model of medically induced hypogonadism in male volunteers, we found increased whole body urea flux and net protein loss as an expected consequence of hypogonadism. Our study demonstrates the novel finding that the application of transdermal testosterone had no acute effects on whole body protein metabolism under eugonadal conditions, nor could it mitigate the hypogonadism-induced changes in protein metabolism. In contrast, insulin (during clamp) mitigated the effects of hypogonadism on protein metabolism.
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Affiliation(s)
- Marie Juul Ornstrup
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Christian Høst
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Nikolaj Rittig
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Claus H Gravholt
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
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Wilkinson DJ, Crossland H, Atherton PJ. Metabolomic and proteomic applications to exercise biomedicine. TRANSLATIONAL EXERCISE BIOMEDICINE 2024; 1:9-22. [PMID: 38660119 PMCID: PMC11036890 DOI: 10.1515/teb-2024-2006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/07/2024] [Indexed: 04/26/2024]
Abstract
Objectives 'OMICs encapsulates study of scaled data acquisition, at the levels of DNA, RNA, protein, and metabolite species. The broad objectives of OMICs in biomedical exercise research are multifarious, but commonly relate to biomarker development and understanding features of exercise adaptation in health, ageing and metabolic diseases. Methods This field is one of exponential technical (i.e., depth of feature coverage) and scientific (i.e., in health, metabolic conditions and ageing, multi-OMICs) progress adopting targeted and untargeted approaches. Results Key findings in exercise biomedicine have led to the identification of OMIC features linking to heritability or adaptive responses to exercise e.g., the forging of GWAS/proteome/metabolome links to cardiovascular fitness and metabolic health adaptations. The recent addition of stable isotope tracing to proteomics ('dynamic proteomics') and metabolomics ('fluxomics') represents the next phase of state-of-the-art in 'OMICS. Conclusions These methods overcome limitations associated with point-in-time 'OMICs and can be achieved using substrate-specific tracers or deuterium oxide (D2O), depending on the question; these methods could help identify how individual protein turnover and metabolite flux may explain exercise responses. We contend application of these methods will shed new light in translational exercise biomedicine.
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Affiliation(s)
- Daniel J. Wilkinson
- Centre of Metabolism, Ageing & Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Hannah Crossland
- Centre of Metabolism, Ageing & Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Philip J. Atherton
- Centre of Metabolism, Ageing & Physiology (CoMAP), Medical Research Council/Versus Arthritis UK Centre of Excellence for Musculoskeletal Ageing Research (CMAR), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
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Carpentier AC. Tracers and Imaging of Fatty Acid and Energy Metabolism of Human Adipose Tissues. Physiology (Bethesda) 2024; 39:0. [PMID: 38113392 DOI: 10.1152/physiol.00012.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/22/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023] Open
Abstract
White adipose tissue and brown adipose tissue (WAT and BAT) regulate fatty acid metabolism and control lipid fluxes to other organs. Dysfunction of these key metabolic processes contributes to organ insulin resistance and inflammation leading to chronic diseases such as type 2 diabetes, metabolic dysfunction-associated steatohepatitis, and cardiovascular diseases. Metabolic tracers combined with molecular imaging methods are powerful tools for the investigation of these pathogenic mechanisms. Herein, I review some of the positron emission tomography and magnetic resonance imaging methods combined with stable isotopic metabolic tracers to investigate fatty acid and energy metabolism, focusing on human WAT and BAT metabolism. I will discuss the complementary strengths offered by these methods for human investigations and current gaps in the field.
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Affiliation(s)
- André C Carpentier
- Department of Medicine, Division of Endocrinology, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Sarri L, Balcells J, Seradj AR, de la Fuente G. Protein turnover in pigs: A review of interacting factors. J Anim Physiol Anim Nutr (Berl) 2024; 108:451-469. [PMID: 37975299 DOI: 10.1111/jpn.13906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 08/24/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Protein turnover defines the balance between two continuous and complex processes of protein metabolism, synthesis and degradation, which determine their deposition in tissues. Although the liver and intestine have been studied extensively for their important roles in protein digestion, absorption and metabolism, the study of protein metabolism has focused mainly on skeletal muscle tissue to understand the basis for its growth. Due to the high adaptability of skeletal muscle, its protein turnover is greatly affected by different internal and external factors, contributing to carcass lean-yield and animal growth. Amino acid (AA) labelling and tracking using isotope tracer methodology, together with the study of myofiber type profiling, signal transduction pathways and gene expression, has allowed the analysis of these mechanisms from different perspectives. Positive stimuli such as increased nutrient availability in the diet (e.g., AA), physical activity, the presence of certain hormones (e.g., testosterone) or a more oxidative myofiber profile in certain muscles or pig genotypes promote increased upregulation of translation and transcription-related genes, activation of mTORC1 signalling mechanisms and increased abundance of satellite cells, allowing for more efficient protein synthesis. However, fasting, animal aging, inactivity and stress, inflammation or sepsis produce the opposite effect. Deepening the understanding of modifying factors and their possible interaction may contribute to the design of optimal strategies to better control tissue growth and nutrient use (i.e., protein and AA), and thus advance the precision feeding strategy.
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Affiliation(s)
- Laura Sarri
- Departament de Ciència Animal, Universitat de Lleida- Agrotecnio-CERCA Center, Lleida, Spain
| | - Joaquim Balcells
- Departament de Ciència Animal, Universitat de Lleida- Agrotecnio-CERCA Center, Lleida, Spain
| | - Ahmad Reza Seradj
- Departament de Ciència Animal, Universitat de Lleida- Agrotecnio-CERCA Center, Lleida, Spain
| | - Gabriel de la Fuente
- Departament de Ciència Animal, Universitat de Lleida- Agrotecnio-CERCA Center, Lleida, Spain
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Morgan PT, Witard OC, Højfeldt G, Church DD, Breen L. Dietary protein recommendations to support healthy muscle ageing in the 21st century and beyond: considerations and future directions. Proc Nutr Soc 2023:1-14. [PMID: 37818636 DOI: 10.1017/s0029665123003750] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
This review explores the evolution of dietary protein intake requirements and recommendations, with a focus on skeletal muscle remodelling to support healthy ageing based on presentations at the 2023 Nutrition Society summer conference. In this review, we describe the role of dietary protein for metabolic health and ageing muscle, explain the origins of protein and amino acid (AA) requirements and discuss current recommendations for dietary protein intake, which currently sits at about 0⋅8 g/kg/d. We also critique existing (e.g. nitrogen balance) and contemporary (e.g. indicator AA oxidation) methods to determine protein/AA intake requirements and suggest that existing methods may underestimate requirements, with more contemporary assessments indicating protein recommendations may need to be increased to >1⋅0 g/kg/d. One example of evolution in dietary protein guidance is the transition from protein requirements to recommendations. Hence, we discuss the refinement of protein/AA requirements for skeletal muscle maintenance with advanced age beyond simply the dose (e.g. source, type, quality, timing, pattern, nutrient co-ingestion) and explore the efficacy and sustainability of alternative protein sources beyond animal-based proteins to facilitate skeletal muscle remodelling in older age. We conclude that, whilst a growing body of research has demonstrated that animal-free protein sources can effectively stimulate and support muscle remodelling in a manner that is comparable to animal-based proteins, food systems need to sustainably provide a diversity of both plant and animal source foods, not least for their protein content but other vital nutrients. Finally, we propose some priority research directions for the field of protein nutrition and healthy ageing.
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Affiliation(s)
- Paul T Morgan
- Department of Sport and Exercise Sciences, Institute of Sport, Manchester Metropolitan University, 99 Oxford Road, Manchester M1 7EL, UK
| | - Oliver C Witard
- Centre for Human and Applied Physiological Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Grith Højfeldt
- Department of Orthopedic Surgery, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - David D Church
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Leigh Breen
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Fornasiero EF, Savas JN. Determining and interpreting protein lifetimes in mammalian tissues. Trends Biochem Sci 2023; 48:106-118. [PMID: 36163144 PMCID: PMC9868050 DOI: 10.1016/j.tibs.2022.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 01/26/2023]
Abstract
The orchestration of protein production and degradation, and the regulation of protein lifetimes, play a central role in the majority of biological processes. Recent advances in proteomics have enabled the estimation of protein half-lives for thousands of proteins in vivo. What is the utility of these measurements, and how can they be leveraged to interpret the proteome changes occurring during development, aging, and disease? This opinion article summarizes leading technical approaches and highlights their strengths and weaknesses. We also disambiguate frequently used terminology, illustrate recent mechanistic insights, and provide guidance for interpreting and validating protein turnover measurements. Overall, protein lifetimes, coupled to estimates of protein levels, are essential for obtaining a deep understanding of mammalian biology and the basic processes defining life itself.
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Affiliation(s)
- Eugenio F Fornasiero
- Department of Neuro-Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany.
| | - Jeffrey N Savas
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Wallace M. Metabolic balance-a masterclass in mass action. Nat Metab 2022; 4:17-18. [PMID: 35058632 DOI: 10.1038/s42255-021-00522-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Martina Wallace
- Institute of Food and Health, School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.
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Dietary protein requirements and recommendations for healthy older adults: a critical narrative review of the scientific evidence. Nutr Res Rev 2021; 36:69-85. [PMID: 34666855 DOI: 10.1017/s0954422421000329] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Adequate protein intake is essential for the maintenance of whole-body protein mass. Different methodological approaches are used to substantiate the evidence for the current protein recommendations, and it is continuously debated whether older adults require more protein to counteract the age-dependent loss of muscle mass, sarcopenia. Thus, the purpose of this critical narrative review is to outline and discuss differences in the approaches and methodologies assessing the protein requirements and, hence, resulting in controversies in current protein recommendations for healthy older adults. Through a literature search, this narrative review first summarises the historical development of the Food and Agriculture Organization/World Health Organization/United Nations University setting of protein requirements and recommendations for healthy older adults. Hereafter, we describe the various types of studies (epidemiological studies and protein turnover kinetic measurements) and applied methodological approaches founding the basis and the different recommendations with focus on healthy older adults. Finally, we discuss important factors to be considered in future studies to obtain evidence for international agreement on protein requirements and recommendations for healthy older adults. We conclude by proposing future directions to determine 'true' protein requirements and recommendations for healthy older adults.
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Nishimura Y, Musa I, Holm L, Lai YC. Recent advances in measuring and understanding the regulation of exercise-mediated protein degradation in skeletal muscle. Am J Physiol Cell Physiol 2021; 321:C276-C287. [PMID: 34038244 DOI: 10.1152/ajpcell.00115.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Skeletal muscle protein turnover plays a crucial role in controlling muscle mass and protein quality control, including sarcomeric (structural and contractile) proteins. Protein turnover is a dynamic and continual process of protein synthesis and degradation. The ubiquitin proteasome system (UPS) is a key degradative system for protein degradation and protein quality control in skeletal muscle. UPS-mediated protein quality control is known to be impaired in aging and diseases. Exercise is a well-recognized, nonpharmacological approach to promote muscle protein turnover rates. Over the past decades, we have acquired substantial knowledge of molecular mechanisms of muscle protein synthesis after exercise. However, there have been considerable gaps in the mechanisms of how muscle protein degradation is regulated at the molecular level. The main challenge to understand muscle protein degradation is due in part to the lack of solid stable isotope tracer methodology to measure muscle protein degradation rate. Understanding the mechanisms of UPS with the concomitant measurement of protein degradation rate in skeletal muscle will help identify novel therapeutic strategies to ameliorate impaired protein turnover and protein quality control in aging and diseases. Thus, the goal of this present review was to highlight how recent advances in the field may help improve our understanding of exercise-mediated protein degradation. We discuss 1) the emerging roles of protein phosphorylation and ubiquitylation modifications in regulating proteasome-mediated protein degradation after exercise and 2) methodological advances to measure in vivo myofibrillar protein degradation rate using stable isotope tracer methods.
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Affiliation(s)
- Yusuke Nishimura
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ibrahim Musa
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Lars Holm
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
| | - Yu-Chiang Lai
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, United Kingdom
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
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