MUSCLE DISUSE AS A PIVOTAL PROBLEM IN SARCOPENIA-RELATED MUSCLE LOSS AND DYSFUNCTION

2016 ◽  
pp. 1-9
Author(s):  
K.E. BELL ◽  
M.T. VON ALLMEN ◽  
M.C. DEVRIES ◽  
S.M. PHILLIPS
Keyword(s):  
Older Adults ◽  
Muscle Mass ◽  
Metabolic Diseases ◽  
Disease Risk ◽  
Bed Rest ◽  
Relative Reduction ◽  
Ambulatory Activity ◽  
Anabolic Resistance ◽  
Muscle Disuse ◽  
Increased Risk

An age-associated loss of muscle mass and strength – sarcopenia – begins at around the fifth decade of life, with mass being lost at ~0.5-1.2% per year and strength at ~3% per year. Sarcopenia can contribute to a variety of negative health outcomes, including an increased risk for falls and fractures, the development of metabolic diseases like type 2 diabetes mellitus, and increase the chance of requiring assisted living. Linear sarcopenic declines in muscle mass and strength are, however, punctuated by transient periods of muscle disuse that can accelerate losses of muscle and strength, which could result in increased risk for the aforementioned conditions. Muscle disuse is recognizable with bed rest or immobilization (for example, due to surgery or acute illness requiring hospitalization); however, recent work has shown that even a relative reduction in ambulation (reduced daily steps) results in significant reductions in muscle mass, strength and possibly an increase in disease risk. Although reduced ambulation is a seemingly “benign” form of disuse, compared to bed rest and immobilization, reports have documented that 2-3 weeks of reduced daily steps may induce: negative changes in body composition, reductions in muscle strength and quality, anabolic resistance, and decrements in glycemic control in older adults. Importantly, periods of reduced ambulation likely occur fairly frequently and appear more difficult to fully recover from, in older adults. Here we explore the consequences of muscle disuse due to reduced ambulatory activity in older adults, with frequent comparisons to established models of disuse: bed rest and immobilization.

scholarly journals Lower Skeletal Muscle Mass at Admission Independently Predicts Falls and Mortality 3 Months Post-discharge in Hospitalized Older Patients

2018 ◽  
Vol 74 (10) ◽  
pp. 1650-1656 ◽  
Author(s):  
Esmee M Reijnierse ◽  
Sjors Verlaan ◽  
Vivien K Pham ◽  
Wen Kwang Lim ◽  
Carel G M Meskers ◽  
...  
Keyword(s):  
Older Adults ◽  
Cognitive Impairment ◽  
Muscle Mass ◽  
Older Patients ◽  
Test Score ◽  
Handgrip Strength ◽  
Bed Rest ◽  
Post Discharge ◽  
Male Sex ◽  
Prospective Longitudinal

Abstract Background Approximately 10% of older adults are annually admitted to a hospital. Hospitalization is associated with a higher risk of falls and mortality after discharge. This study aimed to identify predictors at admission for falls and mortality 3 months post-discharge in hospitalized older patients. Methods The Evaluation of Muscle parameters in a Prospective cohort of Older patients at clinical Wards Exploring Relations with bed rest and malnutrition (EMPOWER) study is an observational, prospective longitudinal inception cohort of 378 patients aged 70 years and older who were subsequently admitted to a tertiary hospital (the Netherlands). Potential predictors for falls and mortality 3 months post-discharge were tested using univariate and multivariate logistic regression analyses and included the following domains: demographic (age, sex, living independently), lifestyle (alcohol, smoking), nutrition (SNAQ score), muscle mass (absolute, relative), physical function (handgrip strength, Katz ADL score), cognition (six-item cognitive impairment test score), and disease (medications, diseases). Results The mean age was 79.6 years (standard deviation 6.23) and 50% were male. Within 3 months post-discharge, 19% reported a fall and 13% deceased. Univariate predictors for falls were higher age, lower absolute muscle mass and higher six-item cognitive impairment test score. Lower absolute muscle mass independently predicted falls post-discharge (multivariate). Univariate predictors for mortality were higher age, male sex, no current alcohol use, higher SNAQ score, lower absolute and higher relative muscle mass, higher Katz ADL score and higher number of diseases. Male sex, higher SNAQ score, and lower absolute muscle mass independently predicted mortality post-discharge (multivariate). Conclusions In hospitalized older adults, muscle mass should be measured to predict future outcome. Future intervention studies should investigate if increasing muscle mass prevent short-term falls and mortality.

scholarly journals Adipose tissue: from amorphous filler to metabolic mastermind

2021 ◽  
Author(s):  
Silvia Corvera
Keyword(s):  
Adipose Tissue ◽  
Metabolic Diseases ◽  
Disease Risk ◽  
Appetite Control ◽  
Fat Storage ◽  
Fuel Distribution ◽  
Adipose Tissue Depots ◽  
Increased Risk ◽  
Adipocyte Hypertrophy ◽  
Adipocyte Hyperplasia

Adipose tissue plays a central role in the control of systemic glucose homeostasis through two major mechanisms: fat storage and secretion of specific cytokines known as adipokines. Fat storage in adipose tissue is critically important, as it prevents lipid deposition in liver and muscle, which in turn results in insulin resistance and increased risk of type 2 diabetes. Secretion of adipokines, such as leptin, protects from fuel depletion through appetite control, and other adipokines control fuel distribution and utilization. Fat storage capacity of adipose tissue increases through two mechanisms, adipocyte hypertrophy and adipocyte hyperplasia. Adipose tissue depots expand differently in diverse individuals and confer varying degrees of metabolic disease risk. There are multiple adipocyte subtypes that together mediate the functions of adipose tissue. They do so through specialized functions such as thermogenesis, which burns fuel to maintain core temperature, and through selective secretion of different adipokines. Much progress has been made in understanding the mechanisms by which adipose tissue controls systemic metabolism, increasing our hope of developing new, effective therapies for metabolic diseases.

scholarly journals Leucine Supplementation Partially Protects Leg Lean Mass in Older Adults During Seven Days of Bed Rest (OR18-02-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Emily Arentson-Lantz ◽  
Fego Galvan ◽  
Rachel Deer ◽  
Adam Wacher ◽  
Doug Paddon-Jones
Keyword(s):  
Older Adults ◽  
Clinical Research ◽  
Muscle Fiber ◽  
Lean Mass ◽  
Fiber Type ◽  
Bed Rest ◽  
Research Center ◽  
Leucine Supplementation ◽  
Clinical Research Center ◽  
Increased Risk

Abstract Objectives Older adults are at increased risk of being hospitalized or bedridden and experiencing a host of negative health outcomes including loss of lean body mass. We hypothesized that supplementing daily meals with a small quantity (3–4 g/meal) of leucine will partially preserve lean leg mass and function during bed rest. Methods Men and women (67.8 ± 1.1 y) were randomized to receive isoenergentic meals supplemented with leucine (LEU, 0.06 g/kg/meal; n = 10) or an alanine control, (CON, 0.06 g/kg/meal; n = 10). Subjects were admitted to the Clinical Research Center for 7 days of bed rest followed by 7 days of rehabilitation. Muscle fiber type and cross-sectional area (CSA) as well as single fiber characteristics were assessed from biopsies of the vastus lateralis obtained prior to (Pre-BR) and after bed rest (Post-BR) and after rehabilitation (Post-RE). Body composition measured using iDEXA was also determined at the same time points. Results Leucine-supplementation partially protected leg lean mass during bed rest (−1035 vs. −423 ± 143 g; P = 0.008). Leg lean mass did not differ between the groups Post-RE (P = 0.16). There was no significant effect of time (P = 0.16) or treatment (P = 0.92) on muscle fiber CSA; however, CON subjects, but not LEU subjects, exhibited an increased number of smaller fibers (<2000 um) and fewer larger fibers (>6000 um) Post-BR. Additionally, CON subjects tended to have a greater decrement in fiber width (P = 0.085) that did not return to baseline following rehabilitation. Conclusions Supplementing older adults with moderate amounts of leucine has the potential to partially negate some of the deleterious effects on muscle health during short bouts of inactivity. Funding Sources National Institutes of Health, The Claude D. Pepper Older Americans Independence Center, Sealy Center on Aging and Institute for Translational Sciences-Clinical Research Center.

scholarly journals Comparison of methods to identify individuals with obesity at increased risk of functional impairment among a population of home-dwelling older adults

2021 ◽  
pp. 1-8
Author(s):  
Anne Lene Nordengen ◽  
Linn Kristin Lie Øyri ◽  
Stine Marie Ulven ◽  
Truls Raastad ◽  
Kirsten Bjørklund Holven ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Strength ◽  
Muscle Mass ◽  
Body Mass ◽  
Functional Impairment ◽  
Muscle Quality ◽  
Obese Women ◽  
Total Body Mass ◽  
Increased Risk ◽  
Total Body

Abstract Obesity is associated with increased muscle mass and muscle strength. Methods taking into account the total body mass to reveal obese older individuals at increased risk of functional impairment are needed. Therefore, we aimed to detect methods to identify obese older adults at increased risk of functional impairment. Home-dwelling older adults (n 417, ≥ 70 years of age) were included in this cross-sectional study. Sex-specific cut-off points for two obesity phenotypes (waist circumference (WC) and body fat mass (FM %)) were used to divide women and men into obese and non-obese groups, and within-sex comparisons were performed. Obese women and men, classified by both phenotypes, had similar absolute handgrip strength (HGS) but lower relative HGS (HGS/total body mass) (P < 0·001) than non-obese women and men, respectively. Women with increased WC and FM %, and men with increased WC had higher appendicular skeletal muscle mass (P < 0·001), lower muscle quality (HGS/upper appendicular muscle mass) (P < 0·001), and spent longer time on the stair climb test and the repeated sit-to-stand test (P < 0·05) than non-obese women and men, respectively. Absolute muscle strength was not able to discriminate between obese and non-obese older adults. However, relative muscle strength in particular, but also muscle quality and physical performance tests, where the total body mass was taken into account or served as an extra load, identified obese older adults at increased risk of functional impairment. Prospective studies are needed to determine clinically relevant cut-off points for relative HGS in particular.

Dietary protein considerations for muscle protein synthesis and muscle mass preservation in older adults

2020 ◽  
pp. 1-11 ◽  
Author(s):  
Eunice T. Olaniyan ◽  
Fiona O’Halloran ◽  
Aoife L. McCarthy
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adult Population ◽  
Anabolic Resistance

Abstract Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.

FISH OILS AND THEIR POTENTIAL IN THE TREATMENT OF SARCOPENIA

2013 ◽  
pp. 1-6
Author(s):  
S.R. GRAY ◽  
M. DA BOIT
Keyword(s):  
Fish Oil ◽  
Muscle Mass ◽  
Health Problems ◽  
Fish Oils ◽  
Ageing Society ◽  
Anabolic Resistance ◽  
Nutritional Interventions ◽  
Increased Risk ◽  
Risk Of Falls ◽  
Nutritional Strategies

We are living in an “ageing society” meaning that there will be an increase in the incidence of agerelated health problems. One issue consistently observed in ageing is for muscle mass and strength to be reduced,a condition termed sarcopenia. The consequences of these changes are numerous and include a reduction inquality of life and an increased risk of falls. The mechanisms underlying sarcopenia remain to be elucidated butinclude an anabolic resistance to both nutrients and exercise and so the search for strategies to overcome thisresistance is of great importance. There are several nutritional strategies purported to be useful in the treatment ofsarcopenia and in recent years the n-3 PUFAs found in fish oil have been of increasing interest. This review willdiscuss the main nutritional interventions used in the treatment of sarcopenia with a focus on fish oils.

scholarly journals Anabolic resistance assessed by oral stable isotope ingestion following bed rest in young and older adult volunteers: Relationships with changes in muscle mass

2017 ◽  
Vol 36 (5) ◽  
pp. 1420-1426 ◽  
Author(s):  
Gianni Biolo ◽  
Rado Pišot ◽  
Sara Mazzucco ◽  
Filippo Giorgio Di Girolamo ◽  
Roberta Situlin ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Muscle Mass ◽  
Older Adult ◽  
Bed Rest ◽  
Anabolic Resistance ◽  
Adult Volunteers

scholarly journals Countering disuse atrophy in older adults with low-volume leucine supplementation

2020 ◽  
Vol 128 (4) ◽  
pp. 967-977 ◽  
Author(s):  
Emily J. Arentson-Lantz ◽  
Kinga N. Fiebig ◽  
Kim J. Anderson-Catania ◽  
Rachel R. Deer ◽  
Adam Wacher ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Fiber ◽  
Functional Capacity ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Bed Rest ◽  
Single Fiber ◽  
Leucine Supplementation ◽  
Increased Risk ◽  
And Function

Older adults are at increased risk of being bedridden and experiencing negative health outcomes including the loss of muscle tissue and functional capacity. We hypothesized that supplementing daily meals with a small quantity (3–4 g/meal) of leucine would partially preserve lean leg mass and function of older adults during bed rest. During a 7-day bed rest protocol, followed by 5 days of inpatient rehabilitation, healthy older men and women (67.8 ± 1.1 yr, 14 men; 6 women) were randomized to receive isoenergetic meals supplemented with leucine (LEU, 0.06 g/kg/meal; n = 10) or an alanine control (CON, 0.06 g/kg/meal; n = 10). Outcomes were assessed at baseline, following bed rest, and after rehabilitation. Body composition was measured by dual-energy X-ray absorptiometry. Functional capacity was assessed by knee extensor isokinetic and isometric dynamometry, peak aerobic capacity, and the short physical performance battery. Muscle fiber type, cross-sectional area, signaling protein expression levels, and single fiber characteristics were determined from biopsies of the vastus lateralis. Leucine supplementation reduced the loss of leg lean mass during bed rest (LEU vs. CON: −423 vs. −1035 ± 143 g; P = 0.008) but had limited impact on strength or endurance-based functional outcomes. Similarly, leucine had no effect on markers of anabolic signaling and protein degradation during bed rest or rehabilitation. In conclusion, providing older adults with supplemental leucine has minimal impact on total energy or protein consumption and has the potential to partially counter some, but not all, of the negative effects of inactivity on muscle health. NEW & NOTEWORTHY Skeletal muscle morphology and function in older adults was significantly compromised by 7 days of disuse. Leucine supplementation partially countered the loss of lean leg mass but did not preserve muscle function or positively impact changes at the muscle fiber level associated with bed rest or rehabilitation. Of note, our data support a relationship between myonuclear content and adaptations to muscle atrophy at the whole limb and single fiber level.

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