Target population for clinical trials on sarcopenia

Sex-specific microbiota associations with backfat thickness, eye muscle area, and rumen fermentation in Qinchuan cattle

BACKGROUND

Ruminant livestock are essential for global food production, and understanding sex-specific rumen fermentation and microbial differences is key to improving production efficiency and meat quality. This study explored sex-specific variations in backfat thickness, eye muscle area, rumen fermentation, and microbiota in Qinchuan cattle.

RESULTS

The results revealed that heifers exhibited higher backfat thickness, butyrate concentrations, and acetate/propionate ratio, whereas bulls had larger eye muscle areas and higher propionate concentrations. Volatile fatty acids (VFAs) transport-related genes (CA4, DRA, and NHE1) were more highly expressed in bulls. Heifers showed greater microbial diversity with distinct sex-specific community structures. Bulls had a higher abundance of Prevotella, while butyrate-producing bacteria like Butyrivibrio and Pseudobutyrivibrio were more abundant in heifers. Functional predictions revealed that bulls were enriched in glycan biosynthesis and amino acid metabolism pathways, whereas heifers showed enhanced lipid metabolism pathways. Correlation analyses showed that backfat thickness was positively correlated with acetate and butyrate production, and acetate/propionate ratio, but negatively correlated with Veillonellaceae_UCG-001. Eye muscle area was negatively correlated with isobutyrate production and the abundance of Elusimicrobium and Anaeroplasma, but positively correlated with Lachnospiraceae_NK3A20_group. Redundancy analysis (RDA) identified propionate and butyrate as key drivers of microbial community differences. The Random Forest model identified key predictors for backfat thickness, including rumen fermentation parameters, microbial taxa, and metabolic pathways, explaining 28% of the variation. However, eye muscle area was not well predicted by the current parameters.

CONCLUSION

These findings enhance our understanding of sex-specific microbial and metabolic profiles, offering potential strategies for optimizing livestock management and breeding programs.

Cross-Sectional Associations Between Dietary Antioxidant Vitamins C, E and Carotenoid Intakes and Sarcopenic Indices in Women Aged 18-79 Years

The prevalence of sarcopenia is increasing in aging populations, so prevention is critical. Vitamins (A, C, E and carotenoids) modify skeletal muscle via protein and collagen synthesis and anti-inflammatory activities. Previous studies have not investigated intake of these vitamins in relation to sarcopenic indices in both younger and older-aged women. Indices of skeletal muscle mass (as fat-free mass (FFM) relative to body size) were measured using DXA and leg explosive power (LEP) using the Nottingham Power Rig in 2570 women aged 18-79 years. Adjusted measures of skeletal muscle were calculated according to quintiles of vitamin C, E, retinol and carotenoid intake, derived from Food Frequency Questionnaires, after stratification by age. Higher vitamin C intake was associated with significantly higher indices of FFM and LEP, (Q5-Q1 = 2.0-12.8%, P < 0.01-0.02). Intakes of total and individual carotenoids were significantly associated with indices of FFM and LEP (Q5-Q1 = 1.0-7.5%). Vitamin E was significantly associated with FFM% and FFM_BMI only. In mutually adjusted analysis with vitamin C, total carotene, vitamin E and protein in the model, the strongest associations were with vitamin C. These associations were stronger in younger women (< 65 years). For the first time, our research shows higher dietary intakes of antioxidant vitamins, particularly vitamin C, is associated with higher skeletal muscle mass and power in free-living women. These findings have relevance for the treatment and prevention of frailty and sarcopenia throughout adulthood.

Axial Muscle Size as a Strong Predictor of Death in Subjects With and Without Heart Failure

Background

The impact of skeletal muscle size, quantified using simple noninvasive images routinely obtained during cardiac magnetic resonance imaging studies on mortality in the heart failure (HF) population is currently unknown.

Methods and Results

We prospectively enrolled 567 subjects without HF (n=364), with HF with reduced ejection fraction (n=111), or with HF with preserved ejection fraction (n=92), who underwent a cardiac magnetic resonance imaging. Skeletal muscle cross‐sectional area was assessed with manual tracing of major thoracic muscle groups on axial chest magnetic resonance images. Factor analysis was used to identify a latent factor underlying the shared variability in thoracic muscle cross‐sectional area. Cox regression was used to assess the relationship between these measurements and all‐cause mortality (median follow up, 36.4 months). A higher overall thoracic muscle area factor assessed with principal component analysis was independently associated with lower mortality (standardized hazard ratio, 0.51; P<0.0001). The thoracic muscle area factor was predictive of death in subjects with HF with preserved ejection fraction, HF with reduced ejection fraction, and those without HF. Among all muscle groups, the pectoralis major cross‐sectional area was the most representative of overall muscle area and was also the most robust predictor of death. A higher pectoralis major cross‐sectional area predicted a lower mortality (standardized hazard ratio, 0.49; P<0.0001), which persisted after adjustment for various confounders (standardized hazard ratio, 0.55; P=0.0017).

Conclusions

Axial muscle size, and in particular smaller size of the pectoralis major, is independently associated with higher risk of mortality in patients with and without HF. Further work should clarify the role of muscle wasting as a therapeutic target in patients with HF.

Serum Albumin Is a Marker of Myocardial Fibrosis, Adverse Pulsatile Aortic Hemodynamics, and Prognosis in Heart Failure With Preserved Ejection Fraction

Background

Data regarding the phenotypic correlates and prognostic value of albumin in heart failure with preserved ejection fraction (HFpEF) are scarce. The goal of the current study is to determine phenotypic correlates (myocardial hypertrophy, myocardial fibrosis, detailed pulsatile hemodynamics, and skeletal muscle mass) and prognostic implications of serum albumin in HFpEF.

Methods and Results

We studied 118 adults with HFpEF. All‐cause death or heart‐failure–related hospitalization was ascertained over a median follow‐up of 57.6 months. We measured left ventricular mass, myocardial extracellular volume, and axial muscle areas using magnetic resonance imaging. Pulsatile arterial hemodynamics were assessed with a combination of arterial tonometry and phase‐contrast magnetic resonance imaging. Subjects with lower serum albumin exhibited a higher body mass index, and a greater proportion of black ethnicity and diabetes mellitus. A low serum albumin was associated with higher myocardial extracellular volume (52.3 versus 57.4 versus 39.3 mL in lowest to highest albumin tertile, respectively; P=0.0023) and greater N‐terminal pro B‐type natriuretic peptide levels, but not with a higher myocardial cellular volume (123 versus 114 versus 102 mL; P=0.13). Lower serum albumin was also associated with an increased forward wave amplitude and markedly increased pulsatile power in the aorta. Serum albumin was a strong predictor of death or heart failure hospitalization even after adjustment for N‐terminal pro B‐type natriuretic peptide levels and the Meta‐Analysis Global Group in Chronic Heart Failure (MAGGIC) risk score (adjusted standardized hazard ratio=0.56; 95% CI=0.37–0.83; P<0.0001).

Conclusions

Serum albumin is associated with myocardial fibrosis, adverse pulsatile aortic hemodynamics, and prognosis in HFpEF. This readily available clinical biomarker can enhance risk stratification in HFpEF and identifies a subgroup with specific pathophysiological abnormalities.

Health status, health behaviors, and the ability to perform everyday activities in Poles aged ≥65 years staying in their home environment

Background

The incidence of chronic diseases increases with age; about 73% of people who are aged ≥60 years suffer from at least 1 chronic disease, and among those older than 70 years, chronic diseases afflict more than >84% of the population. According to epidemiological data, at least 4 chronic disease types coexist in senior citizens, causing their disability. These are mainly cardiovascular diseases; motor system diseases; ophthalmological, auditory, neurological, and mental diseases; and mental impairment. They worsen or limit self-dependence in everyday activities. The process begins with complex activities and advances with age. At first, functional performance deficits are discreet; then, they may gradually lead to complete dependence on other people or institutions.

Objective

This study aimed to assess the relationship between diseases and health behaviors, as well as the everyday functioning of people aged ≥65 years staying in their home environment.

Methods

The research involved 504 elderly people. The inclusion criteria were age (≥65 years) and staying in one's own home environment. The direct interview technique was applied, as well as use of proprietary interview questionnaire and standardized tools used in geriatrics: Barthel scale, measuring performance in everyday activities, and the Instrumental Activities of Daily Living scale, assessing complex everyday activities.

Results

The most frequent disease among the responders was arterial hypertension (77.58%), followed by degenerative joint disease (62.10%), and circulatory failure (43.23%). Lower functional performance was associated with circulatory failure, cerebral stroke, atherosclerosis, Alzheimer's disease, diabetes, Parkinson's disease, degenerative joint disease, and bronchial asthma. Performance worsening significantly influenced the frequency of hospitalizations, with a mean score of 4.31 per person. Medical rehabilitation was practiced by 18.65% of the responders.

Conclusion

Circulatory failure, cerebral stroke, atherosclerosis, bronchial asthma, diabetes, degenerative joint disease, Parkinson's disease, and Alzheimer's disease negatively affect functional performance in elderly people. Hospitalization rates increase with lowering independence in everyday functioning. Future research is needed with regard to the relationship between the practiced rehabilitation and independence in everyday functioning of the elderly.

Sarcopenia in patients with heart failure with preserved ejection fraction: Impact on muscle strength, exercise capacity and quality of life

BACKGROUND

To describe the prevalence of sarcopenia in ambulatory patients with heart failure with preserved ejection fraction (HFpEF) and its relation to reduced exercise capacity, muscle strength, and quality of life (QoL).

METHODS AND RESULTS

A total of 117 symptomatic outpatients with HFpEF were prospectively enrolled in Germany, England, and Slovenia as part of the Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF). Appendicular skeletal muscle (ASM) mass (the sum of muscle mass in both arms and legs) was assessed by DEXA. Echocardiography, 6-minute walk testing (6-MWT), muscle strength assessment, spiroergometry and QoL evaluation using EQ-5D Questionnaire were performed. Sarcopenia was defined as ASM 2 standard deviations below the mean of a healthy reference group aged 18-40years. Patients were divided into 3 groups according to the E/e' value: ≤8, 9-14, and ≥15. Sarcopenia was detected in 19.7% of all patients. These patients performed worse during 6-MWT (404±116 vs. 307±145m, p=0.003) and showed lower absolute peak oxygen consumption (1579±474 vs. 1211±442mL/min, p<0.05). Both ASM and muscle strength were lowest in patients with E/e' >15 (p<0.05). Higher values of muscle strength/ASM were associated with a better QoL (r=0.5, p<0.0005). Logistic regression showed ASM to be independently associated with reduced distance walked during the 6-MWT adjusted for NYHA, height, left atrium diameter, ferritin and forced expiratory volume in 1s (FEV1) (odds ratio 1.2, p=0.02).

CONCLUSION

Sarcopenia affects a clinically relevant proportion of patients with HFpEF. Low ASM is strongly linked to reduced muscle strength, exercise capacity and QoL in these patients.

Sarcopenic obesity and the pathogenesis of exercise intolerance in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults. The primary chronic symptom in patients with HFpEF, even when well compensated, is severe exercise intolerance. Cardiac and peripheral functions contribute equally to exercise intolerance in HFpEF, though the latter has been the focus of fewer studies. Of note, multiple studies with exercise training have shown that exercise intolerance can improve significantly in the absence of improvements in exercise cardiac output, indicating a role of peripheral, noncardiac adaptations. In addition, clinical drug trials performed to date in HFpEF, all of which have focused on influencing cardiovascular function, have not been positive on primary clinical outcomes and most have not improved exercise capacity. Mounting evidence indicates that sarcopenic obesity, characterized by the coexistence of excess fat mass and decreased muscle mass, could contribute to the pathophysiology of exercise intolerance in older HFpEF patients and may provide avenues for novel treatments.

Exercise attenuates the major hallmarks of aging

Regular exercise has multi-system anti-aging effects. Here we summarize how exercise impacts the major hallmarks of aging. We propose that, besides searching for novel pharmaceutical targets of the aging process, more research efforts should be devoted to gaining insights into the molecular mediators of the benefits of exercise and to implement effective exercise interventions for elderly people.

Obesity in the Context of Aging: Quality of Life Considerations

The progressive increase in the prevalence of obesity and aging in the population is resulting in increased healthcare and disability spending. The burden of obesity is particularly relevant in old age, due to accumulating co-morbidities and changes in body composition. Sarcopenic obesity, a mix of over- and under-nutrition, causes frailty, disability, and problems in social and psychological areas, impacting overall health-related quality of life (HR-QOL). The relationship between obesity, aging, and HR-QOL is, however, much more complex than generally acknowledged and is difficult to disentangle. The impact of obesity on HR-QOL is particularly strong in young people, who are free of co-morbidities. It progressively attenuates, compared with the general population, with advancing age, when co-morbid conditions are diffusely present and reduce the perceived health status, independent of obesity. However, even this apparent 'obesity paradox' should not minimize the importance of obesity on HR-QOL, as other obesity-associated limitations and disabilities do impact HR-QOL in older age. A patient-centered approach aimed at reducing the disability and social isolation of advancing age is mandatory to improve HR-QOL in any class of obesity.

Relation Between Cigarette Smoking and Sarcopenia: Meta-Analysis

Cigarette smoking is a risk factor for many diseases. It could be associated with sarcopenia. The aim of this meta-analysis was to determine whether smoking is an isolated risk factor for sarcopenia. We searched PubMed, Web of Science, EBSCO, and Science Direct for articles addressing the relationship between cigarette smoking and sarcopenia. A total of 12 studies containing information on 22,515 participants were included in this meta-analysis. Odds ratio (OR) was calculated for each study group and for all studies together. An OR was also calculated separately for each sex. We used a fixed-effect model in overall estimation and in males, because results of small studies were significantly different from the results of large studies in those cases and in females where the estimation showed only moderate heterogeneity we used a random-effect model. According to proposes of the Cochrane Handbook for Systematic Reviews. The resulting OR in the fixed-effect model was 1.12 (95 % CI 1.03-1.21), OR for each sex was in the fixed-effect model 1.20 (95 % CI 1.06-1.35) in males and in the random-effect model 1.21 (95 % CI 0.92-1.59) in females. The results of this meta-analysis indicate that cigarette smoking as an isolated factor may contribute to the development of sarcopenia. However, the results of the individual studies were largely inconsistent due to different approaches of measuring the main variables which affected the results.

Mitochondrial dysfunction and sarcopenia of aging: from signaling pathways to clinical trials

Sarcopenia, the age-related loss of muscle mass and function, imposes a dramatic burden on individuals and society. The development of preventive and therapeutic strategies against sarcopenia is therefore perceived as an urgent need by health professionals and has instigated intensive research on the pathophysiology of this syndrome. The pathogenesis of sarcopenia is multifaceted and encompasses lifestyle habits, systemic factors (e.g., chronic inflammation and hormonal alterations), local environment perturbations (e.g., vascular dysfunction), and intramuscular specific processes. In this scenario, derangements in skeletal myocyte mitochondrial function are recognized as major factors contributing to the age-dependent muscle degeneration. In this review, we summarize prominent findings and controversial issues on the contribution of specific mitochondrial processes - including oxidative stress, quality control mechanisms and apoptotic signaling - on the development of sarcopenia. Extramuscular alterations accompanying the aging process with a potential impact on myocyte mitochondrial function are also discussed. We conclude with presenting methodological and safety considerations for the design of clinical trials targeting mitochondrial dysfunction to treat sarcopenia. Special emphasis is placed on the importance of monitoring the effects of an intervention on muscle mitochondrial function and identifying the optimal target population for the trial. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

Development of a practical screening tool to predict low muscle mass using NHANES 1999-2004

BACKGROUND

Skeletal muscle mass declines after the age of 50. Loss of skeletal muscle mass is associated with increased morbidity and mortality.

OBJECTIVE

This study aims to identify predictors of low skeletal muscle mass in older adults toward development of a practical clinical assessment tool for use by clinicians to identify patients requiring dual-energy X-ray absorptiometry (DXA) screening for muscle mass.

METHODS

Data were drawn from the National Health and Nutrition Examination Surveys (NHANES) from 1999 to 2004. Appendicular skeletal mass (ASM) was calculated based on DXA scans. Skeletal muscle mass index (SMI) was defined as the ratio of ASM divided by height in square centimeters. Elderly participants were classified as having low muscle mass if the SMI was 1 standard deviation (SD) below the mean SMI of young adults (20-40 years old). Logistic regression was conducted separately in males and females age ≥65 years of age to examine the relationship between patients identified as having low muscle mass and health behavior characteristics, adjusting for comorbid conditions. The model was validated on a separate sample of 200 patients.

RESULTS

Among the NHANES study population, 551 (39.7 %) males and 374 (27.5 %) females had a SMI below the 1 SD cutoff point. NHANES study subjects with a low SMI were older (mean age, 76.2 vs. 72.7 for male; 76.0 vs. 73.7 for female; and both p < 0.0001) and had a lower body mass index (mean BMI, 24.1 vs. 29.4 for male; 22.9 vs. 29.7 for female; p < 0.0001). In adjusted logistic regression analyses, age (for males) and BMI (for both males and females) remained statistically significant. A parsimonious logistic regression model adjusting for age and BMI only had a C statistic of 0.89 for both males and females. The discriminatory power of the parsimonious model increased to 0.93 for males and 0.95 for females when the cutoff defining low SMI was set to 2 SD below the SMI of young adults. In the validation sample, the sensitivity was 81.6 % for males and 90.6 % for females. The specificity was 66.2 % for males and females.

CONCLUSIONS

BMI was strongly associated with a low SMI and may be an informative predictor in the primary care setting. The predictive model worked well in a validation sample.

Genes and the ageing muscle: a review on genetic association studies

Western populations are living longer. Ageing decline in muscle mass and strength (i.e. sarcopenia) is becoming a growing public health problem, as it contributes to the decreased capacity for independent living. It is thus important to determine those genetic factors that interact with ageing and thus modulate functional capacity and skeletal muscle phenotypes in older people. It would be also clinically relevant to identify 'unfavourable' genotypes associated with accelerated sarcopenia. In this review, we summarized published information on the potential associations between some genetic polymorphisms and muscle phenotypes in older people. A special emphasis was placed on those candidate polymorphisms that have been more extensively studied, i.e. angiotensin-converting enzyme (ACE) gene I/D, α-actinin-3 (ACTN3) R577X, and myostatin (MSTN) K153R, among others. Although previous heritability studies have indicated that there is an important genetic contribution to individual variability in muscle phenotypes among old people, published data on specific gene variants are controversial. The ACTN3 R577X polymorphism could influence muscle function in old women, yet there is controversy with regards to which allele (R or X) might play a 'favourable' role. Though more research is needed, up-to-date MSTN genotype is possibly the strongest candidate to explain variance among muscle phenotypes in the elderly. Future studies should take into account the association between muscle phenotypes in this population and complex gene-gene and gene-environment interactions.

Genes, physical fitness and ageing

Persons aged 80 years and older are the fastest growing segment of the population. As more individuals live longer, we should try to understand the mechanisms involved in healthy ageing and preserving functional independence in later life. In elderly people, functional independence is directly dependent on physical fitness, and ageing is inevitably associated with the declining functions of systems and organs (heart, lungs, blood vessels, skeletal muscles) that determine physical fitness. Thus, age-related diminished physical fitness contributes to the development of sarcopenia, frailty or disability, all of which severely deteriorate independent living and thus quality of life. Ageing is a complex process involving many variables that interact with one another, including - besides lifestyle factors or chronic diseases - genetics. Thus, several studies have examined the contribution of genetic endowment to a decline in physical fitness and subsequent loss of independence in later life. In this review, we compile information, including data from heritability, candidate-gene association, linkage and genome-wide association studies, on genetic factors that could influence physical fitness in the elderly.

Sarcopenia and obesity

Four body composition phenotypes exist in older adults: normal, sarcopenic, obese, and a combination of sarcopenic and obese. There is no consensus, however, on the definitions and classifications of these phenotypes and their etiology and consequences continue to be debated. The lack of standard definitions, particularly for sarcopenia and sarcopenic obesity, creates challenges for determining prevalence across different populations. The etiology of these phenotypes is multifactorial with complex covariate relationships. This review focuses on the current literature addressing the classification, prevalence, etiology, and correlates of sarcopenia, obesity, and the combination of sarcopenia and obesity, referred to as sarcopenic obesity.

Designing Phase II B trials in sarcopenia: the best target population

Despite the existing limitations and controversies regarding the definition of sarcopenia and its clinical consequences, the current scientific evidence strongly suggests that muscle decline is a primary determinant of the disabling process (and likely of other major health-related events). In fact, the muscle loss (in terms of mass as well as strength) occurring with aging has been growingly associated with mobility impairment and disability in older persons. Unfortunately, current evidence is mainly from observational studies. Times are mature to begin testing interventions aimed at modifying the sarcopenia process through the design and development of specific clinical trials. Considering the emergence of many promising interventions towards this age-related condition (e.g., physical exercise [in particular, resistance training], testosterone, antioxidant supplementations), the need for Phase II trial designs is high. In the present report, we discuss which are the major issues related to the design of Phase II clinical trials on sarcopenia with particular focus on the participant's characteristics to be considered as possible inclusion and exclusion criteria.

Sarcopenia: designing phase IIB trials

Sarcopenia is the age-related involuntary loss of skeletal muscle mass and functionality that can lead to the development of disability, frailty and increased health care costs. The development of interventions aimed at preventing and/or treating sarcopenia is complex, requiring the adoption of assumptions and standards that are not well established scientifically or clinically. A number of investigators and clinicians (both from academia and industry) met in Rome (Italy) in 2009 to develop a consensus definition of sarcopenia. Subsequently, in Albuquerque (New Mexico, USA) in 2010, the same group met again to consider the complex issues necessary for designing Phase II clinical trials for sarcopenia. Current clinical trial data indicate that fat-free mass (FFM) parameters are responsive to physical activity/nutritional treatment modalities over short time periods, but pharmacological trials of sarcopenia have yet to show significant efficacy. In order to conduct a clinical trial within a reasonable time frame, groups that model or display accelerated aging and loss of FFM are necessary. Few studies have used acceptable designs for testing treatment effects, sample sizes or primary outcomes that could provide interpretable findings or effects across studies. Dual energy x-ray absorptiometry (DXA) is the measure of choice for assessing FFM, but sufficient time is needed for changes to be detected accurately and reliably. A tool set that would allow clinical, basic and epidemiological research on sarcopenia to advance rapidly toward diagnosis and treatment phases should be those reflecting function and strength.

Midarm muscle circumference, physical performance and mortality: results from the aging and longevity study in the Sirente geographic area (ilSIRENTE study)

BACKGROUND & AIMS

Sarcopenia has been indicated as a reliable marker of frailty and poor prognosis among the oldest individuals. We evaluated the relationship between midarm muscle circumference (MAMC) and physical performance, muscle strength, functional status and survival in persons aged 80 years or older.

METHODS

Data are from the baseline evaluation of the Aging and Longevity Study in the Sirente Geographic Area (ilSIRENTE Study) (n = 357). MAMC was calculated taking into account the mid upper arm circumference and the triceps skinfold thickness of the right arm. Physical performance was assessed using the physical performance battery score, which is based on three timed tests: 4-m walking speed test, the balance test and the chair stand test. Analyses of covariance were performed to evaluate the relationship between different MAMC levels and physical function. Cox proportional regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals of death by MAMC levels.

RESULTS

After adjustment for potential confounders - which included age, gender, living alone, sensory impairments (hearing and vision), body mass index, albumin and cholesterol - physical performance and function (which were measured using the 4-m walking speed test, the Short Physical Performance Battery score, the hand grip strength), improved significantly as MAMC increased. Compared with those in the low MAMC tertile, subjects in the high MAMC tertile had a lower risk of death (adjusted hazard ratio (HR) 0.45; 95% Confidence Interval (CI) 0.23-0.87).

CONCLUSIONS

The present study suggests that among community-dwelling old-old subjects muscle mass may be positively related to functional performance and survival.

Effects of age and sedentary lifestyle on skeletal muscle NF-kappaB signaling in men

BACKGROUND

Nuclear factor kappa B (NF-kappaB) is a critical signaling molecule of disuse-induced skeletal muscle atrophy. However, few studies have carefully investigated whether similar pathways are modulated with physical activity and age.

METHODS

The present study examined lean mass, maximal force production, and skeletal muscle NF-kappaB signaling in 41 men categorized as sedentary (OS, N = 13, 63.85 +/- 6.59 year), physically active (OA, N = 14, 60.71 +/- 5.54 year), or young and sedentary (YS, N = 14, 21.35 +/- 3.84 year). Muscle tissue from the vastus lateralis was assayed for messenger RNA (mRNA) expression of the beta subunit of IkB kinase (IKKbeta), cytosolic protein content of phosphorylated inhibitor of kappa B alpha (pIKBalpha), and nuclear content of NF-kappaB subunits p50 and p65.

RESULTS

When compared with YS, OS demonstrated age-related muscle atrophy and reduced isokinetic knee extension torque. Physical activity in older individuals preserved maximal isokinetic knee extension torque. OS muscle contained 50% more pIKBalpha than OA and 61% more pIKBalpha than YS. Furthermore, nuclear p65 was significantly elevated in OS compared with YS. OS muscle did not differ from either of the other two groups for nuclear p50 or for mRNA expression of IKKbeta.

CONCLUSIONS

These results indicate that skeletal muscle content of nuclear-bound p65 is elevated by age in humans. The elevation in nuclear-bound p65 appears to be at least partially due to significant increases in pIKBalpha. A sedentary lifestyle appears to play some role in increased IKBalpha; however, further research is needed to identify downstream effects of this increase.

Understanding sarcopenia as a geriatric syndrome

PURPOSE OF REVIEW

Highly prevalent in the population older than 65 years and leading to poor outcomes (functional decline and its related consequences), sarcopenia does not benefit yet either of a clear understanding of its pathophysiology or of precise clinical or biological markers allowing its identification.

RECENT FINDINGS

The new scientific definition of 'geriatric syndromes' challenges the authors to review the current sarcopenia literature, allowing them to affirm that sarcopenia cannot be considered as an age-related disease but as a true 'geriatric syndrome'. More than 50% of the population older than 80 years suffer from this medical condition, which is linked to multiple causations: the ageing process itself, genetic susceptibility, certain life habits, changes in living conditions and a number of chronic diseases. Moreover, sarcopenia favours poor outcomes such as mobility disorders, disability, poor quality of life and death.

SUMMARY

Considering sarcopenia as a geriatric syndrome allows us to request its recognition and assess its multiple risk factors, to implement a clinical and public health approach to the management of sarcopenic patients and population at risk and to disentangle the links among sarcopenia, frailty, disability and mortality.

Association of C-reactive protein and muscle strength in the English Longitudinal Study of Ageing

Sarcopenia has been associated with systemic inflammation and a range of other biological risk factors. The purpose of this study was to assess the systemic inflammation-muscle strength relationship in a large representative community-based cohort of older adults, and to determine the independence of this association from other biological and psychosocial risk factors. Participants were 1,926 men and 2,260 women (aged 65.3 +/- 9.0 years) from the English Longitudinal Study of Ageing, a study of community dwelling older adults. We assessed hand grip strength and lower body strength (time required to complete five chair stands). Biological measures included C-reactive protein (CRP), fibrinogen, cholesterol, haemoglobin, glycated haemoglobin, adiposity, and blood pressure. Approximately 33% of the sample demonstrated elevated concentrations (>or=3 mg/L) of CRP. After adjustments for age, smoking, physical activity, education, inflammatory diseases, and all other biological factors, elevated CRP was associated with poorer hand grip strength and chair stand performance in women but only chair stand performance in men. Low haemoglobin levels were consistently associated with poorer performance on both tests in women and men. These results confirm an independent association between low grade systemic inflammation (as indexed by CRP) and muscle strength that appears to be more robust in women.