New horizons in the pathogenesis, diagnosis and management of sarcopenia

The combined effect of handgrip strength and obesity phenotype on the risk of stroke in Chinese middle-aged and elderly: A cohort study

OBJECTIVE

The aim of this study was to investigate the combined effect of handgrip strength (HGS) and obesity phenotype on the risk of stroke in Chinese middle-aged and elderly people.

METHODS

The data was used from the China Health and Retirement Longitudinal Study (CHARLS). Middle-aged and older adults who participated in surveys between 2011 and 2018 were included in the study. They were divided into 4 different types of obesity phenotypes based on obesity and metabolic status: metabolically healthy non-overweight/obesity (MHNO), metabolically healthy overweight/obesity (MHO), metabolically abnormal non-overweight/obesity (MANO), and metabolically abnormal overweight/obesity (MAO). The HGS level was divided into low and high groups according to the median values. Cox proportional risk regression model was used to analyze the joint effect of HGS and obesity phenotype on the risk of stroke among participants.

RESULTS

A total of 7904 participants aged 58.89±9.08 years were included in this study. After adjusting for potential confounders, high HGS&MHO (HR=1.86, 95 % CI=1.12-3.09), high HGS&MANO (HR=2.01, 95 %CI=1.42-2.86), high HGS&MAO (HR=2.01, 95 % CI=1.37-2.93), low HGS&MHNO (HR=1.57, 95 % CI=1.00-2.46), low HGS&MHO (HR=2.09, 95 % CI=1.29-3.38), low HGS&MANO (HR=2.02, 95 % CI=1.35-3.03), and low HGS&MAO (HR=2.48, 95 % CI=1.72-3.58) group had significantly higher risks of stroke than the high HGS&MHNO group.

CONCLUSION

The coexistence of metabolically unhealthy and low HGS can synergistically increase the risk of stroke in Chinese middle-aged and elderly people.

Health effect of multiple air pollutant mixture on sarcopenia among middle-aged and older adults in China

BACKGROUND

As the global aging process accelerates, the health challenges posed by sarcopenia among middle-aged and older adults are becoming increasingly prominent. However, the available evidence on the adverse effects of air pollution on sarcopenia is limited, particularly in the Western Pacific region. This study aimed to explore relationships of multiple air pollutants with sarcopenia and related biomarkers using the nationally representative database.

METHODS

Totally, 6585 participants aged over 45 years were enrolled from the China Health and Retirement Longitudinal Study (CHARLS) in 2011 and 3443 of them were followed up until 2015. Air pollutants were estimated from high-resolution satellite-based spatial-temporal models. In the cross-sectional analysis, we used generalized linear regression, unconditional logistic regression analytical and restricted cubic spline (RCS) methods to assess the single-exposure and non-linear effects of multiple air pollutants on sarcopenia and related surrogate biomarkers (serum creatinine and cystatin C). Several popular mixture analysis techniques such as Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regression, and quantile-based g-computation (Qgcomp) were further used to examinate the combined effects of multiple air pollutants. Logistic regression was used to further analyze the longitudinal association between air pollution and sarcopenia.

RESULTS

Each interquartile range increase in PM2.5, PM10 and NO2 was significantly associated with an increased risk of sarcopenia, with adjusted odds ratios (aORs) of 1.09 [95 % confidence interval (CI): 1.01, 1.20], 1.24 (95 % CI: 1.14, 1.35) and 1.18 (95 % CI: 1.08, 1.28), respectively. Our findings also showed that five air pollutants were significantly associated with the sarcopenia index. In addition, employing a mixture analysis approach, we confirmed significant combined effects of air pollution mixtures on sarcopenia risk and associated biomarkers, with PM10 and PM2.5 identified as major contributors to the combined effect. The results of the exposure-response (E-R) relationships, subgroup analysis, longitudinal analysis and sensitivity analysis all showed the unfavorable impact of air pollution on sarcopenia risk and related vulnerable populations.

CONCLUSIONS

Single-exposure and co-exposure to multiple air pollutants were positively associated with sarcopenia among middle-aged and older adults in China. Our study provided new evidence that air pollution mixture was significantly associated with sarcopenia related biomarkers.

Saururus chinensis (Lour.) Baill. extract promotes skeletal muscle cell differentiation by positively regulating mitochondrial biogenesis and AKT/mTOR signaling in vitro

Promotion of myoblast differentiation by activating mitochondrial biogenesis and protein synthesis signaling pathways provides a potential alternative strategy to balance energy and overcome muscle loss and muscle disorders. Saururus chinensis (Lour.) Baill. extract (SCE) has been used extensively as a traditional herbal medicine and has several physiological activities, including anti‑asthmatic, anti‑oxidant, anti‑inflammatory, anti‑atopic, anticancer and hepatoprotective properties. However, the effects and mechanisms of action of SCE on muscle differentiation have not yet been clarified. In the present study, it was investigated whether SCE affects skeletal muscle cell differentiation through the regulation of mitochondrial biogenesis and protein synthesis in murine C2C12 myoblasts. The XTT colorimetric assay was used to determine cell viability, and myosin heavy chain (MyHC) levels were determined using immunocytochemistry. SCE was applied to C2C12 myotube at different concentrations (1, 5, or 10 ng/ml) and times (1,3, or 5 days). Reverse transcription‑quantitative PCR and western blotting were used to analyze the mRNA and protein expression change of factors related to differentiation, mitochondrial biogenesis and protein synthesis. Treatment of C2C12 cells with SCE at 1,5, and 10 ng/ml did not affect cell viability. SCE promoted C2C12 myotube formation and significantly increased MyHC expression in a concentration‑ and time‑dependent manner. SCE significantly increased the mRNA and protein expression of muscle differentiation‑specific markers, such as MyHC, myogenic differentiation 1, myogenin, Myogenic Factor 5, and β‑catenin, mitochondrial biosynthesis‑related factors, such as peroxisome proliferator‑activated receptor‑gamma coactivator‑1α, nuclear respirator factor‑1, AMP‑activated protein kinase phosphorylation, and histone deacetylase 5 and AKT/mTOR signaling factors related to protein synthesis. SCE may prevent skeletal muscle dysfunction by enhancing myoblast differentiation through the promotion of mitochondrial biogenesis and protein synthesis.

Relationship between muscle thickness measured by ultrasound and physical functions: A 2-year follow-up study of allogeneic hematopoietic stem cell transplantation recipients

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for hematological malignancies. Several complications following allo-HSCT, such as graft-versus-host disease, infection, and malnutrition, often cause physical dysfunction, and the assessment of physical function and evaluation of muscle mass are incompletely performed. Use of ultrasound (US) allows muscle mass measurement in patients with poor general conditions. In allo-HSCT recipients, the correlation between physical function and muscle thickness, as measured by US, remains unclear.

OBJECTIVE

To clarify whether muscle thickness measured by US correlated with physical function in allo-HSCT recipients.

DESIGN

A single-center prospective cohort study.

SETTING

Hospital.

PATIENTS

Ninety-two patients underwent allo-HSCT at our hospital from April 2017 to March 2019.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Biceps and quadriceps muscle thickness measured by US, grip strength, isometric muscle strength (elbow flexion and knee extension), and 6-minute walking test (6MWT) before allo-HSCT and on days 30, 90, 180, 1 year, and 2 years after allo-HSCT. The implementation rates of these assessments were also investigated.

RESULTS

Correlations were observed between biceps thickness and elbow flexion muscle strength/grip strength before allo-HSCT, on days 30, 90, 180, 1 year, and 2 years after allo-HSCT (r = 0.71/0.74, 0.73/0.72, 0.70/0.79, 0.67/0.75, 0.72/0.75, and 0.85/0.79, respectively, all p < .001). At the same time points, quadriceps thickness moderately correlated with knee extensor strength (r = 0.49, 0.50, 0.45, 0.64, 0.61, and 0.58, all p < .001). However, biceps and quadriceps thicknesses did not correlate with the 6MWT. The percentages of patients measured with US and 6MWT were 93.4% and 82.4% (p = .01) on day 30 and 97.5% and 87.8% (p = .02) on day 90, respectively.

CONCLUSIONS

US assessment may be a useful alternative method for estimating muscle strength in fragile allo-HSCT recipients, particularly when physical function assessment is difficult to quantify.

In the land of not-unhappiness: On the state-of-the-art of targeting aging and age-related diseases by biomedical research

The concept of the Land of Not-Unhappiness refers to the potential achievement of eliminating the pathologies of the aging process. To inform of how close we are to settling in the land, we summarize and review the achievements of research on anti-aging interventions over the last hundred years with a specific focus on strategies that slow down metabolism, compensate for aging-related losses, and target a broad range of age-related diseases. We critically evaluate the existing interventions labeled as "anti-aging," such as calorie restriction, exercise, stem cell administration, and senolytics, to provide a down-to-earth evaluation of their current applicability in counteracting aging. Throughout the text, we have maintained a light tone to make it accessible to non-experts in biogerontology, and provide a broad overview for those considering conducting studies, research, or seeking to understand the scientific basis of anti-aging medicine.

Translatability of mouse muscle-aging for humans: the role of sex

Muscle-aging drives sarcopenia and is a major public health issue. Mice are frequently used as a model for human muscle-aging, however, research investigating their translational value is limited. In addition, mechanisms underlying muscle-aging may have sex-specific features in humans, but it is not yet assessed whether these are recapitulated in mice. Here, we studied the effects of aging on a functional, histological and transcriptional level at multiple timepoints in male and female mice (4, 17, 21 and 25 months), with particular emphasis on sex-differences. The effects of natural aging on the transcriptome of quadriceps muscle were compared to humans on pathway level. Significant loss of muscle mass occurred late, at 25 months, in both male (-17%, quadriceps) and female mice (-10%, quadriceps) compared to young control mice. Concomitantly, we found in female, but not male mice, a slower movement speed in the aged groups compared to the young mice (P < 0.001). Consistently, weighted gene co-expression network analysis revealed a stronger association between the aging-related reduction of movement and aging-related changes in muscle transcriptome of female compared to male mice (P < 0.001). In male, but not female mice, major distinctive aging-related changes occurred in the last age group (25 months), which highlights the necessity for careful selection of age using mice as a muscle-aging model. Furthermore, contrasting to humans, more aging-related changes were found in the muscle transcriptome of male mice compared to female mice (4090 vs. 2285 differentially expressed genes at 25 months, respectively). Subsequently, male mice recapitulated more muscle-aging related pathways characteristic for both male and female humans. In conclusion, our data show that sex has a critical effect on the mouse muscle-aging trajectory, although these do not necessarily reflect sex differences observed in the human muscle-aging trajectory.

Long-term exposure to ambient air pollution with sarcopenia among middle-aged and older adults in China

BACKGROUND

Few studies have examined the role of outdoor air pollution exposure in sarcopenia in Asia. We aimed to investigate the association of outdoor air pollutants exposure with sarcopenia among Chinese adults.

METHODS

This nationally population-representative study used data from the China Health and Retirement Longitudinal Study (CHARLS) in 2015, 11,700 participants at least 45 years old from 125 Chinese cities were included. Sarcopenia status was identified according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria. Ambient annual average air pollutants including fine particulate matter (PM2.5), inhalable particles (PM10), coarse particulate matter (PMcoarse), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO) were estimated by satellite models and ground-based measurements. Multinomial logistic regression models were performed to examine the associations of air pollutants exposure with different status of sarcopenia (including possible sarcopenia and sarcopenia). Stratified analyses were utilized to assess the effect modifiers.

RESULTS

Among the 11,700 participants (52.6% women), the average age was 61.0 years. Each 10 μg/m3 increment of annual PMcoarse was associated with a higher risk of possible sarcopenia (odds ratio (OR) = 1.08, 95% confidence interval (CI) 1.04-1.11). Stratified analyses showed a positive risk of possible sarcopenia in women after exposure to PM10, PMcoarse, and NO2. Ambient NO2 exposure was positively associated with sarcopenia (OR = 1.13, 95% CI 1.04-1.22) in those aged 65 years and older. However, we have not observed differences by sex, age, residence, smoking, and drinking. Robustness results were found for PMcoarse in the sensitivity analyses.

CONCLUSION

This nationwide study suggested that long-term exposure to outdoor air pollution, especially for PMcoarse, was associated with the risk of sarcopenia among Chinese adults. Our findings provide epidemiological implications for protecting healthy ageing by improving air quality.

Association of indoor solid fuel use and long-term exposure to ambient PM2.5 with sarcopenia in China: A nationwide cohort study

BACKGROUND

Little is known about the association between air pollution exposure and sarcopenia in Asia. We aimed to investigate the associations of indoor solid fuel use and long-term exposure to ambient fine particulate matter (PM2.5) with sarcopenia in China.

METHODS

Using a nationally population-representative study, 12,723 participants aged at least 45 years across 125 cities from the China Health and Retirement Longitudinal Study were enrolled in 2011, and further 3110 participants were followed up until 2013. Sarcopenia status was classified according to the Asian Working Group for Sarcopenia 2019 criteria. Household fuel types used for heating and cooking were assessed using a standard questionnaire. Ambient annual PM2.5 was estimated using satellite-based spatiotemporal models. Multinomial logistic regression as well as the multiplicative interaction and additive interaction analysis were used to explore the associations of indoor solid fuel and ambient PM2.5 with different status of sarcopenia.

RESULTS

Of the 12,723 participants, 6071 (47.7%) were men. In the cross-sectional analyses, compared with clean fuel, using solid fuel for heating and cooking, separately or simultaneously, was significantly associated with a higher risk of both possible sarcopenia and sarcopenia. Each 10 μg/m3 increment of PM2.5 was positively related to possible sarcopenia (adjusted odds ratio, [aOR] 1.04, 1.02-1.07) and sarcopenia (1.06, 1.01-1.12). We found a significant interaction between solid fuel use for heating and ambient PM2.5 exposure with possible sarcopenia. During a two-year follow-up, solid fuel use was associated with incident possible sarcopenia (aOR 1.59, 1.17-2.15). These associations did not differ by sex and age, while participants living in a house with poor cleanliness might have a higher risk of sarcopenia.

CONCLUSIONS

Indoor solid fuel use and long-term exposure to ambient PM2.5 were associated with a higher risk of sarcopenia among Chinese adults. These findings provide implications for promoting healthy aging by reducing air pollution.

Hallmarks of ageing in human skeletal muscle and implications for understanding the pathophysiology of sarcopenia in women and men

Ageing is a complex biological process associated with increased morbidity and mortality. Nine classic, interdependent hallmarks of ageing have been proposed involving genetic and biochemical pathways that collectively influence ageing trajectories and susceptibility to pathology in humans. Ageing skeletal muscle undergoes profound morphological and physiological changes associated with loss of strength, mass, and function, a condition known as sarcopenia. The aetiology of sarcopenia is complex and whilst research in this area is growing rapidly, there is a relative paucity of human studies, particularly in older women. Here, we evaluate how the nine classic hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication contribute to skeletal muscle ageing and the pathophysiology of sarcopenia. We also highlight five novel hallmarks of particular significance to skeletal muscle ageing: inflammation, neural dysfunction, extracellular matrix dysfunction, reduced vascular perfusion, and ionic dyshomeostasis, and discuss how the classic and novel hallmarks are interconnected. Their clinical relevance and translational potential are also considered.

Reference values for Jamar+ digital dynamometer hand grip strength in healthy adults and in adults with non-communicable diseases or osteoarthritis: the Norwegian Tromsø study 2015-2016

Hand grip strength (HGS) is a key indicator of intrinsic capacity and has shown good predictive ability for morbidity and mortality. Reference values from normative populations are valuable, and such data from the Norwegian population are scarce. Normative values for the digital Jamar+ dynamometer are largely lacking.HGS was assessed in the Norwegian Tromsø study, survey 7 in 2015-2016 for 7824 participants (9324 invited) aged 40+ using a Jamar+ digital dynamometer, and three measurements for each hand were performed following the Southampton protocol. To account for non-response, full Tromsø population data, by age, education and sex, were collected from registry data from microdata.no, a service from Statistics Norway, and were then used as post-stratification weights, to provide standardized HGS values. HGS was higher in men than in women and inversely associated with age. Men and women with a history of non-communicable diseases had lower HGS than those without these conditions, while osteoarthritis was associated with lower HGS only among men. Lower height was associated with lower HGS, especially at younger ages in men. This article provides up-to-date references values for HGS in the community-dwelling population aged 40+ with or without osteoarthritis or non-communicable diseases, in Tromsø, Norway. These reference values will guide clinicians and researchers.

The association of dietary patterns with muscle mass and strength in old age: The Hordaland Health Study

PURPOSE

The single nutrient approach in nutrition research lacks the ability to account for synergistic relationships between dietary components. Current evidence suggests that diet quality, reflecting overall dietary intake, may influence muscle health. In a community-based observational study in Western Norway, we examined dietary patterns in relation to muscle mass and strength at age 67-70.

METHODS

The current analysis was conducted in men and women of The Hordaland Health Study (HUSK), who participated in both the second (HUSK2) and third study wave (HUSK3). Dietary patterns were extracted by principal component analysis (PCA) on food frequency questionnaire (FFQ) data. Individual dietary pattern scores (DPS) for HUSK2 (age 46-49) and HUSK3 (age 67-70), and overall DPS (oDPS) were calculated. Outcome variables were appendicular skeletal muscle mass (ASMM) and handgrip strength (HGS) measured in HUSK3. The relationships of HUSK3 DPS and oDPS with ASMM and HGS were assessed by multivariate linear regression analysis adjusted for potential confounding factors.

RESULTS

We identified three distinct dietary patterns, labelled 'Western', 'Healthy', and 'Sweets-focused'. A significant positive association was observed between the oDPS for the 'Healthy' dietary pattern and ASMM in both men and women at age 67-70. No significant associations were found between HUSK3 DPS or oDPS for any of the identified dietary patterns and HGS in our population.

CONCLUSION

Higher oDPS on a dietary pattern predominantly rich in fish, vegetables, nuts and seeds, fruit and berries, and eggs was associated with better ASMM at age 67-70. To establish the influence of diet quality on muscle health, further long-term studies with repeated dietary assessments are warranted.

7β-Hydroxycholesterol and 7-ketocholesterol: New oxidative stress biomarkers of sarcopenia inducing cytotoxic effects on myoblasts and myotubes

Aging is a complex biological process which can be associated with skeletal muscle degradation leading to sarcopenia. The aim of this study consisted i) to determine the oxidative and inflammatory status of sarcopenic patients and ii) to clarify the impact of oxidative stress on myoblasts and myotubes. To this end, various biomarkers of inflammation (C-reactive protein (CRP), TNF-α, IL-6, IL-8, leukotriene B4 (LTB4)) and oxidative stress (malondialdehyde, conjugated dienes, carbonylated proteins and antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase) as well as oxidized derivatives of cholesterol formed by cholesterol autoxidation (7-ketocholesterol, 7β-hydroxycholesterol), were analyzed. Apelin, a myokine which contributes to muscle strength, was also quantified. To this end, a case-control study was conducted to evaluate the RedOx and inflammatory status in 45 elderly subjects (23 non-sarcopenic; 22 sarcopenic) from 65 years old and higher. SARCopenia-Formular (SARC-F) and Timed Up and Go (TUG) tests were used to distinguish between sarcopenic and non-sarcopenic subjects. By using red blood cells, plasma and/or serum, we observed in sarcopenic patients an increased activity of major antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase) associated with lipid peroxidation and protein carbonylation (increased level of malondialdehyde, conjugated dienes and carbonylated proteins). Higher levels of 7-ketocholesterol and 7β-hydroxycholesterol were also observed in the plasma of sarcopenic patients. Significant differences were only observed with 7β-hydroxycholesterol. In sarcopenic patients comparatively to non-sarcopenic subjects, significant increase of CRP, LTB4 and apelin were observed whereas similar levels of TNF-α, IL-6 and IL-8 were found. The increased plasma level of 7-ketocholesterol and 7β-hydroxycholesterol in sarcopenic patients led us to study the cytotoxic effect of these oxysterols on undifferentiated (myoblasts) and differentiated (myotubes) murine C2C12 cells. With the fluorescein diacetate and sulforhodamine 101 assays, an induction of cell death was observed both on undifferentiated and differentiated cells: the cytotoxic effects were less pronounced with 7-ketocholesterol. In addition, IL-6 secretion was never detected whatever the culture conditions, TNF-α secretion was significantly increased on undifferentiated and differentiated C2C12 cells treated with 7-ketocholesterol- and 7β-hydroxycholesterol, and IL-8 secretion was increased on differentiated cells. 7-ketocholesterol- and 7β-hydroxycholesterol-induced cell death was strongly attenuated by α-tocopherol and Pistacia lentiscus L. seed oil both on myoblasts and/or myotubes. TNF-α and/or IL-8 secretions were reduced by α-tocopherol and Pistacia lentiscus L. seed oil. Our data support the hypothesis that the enhancement of oxidative stress observed in sarcopenic patients could contribute, especially via 7β-hydroxycholesterol, to skeletal muscle atrophy and inflammation via cytotoxic effects on myoblasts and myotubes. These data bring new elements to understand the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease.

Slow or fast: Implications of myofibre type and associated differences for manifestation of neuromuscular disorders

Many neuromuscular disorders can have a differential impact on a specific myofibre type, forming the central premise of this review. The many different skeletal muscles in mammals contain a spectrum of slow- to fast-twitch myofibres with varying levels of protein isoforms that determine their distinctive contractile, metabolic, and other properties. The variations in functional properties across the range of classic 'slow' to 'fast' myofibres are outlined, combined with exemplars of the predominantly slow-twitch soleus and fast-twitch extensor digitorum longus muscles, species comparisons, and techniques used to study these properties. Other intrinsic and extrinsic differences are discussed in the context of slow and fast myofibres. These include inherent susceptibility to damage, myonecrosis, and regeneration, plus extrinsic nerves, extracellular matrix, and vasculature, examined in the context of growth, ageing, metabolic syndrome, and sexual dimorphism. These many differences emphasise the importance of carefully considering the influence of myofibre-type composition on manifestation of various neuromuscular disorders across the lifespan for both sexes. Equally, understanding the different responses of slow and fast myofibres due to intrinsic and extrinsic factors can provide deep insight into the precise molecular mechanisms that initiate and exacerbate various neuromuscular disorders. This focus on the influence of different myofibre types is of fundamental importance to enhance translation for clinical management and therapies for many skeletal muscle disorders.

Air pollution weaken your muscle? Evidence from a cross-sectional study on sarcopenia in central China

BACKGROUND

As the world experiences a demographic shift towards aging populations, there will be a significant surge in the number of sarcopenia patients, along with an unprecedented expansion in the associated economic burden. The multitudinous risk factors for sarcopenia have been reported, but evidence for air pollution remains rare.

METHODS

This cross-sectional study employed multi-stage random sampling to select 1592 participants over 40 years of age from Hubei Province. Daily mean concentrations of air pollutants were collected ChinaHighAirPollutants dataset. Unconditional logistic regression models were utilized to investigate the associations between air pollution and sarcopenia.

RESULTS

For each 1 μg/m³ increase in PM_2.5, PM₁₀, SO₂ and O₃, there were corresponding elevations of 11.1% [95% confidence interval (CI): 4.9, 17.7], 4.3% (95% CI: 1.4, 7.2), 22.6% (95% CI: 7.2, 40.1) and 9.3% (95% CI: 0.7, 18.7) in the risk of sarcopenia, respectively. The associations of PM_2.5/PM₁₀/O₃-sarcopenia were more pronounced in females, with corresponding odds ratios (ORs) and 95% CIs of 1.179 (1.062, 1.310), 1.079 (1.027, 1.135) and 1.180 (1.026, 1.358), separately. Additionally, individuals residing in rural areas were more susceptible to the effects of PM_2.5 and PM₁₀. Current/ever smokers or drinkers were also at higher risk of developing sarcopenia caused by PM_2.5, PM₁₀ and O₃ exposure. Mixture analyses show a surge of 48.4% (95% CI: 3.6%, 112.5%) in the likelihood of suffering from sarcopenia, and the joint impacts of the air pollution were mainly driven by PM_2.5.

CONCLUSIONS

Our results produced evidence for a relationship between air pollution exposure and the increased prevalence of sarcopenia in China. Public health and relevant departments should make efforts to prevent sarcopenia, particularly in China experiencing rapid demographic aging.

Exercise for sarcopenia in older people: A systematic review and network meta-analysis

BACKGROUND

Sarcopenia is a serious public health concern among older adults worldwide. Exercise is the most common intervention for sarcopenia. This study aimed to compare the effectiveness of different exercise types for older adults with sarcopenia.

METHODS

Randomized controlled trials (RCTs) that examined the effectiveness of exercise interventions on patient-important outcomes for older adults with sarcopenia were eligible. We systematically searched MEDLINE, Embase and Cochrane Central Register of Controlled Trials via Ovid until 3 June 2022. We used frequentist random-effects network meta-analyses to summarize the evidence and applied the Grading of Recommendations, Assessment, Development, and Evaluations framework to rate the certainty of evidence.

RESULTS

Our search identified 5988 citations, of which 42 RCTs proved eligible with 3728 participants with sarcopenia (median age: 72.9 years, female: 73.3%) with a median follow-up of 12 weeks. We are interested in patient-important outcomes that include mortality, quality of life, muscle strength and physical function measures. High or moderate certainty evidence suggested that resistance exercise with or without nutrition and the combination of resistance exercise with aerobic and balance training were the most effective interventions for improving quality of life compared to usual care (standardized mean difference from 0.68 to 1.11). Moderate certainty evidence showed that resistance and balance exercise plus nutrition (mean difference [MD]: 4.19 kg) was the most effective for improving handgrip strength (minimally important difference [MID]: 5 kg). Resistance and balance exercise with or without nutrition (MD: 0.16 m/s, moderate) were the most effective for improving physical function measured by usual gait speed (MID: 0.1 m/s). Moderate certainty evidence showed that resistance and balance exercise (MD: 1.85 s) was intermediately effective for improving physical function measured by timed up and go test (MID: 2.1 s). High certainty evidence showed that resistance and aerobic, or resistance and balance, or resistance and aerobic exercise plus nutrition (MD from 1.72 to 2.28 s) were intermediately effective for improving physical function measured by the five-repetition chair stand test (MID: 2.3 s).

CONCLUSIONS

In older adults with sarcopenia, high or moderate certainty evidence showed that resistance exercise with or without nutrition and the combination of resistance exercise with aerobic and balance training were the most effective interventions for improving quality of life. Adding nutritional interventions to exercise had a larger effect on handgrip strength than exercise alone while showing a similar effect on other physical function measures.

Association of Alpha-Actinin-3 Polymorphism With Sarcopenia in Kidney Transplant Recipients

BACKGROUND

Sarcopenia is defined as the loss of skeletal muscle mass and function and is associated with increased mortality. Certain genetic polymorphisms represent risk factors used to assess the incidence of sarcopenia; however, few studies have evaluated the association between genetic polymorphisms and sarcopenia after kidney transplantation (KTx). We examined single-nucleotide polymorphisms (SNPs) in the genes involved in sarcopenia after KTx.

METHODS

Sixty-five patients who underwent KTx were enrolled in this study. We used the psoas mass index (PMI; the cross-sectional area of the bilateral psoas muscle/height) as a surrogate marker for assessing the extent of sarcopenia. We determined the PMI before KTx and 1 year after KTx, and we identified 5 SNPs in 5 genes associated with sarcopenia in the general population. Finally, the link between the changes in PMI 1 year after KTx and each SNP was examined.

RESULTS

The median PMI before KTx and 1 year after KTx was 7.4 (4.6-13.2) and 7.0 (3.6-13.6), respectively. The PMI decreased in 43 patients (66.2%). The alpha-actinin-3 rs1815739 genotype was associated with changes in PMI; the distribution of CT+TT genotypes in the PMI decrease group was significantly higher than that of the CC genotype (odds ratio, 4.23; 95% CI 0.05-0.97; P = 0.025). Moreover, the T allele frequency was significantly higher in the PMI decrease group than in the PMI increase group (odds ratio, 2.34; 95% CI 0.18-0.950; P = 0.025).

CONCLUSION

The alpha-actinin-3 rs1815739 genotype may represent a genetic risk factor for sarcopenia after KTx.

Milk intake across adulthood and muscle strength decline from mid- to late life: the MRC National Survey of Health and Development

Milk is a source of several nutrients which may be beneficial for skeletal muscle. Evidence that links lower milk intake with declines in muscle strength from midlife to old age is lacking. We used data from the Medical Research Council National Survey of Health and Development to test sex-specific associations between milk consumption from age 36 to 60-64 years, low grip strength (GS) or probable sarcopenia, and GS decline from age 53 to 69 years. We included 1340 men and 1383 women with at least one measure of both milk intake and GS. Milk intake was recorded in 5-d food diaries (aged 36, 43, 53 and 60-64 years), and grand mean of total, reduced-fat and full-fat milk each categorised in thirds (T1 (lowest) to T3 (highest), g/d). GS was assessed at ages 53, 60-64, and 69 years, and probable sarcopenia classified at the age of 69 years. We employed logistic regression to examine the odds of probable sarcopenia and multilevel models to investigate decline in GS in relation to milk intake thirds. Compared with T1, only T2 (58·76-145·25 g/d) of reduced-fat milk was associated with lower odds of sex-specific low GS at the age of 69 years (OR (95 % CI): 0·59 (0·37, 0·94), P = 0·03). In multilevel models, only T3 of total milk (≥ 237·52 g/d) was associated with stronger GS in midlife in men (β (95 % CI) = 1·82 (0·18, 3·45) kg, P = 0·03) compared with T1 (≤ 152·0 g/d), but not with GS decline over time. A higher milk intake across adulthood may promote muscle strength in midlife in men. Its role in muscle health in late life needs further examination.

Low-Plasma Insulin-Like Growth Factor-1 Associates With Increased Mortality in Chronic Kidney Disease Patients With Reduced Muscle Strength

OBJECTIVES

Chronic kidney disease (CKD) leads to metabolic and nutritional abnormalities including resistance to insulin-like growth factor-1 (IGF-1) action, and reduced muscle mass and strength. Low IGF-1 as well as low hand-grip muscle strength (HGS) are independent predictors of increased mortality in CKD patients.

METHODS

In 685 patients (CKD Stage 3-5, median age 58 years; 62% men), baseline measurements of IGF-1, HGS, subjective global assessment (SGA), lean body mass index (LBMI), and metabolic and inflammatory biomarkers potentially linked to IGF-1 were analyzed in relation to mortality during 5 years of follow-up. We compared survival in 4 groups with high or low (cut-offs defined by receiver operating characteristic curve analysis) levels of IGF-1 and HGS.

RESULTS

Patients with low IGF-1 were older; had lower BMI, HGS, and LBMI, were more likely to have diabetes, cardiovascular disease (CVD), and malnutrition (SGA >1); and had high-sensitivity C-reactive protein levels. During 5 years of follow-up, 208 patients died. The mortality rate was highest among patients with Low IGF-1 + Low HGS. In competing-risk regression analysis, Low IGF-1 + Low HGS was independently associated with 2.8 times higher all-cause mortality risk than Low IGF-1 + High HGS, after adjusting for Framingham's CVD risk score, presence of CVD, SGA, dialysis status, high-sensitivity C-reactive protein, albumin, LBMI, and sample time in freezer.

CONCLUSION

Low IGF-1 was associated with increased all-cause mortality in patients who also had low HGS but not in those with high HGS, suggesting that the association of IGF-1 with survival in CKD patients depends on nutritional status.

Association between early life exposure to the great famine and possible sarcopenia in older Chinese adults: a national cross-sectional study

OBJECTIVES

We used data from the China Health and Retirement Longitudinal Study (CHARLS) to investigate how an early life famine exposure affected possible sarcopenia (PS) and to explore the extent to which a sex difference exists in the association among older Chinese adults, as well as whether risk factors modify the association.

DESIGN

Cross-sectional study.

SETTING

28 provinces of China.

PARTICIPANTS

Considering that the Great Chinese Famine lasted from the spring of 1959 to the fall of 1961, 3557 participants were selected and categorised into four subgroups based on their date of birth: unexposed group (1 October 1962 to 30 September 1964), fetal exposed group (1 October 1959 to 30 September 1961), infant exposed group (1 January 1958 to 31 December 1958) and preschool exposed group (1 January 1956 to 31 December 1957).

OUTCOME MEASURE

PS was defined as having low muscle strength or low physical performance.

METHODS

We used multivariable logistic models to analyse the association between early life famine exposure and the risk of PS in elderly life.

RESULTS

The prevalences of PS among individuals in the unexposed, fetal, infant and preschool exposed groups were 15.1%, 14.4%, 23.6% and 21.9%, respectively. Compared with the unexposed group, the infant (OR: 1.55; 95% CI 1.17 to 2.05) and preschool exposed (OR: 1.46; 95% CI 1.17 to 1.82) groups exhibited significantly higher risks of PS. In men, the infant (OR: 2.15; 95% CI 1.40 to 3.31) and preschool exposed (OR: 1.78; 95% CI 1.23 to 2.57) groups were more likely to have PS, but no significant increase was seen in women. In both sexes, prevalence of PS was unrelated to early life famine exposure in the urban, underweight and normal weight subgroups.

CONCLUSIONS

Early life exposure to the Great Chinese Famine was associated with a higher risk of PS in older adults. Keeping normal nutritional status in elderly life might help avoid the risk of PS, whatever the effect of early famine exposure.

Diagnosis, prevalence, and outcomes of sarcopenia in kidney transplantation recipients: A systematic review and meta-analysis

The prevalence of sarcopenia and its clinical predictors and clinical impact vary among kidney transplant recipients (KTRs), in part because of different diagnostic criteria. This study aimed to assess the reported diagnosis criteria of sarcopenia and compare them in terms of prevalence, clinical predictors, and impact of sarcopenia. The Medline, Embase, and Cochrane Library were searched for the full-length reports published until 28 January 2022. The subgroup analysis, meta-regression, and sensitivity analysis were performed and heterogeneity was assessed using the I² . A total of 681 studies were retrieved, among which only 23 studies (including 2535 subjects, 59.7% men, mean age 49.8 years) were eventually included in the final analysis. The pooled prevalence in these included studies was 26% [95% confidence interval (95% CI): 20-34%, I²  = 93.45%], including 22% (95% CI: 14-32%, I²  = 88.76%) in men and 27% (95% CI: 14-41%, I²  = 90.56%) in women (P = 0.554 between subgroups). The prevalence of sarcopenia diagnosed using low muscle mass was 34% (95% CI: 21-48%, I²  = 95.28%), and the prevalence of using low muscle mass in combination with low muscle strength and/or low physical performance was 21% (95% CI: 15-28%, I²  = 90.37%) (P = 0.08 between subgroups). In meta-regression analyses, the mean age (regression coefficient: 1.001, 95% CI: 0.991-1.011) and percentage male (regression coefficient: 0.846, 95% CI: 0.367-1.950) could not predict the effect size. Lower body mass index (odds ratio (OR): 0.57, 95% CI: 0.39-0.84, I²  = 61.5%), female sex (OR: 0.31, 95% CI: 0.16-0.61, I²  = 0.0%), and higher age (OR: 1.08, 95% CI: 1.05-1.10, I²  = 10.1%) were significantly associated with a higher risk for sarcopenia in KTRs, but phase angle (OR: 0.81, 95% CI: 0.16-4.26, I²  = 84.5%) was not associated with sarcopenia in KTRs. Sarcopenia was not associated with rejections (risk ratio (RR): 0.67, 95% CI: 0.23-1.92, I²  = 12.1%), infections (RR: 1.03, 95% CI: 0.34-3.12, I²  = 87.4%), delayed graft functions (RR: 0.81, 95% CI: 0.46-1.43, I²  = 0.0%), and death (RR: 0.95, 95% CI: 0.32-2.82, I²  = 0.0%) in KRTs. Sarcopenia was found to be very common in KRTs. However, we have not found that sarcopenia had a negative impact on clinical health after kidney transplantation. Large study cohorts and multicentre longitudinal studies in the future are urgently needed to explore the prevalence and prognosis of sarcopenia in kidney transplant patients.

Effect of Electrical Muscle Stimulation and Resistance Exercise Intervention on Physical and Brain Function in Middle-Aged and Older Women

This study investigated the effectiveness of electrical muscle stimulation (EMS) with resistance exercise training (ERT) and resistance exercise training (RT) on physical and brain function in middle-aged and older women. Method: Forty-eight participants were randomly allocated into three groups: (i) ERT (n = 16), (ii) RT (n = 16), and (iii) control group (n = 16). The intervention session was 50 min long and performed three times/week for four weeks. The ERT group performed quadriceps setting, straight leg raises, and ankle pump exercises while constantly receiving EMS on their quadriceps muscle on both legs. The RT group performed the same exercise without EMS. Physical function was measured using skeletal muscle mass index (SMI), handgrip strength, gait speed, five times sit-to-stand test (FTSS) and timed up-and-go test (TUG). Brain function was assessed with electroencephalogram measurement of whole brain activity. Results: After four-week intervention, significant improvements were observed in SMI (p < 0.01), phase angle (p < 0.05), and gait speed (p < 0.05) in the ERT group compared to the control group. ERT also increased muscle strength (p < 0.05) and mobility in lower limbs as observed in FTSS and TUG tests (p < 0.05) at post-intervention compared to the baseline. In the ERT group, significant positive changes were observed in Beta1 band power, Theta band power, and Alpha1 band whole brain connectivity (p < 0.005) compared to the control group. Conclusions: Our findings showed that ERT can improve muscle and brain function in middle-aged and older adults during a four-week intervention program whereas significant improvements were not observed with RT. Therefore might be one of the feasible alternative intervention to RT for the prevention of muscle loss whilst improving brain function for middle-aged and older population.

Impact of cancer cachexia on respiratory muscle function and the therapeutic potential of exercise

Cancer cachexia is defined as a multi-factorial syndrome characterised by an ongoing loss of skeletal muscle mass and progressive functional impairment, estimated to affect 50-80% of patients and responsible for 20% of cancer deaths. Elevations in the morbidity and mortality rates of cachectic cancer patients has been linked to respiratory failure due to atrophy and dysfunction of the ventilatory muscles. Despite this, there is a distinct scarcity of research investigating the structural and functional condition of the respiratory musculature in cancer, with the majority of studies exclusively focusing on limb muscle. Treatment strategies are largely ineffective in mitigating the cachectic state. It is now widely accepted that an efficacious intervention will likely combine elements of pharmacology, nutrition and exercise. However, of these approaches, exercise has received comparatively little attention. Therefore, it is unlikely to be implemented optimally, whether in isolation or combination. In consideration of these limitations, the current review describes the mechanistic basis of cancer cachexia and subsequently explores the available respiratory- and exercise-focused literature within this context. The molecular basis of cachexia is thoroughly reviewed. The pivotal role of inflammatory mediators is described. Unravelling the mechanisms of exercise-induced support of muscle via antioxidant and anti-inflammatory effects in addition to promoting efficient energy metabolism via increased mitochondrial biogenesis, mitochondrial function and muscle glucose uptake provide avenues for interventional studies. Currently available pre-clinical mouse models including novel transgenic animals provide a platform for the development of multi-modal therapeutic strategies to protect respiratory muscles in people with cancer.

Is ambient air pollution associated with sarcopenia? Results from a nation-wide cross-sectional study

BACKGROUND

sarcopenia is a disease that involves the degeneration of muscle strength, muscle mass and physical performance. It remains unknown whether air pollution exposure increases the risk of sarcopenia.

METHODS

the baseline survey of the UK Biobank was used in this study. Sarcopenia was identified according to European Working Group on Sarcopenia in Older People 2 (EWGSOP2) and classified into non-sarcopenia and probable sarcopenia. Land use regressions were used to estimate concentrations of particulate matter (PM2.5), coarse particles (PMcoarse), PM10, PM2.5 absorbance, nitrogen dioxide (NO2) and nitrogen oxides (NOx). Logistic regression models were applied to estimate the associations between air pollution and sarcopenia and its components.

RESULTS

out of 352,265 participants, 28,710 (8.2%) were identified with probable sarcopenia. In adjusted models, there were increased odds of probable sarcopenia for each interquartile range increase in PM2.5 (OR: 1.06; 95% CI: 1.04, 1.07), PM10 (OR: 1.15; 95% CI: 1.13, 1.17), PMcoarse (OR: 1.02; 95% CI:1.01, 1.03), PM2.5 absorbance (OR: 1.08; 95% CI: 1.07, 1.10), NO2 (OR: 1.12; 95% CI:1.10, 1.14) and NOx (OR: 1.06; 95% CI: 1.05, 1.08).

CONCLUSIONS

this study suggests that exposure to ambient air pollution might be one risk factor of sarcopenia. Prospective studies are needed to further confirm our findings.

Recent advances in cell-based and cell-free therapeutic approaches for sarcopenia

Sarcopenia is a progressive loss of muscle mass and function that is connected with increased hospital expenditures, falls, fractures, and mortality. Although muscle loss has been related to aging, injury, hormonal imbalances, and diseases such as malignancies, chronic obstructive pulmonary disease, heart failure, and kidney failure, the underlying pathogenic mechanisms of sarcopenia are unclear. Exercise-based interventions and multimodal strategies are currently being considered as potential therapeutic approaches to prevent or treat these diseases. Although drug therapy research is ongoing, no drug has yet been proven to have a substantial safety and clinical value to be the first drug therapy to be licensed for sarcopenia. To better understand the molecular alterations underlying sarcopenia and effective treatments, we review leading research and available findings from the systemic change to the muscle-specific microenvironment. Furthermore, we explore possible mechanisms of sarcopenia and provide new knowledge for the development of novel cell-free and cell-based therapeutics. This review will assist researchers in developing better therapies to improve muscle health in the elderly.

Ultrasound and magnetic resonance imaging as diagnostic tools for sarcopenia in immune-mediated rheumatic diseases (IMRDs)

Sarcopenia is characterized by loss of muscle mass, altered muscle composition, fat and fibrous tissue infiltration, and abnormal innervation, especially in older individuals with immune-mediated rheumatic diseases (IMRDs). Several techniques for measuring muscle mass, strength, and performance have emerged in recent decades. The portable dynamometer and gait speed represent the most frequently used tools for the evaluation of muscle strength and physical efficiency, respectively. Aside from dual-energy, X-ray, absorptiometry, and bioelectrical impedance analysis, ultrasound (US) and magnetic resonance imaging (MRI) techniques appear to have a potential role in evaluating muscle mass and composition. US and MRI have been shown to accurately identify sarcopenic biomarkers such as inflammation (edema), fatty infiltration (myosteatosis), alterations in muscle fibers, and muscular atrophy in patients with IMRDs. US is a low-cost, easy-to-use, and safe imaging method for assessing muscle mass, quality, architecture, and biomechanical function. This review summarizes the evidence for using US and MRI to assess sarcopenia.

Advancing our understanding of skeletal muscle across the lifecourse: Protocol for the MASS_Lifecourse study and characteristics of the first 80 participants

INTRODUCTION

Sarcopenia, the age-related loss of skeletal muscle strength and mass, carries a significant burden for affected individuals. There has been little investigation of sarcopenia using experimental medicine techniques to study human muscle tissue in detail. The aim of the Muscle Ageing Sarcopenia Studies Lifecourse (MASS_Lifecourse) study is to recruit up to 160 participants, equally divided between females and males between ages 45 and 85 years for detailed phenotyping of skeletal muscle health. Here we describe the protocol for the study and the characteristics of the first 80 participants.

METHODS

We are recruiting participants from three sources in the north-east of England. Study fieldwork comprises a home visit (or videocall) for consent and assessment of health, cognition, lifestyle, and wellbeing. This is followed by a visit to a clinical research facility for assessment of sarcopenia status and collection of samples including a vastus lateralis muscle biopsy. We produced descriptive statistics for the first 80 participants, including expressing their grip strength relative to normative data in the form of Z-scores.

RESULTS

The first 80 participants (53.8 % female) covered the target ages, ranging from 48 to 84 years. They were regularly physically active, reported good physical function and had a prevalence of sarcopenia (including probable sarcopenia) of 11.3 % based on the revised European consensus. Their grip strength was similar to that in the general population, with a mean Z-score of 0.09 standard deviations (95 % CI: -1.64, 1.83) above that expected.

CONCLUSIONS

The MASS_Lifecourse study combines comprehensive health and lifestyle data with a range of biological samples including skeletal muscle. The findings from planned analyses should contribute to improvements in the diagnosis, treatment, and prevention of sarcopenia.

The top 100 most-cited articles on exercise therapy for sarcopenia: A bibliometric analysis

Objective

Vast quantities of literature regarding the applications of exercise therapy for sarcopenia have been published. The main objective of this study is to determine the top 100 most-cited articles and analyze their bibliometric characteristics.

Design

This study reports a bibliometric analysis via a systematic search of the academic literature regarding the applications of exercise therapy for sarcopenia.

Methods

All databases in the Web of Science were searched with the following strategy: term search (TS) = (exercise^* OR training OR “physical activit^*”) AND TS = (sarcopenia) on 25 February 2022. The results were presented in descending order by their total citations. The list of the top 100 articles was finally determined by negotiation of two independent researchers.

Results

The top 100 articles were published between 1993 and 2020. More than half of the articles (n = 54) were published during the decade 2006–2015. Total citations of the top 100 articles ranged from 155 to 1,131 with a median of 211.5. The average of annual citations was constantly increasing with year (P < 0.05). The most studied exercise therapy is strength/resistance training, with about 71% articles had discussed about it. The top 100 articles were from 54 different journals, and the Journal of Applied Physiology was the journal that contributed the most articles (n = 8). A total of 75 different first corresponding authors from 15 countries made contributions to the top 100 list. Luc J.C. van Loon from the Maastricht University in the Netherlands published the most articles (n = 5) as the first corresponding author. Most articles (87%) were from North America (58%) and Europe (29%), while the United States as a country contributed over half of the articles (51%).

Conclusion

Our study determined the top 100 most-cited articles on exercise therapy for sarcopenia and analyzed their bibliometric characteristics, which may provide a recommended list for researchers in this field and pave the way for further research.

Prehabilitation prior to intestinal resection in Crohn’s disease patients: An opinion review

Patients with Crohn’s disease (CD) are at a considerable risk for intestinal surgery. Approximately 25% of patients with CD will undergo an intestinal resection within 10 years of diagnosis. Postoperative complications after CD surgery have been reported in 20%-47% of the patients. Both general and CD-related risk factors are associated with postoperative complications, and comprise non-modifiable (e.g., age) and potentially modifiable risk factors (e.g., malnutrition). Prehabilitation focuses on the preoperative period with strategies designed to optimize modifiable risk factors concerning the physical and mental condition of the individual patient. The aim of prehabilitation is to enhance postoperative recovery and return to or even improve preoperative functional capacity. Preoperative improvement of nutritional status, physical fitness, cessation of smoking, psychological support, and critical revision of preoperative use of CD medication are important strategies. Studies of the effect on postoperative outcome in CD patients are scarce, and guidelines lack recommendations on tailored management. In this opinion review, we review the current evidence on the impact of screening and management of nutritional status, physical fitness, CD medication and laboratory values on the postoperative course following an intestinal resection in CD patients. In addition, we aim to provide guidance for individualized multimodal prehabilitation in clinical practice concerning these modifiable factors.

Sarcopenia, a major clinical problem in old age, potential causes, clinical consequences and therapeutic possibilities

Sarcopenia or degeneration of skeletal muscle tissue with aging, is responsible for functional de-cline and loss of independence in older adults. The purpose of this article is to review the current definitions of sarcopenia, its potential causes, clinical consequences and the potential for prop-hylactic and curative intervention. Sarcopenia is recognized as a major clinical problem for the elderly, and the research in this area is growing exponentially. One of the most important recent developments has been convergence in the operational definition of sarcopenia that combines muscle mass, strength and muscle function. In 2010, the European Working Group on Sarcopenia in Oder People (EWGSOP) published a definition of sarcopenia aimed at promoting progress in the identification and care of the elderly. In early 2018 (EWGSOP2) he met again to update the original definition to reflect the scientific and clinical evidence that has been built over the past decade. The cause of sarcopenia is considered to be multifactorial: hormonal changes, neurologi-cal decline, sedentary / immobilization for a long period, chronic diseases, obesity, all these fac-tors contribute to the onset of sarcopenia. Prophylactic or curative interventions are essentially aimed at nutrition and exercise. Although pharmaceutical agents are developed that target seve-ral biological pathways, proper nutrition and specific physical exercises remain the gold stan-dard for therapy. Through this review, we want to draw attention to the need to implement complex analyzes of the elderly patient, regardless of the acute problem with which he presents himself at the consultation. These analyses should contain tests, measurements, questionnaires that identify in time a possible musculoskeletal degeneration. The results did not show any sig-nificant difference between the perception of sarcopenia, the way of approaching it and the prophylactic or therapeutic treatment. We focused on this pathology because sarcopenia is rela-tively newly observed, defined, it is not fully investigated and a clinical skill has not been for-med for the evaluation of the elderly patient. Keywords: Skeletal muscle, elderly, sarcopenia, degeneration, exercises

Preoperative maximum phonation time as a predictor of pneumonia in patients undergoing esophagectomy

PURPOSE

Esophagectomy is a highly invasive procedure, associated with several postoperative complications including pneumonia, anastomotic leakage, and sepsis, which may result in multiorgan failure. Pneumonia is considered a major predictor of poor long-term prognosis, so its prevention is important for patients undergoing surgery for esophageal cancer.

METHODS

The subjects of this study were 137 patients who underwent esophagectomy at Keio University Hospital, Tokyo, Japan, between January, 2012 and December, 2016. Patients who underwent R0 or R1 resection or esophagectomy with organ excision were included. Patients who underwent salvage surgery or resection of recurrent laryngeal nerve, and those with preoperative recurrent laryngeal nerve palsy, were excluded. We investigated the effect of the maximum phonation time on the development of postoperative pneumonia.

RESULTS

Pneumonia developed more frequently in patients with a long operative time, clinically left recurrent nerve lymph node metastasis, and a short preoperative maximum phonation time (p = 0.074, 0.046, and 0.080, respectively). Pneumonia was also more common in men with an abnormal maximum phonation time (p = 0.010).

CONCLUSIONS

The maximum phonation time is a significant predictor of postoperative pneumonia after esophagectomy in men.

The Effects of Exercise in Patients with Sarcopenia

The aim of this study was to assess the effects of different types of exercise interventions for treating sarcopenia compared to no specific treatment, a minimal intervention (e.g., education), or another active treatment (nutritional supplements). A review was conducted of the recent English literature searching PubMed and ScienceDirect databases. Ten randomized controlled trials (RCTs) were included in this review, presenting the results of 671 sarcopenic patients. The exercise interventions were resistance training (four studies), a multimodal program (five studies, encompassing resistance training and additional exercises such as aerobic exercises, flexibility, balance and strength training), and a whole body vibration program (one study). Results show that exercise interventions could have beneficial effects in improving muscle mass, muscle strength, and physical performance in 3 months of intervention. Resistance training, added to an adequate nutrition and aerobic exercise, appeared to deliver the most positive outcome after 3 months of intervention. Types of exercise and dose-response parameters of exercise eliciting improvement warrant further investigation. Due to the significant heterogeneity in clinical trials, the current evidence provides limited guidance. Well-designed studies evaluating exercise interventions are needed before treatment guidelines can be developed.

Kampo medicine for the holistic approach to older adults with heart failure

Heart failure (HF) is a leading cause of hospitalization, morbidity, and mortality in older adults and represents a significant clinical and economic burden on the health care system. However, there are many challenges in assessing and managing HF in elderly patients, who often have coexisting multimorbidity, frailty, and malnutrition. Therefore, it is often difficult to solve these problems with Western medicine alone, and a holistic approach, including Kampo medicine, can be helpful. In particular, managing volume control and frailty by adding Kampo formulas may help improve health-related quality of life and substantially impact prognosis in HF. This review article summarizes the role of Kampo medicine for older patients with HF and frailty.

Association between sarcopenia and erectile dysfunction in older males

INTRODUCTION

In advanced age, both sarcopenia and erectile dysfunction (ED) occur with similar underlying causes through different mechanisms. In our study we investigated the association between sarcopenia and ED in older men.

METHODS

A total of 193 male patients aged 60 years and older were included in the study. The presence of sarcopenia was investigated in accordance with EWGSOP2 diagnostic criteria. For evaluation of ED, we used the 5-question International Index of Erectile Dysfunction questionnaire with categories of no ED, mild-moderate ED, and moderate-severe ED. Total testosterone levels were measured.

RESULTS

The median age of the patients was 71.9 (range 60-93 years). The prevalence of sarcopenia was 24.9%, and moderate-severe ED was 49.2%. Moderate-severe ED was more common in patients with sarcopenia than those without (70.8% vs 42.1%, p < 0.001). After adjustment for age and Charlson Comorbidity Index, the presence of sarcopenia was significantly associated with moderate-severe ED with odds ratio (OR) of 2.71 (95% Confidence Interval [CI] 1.29-5.73, p = 0.009). The components of sarcopenia were assessed separately in multivariate analysis. Muscle strength and muscle mass were significantly associated with moderate-severe ED with OR of 0.93 (95%CI 0.89-0.98) and 0.68 (95%CI 0.54-0.86), respectively, whereas gait speed was not associated with moderate-severe ED.

CONCLUSION

The presence of sarcopenia in older men is associated with an increased risk of moderate-severe ED. In addition, decreased muscle strength and decreased muscle mass are associated with an increased risk of moderate-severe ED. Prospective studies are needed to reveal the causality between sarcopenia and ED.

Aging Aggravates Cachexia in Tumor-Bearing Mice

Simple Summary

Cachexia is a deadly disease that accompanies many different types of cancers. Animal studies on cachexia have so far mostly been conducted using young mice, while cancer in humans is a disease of high age. Mouse models used to date may therefore not be suitable to study cachexia with relevance to patients. By comparing young and old mice of three different strains and two different tumor types, we here show that the age of mice has a substantial effect on cachexia progression (specifically body weight, tissue weight, fiber size, molecular markers) that is dependent on the mouse strain studied. This is independent of glucose tolerance. The cachexia markers IL6 and GDF15 differ between ages in both mice and patients. Future studies on cachexia should consider the age and strain of mice.

Abstract

Background: Cancer is primarily a disease of high age in humans, yet most mouse studies on cancer cachexia are conducted using young adolescent mice. Given that metabolism and muscle function change with age, we hypothesized that aging may affect cachexia progression in mouse models. Methods: We compare tumor and cachexia development in young and old mice of three different strains (C57BL/6J, C57BL/6N, BALB/c) and with two different tumor cell lines (Lewis Lung Cancer, Colon26). Tumor size, body and organ weights, fiber cross-sectional area, circulating cachexia biomarkers, and molecular markers of muscle atrophy and adipose tissue wasting are shown. We correlate inflammatory markers and body weight dependent on age in patients with cancer. Results: We note fundamental differences between mouse strains. Aging aggravates weight loss in LLC-injected C57BL/6J mice, drives it in C57BL/6N mice, and does not influence weight loss in C26-injected BALB/c mice. Glucose tolerance is unchanged in cachectic young and old mice. The stress marker GDF15 is elevated in cachectic BALB/c mice independent of age and increased in old C57BL/6N and J mice. Inflammatory markers correlate significantly with weight loss only in young mice and patients. Conclusions: Aging affects cachexia development and progression in mice in a strain-dependent manner and influences the inflammatory profile in both mice and patients. Age is an important factor to consider for future cachexia studies.

Evaluation of Dynapenia and Sarcopenia and Their Associations With Serum Insulin-Like Growth Factor-1 Levels in Renal Transplant Recipients

OBJECTIVES

Dynapenia and sarcopenia are related to increased morbidity and mortality in the general population. Chronic kidney disease (CKD) causes sarcopenia and dynapenia with different mechanisms. The aim of this study is to compare the muscle parameters in renal transplant recipients to CKD patients and patients without kidney disease and assess their associations with serum insulin-like growth factor-1 (IGF-1) levels.

METHOD

In total, 120 renal transplant recipients (mean age: 40.4 ± 10.5 years), 60 CKD patients (mean age: 41.9 ± 11.4 years), and 60 control subjects with normal kidney function (mean age: 38.8 ± 9.9 years) were enrolled. Body mass index, hand grip strength, bioelectrical impedance analysis, 6-minute walking test, and serum IGF-1 level were measured and compared between groups. Muscle parameters were evaluated according to The Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia Project criteria.

RESULTS

IGF-1 levels were highest in the renal transplantation group and lowest in the control group (P = .029). In total, 12.5% of patients in the renal transplantation group (13.3% overweight, 20% obese), 11.6% in the CKD group, and 1.6% in the control group had dynapenia (P = .015). In addition, 8.3% of patients in the CKD group, 3.3% in the renal transplantation group (50% overweight), and none of the patients in the control group had sarcopenia (P = .054). In multivariate analyses, muscle strength was associated with IGF-1 levels in renal transplant recipients (beta = 2.314, t = 3.456, P = .001).

CONCLUSIONS

Serum IGF-1 is closely associated with muscle strength in renal transplant recipients. The negative effects of CKD on muscle system cannot be completely resolved with renal transplantation. Sarcopenic obesity and dynapenic obesity need special attention and therefore body mass index cannot be used as the only parameter to evaluate frailty in renal transplant recipients.

Modeling Functional Limitations, Gait Impairments, and Muscle Pathology in Alzheimer's Disease: Studies in the 3xTg-AD Mice

Gait impairments in Alzheimer's disease (AD) result from structural and functional deficiencies that generate limitations in the performance of activities and restrictions in individual's biopsychosocial participation. In a translational way, we have used the conceptual framework proposed by the International Classification of Disability and Health Functioning (ICF) to classify and describe the functioning and disability on gait and exploratory activity in the 3xTg-AD animal model. We developed a behavioral observation method that allows us to differentiate qualitative parameters of psychomotor performance in animals' gait, similar to the behavioral patterns observed in humans. The functional psychomotor evaluation allows measuring various dimensions of gait and exploratory activity at different stages of disease progression in dichotomy with aging. We included male 3xTg-AD mice and their non-transgenic counterpart (NTg) of 6, 12, and 16 months of age (n = 45). Here, we present the preliminary results. The 3xTg-AD mice show more significant functional impairment in gait and exploratory activity quantitative variables. The presence of movement limitations and muscle weakness mark the functional decline related to the disease severity stages that intensify with increasing age. Motor performance in 3xTg-AD is accompanied by a series of bizarre behaviors that interfere with the trajectory, which allows us to infer poor neurological control. Additionally, signs of physical frailty accompany the functional deterioration of these animals. The use of the ICF as a conceptual framework allows the functional status to be described, facilitating its interpretation and application in the rehabilitation of people with AD.

Using accelerometers in the assessment of sarcopenia in older adults attending a day hospital service in Ireland

Objectives:

The aim of this study was to describe the associations between sarcopenia and variables derived from wrist accelerometry in community-dwelling older adults attending a day hospital service in Ireland.

Methods:

An observational cross-sectional study was carried out using a consecutive series of older adults attending a day hospital service. Sarcopenia was diagnosed using the latest European Working Group of Sarcopenia in Older People guidelines. Accelerometers were worn by each participant for a 7-day period on their non-dominant wrist.

Results:

Thirty-eight out of forty-one participants (93%) met the accelerometer wear time criterion and were included in statistical analyses. Included participants had a mean age of 81.1 years (standard deviation 6.2). Both sarcopenia (Grip) and sarcopenia (Lower limb) were associated with increased time spent in low physical activity and reduced average of Kcals per hour. Only sarcopenia (Lower limb) was associated with increased time in sedentary behaviour as well as reduced number of steps taken in a week.

Conclusions:

Accelerometer data can be used in an older day hospital population to track physical activity levels and sedentary behaviours. The assessment tool used to assess muscle strength and the cut-off criteria for physical activity behaviour influences the association with sarcopenia.

Transgenic Expression of Bmp3b in Mesenchymal Progenitors Mitigates Age-Related Muscle Mass Loss and Neuromuscular Junction Degeneration

Skeletal muscle is a vital organ for a healthy life, but its mass and function decline with aging, resulting in a condition termed sarcopenia. The etiology of sarcopenia remains unclear. We recently demonstrated that interstitial mesenchymal progenitors are essential for homeostatic muscle maintenance, and a diminished expression of the mesenchymal-specific gene Bmp3b is associated with sarcopenia. Here, we assessed the protective function of Bmp3b against sarcopenia by generating conditional transgenic (Tg) mice that enable a forced expression of Bmp3b specifically in mesenchymal progenitors. The mice were grown until they reached the geriatric stage, and the age-related muscle phenotypes were examined. The Tg mice had significantly heavier muscles compared to control mice, and the type IIB myofiber cross-sectional areas were preserved in Tg mice. The composition of the myofiber types did not differ between the genotypes. The Tg mice showed a decreasing trend of fibrosis, but the degree of fat infiltration was as low as that in the control mice. Finally, we observed the preservation of innervated neuromuscular junctions (NMJs) in the Tg muscle in contrast to the control muscle, where the NMJ degeneration was conspicuous. Thus, our results indicate that the transgenic expression of Bmp3b in mesenchymal progenitors alleviates age-related muscle deterioration. Collectively, this study strengthens the beneficial role of mesenchymal Bmp3b against sarcopenia and suggests that preserving the youthfulness of mesenchymal progenitors may be an effective means of combating sarcopenia.

Dulaglutide improves muscle function by attenuating inflammation through OPA-1-TLR-9 signaling in aged mice

Dulaglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, is widely used to treat diabetes. However, its effects on muscle wasting due to aging are poorly understood. In the current study, we investigated the therapeutic potential and underlying mechanism of dulaglutide in muscle wasting in aged mice. Dulaglutide improved muscle mass and strength in aged mice. Histological analysis revealed that the cross-sectional area of the tibialis anterior (TA) in the dulaglutide-treated group was thicker than that in the vehicle group. Moreover, dulaglutide increased the shift toward middle and large-sized fibers in both young and aged mice compared to the vehicle. Dulaglutide increased myofiber type I and type IIa in young (18.5% and 8.2%) and aged (1.8% and 19.7%) mice, respectively, compared to the vehicle group. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), a master regulator of mitochondrial biogenesis, decreased but increased by dulaglutide in aged mice. The expression of atrophic factors such as myostatin, atrogin-1, and muscle RING-finger protein-1 was decreased in aged mice, whereas that of the myogenic factor, MyoD, was increased in both young and aged mice following dulaglutide treatment. In aged mice, optic atrophy-1 (OPA-1) protein was decreased, whereas Toll-like receptor-9 (TLR-9) and its targeting inflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]) were elevated in the TA and quadriceps (QD) muscles. In contrast, dulaglutide administration reversed this expression pattern, thereby significantly attenuating the expression of inflammatory cytokines in aged mice. These data suggest that dulaglutide may exert beneficial effects in the treatment of muscle wasting due to aging.

Follistatin-induced muscle hypertrophy in aged mice improves neuromuscular junction innervation and function

Sarcopenia, or age-related loss of muscle mass and strength, is an important contributor to loss of physical function in older adults. The pathogenesis of sarcopenia is likely multifactorial, but recently the role of neurological degeneration, such as motor unit loss, has received increased attention. Here, we investigated the longitudinal effects of muscle hypertrophy (via overexpression of human follistatin, a myostatin antagonist) on neuromuscular integrity in C57BL/6J mice between the ages of 24 and 27 months. Following follistatin overexpression (delivered via self-complementary adeno-associated virus subtype 9 injection), muscle weight and torque production were significantly improved. Follistatin treatment resulted in improvements of neuromuscular junction innervation and transmission but had no impact on age-related losses of motor units. These studies demonstrate that follistatin overexpression-induced muscle hypertrophy not only increased muscle weight and torque production but also countered age-related degeneration at the neuromuscular junction in mice.

Common Muscle Metabolic Signatures Highlight Arginine and Lysine Metabolism as Potential Therapeutic Targets to Combat Unhealthy Aging

Biological aging research is expected to reveal modifiable molecular mechanisms that can be harnessed to slow or possibly reverse unhealthy trajectories. However, there is first an urgent need to define consensus molecular markers of healthy and unhealthy aging. Established aging hallmarks are all linked to metabolism, and a ‘rewired’ metabolic circuitry has been shown to accelerate or delay biological aging. To identify metabolic signatures distinguishing healthy from unhealthy aging trajectories, we performed nontargeted metabolomics on skeletal muscles from 2-month-old and 21-month-old mice, and after dietary and lifestyle interventions known to impact biological aging. We hypothesized that common metabolic signatures would highlight specific pathways and processes promoting healthy aging, while revealing the molecular underpinnings of unhealthy aging. Here, we report 50 metabolites that commonly distinguished aging trajectories in all cohorts, including 18 commonly reduced under unhealthy aging and 32 increased. We stratified these metabolites according to known relationships with various aging hallmarks and found the greatest associations with oxidative stress and nutrient sensing. Collectively, our data suggest interventions aimed at maintaining skeletal muscle arginine and lysine may be useful therapeutic strategies to minimize biological aging and maintain skeletal muscle health, function, and regenerative capacity in old age.

Association between protoporphyrin IX and sarcopenia: a cross sectional study

Background

According to the European Working Group on Sarcopenia in Older People (EWGSOP), the diagnosis of sarcopenia primarily focused on low muscle strength with the detection of low muscle quality and quantity as confirming index. Many studies had identified mitochondrial dysfunction as one of the multifactorial etiologies of sarcopenia. Yet, no study had investigated the role of biosynthetic pathway intermediate, which was found in mitochondria, in the development of sarcopenia. This study aimed to examine the association between protoporphyrin IX (PPIX) and components of sarcopenia.

Method

The present study enrolled 1172 participants without anemia between 1999 to 2002 from the National Health and Nutrition Examination Survey (NHANES) database. We employed the multivariable-logistic regression model to examine the relationship between PPIX and sarcopenia. Covariate adjustments were designated to each of the three models for further analysis of the relationship.

Results

In the unadjusted model, PPIX was significantly associated with sarcopenia (OR = 3.910, 95% CI = 2.375, 6.439, P value < 0.001). The significance persisted after covariate adjustments as observed in the fully adjusted model (OR = 2.537, 95% CI = 1.419, 4.537, P value = 0.002).

Conclusions

The findings of this study suggested statistically significant association between PPIX and sarcopenia. Our study disclosed the potential of PPIX as a valuable indicator of sarcopenia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02331-6.

Curative Radiotherapy in Elderly Patients With Muscle Invasive Bladder Cancer: The Prognostic Role of Sarcopenia

BACKGROUND/AIM

To evaluate the impact of sarcopenia in muscle invasive bladder cancer (MIBC) elderly patients submitted to curative radiotherapy.

PATIENTS AND METHODS

Patients received radiotherapy between 2013 and 2018, and the skeletal muscle index was calculated to classify them as sarcopenic or non-sarcopenic. Primary endpoints were overall survival (OS), cancer specific survival (CSS), 90-day mortality and toxicity.

RESULTS

A total of 28 patients with a median age of 85 years met our inclusion criteria and 8 of them were sarcopenic. With a median prescribed dose of 61 Gy and a median follow-up of 24.5 months, OS rates in the sarcopenic and non-sarcopenic groups were 100% and 84.4% at 3 months, 57.1% and 56.6% at 12 months, 38.1% and 50.3% at 24 months and 38.1% and 33.5% at 48 months, respectively; the CSS rates were 100% and 94.1% at 3 months and 68.6% and 88.2% at 12, 24 and 48 months, respectively. The actuarial 90-day mortality rate was 17.9% for the whole cohort, and 20% and 12.5% for the non-sarcopenic and sarcopenic groups, respectively. The radio-induced toxicity was similar in both groups.

CONCLUSION

Sarcopenia cannot be considered a negative prognostic factor for MIBC elderly patients treated with external beam radiotherapy. Irradiation is therefore a feasible and effective choice for these patients, especially if unfit for surgery.

Low Grip Strength Associated with Clinical Outcomes after Total Hip Arthroplasty - A Prospective Case-Control Study

OBJECTIVE

To assess whether low grip strength (GS) is associated with clinical outcomes after total hip arthroplasty (THA).

METHODS

A prospective case-control study was designed to assess 231 cases of primary THA between January 1, 2015 to May 1, 2018, at an urban tertiary care hospital. Patients were placed into two cohorts based on preoperative GS levels. Low GS in the present study was defined as GS lower than 26 kg for men and 16 kg for women in the dominant hand. Baseline data were prospectively collected and included patient demographics (age, sex, body mass index [BMI]), the surgeon's diagnoses, medical history, length of stay, and American Society of Anaesthesiologists' (ASA) score. Clinical outcomes included surgery- and prosthesis-related variables. The Harris hip score (HHS) and the Short Form Health Survey (SF-12) were completed at the baseline visit and at 1 and 2 years postoperatively in the outpatient department to assess the hip's function and quality of life. Differences in baseline data, length of study (LOS), 90-day postoperative complications, and hospital readmissions were compared. Besides, the correlations between GS and Harris hip score (HHS) and Short Form score (SF-12) were tested.

RESULTS

A total of 202 participants have completed records for analysis finally. The patients were followed up for an average of 24.8 months postoperatively (24-26 months). Eighty-two patients (40.6%) had low GS before THA. Patients with low GS were more likely to be female, older, fracture of femoral head or neck as the primary cause, albumin <3.5 g/dL, and have a lower BMI, higher ASA score, increased rates of the pressure sore, blood transfusion, and LOS compared to normal GS (all P < 0.05). Also, patients in the low GS cohort showed a statistically significant increased unplanned hospital readmissions and decreased discharge home compared to normal GS (both P < 0.05). There was an increasing rate of complications between the two cohorts, for cardiac complications, pressure sore after THA, respiratory complications, urinary tract infection, stroke, and DVT (all P < 0.05). A partial correlation test by controlling medical comorbidities and demographic factors was used to determine the correlation between GS and HHS. There was a significant correlation between them (r = -0.673; P = 0.002). A similar condition was detected in the correlation between GS and SF-12 (r = 0.645; P = 0.001).

CONCLUSIONS

Clinicians should be encouraged to include GS assessment in their evaluation of patients who planned to undergo THA in order to optimize the treatment of high-risk individuals.

Voluntary wheel running with and without follistatin overexpression improves NMJ transmission but not motor unit loss in late life of C57BL/6J mice

Sarcopenia, or pathological loss of muscle mass and strength during aging, is an important contributor to loss of physical function in older adults. Sarcopenia is a multifactorial syndrome associated with intrinsic muscle and upstream neurological dysfunction. Exercise is well-established as an effective intervention for sarcopenia, but less is known about the long-term neurobiological impact of exercise. The goals of this study were to investigate the effects of exercise, alone or in combination with follistatin (FST) overexpression (antagonist of myostatin), on neuromuscular junction transmission and motor unit numbers in mice between the age of 22 and 27 months, ages at which prior studies have demonstrated that some motor unit loss is already evident. C57BL/6J mice underwent baseline assessment and were randomized to housing with or without voluntary running wheels and injection with adeno-associated virus to overexpress FST or vehicle. Groups for comparison included sedentary and running with and without FST. Longitudinal assessments showed significantly increased muscle mass and contractility in the 'running plus FST' group, but running, with and without FST, showed no effect on motor unit degeneration. In contrast, running, with and without FST, demonstrated marked improvement of neuromuscular junction transmission stability.

Sarcopenia, obesity, osteoporosis and old age

Modern concepts about body composition in the elderly are described in the review. Particular attention is paid to possible causes and pathogenetic aspects of sarcopenia, as well as modern diagnostic approaches to its recognition. The ageing process is inevitably combined with diverse changes in body composition. This age-related evolution can be described by three main processes: a decrease in the growth and mineral density of bone tissue (osteopenia and osteoporosis); progressive decrease in muscle mass; an increase in adipose tissue (sarcopenia and sarcopenic obesity) with its redistribution towards central and visceral fat accumulation. Sarcopenia and osteoporosis are considered the main geriatric syndromes. These pathological conditions contribute to a significant decrease in the quality of life in the elderly; create conditions for the loss of independence and require long-term care, increase the frequency of hospitalizations and ultimately result in adverse outcomes.

The biphasic and age-dependent impact of klotho on hallmarks of aging and skeletal muscle function

Aging is accompanied by disrupted information flow, resulting from accumulation of molecular mistakes. These mistakes ultimately give rise to debilitating disorders including skeletal muscle wasting, or sarcopenia. To derive a global metric of growing 'disorderliness' of aging muscle, we employed a statistical physics approach to estimate the state parameter, entropy, as a function of genes associated with hallmarks of aging. Escalating network entropy reached an inflection point at old age, while structural and functional alterations progressed into oldest-old age. To probe the potential for restoration of molecular 'order' and reversal of the sarcopenic phenotype, we systemically overexpressed the longevity protein, Klotho, via AAV. Klotho overexpression modulated genes representing all hallmarks of aging in old and oldest-old mice, but pathway enrichment revealed directions of changes were, for many genes, age-dependent. Functional improvements were also age-dependent. Klotho improved strength in old mice, but failed to induce benefits beyond the entropic tipping point.

Muscle Proteomic and Transcriptomic Profiling of Healthy Aging and Metabolic Syndrome in Men

(1) Background: Aging is associated with a progressive decline in muscle mass and function. Aging is also a primary risk factor for metabolic syndrome, which further alters muscle metabolism. However, the molecular mechanisms involved remain to be clarified. Herein we performed omic profiling to decipher in muscle which dominating processes are associated with healthy aging and metabolic syndrome in old men. (2) Methods: This study included 15 healthy young, 15 healthy old, and 9 old men with metabolic syndrome. Old men were selected from a well-characterized cohort, and each vastus lateralis biopsy was used to combine global transcriptomic and proteomic analyses. (3) Results: Over-representation analysis of differentially expressed genes (ORA) and functional class scoring of pathways (FCS) indicated that healthy aging was mainly associated with upregulations of apoptosis and immune function and downregulations of glycolysis and protein catabolism. ORA and FCS indicated that with metabolic syndrome the dominating biological processes were upregulation of proteolysis and downregulation of oxidative phosphorylation. Proteomic profiling matched 586 muscle proteins between individuals. The proteome of healthy aging revealed modifications consistent with a fast-to-slow transition and downregulation of glycolysis. These transitions were reduced with metabolic syndrome, which was more associated with alterations in NADH/NAD+ shuttle and β-oxidation. Proteomic profiling further showed that all old muscles overexpressed protein chaperones to preserve proteostasis and myofiber integrity. There was also evidence of aging-related increases in reactive oxygen species but better detoxifications of cytotoxic aldehydes and membrane protection in healthy than in metabolic syndrome muscles. (4) Conclusions: Most candidate proteins and mRNAs identified herein constitute putative muscle biomarkers of healthy aging and metabolic syndrome in old men.