If my muscle could talk: Myokines as a biomarker of frailty

Effects of resistance training associated with a verbal fluency task on physical performance and cognitive function in frail nursing home residents

OBJECTIVES

Studies examining the effects of dual-task resistance training (RT) on nursing-home residents are still scarce. To add knowledge to this field, the present study compared the effects of 12-week RT and RT plus cognitive task (COG) programs on physical performance and cognitive function in a sample of frail nursing home residents.

METHODS

This is an experimental study that combined data from two studies that examined older adults living in nursing home residences in Brazil. Exercise groups performed a 12-week RT protocol that included four exercises, with 3-4 times (sets) of 8-10 repetitions at 70 %-75 % of 1-repetition maximum (1RM), twice a week. The RT+COG group evoked as many words was possible for specific categories during concentric actions of the squat on the chair (until 90° knee flexion) and seated unilateral knee extension exercises. Global cognitive function and physical performance were evaluated using the Mini-Mental State Examination (MMSE) and Short Physical Performance Battery (SPPB) tests, respectively.

RESULTS

After interventions, participants in the RT+COG and RT groups had significantly greater lower-limb muscle strength compared with the control group (CG). Those in the RT+COG group had greater tandem performance in comparison to RT and CG groups.

CONCLUSIONS

Our findings indicate that RT preserves lower-limb muscle strength in frail nursing home residents, regardless of performance of cognitive tasks. Better balance was exclusively observed in the RT+COG, whereas significant improvements in mobility status were only found in the RT group. The present investigation was based on a small sample of nursing home residents. Larger and more structured studies are necessary to confirm our results.

The Significance of Selected Myokines in Predicting the Length of Rehabilitation of Patients after COVID-19 Infection

In the context of the global COVID-19 pandemic, understanding the intricate mechanisms of the body's response to infection and inflammation has become a priority for the medical and research communities. It has been proven that during COVID-19 infection, molecules are secreted-namely organokines, which may directly or indirectly play a role in the pathophysiology of COVID-19. The objective of this study was to scrutinize the potential correlation between the levels of selected myokines (myostatin, agrin, irisin, and myonectin) and the duration of rehabilitation in post-COVID-19 patients. Additionally, the study aimed to investigate whether there is a correlation between the levels of these myokines and the length of hospitalization during COVID-19 treatment. The study was conducted at the Rehabilitation Hospital in Szczecin (Poland). Patients in the study participated in a comprehensive rehabilitation program following COVID-19 treatment. In order to assess the effectiveness of rehabilitation, the following tests were performed: a 6 min walk test with an assessment of exercise tolerance (Borg scale), an assessment of dyspnea severity (mMRC scale), a spirometric assessment of respiratory function, a measurement of arm strength, and an assessment of fatigue using the Fatigue Assessment Scale (FAS). Myokine levels were measured using commercially available enzyme-linked immunosorbent assays (ELISA) according to the manufacturer's instructions. Statistical analysis was performed using Statistica 13.1 software. Lower concentrations of irisin and myonectin and higher concentrations of myostatin correlated with longer rehabilitation time. Baseline levels of specific myokines in post-COVID-19 patients could play a crucial role in anticipating the duration of rehabilitation. The duration of hospitalization for the infection may influence myokine levels in patients recovering from COVID-19.

Myokines: A central point in managing redox homeostasis and quality of life

Redox homeostasis is a crucial phenomenon that is obligatory for maintaining the healthy status of cells. However, the loss of redox homeostasis may lead to numerous diseases that ultimately result in a compromised quality of life. Skeletal muscle is an endocrine organ that secretes hundreds of myokines. Myokines are peptides and cytokines produced and released by muscle fibers. Skeletal muscle secreted myokines act as a robust modulator for regulating cellular metabolism and redox homeostasis which play a prime role in managing and improving metabolic function in multiple organs. Further, the secretory myokines maintain redox homeostasis not only in muscles but also in other organs of the body via stabilizing oxidants and antioxidant levels. Myokines are also engaged in maintaining mitochondrial dynamics as mitochondria is a central point for the generation of reactive oxygen species (ROS). Ergo, myokines also act as a central player in communicating signals to other organs, including the pancreas, gut, liver, bone, adipose tissue, brain, and skin via their autocrine, paracrine, or endocrine effects. The present review provides a comprehensive overview of skeletal muscle-secreted myokines in managing redox homeostasis and quality of life. Additionally, probable strategies will be discussed that provide a solution for a better quality of life.

Physical performance and negative events in very old adults: a longitudinal study examining the ilSIRENTE cohort

BACKGROUND

Declining physical performance in old age is associated with a wide range of negative health-related outcomes. However, it is unclear which physical capabilities should be prioritized to obtain prognostic information in older adults.

AIMS

To examine the associations between the performance on several physical function tests and falls, disability, and death in a well-characterized sample of very old Italian adults.

METHODS

This was a prospective cohort study of older adults who lived in the mountain community of the Sirente geographic area in Central Italy. Physical performance was assessed using isometric handgrip strength (IHG), walking speed (WS) at a usual and fast pace, 5-time sit-to-stand test (5STS), and sit-to-stand power measures. Appendicular skeletal muscle mass was estimated from calf circumference using a validated equation. History of falls, incident falls, and disability status according to basic Activities of Daily Living (ADLs) were recorded over two years. Survival status was obtained from the participants' general practitioners and was confirmed by the National Death Registry over 10 years from enrolment. Linear, binary, and Cox regressions were performed to evaluate the association between physical performance measures and health outcomes.

RESULTS

The mean age of the 255 participants was 84.2 ± 5.1 years, and 161 (63.1%) were women. Logistic regression indicated that IHG was significantly associated with incident ADL disability, whereas specific sit-to-stand muscle power was an independent predictor of death. No significant associations were observed between physical function and falls.

CONCLUSIONS

Our findings indicate selective associations between physical function tests and the occurrence of negative events in very old adults, with poor IHG predicting disability and specific sit-to-stand muscle power being longitudinally associated with death.

Mitochondrial Quantity and Quality in Age-Related Sarcopenia

Sarcopenia, the age-associated decline in skeletal muscle mass and strength, is a condition with a complex pathophysiology. Among the factors underlying the development of sarcopenia are the progressive demise of motor neurons, the transition from fast to slow myosin isoform (type II to type I fiber switch), and the decrease in satellite cell number and function. Mitochondrial dysfunction has been indicated as a key contributor to skeletal myocyte decline and loss of physical performance with aging. Several systems have been implicated in the regulation of muscle plasticity and trophism such as the fine-tuned and complex regulation between the stimulator of protein synthesis, mechanistic target of rapamycin (mTOR), and the inhibitor of mTOR, AMP-activated protein kinase (AMPK), that promotes muscle catabolism. Here, we provide an overview of the molecular mechanisms linking mitochondrial signaling and quality with muscle homeostasis and performance and discuss the main pathways elicited by their imbalance during age-related muscle wasting. We also discuss lifestyle interventions (i.e., physical exercise and nutrition) that may be exploited to preserve mitochondrial function in the aged muscle. Finally, we illustrate the emerging possibility of rescuing muscle tissue homeostasis through mitochondrial transplantation.

Bibliometric and scientometric analysis on biomarkers and molecular mechanisms for physical frailty and sarcopenia

Introduction

The influence of physical frailty and sarcopenia (PFS) on the well-being of older people and continuous pressure on the healthcare systems has prompted a research on the pathophysiology and molecular mechanisms of these conditions. Nonetheless some biomarkers have been suggested as potential markers for PFS none of them have been shown to highlight the complex nature of PFS, which reveals that there is a need for an understanding of the possible biomarker candidates. The aim of this study was to identify the current research hotspots, status, and trends in the field of biomarkers and molecular mechanisms for PFS.

Methods

The bibliometric and scientometric analyses were performed using VOSviewer (version 1.6.18) and open source software platform Cytoscape v.3.9 (for visualizing and constructing a network of keywords). Data of publications (from 1997 to 2023) related to biomarkers and molecular mechanisms of PFS were obtained (in May 2023) from the database of Science Citation Index Expanded of Web of Science, Scopus, and PubMed. The keywords obtained from the Scopus database were used to perform a meaningful keyword analysis. A network of keyword relationships was build using Cytoscape.

Results

In this study, we present biomarker keywords for PFS in relation to other keywords potentially designating processes and mechanisms and reveal the biomarker identities and current contexts in which these biomarker identities are discussed.

Conclusions

Over recent years, scientific interest in the field of PFS has increased and focused on the inflammatory process and probably will be concentrated on myokines (such as cytokines and small proteins) that are synthetized and released by skeletal muscles in response to physical activity. Moreover, proteomic and genetic markers are deeply involved in PFS.

Age- and sex-specific normative values for muscle mass parameters in 18,625 Brazilian adults

Background

The present study aimed to provide age- and sex-specific normative values for muscle mass parameters in Brazilian adults.

Methods

Data pertaining to Brazilian adults (18+ years) who attended a nutritional clinical between January 2018 and July 2022 were analyzed. Muscle mass parameters were assessed using a bioimpedance digital scale (InBody 230, GBC BioMed NZ). Assessments were conducted under standard conditions, with participants refraining from physical exercise for 96 h and from eating or drinking (including water) for 8 h before evaluations.

Results

A total of 18,625 Brazilian adults were analyzed. Normative values for absolute and relative (height, m2) muscle mass and appendicular muscle mass (ASM) were calculated. In addition, specific age-related changes in muscle mass parameters were observed. In women, muscle mass peaked between the ages of 40-49 before gradually declining at an average rate of 5.7% per decade from the sixth decade of life onwards. ASM reached its peak earlier, during the third decade of life, and started to decline later, from 50 to 59 years. In contrast, absolute and ASM peaked at 40-49 years and declined from the sixth decade of life in men. Both sexes displayed a slightly greater decline in ASM than in muscle mass (13 vs. 12%).

Conclusions

The present study provides normative values for absolute and relative muscle mass and ASM in Brazilian adults. Furthermore, important specific age-related changes in muscle mass parameters were observed. These data have public health implications and might serve as a reference tool to guide health professionals.

The Role of Exercise in Cancer-Related Sarcopenia and Sarcopenic Obesity

One of the most common adverse effects of cancer and its therapeutic strategies is sarcopenia, a condition which is characterised by excess muscle wasting and muscle strength loss due to the disrupted muscle homeostasis. Moreover, cancer-related sarcopenia may be combined with the increased deposition of fat mass, a syndrome called cancer-associated sarcopenic obesity. Both clinical conditions have significant clinical importance and can predict disease progression and survival. A growing body of evidence supports the claim that physical exercise is a safe and effective complementary therapy for oncology patients which can limit the cancer- and its treatment-related muscle catabolism and promote the maintenance of muscle mass. Moreover, even after the onset of sarcopenia, exercise interventions can counterbalance the muscle mass loss and improve the clinical appearance and quality of life of cancer patients. The aim of this narrative review was to describe the various pathophysiological mechanisms, such as protein synthesis, mitochondrial function, inflammatory response, and the hypothalamic-pituitary-adrenal axis, which are regulated by exercise and contribute to the management of sarcopenia and sarcopenic obesity. Moreover, myokines, factors produced by and released from exercising muscles, are being discussed as they appear to play an important role in mediating the beneficial effects of exercise against sarcopenia.

Association of Physical Activity and Exercise with Physical Performance and Muscle Mass in Older Adults: Results from the Longevity Check-Up (Lookup) 7+ Project

Regular engagement in physical activity (PA) or physical exercise (PE) is effective at improving physical performance and body composition in older adults. Less is known about the benefits that may be obtained through combining PA with PE and whether the effects of activity habits differ between men and women. This study cross-sectionally investigated the association of PA and/or PE with physical performance and anthropometric measures in a large and relatively unselected sample of older adults enrolled in the Longevity Check-up (Lookup) 7+ project. Participants were individuals 65 years and older living in the community who were recruited in unconventional settings across Italy. Adherence to PA or PE was operationalized as involvement in light walking or various types of exercise, respectively, at least twice weekly for a minimum of 30 min per session throughout the last 12 months. Physical performance measures included handgrip strength and five-time sit-to-stand (5STS) tests. Lower-limb muscle power and appendicular skeletal muscle mass (ASM) were estimated through validated equations. We analyzed data of 4119 participants, of whom 2222 (53.4%) were women. The mean age was 72.8 ± 5.8 years in men and 72.1 ± 5.4 years in women. Regular engagement in PA + PE was reported by 139 (7.3%) men and 100 (4.5%) women. Results indicated that regular walking activity and/or PE were significantly associated with better physical performance and greater ASM with sex-specific patterns. Associations were also influenced by the type of activity, physical performance assessment tool, and anthropometric parameters. Men engaged in PA + PE performed better on the 5STS test and had greater handgrip strength, ASM, and relative and specific muscle power than those practicing either PA or PE. In women, the combination of PA and PE was associated with greater handgrip strength. The findings of this study indicate that older adults regularly practicing PA + PE had better physical performance than those who only engaged in either modality. In men, the combination of PA and PE was also associated with greater ASM.

The impact of resistance training on brain-derived neurotrophic factor and depression among older adults aged 60 years or older: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This systematic review and meta-analysis aimed to investigate the impact of resistance training on brain-derived neurotrophic factor (BDNF) and depression among older adults aged 60 years or older.

METHOD

Four electronic databases were systematically searched.

RESULTS

A total of 11 randomized controlled trials, with a pooled sample of 868 participants, met our inclusion criteria. Meta-analysis demonstrated that resistance training significantly improved circulating BDNF levels (mean difference; MD: 0.73 ng/ml; 95% CI [0.04, 1.42]; p = 0.04). Additionally, resistance training was associated with significant improvements in depression (standardized mean difference; SMD: -0.38; 95% CI [- 0.62, -0.14]; p = 0.002).

DISCUSSION

These findings suggest that resistance training may be an effective intervention for improving BDNF levels and reducing depression symptoms in older adults. Further research is needed to confirm these findings and to investigate the underlying mechanisms.

Retrospective Study Shows That Serum Levels of Chemokine CXCL10 and Cytokine GDF15 Support a Diagnosis of Sporadic Inclusion Body Myositis and Immune-Mediated Necrotizing Myopathy

The implementation of novel blood-based biomarkers is desired to reduce the diagnostic delay and burden for myositis patients. In this retrospective study, the potential of C-X-C motif chemokine ligand 10 (CXCL10) and growth differentiation factor 15 (GDF15) was explored in an established patient cohort diagnosed with immune-mediated necrotizing myopathy (IMNM; n = 21), sporadic inclusion body myositis (IBM; n = 18), overlap myositis (OM; n = 3), dermatomyositis (DM; n = 2), and anti-synthetase syndrome (ASS; n = 1), comparing these results with healthy controls (n = 10) and patients with a hereditary neuromuscular disorder (n = 14). CXCL10 and GDF15 were quantified in sera with enzyme-linked immunosorbent assays and immunolocalized in skeletal muscle tissue. In myositis patients, serum CXCL10 levels were significantly increased 9.6-fold compared to healthy controls and 4.2-fold compared to disease controls. Mean levels of CXCL10 were 929 ± 658 pg/mL of serum in IBM and 425 ± 324 pg/mL of serum in IMNM. With the threshold set to 180 pg/mL of CXCL10, myositis patients could be differentiated from healthy and disease controls with a sensitivity of 0.80 and a specificity of 0.71. Incorporating a threshold of 300 pg/mL for GDF15 reduced false negatives to two IMNM patients only. Subsets of muscle-infiltrating immune cells expressed CXCL10, and serum levels correlated with muscle inflammation grade. We propose adding circulating CXCL10 and GDF15 to the blood-based diagnostic toolkit for myositis as a valuable patient-friendly approach.

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.

Exercise-Induced Alternations of Adiponectin, Interleukin-8 and Indicators of Carbohydrate Metabolism in Males with Metabolic Syndrome

Adiponectin (ADIPO) and interleukin-8 (IL-8) are proteins that play a significant, albeit opposing, role in metabolic syndrome (MetS). The reported data on the effect of physical activity on the levels of these hormones in the population of people with MetS are conflicting. The aim of the study was to evaluate the changes in hormone concentrations, insulin-resistance indices and body composition after two types of training. The study included 62 men with MetS (age 36.6 ± 6.9 years, body fat [BF] = 37.53 ± 4.5%), randomly assigned to: an experimental group EG1 (n = 21) with aerobic exercise intervention, an experimental group EG2 (n = 21) with combined aerobic and resistance exercise intervention, both for 12 weeks, and a control group CG (n = 20) without interventions. Anthropometric measurements and body composition (fat-free mass [FFM], gynoid body fat [GYNOID]), as well as a biochemical blood analysis (adiponectin [ADIPO], interleukin-8 [IL-8], homeostatic model assessment-adiponectin (HOMA-AD) and homeostatic model assessment-triglycerides (HOMA-TG) were performed at baseline, and at 6 and 12 weeks of intervention and 4 weeks after the intervention (follow-up). Intergroup (between groups) and intragroup (within each group) changes were statistically evaluated. In the experimental groups EG1 and EG2, no significant changes were observed in the ADIPO concentration, but a decrease of GYNOID and insulin-resistance indices was confirmed. The aerobic training led to favorable changes in IL-8 concentration. The use of combined resistance and aerobic training led to improved body composition, decreased waist circumference and better insulin-resistance indices in men with MetS.

Sarcopenia and Cognitive Decline in Older Adults: Targeting the Muscle-Brain Axis

Declines in physical performance and cognition are commonly observed in older adults. The geroscience paradigm posits that a set of processes and pathways shared among age-associated conditions may also serve as a molecular explanation for the complex pathophysiology of physical frailty, sarcopenia, and cognitive decline. Mitochondrial dysfunction, inflammation, metabolic alterations, declines in cellular stemness, and altered intracellular signaling have been observed in muscle aging. Neurological factors have also been included among the determinants of sarcopenia. Neuromuscular junctions (NMJs) are synapses bridging nervous and skeletal muscle systems with a relevant role in age-related musculoskeletal derangement. Patterns of circulating metabolic and neurotrophic factors have been associated with physical frailty and sarcopenia. These factors are mostly related to disarrangements in protein-to-energy conversion as well as reduced calorie and protein intake to sustain muscle mass. A link between sarcopenia and cognitive decline in older adults has also been described with a possible role for muscle-derived mediators (i.e., myokines) in mediating muscle-brain crosstalk. Herein, we discuss the main molecular mechanisms and factors involved in the muscle-brain axis and their possible implication in cognitive decline in older adults. An overview of current behavioral strategies that allegedly act on the muscle-brain axis is also provided.

Energy metabolism and frailty: The potential role of exercise-induced myokines - A narrative review

Frailty is a complex condition that emerges from dysregulation in multiple physiological systems. Increasing evidence suggests the potential role of age-related energy dysregulation as a key driver of frailty. Exercise is considered the most efficacious intervention to prevent and even ameliorate frailty as it up-tunes and improves the function of several related systems. However, the mechanisms and molecules responsible for these intersystem benefits are not fully understood. The skeletal muscle is considered a secretory organ with endocrine functions that can produce and secrete exercise-related molecules such as myokines. These molecules are cytokines and other peptides released by muscle fibers in response to acute and/or chronic exercise. The available evidence supports that several myokines can elicit autocrine, paracrine, or endocrine effects, partly mediating inter-organ crosstalk and also having a critical role in improving cardiovascular, metabolic, immune, and neurological health. This review describes the current evidence about the potential link between energy metabolism dysregulation and frailty and provides a theoretical framework for the potential role of myokines (via exercise) in counteracting frailty. It also summarizes the physiological role of selected myokines and their response to different acute and chronic exercise protocols in older adults.

Organokines, Sarcopenia, and Metabolic Repercussions: The Vicious Cycle and the Interplay with Exercise

Sarcopenia is a disease that becomes more prevalent as the population ages, since it is directly linked to the process of senility, which courses with muscle atrophy and loss of muscle strength. Over time, sarcopenia is linked to obesity, being known as sarcopenic obesity, and leads to other metabolic changes. At the molecular level, organokines act on different tissues and can improve or harm sarcopenia. It all depends on their production process, which is associated with factors such as physical exercise, the aging process, and metabolic diseases. Because of the seriousness of these repercussions, the aim of this literature review is to conduct a review on the relationship between organokines, sarcopenia, diabetes, and other metabolic repercussions, as well the role of physical exercise. To build this review, PubMed-Medline, Embase, and COCHRANE databases were searched, and only studies written in English were included. It was observed that myokines, adipokines, hepatokines, and osteokines had direct impacts on the pathophysiology of sarcopenia and its metabolic repercussions. Therefore, knowing how organokines act is very important to know their impacts on age, disease prevention, and how they can be related to the prevention of muscle loss.

Protein intake and physical function in older adults: A systematic review and meta-analysis

BACKGROUND

The present study explored cross-sectional and longitudinal associations between protein intake and physical function in older adults.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association between protein intake and measures of physical function in older adults. Cross-sectional, case-control, and longitudinal cohort studies that investigated the association between protein intake and physical function as a primary or secondary outcome in people aged 60 + years were included. Studies published in languages other than English, Italian, Portuguese, or Spanish were excluded. Studies were retrieved from MEDLINE, SCOPUS, EMBASE, CINAHL, AgeLine, and Food Science Source databases through January 31, 2022. A pooled effect size was calculated based on standard mean differences (SMD), MD, log odds ratio (OR) and Z-score..

RESULTS

Twenty-two cross-sectional studies examined a total of 11,332 community-dwellers, hospitalized older adults, and elite senior athletes with a mean age of approximately 75 years. The pooled analysis indicated that a protein intake higher than the recommended dietary allowance (RDA) was significantly associated with higher Short Physical Performance Battery (SPPB) scores (SMD: 0.63, 95% CI: 0.27, 0.99, P-value: 0.0006), faster walking speed, greater lower-limb (SMD: 0.22, 95% CI: 0.04, 0.40, P-value: 0.02) and isometric handgrip strength (Z-score: 0.087, 95% CI: 0.046-0.128, P-value: 0.0001), and better balance (SMD: 0.33, 95% CI: 0.05, 0.62, P-value: 0.02). Nine longitudinal studies investigated 12,424 community-dwelling and native older adults with a mean age of approximately 85 years. A protein intake higher than the current RDA was not associated with lower decline in either isometric handgrip strength (logOR: 0.99, 95% CI: 0.97-1.02, P-value= 0.67) or walking speed (logOR: 0.92, 95% CI: 0.77-1.10, P-value= 0.35).

CONCLUSIONS

A protein intake higher than the RDA is cross-sectionally associated with better physical performance and greater muscle strength in older adults. However, a high consumption of proteins does not seem to prevent physical function decline over time.

Identification of Coenzyme Q10 and Skeletal Muscle Protein Biomarkers as Potential Factors to Assist in the Diagnosis of Sarcopenia

The aim of this study was to explore the use of coenzyme Q10 and skeletal muscle protein biomarkers in the diagnosis of sarcopenia. Subjects with or without sarcopenia were recruited. The anthropometric, muscle strength and endurance measurements were assessed. Muscle proteins (albumin and creatine kinase), myokines (irisin and myostatin), and the coenzyme Q10 level were measured. Approximately half of the subjects suffered from a low coenzyme Q10 concentration (<0.5 μM). The levels of creatinine kinase and irisin were significantly lower in subjects with sarcopenia (p ≤ 0.05). In receiver operating characteristic analyses, irisin and creatine kinase showed a better prediction capability for sarcopenia (area under the curve, irisin: 0.64 vs. creatinine kinase: 0.61) than other biomarkers. Additionally, a low level of irisin (<118.0 ng/mL, odds ratio, 6.46, p < 0.01), creatine kinase (<69.5 U/L, odds ratio, 3.31, p = 0.04), or coenzyme Q10 (<0.67 μM, odds ratio, 9.79, p < 0.01) may increase the risk for sarcopenia even after adjusting for confounders. Since the levels of coenzyme Q10 and muscle biomarkers, such as irisin and creatine kinase, are associated with sarcopenia, we suggest they could be used as candidate markers to assist in the diagnosis of sarcopenia.

Resistance training improves cognitive function in older adults with different cognitive status: a systematic review and Meta-analysis

The present study investigated the impact of resistance training (RT) on cognitive function in older adults with different cognitive status by conducting a systematic review and meta-analysis of intervention studies. We performed a literature search with no restriction on publication year in MEDLINE, Embase, CINAHL, SPORTDiscus, and AgeLine from inception up to August 2020. Experimental studies investigating the impact of RT on the cognitive function of cognitively healthy (CH) and cognitively impaired (CI) older adults (≥60 years) were included for analysis. Eighteen studies were included in the final analysis, of which ten studies investigated CH community-dwelling older adult, seven studies investigated CI older adults, and one study investigated both. RT significantly improved overall cognitive function in both CH (SMD = 0.54; 95% CI = 0.00 to 1.08, P = 0.047) and CI (SMD = 0.60; 95% CI = 0.21 to 1.16, P = 0.005) older adults. However, short-term memory was only improved in CH older adults (MD = -0.20; 95% CI = -0.25 to -0.15, P < 0.00001). In conclusion, RT improved overall cognitive function in CH and CI older adults, whereas short-term memory, assessed by the digit span of the WAIS III, was only significantly improved in CH older adults.

Biomarkers shared by frailty and sarcopenia in older adults: A systematic review and meta-analysis

BACKGROUND

Physical frailty and sarcopenia show extensive clinical similarities. Whether biomarkers exist that are shared by the two conditions is presently unclear.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association of frailty and/or sarcopenia with biomarkers as a primary or secondary outcome in adults aged 60 years and older. Only studies published in English that defined frailty using a validated scale and/or questionnaire and diagnosed sarcopenia according to the presence of muscle atrophy plus dynapenia or low physical function were included. Studies were identified from a systematic search of MEDLINE and SCOPUS databases from inception through August 2020. The quality of reporting of each study was assessed by using the Quality Assessment Tool for Observational Cohort, Cross-Sectional and Case-Control studies of the National Institute of Health. A meta-analysis was conducted when at least three studies investigated the same biomarker in both frailty and sarcopenia. Pooled effect size was calculated based on standard mean differences and random-effect models. Sensitivity analysis was performed based on age and the setting where the study was conducted.

RESULTS

Eighty studies (58 on frailty and 22 on sarcopenia) met the inclusion criteria and were included in the qualitative analysis. Studies on frailty included 33,160 community-dwellers, hospitalized, or institutionalized older adults (60-88 years) from 21 countries. Studies on sarcopenia involved 4904 community-living and institutionalized older adults (68-87.6 years) from 9 countries. Several metabolic, inflammatory, and hematologic markers were found to be shared between the two conditions. Albumin and hemoglobin were negatively associated with both frailty and sarcopenia. Interleukin 6 was associated with frailty and sarcopenia only in people aged < 75. Community-dwelling older adults with frailty and sarcopenia had higher levels of tumor necrosis factor alpha compared with their robust and non-sarcopenic counterparts.

CONCLUSIONS

A set of metabolic, hematologic, and inflammatory biomarkers was found to be shared by frailty and sarcopenia. These findings fill a knowledge gap in the quest of biomarkers for these conditions and provide a rationale for biomarker selection in studies on frailty and sarcopenia.

Obesity phenotypes are, in part, associated with physical activity in diabetic hemodialysis patients

PURPOSE

To investigate the prevalence of obesity phenotypes and their association with physical activity levels among diabetic hemodialysis patients.

METHODS

This is a cross-sectional study with 84 diabetic hemodialysis patients (63.5 ± 9.4 years, 54.8% of men). Obesity was diagnosed as high body fat (≥ 40% for male and ≥ 30% for female). Sarcopenic obesity was considered if low skeletal muscle mass (< 20.0 kg for males and < 15.0 kg for females) and obesity were combined. Dynapenic obesity was defined in the presence of low handgrip strength (< 27 kg for males and < 16 kg for females) and obesity. Muscle failure obesity was confirmed in the concomitant presence of obesity, sarcopenia, and dynapenia. Physical activity level was assessed by the Baecke questionnaire and patients were classified as low physical activity according to the first tertile for each of and total domains.

RESULTS

Fifty-four patients (64%) presented obesity. From these, 5 (6%), 19 (23%) and 8 (10%) were classified as sarcopenic obese, dynapenic obese, and muscle failure obese, respectively, and 22 (26%) were only obese. Patients with sarcopenic obesity and muscle failure obesity had lower leisure and locomotion physical activity scores than non-obese, whereas the total domain score did not differ across the groups. Muscle failure obesity was independently associated with low leisure physical activity (OR 10.8, 95% CI 1.3-88.1). Only sarcopenic obesity was independently associated with the locomotion and total physical activity domains (OR 15.4, 95% CI 1.4-90.2 and OR 17.0, 95% CI 1.5-95.4, respectively).

CONCLUSION

Our study found a lower prevalence of sarcopenic obesity compared to dynapenic obesity and muscle failure obesity among diabetic hemodialysis patients. Moreover, sarcopenic obesity and muscle failure obesity, but not dynapenic obesity, were associated with low physical activity levels.

Evidence-based recommendations for resistance and power training to prevent frailty in community-dwellers

Frailty is a reversible state of reduced resilience to stressful events resulting from a multisystem impairment of the human body. As frailty progresses, people become more vulnerable to numerous adverse events, including falls and fractures, cognitive decline, disability, hospitalization, nursing home placement, and death. As such, substantial health care costs are associated with frailty. These features have led to the recognition of frailty as a public health problem. The identification of strategies for the management of frailty has, therefore, become a topic of extensive instigation. In this context, resistance (RT) and power training (PT) have received considerable attention, and experts in the field have recently suggested that both training modalities may improve frailty-related parameters. However, most studies have only included robust people and investigated frailty as a secondary outcome, so that current literature only allows RT and PT preventive programs against frailty to be designed. Here, we provide evidence-based critical recommendations for the prescription of RT and PT programs against incident frailty in community-dwellers.

Inverse Association of Handgrip Strength With Risk of Heart Failure

OBJECTIVE

To evaluate the nature, magnitude, and specificity of the association between handgrip strength (HGS) and heart failure (HF) risk.

PATIENTS AND METHODS

Handgrip strength was assessed at baseline from March 1, 1998, to December 31, 2001, by use of a hand dynamometer in the Finnish Kuopio Ischemic Heart Disease prospective population-based cohort of 770 men and women aged 61 to 74 years without a history of HF. Relative HGS was obtained by dividing the absolute value by body weight. Hazard ratios (HRs) with 95% CIs were estimated with Cox regression models. We used multiple imputation to account for missing data.

RESULTS

During a median (interquartile range) follow-up of 17.1 (11.3-18.3) years, 177 HF events were recorded. Handgrip strength was continually associated with risk of HF, consistent with a curvilinear shape. On adjustment for several established risk factors and other potential confounders, the HR (95% CI) for HF was 0.73 (0.59-0.91) per 1 SD increase in relative HGS. Comparing the top vs bottom tertiles of relative HGS, the corresponding adjusted HR was 0.55 (0.38-0.81). The association remained similar across several clinical subgroups. Imputed results were broadly similar to the observed results.

CONCLUSION

Relative HGS is inversely and continually associated with the future risk of HF in the general population. Studies are warranted to evaluate whether HGS may be a useful prognostic tool for HF in the general population and to determine whether resistance exercise training may lower the risk of HF.

Mitochondria Homeostasis and Oxidant/Antioxidant Balance in Skeletal Muscle-Do Myokines Play a Role?

Mitochondria are the cellular powerhouses that generate adenosine triphosphate (ATP) to substantiate various biochemical activities. Instead of being a static intracellular structure, they are dynamic organelles that perform constant structural and functional remodeling in response to different metabolic stresses. In situations that require a high ATP supply, new mitochondria are assembled (mitochondrial biogenesis) or formed by fusing the existing mitochondria (mitochondrial fusion) to maximize the oxidative capacity. On the other hand, nutrient overload may produce detrimental metabolites such as reactive oxidative species (ROS) that wreck the organelle, leading to the split of damaged mitochondria (mitofission) for clearance (mitophagy). These vital processes are tightly regulated by a sophisticated quality control system involving energy sensing, intracellular membrane interaction, autophagy, and proteasomal degradation to optimize the number of healthy mitochondria. The effective mitochondrial surveillance is particularly important to skeletal muscle fitness because of its large tissue mass as well as its high metabolic activities for supporting the intensive myofiber contractility. Indeed, the failure of the mitochondrial quality control system in skeletal muscle is associated with diseases such as insulin resistance, aging, and muscle wasting. While the mitochondrial dynamics in cells are believed to be intrinsically controlled by the energy content and nutrient availability, other upstream regulators such as hormonal signals from distal organs or factors generated by the muscle itself may also play a critical role. It is now clear that skeletal muscle actively participates in systemic energy homeostasis via producing hundreds of myokines. Acting either as autocrine/paracrine or circulating hormones to crosstalk with other organs, these secretory myokines regulate a large number of physiological activities including insulin sensitivity, fuel utilization, cell differentiation, and appetite behavior. In this article, we will review the mechanism of myokines in mitochondrial quality control and ROS balance, and discuss their translational potential.

Frailty is not associated with hypertension, blood pressure or antihypertensive medication in community-dwelling older adults: A cross-sectional comparison across 3 frailty instruments

AIM

The present study investigated whether hypertension, blood pressure, and antihypertensive therapy were associated with frailty status in community-dwelling older adults. In addition, we tested whether such associations were consistent across different frailty instruments.

MATERIAL AND METHODS

Two-hundred older adults were enrolled in the study. Participant frailty status was determined according to a modified physical frailty phenotype (mFP), the FRAIL scale, and the Study of Osteoporotic Fracture (SOF) index. Blood pressure was assessed three times, in three different days, and mean values were used in the final analysis. Information pertaining to disease conditions and antihypertensive therapy were collected by two researchers through self-report and careful review of medical charts.

RESULTS

No significant differences in hemodynamic parameters, hypertension diagnosis, and antihypertensive therapy were observed across frailty statuses, regardless of the frailty assessment tool used.

CONCLUSION

Findings of the present study indicate that hypertension, blood pressure levels and antihypertensive medication were not cross-sectionally associated with frailty status in cognitively preserved community-dwelling older adults with low prevalence of comorbidities, regardless of the tool used for frailty identification.

Associations between Coenzyme Q10 Status, Oxidative Stress, and Muscle Strength and Endurance in Patients with Osteoarthritis

Osteoarthritis (OA) causes oxidative stress. Coenzyme Q10 is an antioxidant that participates in energy production in the human body. The purpose of this study was to investigate the relationships among coenzyme Q10 status, oxidative stress, antioxidant capacity, and muscle function in patients with OA. This case-control study recruited 100 patients with OA and 100 without OA. The coenzyme Q10 status, oxidative stress, antioxidant capacity, muscle mass (by dual-energy X-ray absorptiometry), muscle strength (hand-grip and leg-back strength), and muscle endurance (dumbbell curls, gait speed, chair-stand test, and short physical performance battery) were measured. The results showed that both OA and elderly subjects had a low coenzyme Q10 status (<0.5 μM). Oxidative stress was significantly negatively correlated with muscle function (protein carbonyl, p < 0.05). Coenzyme Q10 level was positively associated with antioxidant capacity, muscle mass, muscle strength and muscle endurance in patients with OA (p < 0.05). Since OA is an age-related disease, coenzyme Q10 may be consumed by oxidative stress and thereby affect muscle function. Raising coenzyme Q10 in patients with OA could be suggested, which may benefit their antioxidant capacity and muscle function.

Protein Intake and Frailty: A Matter of Quantity, Quality, and Timing

Frailty is a geriatric syndrome that refers to a state of reduced resiliency to stressful events that occurs in response to physiological and/or psychosocial detriments. Frailty is a predictor of poor prognosis, given that frail older adults are at higher risk of many adverse health-related events. Hence, the identification of potential strategies to prevent the development and progression of frailty is of extreme importance for avoiding its negative outcomes. An adequate protein consumption is advocated as a possible intervention for the management of frailty in older adults due to its effects on muscle mass and physical function. However, empirical evidence is still needed to support this proposition. On the other hand, substantial evidence from observational studies has provided important information on the association between frailty and dietary protein-related parameters. Here, we provide a narrative review of the current literature regarding the association between protein intake (amount (how much?), quality (what type?), and distribution across meals (when?)) and frailty-related parameters. The ultimate aim of this work is to offer practical, evidence-based indications to healthcare professionals responsible for the care of frail older adults.

Muscle-Organ Crosstalk: Focus on Immunometabolism

Skeletal muscle secretes several hundred myokines that facilitate communication from muscle to other organs, such as, adipose tissue, pancreas, liver, gut, and brain. The biological roles of myokines include effects on e.g., memory and learning, as well as glucose and lipid metabolism. The present minireview focuses on recent developments showing that exercise-induced myokines are involved in immunometabolism of importance for the control of e.g., tumor growth and chronic inflammation. In this review, immunometabolism is discussed as the non-immune related pathologies leading to an immune response and some degree of inflammation, which promotes metabolic abnormalities.

Muscle-Organ Crosstalk: The Emerging Roles of Myokines

Physical activity decreases the risk of a network of diseases, and exercise may be prescribed as medicine for lifestyle-related disorders such as type 2 diabetes, dementia, cardiovascular diseases, and cancer. During the past couple of decades, it has been apparent that skeletal muscle works as an endocrine organ, which can produce and secrete hundreds of myokines that exert their effects in either autocrine, paracrine, or endocrine manners. Recent advances show that skeletal muscle produces myokines in response to exercise, which allow for crosstalk between the muscle and other organs, including brain, adipose tissue, bone, liver, gut, pancreas, vascular bed, and skin, as well as communication within the muscle itself. Although only few myokines have been allocated to a specific function in humans, it has been identified that the biological roles of myokines include effects on, for example, cognition, lipid and glucose metabolism, browning of white fat, bone formation, endothelial cell function, hypertrophy, skin structure, and tumor growth. This suggests that myokines may be useful biomarkers for monitoring exercise prescription for people with, for example, cancer, diabetes, or neurodegenerative diseases.

Physical activity and exercise: Strategies to manage frailty

Frailty, a consequence of the interaction of the aging process and certain chronic diseases, compromises functional outcomes in the elderly and substantially increases their risk for developing disabilities and other adverse outcomes. Frailty follows from the combination of several impaired physiological mechanisms affecting multiple organs and systems. And, though frailty and sarcopenia are related, they are two different conditions. Thus, strategies to preserve or improve functional status should consider systemic function in addition to muscle conditioning. Physical activity/exercise is considered one of the main strategies to counteract frailty-related physical impairment in the elderly. Exercise reduces age-related oxidative damage and chronic inflammation, increases autophagy, and improves mitochondrial function, myokine profile, insulin-like growth factor-1 (IGF-1) signaling pathway, and insulin sensitivity. Exercise interventions target resistance (strength and power), aerobic, balance, and flexibility work. Each type improves different aspects of physical functioning, though they could be combined according to need and prescribed as a multicomponent intervention. Therefore, exercise intervention programs should be prescribed based on an individual's physical functioning and adapted to the ensuing response.

Myokines: a descriptive review

In the last years, scientists have shown that skeletal muscle is not a pure locomotor unit or responsible for propulsion and posture. Skeletal muscle encompasses one of the major organs of the body (constituting about 40% of the body mass in non-obese men). It regulates energy and metabolic processes and is now recognized as an organ capable of producing molecules with vital functions. These molecules are termed myokines, a new field of research in the health sciences, and represent an open field of discoveries and applications in several areas. The aim of this review was to show the role of some well-known myokines in the maintenance of homeostasis. Our search was performed in databases such as Medline/Pubmed, Embase and Scielo. Some relevant myokines are interleukin-6 (IL-6), IL-8, IL-15, irisin, myostatin, fibroblast growth factor 21 (FGF21), leukemia inhibitory factor (LIF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1). They are related to play a positive or negative role in muscle function and metabolism homeostasis. They are associated with the regulation of glucose and lipid metabolism, the deposition of fat in the adipose tissue, and the "browning" of the white adipose tissue. For these reasons, they can interfere with the prevention of obesity, diabetes, metabolic syndrome, and cardiovascular diseases. The discovery of the myokines has opened a new direction in understanding the effects of exercises on humans.

Physical Exercise and Myokines: Relationships with Sarcopenia and Cardiovascular Complications

Skeletal muscle is capable of secreting different factors in order to communicate with other tissues. These mediators, the myokines, show potentially far-reaching effects on non-muscle tissues and can provide a molecular interaction between muscle and body physiology. Sarcopenia is a chronic degenerative neuromuscular disease closely related to cardiomyopathy and chronic heart failure, which influences the production and release of myokines. Our objective was to explore the relationship between myokines, sarcopenia, and cardiovascular diseases (CVD). The autocrine, paracrine, and endocrine actions of myokines include regulation of energy expenditure, insulin sensitivity, lipolysis, free fatty acid oxidation, adipocyte browning, glycogenolysis, glycogenesis, and general metabolism. A sedentary lifestyle accelerates the aging process and is a risk factor for developing sarcopenia, metabolic syndrome, and CVD. Increased adipose tissue resulting from the decrease in muscle mass in patients with sarcopenia may also be involved in the pathology of CVD. Myokines are protagonists in the complex condition of sarcopenia, which is associated with adverse clinical outcomes in patients with CVD. The discovery of new pathways and the link between myokines and CVD remain a cornerstone toward multifaceted interventions and perhaps the minimization of the damage resulting from muscle loss induced by factors such as atherosclerosis.

Effects of Combined Resistance and Power Training on Cognitive Function in Older Women: A Randomized Controlled Trial

The present study compared the effects of traditional resistance training (TRT) and combined power training (PT) and TRT (PTRT) on cognitive parameters and serum brain-derived neurotrophic factor (BDNF) levels in non-demented, well-functioning, community-dwelling older women. Forty-five older women were randomized into one of three experimental groups: TRT, PTRT, and control group (CG). Cognitive tests explored global cognitive function, short-term memory, and dual-task performance. Serum BDNF levels were assessed at baseline and after the intervention. Exercise sessions were performed twice a week over 22 weeks. In TRT, exercise sessions were based on three sets of 8-10 repetitions at "difficult" intensity. In PTRT, the first session was based on PT (three sets of 8-10 repetitions at "moderate" intensity), while the second session was similar to the TRT. Our analyses indicated that overall cognitive function, short-term memory, and dual-task performance were similarly improved after TRT and PTRT. Serum BDNF concentrations were not altered by any training protocol. In conclusion, the two RT programs tested in the present trial improved global cognitive function, short-term memory and dual task performance in non-demented, well-functioning, community-dwelling older women. In addition, our findings suggest that mechanisms other than BDNF may be associated with such improvements.

Is inflammatory signaling involved in disease-related muscle wasting? Evidence from osteoarthritis, chronic obstructive pulmonary disease and type II diabetes

Muscle loss is an important feature that occurs in multiple pathologies including osteoarthritis (OA), chronic obstructive pulmonary disease (COPD) and type II diabetes (T2D). Despite differences in pathogenesis and disease-related complications, there are reasons to believe that some fundamental underlying mechanisms are inherent to the muscle wasting process, irrespective of the pathology. Recent evidence shows that inflammation, either local or systemic, contributes to the modulation of muscle mass and/or muscle strength, via an altered molecular profile in muscle tissue. However, it remains ambiguous to which extent and via which mechanisms inflammatory signaling affects muscle mass in disease. Therefore, the objective of the present review is to discuss the role of inflammation on skeletal muscle anabolism, catabolism and functionality in three pathologies that are characterized by an eventual loss in muscle mass (and muscle strength), i.e. OA, COPD and T2D. In OA and COPD, most rodent models confirmed that systemic (COPD) or muscle (OA) inflammation directly induces muscle loss or muscle dysfunctionality. However, in a patient population, the association between inflammation and muscular maladaptations are more ambiguous. For example, in T2D patients, systemic inflammation is associated with muscle loss whereas in OA patients this link has not consistently been established. T2D rodent models revealed that increased levels of advanced glycation end-products (AGEs) and a decreased mTORC1 activation play a key role in muscle atrophy, but it remains to be elucidated whether AGEs and mTORC1 are interconnected and contribute to muscle loss in T2D patients. Generally, if any, associations between inflammation and muscle are mainly based on observational and cross-sectional data. There is definitely a need for longitudinal evidence through well-powered randomized control trials that take into account confounders such as age, disease-phenotypes, comorbidities, physical (in) activity etc. This will allow to improve our understanding of the complex interaction between inflammatory signaling and muscle mass loss and hence contribute to the development of therapeutic strategies to combat muscle wasting in these diseases.

Handgrip strength is inversely associated with fatal cardiovascular and all-cause mortality events

Purpose: We aimed to assess the associations of handgrip strength (HS) with cardiovascular and all-cause mortality and whether adding data on HS to cardiovascular disease (CVD) risk factors is associated with improvement in CVD mortality prediction.Design: Handgrip strength was assessed in a population-based sample of 861 participants aged 61-74 years at baseline. Relative HS was obtained by dividing the absolute value by body weight.Results: During a median (interquartile range) follow-up of 17.3 (12.6-18.4) years, 116 fatal coronary heart diseases (CHDs), 195 fatal CVDs and 412 all-cause mortality events occurred. On adjustment for several risk factors, the hazard ratios (95% confidence intervals (CIs)) for fatal CHD, fatal CVD and all-cause mortality were 0.59 (0.37-0.95), 0.59 (0.41-0.86) and 0.66 (0.51-0.84), respectively, comparing extreme tertiles of relative HS. Adding relative HS to a CVD mortality risk prediction model containing established risk factors did not improve discrimination or reclassification using Harrell's C-index (C-index change: 0.0034; p = .65), integrated-discrimination-improvement (0.0059; p = .20) and net-reclassification-improvement (-1.31%; p = .74); however, there was a significant difference in -2 log likelihood (p < .001).Conclusions: Relative HS is inversely associated with CHD, CVD and all-cause mortality events. Adding relative HS to conventional risk factors improves CVD risk assessment using sensitive measures of discrimination.KEY MESSAGESHandgrip strength (HS) assessment is simple, inexpensive and it takes only a few minutes to measure in clinical practice; however, its prognostic role for fatal cardiovascular outcomes on top of traditional risk factors in apparently healthy populations is uncertain.In a population-based prospective cohort study, good HS adjusted for body weight was associated with lower risk of fatal cardiovascular outcomes and the associations remained consistent across several clinically relevant subgroups.Handgrip strength may be a useful prognostic tool for fatal CHD and CVD events, in the general population.

A focused review of myokines as a potential contributor to muscle hypertrophy from resistance-based exercise

PURPOSE

Resistance exercise induces muscle growth and is an important treatment for age-related losses in muscle mass and strength. Myokines are hypothesized as a signal conveying physiological information to skeletal muscle, possibly to "fine-tune" other regulatory pathways. While myokines are released from skeletal muscle following contraction, their role in increasing muscle mass and strength in response to resistance exercise or training is not established. Recent research identified both local and systemic release of myokines after an acute bout of resistance exercise. However, it is not known whether myokines with putative anabolic function are mechanistically involved in producing muscle hypertrophy after resistance exercise. Further, nitric oxide (NO), an important mediator of muscle stem cell activation, upregulates the expression of certain myokine genes in skeletal muscle.

METHOD

In the systemic context of complex hypertrophic signaling, this review: (1) summarizes literature on several well-recognized, representative myokines with anabolic potential; (2) explores the potential mechanistic role of myokines in skeletal muscle hypertrophy; and (3) identifies future research required to advance our understanding of myokine anabolism specifically in skeletal muscle.

RESULT

This review establishes a link between myokines and NO production, and emphasizes the importance of considering systemic release of potential anabolic myokines during resistance exercise as complementary to other signals that promote hypertrophy.

CONCLUSION

Investigating adaptations to resistance exercise in aging opens a novel avenue of interdisciplinary research into myokines and NO metabolites during resistance exercise, with the longer-term goal to improve muscle health in daily living, aging, and rehabilitation.

Protein-Related Dietary Parameters and Frailty Status in Older Community-Dwellers across Different Frailty Instruments

The present study investigated the associations between frailty status and (a) daily protein intake, (b) daily body weight-adjusted protein intake, (c) branched-chain amino acid (BCAA) consumption, (d) evenness of protein distribution across main meals, (e) number of daily meals providing at least 30 g of protein, and (f) number of daily meals providing at least 0.4 g protein/kg of body weight in community-dwelling older adults. The relationship between frailty status and protein-related dietary parameters was explored across different frailty assessment tools. Two hundred older adults were enrolled in the study. Participant frailty status was determined according to a modified Fried’s frailty phenotype (mFP), the FRAIL scale, and the Study of Osteoporotic Fracture (SOF) index. Diet was assessed by 24-h dietary recall, while diet composition was estimated using a nutritional software. A frailty instrument-dependent relationship was observed between frailty status and protein-related dietary parameters. Protein consumption was associated with frailty status only in participants identified as frail according to the mFP. In addition, protein and BCAA intake was found to be greater in robust and pre-frail participants relative to their frail counterparts. Our findings suggest that the association between frailty and protein-related dietary parameters is tool dependent. Specifically, protein and BCAA consumption appears to be lower only in older adults identified as frail by the mFP.

Targeting Age-Dependent Functional and Metabolic Decline of Human Skeletal Muscle: The Geroprotective Role of Exercise, Myokine IL-6, and Vitamin D

In the elderly, whole-body health largely relies on healthy skeletal muscle, which controls body stability, locomotion, and metabolic homeostasis. Age-related skeletal muscle structural/functional deterioration is associated with a higher risk of severe comorbid conditions and poorer outcomes, demanding major socioeconomic costs. Thus, the need for efficient so-called geroprotective strategies to improve resilience and ensure a good quality of life in older subjects is urgent. Skeletal muscle senescence and metabolic dysregulation share common cellular/intracellular mechanisms, potentially representing targets for intervention to preserve muscle integrity. Many factors converge in aging, and multifaceted approaches have been proposed as interventions, although they have often been inconclusive. Physical exercise can counteract aging and metabolic deficits, not only in maintaining tissue mass, but also by preserving tissue secretory function. Indeed, skeletal muscle is currently considered a proper secretory organ controlling distant organ functions through immunoactive regulatory small peptides called myokines. This review provides a current perspective on the main biomolecular mechanisms underlying age-dependent and metabolic deterioration of skeletal muscle, herein discussed as a secretory organ, the functional integrity of which largely depends on exercise and myokine release. In particular, muscle-derived interleukin (IL)-6 is discussed as a nutrient-level biosensor. Overall, exercise and vitamin D are addressed as optimal geroprotective strategies in view of their multi-target effects.

Myokines as biomarkers of frailty and cardiovascular disease risk in females

Frailty is a risk factor for cardiovascular disease (CVD). Biomarkers have the potential to detect the early stages of frailty, such as pre-frailty. Myokines may act as biomarkers of frailty-related disease progression, as a decline in muscle health is a hallmark of the frailty phenotype. This study is a secondary analysis of 104 females 55 years of age or older with no previous history of CVD. Differences in systemic myokine concentrations based on frailty status and CVD risk profile were examined using a case-control design. Propensity matching identified two sets of 26 pairs with pre-frailty as the exposure variable in low or elevated CVD risk groups for a total 104 female participants. Frailty was assessed using the Fried Criteria (FC) and CVD risk was assessed using the Framingham Risk Score (FRS). Factorial ANOVA compared the main effects of frailty, CVD risk, and their interaction on the concentrations of 15 myokines. Differences were found when comparing elevated CVD risk status with low for the concentrations of EPO (384.76 ± 1046.07 vs. 206.63 ± 284.61 pg/mL, p = .001), FABP3 (2772.61 ± 3297.86 vs. 1693.31 ± 1019.34 pg/mL, p = .017), FGF21 (193.17 ± 521.09 vs. 70.18 ± 139.51 pg/mL, p = .010), IL-6 (1.73 ± 4.97 vs. 0.52 ± 0.89 pg/mL, p = .023), and IL-15 (2.62 ± 10.56 vs. 0.92 ± 1.25 pg/mL, p = .022). Pre-frail females had lower concentrations of fractalkine compared to robust (27.04 ± 20.60 vs. 103.62 ± 315.45 pg/mL, p = .004). Interaction effects between frailty status and CVD risk for FGF21 and OSM were identified. In elevated CVD risk, pre-frail females, concentrations of FGF21 and OSM were lower than that of elevated CVD risk, robust females (69.10 ± 62.86 vs. 317.24 ± 719.69, p = .011; 1.73 ± 2.32 vs. 24.43 ± 69.21, p = .018, respectively). These data identified specific biomarkers of CVD risk and biomarkers of frailty that are exacerbated with CVD risk.