Sarcopenia--The search for emerging biomarkers

Long-term effects of the chronic administration of doxorubicin on aged skeletal muscle: An exploratory study in mice

The widely used chemotherapeutic drug doxorubicin (DOX) has been associated with adverse effects on the skeletal muscle, which can persist for years after the end of the treatment. These adverse effects may be exacerbated in older patients, whose skeletal muscle might already be impaired by aging. Nonetheless, the mediators responsible for DOX-induced myotoxicity are still largely unidentified, particularly the ones involved in the long-term effects that negatively affect the quality of life of the patients. Therefore, this study aimed to investigate the long-term effects of the chronic administration of DOX on the soleus muscle of aged mice. For that and to mimic the clinical regimen, a dose of 1.5 mg kg-1 of DOX was administered two times per week for three consecutive weeks in a cumulative dose of 9 mg kg-1 to 19-month-old male mice, which were sacrificed two months after the last administration. Body wasting and the atrophy of the soleus muscle, as measured by a decrease in the cross-sectional area of the soleus muscle fibers, were identified as long-term effects of DOX administration. The atrophy observed was correlated with increased reactive oxygen species production and caspase-3 activity. An impaired skeletal muscle regeneration was also suggested due to the correlation between satellite cells activation and the soleus muscle fibers atrophy. Systemic inflammation, skeletal muscle energy metabolism and neuromuscular junction-related markers do not appear to be involved in the long-term DOX-induced skeletal muscle atrophy. The data provided by this study shed light on the mediators involved in the overlooked long-term DOX-induced myotoxicity, paving the way to the improvement of the quality of life and survival rates of older cancer patients.

Adipose tissue in older individuals: a contributing factor to sarcopenia

Sarcopenia is a geriatric syndrome characterized by a functional decline in muscle. The prevalence of sarcopenia increases with natural aging, becoming a serious health problem among elderly individuals. Therefore, understanding the pathology of sarcopenia is critical for inhibiting age-related alterations and promoting health and longevity in elderly individuals. The development of sarcopenia may be influenced by interactions between visceral and subcutaneous adipose tissue and skeletal muscle, particularly under conditions of chronic low-grade inflammation and metabolic dysfunction. This hypothesis is supported by the following observations: (i) accumulation of senescent cells in both adipose tissue and skeletal muscle with age; (ii) gut dysbiosis, characterized by an imbalance in gut microbial communities as the main trigger for inflammation, sarcopenia, and aged adipose tissue; and (iii) microbial dysbiosis, which could impact the onset or progression of a senescent state. Moreover, adipose tissue acts as an endocrine organ, releasing molecules that participate in intricate communication networks between organs. Our discussion focuses on novel adipokines and their role in regulating adipose tissue and muscle, particularly those influenced by aging and obesity, emphasizing their contributions to disease development. On the basis of these findings, we propose that age-related adipose tissue and sarcopenia are disorders characterized by chronic inflammation and metabolic dysregulation. Finally, we explore new potential therapeutic strategies involving specialized proresolving mediator (SPM) G protein-coupled receptor (GPCR) agonists, non-SPM GPCR agonists, transient receptor potential (TRP) channels, antidiabetic drugs in conjunction with probiotics and prebiotics, and compounds designed to target senescent cells and mitigate their pro-inflammatory activity.

Mass Spectrometry-Based Multiomics Identifies Metabolic Signatures of Sarcopenia in Rhesus Monkey Skeletal Muscle

Sarcopenia is a progressive disorder characterized by age-related loss of skeletal muscle mass and function. Although significant progress has been made over the years to identify the molecular determinants of sarcopenia, the precise mechanisms underlying the age-related loss of contractile function remains unclear. Advances in "omics" technologies, including mass spectrometry-based proteomic and metabolomic analyses, offer great opportunities to better understand sarcopenia. Herein, we performed mass spectrometry-based analyses of the vastus lateralis from young, middle-aged, and older rhesus monkeys to identify molecular signatures of sarcopenia. In our proteomic analysis, we identified proteins that change with age, including those involved in adenosine triphosphate and adenosine monophosphate metabolism as well as fatty acid beta oxidation. In our untargeted metabolomic analysis, we identified metabolites that changed with age largely related to energy metabolism including fatty acid beta oxidation. Pathway analysis of age-responsive proteins and metabolites revealed changes in muscle structure and contraction as well as lipid, carbohydrate, and purine metabolism. Together, this study discovers new metabolic signatures and offers new insights into the molecular mechanisms underlying sarcopenia for the evaluation and monitoring of a therapeutic treatment of sarcopenia.

Extracellular vesicles in cancer cachexia: deciphering pathogenic roles and exploring therapeutic horizons

Cancer cachexia (CC) is a debilitating syndrome that affects 50-80% of cancer patients, varying in incidence by cancer type and significantly diminishing their quality of life. This multifactorial syndrome is characterized by muscle and fat loss, systemic inflammation, and metabolic imbalance. Extracellular vesicles (EVs), including exosomes and microvesicles, play a crucial role in the progression of CC. These vesicles, produced by cancer cells and others within the tumor environment, facilitate intercellular communication by transferring proteins, lipids, and nucleic acids. A comprehensive review of the literature from databases such as PubMed, Scopus, and Web of Science reveals insights into the formation, release, and uptake of EVs in CC, underscoring their potential as diagnostic and prognostic biomarkers. The review also explores therapeutic strategies targeting EVs, which include modifying their release and content, utilizing them for drug delivery, genetically altering their contents, and inhibiting key cachexia pathways. Understanding the role of EVs in CC opens new avenues for diagnostic and therapeutic approaches, potentially mitigating the syndrome's impact on patient survival and quality of life.

Restoration of epigenetic impairment in the skeletal muscle and chronic inflammation resolution as a therapeutic approach in sarcopenia

Sarcopenia is an age-associated loss of skeletal muscle mass, strength, and function, accompanied by severe adverse health outcomes, such as falls and fractures, functional decline, high health costs, and mortality. Hence, its prevention and treatment have become increasingly urgent. However, despite the wide prevalence and extensive research on sarcopenia, no FDA-approved disease-modifying drugs exist. This is probably due to a poor understanding of the mechanisms underlying its pathophysiology. Recent evidence demonstrate that sarcopenia development is characterized by two key elements: (i) epigenetic dysregulation of multiple molecular pathways associated with sarcopenia pathogenesis, such as protein remodeling, insulin resistance, mitochondria impairments, and (ii) the creation of a systemic, chronic, low-grade inflammation (SCLGI). In this review, we focus on the epigenetic regulators that have been implicated in skeletal muscle deterioration, their individual roles, and possible crosstalk. We also discuss epidrugs, which are the pharmaceuticals with the potential to restore the epigenetic mechanisms deregulated in sarcopenia. In addition, we discuss the mechanisms underlying failed SCLGI resolution in sarcopenia and the potential application of pro-resolving molecules, comprising specialized pro-resolving mediators (SPMs) and their stable mimetics and receptor agonists. These compounds, as well as epidrugs, reveal beneficial effects in preclinical studies related to sarcopenia. Based on these encouraging observations, we propose the combination of epidrugs with SCLI-resolving agents as a new therapeutic approach for sarcopenia that can effectively attenuate of its manifestations.

[Association of grip strength and knee extensors with nutritional status of community-dwelling older adults]

AIM

To determine the association of hand grip strength and knee extensor strength with the nutritional status of community-dwelling older adults.

MATERIAL AND METHODS

Observational cross-sectional study. Weight and height of 847 older adults were analyzed according to body mass index and classified into four nutritional categories according to the Chilean Ministry of Health. Hand grip and knee extensors strength for both extremities were evaluated. Strength was normalized by body mass. Spearman's correlation between body mass index and muscle strength was used.

RESULTS

The sample was 582 women, 265 men and an average age of 71.72±7.09. The women had a BMI of 30.03±5.48 and the men of 27.64 ± 4.05, the most numerous category was normal weight (n = 288) and the lowest low weight (n = 74). Hand grip strength presented a higher correlation than knee extensors, specifically, right hand grip strength (r: -0.40). The highest correlation and significance were presented by the obese category for all strength measurements, with right hand grip strength being the highest (r: -0.29).

CONCLUSIONS

The increase in the nutritional status of older adults has a negative influence on muscle strength. The best association between body mass index and muscle strength was the right hand grip. The finding of the increase in life expectancy as the nutritional status of the sample decreases stands out. Future studies are needed to generate percentiles and normalized values in the Chilean population.

Combined Plasma DHA-Containing Phosphatidylcholine PCaa C38:6 and Tetradecanoyl-Carnitine as an Early Biomarker for Assessing the Mortality Risk among Sarcopenic Patients

The coming of the hyper-aged society in Taiwan prompts us to investigate the relationship between the metabolic status of sarcopenic patients and their most adverse outcome-death. We studied the association between any plasma metabolites and the risk for mortality among older Taiwanese sarcopenic patients. We applied a targeted metabolomic approach to study the plasma metabolites of adults aged ≥65 years, and identified the metabolic signature predictive of the mortality of sarcopenic patients who died within a 5.5-year follow-up period. Thirty-five sarcopenic patients who died within the follow-up period (Dead cohort) had shown a specific plasma metabolic signature, as compared with 54 patients who were alive (Alive cohort). Only 10 of 116 non-sarcopenic individuals died during the same period. After multivariable adjustment, we found that sex, hypertension, tetradecanoyl-carnitine (C14-carnitine), and docosahexaenoic acid (DHA)-containing phosphatidylcholine diacyl (PCaa) C38:6 and C40:6 were important risk factors for the mortality of sarcopenic patients. Low PCaa C38:6 levels and high C14-carnitine levels correlated with an increased mortality risk; this was even the same for those patients with hypertension (HTN). Our findings suggest that plasma PCaa C38:6 and acylcarnitine C14-carnitine, when combined, can be a better early biomarker for evaluating the mortality risk of sarcopenia patients.

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

Changes and correlation analysis of intestinal microflora composition, inflammatory index, and skeletal muscle mass in elderly patients with sarcopenia

AIM

This study aimed to explore the alterations in characteristics of intestinal flora, inflammatory factors and skeletal muscle mass in elderly patients affected by sarcopenia, as well as the correlation among the three, in order to provide a reference for the early identification, intervention, and treatment of sarcopenia in elderly patients.

METHOD

A total of 206 elderly patients (≥60 years old) admitted to the Geriatric Outpatient Department of China Resources Wugang General Hospital were included in this study as the research participants. The differences in the general data, laboratory examination and intestinal flora in patients between the two groups were statistically analyzed, and the correlation between intestinal flora composition and skeletal muscle mass index, grip and inflammatory factors was also determined.

RESULTS

The normal group and sarcopenia group exhibited a significant difference in the composition of the intestinal flora (P < 0.05). The abundance of Escherichia-Shigella between the two groups was negatively correlated with the patient's relative skeletal muscle mass index and positively correlated with the interleukin-6 (IL-6) level; moreover, Lacchnospira abundance was positively correlated with relative skeletal muscle mass index; Lactobacillus and Roseburia abundance were negatively correlated with IL-6; and Lactobacillus, Lachnospira, and Eubacterium_rectale_group were positively correlated with grip, and the differences were statistically significant (P < 0.05).

CONCLUSION

Overall, it was found that elderly patients with sarcopenia have intestinal flora disorders, and the abundance of such flora was negatively correlated with the relative skeletal muscle mass index, which was positively correlated with the IL-6 level. Geriatr Gerontol Int 2024; 24: 140-146.

What Does Sarcopenia Have to Do with Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease. As the second stage of developing steatosis, nonalcoholic hepatitis (NASH) carries the risk of fibrosis, cirrhosis, and hepatocellular carcinoma. Sarcopenia is defined as a condition characterized by a decrease in muscle mass and functional decline. Both NAFLD and sarcopenia are global problems. The pathophysiological mechanisms that link the two entities of the disease are insulin resistance, inflammation, nutritional deficiencies, impairment of myostatin and adiponectin, or physical inactivity. Furthermore, disorders of the gut-liver axis appear to induce the process of developing NAFLD and sarcopenia. The correlations between NAFLD and sarcopenia appear to be bidirectional, so the main objective of the review was to determine the cause-and-effect relationship between the two diseases.

Validated Tools for Screening Sarcopenia: A Scoping Review

OBJECTIVE

Choosing the optimal sarcopenia screening tool for a specific clinical scenario is challenging. We aimed to summarize all validated sarcopenia screening tools with diagnostic accuracy tested in one or more study populations.

DESIGN

Scoping review.

SETTING AND PARTICIPANTS

Hospitals, nursing homes, communities, or health checkups.

METHODS

We systematically searched 3 databases in April 2022: MEDLINE, EMBASE, and CENTRAL. Two review authors independently performed the study selection and data extraction. The included tools' contents, characteristics, and number of citations were summarized and visualized.

RESULTS

We summarized 102 diagnostic accuracy studies involving 53 screening tools, classified into 7 groups: questionnaires (n = 13); serum biomarkers (n = 10); formulas, algorithms, and models (n = 9); physical ability tests (n = 9); integration tools (n = 7); anthropometric indices (n = 3); and ultrasound or bioimpedance analysis (n = 2). The most commonly used questionnaire was SARC-F (770 citations), followed by SARC-CalF (254 citations) and MSRA-7 (61 citations). Handgrip strength and Ishii score were the most widely used physical performance tests (331 citations) and formulas (294 citations), respectively. Sarcopenia index (based on serum cystatin C and creatinine) and calf circumference were the most commonly used serum biomarkers (123 citations) and anthropometric indexes (127 citations), respectively. Ultrasound was the most commonly used imaging tool for screening sarcopenia (57 citations). The included tools varied significantly in content. Various tools assessed some or all components of sarcopenia with different methods, and others assessed different domains, such as age, body mass index, falls, diet, and even mental health. We also summarized the screening tools that were validated in different clinical settings (hospitals, communities, nursing homes, and health checkups).

CONCLUSIONS AND IMPLICATIONS

More than 50 validated tools are currently available for screening sarcopenia in different clinical settings. The results of this review may help clinicians and researchers in selecting optimal tools for sarcopenia in different clinical scenarios and in developing future tools.

Neurofilament-light chains (NF-L), a biomarker of neuronal damage, is increased in patients with severe sarcopenia: results of the SarcoPhAge study

BACKGROUND

As clinical tests, such as gait speed, require nervous system integrity to be performed properly, sarcopenia shares features with neurological diseases. Neurofilament light chains (NF-L) are now used as a blood-biomarker of neuronal damage, and its expression might be altered in sarcopenia. We aimed to assess NF-L concentrations in a large cohort of older individuals screened for sarcopenia.

METHODS

The SarcoPhAge cohort is a Belgian cohort of 534 community-dwelling older adults with an ongoing 10-year follow-up. Sarcopenia diagnosis was established at inclusion according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Muscle strength was evaluated with a hydraulic hand dynamometer, appendicular lean mass by Dual-Energy X-ray Absorptiometry (DXA) and physical performance by the Short Physical Performance Battery (SPPB). NF-L was measured on all available sera collected at the time of inclusion (n = 409) using SiMoA technology (Quanterix°).

RESULTS

In the multivariate model, NF-L was associated with performance tests such as gait speed (p < 0.0001) and SPPB scores (p = 0.0004). An association was also observed with muscle strength (p = 0.0123) and lean mass (p = 0.0279). In the logistic regression model, NF-L was an independent predictor of severe sarcopenia (p = 0.0338; OR = 20.0; 95% CI 1.39-287.7) with satisfactory diagnostic accuracy (AUC: 0.828) and subjects with an SPPB score ≤ 8 had higher odds of having increased NF-L (p < 0.0001; OR = 23.9; 95% CI 5.5-104).

CONCLUSIONS

These data highlight the potential for using NF-L to investigate the pathophysiology of sarcopenia severity and the neurological features associated with performance tests. However, these results need to be confirmed with other cohorts in different settings.

Weight bearing training alleviates muscle atrophy and pyroptosis of middle-aged rats

Background

Age-related muscle atrophy and adipose accumulation begin to occur in young and middle-aged individuals, and exercise at an early age improves body composition. Pyroptosis may play an essential role in age-related low-grade inflammation. This study aimed to explore the alleviation of muscle atrophy by weight-bearing training with increasing age via inhibition of pyroptosis.

Methods

Ninety 8-month-old male SD rats were randomly divided into three groups: (1) normal baseline group (N group, n = 10), sacrificed after adaptive feeding; control group (C group, n = 40); and weight-bearing running group (R group, n = 40). Blood samples, adipose tissue (AT), and extensor digitorum longus (EDL) were collected after 8, 16, 24, and 32-weeks intervention.

Results

The body weight, muscle mass, fat mass, plasma lipid, AT wet weight, adipocyte cross-sectional area (CSA), and apoptosis rates of AT and EDL were increased, while the muscle mass, wet weight, and fiber CSA of EDL were decreased by aging, which were reversed by exercise. Weight-bearing training promoted protein synthesis in EDL, inhibited protein degradation in EDL, and expression of pyroptotic key proteins in EDL and AT in rats.

Conclusion

Weight-bearing training improves body composition and alleviates age-related muscle atrophy in rats, and its mechanism may be related to the inhibition of pyroptosis in the EDL and AT and the improvement of muscle protein metabolism.

Inflammatory biomarkers at different stages of Sarcopenia in older women

In recent years, studies have found that Sarcopenia alters inflammatory biomarkers. However, the behavior of inflammatory biomarkers at different stages of Sarcopenia is not well understood. This study aimed to compare a broad panel of inflammatory biomarkers in older women at different stages of Sarcopenia. The study included 71 Brazilian community-dwelling older women. Muscle Strength was assessed by using handgrip strength (Jamar dynamometer). The Short Physical Performance Battery (SPPB) was performed to assess the physical performance, and body composition was assessed by DEXA. Sarcopenia was diagnosed and classified according to the EWGSOP2 criteria. Blood was drawn, and inflammatory biomarkers associated with Sarcopenia (IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, TNF, adiponectin, leptin, resistin, BDNF, sTNFr-1 and sTNFr-2) was analysed. After diagnosis and classification of sarcopenia, 45% of women did not present Sarcopenia (NS, N = 32), 23.9% were diagnosed with Sarcopenia Probable (SP, N = 17), 19,7% with Sarcopenia Confirmed (SC, N = 14), and 11.3% with Severe Sarcopenia (SS, N = 8). The analysis of inflammatory biomarkers revealed that the more advanced the stage of Sarcopenia, the higher the levels of BDNF, IL-8, sTNFr-1, and sTNFr-2. The assessment of BDNF, IL-8, sTNFr-1, and sTNFr-2 levels may be an adjuvant tool in diagnosis and severity classification of Sarcopenia in older Brazilian women.

Brain-derived neurotrophic factor: Its role in energy balance and cancer cachexia

Brain-derived neurotrophic factor (BDNF) plays an important role in the development of the central and peripheral nervous system during embryogenesis. In the mature central nervous system, BDNF is required for the maintenance and enhancement of synaptic transmissions and the survival of neurons. Particularly, it is involved in the modulation of neurocircuits that control energy balance through food intake, energy expenditure, and locomotion. Regulation of BDNF in the central nervous system is complex and environmental factors affect its expression in murine models which may reflect to phenotype dramatically. Furthermore, BDNF and its high-affinity receptor tropomyosin receptor kinase B (TrkB), as well as pan-neurotrophin receptor (p75NTR) is expressed in peripheral tissues in adulthood and their signaling is associated with regulation of energy balance. BDNF/TrkB signaling is exploited by cancer cells as well and BDNF expression is increased in tumors. Intriguingly, previously demonstrated roles of BDNF in regulation of food intake, adipose tissue and muscle overlap with derangements observed in cancer cachexia. However, data about the involvement of BDNF in cachectic cancer patients and murine models are scarce and inconclusive. In the future, knock-in and/or knock-out experiments with murine cancer models could be helpful to explore potential new roles for BDNF in the development of cancer cachexia.

C-terminal agrin fragment as a biomarker of muscle wasting and weakness: a narrative review

Ageing is accompanied by an inexorable loss of muscle mass and functionality and represents a major risk factor for numerous diseases such as cancer, diabetes and cardiovascular and pulmonary diseases. This progressive loss of muscle mass and function may also result in the insurgence of a clinical syndrome termed sarcopenia, exacerbated by inactivity and disease. Sarcopenia and muscle weakness yield the risk of falls and injuries, heavily impacting on health and social costs. Thus, screening, monitoring and prevention of conditions inducing muscle wasting and weakness are essential to improve life quality in the ageing modern society. To this aim, the reliability of easily accessible and non-invasive blood-derived biomarkers is being evaluated. C-terminal agrin fragment (CAF) has been widely investigated as a neuromuscular junction (NMJ)-related biomarker of muscle dysfunction. This narrative review summarizes and critically discusses, for the first time, the studies measuring CAF concentration in young and older, healthy and diseased individuals, cross-sectionally and in response to inactivity and physical exercise, providing possible explanations behind the discrepancies observed in the literature. To identify the studies investigating CAF in the above-mentioned conditions, all the publications found in PubMed, written in English and measuring this biomarker in blood from 2013 (when CAF was firstly measured in human serum) to 2022 were included in this review. CAF increases with age and in sarcopenic individuals when compared with age-matched, non-sarcopenic peers. In addition, CAF was found to be higher than controls in other muscle wasting conditions, such as diabetes, COPD, chronic heart failure and stroke, and in pancreatic and colorectal cancer cachectic patients. As agrin is also expressed in kidney glomeruli, chronic kidney disease and transplantation were shown to have a profound impact on CAF independently from muscle wasting. CAF concentration raises following inactivity and seems to be lowered or maintained by exercise training. Finally, CAF was reported to be cross-sectionally correlated to appendicular lean mass, handgrip and gait speed; whether longitudinal changes in CAF are associated with those in muscle mass or performance following physical exercise is still controversial. CAF seems a reliable marker to assess muscle wasting in ageing and disease, also correlating with measurements of appendicular lean mass and muscle function. Future research should aim at enlarging sample size and accurately reporting the medical history of each patient, to normalize for any condition, including chronic kidney disease, that may influence the circulating concentration of this biomarker.

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Effect of targeted intervention on C-terminal agrin fragment and its association with the components of sarcopenia: a scoping review

BACKGROUND

C-terminal Agrin Fragment (CAF) has emerged as a potent biomarker for identifying sarcopenia. However, the effect of interventions on CAF concentration and the association of CAF with sarcopenia components are unclear.

OBJECTIVE

To review the association between CAF concentration and muscle mass, muscle strength, and physical performance among individuals with primary and secondary sarcopenia and to synthesize the effect of interventions on the change in the level of CAF concentration.

METHODS

A systematic literature search was conducted in six electronic databases, and studies were included if they met the selection criteria decided a priori. The data extraction sheet was prepared, validated, and extracted relevant data.

RESULTS

A total of 5,158 records were found, of which 16 were included. Among studies conducted on individuals with primary sarcopenia, muscle mass was significantly associated with CAF levels, followed by hand grip strength (HGS) and physical performance, with more consistent findings in males. While in secondary sarcopenics, the strongest association was found for HGS and CAF levels, followed by physical performance and muscle mass. CAF concentration was reduced in trials that used functional, dual task, and power training, whereas resistance training and physical activity raised CAF levels. Hormonal therapy did not affect serum CAF concentration.

CONCLUSION(S)

The association between CAF and sarcopenic assessment parameters varies in primary and secondary sarcopenics. The findings would help practitioners and researchers choose the best training mode/parameters/exercises to reduce CAF levels and, eventually, manage sarcopenia.

Chinese expert consensus on prevention and control interventions for older adults with physical functional impairment (2022)

Older adults are at high risk for functional impairment, which is closely related to sarcopenia, falls, and frailty. This seriously affects their quality of life and health, and places a heavy burden on society and families. Although domestic and foreign sports recommendations and prevention and control guidelines/expert consensus have been issued for healthy older adults and functional impairment-related diseases, there is no guidance on prevention and control interventions for older adults with physical functional impairment. In China, there is insufficient understanding of the importance of prevention and control interventions for functional impairment in older adults, and there are many drawbacks, such as unstandardized diagnosis and treatment, and relatively simple intervention methods. Therefore, the consensus expert group formulated a consensus based on domestic and foreign guidelines related to functional impairment in older adults to provide guidance for Chinese medical professionals working in the field of geriatrics.

Biochemical Markers of Musculoskeletal Health and Aging to be Assessed in Clinical Trials of Drugs Aiming at the Treatment of Sarcopenia: Consensus Paper from an Expert Group Meeting Organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the Centre Académique de Recherche et d'Expérimentation en Santé (CARES SPRL), Under the Auspices of the World Health Organization Collaborating Center for the Epidemiology of Musculoskeletal Conditions and Aging

In clinical trials, biochemical markers provide useful information on the drug's mode of action, therapeutic response and side effect monitoring and can act as surrogate endpoints. In pharmacological intervention development for sarcopenia management, there is an urgent need to identify biomarkers to measure in clinical trials and that could be used in the future in clinical practice. The objective of the current consensus paper is to provide a clear list of biochemical markers of musculoskeletal health and aging that can be recommended to be measured in Phase II and Phase III clinical trials evaluating new chemical entities for sarcopenia treatment. A working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) proposed classifying biochemical markers into 2 series: biochemical markers evaluating musculoskeletal status and biochemical markers evaluating causal factors. For series 1, the group agreed on 4 biochemical markers that should be assessed in Phase II or Phase III trials (i.e., Myostatin-Follistatin, Brain Derived Neurotrophic Factor, N-terminal Type III Procollagen and Serum Creatinine to Serum Cystatin C Ratio - or the Sarcopenia Index). For series 2, the group agreed on 6 biochemical markers that should be assessed in Phase II trials (i.e., the hormones insulin-like growth factor-1 (IGF-I), dehydroepiandrosterone sulphate, and cortisol, and the inflammatory markers C-reactive protein (CRP), interleukin-6 and tumor necrosis factor-α), and 2 in Phase III trials (i.e., IGF-I and CRP). The group also proposed optional biochemical markers that may provide insights into the mode of action of pharmacological therapies. Further research and development of new methods for biochemical marker assays may lead to the evolution of these recommendations.

Effects of a 2-year exercise training on neuromuscular system health in older individuals with low muscle function

BACKGROUND

Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, potentially determining the insurgence of sarcopenia. Evidence suggests that motoneuron and neuromuscular junction (NMJ) degeneration contribute to sarcopenia pathogenesis. Seeking for strategies able to slow down sarcopenia insurgence and progression, we investigated whether a 2-year mixed-model training involving aerobic, strength and balance exercises would be effective for improving or preserving motoneuronal health and NMJ stability, together with muscle mass, strength and functionality in an old, sarcopenic population.

METHODS

Forty-five sarcopenic elderly (34 females; 11 males) with low dual-energy X-ray absorptiometry (DXA) lean mass and Short Physical Performance Battery (SPPB) score <9 were randomly assigned to either a control group [Healthy Aging Lifestyle Education (HALE), n = 21] or an intervention group [MultiComponent Intervention (MCI), n = 24]. MCI trained three times per week for 2 years with a mix of aerobic, strength and balance exercises matched with nutritional advice. Before and after the intervention, ultrasound scans of the vastus lateralis (VL), SPPB and a blood sample were obtained. VL architecture [pennation angle (PA) and fascicle length (Lf)] and cross-sectional area (CSA) were measured. As biomarkers of neuronal health and NMJ stability status, neurofilament light chain (NfL) and C-terminal agrin fragment (CAF) concentrations were measured in serum. Differences in ultrasound parameters, NfL and CAF concentration and physical performance between baseline and follow-up were tested with mixed ANOVA or Wilcoxon test. The relationship between changes in physical performance and NfL or CAF concentration was assessed through correlation analyses.

RESULTS

At follow-up, MCI showed preserved VL architecture (PA, Lf) despite a reduced CSA (-8.4%, P < 0.001), accompanied by maintained CAF concentration and ameliorated overall SPPB performance (P = 0.007). Conversely, HALE showed 12.7% decrease in muscle CSA (P < 0.001), together with 5.1% and 5.5% reduction in PA and Lf (P < 0.001 and P = 0.001, respectively), and a 6.2% increase in CAF (P = 0.009) but improved SPPB balance score (P = 0.007). NfL concentration did not change in either group. In the population, negative correlations between changes in CAF concentration and SPPB total score were found (P = 0.047), whereas no correlation between NfL and SPPB variations was observed.

CONCLUSIONS

The present findings suggest that our 2-year mixed aerobic, strength and balance training seemed effective for preventing the age and sarcopenia-related increases in CAF concentration, preserving NMJ stability as well as muscle structure (PA and Lf) and improving physical performance in sarcopenic older individuals.

Identification of novel pathways and immune profiles related to sarcopenia

Introduction

Sarcopenia is a progressive deterioration of skeletal muscle mass strength and function.

Methods

To uncover the underlying cellular and biological mechanisms, we studied the association between sarcopenia's three stages and the patient's ethnicity, identified a gene regulatory network based on motif enrichment in the upregulated gene set of sarcopenia, and compared the immunological landscape among sarcopenia stages.

Results

We found that sarcopenia (S) was associated with GnRH, neurotrophin, Rap1, Ras, and p53 signaling pathways. Low muscle mass (LMM) patients showed activated pathways of VEGF signaling, B-cell receptor signaling, ErbB signaling, and T-cell receptor signaling. Low muscle mass and physical performance (LMM_LP) patients showed lower enrichment scores in B-cell receptor signaling, apoptosis, HIF-1 signaling, and the adaptive immune response pathways. Five common genes among DEGs and the elastic net regression model, TTC39DP, SLURP1, LCE1C, PTCD2P1, and OR7E109P, were expressed between S patients and healthy controls. SLURP1 and LCE1C showed the highest expression levels among sarcopenic Chinese descent than Caucasians and Afro-Caribbeans. Gene regulatory analysis of top upregulated genes in S patients yielded a top-scoring regulon containing GATA1, GATA2, and GATA3 as master regulators and nine predicted direct target genes. Two genes were associated with locomotion: POSTN and SLURP1. TTC39DP upregulation was associated with a better prognosis and stronger immune profile in S patients. The upregulation of SLURP1 and LCE1C was associated with a worse prognosis and weaker immune profile.

Conclusion

This study provides new insight into sarcopenia's cellular and immunological prospects and evaluates the age and sarcopenia-related modifications of skeletal muscle.

Prevalence and risk factors of sarcopenia without obesity and sarcopenic obesity among Chinese community older people in suburban area of Shanghai: A cross-sectional study

Objectives

The aim of the present study was to explore the prevalence and risk factors of sarcopenia without obesity (S) and sarcopenic obesity (SO) among community-dwelling older people in the Chongming District of Shanghai, China, according to the Asian Working Group for Sarcopenia (AWGS) 2019 Consensus as the diagnostic criteria of sarcopenia.

Methods

In this cross-sectional study, a total of 1,407 subjects aged ≥65 years were included, where the mean age of the subjects was 71.91 ± 5.59 years and their mean body mass index (BMI) was 24.65 ± 3.32 kg/m². According to the Asian Working Group for Sarcopenia (AWGS) 2019 Consensus, sarcopenia was defined as a low appendicular skeletal muscle mass index (≤7.0 kg/m² in males and ≤5.7 kg/m² in females), decreased handgrip strength (<28.0 kg in males and <18.0 kg in females), and/or low gait speed (<1.0 m/s) or poor 5-time chair stand test (5CST) (≥12s). The SO met both the diagnostic criteria for sarcopenia and obesity, meanwhile obesity was defined as an increased percentage of body fat (PBF) (≥25% in males and ≥35% in females). Univariate and multiple logistic regression analyses were performed to explore the risk factors of both S and SO.

Results

The prevalence of S and SO was 9.74% (M: 9.29%, F: 10.05%) and 9.95% (M: 13.94%, F: 7.14%). Lower BMI (OR = 0.136, 95% CI: 0.054-0.340, p < 0.001), lower hip circumference (OR = 0.858, 95% CI: 0.816-0.903, p < 0.001), farming (OR = 1.632, 95% CI: 1.053-2.530, p = 0.028), higher high-density lipoprotein cholesterol (HDL-C) level (OR = 2.235, 95% CI: 1.484-3.367, p < 0.001), and a sleep duration <7 h (OR = 0.561, 95% CI: 0.346-0.909, p = 0.019) were risk factors for S. While aging (70-74 y, OR = 1.923, 95% CI: 1.122-3.295, p = 0.017; 75-79 y, OR = 3.185, 95% CI: 1.816-5.585, p < 0.001; ≥80 y, OR = 7.192, 95% CI: 4.133-12.513, p < 0.001), male (OR = 1.981, 95% CI: 1.351-2.904, p < 0.001), higher BMI (OR = 4.865, 95% CI: 1.089-21.736, p = 0.038), higher monocyte level (OR = 4.203, 95% CI: 1.340-13.181, p = 0.014), and a sleep duration >9 h (OR = 1.881, 95% CI: 1.117-3.166, p = 0.017) were risk factors for SO.

Conclusion

Our study showed the high prevalence of S and SO among community-dwelling older people in the Chongming District. The SO was more prevalent in males. Behavioral factors and lifestyle (such as farming and sleep duration) were associated more with the development of S, while age and male gender were associated more with the development of SO.

Serum vitamin D status and circulating irisin levels in older adults with sarcopenia

Background

Emerging evidence suggests sarcopenia, which is involved in the serum vitamin D deficiency and development of abnormal muscle metabolism, is predominately centered in the general older population. In the present study, we aimed to explore the relationship between the level of serum vitamin D and irisin concentrations in the older adults with sarcopenia.

Methods

A cross-sectional study was conducted which included 422 sarcopenia participants (146 males and 276 females). Sarcopenia was assessed according to the recommended diagnostic criteria of the Asia Working Group for Sarcopenia (AWGS). The levels of serum 25-hydroxyvitamin D (25(OH)D), 25-hydroxyvitamin D₂ (25(OH)D₂) and 25-hydroxyvitamin D₃ (25(OH)D₃) were determined by LC-MS/MS. Irisin levels were measured by enzyme-linked immunosorbent assay (ELISA). The relationship between serum concentration of vitamin D and irisin were determined using multiple linear regression analysis.

Results

After adjustment for potential confounding factors, a significant and positive relationship between changes in irisin across 25(OH)D, and 25(OH)D₃ was observed (standard regression coefficients of 0.150 and 0.151, respectively, P < 0.05). However, no significant relationship was observed between serum vitamin D concentrations and irisin levels in males.

Conclusions

This study demonstrated that a higher level of serum vitamin D is independently related to the increment of irisin in sarcopenia females, not in males. These investigations need to be verified in other large-scale prospective studies.

A BDNF-TrkB autocrine loop enhances senescent cell viability

Cellular senescence is characterized by cell cycle arrest, resistance to apoptosis, and a senescence-associated secretory phenotype (SASP) whereby cells secrete pro-inflammatory and tissue-remodeling factors. Given that the SASP exacerbates age-associated pathologies, some aging interventions aim at selectively eliminating senescent cells. In this study, a drug library screen uncovered TrkB (NTRK2) inhibitors capable of triggering apoptosis of several senescent, but not proliferating, human cells. Senescent cells expressed high levels of TrkB, which supported senescent cell viability, and secreted the TrkB ligand BDNF. The reduced viability of senescent cells after ablating BDNF signaling suggested an autocrine function for TrkB and BDNF, which activated ERK5 and elevated BCL2L2 levels, favoring senescent cell survival. Treatment with TrkB inhibitors reduced the accumulation of senescent cells in aged mouse organs. We propose that the activation of TrkB by SASP factor BDNF promotes cell survival and could be exploited therapeutically to reduce the senescent-cell burden.

Association between serum GDF-15, myostatin, and sarcopenia in cardiovascular surgery patients

Background

Myostatin is a negative regulator of skeletal muscle mass. On the other hand, growth differentiation factor (GDF)-15 is associated with lower muscle strength and muscle mass. We investigated the relationship between serum GDF-15, myostatin, and sarcopenia in patients receiving cardiovascular surgery through a ROC curve and a multivariate regression analysis.

Methods

Skeletal muscle mass index (SMI) by bioelectrical impedance analysis, hand-grip strength, knee extension strength, and walking speed were measured. Preoperative serum GDF-15 and myostatin levels were determined by ELISA. The sarcopenia index could be expressed as: −0.0042 × [myostatin] + 0.0007 × [GDF-15] + 0.0890 × age + 1.4030 × sex − 0.2679 × body mass index (BMI) − 2.1186. A ROC curve was plotted to identify the optimal cutoff level of the sarcopenia index to detect sarcopenia.

Results

120 patients receiving cardiovascular surgery were included in the study. SMI, hand-grip strength, knee extension strength, and walking speed inversely correlated with GDF-15, but positively correlated with myostatin. In the multivariate stepwise regression analysis, SMI was a determinant of myostatin, and both GDF-15 and myostatin were determinants of SMI and muscle thickness, even after adjustment for age, sex, and BMI. A ROC curve showed that the sarcopenia index was a determinant of sarcopenia (cutoff value −1.0634, area under the curve 0.901, sensitivity 96.9%, specificity 70.9%).

Conclusion

GDF-15 and myostatin are associated with skeletal muscle volume in patients receiving cardiovascular surgery, but these associations are different. The sarcopenia index calculated from GDF-15 and myostatin levels may be a biomarker of sarcopenia.

Associations of Dynapenic Obesity and Sarcopenic Obesity with the Risk of Complications in COVID-19

Ageing is associated with changes in body composition, such as low muscle mass (sarcopenia), decreased grip strength or physical function (dynapenia), and accumulation of fat mass. When the accumulation of fat mass synergistically accompanies low muscle mass or reduced grip strength, it results in sarcopenic obesity and dynapenic obesity, respectively. These types of obesity contribute to the increased risk of cardiovascular disease and mortality in the elderly, which could increase the damage caused by COVID-19. In this review, we associated factors that could generate a higher risk of COVID-19 complications in dynapenic obesity and sarcopenic obesity. For example, skeletal muscle regulates the expression of inflammatory cytokines and supports metabolic stress in pulmonary disease; hence, the presence of dynapenic obesity or sarcopenic obesity could be related to a poor prognosis in COVID-19 patients.

New Horizons in the Treatment of Age-Associated Obesity, Sarcopenia and Osteoporosis

The rapid increase in both the lifespan and proportion of older adults in developed countries is accompanied by the dramatic growth of age-associated chronic diseases, including obesity, sarcopenia, and osteoporosis. Hence, prevention and treatment of age-associated chronic diseases has become increasingly urgent. The key to achieving this goal is a better understanding of the mechanisms underlying their pathophysiology, some aspects of which, despite extensive investigation, are still not fully understood. Aging, obesity, sarcopenia, and osteoporosis are characterized by the creation of a systemic, chronic, low-grade inflammation (SCLGI). The common mechanisms that govern the development of these chronic conditions include a failed resolution of inflammation. Physiologically, the process of inflammation resolution is provided mainly by specialized pro-resolving mediators (SPMs) acting via cognate G protein-coupled receptors (GPCRs). Noteworthy, SPM levels and the expression of their receptors are significantly reduced in aging and the associated chronic disorders. In preclinical studies, supplementation of SPMs or their stable, small-molecule SPM mimetics and receptor agonists reveals clear beneficial effects in inflammation-related obesity and sarcopenic and osteoporotic conditions, suggesting a translational potential. Age-associated chronic disorders are also characterized by gut dysbiosis and the accumulation of senescent cells in the adipose tissue, skeletal muscle, and bones. Based on these findings, we propose SCLGI resolution as a novel strategy for the prevention/treatment of age-associated obesity, sarcopenia, and osteoporosis. Our approach entails the enhancement of inflammation resolution by SPM mimetics and receptor agonists in concert with probiotics/prebiotics and compounds that eliminate senescent cells and their pro-inflammatory activity.

Targeted proteomics of appendicular skeletal muscle mass and handgrip strength in black South Africans: a cross-sectional study

Although appendicular skeletal muscle mass (ASM) and handgrip strength (HGS) are key components of sarcopenia, their underlying biological mechanisms remain poorly understood. We aimed to investigate associations of circulating biomarkers with ASM and HGS in middle-aged black South Africans. This study consisted of 934 black South Africans (469 men and 465 women, aged 41-72 years) from the Middle-aged Soweto cohort. Linear regression models were used to examine relationships between 182 biomarkers (measured with proximity extension assay) and dual-energy X-ray absorptiometry-measured ASM and dynamometer-measured HGS. Age, height, sex, smoking, alcohol, food insecurity, physical activity, visceral adipose tissue, HIV and menopausal status were included as confounders. Regression models showing sex-interactions were stratified by sex. The Benjamini-Hochberg false discovery rate (FDR) was used to control for multiple testing, and FDR-adjusted P values were reported. In the total sample, 10 biomarkers were associated with higher ASM and 29 with lower ASM (P < 0.05). Out of these 39 biomarkers, 8 were also associated with lower HGS (P < 0.05). MMP-7 was associated with lower HGS only (P = 0.011) in the total sample. Sex-interactions (P < 0.05) were identified for 52 biomarkers for ASM, and 6 for HGS. For men, LEP, MEPE and SCF were associated with higher ASM (P < 0.001, = 0.004, = 0.006, respectively), and MEPE and SCF were also associated with higher HGS (P = 0.001, 0.012, respectively). Also in men, 37 biomarkers were associated with lower ASM (P < 0.05), with none of these being associated with lower HGS. Furthermore, DLK-1 and MYOGLOBIN were associated with higher HGS only (P = 0.004, 0.006, respectively), while GAL-9 was associated with lower HGS only (P = 0.005), among men. For women, LEP, CD163, IL6, TNF-R1 and TNF-R2 were associated with higher ASM (P < 0.001, = 0.014, = 0.027, = 0.014, = 0.048, respectively), while IGFBP-2, CTRC and RAGE were associated with lower ASM (P = 0.043, 0.001, 0.014, respectively). No biomarker was associated with HGS in women. In conclusion, most biomarkers were associated with ASM and not HGS, and the associations of biomarkers with ASM and HGS displayed sex-specificity in middle-aged black South Africans. Proteomic studies should examine ASM and HGS individually. Future research should also consider sexual dimorphism in the pathophysiology of sarcopenia for development of sex-specific treatment and diagnostic methods.

Relationship between the serum GDF-15 concentration and muscle function in female patients receiving aortic valve replacement (TAVR, SAVR): Comparison with healthy elderly female subjects

Purpose

Methods

Results

Conclusions

Plasma levels of myokines and inflammatory markers are related with functional and respiratory performance in older adults with COPD and sarcopenia

This study investigated whether blood-based biomarkers were related to functional test performance and respiratory muscle strength in older adults with COPD and sarcopenia. The participants included in this cross-sectional study were from both sexes and sixty years or older. Based on clinical assessment, participants were categorized in COPD (n = 43) and non-COPD (NCOPD) (n = 43) groups. They were also assessed for body composition and muscular mass by dual-energy X-ray absorptiometry, using the relative skeletal muscle index for the diagnosis of sarcopenia. A series of functional tests, including short physical performance battery (SPPB), 6-minute walking test (6MWT), maximal inspiratory and expiratory pressures (MIP and MEP), were carried out. Plasma levels of myokines (Irisin and BDNF), and soluble TNF receptors (sTNFR1 and sTNFR2) were determined by ELISA. In the multivariate analysis, 6MWD was associated with age, COPD-related sarcopenia and BDNF (R² = 0.29; f² = 0.41). SPPB score was associated with COPD-related sarcopenia and sTNFR1 (R² = 0.25; f² = 0.33). MIP value was associated with sex, COPD-related sarcopenia, sTNFR2 and Irisin (R² = 0.24; f² = 0.31). Finally, MEP value was associated with sex COPD-related sarcopenia (R² = 0.18; f² = 0.22). Plasma levels of myokines and inflammatory markers are related with functional and respiratory performance in older adults with COPD and sarcopenia.

A combined diagnostic approach based on serum biomarkers for sarcopenia in older patients with hip fracture

OBJECTIVE

To develop prediction models for sarcopenia in older patients with hip fracture based on a specific set of serum biomarkers aimed at estimating appendicular skeletal muscle mass and diagnosing sarcopenia.

METHODS

Older patients with hip fracture admitted to the First Affiliated Hospital of Wenzhou Medical University from January 2020 to June 2021 were recruited, screened for sarcopenia and tested for peripheral blood levels of specific serum biomarkers preoperatively. Participants were randomly divided into a training set and test set. Common factors were extracted from selected biomarkers through factor analysis, and regression models were established in the training set and verified in the test set.

RESULTS

A total of 212 patients were enrolled, and the prevalence of sarcopenia was 22.8% in men and 19.5% in women. Significant differences in cystatin C, estimated glomerular filtration rate based on cystatin C, sarcopenia index, new sarcopenia index, haemoglobin and albumin were observed between patients with and without sarcopenia. Two regression models were developed in the training set. The validation of the test set confirmed that the linear regression model showed good consistency in predicting appendicular skeletal muscle mass index, while the logistic regression model showed high accuracy in predicting sarcopenia.

CONCLUSIONS

Both prediction models exhibited potential clinical application value for estimating appendicular skeletal muscle mass and predicting sarcopenia in older patients with hip fracture, providing new insights into the serological diagnosis of sarcopenia.

Multi-omics research in sarcopenia: Current progress and future prospects

Sarcopenia is a systemic disease with progressive and generalized skeletal muscle dysfunction defined by age-related low muscle mass, high content of muscle slow fibers, and low muscle function. Muscle phenotypes and sarcopenia risk are heritable; however, the genetic architecture and molecular mechanisms underlying sarcopenia remain largely unclear. In recent years, significant progress has been made in determining susceptibility loci using genome-wide association studies. In addition, recent advances in omics techniques, including genomics, epigenomics, transcriptomics, proteomics, and metabolomics, offer new opportunities to identify novel targets to help us understand the pathophysiology of sarcopenia. However, each individual technology cannot capture the entire view of the biological complexity of this disorder, while integrative multi-omics analyses may be able to reveal new insights. Here, we review the latest findings of multi-omics studies for sarcopenia and provide an in-depth summary of our current understanding of sarcopenia pathogenesis. Leveraging multi-omics data could give us a holistic understanding of sarcopenia etiology that may lead to new clinical applications. This review offers guidance and recommendations for fundamental research, innovative perspectives, and preventative and therapeutic interventions for sarcopenia.

Protein interventions augment the effect of resistance exercise on appendicular lean mass and handgrip strength in older adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Increased protein intake is suggested as a strategy to slow or reverse the loss of muscle mass and strength observed in sarcopenia, but results from studies that directly tested this possibility have been inconsistent.

OBJECTIVES

We assessed the evidence on the effects of whole protein supplementation or higher-protein diets, without the use of amino acids or supplements known to stimulate hypertrophy, alone or in combination with resistance exercise (RE) interventions, on lean body mass (LBM) and strength in older adults.

METHODS

A systematic search was conducted using PubMed, Medline, Web of Science, and Cochrane CENTRAL databases from January 1990 to July 2021. Randomized controlled trials that assessed the effects of protein supplementation and/or higher-protein dietary interventions in older adults (mean age ≥50 y) on total LBM, appendicular lean mass (ALM), and handgrip (HG) and knee extension (KE) strength were included.

RESULTS

Twenty-eight studies were identified. In pooled analysis, compared with lower protein controls, protein supplementation did not have a significant positive effect on total LBM [weighted mean difference in change (WMD): 0.34; 95% CI: -0.21, 0.89; I2 = 90.01%], ALM (WMD: 0.4; 95% CI: -0.01, 0.81; I2 = 90.38%), HG strength (WMD: 0.69; 95% CI: -0.69, 2.06; I2 = 94.52%), or KE strength (WMD: 1.88; 95% CI: -0.6, 4.35; I2 = 95.35%). However, in interventions that used also RE, statistically significant positive effects of protein were observed for ALM (WMD: 0.54; 95% CI: 0.03, 1.05; I2 = 89.76%) and HG (WMD: 1.71; 95% CI: 0.12, 3.30; I2 = 88.71%). Meta-regression revealed no significant association between age, per-meal protein dose, duration, and baseline protein intake with change in any outcome. Subgroup analysis revealed the statistically significant effects on ALM occurred only in sarcopenic/frail populations (WMD: 0.88; 95% CI: 0.51, 1.25; I2 = 79.0%). Most studies (n = 22) had some risk of bias.

CONCLUSIONS

In older adults performing RE, increased protein intake leads to greater ALM and HG strength compared with lower protein controls. Without RE, protein has no additional benefit on changes in total LBM, ALM, or HG strength.

Ultrasonic Elastography of the Rectus Femoris, a Potential Tool to Predict Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Purpose: Skeletal muscle dysfunction is common in patients with chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. Abnormal muscle quantity of the lower limbs is a manifestation of skeletal muscle dysfunction in patients with COPD. Shear wave ultrasound elastography (SWE) is a novel and possible tool to evaluate qualitative muscle parameters. This study explores the feasibility of SWE to measure the stiffness of the rectus femoris and evaluates its value in predicting sarcopenia in patients with COPD.

Methods: Ultrasound examination of the rectus femoris was performed to determine the mean elasticity index (SWE_mean), cross-sectional area (RF_csa), and thickness (RF_thick) using grayscale ultrasonography (US) and SWE in 53 patients with COPD and 23 age-matched non-COPD healthy controls. The serum levels of circulating biomarkers (GDF15, resistin, and TNF-α) were measured using ELISA. The definition of sarcopenia followed the guidelines from the Asian Working Group for Sarcopenia. Receiver operating characteristic (ROC) curve analysis of the SWE_mean, RF_thick, and RF_csa was used to evaluate their predictive ability for sarcopenia.

Results: The intraobserver and interobserver repeatability of SWE performance was excellent (all correlation coefficients > 0.95; p < 0.05). The SWE_mean of the rectus femoris in patients with COPD (8.98 ± 3.12 kPa) was decreased compared with that in healthy controls (17.00 ± 5.14 kPa) and decreased with advanced global initiative for chronic obstructive lung disease (GOLD) stage. Furthermore, SWE_mean was found to be independent of sex, height, and body mass, and a lower SWE_mean in patients with COPD was positively associated with reduced pulmonary function, worse physical function, poor exercise tolerance, decreased muscle strength, and worse dyspnea index score. The correlation between physical function [five-repetition sit-to-stand test (5STST)], muscle function, and SWE_mean was higher than those of RF_thick and RF_csa. In addition, SWE_mean was negatively correlated with serum GDF15 levels (r = −0.472, p < 0.001), serum resistin levels (r = −0.291, p = 0.035), and serum TNF-α levels (r = −0.433, p = 0.001). Finally, the predictive power of SWE_mean [area under the curve (AUC): 0.863] in the diagnosis of sarcopenia was higher than that of RF_thick (AUC: 0.802) and RF_csa (AUC: 0.816).

Conclusion: Compared with grayscale US, SWE was not affected by the patient’s height, weight, or BMI and better represented skeletal muscle function and physical function. Furthermore, SWE is a promising potential tool to predict sarcopenia in patients with COPD.

Multifactorial Mechanism of Sarcopenia and Sarcopenic Obesity. Role of Physical Exercise, Microbiota and Myokines

Obesity and ageing place a tremendous strain on the global healthcare system. Age-related sarcopenia is characterized by decreased muscular strength, decreased muscle quantity, quality, and decreased functional performance. Sarcopenic obesity (SO) is a condition that combines sarcopenia and obesity and has a substantial influence on the older adults’ health. Because of the complicated pathophysiology, there are disagreements and challenges in identifying and diagnosing SO. Recently, it has become clear that dysbiosis may play a role in the onset and progression of sarcopenia and SO. Skeletal muscle secretes myokines during contraction, which play an important role in controlling muscle growth, function, and metabolic balance. Myokine dysfunction can cause and aggravate obesity, sarcopenia, and SO. The only ways to prevent and slow the progression of sarcopenia, particularly sarcopenic obesity, are physical activity and correct nutritional support. While exercise cannot completely prevent sarcopenia and age-related loss in muscular function, it can certainly delay development and slow down the rate of sarcopenia. The purpose of this review was to discuss potential pathways to muscle deterioration in obese individuals. We also want to present the current understanding of the role of various factors, including microbiota and myokines, in the process of sarcopenia and SO.

A neuromuscular perspective of sarcopenia pathogenesis: deciphering the signaling pathways involved

The escalation of life expectancy is accompanied by an increase in the prevalence of age-related conditions, such as sarcopenia. Sarcopenia, a muscle condition defined by low muscle strength, muscle quality or quantity, and physical performance, has a high prevalence among the elderly and is associated to increased mortality. The neuromuscular system has been emerging as a key contributor to sarcopenia pathogenesis. Indeed, the age-related degeneration of the neuromuscular junction (NMJ) function and structure may contribute to the loss of muscle strength and ultimately to the loss of muscle mass that characterize sarcopenia. The present mini-review discusses important signaling pathways involved in the function and maintenance of the NMJ, giving emphasis to the ones that might contribute to sarcopenia pathogenesis. Some conceivable biomarkers, such as C-terminal agrin fragment (CAF) and brain-derived neurotrophic factor (BDNF), and therapeutic targets, namely acetylcholine and calcitonin gene-related peptide (CGRP), can be retrieved, making way to future studies to validate their clinical use.

Putative Candidate Drug Targets for Sarcopenia-Related Traits Identified Through Mendelian Randomization Analysis of the Blood Proteome

Purpose: The increasing prevalence of sarcopenia remains an ongoing challenge to health care systems worldwide. The lack of treatments encouraged the discovery of human proteomes to find potential therapeutic targets. As one of the major components of the human proteome, plasma proteins are functionally connected with various organs of the body to regulate biological processes and mediate overall homeostasis, which makes it crucial in various complex processes such as aging and chronic diseases. By performing a systematic causal analysis of the plasma proteome, we attempt to reveal the etiological mechanism and discover drug targets for sarcopenia. Methods: By using data from four genome-wide association studies for blood proteins and the UK Biobank data for sarcopenia-related traits, we applied two-sample Mendelian randomization (MR) analysis to evaluate 310 plasma proteins as possible causal mediators of sarcopenia-related traits: appendicular lean mass (ALM) and handgrip strength (right and left). Then we performed a two-sample bidirectional Mendelian randomization analysis for the identified putatively causal proteins to assess potential reverse causality that the trait values may influence protein levels. Finally, we performed phenome-wide MR analysis of the identified putatively causal proteins for 784 diseases to test the possible side effects of these proteins on other diseases. Results: Five plasma proteins were identified as putatively causal mediators of sarcopenia-related traits. Specifically, leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2), asporin (ASPN), and contactin-2 (CNTN2) had potential causal effects on appendicular lean mass, and ecto-ADP-ribosyltransferase 4 (ART4) and superoxide dismutase 2 (SOD2) had putative causal effects on the handgrip strength, respectively. None of the five putatively causal proteins had a reverse causality relationship with sarcopenia-related traits, and no side effects on other diseases were identified. Conclusion: We identified five plasma proteins that may serve as putatively potential novel drug targets for sarcopenia. Our study attested to the value of two-sample MR analysis in identifying and prioritizing putatively potential therapeutic targets for complex diseases.

Psoriasis Is Associated With Myosteatosis but Not Sarcopenia: A Case-Control Study

Background: The link between psoriasis and body fat (or obesity) has been well established. However, there are no reports detailing the possible relationship between psoriasis and fat infiltration in skeletal muscle, also known as myosteatosis. A recent study reported the possible association between psoriasis, arthritis, and sarcopenia (the loss of skeletal muscle mass or function). The present study aimed to explore the possible associations of chronic plaque psoriasis with myosteatosis and sarcopenia.

Methods: We conducted a case-control study. In-patients with chronic plaque psoriasis were retrospectively recruited. Healthy controls were prospectively and continuously recruited. Unenhanced cross-sectional chest computed tomography images at the 12th thoracic vertebral level were analyzed using Mimics software. Skeletal muscle area (SMA), skeletal muscle radiodensity (SMD), and intermuscular adiposity tissue (IMAT) were measured. The skeletal muscle index (SMI) was calculated as SMA/height². The percentage of IMAT (IMAT%) was calculated as IMAT/SMA × 100%. Myosteatosis was defined by SMD or IMAT%, whereas sarcopenia was defined by SMI. Propensity score matching was performed to adjust for the main confounders. Logistic regression models were used to evaluate the associations of psoriasis with myosteatosis and sarcopenia.

Results: We included 155 psoriasis patients and 512 healthy controls. After propensity score matching, we retained 310 controls. The prevalence of sarcopenia was not significantly different between the psoriasis and control groups (men: 9.8% vs. 14.4%, p = 0.244; women: 7.0% vs. 11.7%, p = 0.548). Psoriasis patients were more prone to SMD-defined myosteatosis (men: 39.3% vs. 20.8%; women: 46.5% vs. 16.0%; both p < 0.001) and IMAT%-defined myosteatosis (men: 21.4% vs. 12.5%, p = 0.034; women: 46.5 vs. 28.7%, p = 0.042) than the control group. After adjustment for potential confounders, psoriasis was not significantly associated with sarcopenia (odds ratio [OR] 0.51, 95% confidence interval [CI] 0.25–1.19, p = 0.136). However, psoriasis was associated with SMD-defined myosteatosis (OR 3.16, 95% CI 1.86–5.37, p < 0.001) and IMAT%-defined myosteatosis (OR 1.76, 95% CI 1.04–3.00; p = 0.037).

Conclusions: Chronic plaque psoriasis is independently associated with myosteatosis but not sarcopenia. Since fat and muscle are considered endocrine organs and can drive the inflammatory process, further studies detailing the interaction between psoriasis, fat, and skeletal muscle are warranted.

Feasibility of a high-PRotein Mediterranean-style diet and resistance Exercise in cardiac Rehabilitation patients with sarcopenic obesity (PRiMER): Study protocol for a randomised control trial

BACKGROUND

Cardiac rehabilitation (CR) is an essential component of long-term recovery following a cardiac event. Typical CR may not be optimal for patients presenting with sarcopenic obesity (SO) who present with reduced muscle mass and elevated adipose tissue, and may indicate greater cardiovascular disease (CVD) risk. Resistance exercise and high-protein diets are known to increase muscle mass, while Mediterranean-style diets have been shown to reduce CVD risk. A high-protein Mediterranean-style diet combined with resistance exercise intervention is yet to be trialled in cardiac rehabilitation populations.

OBJECTIVES

Primary outcome: to determine the feasibility of such an intervention by investigating the perceptions, acceptance and adherence to a resistance exercise protocol and high-protein Mediterranean style diet in a UK cardiac rehabilitation population with SO. Secondary outcome: to trial this protocol ahead of a fully powered clinical study.

METHODS

Eligible cardiac rehabilitation patients will be randomised to one of the following: 1) a control group (standard CR), 2) high-protein Mediterranean-style diet, 3) resistance exercise group, or 4) both high-protein Mediterranean-style diet and resistance exercise group. The pilot study will last 12 weeks. Measures of body composition (dual energy x-ray absorptiometry) grip strength, CVD risk (e.g., fasting triglycerides, glucose, cholesterol) and dietary adherence will be assessed at baseline and after 12 weeks. To compare groups, a mixed model ANOVA (time x intervention) will be performed. Patient participant involvement throughout the development of this project will be used to determine the feasibility of a future, fully powered, randomised control trial. A feasibility questionnaire will help establish the proportion of eligible participants, their willingness to be randomised, response rates, and ethical considerations. Furthermore, focus groups, food tasting and telephone interviews will be conducted to assess the acceptability of recipes and exercise protocols provided.

DISCUSSION

This pilot trial will determine whether a fully powered, multi-centred randomised control trial in CR patients with SO can be implemented. The information received from patient involvement will be invaluable for identifying possible barriers to participation and tailoring interventions to participant needs, helping to increase the likelihood of long-term compliance to health-promoting lifestyle changes.

REGISTRATION

This study is registered at clinicaltrials.gov (NCT04272073), registered on 17/02/2020, https://clinicaltrials.gov/ct2/show/NCT04272073.

DATE AND VERSION

28/12/20 version 3.0.

Sarcopenia: Etiology, Nutritional Approaches, and miRNAs

Sarcopenia, an age-related decline in skeletal muscle mass and function, dramatically affects the quality of life. Although there is a consensus that sarcopenia is a multifactorial syndrome, the etiology and underlying mechanisms are not yet delineated. Moreover, research about nutritional interventions to prevent the development of sarcopenia is mainly focused on the amount and quality of protein intake. The impact of several nutrition strategies that consider timing of food intake, anti-inflammatory nutrients, metabolic control, and the role of mitochondrial function on the progression of sarcopenia is not fully understood. This narrative review summarizes the metabolic background of this phenomenon and proposes an integral nutritional approach (including dietary supplements such as creatine monohydrate) to target potential molecular pathways that may affect reduce or ameliorate the adverse effects of sarcopenia. Lastly, miRNAs, in particular those produced by skeletal muscle (MyomiR), might represent a valid tool to evaluate sarcopenia progression as a potential rapid and early biomarker for diagnosis and characterization.

From Exercise to Cognitive Performance: Role of Irisin

The beneficial effects of exercise on the brain are well known. In general, exercise offers an effective way to improve cognitive function in all ages, particularly in the elderly, who are considered the most vulnerable to neurodegenerative disorders. In this regard, myokines, hormones secreted by muscle in response to exercise, have recently gained attention as beneficial mediators. Irisin is a novel exercise-induced myokine, that modulates several bodily processes, such as glucose homeostasis, and reduces systemic inflammation. Irisin is cleaved from fibronectin type III domain containing 5 (FNDC5), a transmembrane precursor protein expressed in muscle under the control of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). The FNDC5/irisin system is also expressed in the hippocampus, where it stimulates the expression of the neurotrophin brain-derived neurotrophic factor in this area that is associated with learning and memory. In this review, we aimed to discuss the role of irisin as a key mediator of the beneficial effects of exercise on synaptic plasticity and memory in the elderly, suggesting its roles within the main promoters of the beneficial effects of exercise on the brain.

Active older dancers have lower C-terminal Agrin fragment concentration, better balance and gait performance than sedentary peers

Motor neuron degeneration, denervation, neuromuscular junction (NMJ) fragmentation and loss of motor units (MUs), play a key-role in the development of sarcopenia. The aim of the present study was to investigate the beneficial effects of regular practice of dancing in physically active elders on concentration of C-terminal Agrin fragment (CAF), a marker of NMJ instability, muscle mass, strength, and physical performance in a group of 16 recreationally active older dancers (AOD; 70.1 ± 3.4 yr) compared to 15 age-matched sedentary peers (OS; 70.9 ± 6.2 yr). Circulating concentration of CAF was measured in serum, while morphology of the vastus lateralis and multifidus muscles was assessed by ultrasound imaging. In addition, the participants underwent two functional performance tests, the Timed Up and Go (TUG) and the 10-meter walk test (10-MWT), a lower and upper limb isometric strength test, a static and a dynamic balance test. Although no statistically significant differences were detected for both muscle morphology and isometric strength, higher CAF concentration (20%, p < 0.01) was found in OS. AOD showed a better performance in TUG (22%, p < 0.001), 10-MWT (17%, p < 0.001) and dynamic balance (25%, p < 0.01) than OS. Notably, CAF concentration correlated with dynamic balance performance (r = 0.3711, p < 0.05). Our results provide evidence that the regular practice of dancing in older age, together with non-structured light aerobic physical activities, is associated to lower CAF concentration and improved walking and balance performance. Our findings also suggest that NMJ instability, as indicated by elevated CAF serum concentration, seems to precede the loss of muscle size and alterations in muscle architecture normally associated with sarcopenia.

Irisin is a predictor of sarcopenic obesity in type 2 diabetes mellitus: A cross-sectional study

We aimed to evaluate sarcopenia and sarcopenic obesity (SO) in patients with type 2 diabetes mellitus (T2DM), possible relationships with serum irisin and myostatin levels, and the effect of glycemic control on SO.Ninety T2DM patients were included in this a cross-sectional study. Sarcopenia was determined by evaluating muscle mass (bioelectrical impedance analysis), muscle strength (HGS), and gait speed (GS). Patients with muscle mass loss with functionally reduced muscle strength and/or performance were considered sarcopenic. In addition, participants were divided into 3 groups according to the FM (fat mass)/FFM (fat-free mass) ratio [group 1:5th-50th percentiles; group 2:50th-95th percentiles and group 3: ≥95 percentiles (sarcopenic obese)]. Irisin, myostatin levels and metabolic parameters were measured in all patients.The prevalence of sarcopenia and SO was 25.6% and 35.6%, respectively. Irisin levels were lower in sarcopenic patients, while glycosylated hemoglobin (A1c), body mass index (BMI), FM, and FM index were higher (P < .05). From group 1 to group 3, BMI, FM, FM index, GS, myostatin, and A1c increased, and muscle mass percentage, HGS, and irisin decreased (P < .05). A positive correlation was found between FM/FFM and myostatin and a negative correlation between FM/FFM and irisin (r = 0.303, P = .004 vs. r = -0.491, P < .001). Irisin remained an important predictor of SO, even after adjusting for confounding variables (OR:1.105; 95% CI:0.965-1.338, P = .002). The optimal cut-off value for irisin to predict SO was 9.49 ng/mL (specificity = 78.1%, sensitivity = 75.8%). In addition, A1c was an independent risk factor for SO development (OR:1.358, P = .055).This study showed that low irisin levels (<9.49ng/mL) and poor glycemic control in T2DM patients were an independent risk factor, especially for SO.

Environmental Factors Affecting Early Mobilization and Physical Disability Post-Intensive Care: An Integrative Review Through the Lens of the World Health Organization International Classification of Functioning, Disability, and Health

BACKGROUND

Early mobilization (EM) is one of few potential protective factors associated with reduced physical disability post-intensive care (PD PIC). However, only 45% of intensive care units (ICUs) in the United States routinely practice EM despite its recognized benefits.

OBJECTIVES

To analyze the evidence on the relationship between critical care EM, PD PIC, and environmental factors, using the theoretical lens of the World Health Organization's (WHO's) International Classification of Functioning, Disability, and Health (ICF).

METHOD

The Whittemore and Knafl methodology for integrative reviews and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines were followed. Qualitative, quantitative, and mixed-methods studies (n = 38) that evaluated EM and 1 or more domains of the WHO ICF were included. Quality was appraised using the Mixed-Methods Appraisal Tool. Study characteristics were evaluated for common themes and relationships. The ICF domains and subdomains pertaining to each study were synthesized.

RESULTS

Early mobilization was related to improved functioning on the disability continuum of the WHO ICF. Early mobilization was influenced by several WHO ICF environmental factors. Dedicated physical and occupational therapy teams in the ICU, interdisciplinary rounds, and positive family and staff perception of EM facilitated intervention delivery. However, poor staffing levels, negative unit culture, perceived workload burden, and lack of equipment, education, and financial support impeded delivery of EM.

DISCUSSION

Early mobilization is a promising intervention that may reduce PD PIC. However, environmental factors negatively influence delivery of EM in the ICU. Several gaps in EM research limit its acceptability in ICU practice. Existing EM research is challenged by poor methodological quality. Further study is necessary to better understand the role of EM on PD PIC and improve patient outcomes following critical illness.

Serum sestrins: potential predictive molecule in human sarcopenia

BACKGROUND

The aging trajectory from a state of robustness and good health proceeds from sarcopenia to frailty followed by disability and death due to decline in skeletal muscle mass and function. Sarcopenia is now formally recognized as a muscle disease with an ICD-10-MC diagnosis code. The autophagic response seems to be affected in the skeletal muscle during aging contributing to sarcopenia. Sestrins (Sesns) proteins play a critical role in autophagy induction under cellular stress conditions.

AIMS

The study aims to identify sarcopenia in older adults using Asian Working group guidelines (AWGS) to determine clinically relevant cut-off levels for diagnosis and their association with antioxidant protein Sesns.

METHODS

The study recruited 102 older adults attending Geriatric medicine OPD AIIMS, New Delhi, India. The level of serum Sesns were evaluated by Surface Plasmon Resonance (SPR) and validated by immunoblotting. Fifty older adults were diagnosed as sarcopenics according to AWGS.

RESULTS

Sesn 1 (p = 0.0448) and Sesn 2 (p < 0.0001) levels were significantly reduced in sarcopenic compared to non-sarcopenic. ROC analysis showed a better cut-off of Sesn 2; 10.104 ng/µL with 92% sensitivity and 84% specificity. Even after adjusting the values with respect to confounding factors, Sesn levels remained significantly reduced in sarcopenics (p < 0.030).

DISCUSSION

The level of Sesn 2 showed positive co-relation with the characteristics of sarcopenia. This study first time reported the concentration of serum sestrin in sarcopenic older adults.

CONCLUSION

It can be concluded that sarcopenia can be diagnosed at the early stage by using the serum sestrin scale as one of the potential biomarker.

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.

2019 Marathon of Rome. Hamstring injuries in long distance runners: influence of age, gender, weight, height, numbers of marathon and impact profile

BACKGROUND

Hamstring diseases are one of the most widespread diseases in athletes, especially in runners, sprinters, and endurance athletes. Notwithstanding the importance of the problem, risk factors are still marginally known. This transversal study analyzes the correlation between Hamstring tendinopathy and hamstring strains and age, gender, weight, height, number of marathons, and impact profile in athletes who took part in the 2019 Rome Marathon.

METHODS

At the 2019 Marathon of Rome, 700 runners (484 males and 216 females; mean age: 43.6 years, range 17-80 years) filled the VISA-H and FASH questionnaires. An adequately skilled orthopedic surgeon made a diagnosis of Hamstring tendinopathy and Hamstring strain injuries in line with clinical criteria.

RESULTS

A diagnosis of Hamstring tendinopathy was made in 537 participants while in 624 of hamstring strains. There was evidence of a positive correlation statistically significant between age, weight and impact profile with Hamstring strain injuries, while there was no association between sex and number of marathons and the Hamstring strains. No statistically significant positive correlation was found between all of the parameters analyzed and VISA-H. The association between VISA-H score and FASH score has resulted statistically significant.

CONCLUSIONS

In marathon athletes, there was not found evidence of a statistically significant correlation between gender, weight, height, number of marathons, impact profile and Hamstring tendinopathy. Nonetheless, age, weight and impact profile were associated with Hamstring strains, while sex and number of marathons had not shown statistically significant positive association with Hamstring strain injuries.