Sarcopenia: Current treatments and new regenerative therapeutic approaches

New Insight in Using of Mesenchyme Stem Cell Conditioning Medium for the Impaired Muscle related Biomarkers: In vivo Study with Rat Model

AIMS AND OBJECTIVES

This study aimed to investigate the effects of Umbilical Cord Mesencymal Stem Cell Conditioning Medium (UC MSC-CM) administration on body weight recovery and the level of four molecular biomarkers, namely Superoxide Dismutase (SOD), vascular Endothelial Growth Factor (VEGF), C-Reactive Protein (CRP), and myostatin.

MATERIALS AND METHODS

Secretome was injected intramuscularly twice at 1.5 mL (day 7 and 14) into the right thigh of high-dose, short-term galactose-induced aging rats. The data of day 7 (before) and day 21 (after the administration) were evaluated. The body weights and the four biomarkers were measured before (day 7) and after intervention (day 21).

RESULTS

This study showed that the UC MSC-CM intramuscular administrations did not influence body weight regeneration. However, it could increase SOD and VEGF levels and decrease CRP and myostatin levels.

CONCLUSION

Treatment with UC MSC-CM is a promising and potential agent in treating sarcopenia.

Harnessing immunomodulation to combat sarcopenia: current insights and possible approaches

Sarcopenia is a complex age-associated syndrome of progressive loss of muscle mass and strength. Although this condition is influenced by many factors, age-related changes in immune function including immune cell dynamics, and chronic inflammation contribute to its progression. The complex interplay between the immune system, gut-muscle axis, and autophagy further underscores their important roles in sarcopenia pathogenesis. Immunomodulation has emerged as a promising strategy to counteract sarcopenia. Traditional management approaches to treat sarcopenia including physical exercise and nutritional supplementation, and the emerging technologies of biophysical stimulation demonstrated the importance of immunomodulation and regulation of macrophages and T cells and reduction of chronic inflammation. Treatments to alleviate low-grade inflammation in older adults by modulating gut microbial composition and diversity further combat sarcopenia. Furthermore, some pharmacological interventions, nano-medicine, and cell therapies targeting muscle, gut microbiota, or autophagy present additional avenues for immunomodulation in sarcopenia. This narrative review explores the immunological underpinnings of sarcopenia, elucidating the relationship between the immune system and muscle during ageing. Additionally, the review discusses new areas such as the gut-muscle axis and autophagy, which bridge immune system function and muscle health. Insights into current and potential approaches for sarcopenia management through modulation of the immune system are provided, along with suggestions for future research directions and therapeutic strategies. We aim to guide further investigation into clinical immunological biomarkers and identify indicators for sarcopenia diagnosis and potential treatment targets to combat this condition. We also aim to draw attention to the importance of considering immunomodulation in the clinical management of sarcopenia.

A novel treatment strategy targeting cellular pathways with natural products to alleviate sarcopenia

Sarcopenia is a condition marked by a significant reduction in muscle mass and strength, primarily due to the aging process, which critically impacts muscle protein dynamics, metabolic functions, and overall physical functionality. This condition leads to increased body fat and reduced daily activity, contributing to severe health issues and a lower quality of life among the elderly. Recognized in the ICD-10-CM only in 2016, sarcopenia lacks definitive treatment options despite its growing prevalence and substantial social and economic implications. Given the aging global population, addressing sarcopenia has become increasingly relevant and necessary. The primary causes include aging, cachexia, diabetes, and nutritional deficiencies, leading to imbalances in protein synthesis and degradation, mitochondrial dysfunction, and hormonal changes. Exercise remains the most effective intervention, but it is often impractical for individuals with limited mobility, and pharmacological options such as anabolic steroids and myostatin inhibitors are not FDA-approved and are still under investigation. This review is crucial as it examines the potential of natural products as a novel treatment strategy for sarcopenia, targeting multiple mechanisms involved in its pathogenesis. By exploring natural products' multi-targeted effects, this study aims to provide innovative and practical solutions for sarcopenia management. Therefore, this review indicates significant improvements in muscle mass and function with the use of specific natural compounds, suggesting promising alternatives for those unable to engage in regular physical activity.

Nicotinamide N-methyltransferase inhibition mimics and boosts exercise-mediated improvements in muscle function in aged mice

Human hallmarks of sarcopenia include muscle weakness and a blunted response to exercise. Nicotinamide N-methyltransferase inhibitors (NNMTis) increase strength and promote the regenerative capacity of aged muscle, thus offering a promising treatment for sarcopenia. Since human hallmarks of sarcopenia are recapitulated in aged (24-month-old) mice, we treated mice from 22 to 24 months of age with NNMTi, intensive exercise, or a combination of both, and compared skeletal muscle adaptations, including grip strength, longitudinal running capacity, plantarflexor peak torque, fatigue, and muscle mass, fiber type, cross-sectional area, and intramyocellular lipid (IMCL) content. Exhaustive proteome and metabolome analyses were completed to identify the molecular mechanisms underlying the measured changes in skeletal muscle pathophysiology. Remarkably, NNMTi-treated aged sedentary mice showed ~ 40% greater grip strength than sedentary controls, while aged exercised mice only showed a 20% increase relative to controls. Importantly, the grip strength improvements resulting from NNMTi treatment and exercise were additive, with NNMTi-treated exercised mice developing a 60% increase in grip strength relative to sedentary controls. NNMTi treatment also promoted quantifiable improvements in IMCL content and, in combination with exercise, significantly increased gastrocnemius fiber CSA. Detailed skeletal muscle proteome and metabolome analyses revealed unique molecular mechanisms associated with NNMTi treatment and distinct molecular mechanisms and cellular processes arising from a combination of NNMTi and exercise relative to those given a single intervention. These studies suggest that NNMTi-based drugs, either alone or combined with exercise, will be beneficial in treating sarcopenia and a wide range of age-related myopathies.

The Feasibilty of the Motor Control Home Ergonomics Elderlies' Prevention of Falls (McHeELP) Programme in Patients with Sarcopenia: A Pilot Study

Objectives

The objective of this pilot study was to investigate the feasibility of a three month 'Motor control Home ergonomics Elderlies' Prevention of falls' (McHeELP) programme on muscle mass, muscle strength, functionality, balance and fear of falling among older adults with sarcopenia.

Methods

A feasibility study of the McHeELP programme was performed in patients with sarcopenia. Primary outcome measures included number of participants; number of participants that showed engagement with the programme; adherence rates; data loss in questionnaires and secondary outcome measures; any adverse events, related or not to the intervention programme. All participants received a home-based motor control exercise programme combined with an ergonomic home modification for 12 weeks. Secondary outcome measures included Hand Grip Strength, Bioimpendance Analysis, Muscle Mass, Functionality and Fear of Falling.

Results

Twelve participants, (74.9±5 years), completed the pilot study. Significant differences were recorded before and after the programme on participants' functionality (p < 0.001), balance (p < 0.05) and fear of falling (p < 0.001).

Conclusions

The present study revealed that the McHeELP programme is fesasible and that it is possible to implement the programme in clinical practice. The McHeELP programme positively affects functionality, balance and fear of falling. Thus, it seems feasible to conduct a full-scale randomised controlled trial.

Extruded alginate tubes with myogenic potential

BACKGROUND

There are currently no proven methods to reverse muscle loss in humans, which is caused by trauma (e.g., volumetric muscle loss, VML), genetic neuromuscular diseases (e.g., muscular dystrophies, MDs), and accelerated senescence (e.g., sarcopenia). Since muscle tissue is capable of regeneration through muscle satellite cells (MuSCs), the implantation of autologous (or other) donor MuSCs and MuSC-derived myoblasts into host muscles can promote donor-cell-derived myogenesis. Direct injection or implantation of MuSCs or MuSC-derived myoblasts into host muscles only promotes minimal donor-cell-derived myogenesis, whereas implantation of MuSCs/myoblasts along with associated muscle tissue (muscle fibers, extracellular matrix, neurovascular pathways, etc.) gives better results.

METHODS

We aim to leverage the benefits of constraining donor myogenic cells within a template that resembles muscle tissue. In this paper, we present a workflow for basic and translational studies aimed at promoting donor-cell-derived myogenesis to increase functional muscle mass in mice. Our workflow involves preparing a slurry of 10% sodium alginate mixed with myogenic cells in cell culture media, extruding the cell-containing slurry into 10% calcium lactate to form tubes, and implanting the cellularized alginate tubes into host muscle.

RESULTS

Our data suggest that, the extruded alginate tubes can tolerate a peak stress of 1892 ± 527 mN, that the elastic range is at ~75-125% strain beyond initial length, and that the Young's modulus (stiffness) is 14.17 ± 1.68 %/mm2. Importantly, these mechanical properties render the alginate tubes suitable for a published technique known as minimally-invasive muscle embedding (MIME) that was developed by us to implant myogenic material into host muscle. MIME involves threading donor myogenic tissue into a needle track created within a host muscle. Cellularized alginate tubes implanted into the tibialis anterior muscle of previously euthanized mice had numerous hematoxylin-stained structures similar to nuclear staining, supporting the idea that our alginate tubes can support cell seeding. Alginate tubes that were seeded with MuSCs, incubated in MuSC/myoblast growth (i.e., proliferation) media for two days, incubated in myotube differentiation media for six days, and then minced and reseeded in new dishes, were able to promote in vitro myoblast outgrowth over several days.

DISCUSSION

This pilot study is limited in its translational scope because it was performed in vitro and with previously euthanized mice. Additional studies are needed to confirm that cellularized alginate tubes can promote the de novo development of donor-cell-derived muscle fibers, which can contribute to contractile force production.

CONCLUSION

Alginate tubes with MuSC/myoblasts can be generated by a simple extrusion method. The alginate tubes have sufficient mechanical strength to tolerate insertion into a host muscle, in a minimally-invasive manner, through a needle track. The cellularized alginate tubes demonstrate myogenic potential since they are capable of being maintained in culture conditions for several days, after which they can still facilitate myoblast outgrowth in a dish.

Associations between life's essential 8 and sarcopenia in US adults: a cross-sectional analysis

Cardiovascular disease (CVD) is closely associated with sarcopenia. We aimed to examine the relationship between Life's Essential 8 (LE8) and the incidence of sarcopenia among adults in the United States. In this study, a cross-sectional analysis was conducted using data from the National Health and Nutrition Examination Survey from 2013 to 2018 and included 5999 adult participants. LE8 score was categorized into low (< 49), moderate (49-79), and high CVH (≥ 79) groups and consisted of health behavior score and health factor score based on American Heart Association definitions. Sarcopenia was defined according to The Foundation for the National Institutes of Health Sarcopenia Project. Multivariate logistic regressions, restricted cubic spline regressions, and subgroup analyses were used to assess the association between LE8 and sarcopenia. LE8 and its subscales score were negatively associated with the incidence of sarcopenia in US adults.

Sarcopenia and its effects on outcome of lumbar spine surgeries

PURPOSE

Sarcopenia, defined as progressive impairment of muscle function secondary to loss of skeletal muscle mass, has prevalence of 24-56% in patients > 60 years. Forty-four per cent of elderly patients undergoing orthopaedic surgery are found to be sarcopenic. It is a known risk factor for fall, fractures, disability, increased post-operative morbidity and mortality. If diagnosed pre-operatively, it can help prepare the patient and surgical team to foresee complications and thereby reduce morbidity and mortality. In the present study, we evaluated and correlated sarcopenia with the surgical outcome of operated patients with lumbar spine pathology.

MATERIALS AND METHODS

A prospective, observational study was conducted on 114 patients > 40 years undergoing lumbar spine surgeries, who were studied and followed up for 3 months. They were segregated into 5 groups based on age (40-50 year, 50-60 year, 60-70 year, 70-80 year, and  > 80 year) and were assessed separately. Data on demography, grip strength analysis, 30-s chair stand test, Psoas muscle index (calculated on pre-operative MRI), pre- and post-operative ODI (Oswestry Disability Index) scores at 2 weeks and 3 months, Dindo-Clavien Classification of peri-operative complications, 90-day readmission rates and mortality (if any) were included. Patients were segregated into sarcopenic and non-sarcopenic groups based on the definition and set parameters as per the European Working Group on Sarcopenia in Older People (EWGSOP). A comparative analysis between these groups was performed.

RESULTS

Of 114 patients, there were 18 patients in 40-49 years, 24 in 50-59 years, 33 in 60-69 years, 30 in 70-79 years and 9 in > 80 years age group. Statistically significant difference in peri-operative ODI scores was seen in sarcopenic vs non-sarcopenic patients in all age groups (p < 0.05) except 40-49 years. The results showed that sarcopenic group had higher rate of peri-operative complications, delayed mobilisation, longer stay and mortality compared to non-sarcopenic group.

CONCLUSION

We conclude that sarcopenic patients have poor outcome in lumbar spine surgery compared to those without. So, by diagnosing sarcopenia using tests routinely done as pre-operative requirement, one can reduce radiation exposure and cost of treatment. The management can be revolutionised by predicting those who are at high risk of developing post-operative complications and poor surgical outcomes by mere diagnosis of sarcopenia. This knowledge will benefit both the patients and the surgeons.

Temporal Muscle Thickness: A Practical Approximation for Assessing Muscle Mass in Older Adults

OBJECTIVE

Ongoing research has evidenced the importance of muscle measurement in predicting adverse outcomes. Measurement of other muscles is promising in current research. This study aimed to determine the correlation between temporal muscle thickness (TMT) and appendicular lean soft tissue (ALSTI) in older adults.

DESIGN

Cross-sectional study.

SETTINGS AND PARTICIPANTS

Single cohort gathered in Gothenburg, Sweden, consisting of individuals born in 1944 (n = 1203).

METHODS

We studied 657 magnetic resonance images to measure TMT. Comparisons of TMT with dual-energy X-ray absorptiometry ALSTI (kg/m2) as a reference standard were performed. Finally, TMT associations with cognition evaluated using the Mini-Mental State Examination (MMSE), gait speed, and handgrip strength were explored with linear regressions.

RESULTS

The correlation between TMT and ALSTI was weak yet significant (r = 0.277, P < .001). TMT exhibited significant associations with MMSE (estimate = 0.168, P = .002), gait speed (estimate = 1.795, P < .001), and ALSTI (estimate = 0.508, P < .001). These associations varied when analyzed by sex. In women, TMT was significantly associated with gait speed (estimate = 1.857, P = .005) and MMSE (estimate = 0.223, P = .003). In men, TMT scores were significantly correlated with ALSTI scores (estimate = 0.571, P < .001).

CONCLUSION AND IMPLICATIONS

Repurposing head images can be an accessible alternative to detect muscle mass and ultimately detect sarcopenia. These studies have the potential to trigger interventions or further evaluation to improve the muscle and overall health of individuals. However, additional research is warranted before translating these findings into clinical practice.

A Combination Study of Pre- and Clinical Trial: Seaweed Consumption Reduces Aging-Associated Muscle Loss!

Seaweed consumption in Asian food cultures may benefit longevity and age-related conditions like sarcopenia with aging. However, sarcopenia lacks a definitive treatment, and pharmaceutical options have limitations in efficacy and safety. Recent studies on aging female mice found that Ishige okamurae (IO), a brown algae, and its active compound diphloroethohydroxycarmalol improved sarcopenia. Further research is needed to understand the effects of seaweed consumption on sarcopenia in humans. This clinical trial divided participants into a test group (receiving 500 mg/kg IO supplementation, mean±SD; age 62.73±7.18 years, n=40) and a control group (age 63.10±7.06 years, n=40). Hazard analysis assessed vital signs and muscle strength improvement during the trial. Additionally, 12-month-old mice were oral-fed IO at different doses (50, 100, 200 mg/kg) for 6-weeks. Aging and muscle-wasting related markers were evaluated, including grip strength, body weight and compositions, serum-parameters, and molecular-changes. The clinical trial found no significant changes in toxicity-parameters between the groups (p<0.05) after 12-weeks of IO supplementation. The IO group exhibited a remarkable increase in lower-limb quadriceps muscle-strength compared to the control (p=0.002). Furthermore, IO treatment improved age-related decline in quadriceps strength in the subgroup; under 61-years-old (p=0.004), without significant differences in foot-dominancy between groups (p=0.171). In 12-month-old male mice, IO administration improved age-related deficiencies in grip strength (p>0.0001) and testosterone (p=0.0001). Muscular regeneration parameters, such as lean-mass (p>0.0001), inhibition of proteolysis (measured by changes in myogenin and atrogin-1 protein expressions), cross-sectional myofiber area (p>0.0001), number of satellite cells (p=0.0001), and increased mitochondrial oxidative phosphorylation complexes in muscle tissue indicative of mitochondrial biogenesis, were also improved by IO administration. This trial is the first to explore the positive association between consuming brown-algae IO and age-related decreases in muscle strength. IO treatment helps maintain muscle mass and delays muscle wasting during aging, suggesting it as a potent nutritional strategy to protect against aging-associated sarcopenia.

Effectiveness of Combined Exercise and Nutrition Interventions in Preventing and Improving Sarcopenia in Frail or Healthy Older Adults: A Systematic Review

The current systematic review compared whether combined exercise and nutrition interventions are effective in preventing or improving sarcopenia in frail older adults and healthy older adults. Medline, Embase, Cochrane Library, and CINAHL were searched for randomized controlled trials. Of the 1,596 citations, 22 trials (N = 1,767) were included in the final sample. In frail older adults, significant improvement after combined exercise and nutrition interventions was observed in seven indicators: skeletal muscle index, 0.16 kg/m2; handgrip, 1.41 kg; knee extension strength, 0.24 Nm; five-repetition chair-stand test, -1.89 sec; gait speed, 0.06 m/s; Short Physical Performance Battery, 0.43; and Timed Up and Go test, -0.56 sec. In healthy older adults, two indicators improved and showed statistically significant differences: handgrip, 2.15 kg; and 6-Minute Walking Test, 9.71 m. Combined exercise and nutritional interventions can improve skeletal muscle quality, strength, and physical performance in frail and healthy older adults. [Research in Gerontological Nursing, 16(6), 312-320.].

Understanding the Consequences of Fatty Bone and Fatty Muscle: How the Osteosarcopenic Adiposity Phenotype Uncovers the Deterioration of Body Composition

Adiposity is central to aging and several chronic diseases. Adiposity encompasses not just the excess adipose tissue but also body fat redistribution, fat infiltration, hypertrophy of adipocytes, and the shifting of mesenchymal stem cell commitment to adipogenesis. Bone marrow adipose tissue expansion, inflammatory adipokines, and adipocyte-derived extracellular vesicles are central to the development of osteopenic adiposity. Adipose tissue infiltration and local adipogenesis within the muscle are critical in developing sarcopenic adiposity and subsequent poorer functional outcomes. Ultimately, osteosarcopenic adiposity syndrome is the result of all the processes noted above: fat infiltration and adipocyte expansion and redistribution within the bone, muscle, and adipose tissues, resulting in bone loss, muscle mass/strength loss, deteriorated adipose tissue, and subsequent functional decline. Increased fat tissue, typically referred to as obesity and expressed by body mass index (the latter often used inadequately), is now occurring in younger age groups, suggesting people will live longer with the negative effects of adiposity. This review discusses the role of adiposity in the deterioration of bone and muscle, as well as adipose tissue itself. It reveals how considering and including adiposity in the definition and diagnosis of osteopenic adiposity, sarcopenic adiposity, and osteosarcopenic adiposity will help in better understanding the pathophysiology of each and accelerate possible therapies and prevention approaches for both relatively healthy individuals or those with chronic disease.

Mitochondria Transplantation from Stem Cells for Mitigating Sarcopenia

Sarcopenia is defined as the age-related loss of muscle mass and function that can lead to prolonged hospital stays and decreased independence. It is a significant health and financial burden for individuals, families, and society as a whole. The accumulation of damaged mitochondria in skeletal muscle contributes to the degeneration of muscles with age. Currently, the treatment of sarcopenia is limited to improving nutrition and physical activity. Studying effective methods to alleviate and treat sarcopenia to improve the quality of life and lifespan of older people is a growing area of interest in geriatric medicine. Therapies targeting mitochondria and restoring mitochondrial function are promising treatment strategies. This article provides an overview of stem cell transplantation for sarcopenia, including the mitochondrial delivery pathway and the protective role of stem cells. It also highlights recent advances in preclinical and clinical research on sarcopenia and presents a new treatment method involving stem cell-derived mitochondrial transplantation, outlining its advantages and challenges.

Chemokine/ITGA4 Interaction Directs iPSC-Derived Myogenic Progenitor Migration to Injury Sites in Aging Muscle for Regeneration

The failure of muscle to repair after injury during aging may be a major contributor to muscle mass loss. We recently generated muscle progenitor cells (MPCs) from human-induced pluripotent stem-cell (iPSC) cell lines using small molecules, CHIR99021 and Givinostat (Givi-MPCs) sequentially. Here, we test whether the chemokines overexpressed in injured endothelial cells direct MPC migration to the site by binding to their receptor, ITGA4. ITGA4 was heavily expressed in Givi-MPCs. To study the effects on the mobilization of Givi-MPCs, ITGA4 was knocked down by an ITGA4 shRNA lentiviral vector. With and without ITGA4 knocked down, cell migration in vitro and cell mobilization in vivo using aged NOD scid gamma (NSG) mice and mdx/scid mice were analyzed. The migration of shITGA4-Givi-MPCs was significantly impaired, as shown in a wound-healing assay. The knockdown of ITGA4 impaired the migration of Givi-MPCs towards human aortic endothelial cells (HAECs), in which CX3CL1 and VCAM-1 were up-regulated by the treatment of TNF-α compared with scramble ones using a transwell system. MPCs expressing ITGA4 sensed chemokines secreted by endothelial cells at the injury site as a chemoattracting signal to migrate to the injured muscle. The mobilization of Givi-MPCs was mediated by the ligand-receptor interaction, which facilitated their engraftment for repairing the sarcopenic muscle with injury.

Diagnostics of inflammaging in relation to sarcopenia

One of the theories about aging focuses on the immune response and relates to the activation of subclinical and chronic inflammation. This study was designed to investigate the relationship between inflammation and sarcopenia and to evaluate the influence of lifestyle on the inflammatory profile. Finally, therapeutic strategies to counteract the pathophysiological effect of skeletal muscle aging were also indicated. One hundred seventy-three individuals aged 71.5 ± 6.8 years were divided into two groups: sarcopenia and probable sarcopenia (n = 39) and no sarcopenia (n = 134). Sarcopenia was assessed according to the algorithm of the European Working Group on Sarcopenia in the older adults 2. C-reactive protein (CRP) (p = 0.011) and CRP/albumin ratio (p = 0.030) as well as IL-1β (p = 0.002), cfDNA (p < 0.001) and bilirubin levels (p = 0.002) were significantly higher in the sarcopenia group as opposed to the no sarcopenia group. No significant differences were observed between groups in the concentration of TNFα (p = 0.429) and IL-6 (p = 0.300). An inverse correlation was found between gait speed and cfDNA (r_s = -0.234, p < 0.01) and IL-1β (r_s = -0.263, p < 0.01). The ROC analysis of cfDNA, CRP, IL-1β and bilirubin ranged from 0.6 to 0.7, which confirms the association between sarcopenia and inflammatory mediators and indicates high clinical usefulness of cfDNA and bilirubin in sarcopenia prediction. We also indicated a link between inflammation and fitness level in the older adult thereby providing evidence that lifestyle exercise should be a key therapeutic strategy in sarcopenia prevention.

Cell-Based Therapies for Degenerative Musculoskeletal Diseases

Degenerative musculoskeletal diseases (DMDs), including osteoporosis, osteoarthritis, degenerative disc disease, and sarcopenia, present major challenges in the aging population. Patients with DMDs present with pain, functional decline, and reduced exercise tolerance, which result in long-term or permanent deficits in their ability to perform daily activities. Current strategies for dealing with this cluster of diseases focus on relieving pain, but they have a limited capacity to repair function or regenerate tissue. Cell-based therapies have attracted considerable attention in recent years owing to their unique mechanisms of action and remarkable effects on regeneration. In this review, current experimental attempts to use cell-based therapies for DMDs are highlighted, and the modes of action of different cell types and their derivatives, such as exosomes, are generalized. In addition, the latest findings from state-of-the-art clinical trials are reviewed, approaches to improve the efficiency of cell-based therapies are summarized, and unresolved questions and potential future research directions for the translation of cell-based therapies are identified.

Polyamines and Physical Activity in Musculoskeletal Diseases: A Potential Therapeutic Challenge

Autophagy dysregulation is commonplace in the pathogenesis of several invalidating diseases, such as musculoskeletal diseases. Polyamines, as spermidine and spermine, are small aliphatic cations essential for cell growth and differentiation, with multiple antioxidant, anti-inflammatory, and anti-apoptotic effects. Remarkably, they are emerging as natural autophagy regulators with strong anti-aging effects. Polyamine levels were significantly altered in the skeletal muscles of aged animals. Therefore, supplementation of spermine and spermidine may be important to prevent or treat muscle atrophy. Recent in vitro and in vivo experimental studies indicate that spermidine reverses dysfunctional autophagy and stimulates mitophagy in muscles and heart, preventing senescence. Physical exercise, as polyamines, regulates skeletal muscle mass inducing proper autophagy and mitophagy. This narrative review focuses on the latest evidence regarding the efficacy of polyamines and exercise as autophagy inducers, alone or coupled, in alleviating sarcopenia and aging-dependent musculoskeletal diseases. A comprehensive description of overall autophagic steps in muscle, polyamine metabolic pathways, and effects of the role of autophagy inducers played by both polyamines and exercise has been presented. Although literature shows few data in regard to this controversial topic, interesting effects on muscle atrophy in murine models have emerged when the two "autophagy-inducers" were combined. We hope these findings, with caution, can encourage researchers to continue investigating in this direction. In particular, if these novel insights could be confirmed in further in vivo and clinical studies, and the two synergic treatments could be optimized in terms of dose and duration, then polyamine supplementation and physical exercise might have a clinical potential in sarcopenia, and more importantly, implications for a healthy lifestyle in the elderly population.

Longitudinal transcriptomic analysis of mouse sciatic nerve reveals pathways associated with age-related muscle pathology

BACKGROUND

Sarcopenia, the age-associated decline in skeletal muscle mass and strength, has long been considered a disease of muscle only, but accumulating evidence suggests that sarcopenia could originate from the neural components controlling muscles. To identify early molecular changes in nerves that may drive sarcopenia initiation, we performed a longitudinal transcriptomic analysis of the sciatic nerve, which governs lower limb muscles, in aging mice.

METHODS

Sciatic nerve and gastrocnemius muscle were obtained from female C57BL/6JN mice aged 5, 18, 21 and 24 months old (n = 6 per age group). Sciatic nerve RNA was extracted and underwent RNA sequencing (RNA-seq). Differentially expressed genes (DEGs) were validated using quantitative reverse transcription PCR (qRT-PCR). Functional enrichment analysis of clusters of genes associated with patterns of gene expression across age groups (adjusted P-value < 0.05, likelihood ratio test [LRT]) was performed. Pathological skeletal muscle aging was confirmed between 21 and 24 months by a combination of molecular and pathological biomarkers. Myofiber denervation was confirmed with qRT-PCR of Chrnd, Chrng, Myog, Runx1 and Gadd45ɑ in gastrocnemius muscle. Changes in muscle mass, cross-sectional myofiber size and percentage of fibres with centralized nuclei were analysed in a separate cohort of mice from the same colony (n = 4-6 per age group).

RESULTS

We detected 51 significant DEGs in sciatic nerve of 18-month-old mice compared with 5-month-old mice (absolute value of fold change > 2; false discovery rate [FDR] < 0.05). Up-regulated DEGs included Dbp (log2 fold change [LFC] = 2.63, FDR < 0.001) and Lmod2 (LFC = 7.52, FDR = 0.001). Down-regulated DEGs included Cdh6 (LFC = -21.38, FDR < 0.001) and Gbp1 (LFC = -21.78, FDR < 0.001). We validated RNA-seq findings with qRT-PCR of various up- and down-regulated genes including Dbp and Cdh6. Up-regulated genes (FDR < 0.1) were associated with the AMP-activated protein kinase signalling pathway (FDR = 0.02) and circadian rhythm (FDR = 0.02), whereas down-regulated DEGs were associated with biosynthesis and metabolic pathways (FDR < 0.05). We identified seven significant clusters of genes (FDR < 0.05, LRT) with similar expression patterns across groups. Functional enrichment analysis of these clusters revealed biological processes that may be implicated in age-related changes in skeletal muscles and/or sarcopenia initiation including extracellular matrix organization and an immune response (FDR < 0.05).

CONCLUSIONS

Gene expression changes in mouse peripheral nerve were detected prior to disturbances in myofiber innervation and sarcopenia onset. These early molecular changes we report shed a new light on biological processes that may be implicated in sarcopenia initiation and pathogenesis. Future studies are warranted to confirm the disease modifying and/or biomarker potential of the key changes we report here.

Mitochondrial transplantation as a possible therapeutic option for sarcopenia

With advancing age, the skeletal muscle phenotype is characterized by a progressive loss of mass, strength, and quality. This phenomenon, known as sarcopenia, has a negative impact on quality of life and increases the risk of morbidity and mortality in older adults. Accumulating evidence suggests that damaged and dysfunctional mitochondria play a critical role in the pathogenesis of sarcopenia. Lifestyle modifications, such as physical activity, exercise, and nutrition, as well as medical interventions with therapeutic agents, are effective in the management of sarcopenia and offer solutions to maintain and improve skeletal muscle health. Although a great deal of effort has been devoted to the identification of the best treatment option, these strategies are not sufficient to overcome sarcopenia. Recently, it has been reported that mitochondrial transplantation may be a possible therapeutic approach for the treatment of mitochondria-related pathological conditions such as ischemia, liver toxicity, kidney injury, cancer, and non-alcoholic fatty liver disease. Given the role of mitochondria in the function and metabolism of skeletal muscle, mitochondrial transplantation may be a possible option for the treatment of sarcopenia. In this review, we summarize the definition and characteristics of sarcopenia and molecular mechanisms associated with mitochondria that are known to contribute to sarcopenia. We also discuss mitochondrial transplantation as a possible option. Despite the progress made in the field of mitochondrial transplantation, further studies are needed to elucidate the role of mitochondrial transplantation in sarcopenia. KEY MESSAGES: Sarcopenia is the progressive loss of skeletal muscle mass, strength, and quality. Although the specific mechanisms that lead to sarcopenia are not fully understood, mitochondria have been identified as a key factor in the development of sarcopenia. Damaged and dysfunctional mitochondria initiate various cellular mediators and signaling pathways, which largely contribute to the age-related loss of skeletal muscle mass and strength. Mitochondrial transplantation has been reported to be a possible option for the treatment/prevention of several diseases. Mitochondrial transplantation may be a possible therapeutic option for improving skeletal muscle health and treating sarcopenia. Mitochondrial transplantation as a possible treatment option for sarcopenia.

Fatty acid amides as potential circulating biomarkers for sarcopenia

BACKGROUND

Sarcopenia is characterized by a progressive decrease in skeletal muscle mass and function with age. Given that sarcopenia is associated with various metabolic disorders, effective metabolic biomarkers for its early detection are required. We aimed to investigate the metabolic biomarkers related to sarcopenia in elderly men and perform experimental studies using metabolomics.

METHODS

Plasma metabolites from 142 elderly men, comprising a sarcopenia group and an age-matched control group, were measured using global metabolome profiling. Muscle and plasma samples from an aging mouse model of sarcopenia, as well as cell media and cell lysates during myoblast differentiation, were analysed based on targeted metabolome profiling. Based on these experimental results, fatty acid amides were quantified from human plasma as well as human muscle tissues. The association of fatty acid amide levels with sarcopenia parameters was evaluated.

RESULTS

Global metabolome profiling showed that fatty acid amide levels were significantly different in the plasma of elderly men with sarcopenia (all Ps < 0.01). Consistent with these results in human plasma, targeted metabolome profiling in an aging mouse model of sarcopenia showed decreased levels of fatty acid amides in plasma but not in muscle tissue. In addition, the levels of fatty acid amides increased in cell lysates during muscle cell differentiation. Targeted metabolome profiling in men showed decreased docosahexaenoic acid ethanolamide (DHA EA) levels in the plasma (P = 0.016) but not in the muscle of men with sarcopenia. DHA EA level was positively correlated with sarcopenia parameters such as skeletal muscle mass index (SMI) and handgrip strength (HGS) (P = 0.001, P = 0.001, respectively). The area under the receiver-operating characteristic curve (AUC) for DHA EA level ≤ 4.60 fmol/μL for sarcopenia was 0.618 (95% confidence interval [CI]: 0.532-0.698). DHA EA level ≤ 4.60 fmol/μL was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR]: 2.11, 95% CI: 1.03-4.30), independent of HGS. The addition of DHA EA level to age and HGS significantly improved the AUC from 0.620 to 0.691 (P = 0.0497).

CONCLUSIONS

Our study demonstrated that fatty acid amides are potential circulating biomarkers in elderly men with sarcopenia. DHA EA, in particular, strongly related to muscle mass and strength, can be a key metabolite to become a reliable metabolic biomarker for sarcopenia. Further research on fatty acid amides will provide insights into the metabolomic changes relevant to sarcopenia from an aging perspective.

Sarcopenia Predicts Inferior Progression-Free Survival in Lymphoma Patients Treated with Autologous Hematopoietic Stem Cell Transplantation

Autologous hematopoietic stem cell transplantation (ASCT) improves survival for patients with chemotherapy-sensitive lymphoma. Validated scoring systems are used in the clinical setting to predict treatment toxicity and survival; however, complications related to disease and treatment still occur, highlighting challenges in optimal patient selection and the need for novel predictors. Analysis of body composition and muscle mass can provide an objective assessment to identify vulnerable populations, as sarcopenia and frailty have been reported to predict outcomes in other tumor types. In this retrospective cohort study of patients undergoing ASCT for lymphoma, we investigated associations of sarcopenia with clinically significant outcomes, including overall survival (OS) and progression-free survival (PFS). Computed tomography (CT) images of 78 patients obtained routinely pretransplantation were used to assess skeletal muscle mass and are reported as skeletal muscle index (SMI). OS, PFS, and clinical outcomes of interest were compared between groups. Twenty-seven patients (34.6%) in the cohort met the criteria for sarcopenia. Patients with sarcopenia had a significantly shorter 3-year PFS (59% [95% confidence interval (CI), 38% to 75%] versus 84% [95% CI, 71% to 92%]; P = .02) after 3 years of follow up, whereas there was no difference in OS between patients with and those without sarcopenia (78% [95% CI, 57% to 89%] versus 88% [95% CI, 76% to 95%]; P = .25). Interestingly, no difference in survival was found with stratification based on the Karnofsky Performance Scale or Hematopoietic Cell Transplantation-Specific Comorbidity Index. There also were no significant between-group differences in length of hospital stay and the incidences of other clinical outcomes of interest, including febrile neutropenia, mucositis, total parenteral nutrition requirement, acute kidney injury, rate of readmission, or intensive care unit admission. This is the first study to our knowledge to correlate sarcopenia with disease control and PFS after ASCT in lymphoma. Possible explanations include a higher rate of chemotherapy-related toxicity, leading to disruptions of treatment as well as dysfunction of antitumor immunity secondary to impaired regulations from myokines from the loss of muscle mass or an unknown cause that is yet to be elucidated. Physical therapy programs and personalized regimens for treatment based on the analysis of body composition indices can be further studied and implemented to mitigate treatment-related toxicity and to optimize survival in patients with sarcopenia.

Sarcopenia Is Associated with an Increased Risk of Postoperative Complications Following Total Hip Arthroplasty for Osteoarthritis

Sarcopenia is a state of catabolic muscle wasting prevalent in geriatric patients. Likewise, osteoarthritis is an age-related musculoskeletal disease affecting patients with similar demographics. Late-stage hip osteoarthritis is often treated with total hip arthroplasty (THA). As sarcopenia influences the surgical outcomes, this study aimed to assess the impact of sarcopenia on the outcomes of THA. A 1:3 matched case-control study of sarcopenic to control patients was performed using a large national database. In total, 3992 patients were analyzed. Sarcopenic patients undergoing THA were more likely to experience dislocation (odds ratio (OR) = 2.19, 95% confidence interval (CI) 1.21-3.91) within 1 year of THA. Furthermore, sarcopenic patients had higher urinary tract infection rates (OR = 1.79, CI 1.32-2.42) and a greater risk of 90-day hospital readmission (hazard ratio (HR) = 1.39, CI 1.10-1.77). Sarcopenic patients experienced more falls (OR = 1.62, CI 1.10-2.39) and fragility fractures (OR = 1.77, CI 1.34-2.31). Similarly, sarcopenic patients had higher day of surgery costs (USD 13,534 vs. USD 10,504) and 90-day costs (USD 17,139 vs. USD 13,394) compared with the controls. Ultimately, sarcopenic patients undergoing THA experience higher rates of postoperative complications and incur greater medical costs. Given the potential risks, orthopedic surgeons may consider treating or reducing the severity of sarcopenia before surgery.

From Sarcopenia to Depressive Symptoms in Elderly: A Path Analysis

BACKGROUND

Sarcopenia is an age-related progressive, generalized skeletal muscle disorder involving the accelerated loss of muscle function and muscle mass. The aim of this study was to assess the complex relationship between sarcopenia, malnutrition, cognitive impairment, physical activity, and depression in the elderly, with the potential role of quality of life as a mediator in these associations.

METHODS

A cross-sectional study was conducted on a sample (n = 298) of elderly patients admitted to Special Hospital for Rehabilitation "Termal", Vrdnik, Serbia. Sarcopenia, the risk for malnutrition, cognitive impairment, physical activity, quality of life, and depressive symptoms were measured by standardized instruments. Additional data included sociodemographic characteristics. Simultaneous assessment of the direct and indirect relationships of all determinants was performed by path analysis.

RESULTS

A total of 40% (n = 120) of the elderly were diagnosed with sarcopenia, and 42.6% had depression symptoms. The risk of malnutrition was present in 23.5%, cognitive impairment in 5.4%, and a low level of physical activity was reported in 26.2% of elderly participants. The mean reported quality of life measured by Sarcopenia and Quality of Life Questionnaire was 60 (on the scale ranging from 0 to 100; where a higher score reflects a higher quality of life). The best-fitted model (χ2/DF = 1.885, NFI = 0.987, CFI = 0.993, GFI = 0.997, RMSEA = 0.055) highlighted the mediating effect of quality of life between sarcopenia, malnutrition, cognitive impairment, lower level of physical activities and depression. According to the model, quality of life was a direct negative predictor of depressive symptoms in the elderly, while malnutrition positively affected depression.

CONCLUSIONS

The presented path model may assist rehabilitation centers in developing strategies to screen for sarcopenia and risk of malnutrition, and promote physical activity in elderly, aiming to prevent their negative effects on mental health. For the elderly currently affected by sarcopenia, we consider regenerative medicine and stem cell therapy, which, in view of their etiology, could be a potential therapeutic strategy for sarcopenia.

Sarcopenia and Postoperative Complications, Cost of Care, and All-Cause Hospital Readmission Following Lumbar Spine Arthrodesis: A Propensity Matched Cohort Study

OBJECTIVE

Sarcopenia, characterized by decreased muscle mass and function, is projected to affect more than 200 million people worldwide by 2060. This study aimed to evaluate the rates of short-term complications following lumbar spine arthrodesis in patients with and without a recent diagnosis of sarcopenia.

METHODS

The PearlDiver database was queried to evaluate all patients who underwent index lumbar spine arthrodesis from 2012 to 2019. Multivariate logistic regression was used to compare rates of 90-day surgical and medical complications. Kaplan-Meier analysis was performed to compare cumulative rates of reoperation and all-cause hospital readmission. Two sample t testing was used to compare costs of care. Statistical significance was set at P < 0.05 a priori.

RESULTS

Of 239,953 patients undergoing lumbar spine arthrodesis, 1087 had a recent diagnosis of sarcopenia (0.45%) before surgery. Patients with sarcopenia were significantly more likely to experience a urinary tract infection (odds ratio = 1.41, P = 0.035) and undergo incision and drainage (odds ratio = 2.66, P = 0.010) within 90 days after lumbar arthrodesis. Patients with sarcopeniawere at a 24% greater risk of 1-year all-cause hospital readmission. The 90-day cost of care was significantly greater in patients with sarcopenia ($37,689.86 vs. $26,635.72; P < 0.001).

CONCLUSIONS

In patients undergoing lumbar spine arthrodesis, sarcopenia is associated with an increased risk of postoperative complications, including increased costs of care. Spine surgeons should consider screening patients for sarcopenia preoperatively and counsel them regarding their increased risk of complications. Additionally, surgeons may consider preoperative optimization, like the management of low bone density.

TGF-β1-supplemented decellularized annulus fibrosus matrix hydrogels promote annulus fibrosus repair

Annulus fibrosus (AF) repair remains a challenge because of its limited self-healing ability. Endogenous repair strategies combining scaffolds and growth factors show great promise in AF repair. Although the unique and beneficial characteristics of decellularized extracellular matrix (ECM) in tissue repair have been demonstrated, the poor mechanical property of ECM hydrogels largely hinders their applications in tissue regeneration. In the present study, we combined polyethylene glycol diacrylate (PEGDA) and decellularized annulus fibrosus matrix (DAFM) to develop an injectable, photocurable hydrogel for AF repair. We found that the addition of PEGDA markedly improved the mechanical strength of DAFM hydrogels while maintaining their porous structure. Transforming growth factor-β1 (TGF-β1) was further incorporated into PEGDA/DAFM hydrogels, and it could be continuously released from the hydrogel. The in vitro experiments showed that TGF-β1 facilitated the migration of AF cells. Furthermore, PEGDA/DAFM/TGF-β1 hydrogels supported the adhesion, proliferation, and increased ECM production of AF cells. In vivo repair performance of the hydrogels was assessed using a rat AF defect model. The results showed that the implantation of PEGDA/DAFM/TGF-β1 hydrogels effectively sealed the AF defect, prevented nucleus pulposus atrophy, retained disc height, and partially restored the biomechanical properties of disc. In addition, the implanted hydrogel was infiltrated by cells resembling AF cells and well integrated with adjacent AF tissue. In summary, findings from this study indicate that TGF-β1-supplemented DAFM hydrogels hold promise for AF repair.

Exercise and mitochondrial mechanisms in patients with sarcopenia

Sarcopenia is a severe loss of muscle mass and functional decline during aging that can lead to reduced quality of life, limited patient independence, and increased risk of falls. The causes of sarcopenia include inactivity, oxidant production, reduction of antioxidant defense, disruption of mitochondrial activity, disruption of mitophagy, and change in mitochondrial biogenesis. There is evidence that mitochondrial dysfunction is an important cause of sarcopenia. Oxidative stress and reduction of antioxidant defenses in mitochondria form a vicious cycle that leads to the intensification of mitochondrial separation, suppression of mitochondrial fusion/fission, inhibition of electron transport chain, reduction of ATP production, an increase of mitochondrial DNA damage, and mitochondrial biogenesis disorder. On the other hand, exercise adds to the healthy mitochondrial network by increasing markers of mitochondrial fusion and fission, and transforms defective mitochondria into efficient mitochondria. Sarcopenia also leads to a decrease in mitochondrial dynamics, mitophagy markers, and mitochondrial network efficiency by increasing the level of ROS and apoptosis. In contrast, exercise increases mitochondrial biogenesis by activating genes affected by PGC1-ɑ (such as CaMK, AMPK, MAPKs) and altering cellular calcium, ATP-AMP ratio, and cellular stress. Activation of PGC1-ɑ also regulates transcription factors (such as TFAM, MEFs, and NRFs) and leads to the formation of new mitochondrial networks. Hence, moderate-intensity exercise can be used as a non-invasive treatment for sarcopenia by activating pathways that regulate the mitochondrial network in skeletal muscle.

A Phytomolecule Icariin Protects from Sarcopenia Partially by Suppressing Myosin Heavy Chain Degradation in Orchiectomized Rats

Treatments are lacking for sarcopenia, which is an age-related disease characterized by loss of skeletal muscle mass, strength, and/or physical performance. Icariin is a phytomolecule from herbal Epimedium, a traditional Chinese medicine widely used to treat musculoskeletal disorders for thousands of years. Here the effects of icariin against sarcopenia are investigated and the underlying mechanism is elucidated. A classic rat model of bilaterally orchiectomized (ORX) is used to induce sarcopenia. After administration for 8 weeks, compared to the control group, the forelimb grip strength, the specific tetanic forces of the soleus (SOL) and extensor digitorum longus muscle (EDL) are higher, and the fiber cross-sectional areas (CSAs) of the gastrocnemius and tibialis anterior muscle are larger in the icariin group. In addition, icariin promotes mRNA and protein expressions of myosin heavy chain (MyHC) both in SOL and EDL. Mechanistically, icariin significantly suppresses the mRNA and protein expressions of FOXO3a, atrogin-1, and MuRF-1, which are related to the degradation of myosin heavy chain. Collectively, icariin protects from sarcopenia in ORX rats characterized by enhancing grip strength and skeletal muscle contraction, as well as increasing skeletal muscle CSA by inhibiting the ubiquitination degradation of the MyHC in skeletal muscle fibers.

The Cytokine Growth Differentiation Factor-15 and Skeletal Muscle Health: Portrait of an Emerging Widely Applicable Disease Biomarker

Growth differentiation factor 15 (GDF-15) is a stress-induced transforming growth factor-β superfamily cytokine with versatile functions in human health. Elevated GDF-15 blood levels associate with multiple pathological conditions, and are currently extensively explored for diagnosis, and as a means to monitor disease progression and evaluate therapeutic responses. This review analyzes GDF-15 in human conditions specifically focusing on its association with muscle manifestations of sarcopenia, mitochondrial myopathy, and autoimmune and viral myositis. The use of GDF-15 as a widely applicable health biomarker to monitor muscle disease is discussed, and its potential as a therapeutic target is explored.

Fetal muscle extract improves muscle function and performance in aged mice

Background: Loss of skeletal muscle mass and function is one of the major musculoskeletal health problems in the aging population. Recent studies have demonstrated differential proteomic profiles at different fetal stages, which might be associated with muscle growth and development. We hypothesized that extract derived from fetal muscle tissues at the stage of hypertrophy could ameliorate the loss of muscle mass and strength in aged mice.

Methods: To allow sufficient raw materials for investigation, skeletal muscle extract from fetal sheep at week 16 of gestation and maternal tissue were used in the present study. iTRAQ (isobaric tags for relative and absolute quantitation) and KEGG pathway analyses identified differentially expressed proteins in fetal sheep muscle extract vs. adult sheep muscle extract. Effects of FSME and ASME on human myoblast proliferation were studied. To examine the effect of FSME in vivo, C57BL/6 male mice at 20 months of age were subjected to intramuscular administration of FSME or vehicle control for 8 weeks. A grip strength test and ex vivo muscle force frequency test were conducted. Finally, serum samples were collected for multiplex analysis to determine potential changes in immunological cytokines upon FSME injection.

Results: Compared with ASME, 697 and 412 peptides were upregulated and downregulated, respectively, in FSME, as indicated by iTRAQ analysis. These peptides were highly related to muscle development, function, and differentiation from GO enrichment analysis. FSME promoted cell proliferation of myoblast cells (+300%, p < 0.01) without causing significant cytotoxicity at the tested concentration range compared with ASME. After 8 weeks of FSME treatment, the percentage of lean mass (+10%, p < 0.05), grip strength (+50%, p < 0.01), and ability in fatigue resistance were significantly higher than those of the control group. Isometric forces stimulated by different frequencies were higher in the control group. Histologically, the control group showed a larger cross-sectional area (+20%, p < 0.01) than the FSME group. The multiplex assay indicated that FSME treatment did not lead to an elevated circulatory level of inflammatory cytokines. Of note, after FSME treatment, we observed a significant drop in the circulating level of IL-12 (p40) from 90.8 ± 48.3 pg/ml to 82.65 ± 4.4 pg/ml, G-CSF from 23476 ± 8341.9 pg/ml to 28.35 ± 24.2 pg/ml, KC from 97.09 ± 21.2 pg/ml to 29.2 ± 7.2 pg/ml, and RANTES from 325.4 ± 17.3 pg/ml to 49.96 ± 32.1 pg/ml.

Conclusion: This is the first study demonstrating the beneficial effect of fetal muscle extract on muscle health in aged mice. Further analysis of the active ingredients of the extract will shed light on the development of a novel treatment for sarcopenia.

The efficacy and safety of Codonopsis lanceolata water extract for sarcopenia: A study protocol for randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

This study aimed to propose a protocol to demonstrate the efficacy of Codonopsis lanceolata water extract for the improvement of skeletal muscle mass (SMM) and function (muscle strength or performance function) and its safety compared to a placebo in adults with reduced muscle strength.

METHODS AND ANALYSIS

A randomized double-blind placebo-controlled clinical trial was conducted. Participants will be recruited from the Korean Medicine Hospital in South Korea. One hundred and four adults with reduced muscle strength will be randomly assigned a 1:1 ratio to either the experimental or placebo comparator groups. The participants will consume the product corresponding to their assigned group for the following 12 weeks, and efficacy and safety tests will be conducted. This is the first clinical trial of C lanceolata water extract in adults with reduced muscle strength. The results of this study would provide a clinical basis for the efficacy and safety of C lanceolata water extract in patients with sarcopenia.

ETHICS AND DISSEMINATION

This trial was approved by the Institutional Review Board (IRB) of Kyung Hee University Korean Medicine Hospital at Gangdong on July 15, 2021 (amendment number: MLB_DDE_H01 [ver. 01]). When a change was made in the clinical trial plan, the IRB reviewed and approved the revised clinical trial plan. The study was registered on the Clinical Research Information Service website on December 3, 2021 (registration number: PRE20211203-003; https://cris.nih.go.kr/cris/search/detailSearch.do?seq=20841&status=1&seq_group=20841&search_page=M). The results of this clinical trial will be reported in the future. Every document related to the clinical trial, such as the electronic case report form, will be recorded and classified by the subject identification code and not by the subject name.

Effects of vibration training vs. conventional resistance training among community-dwelling older people with sarcopenia: three-arm randomized controlled trial protocol

Introduction

Sarcopenia is a chronic and progressive disease, which is accompanied by the decline in muscle mass, muscle strength, and physical performance with aging, and it can lead to falls, fracture, and premature death. The prevention and treatment of sarcopenia mainly include exercise therapy and nutritional supplement. Exercise therapy is one of the most potential interventions to prevent and/or delay the progression of sarcopenia. Resistance training (RT), one of the most commonly used exercise types, is widely used in the treatment of sarcopenia, while vibration training (VT) is a prospective strategy for improving sarcopenia in older people. The aim of our study is to compare the effect of VT and RT in older people with sarcopenia on muscle mass, muscle strength, physical performance, blood biomarkers, and quality of life.

Methods and analysis

Our study is a 12-week, three-arm randomized controlled trial with assessor-blinded. The diagnosis criteria for subject recruitment adopt the guidelines for the Asian Working Group for Sarcopenia. A total of 54 subjects who met the criteria were randomized into one of the following three groups: VT group, RT group, and control group. The VT group and RT group received a 12-week whole-body vibration training and a resistance training program three times every week, respectively. The primary outcome is lower limb muscle strength, and the secondary outcomes include muscle mass, upper limb muscle strength, physical performance, blood biomarkers, and quality of life. We then performed assessments three times, at baseline (0 week), after intervention (12 weeks), and follow-up (24 weeks). The adverse events were also be reported. All outcome measurements were performed by the same researchers. Data were saved in the unified database, and the collected data of all subjects were analyzed by intention-to-treat analysis.

Ethics and dissemination

This study was reviewed and approved by the Ethical Committee of Xinhua Hospital Chongming Branch. The findings of the study were authorized in peer-reviewed journals with online access; meanwhile, it will be presented at domestic or international academic congresses.

Clinical trial registration

Chinese Clinical Trial Registry (ChiCTR2100051178), registered on 15 September 2021.

Puerarin improves skeletal muscle strength by regulating gut microbiota in young adult rats

Background

Sarcopenia is an age-related skeletal muscle dysfunction syndrome that is lacking validated treatments. Maximizing muscle strength in young adulthood may be a promising way to prevent sarcopenia in the elderly. The phytomolecule puerarin has been extensively used in clinical practice and reported to increase energy metabolism in skeletal muscle by directly targeting the skeletal muscle fiber. However, the bioavailability of puerarin is very poor, and almost 93% of puerarin stays in the intestine until excretion. Therefore, we hypothesize that puerarin may regulate gut microbiota to improve skeletal muscle strength and/or mass in adults.

Methods

Twenty three-month old male Sprague Dawley rats were divided into two groups according to average weights, puerarin group (puerarin dissolved in 0.5% CMC-Na, 150 ​mg/kg/day, N ​= ​10), and control group (equal volume 0.5% CMC-Na, N ​= ​10). The treatment lasted for 8 weeks. Muscle weight, muscle fiber types and cross-sectional area (CSA), ex vivo muscle contraction test and grip strength were measured. 16S rDNA sequencing was employed to evaluate the gut microbiota composition in the sample of cecal content. Short-chain fatty acids (SCFAs) in cecal and serum were analyzed by gas chromatography-mass spectrometry. Adenosine triphosphate (ATP) concentration in skeletal muscle was also detected. Pearson's correlation was used to analyze the relations between SCFAs, ATP concentration and muscle function.

Results

After puerarin treatment, grip strength, the specific twitch force, and the tetanic forces in the soleus (SOL) and extensor digitorum longus (EDL) muscle were significantly higher than those of the control group. The percentage and CSA of type II muscle fiber in EDL was higher in the puerarin group than those in the control group. Puerarin treatment significantly changed the gut microbial constitutes. Two SCFAs-productive microbiota, the families Peptococcaceae and Closteridiales, were significantly higher in the puerarin group than those in the control group, while the ratio of Prevotellaceae/Bacteroidaceae (P/B), a muscle atrophy indicator, was lower in the puerarin group. As expected, there were significant linear correlations between the concentrations of SCFAs, including cecal total SCFAs, serum n-butyric acid and total SCFAs, and skeletal muscle strength and function, including the twitch force and tetanic force of SOL and EDL, as well as the forelimb grip strength.

Conclusion

In conclusion, puerarin improved the forelimb grip strength and muscle contraction function in young adult rats. The underlying mechanism may include that puerarin increased SCFAs production by regulating gut microbiota, augmented ATP synthesis and skeletal muscle strength.

The translational potential of this article: Our study finds that a clinical used phytomolecule puerarin has the potential of improving skeletal muscle strength in young adult rats. As puerarin has long-term clinical experience and shows good safety, it might be a potential candidate for developing muscle strengthening agents.

Exercise and Nutrition Strategies for Combating Sarcopenia and Type 2 Diabetes Mellitus in Older Adults

Medical and technology development have drastically the improved quality of life and, consequently, life expectancy. Nevertheless, the more people who enter the third-age, the more geriatric syndromes expand in the elderly. Sarcopenia and Type 2 diabetes mellitus (T2DM) are common diseases among the elderly and the literature has extensively studied these two diseases separately. Recent evidence, however, revealed that there is a bidirectional relationship between sarcopenia and T2DM. The aims of the present review were: (1) to present diet and exercise interventions for the management of sarcopenia and T2DM and (2) identify which diet and exercise interventions can be used simultaneously in order to effectively deal with these two disorders. Exercise and a balanced diet are used as effective countermeasures for combating sarcopenia and T2DM in older adults based on their bidirectional relationship. Lifestyle changes such as exercise and a balanced diet seem to play an important role in the remission of the diseases. Results showed that chronic exercise can help towards glycemic regulation as well as decrease the incidence rate of muscle degradation, while diet interventions which focus on protein or amino acids seem to successfully treat both disorders. Despite the fact that there are limited studies that deal with both disorders, it seems that a combined exercise regime (aerobic and resistance) along with protein intake > 1gr/kg/d is the safest strategy to follow in order to manage sarcopenia and T2DM concurrently.

Impact of Sarcopenia and Bone Mineral Density on Implant Failure after Dorsal Instrumentation in Patients with Osteoporotic Vertebral Fractures

Background and Objectives: Age-related loss of bone and muscle mass are signs of frailty and are associated with an increased risk of falls and consecutive vertebral fractures. Management often necessitates fusion surgery. We determined the impacts of sarcopenia and bone density on implant failures (IFs) and complications in patients with spondylodesis due to osteoporotic vertebral fractures (OVFs). Materials and Methods: Patients diagnosed with an OVF according to the osteoporotic fracture classification (OF) undergoing spinal instrumentation surgery between 2011 and 2020 were included in our study. The skeletal muscle area (SMA) was measured at the third lumbar vertebra (L3) level using axial CT images. SMA z-scores were calculated for the optimal height and body mass index (BMI) adjustment (zSMA_HT). The loss of muscle function was assessed via measurement of myosteatosis (skeletal muscle radiodensity, SMD) using axial CT scans. The bone mineral density (BMD) was determined at L3 in Hounsfield units (HU). Results: A total of 68 patients with OVFs underwent instrumentation in 244 segments (mean age 73.7 ± 7.9 years, 60.3% female). The median time of follow-up was 14.1 ± 15.5 months. Sarcopenia was detected in 28 patients (47.1%), myosteatosis in 45 patients (66.2%), and osteoporosis in 49 patients (72%). The presence of sarcopenia was independent of chronological age (p = 0.77) but correlated with BMI (p = 0.005). The zSMA_HT was significantly lower in patients suffering from an IF (p = 0.0092). Sarcopenia (OR 4.511, 95% CI 1.459–13.04, p = 0.0092) and osteoporosis (OR 9.50, 95% CI 1.497 to 104.7, p = 0.014) increased the likelihood of an IF. Using multivariate analysis revealed that the zSMA_HT (p = 0.0057) and BMD (p = 0.0041) were significantly related to IF occurrence. Conclusion: Herein, we established sarcopenic obesity as the main determinant for the occurrence of an IF after instrumentation for OVF. To a lesser degree, osteoporosis was associated with impaired implant longevity. Therefore, measuring the SMA and BMD using an axial CT of the lumbar spine might help to prevent an IF in spinal fusion surgery via early detection and treatment of sarcopenia and osteoporosis.

Design, Characterization, and In Vitro Assays on Muscle Cells of Endocannabinoid-like Molecule Loaded Lipid Nanoparticles for a Therapeutic Anti-Inflammatory Approach to Sarcopenia

Inflammatory processes play a key role in the pathogenesis of sarcopenia owing to their effects on the balance between muscle protein breakdown and synthesis. Palmitoylethanolamide (PEA), an endocannabinoid-like molecule, has been well documented for its anti-inflammatory properties, suggesting its possible beneficial use to counteract sarcopenia. The promising therapeutic effects of PEA are, however, impaired by its poor bioavailability. In order to overcome this limitation, the present study focused on the encapsulation of PEA in solid lipid nanoparticles (PEA-SLNs) in a perspective of a systemic administration. PEA-SLNs were characterized for their physico-chemical properties as well as cytotoxicity and cell internalization capacity on C2C12 myoblast cells. Their size was approximately 250 nm and the encapsulation efficiency reached 90%. Differential scanning calorimetry analyses demonstrated the amorphous state of PEA in the inner SLN matrix, which improved PEA dissolution, as observed in the in vitro assays. Despite the high internalization capacity observed with the flow cytometer (values between 85 and 94% after 14 h of incubation), the Nile Red labeled PEA-SLNs showed practically no toxicity towards myoblasts. Confocal analysis showed the presence of SLNs in the cytoplasm and not in the nucleus. These results suggest the potentiality provided by PEA-SLNs to obtain an innovative and side-effect-free tool in the medical treatment of sarcopenia.

Declined expressions of vast mitochondria-related genes represented by CYCS and transcription factor ESRRA in skeletal muscle aging

Age-related skeletal muscle deterioration (sarcopenia) has a significant effect on the elderly's health and quality of life, but the molecular and gene regulatory mechanisms remain largely unknown. It is necessary to identify the candidate genes related to skeletal muscle aging and prospective therapeutic targets for effective treatments. The age-line-related genes (ALRGs) and age-line-related transcripts (ALRTs) were investigated using the gene expression profiles of GSE47881 and GSE118825 from the Gene Expression Omnibus (GEO) database. The protein-protein interaction (PPI) networks were performed to identify the key molecules with Cytoscape, and Gene Set Enrichment Analysis (GSEA) was used to clarify the potential molecular functions. Two hub molecules were finally obtained and verified with quantitative real-time PCR (qRT-PCR). The results showed that the expression of mitochondria genes involved in mitochondrial electron transport, complex assembly of the respiratory chain, tricarboxylic acid cycle, oxidative phosphorylation, and ATP synthesis were down-regulated in skeletal muscle with aging. We further identified a primary hub gene of CYCS (Cytochrome C) and a key transcription factor of ESRRA (Estrogen-related Receptor Alpha) to be associated closely with skeletal muscle aging. PCR analysis confirmed the expressions of CYCS and ESRRA in gastrocnemius muscles of mice of different ages were significantly different, and decreased gradually with age. In conclusion, the main cause of skeletal muscle aging may be the systematically reduced expression of mitochondrial functional genes. The CYCS and ESRRA may play significant roles in the progression of skeletal muscle aging and serve as potential biomarkers for future diagnosis and treatment.

Effects of Protein-Rich Nutritional Composition Supplementation on Sarcopenia Indices and Physical Activity during Resistance Exercise Training in Older Women with Knee Osteoarthritis

Older adults with knee osteoarthritis (KOA) are at high risk of sarcopenia. Protein-rich nutritional composition supplementation (PS) combined with resistance exercise training (RET) improves muscle gains and facilitates physical activity in older adults. However, whether PS augments the effects of RET on muscle mass and PA in patients with KOA remains unclear. Therefore, this study identified the effects of PS on sarcopenic indices and PA in older women with KOA subjected to an RET program. Eligible older women aged 60–85 years and diagnosed as having KOA were randomly assigned to either the experimental group (EG) or the control group (CG). Both groups performed RET twice a week for 12 weeks. The EG received additional PS during this period. Outcome measures included appendicular lean mass index, walking speed, physical activity, and scores on the Western Ontario and McMaster Universities Osteoarthritis Index—WOMAC). All measures were tested at baseline and after intervention. With participant characteristics and baseline scores as covariates, analysis of variance was performed to identify between-group differences in changes in all outcome measures after intervention. Statistical significance was defined as p < 0.05. Compared with the CG, the EG achieved greater changes in appendicular lean mass index (adjusted mean difference (aMD) = 0.19 kg/m², p < 0.01), physical activity (aMD = 30.0 MET-hour/week, p < 0.001), walking speed (aMD = 0.09 m/s, p < 0.05), and WOMAC global function (aMD = −8.21, p < 0.001) after intervention. In conclusion, PS exerted augmentative effects on sarcopenic indices, physical activity, and perceived global WOMAC score in older women with KOA through 12 weeks of RET.

Differential gene expression profile by RNA sequencing study of elderly osteoporotic hip fracture patients with sarcopenia

Background

The purpose of this study was to report the RNA sequencing profile according to the presence or absence of sarcopenia in elderly patients with osteoporotic hip fracture. Therefore, an important genetic factor candidate for sarcopenia causing hip fracture in elderly with osteoporosis has been identified.

Methods

The patient group involved subjects over 65 years who had undergone hip fracture surgery. Among 323 hip fracture (HF) patients identified from May 2017 to December 2019, 162 HF patients (90 non-sarcopenia and 72 sarcopenia groups), excluding subjects with high energy trauma and non-osteoporosis, were finally included in the analysis. For RNA sequencing, each patient with hand grip strength (HGS) values in the top 10% were enrolled in the control group and with the bottom 10% in the patient group. After excluding patients with poor tissue quality, 6 patients and 5 patients were selected for sarcopenia and non-sarcopenia groups, respectively. For qPCR validation, each patient with HGS values in the top 20% and bottom 20% was enrolled in the control and patient groups, respectively. After excluding patients with poor tissue quality, 12 patients and 12 patients were enrolled in the sarcopenia and non-sarcopenia groups, respectively. Sarcopenia was defined according to the Asia Working Group for Sarcopenia (AWGS) criteria for low muscle strength (hand grip strength below 18 ​kg in women and 28 ​kg in men) and low muscle mass (SMI below 5.4 ​kg/m² in women and 7.0 ​kg/m² in men). The libraries were prepared for 100 bp paired-end sequencing using TruSeq Stranded mRNA Sample Preparation Kit (Illumina, CA, USA). The gene expression counts were supplied to Deseq2 to extract possible gene sets as differentially expressed genes (DEG) that discriminate between sarcopenia and non-sarcopenia groups that were carefully assigned by clinical observation. For the classification of the candidate genes from DEG analysis, we used the public databases; gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Quantitative real-time PCR was performed for validation.

Results

Samples collected were subjected to RNAseq using the Illumina platform. A total of 11 samples from both sarcopenia and non-sarcopenia groups were sequenced. Fifteen genes (RUNX 1, NGFR, CH3L1, BCL3, PLA2G2A, MYBPH, TEP1, SEMA6B, CSPG4, ACSL5, SLC25A3, NDUFB5, CYC1, ACAT1, and TCAP) were identified as differentially expressed genes (DEG) in both the groups.

In the qPCR results, the expression levels of SLC25A3 and TCAP gene in the OS group were significantly lower than in the non-OS groups whereas an increase in RUNX1 mRNA level was observed in the OS samples (p ​< ​0.05).

Conclusions

In summary, this study detected gene expression difference according to the presence or absence of sarcopenia in elderly osteoporosis female patients with hip fracture. We have also identified 15 important genes (RUNX 1, NGFR, CH3L1, BCL3, PLA2G2A, MYBPH, TEP1, SEMA6B, CSPG4, ACSL5, SLC25A3, NDUFB5, CYC1, ACAT1, TCAP), a few GO categories and biological pathways that may be associated with the osteosarcopenia. Our study may provide effective means for the prevention, diagnosis and treatment sarcopenia in elderly osteoporosis female patients.

The Translational potential of this article

These findings provide a novel insight into the effects of aging on the response in women with postmenopausal osteoporosis. Further studies are underway to identify the specific signalling pathways involved. These results reveal potential therapeutic targets that could aid the regenerative capacity of aging skeletal muscle.

Emerging Treatment Options for Sarcopenia in Chronic Liver Disease

Sarcopenia is characterized by a skeletal muscle disorder with progressive and generalized loss of muscle mass and function, and it increases the risk of adverse outcomes with considerable prevalence in patients with chronic liver disease. Sarcopenia in chronic liver disease underlies complicated and multifactorial mechanisms for pathogenesis, including alterations in protein turnover, hyperammonemia, energy disposal, hormonal changes, and chronic inflammation. The key contribution to sarcopenia in patients with chronic liver diseases can be the hyperammonemia-induced upregulation of myostatin, which causes muscle atrophy via the expression of atrophy-related genes. Several clinical studies on emerging treatment options for sarcopenia have been reported, but only a few have focused on patients with chronic liver diseases, with mostly nutritional and behavioral interventions being carried out. The inhibition of the myostatin-activin receptor signaling pathway and hormonal therapy might be the most promising therapeutic options in combination with an ammonia-lowering approach in sarcopenic patients with chronic liver diseases. This review focuses on current and emerging treatment options for sarcopenia in chronic liver diseases with underlying mechanisms to counteract this condition.

Specialized, pro-resolving mediators as potential therapeutic agents for alleviating fibromyalgia symptomatology

OBJECTIVE

To present a hypothesis on a novel strategy in the treatment of fibromyalgia (FM).

DESIGN

A narrative review.

SETTING

FM as a disease remains a challenging concept for numerous reasons, including undefined etiopathogenesis, unclear triggers and unsuccessful treatment modalities. We hypothesize that the inflammatome, the entire set of molecules involved in inflammation, acting as a common pathophysiological instrument of gut dysbiosis, sarcopenia, and neuroinflammation, is one of the major mechanisms underlying FM pathogenesis. In this setup, dysbiosis is proposed as the primary trigger of the inflammatome, sarcopenia as the peripheral nociceptive source, and neuroinflammation as the central mechanism of pain sensitization, transmission and symptomatology of FM. Whereas neuroinflammation is highly-considered as a critical deleterious element in FM pathogenesis, the presumed pathogenic roles of sarcopenia and systemic inflammation remain controversial. Nevertheless, sarcopenia-associated processes and dysbiosis have been recently detected in FM individuals. The prevalence of pro-inflammatory factors in the cerebrospinal fluid and blood has been repeatedly observed in FM individuals, supporting an idea on the role of inflammatome in FM pathogenesis. As such, failed inflammation resolution might be one of the underlying pathogenic mechanisms. In accordance, the application of specialized, inflammation pro-resolving mediators (SPMs) seems most suitable for this goal.

CONCLUSIONS

The capability of various SPMs to prevent and attenuate pain has been repeatedly demonstrated in laboratory animal experiments. Since SPMs suppress inflammation in a manner that does not compromise host defense, they could be attractive and safe candidates for the alleviation of FM symptomatology, probably in combination with anti-dysbiotic medicine.

Factors significantly associated with COVID-19 severity in symptomatic patients: A retrospective single-center study

Introduction

The severity of coronavirus disease (COVID-19) in Japanese patients is unreported. We retrospectively examined significant factors associated with disease severity in symptomatic COVID-19 patients (COVID-Pts) admitted to our institution between February 20 and April 30, 2020.

Methods

All patients were diagnosed based on the genetic detection of severe acute respiratory syndrome coronavirus 2. Information on the initial symptoms, laboratory data, and computed tomography (CT) images at hospitalization were collected from the patients’ records. COVID-Pts were categorized as those with critical or severe illness (Pts-CSI) or those with moderate or mild illness (Pt-MMI). All statistical analyses were performed using R software.

Results

Data from 61 patients (16 Pt–CSI, 45 Pt-MMI), including 58 Japanese and three East Asians, were analyzed. Pt–CSI were significantly older and had hypertension or diabetes than Pt-MMI (P < 0.001, 0.014 and < 0.001, respectively). Serum albumin levels were significantly lower in Pt–CSI than in Pt-MMI (P < 0.001), whereas the neutrophil-to-lymphocyte ratio and C-reactive protein level were significantly higher in Pt–CSI than in Pt-MMI (P < 0.001 and P < 0.001, respectively). In the CT images of 60 patients, bilateral lung lesions were more frequently observed in Pt–CSI than in Pt-MMI (P = 0.013). Among the 16 Pt–CSI, 15 received antiviral therapy, 12 received tocilizumab, five underwent methylprednisolone treatment, six received mechanical ventilation, and one died.

Conclusions

The illness severity of Japanese COVID-Pts was associated with older age, hypertension and/or diabetes, low serum albumin, high neutrophil-to-lymphocyte ratio, and C-reactive protein.