Molecular and Cellular Mechanisms of Muscle Aging and Sarcopenia and Effects of Electrical Stimulation in Seniors

Synergistic effects of graphene microgrooves and electrical stimulation on M2 macrophage polarization

Macrophages play a crucial role in host response and wound healing, with M2 polarization contributing to the reduction of foreign-body reactions induced by the implantation of biomaterials and promoting tissue regeneration. Electrical stimulation (ES) and micropatterned substrates have a significant impact on the macrophage polarization. However, there is currently a lack of well-established cell culture platforms for studying the synergistic effects of these two factors. In this study, we prepared a graphene free-standing substrate with 20 μm microgrooves using capillary forces induced by water evaporation. Subsequently, we established an ES cell culture platform for macrophage cultivation by integrating a self-designed multi-well chamber cell culture device. We observed that graphene microgrooves, in combination with ES, significantly reduce cell spreading area and circularity. Results from immunofluorescence, ELISA, and flow cytometry demonstrate that the synergistic effect of graphene microgrooves and ES effectively promotes macrophage M2 phenotypic polarization. Finally, RNA sequencing results reveal that the synergistic effects of ES and graphene microgrooves inhibit the macrophage actin polymerization and the downstream PI3K signaling pathway, thereby influencing the phenotypic transition. Our results demonstrate the potential of graphene-based microgrooves and ES to synergistically modulate macrophage polarization, offering promising applications in regenerative medicine.

Effects of 12 weeks of neuromuscular electrical stimulation of the quadriceps muscles on the function and physio-biochemical traits in functionally fit female nursing-home residents aged 75 + years: a pilot study

PURPOSE

Muscular changes induced by neuromuscular electrical stimulation (NMES) are well recognized, but knowledge of how NMES influences the physio-biochemical traits of the oldest old is still limited. This study investigated the effect of NMES applied for 12 weeks to the quadriceps muscles of female nursing-home residents aged 75 + on their functional capability and inflammatory, bone metabolism, and cardiovascular traits.

METHODS

Nineteen women regularly taking part in two body conditioning sessions per week were randomized into an electrical stimulation group (ES; n = 10; 30 min sessions, 3 times per week) or a control group (CON; n = 9). At baseline and study week 12, all women performed the 30 s chair stand test (30sCST), the 6-minute walk test (6MWT), and the instrumented timed up and go test (iTUG). Resting heart rates, blood pressure, and the blood concentrations of inflammatory and bone metabolism markers were also measured twice.

RESULTS

NMES increased the strength of participants' quadriceps muscles and their performance on the 30sCST and 6MWT while lowering resting arterial blood pressure and inflammatory marker levels; osteoclast activity showed a tendency to decrease. Changes in the iTUG results were not observed. A multiple regression analysis found that the results of functional tests in the ES group were best correlated with pulse pressure (the 30sCST and iTUG tests) and diastolic blood pressure (the 6MWT test).

CONCLUSION

Twelve weeks of NMES treatment improved participants' functional capacity and inflammatory, bone metabolism, and cardiovascular traits. The ES group participants' performance on functional tests was best predicted by hemodynamic parameters.

Safety and effectiveness of neuromuscular electrical stimulation in cardiac surgery: A systematic review

BACKGROUND

Lack of mobilization and prolonged stay in the intensive care unit (ICU) are major factors resulting in the development of ICU-acquired muscle weakness (ICUAW). ICUAW is a type of skeletal muscle dysfunction and a common complication of patients after cardiac surgery, and may be a risk factor for prolonged duration of mechanical ventilation, associated with a higher risk of readmission and higher mortality. Early mobilization in the ICU after cardiac surgery has been found to be low with a significant trend to increase over ICU stay and is also associated with a reduced duration of mechanical ventilation and ICU length of stay. Neuromuscular electrical stimulation (NMES) is an alternative modality of exercise in patients with muscle weakness. A major advantage of NMES is that it can be applied even in sedated patients in the ICU, a fact that might enhance early mobilization in these patients.

AIM

To evaluate safety, feasibility and effectiveness of NMES on functional capacity and muscle strength in patients before and after cardiac surgery.

METHODS

We performed a search on Pubmed, Physiotherapy Evidence Database (PEDro), Embase and CINAHL databases, selecting papers published between December 2012 and April 2023 and identified published randomized controlled trials (RCTs) that included implementation of NMES in patients before after cardiac surgery. RCTs were assessed for methodological rigor and risk of bias via the PEDro. The primary outcomes were safety and functional capacity and the secondary outcomes were muscle strength and function.

RESULTS

Ten studies were included in our systematic review, resulting in 703 participants. Almost half of them performed NMES and the other half were included in the control group, treated with usual care. Nine studies investigated patients after cardiac surgery and 1 study before cardiac surgery. Functional capacity was assessed in 8 studies via 6MWT or other indices, and improved only in 1 study before and in 1 after cardiac surgery. Nine studies explored the effects of NMES on muscle strength and function and, most of them, found increase of muscle strength and improvement in muscle function after NMES. NMES was safe in all studies without any significant complication.

CONCLUSION

NMES is safe, feasible and has beneficial effects on muscle strength and function in patients after cardiac surgery, but has no significant effect on functional capacity.

Conserved and species-specific transcriptional responses to daily programmed resistance exercise in rat and mouse

Mice are often used in gain or loss of function studies to understand how genes regulate metabolism and adaptation to exercise in skeletal muscle. Once-daily resistance training with electrical nerve stimulation produces hypertrophy of the dorsiflexors in rat, but not in mouse. Using implantable pulse generators, we assessed the acute transcriptional response (1-h post-exercise) after 2, 10, and 20 days of training in free-living mice and rats using identical nerve stimulation paradigms. RNA sequencing revealed strong concordance in the timecourse of many transcriptional responses in the tibialis anterior muscles of both species including responses related to "stress responses/immediate-early genes, and "collagen homeostasis," "ribosomal subunits," "autophagy," and "focal adhesion." However, pathways associated with energy metabolism including "carbon metabolism," "oxidative phosphorylation," "mitochondrial translation," "propanoate metabolism," and "valine, leucine, and isoleucine degradation" were oppositely regulated between species. These pathways were suppressed in the rat but upregulated in the mouse. Our transcriptional analysis suggests that although many pathways associated with growth show remarkable similarities between species, the absence of an actual growth response in the mouse may be because the mouse prioritizes energy metabolism, specifically the replenishment of fuel stores and intermediate metabolites.

Associations between saliva and plasma cytokines in cognitively normal, older adults

BACKGROUND

Inflammatory responses play key roles in the development and progression of many pathological conditions, including neurodegenerative diseases. Accurate quantification of inflammatory factors in saliva would be highly advantageous, given its convenience and non-invasive nature, especially in elderly populations.

METHODS

In this study, we measured levels of 10 cytokines, and the pro-inflammatory factor, YKL-40, in plasma and saliva samples from a cohort of nondemented older adults (n = 71; 62% female; 70.3 ± 6.4 years) using sensitive electrochemiluminescence-based immunoassays.

RESULTS

We found that the mean levels of all cytokines were higher in saliva compared to plasma and that strong sex differences were observed for both saliva and plasma cytokines in this population. Comparing each cytokine between the two biofluids, we found that levels of interferon-gamma (IFNγ), interleukin (IL)-6 and tumor necrosis factor-alpha (TNFα) in blood were significantly correlated with their respective levels in saliva. We further observed that levels of these cytokines in blood were significantly correlated with additional cytokines in saliva, including IL-1β, IL-10, IL-8, IL12p70 and IL-13.

CONCLUSIONS

These findings show that inflammatory markers in saliva are associated with those found in circulation, suggesting shared inflammatory mechanisms between these two fluids. The higher levels of cytokines measured in saliva suggest that it might represent a better peripheral fluid to gauge inflammatory processes. Finally, our findings of robust sex differences in several salivary cytokines could have important implications for their potential use as disease biomarkers in the elderly and might be related to sex differences in the prevalence of age-related conditions.

Ferroptosis and musculoskeletal diseases: “Iron Maiden” cell death may be a promising therapeutic target

Ferroptosis is a novel form of cell death precisely regulated by iron metabolism, antioxidant processes, and lipid metabolism that plays an irreplaceable role in the development of many diseases. Musculoskeletal disorders (MSKs), including osteoporosis, osteoarthritis, rheumatoid arthritis, intervertebral disc degeneration, sarcopenia, and rhabdomyolysis, have become one of the most common causes of disability and a major burden on public health and social care systems. The mechanism of ferroptosis in MSKs has recently been elucidated. In this review, we briefly introduce the ferroptosis mechanism and illustrate the pathological roles of ferroptosis in MSKs with a focus on how ferroptosis can be exploited as a promising treatment strategy. Notably, because the toxicity of compounds that inhibit or induce ferroptosis in other organs is largely unknown, ferroptosis appears to be a double-edged sword. We point out that more research is needed in the future to verify the therapeutic effects based on ferroptosis in MSKs.

The ongoing effects of the COVID-19 pandemic on perceived physical activity, physical function and mood of older adults in the U.K: A follow-up study (March 2020-June 2021)

Coronavirus (COVID-19) and its variants, continue to spread globally more than two years after the discovery of the wild-type virus in Wuhan, China. Following the onset of COVID-19, fluctuating restrictions have likely impacted the daily lives of older adults living in the United Kingdom (UK). Subsequently, the longer term effects of COVID-19 on physical activity levels, perceived physical function and mood of older adults are unclear. Therefore, the present study aimed to follow a group of older adult's living in the UK for one year, to monitor physical activity levels, perceived physical function and mood. A longitudinal, mixed-methods, observational study was conducted using self-administered, online surveys at 3-month intervals between March 2020 and June 2021. A total of 100 participants (46 males [age: 76 ± 5 years] and 54 females [age:74 ± 4 years]) completed all surveys. Bayesian analysis allowed calculation of direct probabilities whilst incorporating our prior knowledge. Throughout this period, older adults maintained or increased their pre-lockdown physical activity levels despite a decrease in intensity of effort of physical activity tasks, whilst sitting time increased at two of the follow-up time-points. Furthermore, perceived physical function decreased (ps = 91.78%;>1.21 AU) and mood undulated in a pattern that reflected the tightening and easing of restrictions. Despite total physical activity being maintained, perceived physical function decreased by a small but clinically meaningful margin.

Association between prognosis and the use of angiotensin‐converting enzyme inhibitors and/or angiotensin II receptor blockers in frail patients with heart failure with preserved ejection fraction

Aims

The effectiveness of angiotensin‐converting enzyme inhibitors (ACE‐I) and angiotensin II receptor blockers (ARB) has not been demonstrated in patients with heart failure with preserved ejection fraction (HFpEF). We recently reported significant interaction between the use of ACE‐I and/or ARB (ACE‐I/ARB) and frailty on prognosis in patients with HFpEF. In the present study, we examined the association between ACE‐I/ARB and prognosis in patients with HFpEF stratified by the presence or absence of frailty.

Methods and results

We examined the association between the use of ACE‐I/ARB and prognosis according to the presence [Clinical Frailty Scale (CFS) ≥ 5] or absence (CFS ≤ 4) of frailty in patients with HFpEF in a post hoc analysis of registry data. Primary endpoint was the composite of all‐cause mortality and heart failure admission. Secondary endpoints were all‐cause mortality and heart failure admission. Of 1059 patients, median age was 83 years and 45% were male. Kaplan–Meier analysis showed that the risk of composite endpoint (log‐rank P = 0.001) and all‐cause death (log‐rank P = 0.005) in patients with ACE‐I/ARB was lower in those with CFS ≥ 5, but similar between patients with and without ACE‐I/ARB in patients with CFS ≤ 4 (composite endpoint: log‐rank P = 0.830; all‐cause death: log‐rank P = 0.192). In a multivariable Cox proportional hazards model, use of ACE‐I/ARB was significantly associated with lower risk of the composite endpoint [hazard ratio (HR) = 0.52, 95% confidence interval (CI) = 0.33–0.83, P = 0.005] and heart failure admission (HR = 0.45, 95% CI = 0.25–0.83, P = 0.010) in patients with CFS ≥ 5, but not in patients with CFS ≤ 4 (composite endpoint: HR = 1.41, 95% CI = 0.99–2.02, P = 0.059; heart failure admission: HR = 1.43, 95% CI = 0.94–2.18, P = 0.091). The association between ACE‐I or ARB and prognosis did not significantly differ by CFS (CFS ≤ 4: log‐rank P = 0.562; CFS ≥ 5: log‐rank P = 0.100, for with ACE‐I vs. ARB, respectively). Adjusted HRs for CFS 1–4 were higher than 1.0 but were <1.0 at CFS 5.

Conclusions

In patients with HFpEF, use of ACE‐I/ARB was associated with better prognosis in patients with frailty as assessed with the CFS, but not in those without frailty.

Exercise Therapy for People With Sarcopenic Obesity: Myokines and Adipokines as Effective Actors

Sarcopenic obesity is defined as a multifactorial disease in aging with decreased body muscle, decreased muscle strength, decreased independence, increased fat mass, due to decreased physical activity, changes in adipokines and myokines, and decreased satellite cells. People with sarcopenic obesity cause harmful changes in myokines and adipokines. These changes are due to a decrease interleukin-10 (IL-10), interleukin-15 (IL-15), insulin-like growth factor hormone (IGF-1), irisin, leukemia inhibitory factor (LIF), fibroblast growth factor-21 (FGF-21), adiponectin, and apelin. While factors such as myostatin, leptin, interleukin-6 (IL-6), interleukin-8 (IL-8), and resistin increase. The consequences of these changes are an increase in inflammatory factors, increased degradation of muscle proteins, increased fat mass, and decreased muscle tissue, which exacerbates sarcopenia obesity. In contrast, exercise, especially strength training, reverses this process, which includes increasing muscle protein synthesis, increasing myogenesis, increasing mitochondrial biogenesis, increasing brown fat, reducing white fat, reducing inflammatory factors, and reducing muscle atrophy. Since some people with chronic diseases are not able to do high-intensity strength training, exercises with blood flow restriction (BFR) are newly recommended. Numerous studies have shown that low-intensity BFR training produces the same increase in hypertrophy and muscle strength such as high-intensity strength training. Therefore, it seems that exercise interventions with BFR can be an effective way to prevent the exacerbation of sarcopenia obesity. However, due to limited studies on adipokines and exercises with BFR in people with sarcopenic obesity, more research is needed.

Neuromuscular or Sensory Electrical Stimulation for Reconditioning Motor Output and Postural Balance in Older Subjects?

Percutaneous electrical stimulation is used for reconditioning functional capabilities in older subjects. However, its optimal application depends on the specific physiological needs of the individual. Depending on whether his/her needs are related to motor function or sensory and central functions, the relevant modality of electrical stimulation differs significantly. In fact, there are two main modalities of electrical stimulation, that is, neuromuscular electrical stimulation (NMES) and sensory electrical stimulation (SES). NMES involves high-intensity currents (above the motor threshold) and provokes involuntary visible direct muscle contractions. With chronic application, the induced adaptations occur mainly at the neuromuscular function level and thus enhance muscle strength/power and motor output. SES involves low-intensity currents (below, at or only just above the sensory threshold), does not induce any visible muscle contraction and provides only sensory information. With chronic application, the induced adaptations occur at the level of potentiation and transmission of proprioceptive afferents and thus facilitate sensorimotor activity (movement and balance). Overall, SES is interesting for the improvement/maintenance of sensorimotor capabilities in non-frail older subjects while NMES is relevant to develop muscle strength/power and thus reduce the risk of falls due to a lack of muscle strength/power in frail older subjects.

Depression and Life Satisfaction Among Middle-Aged and Older Adults: Mediation Effect of Functional Disability

With increasing age, middle-aged and older persons face a series of physical and mental health problems. This study aimed to explore the latent relationships among age, functional disability, depression, and life satisfaction. The data were obtained from the Wave 2 (in 2013–2014) and Wave 3 (in 2015–2016) surveys of the China Health and Retirement Longitudinal Study. The analytic sample in the present study included 15,950 individuals aged 45 years and over. The participants answered the same questions concerning depression and life satisfaction in both study waves, and functional disability was measured based on the activities of daily living and instrumental activities of daily living. Age was directly associated with functional disability, life satisfaction, and depression. Functional disability was positively correlated with depression and negatively correlated with life satisfaction. Functional disability strongly mediated the relationships among age, depression, and life satisfaction. Depression and life satisfaction were found to have enduring effects and effects on each other. Additionally, the model revealed a gender difference. Depression in middle-aged people should receive closer attention. Avoiding or improving functional disability may be an effective way to improve life satisfaction and reduce the level of depression in middle-aged and older persons. If prevention work successfully decreases depression, the life dissatisfaction of middle-aged and older people could be improved. Additionally, for the prevention of functional disability and depression and improvement in life satisfaction, gender differences need to be considered.

Soft tissue radiodensity parameters mediate the relationship between self-reported physical activity and lower extremity function in AGES-Reykjavík participants

Although previous studies have highlighted the association between physical activity and lower extremity function (LEF) in elderly individuals, the mechanisms underlying this relationship remain debated. Our recent work has recognized the utility of nonlinear trimodal regression analysis (NTRA) parameters in characterizing changes in soft tissue radiodensity as a quantitative construct for sarcopenia in the longitudinal, population-based cohort of the AGES-Reykjavík study. For the present work, we assembled a series of prospective multivariate regression models to interrogate whether NTRA parameters mediate the 5-year longitudinal relationship between physical activity and LEF in AGES-Reykjavík participants. Healthy elderly volunteers from the AGES-Reykjavík cohort underwent mid-thigh X-ray CT scans along with a four-part battery of LEF tasks: normal gait speed, fastest-comfortable gait speed, isometric leg strength, and timed up-and-go. These data were recorded at two study timepoints which were separated by approximately 5 years: AGES-I (n = 3157) and AGES-II (n = 3098). Participants in AGES-I were likewise administered a survey to approximate their weekly frequency of engaging in moderate-to-vigorous physical activity (PAAGES-I). Using a multivariate mediation analysis framework, linear regression models were assembled to test whether NTRA parameters mediated the longitudinal relationship between PAAGES-I and LEFAGES-II; all models were covariate-adjusted for age, sex, BMI, and baseline LEF, and results were corrected for multiple statistical comparisons. Our first series of models confirmed that all four LEF tasks were significantly related to PAAGES-I; next, modelling the relationship between PAAGES-I and NTRAAGES-II identified muscle amplitude (Nm) and location (μm) as potential mediators of LEF to test. Finally, adding these two parameters into our PAAGES-I → LEFAGES-II models attenuated the prior effect of PAAGES-I; bootstrapping confirmed Nm and μm as significant partial mediators of the PAAGES-I → LEFAGES-II relationship, with the strongest effect found in isometric leg strength. This work describes a novel approach toward clarifying the mechanisms that underly the relationship between physical activity and LEF in aging individuals. Identifying Nm and μm as significant partial mediators of this relationship provides strong evidence that physical activity protects aging mobility through the preservation of both lean tissue quantity and quality.

Testing soft tissue radiodensity parameters interplay with age and self-reported physical activity

Aging well is directly associated to a healthy lifestyle. The focus of this paper is to relate individual wellness with medical image features. Non-linear trimodal regression analysis (NTRA) is a novel method that models the radiodensitometric distributions of x-ray computed tomography (CT) cross-sections. It generates 11 patient-specific parameters that describe the quality and quantity of muscle, fat, and connective tissues. In this research, the relationship of these 11 NTRA parameters with age, physical activity, and lifestyle is investigated in the 3,157 elderly volunteers AGES-I dataset. First, univariate statistical analyses were performed, and subjects were grouped by age and self-reported past (youth–midlife) and present (within 12 months of the survey) physical activity to ascertain which parameters were the most influential. Then, machine learning (ML) analyses were conducted to classify patients using NTRA parameters as input features for three ML algorithms. ML is also used to classify a Lifestyle index using the age groups. This classification analysis yielded robust results with the lifestyle index underlying the relevant differences of the soft tissues between age groups, especially in fat and connective tissue. Univariate statistical models suggested that NTRA parameters may be susceptible to age and differences between past and present physical activity levels. Moreover, for both age and physical activity, lean muscle parameters expressed more significant variation than fat and connective tissues.

Prognostic impact of Clinical Frailty Scale in patients with heart failure with preserved ejection fraction

Aims

Frailty is associated with prognosis of cardiovascular diseases. However, the significance of frailty in patients with heart failure with preserved ejection fraction (HFpEF) remains to be elucidated. The purpose of this study was to examine the prognostic significance of the Clinical Frailty Scale (CFS) in real‐world patients with HFpEF using data from a prospective multicentre observational study of patients with HFpEF (PURSUIT‐HFpEF study).

Method and Results

We classified 842 patients with HFpEF enrolled in the PURSUIT‐HFpEF study into two groups using CFS. The registry enrolled patients hospitalized with a diagnosis of decompensated heart failure. Median age was 82 [interquartile range: 77, 87], and 45% of the patients were male. Of 842 patients, 406 were classified as high CFS (CFS ≥ 4, 48%) and 436 as low CFS (CFS ≤ 3, 52%). The primary endpoint was the composite of all‐cause mortality and heart failure admission. Secondary endpoints were all‐cause mortality and heart failure admission. Patients with high CFS were older (85 vs. 79 years, P < 0.001), predominantly female (65% vs. 46%, P < 0.001) and more likely to have New York Heart Association (NYHA) ≥ 2 (75% vs. 53%, P < 0.001) and a higher level of NT‐proBNP (1360 vs 838 pg/mL, P < 0.001) than those with low CFS. Patients with high CFS had a significantly greater risk of composite endpoint (Kaplan–Meier estimated 1‐year event rate 39% vs. 23%, log‐rank P < 0.001), all‐cause mortality (Kaplan–Meier estimated 1‐year event rate 17% vs. 7%, log‐rank P < 0.001) and heart failure admission (Kaplan–Meier estimated 1‐year event rate 28% vs. 19%, log‐rank P = 0.002) than those with low CFS. Multivariable Cox regression analysis revealed that high CFS was significantly associated with composite endpoint (adjusted HR 1.92, 95% CI 1.35–2.73, P < 0.001), all‐cause mortality (adjusted HR 2.54, 95% CI 1.39–4.66, P = 0.003) and heart failure admission (adjusted HR 1.55, 95% CI 1.03–2.32, P = 0.035) even after adjustment for covariates. Moreover, change in CFS grade was also significantly associated with composite endpoint (adjusted HR 1.23, 95% CI 1.11–1.36, P < 0.001), all‐cause mortality (adjusted HR 1.32, 95% CI 1.13–1.55, P = 0.001) and heart failure admission (adjusted HR 1.15, 95% CI 1.02–1.30, P = 0.021).

Conclusions

Frailty assessed by the CFS was associated with poor prognosis in patients with HFpEF.

Quantitative Proteomics Analysis for the Identification of Differential Protein Expression in Calf Muscles between Young and Old SD Rats Using Mass Spectrometry

Aging is associated with loss of muscle mass and strength that leads to a condition termed sarcopenia. Impaired conditions, morbidity, and malnutrition are the factors of devaluation of muscle fibers in aged animals. Satellite cells play an important role in maintaining muscle homeostasis during tissue regeneration and repair. Proteomic profiling on the skeletal muscle tissues of different age group rats helps to determine the differentially expressed (DE) proteins, which may eventually lead to the development of biomarkers in treating the conditions of sarcopenia. In this study, nanoscale liquid chromatography coupled to tandem mass spectrometry (nano-LC-MS/MS) analysis was implemented in the calf tissues of young and old groups of rats. The mass spectrometry (MS) analysis revealed the presence of 335 differentially expressed proteins between the two different age conditions, among which those based on log-fold change 25 proteins were upregulated and 77 were downregulated. The protein-protein interaction network analysis revealed 18 upregulated proteins with three distinct interconnected networks and 57 downregulated proteins with two networks. Further, gene ontology (GO) enrichment analysis showed the biological process, cellular component, and molecular function of the differential proteins. Pathway enrichment analysis of the DE proteins identified nine significantly enriched pathways with a list of eight significant genes (Cryab, Hspb2, Acat1, Ak1, Adssl1, Anxa5, Gys1, Ogdh, Gc, and Adssl1). Quantification of significant genes by quantitative real-time polymerase chain reaction (qRT-PCR) confirmed the downregulation at the mRNA level. Western blot analysis of their protein expression showed concordant results on two candidate proteins (Ogdh and annexin 5) confirming their differential regulation between the two age groups of rats. Thus, these proteomic approaches on young and aged rats provide insights into the development of protein targets in the treatment of sarcopenia (muscle loss).

Nanomaterial Additives for Fabrication of Stimuli-Responsive Skeletal Muscle Tissue Engineering Constructs

Volumetric muscle loss necessitates novel tissue engineering strategies for skeletal muscle repair, which have traditionally involved cells and extracellular matrix-mimicking scaffolds and have thus far been unable to successfully restore physiologically relevant function. However, the incorporation of various nanomaterial additives with unique physicochemical properties into scaffolds has recently been explored as a means of fabricating constructs that are responsive to electrical, magnetic, and photothermal stimulation. Herein, several classes of nanomaterials that are used to mediate external stimulation to tissue engineered skeletal muscle are reviewed and the impact of these stimuli-responsive biomaterials on cell growth and differentiation and in vivo muscle repair is discussed. The degradation kinetics and biocompatibilities of these nanomaterial additives are also briefly examined and their potential for incorporation into clinically translatable skeletal muscle tissue engineering strategies is considered. Overall, these nanomaterial additives have proven efficacious and incorporation in tissue engineering scaffolds has resulted in enhanced functional skeletal muscle regeneration.

The influence of COVID-19 measures in the United Kingdom on physical activity levels, perceived physical function and mood in older adults: A survey-based observational study

In March 2020, the spreading Coronavirus (COVID-19) prompted the United Kingdom government to introduce a societal shutdown, accompanied by self-isolation and social-distancing measures to reduce virus transmission. In doing so, opportunities for physical activity were likely reduced, potentially causing detrimental effects to older adults. Therefore, the present study investigated the influence of the initial six weeks of lockdown on physical activity levels, perceived physical function and mood in older adults. A cross-sectional, mixed-methods, observational study was conducted using self-administered, fortnightly online surveys throughout the UK between 21^st March-4 May 2020. A total of 117 participants (52 males [age: 76 ± 4 years] and 65 females [age: 76 ± 4 years]) completed all surveys. Despite lockdown restrictions, this group of older adults maintained their pre-lockdown physical activity levels, but also increased their self-reported sedentary time. Subsequently, perception of physical function was maintained across lockdown. With regards to mood; the only strong evidence for an increase in depression was for males (ps = 95.35%; >0.3 AU), although self-reported levels of depression were similar between sexes at week six. Given the link between sedentary behaviour and negative health outcomes in older adults, strategies to reduce sedentariness during the COVID-19 pandemic are required.

16th Meeting of the Interuniversity Institute of Myology (IIM) - Assisi (Italy), October 17-20, 2019: Foreword, Program and Abstracts

The 16th Meeting of the Interuniversity Institute of Myology (IIM), October 17-20, 2019, Assisi, Italy brought together scientists, pharma and patient organization representatives discussing new results on muscle research. Internationally renowned Keynote speakers presented advances on muscle development, homeostasis, metabolism, and disease. Speakers selected among submitted abstracts presented their new, unpublished data in seven scientific sessions. The remaining abstracts were showcased in two poster sessions. Young trainees where directly involved in the selection of keynote speakers, the organizing scientific sessions and roundtables discussions tailored to the interests of their peers. A broad Italian, European and North-American audience participated to the different initiatives. The meeting allowed muscle biology researchers to discuss ideas and scientific collaborations aimed at better understanding the mechanisms underlying muscle diseases in order to develop better therapeutic strategies. The active participation of young trainees was facilitated by the friendly and inclusive atmosphere, which fostered lively discussions identifying emerging areas of myology research and stimulated scientific cross-fertilization. The meeting was a success and the IIM community will continue to bring forward significant contributions to the understanding of muscle development and function, the pathogenesis of muscular diseases and the development of novel therapeutic approaches. Here, we report abstracts of the meeting illustrating novel results of basic, translational, and clinical research, which confirms that the Myology field is strong and healthy.

Resistance Exercise, Electrical Muscle Stimulation, and Whole-Body Vibration in Older Adults: Systematic Review and Meta-Analysis of Randomized Controlled Trials

It has been shown that resistance exercise (RT) is one of the most effective approaches to counteract the physical and functional changes associated with aging. This systematic review with meta-analysis compared the effects of RT, whole-body vibration (WBV), and electrical muscle stimulation (EMS) on muscle strength, body composition, and functional performance in older adults. A thorough literature review was conducted, and the analyses were limited to randomized controlled trials. In total, 63 studies were included in the meta-analysis (48 RT, 11 WBV, and 4 EMS). The results showed that RT and WBV are comparably effective for improving muscle strength, while the effects of EMS remains debated. RT interventions also improved some outcome measures related to functional performance, as well as the cross-sectional area of the quadriceps. Muscle mass was not significantly affected by RT. A limitation of the review is the smaller number of WBV and particularly EMS studies. For this reason, the effects of WBV and EMS could not be comprehensively compared to the effect of RT for all outcome measures. For the moment, RT or combinations of RT and WBV or EMS, is probably the most reliable way to improve muscle strength and functional performance, while the best approach to increase muscle mass in older adults remains open to further studies.

Muscle Hypertrophy and Architectural Changes in Response to Eight-Week Neuromuscular Electrical Stimulation Training in Healthy Older People

Loss of muscle mass of the lower limbs and of the spine extensors markedly impairs locomotor ability and spine stability in old age. In this study, we investigated whether 8 w of neuromuscular electrical stimulation (NMES) improves size and architecture of the lumbar multifidus (LM) and vastus lateralis (VL) along with locomotor ability in healthy older individuals. Eight volunteers (aged 65 ≥ years) performed NMES 3 times/week. Eight sex- and age-matched individuals served as controls. Functional tests (Timed Up and Go test (TUG) and Five Times Sit-to-Stand Test (FTSST)), VL muscle architecture (muscle thickness (MT), pennation angle (PA), and fiber length (FL)), along with VL cross-sectional area (CSA) and both sides of LM were measured before and after by ultrasound. By the end of the training period, MT and CSA of VL increased by 8.6% and 11.4%, respectively. No significant increases were observed in FL and PA. LM CSA increased by 5.6% (left) and 7.1% (right). Interestingly, all VL architectural parameters significantly decreased in the control group. The combined NMES had a large significant effect on TUG (r = 0.50, p = 0.046). These results extend previous findings on the hypertrophic effects of NMES training, suggesting to be a useful mean for combating age-related sarcopenia.

Home-Based Functional Electrical Stimulation of Human Permanent Denervated Muscles: A Narrative Review on Diagnostics, Managements, Results and Byproducts Revisited 2020

Spinal cord injury (SCI) produces muscle wasting that is especially severe after complete and permanent damage of lower motor neurons, as can occur in complete conus and cauda equina syndrome. Even in this worst-case scenario, mass and function of permanently denervated quadriceps muscle can be rescued by surface functional electrical stimulation using a purpose designed home-based rehabilitation strategy. Early diagnostics is a key factor in the long-term success of this management. Function of quadriceps muscle was quantitated by force measurements. Muscle gross cross-sections were evaluated by quantitative color computed tomography (CT) and muscle and skin biopsies by quantitative histology, electron microscopy, and immunohistochemistry. Two years of treatment that started earlier than 5 years from SCI produced: (a) an increase in cross-sectional area of stimulated muscles; (b) an increase in muscle fiber mean diameter; (c) improvements in ultrastructural organization; and (d) increased force output during electrical stimulation. Improvements are extended to hamstring muscles and skin. Indeed, the cushioning effect provided by recovered tissues is a major clinical benefit. It is our hope that new trials start soon, providing patients the benefits they need.

MicroRNAs in Sarcopenia: A Systematic Review

Sarcopenia, which is characterized by the loss of skeletal muscle, has been reported to contribute to development of physical disabilities, various illnesses, and increasing mortality. MicroRNAs (miRNAs) are small non-coding RNAs that inhibit translation of target messenger RNAs. Previous studies have shown that miRNAs play pivotal roles in the development of sarcopenia. Therefore, this systematic review focuses on miRNAs that regulate sarcopenia.

MicroRNAs in Skeletal Muscle Aging: Current Issues and Perspectives

Skeletal muscle is one of the major organs responsible for body movements and metabolism making up approximately 40% of the total body mass. During aging, skeletal muscle exhibits a degenerative age-associated decline in mass and function termed sarcopenia. This age-associated dysfunction of skeletal muscle is a major criterion of morbidity, mortality, and overall declines of quality of life in the elderly people. Therefore, researchers have focused on identifying modulators of muscle aging process including messenger RNAs, proteins, and recently small noncoding RNAs such as microRNAs (miRNAs). In particular, miRNAs have been demonstrated to play a critical role in skeletal muscle development and homeostasis. Recent studies revealed that miRNAs were also involved in muscle aging processes and the rejuvenation of aged muscle by regulating important molecules and pathways of aging including insulin-like growth factors, nicotine-adenine dinucleotide (+)-dependent protein deacetylase sirtuin-1, telomerase reverse transcriptase, and transforming growth factor-β signaling pathway. Over the years, miRNAs have emerged as promising candidates for biomarkers of sarcopenia and targets for interventions to slow muscle aging. Here, we comprehensively review the current knowledge on the role of miRNAs in skeletal muscle aging and highlight their potential as biomarkers or therapeutic targets for skeletal muscle health.

Thirty years of translational research in Mobility Medicine: Collection of abstracts of the 2020 Padua Muscle Days

More than half a century of skeletal muscle research is continuing at Padua University (Italy) under the auspices of the Interdepartmental Research Centre of Myology (CIR-Myo), the European Journal of Translational Myology (EJTM) and recently also with the support of the A&CM-C Foundation for Translational Myology, Padova, Italy. The Volume 30(1), 2020 of the EJTM opens with the collection of abstracts for the conference "2020 Padua Muscle Days: Mobility Medicine 30 years of Translational Research". This is an international conference that will be held between March 18-21, 2020 in Euganei Hills and Padova in Italy. The abstracts are excellent examples of translational research and of the multidimensional approaches that are needed to classify and manage (in both the acute and chronic phases) diseases of Mobility that span from neurologic, metabolic and traumatic syndromes to the biological process of aging. One of the typical aim of Physical Medicine and Rehabilitation is indeed to reduce pain and increase mobility enough to enable impaired persons to walk freely, garden, and drive again. The excellent contents of this Collection of Abstracts reflect the high scientific caliber of researchers and clinicians who are eager to present their results at the PaduaMuscleDays. A series of EJTM Communications will also add to this preliminary evidence.

Machine learning predictive system based upon radiodensitometric distributions from mid-thigh CT images

The nonlinear trimodal regression analysis (NTRA) method based on radiodensitometric CT images distributions was developed for the quantitative characterization of soft tissue changes according to the lower extremity function of elderly subjects. In this regard, the NTRA method defines 11 subject-specific soft tissue parameters and has illustrated high sensitivity to changes in skeletal muscle form and function. The present work further explores the use of these 11 NTRA parameters in the construction of a machine learning (ML) system to predict body mass index and isometric leg strength using tree-based regression algorithms. Results obtained from these models demonstrate that when using an ML approach, these soft tissue features have a significant predictive value for these physiological parameters. These results further support the use of NTRA-based ML predictive assessment and support the future investigation of other physiological parameters and comorbidities.

Timed synchronization of muscle contraction to heartbeat enhances muscle hyperemia

Blood flow (BF) to exercising muscles is susceptible to variations of intensity, and duration of skeletal muscle contractions, cardiac cycle, blood velocity, and vessel dilation. During cyclic muscle activity, these elements may change proportionally with or without direct optimal temporal alignment, likely influencing BF to active muscle. Ideally, the pulsed delivery of blood to active muscle timed with the inactive phase of muscle duty-cycle would enhance the peak and average BF. To investigate the phenomenon of muscle contraction and pulse synchronicity, electrically evoked muscle contractions (trains of 20 Hz, 200-ms duration) were synchronized with each systolic phase of the anterograde blood velocity spectrum (aBVS). Specifically, unilateral quadriceps contractions matched in-phase (IP) with the aBVS were compared with contractions matched out-of-phase (OP) with the aBVS in 10 healthy participants (26 ± 3 yr). During each trial, femoral BF of the contracting limb and central hemodynamics were recorded for 5 min with an ultrasound Doppler, a plethysmograph, and a cardioimpedance device. At steady state (5th min) IP BF (454 ± 30 mL/min) and vascular conductance (4.3 ± 0.2 mL·min^-1·mmHg^-1), and OP MAP (108 ± 2 mmHg) were significantly lower (P < 0.001) in comparison to OP BF (784 ± 25 mL/min) and vascular conductance (6.7 ± 0.2 mL·min^-1·mmHg^-1), and IP MAP (113 ± 3 mmHg). On the contrary, no significant difference (all, P > 0.05) was observed between IP and OP central hemodynamics (HR: 79 ± 10 vs. 76 ± 11 bpm, CO: 8.0 ± 1.6 vs. 7.3 ± 1.6 L/min), and ventilatory patterns (V̇e:14 ± 2 vs. 14 ± 1 L/min, V̇o₂:421 ± 70 vs. 397 ± 34 mL/min). The results suggest that muscle contractions occurring during OP that do not interfere with aBVS elicit a maximization of muscle functional hyperemia.NEW & NOTEWORTHY When muscle contraction is synchronized with the pulsed delivery of blood flow to active muscle, muscle functional hyperemia can be either maximized or minimized. This suggests a possibility to couple different strategies to enhance the acute and chronic effects of exercise on the cardiovascular system.

Cancer cachexia, a clinical challenge

PURPOSE OF REVIEW

The aim of this article is to review the metabolic background of the cachectic syndrome and to analyze the recent therapeutic approaches designed to counteract the wasting suffered by the cancer patient with cachexia.

RECENT FINDINGS

The main changes associated with the development of this multiorganic syndrome are glucose intolerance, fat depletion and muscle protein hypercatabolism. Among the most promising approaches for the treatment of cachexia include the use of ghrelin agonists, beta-blockers, beta-adrenergic agonists, androgen receptor agonists and antimyostatin peptides. The multitargeted approach seems essential in these treatments, which should include the combination of both nutritional support, drugs and a suitable program of physical exercise, in order to ameliorate both anorexia and the metabolic changes associated with cachexia. In addition, another very important aspect for the design of clinical trials for the treatment of cancer cachexia is to staging cancer patients in relation with the degree of cachexia, in order to start as early as possible, this triple approach in the course of the disease, even before weight loss can be detected.

SUMMARY

Cancer cachexia has two main components: anorexia and metabolic alterations and both have to be taken into consideration for the treatment of the syndrome.

Assessing cardiovascular risks from a mid-thigh CT image: a tree-based machine learning approach using radiodensitometric distributions

The nonlinear trimodal regression analysis (NTRA) method based on radiodensitometric CT distributions was recently developed and assessed for the quantification of lower extremity function and nutritional parameters in aging subjects. However, the use of the NTRA method for building predictive models of cardiovascular health was not explored; in this regard, the present study reports the use of NTRA parameters for classifying elderly subjects with coronary heart disease (CHD), cardiovascular disease (CVD), and chronic heart failure (CHF) using multivariate logistic regression and three tree-based machine learning (ML) algorithms. Results from each model were assembled as a typology of four classification metrics: total classification score, classification by tissue type, tissue-based feature importance, and classification by age. The predictive utility of this method was modelled using CHF incidence data. ML models employing the random forests algorithm yielded the highest classification performance for all analyses, and overall classification scores for all three conditions were excellent: CHD (AUCROC: 0.936); CVD (AUCROC: 0.914); CHF (AUCROC: 0.994). Longitudinal assessment for modelling the prediction of CHF incidence was likewise robust (AUCROC: 0.993). The present work introduces a substantial step forward in the construction of non-invasive, standardizable tools for associating adipose, loose connective, and lean tissue changes with cardiovascular health outcomes in elderly individuals.

Two-years of home based functional electrical stimulation recovers epidermis from atrophy and flattening after years of complete Conus-Cauda Syndrome

To evaluate progression of skin atrophy during 8 years of complete Conus-Cauda Syndrome and its recovery after 2 years of surface Functional Electrical Stimulation a cohort study was organized and implemented.Functional assessments, tissue biopsies, and follow-up were performed at the Wilhelminenspital, Vienna, Austria; skin histology and immunohistochemistry at the University of Padova, Italy on 13 spinal cord injury persons suffering up to 10 years of complete conus/cauda syndrome. Skin biopsies (n. 52) of both legs were analyzed before and after 2 years of home-based Functional Electrical Stimulation delivered by large anatomically shaped surface electrodes placed on the skin of the anterior thigh. Using quantitative histology we analyzed: 1. Epidermis atrophy by thickness and by area; 2. Skin flattening by computing papillae per mm and Interdigitation Index of dermal-epidermal junctions; 3. Presence of Langerhans cells.Linear regression analyses show that epidermal atrophy and flattening worsen with increasing years post- spinal cord injury and that 2 years of skin electrostimulation by large anatomically shaped electrodes reverses skin changes (pre-functional Electrical Stimulation vs post-functional Electrical Stimulation: thickness 39%, P < .0001; area 41%, P < .0001; papillae n/mm 35%, P < 0.0014; Interdigitation index 11%, P < 0.018), producing a significant recovery to almost normal levels of epidermis thickness and of dermal papillae, with minor changes of Langerhans cells, despite 2 additional years of complete Conus-Cauda Syndrome.In complete Conus-Cauda Syndrome patients, the well documented beneficial effects of 2 years of surface h-b Functional Electrical Stimulation on strength, bulk, and muscle fiber size of thigh muscles are extended to skin, suggesting that electrical stimulation by anatomically shaped electrodes fixed to the skin is also clinically relevant to counteract atrophy and flattening of the stimulated skin. Mechanisms, pros and cons are discussed.

Neuromuscular Electrical Stimulation Induces Skeletal Muscle Fiber Remodeling and Specific Gene Expression Profile in Healthy Elderly

Skeletal muscle aging is a multifactorial process strictly related to progressive weakness. One of the results that were focused on was the fiber phenotype modification and their loss. The physiological muscle recruitment to contraction, basically prosecuted under volitional control, can also be engaged by means of Neuromuscular Electrical Stimulation (NMES). Knowing that the NMES is effective in improving muscle strength in active healthy elderly, the aim was to investigate which physiological modifications were able to produce in the Vastus lateralis muscle and the pathways involved. It was found that NMES increased the cross sectional area and the isometric strength of type II myofibers together with the activated myogenic pathway in order to shift glycolytic toward the oxidative phenotype II myofibers, at a molecular level and with an increase of maximal voluntary contraction (MVC) at a functional level. Using the TaqMan low density array on 48 different genes, we found that NMES specific gene regulation highlighted: (i) increased protein synthesis with respect to protein degradation; (ii) the activation of an apoptotic pathway involved in the differentiation process; (iii) increased regeneration signals; (iv) oxidative enzyme regulation. These pathways were validated via confirmatory RT-PCR for genes involved in the regeneration process as well as Myosin isoforms. We also investigated the oxidative stress status analyzing superoxide anion levels, the protein expression of two different superoxide dismutase and the activity of both catalase and superoxide anion dismutase, being two main antioxidant enzymes. In conclusion, data demonstrates that NMES is effective in producing physiological adaptation on Vastus Lateralis of active healthy elderly as well as providing new insights for further research on elderly who experienced muscle detriment for periodic or permanent immobility.

Presbyphagia Diagnostics Using M-Mode Ultrasound: Changes in the Tongue Movement Pattern

Age-related physiological changes of the swallowing act impair particularly the oral phase and the tongue function, which is very important for bolus preparation and transfer. At present, there are no easily applicable methods for measurement of this phase of swallowing. This study was designed to investigate the deglutitive tongue movement by M-mode ultrasound and to compare the collected parameters of different age groups. In this exploratory prospective study, the tongue and its movements of 20 younger and 30 older women were examined during swallowing by B-mode and M-mode ultrasound. Preexisting dysphagia or malnutrition as well as psychic or neurological deficits were excluded by clinical examination and screening with the Mini Nutritional Assessment-Short Form (MNA-SF), the Gugging Swallowing Screen (GUSS), the Mini-Mental State Examination (MMSE) and the Barthel Index. The data were compared with each other and statistically analyzed. With increasing age, a change in the tongue movement pattern becomes apparent. In the group of older women, the vertical lingual movement had a smaller amplitude (p < 0.001) and a shorter time to the maximum amplitude (p < 0.03) than in the group of younger women. However, there were no differences in the tongue diameter (p > 0.4). The tongue movement pattern appears to be subject to age-specific changes, in contrast to anatomy. The use of M-mode ultrasonography is an easy, radiation-free and cost-effective method for the assessment of the oral phase of swallowing. Limitations are the widely scattered values of the ultrasound findings. Further studies are needed for validation and definition of standard values for this promising method.

Functional genomics applications and therapeutic implications in sarcopenia

The human genome contains around 20,000-25,000 genes coding for 30,000 proteins. Some proteins and genes represent therapeutic targets for human diseases. RNA and protein expression profiling tools allow the study of the molecular basis of aging and drug discovery validation. Throughout the life, there is an age-related and disease-related muscle decline. Sarcopenia is defined as a loss of muscle mass and a decrease in functional properties such as muscle strength and physical performance. Yet, there is still no consensus on the evaluation methods of sarcopenia prognosis. The main challenge of this complex biological phenomena is its multifactorial etiology. Thus, functional genomics methods attempt to shape the related scientific approaches via an innovative in-depth view on sarcopenia. Gene and drug high throughput screening combined with functional genomics allow the generation and the interpretation of a large amount of data related to sarcopenia and therapeutic progress. This review focuses on the application of selected functional genomics techniques such as RNA interference, RNA silencing, proteomics, transgenic mice, metabolomics, genomics, and epigenomics to better understand sarcopenia mechanisms.

Regulatory mechanisms and clinical manifestations of musculoskeletal aging

Aging is the strongest risk factor for degenerative bone and joint diseases. Clinical therapies for age-related musculoskeletal disorders face significant challenges as their pathogenic mechanisms remain largely unclear. This review article focuses on the recent advances in the understanding of regulatory mechanisms of musculoskeletal aging and their clinical relevance. We begin with the prevalence and socioeconomic impacts of major age-related musculoskeletal disorders such as sarcopenia, osteoporosis, osteoarthritis, and degenerative tendinopathy. The current understanding of responsible biological mechanisms involved in general aging is then summarized. Proposed molecular, cellular, and biomechanical mechanisms relevant to the clinical manifestations of aging in the musculoskeletal system are discussed in detail, with a focus on the disorders affecting muscle, bone, articular cartilage, and tendon. Although musculoskeletal aging processes share many common pathways with the aging of other body systems, unique molecular and cellular mechanisms may be involved in the aging processes of musculoskeletal tissues. Advancements in the understanding of regulatory mechanisms of musculoskeletal aging may promote the development of novel treatments for age-related musculoskeletal disorders. Finally, future research directions for major musculoskeletal tissues including functional interaction between the tissues and their clinical relevance to age-related musculoskeletal disorders are highlighted in the Future Prospects section. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1475-1488, 2019.

Age-dependent variations in the expression of myosin isoforms and myogenic factors during the involution of the proximal sesamoidean ligament of sheep

In ungulates the stability of the fetlock joint is dependent on several muscles, which are exposed to high stress and strain. Among those muscles, the proximal sesamoidean ligament or PSL (also known as the suspensory ligament or Ruini's elasto-tendinous organ) is organized at birth in layers of muscle fibres alternated with abundant tendinous tissue that, during the postnatal development, becomes the predominant tissue. In this study we analysed the PSL of the sheep at the age of 1, 30 and 180 days and determined the expression of several genes which either (a) are markers of muscle fibre growth and maturation, or (b) play a role as signal molecules. We observed an accelerated maturation, as indicated by the transition of MyHC isoform expression towards the slow isoforms and a reduced regenerative potential indicated by the low Pax7 expression and the altered Wnt signalling. We also found a specific myogenic expression pattern of MyoD, Myf5 and Myogenin in the developing PSL and high mRNA levels of specific fibrogenic factors, as TGF-β1, that, undoubtedly, stimulate the growth of connective tissue. Our observations confirmed, at molecular level, the peculiarity of the fast involution observed in PSL a muscle that undergoes a very specific active differentiation process during early development, which implies myofibres involution and their replacement with connective tissue.

Therapeutic strategies against cancer cachexia

Cancer cachexia has two main components: anorexia and metabolic alterations. The main changes associated with the development of this multi-organic syndrome are glucose intolerance, fat depletion and muscle protein hypercatabolism. The aim of this paper is to review the more recent therapeutic approaches designed to counteract the wasting suffered by the cancer patient with cachexia. Among the most promising approaches we can include the use of ghrelin agonists, beta-blockers, beta-adrenergic agonists, androgen receptor agonists and anti-myostatin peptides. The multi-targeted approach seems essential in these treatments, which should include the combination of both nutritional support, drugs and a suitable program of physical exercise, in order to ameliorate both anorexia and the metabolic changes associated with cachexia. In addition, another very important and crucial aspect to be taken into consideration in the design of clinical trials for the treatment of cancer cachexia is to staging cancer patients in relation with the degree of cachexia, in order to start as early as possible this triple approach in the course of the disease, even before the weight loss can be detected.

Angiotensin-Converting Enzyme Inhibitor Use and Incident Frailty: A Longitudinal Cohort Study

INTRODUCTION

Angiotensin-converting enzyme inhibitors (ACEI) may have several pleiotropic effects, but the literature regarding a possible relationship between ACEI use and frailty is limited. We investigated whether ACEI use is associated with lower risk of frailty in a cohort of North American individuals.

METHODS

Data from the Osteoarthritis Initiative, a cohort study with 8 years of follow-up including community-dwelling adults with knee osteoarthritis or at high risk for this condition, were analyzed. ACEI use was defined through self-reported information and confirmed by a trained interviewer. Frailty was defined using the Study of Osteoporotic Fracture (SOF) index as the presence of at least two of the following criteria: (1) weight loss ≥ 5% between baseline and any subsequent follow-up visit; (2) inability to do five chair stands; and (3) low energy level according to the SOF definition. A multivariable Poisson regression analysis was used to assess the association between ACEI use at baseline and incident frailty. The data were reported as relative risks (RRs) with their 95% confidence intervals (CIs).

RESULTS

The final sample consisted of 4295 adults (mean age 61.2 years, females 58.1%). At baseline, 551 participants (12.8%) used ACEI. After adjusting for 15 potential confounders, the use of ACEI was associated with a lower risk of frailty (RR 0.72; 95% CI 0.53-0.99). The adjustment for the propensity score substantially confirmed these findings (RR 0.75; 95% CI 0.54-0.996).

CONCLUSION

ACEI use may be associated with a reduced risk of frailty in individuals with/at risk of knee osteoarthritis, suggesting a potential role for ACI in the prevention of frailty.

2019Spring PaduaMuscleDays: Translational Myology and Mobility Medicine

A half-century tradition of skeletal muscles studies, started with a research on fever, is continuing under the auspices of the Interdepartmental Research Centre of Myology (CIR-Myo), Department of Biomedical Sciences, University of Padova, Italy, the A&C M-C Foundation for Translational Myology, Padova, Italy and the European Journal of Translational Myology (EJTM). This year an EJTM Special will be dedicated to Muscle Fascia, an under looked topic, which merits more attention. Furthermore, this year the 2019SpringPaduaMuscleDays: Translational Myology and Mobility Medicine, an International Conference, was held March 28-30, 2019 in Euganei Hills and Padova (Italy). The abstracts of the 2019SpPMD, that are reported in the Myology News of EJTM 29(1), 2019, are excellent examples of translational research. Their excellent contents are at the level needed for approval by Ethical Committees, International Granting Agencies, and Editors of international journals, thanks to the high scientific profiles of researchers and clinicians who are eager to present their results at the PaduaMuscleDays.

Dermal papillae flattening of thigh skin in Conus Cauda Syndrome

Our previous studies have shown that severely atrophic Quadriceps muscles of spinal cord injury (SCI) persons suffering with complete conus and cauda equina syndrome, and thus with permanent denervation-induced atrophy and degeneration of muscle, were almost completely rescued to normal size after two years of home based Functional Electrical Stimulation (hbFES). Since large surface electrodes were used to stimulate the denervated thigh muscles, we wanted to know if the skin was affected by this peculiar long-term treatment. Indeed, we demonstrated by two approaches that the epidermis decreases in thickness in the long term denervated persons, while it increased to almost pre-SCI values in hbFES compliant SCI persons. Here we report data of morphometry of skin biopsies from both legs of 18 SCI persons, harvested at enrolment in the Project RISE, to test if the Interdigitation Index, a simple measurement of the epidermal-dermal junction, may provide a further precise quantitative evidence of the flattening of the skin in those SCI persons. The Interdigitation Index of the 36 skin biopsies shows a higly significant linear correlation with the years of SCI (p < 0.001). Furthermore, when the 18 SCI persons are divided in two groups (1 to 3.9 versus 4.1 to 8.0 years from SCI, respectively) and the data are compared, the later Group presents a statistically significant -22% decrease (p, 0.029) of the Interdigitation Index. On the other hand counting the papille do not provide the same strong evidence. In conclusion, the Interdigitation Index is an additional sound quantitative structural biomarker of skin atrophy and flattening occurring in SCI. The result correlates with the much severe extent of atrophy of the permanently denervated thigh muscles, as determined at both macro and microscopic levels.We are confident that the Interdigitation Index will provide sound evidence that the effects of hbFES, we previously reported on skeletal muscle and epidermis thickness, will be extended to the dermal layer of the skin, suggesting a coordinated negative effects of SCI on skeletal muscle and skin, and an improvement of both tissues after hbFES. Incoming analyses will be extended to basal lamina, collagene types, elastic fibers and skin annexes in the subcutaneous layer.

Muscle spindles of the rat sternomastoid muscle

The sternomastoid (SM) muscle in rodents presents a peculiar distribution of fiber types with a steep gradient from the ventral, superficial, white portion to the dorsal, deep, red region, where muscle spindles are restricted. Cross section of the medial longitudinal third of the rat SM contains around 10,000 muscle fibers with a mean diameter of 51.28±12.62 (μm +/- SD). Transverse sections stained by Succinate Dehydrogenase (SDH) reaction clearly presents two distinct regions: the dorsal deep red portion encompassing a 40% cross section area contains a high percentage of packed SDH-positive muscle fibers, and the ventral superficial region which contains mainly SDH-negative muscle fibers. Indeed, the ventral superficial region of the rat SM muscle contains mainly fast 2B muscle fibers. These acidic ATPase pH 4.3-negative and SDH-negative 2B muscle fibers are the largest of the SM muscle, while the acidic ATPase pH 4.3-positive and SDH-positive Type 1 muscle fibers are the smallest. Here we show that in thin transverse cryosections only 2 or 3 muscle spindle are observed in the central part of the dorsal deep red portion of the SM muscle. Azan Mallory stained sections allow at the same time to count the spindles and to evaluate aging fibrosis of the skeletal muscle tissue. Though restricted in the muscle red region, SM spindles are embedded in perimysium, whose changes may influence their reflex activity. Our findings confirm that any comparisons of changes in number and percentage of muscle spindles and muscle fibers of the rat SM muscle will require morphometry of the whole muscle cross-section. Muscle biopsies of SM muscle from large mammals will only provide partial data on the size of the different types of muscle fibers biased by sampling. Nonetheless, histology of muscle tissue continue to provide practical and low-cost quantitative data to follow-up translational studies in rodents and beyond.

Myokines in Home-Based Functional Electrical Stimulation-Induced Recovery of Skeletal Muscle in Elderly and Permanent Denervation

Neuromuscular disorders, disuse, inadequate nutrition, metabolic diseases, cancer and aging produce muscle atrophy and this implies that there are different types of molecular triggers and signaling pathways for muscle wasting. Exercise and muscle contractions may counteract muscle atrophy by releasing a group of peptides, termed myokines, to protect the functionality and to enhance the exercise capacity of skeletal muscle. In this review, we are looking at the role of myokines in the recovery of permanent denervated and elderly skeletal muscle tissue. Since sub-clinical denervation events contribute to both atrophy and the decreased contractile speed of aged muscle, we saw a parallel to spinal cord injury and decided to look at both groups together. The muscle from lifelong active seniors has more muscle bulk and more slow fiber-type groupings than those of sedentary seniors, demonstrating that physical activity maintains slow motoneurons that reinnervate the transiently denervated muscle fibers. Furthermore, we summarized the evidence that muscle degeneration occur with irreversible Conus and Cauda Equina syndrome, a spinal cord injury in which the human leg muscles may be permanently disconnected from the peripheral nervous system. In these patients, suffering with an estreme case of muscle disuse, a complete loss of muscle fibers occurs within five to ten years after injury. Their recovered tetanic contractility, induced by home-based Functional Electrical Stimulation, can restore the muscle size and function in compliant Spinal Cord Injury patients, allowing them to perform electrical stimulation-supported stand-up training. Myokines are produced and released by muscle fibers under contraction and exert both local and systemic effects. Changes in patterns of myokine secretion, particularly of IGF-1 isoforms, occur in long-term Spinal Cord Injury persons and also in very aged people. Their modulation in Spinal Cord Injury and late aging are also key factors of home-based Functional Electrical Stimulation - mediated muscle recovery. Thus, Functional Electrical Stimulation should be prescribed in critical care units and nursing facilities, if persons are unable or reluctant to exercise. This will result in less frequent hospitalizations and a reduced burden on patients' families and public health services.

Muscle plasticity of aged subjects in response to electrical stimulation training and inversion and/or limitation of the sarcopenic process

This review addresses the possible structural and functional adaptations of the muscle function to neuromuscular electrical stimulation (NMES) training in frail and/or aged (without advanced chronic disease) subjects. Evidence suggests that the sarcopenic process and its structural and functional effects would be limited and/or reversed through NMES training using excito-motor currents (or direct currents). From a structural viewpoint, NMES helps reduce muscle atrophy. From a functional viewpoint, NMES enables the improvement of motor output (i.e., muscle strength), gait, balance and activities of daily living which enhances the quality of life of aged subjects. Muscle plasticity of aged subjects in response to NMES training turns out to be undeniable, although many mechanisms are not yet explained and deserve to be explore further. Mechanistic explanations as well as conceptual models are proposed to explain how muscle plasticity operates in aged subjects through NMES training. NMES could be seen as a clinically applicable training technique, safe and efficient among aged subjects and could be used more often as part of prevention of sarcopenia. Therapists and physical conditioners/trainers could exploit this new knowledge in their professional practice to improve life conditions (including the risk of fall) of frail and/or aged subjects.

EJTM3 is also covering Mobility and Medicine at large, an update

Since the first 2018 issue, the European Journal of Translational Myology expanded its authorship and readership from the strict topics of biology, physiology, diagnostic, management and rehabilitation of skeletal muscle to the more clinically relevant fields of human mobility to those of general medicine. This third issue opens with a review on Chronic Fatigue Syndrome, a very complex medical problem, as its other names testify (Myalgic Encephalomyelitis or Systemic Exertion Intolerance Disease). A more typical molecular myology original article follows (Increasing autophagy does not affect neurogenic muscle atrophy), but then several Rapid Reports cover different Medical Specialties fields, related or unrelated to neuromyology, mobility problems and their potential solutions. The Advisors of EJTM invite Authors to submit typescripts, taking into account that the journal is keen to publish high-level papers in the fields of Translational Myology, Mobility and Medicine at large.

Old muscle in young body: an aphorism describing the Chronic Fatigue Syndrome

The chronic fatigue syndrome (CFS) otherwise known as myalgic encephalomyelitis (ME), is a debilitating syndrome whose identification is very complex due to lack of precise diagnostic criteria. This pathology begins with limitations in duration and intensity of exercise and rapid onset of pain during physical activity. Its etiology is unknown, and symptoms are not limited to the muscles. Epidemiology is rather difficult to delimit, even if it affects mainly young (20-40 years), female subjects. The results of muscular research show some peculiarities that can justify what has been observed in vivo. In particular, 1. presence of oxidative damage of lipid component of biological membranes and DNA not compensated by the increase of the scavenger activity; 2. Excitation-Contraction (E-C) alteration with modification of Ca2+ transport; 3. passage from slow to fast fiber phenotype; 4. inability to increase glucose uptake; 5. presence of mitochondrial dysfunction; and 6. genes expressed differentially (particularly those involved in energy production). The skeletal muscles of CFS / ME patients show a significant alteration of the oxidative balance due to mitochondrial alteration and of the fiber phenotype composition as shown in sarcopenic muscles of the elderly. Vice versa, the muscle catabolism does not appear to be involved in the onset of this syndrome. The data support the hypothesis that patients with CFS are subjected to some of the problems typical for muscle aging, which is probably related to disorders of muscle protein synthesis and biogenesis of mitochondria. Patients with CFS can benefit from an appropriate training program because no evidence suggests that physical exercise worsens symptoms. Type, intensity and duration of any physical activity that activates muscle contraction (including Electrical Stimulation) require further investigation even if it is known that non-exhaustive physical activity decreases painful symptomatology.

Muscle and skin improve by home-based FES and full-body in-bed gym

All progressive muscle contractile impairments, including advanced age-related muscle power decline, need permanent management. Most elderly persons, in particular octogenarians, spend small amounts of time in daily physical activity, resulting in a decline in body condition with more and more frequent hospitalizations and finally potentially forcing them to bed permanently. Further several neurological injuries, which are even more acutely debilitating than those problems related to aging, are responsible for early limitation of mobility. Inspired by the proven capability to recover skeletal muscle contractility and strength by home-based functional electrical stimulation (h-bFES) in both elderly and SCI patients, we suggest that the elderly and early aging patients participate in hbFES and add a 20 min daily routine of 12 easy and safe physical exercises, namely home-based Full-Body In-Bed Gym. Continued regularly, h-bFES and the Full-Body In-Bed Gym will help to maintain the independence of frail older people and may reduce the risks of serious consequences of accidental falls and pressure sore complications.

Chemotherapy-induced muscle wasting: an update

The majority of cancers are associated to cachexia, a severe form of weight loss mostly accounted for by skeletal muscle wasting. Cancer patients are often treated with chemotherapy, whose side effects are at times neglected or underestimated. Paradoxically, chemotherapy itself can induce muscle wasting with severe, cancer-independent effects on muscle homeostasis. Since muscle wasting is a primary marker of poor prognosis for cancer patients and negatively affects their quality of life, the systemic consequences of chemotherapy in this context must be fully characterized and taken into account. Ten years ago a precursor study in an animal cancer model was published in the European Journal of Translation Myology (back then, Basic and Applied Myology), highlighting that the side effects of chemotherapy include muscle wasting, possibly mediated by NF-κB activation. This paper, entitled «Chemotherapy-induced muscle wasting: association with NF-κB and cancer cachexia», is now being reprinted for the inaugural issue of the «Ejtm Seminal Paper Series». In this short review we discuss those results in the light of the most recent advances in the study of chemotherapy-induced muscle wasting.

From Ejtm (European Journal of Translational Myology) to Ejt3M (European Journal of Translational Myology, Mobility, Medicine)

This first 2018 Issue of the European Journal of Translational Myology presents many novelties, that are demonstrating that the journal is vital and expanding its authorship, readership and relevance from focused fields of biology, physiology, diagnostic, management and rehabilitation of skeletal muscle tissue to the more interesting and clinical relevant fields of human mobility up to those of general medicine. The Editorial Board is consequently expanded to allow fair and expert evaluation of more broadly interests and expertise of the Authors submitting typescripts. We are considering the option to move the name of the journal from Ejtm to Ejt3M (Myology, Mobility, Medicine). Criticisms and suggestions are welcomed.