Renin-angiotensin system: an old player with novel functions in skeletal muscle

Predictive Value of Ultrasound-Measured Quadriceps Depth and Frailty Status for Hypotension in Older Patients Undergoing Reverse Total Shoulder Arthroplasty in the Beach Chair Position under General Anesthesia

The beach chair position (BCP) is widely used in shoulder surgery; however, it frequently leads to hypotension. Hypotension in BCP is prevalent among older patients who are at risk of secondary complications such as ischemic injuries. Therefore, this prospective study aimed to investigate the association and predictive value of frailty, as assessed by ultrasound-measured quadriceps depth and questionnaire, in patients aged ≥65 years undergoing elective shoulder surgery under general anesthesia. A multivariable logistic regression analysis was performed to identify independent risk factors for hypotension in BCP under general anesthesia. Receiver operating characteristic curves were constructed to assess the predictive values of various parameters. The results indicated that a quadriceps depth < 2.3 cm and BCP for an extended period significantly increased the risk of hypotension. The combined consideration of quadriceps depth < 2.3 cm and frailty demonstrated markedly superior predictive power compared with each factor individually. In conclusion, the study findings facilitate the screening and identification of risk factors for older patients undergoing surgery in BCP, thereby enhancing perioperative management.

The Effect of Antihypertensive Therapy on Skeletal Muscle Mass and Bone Mineral Density in Patients With End-Stage Kidney Disease

OBJECTIVE

Sarcopenia and osteoporosis substantially influence health and lifespan. However, the variables affecting skeletal muscle mass (SMM) or bone mineral density (BMD) remain unknown.

DESIGN AND METHODS

From August 1, 2018 to July 31, 2019, we conducted a single-center, observational cohort study with 291 Japanese adult patients on maintenance hemodialysis due to end-stage kidney disease, who had their femoral neck BMD measured using dual-energy X-ray absorptiometry. After 1-year follow-up, we measured annual changes of BMD (ΔBMD) and SMM (ΔSMM), which were calculated through a modified creatinine index (mg/kg/day) using age, sex, serum creatinine, and single-pooled Kt/V for urea. The factors associated with ΔSMM/ΔBMD or progressive loss of SMM/BMD, defined as ΔSMM/ΔBMD < 0 per year, respectively, were analyzed with multivariable, linear regression or logistic regression models.

RESULTS

The median age of the patients was 66 years and 33% were female. Dialysis vintage and β-blocker-use were inversely correlated to ΔSMM. In comparison to nonusers, β-blockers users had 2.5-fold higher SMM loss odd ratios [95% confidence interval, 1.3-4.8]. The risk for SMM loss caused by β-blockers was not increased in users of renin-angiotensin system inhibitors. The ΔBMD was negatively correlated to the usage of calcium channel blockers. The risk of developing osteosarcopenia, which was defined as annual loss of both SMM and BMD, increased in calcium channel blockers users.

CONCLUSIONS

The use of β-blockers is associated with an elevated risk of developing sarcopenia, whereas renin-angiotensin system inhibitors may minimize this effect in patients with end-stage kidney disease. Use of calcium channel blocker therapy was associated with a faster decline of BMD.

The Current Landscape of Pharmacotherapies for Sarcopenia

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

Independent Link Between Use of Mineralocorticoid Receptor Antagonists and Muscle Wasting in Heart Failure Patients Not Receiving Renin-Angiotensin System Inhibitors

BACKGROUND

The renin-angiotensin system (RAS) activation is a proposed mechanism of muscle wasting (MW i.e., reduction in muscle mass). Although we reported that RAS inhibitors (RASIs) were associated with lower prevalence of MW in heart failure (HF) patients, the relationship between mineralocorticoid receptor (MR) signaling and MW has not been analyzed.Methods and Results: We analyzed data from 320 consecutive Japanese HF patients who underwent dual-energy X-ray absorptiometry scanning for assessment of appendicular skeletal muscle mass index (ASMI). In multiple linear regression analyses, plasma renin activity (PRA) was negatively correlated with ASMI in patients not receiving RASIs, indicating an untoward role of the RAS in MW. Results of analysis of covariance in which risk factors of MW served as covariates showed that use of MR antagonists (MRAs) was associated with lower ASMI and higher PRA in the non-RASIs group. The close relationship between use of MRAs and lower ASMI or higher PRA in the non-RASIs group was confirmed in analyses in which the differences in baseline characteristics between users and non-users of MRAs were minimized by using an inverse probability of treatment weighting.

CONCLUSIONS

Increased PRA by MR inhibition without concurrent RAS inhibition, possibly contributing to upregulation of angiotensin II signaling, may be associated with reduction in muscle mass.

Anti-SRP immune-mediated necrotizing myopathy responsive to ofatumumab: a case report

Background

Immune-mediated necrotizing myopathies (IMNM) is a rare disease that was first described in 2004. Due to the lack of large case series, there are no formal treatment recommendations for IMNM.

Methods

We presented a case of a 47-year-old woman who experienced progressive limb weakness, starting from the lower limbs and gradually affecting the upper limbs. She also reported experiencing dyspnea after engaging in daily activities. When she was admitted to the hospital, her upper limbs were almost unable to move and she could not stand even with support. Her Creatine kinase (CK) level significantly increased (> 3500 u/l). Electromyography showed myogenic damage, anti-Signal recognition particle (anti-SRP) and anti-Ro52 antibodies were highly positive. Pathological biopsy of the right biceps muscle showed necrotizing myopathy in the skeletal muscle. She was ultimately diagnosed with anti-SRP IMNN, and was given monotherapy with methylprednisolone and combination therapy with immunoglobulin, but her symptoms continued to worsen. The patient refused to bear the possible further liver dysfunction and blood system damage caused by Cyclophosphamide and Rituximab, and she chose to try to use Ofatumumab (OFA).

Results

After receiving three doses of OFA treatment without any adverse reactions, she reported that her muscle strength had basically recovered and she was able to walk independently. The B cells in the circulatory system have been depleted, and blood markers such as liver function have consistently remained within normal range. During the follow up, her activity tolerance continued to improve.

Discussion

We have presented a severe case of SRP-IMNM in which the patient showed poor response to conventional immunotherapy. However, rapid symptom relief was achieved with early sequential use of OFA treatment. This provides a new option for the treatment of SRP-IMNM, and more large-scale studies will be needed in the future to verify our results.

Angiotensin-(1-7) improves skeletal muscle regeneration

Skeletal muscle possesses regenerative potential via satellite cells, compromised in muscular dystrophies leading to fibrosis and fat infiltration. Angiotensin II (Ang-II) is commonly associated with pathological states. In contrast, Angiotensin (1-7) [Ang-(1-7)] counters Ang-II, acting via the Mas receptor. While Ang-II affects skeletal muscle regeneration, the influence of Ang-(1-7) remains to be elucidated. Therefore, this study aims to investigate the role of Ang-(1-7) in skeletal muscle regeneration. C2C12 cells were differentiated in the absence or presence of 10 nM of Ang-(1-7). The diameter of myotubes and protein levels of myogenin and myosin heavy chain (MHC) were determined. C57BL/6 WT male mice 16-18 weeks old) were randomly assigned to injury-vehicle, injury-Ang-(1-7), and control groups. Ang-(1-7) was administered via osmotic pumps, and muscle injury was induced by injecting barium chloride to assess muscle regeneration through histological analyses. Moreover, embryonic myosin (eMHC) and myogenin protein levels were evaluated. C2C12 myotubes incubated with Ang-(1-7) showed larger diameters than the untreated group and increased myogenin and MHC protein levels during differentiation. Ang-(1-7) administration enhances regeneration by promoting a larger diameter of new muscle fibers. Furthermore, higher numbers of eMHC (+) fibers were observed in the injured-Ang-(1-7), which also had a larger diameter. Moreover, eMHC and myogenin protein levels were elevated, supporting enhanced regeneration due to Ang-(1-7) administration. Ang-(1-7) effectively promotes differentiation in vitroand improves muscle regeneration in the context of injuries, with potential implications for treating muscle-related disorders.

Pathophysiology of sarcopenia: Genetic factors and their interplay with environmental factors

Sarcopenia is a geriatric disorder characterized by a progressive decline in muscle mass and function. This disorder has been associated with a range of adverse health outcomes, including fractures, functional deterioration, and increased mortality. The pathophysiology of sarcopenia is highly complex and multifactorial, involving both genetic and environmental factors as key contributors. This review consolidates current knowledge on the genetic factors influencing the pathogenesis of sarcopenia, particularly focusing on the altered gene expression of structural and metabolic proteins, growth factors, hormones, and inflammatory cytokines. While the influence of environmental factors such as physical inactivity, chronic diseases, smoking, alcohol consumption, and sleep disturbances on sarcopenia is relatively well understood, there is a dearth of studies examining their mechanistic roles. Therefore, this review emphasizes the interplay between genetic and environmental factors, elucidating their cumulative role in exacerbating the progression of sarcopenia beyond their individual effects. The unique contribution of this review lies in synthesizing the latest evidence on the genetic factors and their interaction with environmental factors, aiming to inform the development of novel therapeutic or preventive interventions for sarcopenia.

Effect of physical activity on long COVID fatigue: an unsolved enigma

Covid-19 disease is well documented and often the most common symptoms include myalgia and muscle fatigue. Approximately 10% of those infected complain of persistent fatigue even many months after the end of the acute phase of the disease. This gives rise to a condition different from the previous one and commonly known as 'post-acute COVID-19 syndrome' or simply Long-COVID. Although the origin of muscle fatigue is multifactorial, the state of prolonged fatigue observed in the Long-COVID syndrome suggests the existence of a possible state of atrophy or rather acute sarcopenia. Under these conditions, the use of physical activity programs can effectively counteract the state of atrophy underlying the fatigue phenomena observed. If this is also the situation during the Long-COVID, the muscular symptom should be positively influenced by the administration of programmed physical activity cycles. In fact, in patients with Long-COVID, the few published papers seem to indicate that patients who are physically active and who make an effort to engage in physical activity even during the illness have decreased duration and intensity of the illness. However, analysis of the studies in the literature also suggests that a small percentage of people with Long-COVID do not appear to benefit from the application of physical activity programs, so further studies on homogeneous samples are needed to provide a firm answer to the question: can planned physical activity help patients during the pathological course of Long-COVID?

Musculoskeletal pain post-COVID-19 in patients undergoing physical therapy in Saudi Arabia: a cross-sectional study

BACKGROUND

The COVID-19 (coronavirus disease 2019) pandemic has posed a challenge to the physical therapy service. In addition to pandemic-associated treatment interference, many recovered COVID-19 patients developed new or worsening musculoskeletal pain as a sequela of COVID-19, which has been shown to affect the musculoskeletal system. The objective of the study was to examine musculoskeletal pain post-COVID-19 in patients undergoing physical therapy in Saudi Arabia.

METHODS

The design of the study was a cross-sectional study. We approached patients attending physical therapy clinics who had COVID-19. Data were collected through an electronic survey consisting of multiple-choice questions related to sociodemographic data and pain. Pain severity was rated on a 10-point numerical rating scale.

RESULTS

A total of 85 recovered COVID-19 patients participated in this study, 30 had musculoskeletal pain prior to getting COVID-19, while 55 acquired it after. The most affected sites for musculoskeletal pain were the lower back and shoulder. Mean pain levels reported increased from 4.48 ± 2.54 pre-COVID-19 to 6.92 ± 8.06 post-COVID-19 (mean difference, 1.61 ± 2.61; t = 5.68; p < 0.0001). Mean pain scores did not associate significantly with demographic or clinical factors. Patient responses skewed toward increased pain as well as decreased activity levels after being infected with COVID-19 versus pre-COVID-19 (all p < 0.0001).

CONCLUSIONS

Recovered COVID-19 patients reported increased pain intensity and frequency, together with reduced activity levels, relative to pre-COVID-19 levels, without effects of sociodemographic or clinical characteristics.

Novel Potential Targets for Function-Promoting Therapies: Orphan Nuclear Receptors, Anti-inflammatory Drugs, Troponin Activators, Mas Receptor Agonists, and Urolithin A

In recent years, several new classes of therapies have been investigated with their potential for restoring or improving physical functioning in older adults. These have included Mas receptor agonists, regulators of mitophagy, skeletal muscle troponin activators, anti-inflammatory compounds, and targets of orphan nuclear receptors. The present article summarizes recent developments of the function-promoting effects of these exciting new compounds and shares relevant preclinical and clinical data related to their safety and efficacy. The development of novel compounds in this area is expanding and likely will need the advent of a new treatment paradigm for age-associated mobility loss and disability.

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

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

Neurological Manifestations of Coronavirus Disease 2019 in Hospitalized Patients: A Lebanese Cohort Study

BACKGROUND

Concerns regarding potential neurologic complications of COVID-19 are being increasingly reported worldwide. Our objective was to investigate the neurologic complications of COVID-19 among a cohort of Lebanese patients with SARS-CoV-2 infection admitted to Rafik Hariri University Hospital (RHUH), the leading COVID-19 testing and treatment center in Lebanon.

METHODS

This is a retrospective, single-center, observational study conducted from March to July 2020 at RHUH, Lebanon.

RESULTS

Of 169 hospitalized patients with confirmed SARS-CoV-2 infection (mean {SD} age was 45.75 {19} years and 62.7% were men), 91 patients (53.8%) had severe infection and 78 patients (46.2%) had non-severe infection according to the American Thoracic Society guidelines for community-acquired pneumonia. Overall, 112 patients (66.3%) developed neurologic symptoms: CNS (46.1%), PNS (43.7%), and skeletal muscle injury (2.4%). Compared with patients with non-severe infection, patients with severe infection were significantly older, were male and more likely to have underlying disorders, especially diabetes and cardiac or cerebrovascular disease. Moreover, those patients experienced more typical COVID-19 symptoms at onset of illness such as fever, cough and fatigue. However, there was no significant difference in the frequency of all nervous system manifestations between the severe and the non-severe infection groups (57 {62.6%} vs 55 {70.5%}; p =0.316), except for impaired consciousness, where seven patients had impaired consciousness in the severe group compared to none in the non-severe group (p=0.012).

CONCLUSION

A wide variety of neurologic symptoms were detected in our Lebanese cohort of hospitalized COVID-19 patients. A comprehensive knowledge of the neurologic manifestations will help healthcare providers to be more attentive to these complications.

Is the anti-aging effect of ACE2 due to its role in the renin-angiotensin system?-Findings from a comparison of the aging phenotypes of ACE2-deficient, Tsukuba hypertensive, and Mas-deficient mice

Angiotensin converting enzyme 2 (ACE2) functions as an enzyme that produces angiotensin 1-7 (A1-7) from angiotensin II (AII) in the renin-angiotensin system (RAS). We evaluated aging phenotypes, especially skeletal muscle aging, in ACE2 systemically deficient (ACE2 KO) mice and found that ACE2 has an antiaging function. The characteristic aging phenotype observed in ACE2 KO mice was not reproduced in mice deficient in the A1-7 receptor Mas or in Tsukuba hypertensive mice, a model of chronic AII overproduction, suggesting that ACE2 has a RAS-independent antiaging function. In this review, the results we have obtained and related studies on the aging regulatory mechanism mediated by RAS components will be presented and summarized. We evaluated the aging phenotype of ACE2 systemically deficient (ACE2 KO) mice, particularly skeletal muscle aging, and found that ACE2 has an antiaging function. The characteristic aging phenotype observed in ACE2 KO mice was not reproduced in Mas KO mice, angiotensin 1-7 receptor-deficient mice or in Tsukuba hypertensive mice, a model of chronic angiotensin II overproduction, suggesting that the antiaging functions of ACE2 are independent of the renin-angiotensin system (RAS).

SARcopenia Assessment in Hypertension: The SARAH Study

OBJECTIVES

The aims of the study were to investigate the relationship between sarcopenia and renin-angiotensin system-related disorders and to explore the effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on muscle mass/function and physical performance.

DESIGN

This multicenter, cross-sectional study was performed using ISarcoPRM algorithm for the diagnosis of sarcopenia.

RESULTS

Of the 2613 participants (mean age = 61.0 ± 9.5 yrs), 1775 (67.9%) were hypertensive. All sarcopenia-related parameters (except chair stand test in males) were worse in hypertensive group than in normotensive group (all P < 0.05). When clinical/potential confounders were adjusted, hypertension was found to be an independent predictor of sarcopenia in males (odds ratio = 2.403 [95% confidence interval = 1.514-3.813]) and females (odds ratio = 1.906 [95% confidence interval = 1.328-2.734], both P < 0.001). After adjusting for confounding factors, we found that all sarcopenia-related parameters (except grip strength and chair stand test in males) were independently/negatively related to hypertension (all P < 0.05). In females, angiotensin-converting enzyme inhibitors users had higher grip strength and chair stand test performance values but had lower anterior thigh muscle thickness and gait speed values, as compared with those using angiotensin II receptor blockers (all P < 0.05).

CONCLUSIONS

Hypertension was associated with increased risk of sarcopenia at least 2 times. Among antihypertensives, while angiotensin-converting enzyme inhibitors had higher muscle function values, angiotensin II receptor blockers had higher muscle mass and physical performance values only in females.

Mini-review: Angiotensin- converting enzyme 1 (ACE1) and the impact for diseases such as Alzheimer's disease, sarcopenia, cancer, and COVID-19

Ageing has been associated with comorbidities, systemic low-grade of inflammation, and immunosenescence. Hypertension is the most common morbidity and anti-hypertensives are used for more than 50%. Angiotensin-converting enzyme 1 inhibitors (ACEi) and angiotensin II receptor blockers (ARB) control blood pressure but also seem to play a role in comorbidities such as Alzheimer's disease, sarcopenia and cancer. The impact of anti-hypertensives in comorbidities is due to the expression of renin-angiotensin system (RAS) in several tissues and body fluids. Angiotensin-converting enzyme 1 (ACE1) has been linked to oxidative stress, metabolism, and inflammation. The levels and activity of ACE1 are under genetic control and polymorphisms have been correlated with susceptibility to Alzheimer's disease. In addition, some results found that ACEi and ARB users present delayed cognitive decline and reduced risk of dementia. Regarding to sarcopenia, RAS has been linked to the catabolic and anabolic pathways for muscle mass maintenance. In some studies, older adults using ACEi were highly benefited by exercise training. In cancer, RAS and its products have been shown to play a role since their inhibition in animal models modulates tumor microenvironment and improves the delivery of chemotherapy drugs. Clinically, the incidence of colorectal cancer is reduced in patients using ACEi and ARB. During the pandemic COVID-19 it was found that ACE2 receptor plays a role in the entry of SARS-CoV-2 into the host cell. ACE1 genotypes have been linked to an increased risk for COVID-19 and severe disease. In some studies COVID-19 patients taking ARB or ACEi presented better outcome.

Molecular and cellular mechanisms involved in tissue-specific metabolic modulation by SARS-CoV-2

Coronavirus disease 2019 (COVID-19) is triggered by the SARS-CoV-2, which is able to infect and cause dysfunction not only in lungs, but also in multiple organs, including central nervous system, skeletal muscle, kidneys, heart, liver, and intestine. Several metabolic disturbances are associated with cell damage or tissue injury, but the mechanisms involved are not yet fully elucidated. Some potential mechanisms involved in the COVID-19-induced tissue dysfunction are proposed, such as: (a) High expression and levels of proinflammatory cytokines, including TNF-α IL-6, IL-1β, INF-α and INF-β, increasing the systemic and tissue inflammatory state; (b) Induction of oxidative stress due to redox imbalance, resulting in cell injury or death induced by elevated production of reactive oxygen species; and (c) Deregulation of the renin-angiotensin-aldosterone system, exacerbating the inflammatory and oxidative stress responses. In this review, we discuss the main metabolic disturbances observed in different target tissues of SARS-CoV-2 and the potential mechanisms involved in these changes associated with the tissue dysfunction.

Lifting the Mask on Musculoskeletal Manifestations of COVID-19: Results of an Interview-Based Study

Background

Coronavirus disease of 2019 (COVID-19) is considered a multi-system disease that might present with or develop complications during the acute phase of illness. The aim of this study was to describe the characteristics of musculoskeletal (MSK) manifestations in patients with COVID-19 infection and investigate their clinical correlations.

Methods

This study was carried out on 110 patients with a history of RT-PCR confirmed COVID-19 infection. They completed a questionnaire that covered detailed information on their sociodemographic characteristics, clinical data of COVID-19 infection in addition to MSK discomfort form based on the Nordic MSK Questionnaire.

Results

The mean age of the patients was 37.7 years (SD 12.9), 72.7% were females. The majority of patients (90.9%) reported MSK symptoms that occur during or shortly after the acute attack of COVID-19 infection. The median duration of onset of MSK symptoms was 2 days from the first day of COVID-19 infection (min-max: 0–45 days) with a median duration of MSK symptoms of 7 days. Myalgia was the main complaint (85.5%) followed by arthralgia 90 (81.8%). However, swollen joints were reported in only 9 patients (8.2%). According to the body areas, maximum number of patients felt pain at the lower back (60%), followed by neck (39.1%), and upper back (32.5%) followed by right and left shoulder (20.9%). Patients with MSK manifestations were associated higher severity of COVID-19 infection (p < 0.001), prolonged duration of COVID-19 symptoms (p < 0.001) and higher prevalence of fatigue (p < 0.001).

Conclusion

MSK manifestations are common in COVID-19 patients and related to disease severity, duration and fatigue.

Exercise Induced-Cytokines Response in Marathon Runners: Role of ACE I/D and BDKRB2 +9/-9 Polymorphisms

Renin-angiotensin system (RAS) and kallikrein-kinin system (KKS) have a different site of interaction and modulate vascular tone and inflammatory response as well on exercise adaptation, which is modulated by exercise-induced cytokines. The aim of the study was to evaluate the role of ACE I/D and BDKRB2 +9/−9 polymorphism on exercise-induced cytokine response. Seventy-four male marathon finishers, aged 30 to 55 years, participated in this study. Plasma levels of exercise-induced cytokines were determined 24 h before, immediately after, and 24 h and 72 h after the São Paulo International Marathon. Plasma concentrations of MCP-1, IL-6 and FGF-21 increased after marathon in all genotypes of BDKRB2. IL-10, FSTL and BDNF increased significantly after marathon in the genotypes with the presence of the −9 allele. FSTL and BDNF concentrations were higher in the −9/−9 genotype compared to the +9/+9 genotype before (p = 0.006) and after the race (p = 0.023), respectively. Apelin, IL-15, musclin and myostatin concentrations were significantly reduced after the race only in the presence of −9 allele. Marathon increased plasma concentrations of MCP1, IL-6, BDNF and FGF-21 in all genotypes of ACE I/D polymorphism. Plasma concentrations of IL-8 and MIP-1alpha before the race (p = 0.015 and p = 0.031, respectively), of MIP-1alpha and IL-10 after the race (p = 0.033 and p = 0.047, respectively) and VEGF 72 h after the race (p = 0.018) were lower in II homozygotes compared to runners with the presence of D allele. One day after the race we also observed lower levels of MIP-1alpha in runners with II homozygotes compared to DD homozygotes (p = 0.026). Before the marathon race myostatin concentrations were higher in DD compared to II genotypes (p = 0.009). Myostatin, musclin, IL-15, IL-6 and apelin levels decreased after race in genotypes with the presence of D allele. After the race ACE activity was negatively correlated with MCP1 (r = −56, p < 0.016) and positively correlated with IL-8, IL-10 and MIP1-alpha (r = 0.72, p < 0.0007, r = 0.72, p < 0.0007, r = 0.47, p < 0.048, respectively). The runners with the −9/−9 genotype have greater response in exercise-induced cytokines related to muscle repair and cardioprotection indicating that BDKRB2 participate on exercise adaptations and runners with DD genotype have greater inflammatory response as well as ACE activity was positively correlated with inflammatory mediators. DD homozygotes also had higher myostatin levels which modulates protein homeostasis.

Nervous system manifestations related to COVID-19 and their possible mechanisms

In December 2019, the novel coronavirus disease (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection broke. With the gradual deepening understanding of SARS-CoV-2 and COVID-19, researchers and clinicians noticed that this disease is closely related to the nervous system and has complex effects on the central nervous system (CNS) and peripheral nervous system (PNS). In this review, we summarize the effects and mechanisms of SARS-CoV-2 on the nervous system, including the pathways of invasion, direct and indirect effects, and associated neuropsychiatric diseases, to deepen our knowledge and understanding of the relationship between COVID-19 and the nervous system.

Effect of nebivolol on altered skeletal and cardiac muscles induced by dyslipidemia in rats: impact on oxidative and inflammatory machineries

AIM

High cholesterol diet is greatly linked to deleterious health consequences. In this work we tried to explore direct effects of high cholesterol diet on striated (skeletal and cardiac) muscle tissues and the mechanisms by which nebivolol could improve such harmful effects.

METHODS

The study included 24 healthy adult male albino rats weighing 200-220 grams that were assigned into four groups: control group, control drug group, high cholesterol diet fed groups; one untreated the other was treated with nebivolol.

RESULTS

In the cholesterol fed group, we found decreased blood HDL and NO with elevated total cholesterol, triglycerides, myoglobin, CK, LDH, ALP, in addition to elevated muscle tissue levels of HIF-1, NF-kB, MDA, and decreased expression of both eNOS, reduced GSH. Wire hanging test time was shorter in the high cholesterol group than control group rats, which was confirmed histologically by increased striated muscle fibre thickness and cytochrome area %. Nebivolol treatment ameliorated the effects of high cholesterol diet.

CONCLUSION

High cholesterol diet caused myopathic changes in rat striated muscle tissues mostly due to oxidative stress associated with enhanced NF-kB and HIF-1 expression. Nebivolol appears beneficial in the management of hypercholesterolaemia-induced striated muscle injury.

Genome-Wide Analysis in Drosophila Reveals the Genetic Basis of Variation in Age-Specific Physical Performance and Response to ACE Inhibition

Despite impressive results in restoring physical performance in rodent models, treatment with renin–angiotensin system (RAS) inhibitors, such as Lisinopril, have highly mixed results in humans, likely, in part, due to genetic variation in human populations. To date, the genetic determinants of responses to drugs, such as RAS inhibitors, remain unknown. Given the complexity of the relationship between physical traits and genetic background, genomic studies which predict genotype- and age-specific responses to drug treatments in humans or vertebrate animals are difficult. Here, using 126 genetically distinct lines of Drosophila melanogaster, we tested the effects of Lisinopril on age-specific climbing speed and endurance. Our data show that functional response and sensitivity to Lisinopril treatment ranges from significant protection against physical decline to increased weakness depending on genotype and age. Furthermore, genome-wide analyses led to identification of evolutionarily conserved genes in the WNT signaling pathway as being significantly associated with variations in physical performance traits and sensitivity to Lisinopril treatment. Genetic knockdown of genes in the WNT signaling pathway, Axin, frizzled, nemo, and wingless, diminished or abolished the effects of Lisinopril treatment on climbing speed traits. Our results implicate these genes as contributors to the genotype- and age-specific effects of Lisinopril treatment and because they have orthologs in humans, they are potential therapeutic targets for improvement of resiliency. Our approach should be widely applicable for identifying genomic variants that predict age- and sex-dependent responses to any type of pharmaceutical treatment.

Vitamin D/Vitamin D Receptor Signaling Attenuates Skeletal Muscle Atrophy by Suppressing Renin-Angiotensin System

The nutritional level of vitamin D may affect musculoskeletal health. We have reported that vitamin D is a pivotal protector against tissue injuries by suppressing local renin-angiotensin system (RAS). This study aimed to explore the role of the vitamin D receptor (VDR) in the protection against muscle atrophy and the underlying mechanism. A cross-sectional study on participants (n = 1034) in Shanghai (China) was performed to analyze the association between vitamin D level and the risk of low muscle strength as well as to detect the circulating level of angiotensin II (Ang II). In animal studies, dexamethasone (Dex) was applied to induce muscle atrophy in wild-type (WT) and VDR-null mice, and the mice with the induction of muscle atrophy were treated with calcitriol for 10 days. The skeletal muscle cell line C2C12 and the muscle satellite cells were applied in in vitro studies. The increased risk of low muscle strength was correlated to a lower level of vitamin D (adjusted odds ratio [OR] 0.58) accompanied by an elevation in serum Ang II level. Ang II impaired the myogenic differentiation of C2C12 myoblasts as illustrated by the decrease in the area of myotubes and the downregulation of myogenic factors (myosin heavy chain [MHC] and myogenic differentiation factor D [MyoD]). The phenotype of muscle atrophy induced by Dex and Ang II was aggravated by VDR ablation in mice and in muscle satellite cells, respectively, and mediated by RAS and its downstream phosphatidylinositol 3-kinase/protein kinase B/forkhead box O1 (PI3K/Akt/FOXO1) signaling. Calcitriol treatment exhibited beneficial effects on muscle function as demonstrated by the increased weight-loaded swimming time, grip strength, and fiber area, and improved fiber type composition via regulating ubiquitin ligases and their substrates MHC and MyoD through suppressing renin/Ang II axis. Taken together, VDR protects against skeletal muscle atrophy by suppressing RAS. Vitamin D could be a potential agent for the prevention and treatment of skeletal muscle atrophy. © 2021 American Society for Bone and Mineral Research (ASBMR).

Combined Administration of Andrographolide and Angiotensin- (1-7) Synergically Increases the Muscle Function and Strength in Aged Mice

BACKGROUND

Sarcopenia is a progressive and generalized skeletal muscle disorder characterized by muscle weakness, loss of muscle mass, and decline in the capacity of force generation. Aging can cause sarcopenia. Several therapeutic strategies have been evaluated to prevent or alleviate this disorder. One of them is angiotensin 1-7 [Ang-(1-7)], an anti-atrophic peptide for skeletal muscles that regulates decreased muscle mass for several causes, including aging. Another regulator of muscle mass and function is andrographolide, a bicyclic diterpenoid lactone that decreases the nuclear factor kappa B (NF-κB) signaling and attenuates the severity of some muscle diseases.

OBJECTIVE

Evaluate the effect of combined administration of Ang-(1-7) with andrographolide on the physical performance, muscle strength, and fiber´s diameter in a murine model of sarcopenia by aging.

METHODS

Aged male mice of the C57BL/6J strain were treated with Andrographolide, Ang-(1-7), or combined for three months. The physical performance, muscle strength, and fiber´s diameter were measured.

RESULTS

The results showed that aged mice (24 months old) treated with Ang-(1-7) or Andrographolide improved their performance on a treadmill test, muscle strength, and their fiber´s diameter compared to aged mice without treatment. The combined administration of Ang-(1-7) with andrographolide to aged mice has an enhanced synergically effect on physical performance, muscle strength, and fiber´s diameter.

CONCLUSION

Our results indicated that in aged mice, the effects of andrographolide and Ang-(1-7) on muscle function, strength, and fiber´s diameter are potentiated.

Muscle-bone axis in children with chronic kidney disease: current knowledge and future perspectives

Bone and muscle tissue are developed hand-in-hand during childhood and adolescence and interact through mechanical loads and biochemical pathways forming the musculoskeletal system. Chronic kidney disease (CKD) is widely considered as both a bone and muscle-weakening disease, eventually leading to frailty phenotype, with detrimental effects on overall morbidity. CKD also interferes in the biomechanical communication between two tissues. Pathogenetic mechanisms including systemic inflammation, anorexia, physical inactivity, vitamin D deficiency and secondary hyperparathyroidism, metabolic acidosis, impaired growth hormone/insulin growth factor 1 axis, insulin resistance, and activation of renin-angiotensin system are incriminated for longitudinal uncoordinated loss of bone mineral content, bone strength, muscle mass, and muscle strength, leading to mechanical impairment of the functional muscle-bone unit. At the same time, CKD may also interfere in the biochemical crosstalk between the two organs, through inhibiting or stimulating the expression of certain osteokines and myokines. This review focuses on presenting current knowledge, according to in vitro, in vivo, and clinical studies, concerning the pathogenetic pathways involved in the muscle-bone axis, and suggests approaches aimed at preventing bone loss and muscle wasting in the pediatric population. Novel therapeutic targets for preserving musculoskeletal health in the context of CKD are also discussed.

Neurological complications and infection mechanism of SARS-COV-2

Currently, SARS-CoV-2 has caused a global pandemic and threatened many lives. Although SARS-CoV-2 mainly causes respiratory diseases, growing data indicate that SARS-CoV-2 can also invade the central nervous system (CNS) and peripheral nervous system (PNS) causing multiple neurological diseases, such as encephalitis, encephalopathy, Guillain-Barré syndrome, meningitis, and skeletal muscular symptoms. Despite the increasing incidences of clinical neurological complications of SARS-CoV-2, the precise neuroinvasion mechanisms of SARS-CoV-2 have not been fully established. In this review, we primarily describe the clinical neurological complications associated with SARS-CoV-2 and discuss the potential mechanisms through which SARS-CoV-2 invades the brain based on the current evidence. Finally, we summarize the experimental models were used to study SARS-CoV-2 neuroinvasion. These data form the basis for studies on the significance of SARS-CoV-2 infection in the brain.

Angiotensin II inhibition: a potential treatment to slow the progression of sarcopenia

Sarcopenia is defined as the progressive and generalized loss of skeletal muscle mass and strength, which is associated with increased likelihood of adverse outcomes including falls, fractures, physical disability, and mortality. The etiology of sarcopenia has been postulated to be multifactorial with genetics, aging, immobility, nutritional deficiencies, inflammation, stress, and endocrine factors all contributing to the imbalance of muscle anabolism and catabolism. The prevalence of sarcopenia is estimated to range from 13 to 24% in adults over 60 years of age and up to 50% in persons aged 80 and older. As the population continues to age, the prevalence of sarcopenia continues to increase and is expected to affect 500 million people by the year 2050. Sarcopenia impacts the overall health of patients through limitations in functional status, increase in hospital readmissions, poorer hospital outcomes, and increase in overall mortality. Thus, there exists a need to prevent or reduce the occurrence of sarcopenia. Here, we explore the potential mechanisms and current studies regarding angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors on reducing the development of sarcopenia through the associated changes in cardiovascular function, renal function, muscle fiber composition, inflammation, endothelial dysfunction, metabolic efficiency, and mitochondrial function.

The Critical Role of Oxidative Stress in Sarcopenic Obesity

Sarcopenic obesity (SO) is a combination of obesity and sarcopenia that primarily develops in older people. Patients with SO have high fat mass, low muscle mass, low muscle strength, and low physical function. SO relates to metabolic syndrome and an increased risk of morbimortality. The prevalence of SO varies because of lacking consensus criteria regarding its definition and the methodological difficulty in diagnosing sarcopenia and obesity. SO includes systemic alterations such as insulin resistance, increased proinflammatory cytokines, age-associated hormonal changes, and decreased physical activity at pathophysiological levels. Interestingly, these alterations are influenced by oxidative stress, which is a critical factor in altering muscle function and the generation of metabolic dysfunctions. Thus, oxidative stress in SO alters muscle mass, the signaling pathways that control it, satellite cell functions, and mitochondrial and endoplasmic reticulum activities. Considering this background, our objectives in this review are to describe SO as a highly prevalent condition and look at the role of oxidative stress in SO pathophysiology.

Dieckol Reduces Muscle Atrophy by Modulating Angiotensin Type II Type 1 Receptor and NADPH Oxidase in Spontaneously Hypertensive Rats

The renin-angiotensin system is involved in the development of hypertension and sarcopenia. Increased levels of angiotensin II (Ang II) lead to upregulation of Ang II type 1 receptor (AT1R), which results in increasing reactive oxygen species (ROS) by NAD(P)H oxidase (Nox). Increased ROS led to increased helper T17 (Th17) and decreased regulatory T (Treg) cells through HIF-1α. Increased Th17 secretes more IL-17, leading to increased NF-κB and muscle atrophy. We evaluated the effect of Ecklonia cava extracts (ECE) and dieckol (DK) on attenuating muscle atrophy by decreasing AT1R and NOX activity in spontaneous hypertensive rats (SHRs). The serum levels of Ang II and expression of AT1R in the muscle were higher in SHRs than in normotensive animals of Wistar-Kyoto rats (2.4 and 1.8 times higher than WKY, respectively). The expression of AT1R decreased by ECE or DK (0.62 and 0.84 times lower than SHR, respectively). In SHRs, the expression of Nox 1, 2, and 4 were increased (1.2-1.15 times higher than WKY) but were decreased by the administration of ECE (0.8-0.9 times lower than SHR) or DK (0.7-0.9 times lower than SHR). The Nox activity was increased in SHRs (2.3 times more than WKY) and it was decreased by ECE (0.9 times lower than SHRs) and DK (0.9 times lower than SHRs). The expression of HIF-1α, a marker of Th17 (RORγt), and cytokine secreted by Th17 (IL-17) was increased in SHRs and was decreased by ECE or DK. The marker of Treg (Foxp3) and cytokine secreted from Treg cells (IL-10) was decreased in SHRs and was increased by ECE or DK. The expression of NF-κB/IL-1β/TNF-α and MuRF-1/MAFbx/atrogin-1 was increased in SHRs and these were decreased by ECE or DK. The cross-sectional area of muscle fiber was decreased in SHRs (0.7 times lower than WKY) and was increased by ECE (1.3 times greater than SHR) or DK (1.5 times greater than SHR). In conclusion, ECE or DK leads to a decreased expression of AT1R and Nox activity which modulates Th17/Treg balance and consequently, decreased muscle atrophy.

Ang-(1-7) protects skeletal muscle function in aged mice

Background

The angiotensin-converting enzyme 2 (ACE2)/angiotensin 1–7 (Ang-(1–7)) axis has been shown to protect against the age-associated decline in skeletal muscle function. Here, we investigated the protective effects of ACE2 in mitigating the age-associated decline of skeletal muscle function and to identify the potential underlying molecular mechanisms.

Methods

We measured the expression levels of Ang-(1–7) in C57BL/6J mice of different ages and correlated these levels with measures of skeletal muscle function. We also investigated the expression of myocyte enhancer factor 2 A (MEF2A) in ACE2 knockout (ACE2KO) mice and its relationship with muscle function. We then treated aged ACE2KO mice for four weeks with Ang-(1–7) and characterized the levels of MEF2A and skeletal muscle function before and after treatment. We assessed the impact of Ang-(1–7) on the growth and differentiation of C2C12 cells in vitro and assessed changes in expression of the glucose transporter type 4 (Glut4).

Results

Aged mice showed reduced skeletal muscle function and levels of Ang-(1–7) expression in comparison to young and middle-aged mice. In ACE2KO mice, skeletal muscle function and MEF2A protein expression were significantly lower than in age-matched wild-type (WT) mice. After one month of Ang-(1–7) treatment, skeletal muscle function in the aged ACE2KO mice improved, while MEF2A protein expression was similar to that in the untreated group. In C2C12 cells, Ang-(1–7) was shown to promote along with the upregulated expression of Glut4.

Conclusions

The ACE2/ Ang-(1–7) axis has a protective function in skeletal muscle and administration of exogenous Ang-(1–7) can delay the age-related decline in the function of skeletal muscle.

Rewinding sarcopenia: a narrative review on the renin-angiotensin system

BACKGROUND AND AIMS

The purpose of this review was two-fold. First, we aimed to provide an in-depth glance on the relationship between renin-angiotensin system (RAS) dysregulation and sarcopenia. Second, we aimed to touch upon potential treatments of sarcopenia (including RAS blockers, vitamin D, and exercise) in light of the pertinent literature.

METHODS

Currently available research regarding the effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers on knee extensor strength, grip strength, chair stand test, gate speed together with the effects of exercise on muscle mass, strength, physical performance, blood pressure and cognitive tests (particularly in older adults) was reviewed.

RESULTS

Although some studies have shown favorable effects of ACEIs on muscle strength and/or physical function tests, some studies have reported no/negative association in between. The favorable impact of exercise on reducing blood pressure is shown, and exercise treatment is widely recommended in the relevant literature. Different types of exercises (aerobic, resistance, dancing, music movement, water-based, golf, knitting activities or multicomponent exercises) have shown improvement in cognitive functions as well.

CONCLUSION

Classical RAS activity results in deleterious effects not only on the cardiovascular but also on the neuromusculoskeletal system. Therefore, treatments targeting inhibition of the classical RAS activity seem to be important in the management of several age-related pathologies, including sarcopenia. As such, ACEIs, vitamin D, exercise, and healthy diet can have prominent effects not only on the modulation of RAS but also on physical and cognitive functions and sarcopenia as well.

What can the neurological manifestations of COVID-19 tell us: a meta-analysis

Background

Covid-19 became a global pandemic in 2019. Studies have shown that coronavirus can cause neurological symptoms, but clinical studies on its neurological symptoms are limited. In this meta-analysis, we aimed to summarize the various neurological manifestations that occurred in COVID-19 patients and calculate the incidence of various neurological manifestations. At the same time, we further explored the mechanism of nervous system injury and prognosis in COVID-19 patients in combination with their nervous system manifestations. This study provides a reference for early clinical identification of COVID-19 nervous system injury in the future, so as to achieve early treatment and reduce neurological sequelae.

Methods

We systematically searched all published English literature related to the neurological manifestations of COVID-19 from January 1, 2020, to April 30, 2021, in Pubmed, Embase, and Cochrane Library. The keywords used were COVID-19 and terminology related to the nervous system performance. All included studies were selected by two independent reviewers using EndNote and NoteExpress software, any disagreement was resolved by consensus or by a third reviewer, and the selected data were then collected for meta-analysis using a random-effects model.

Results

A total of 168 articles (n = 292,693) were included in the study, and the meta-analysis showed that the most common neurological manifestations of COVID-19 were myalgia(33%; 95%CI 0.30–0.37; I² = 99.17%), smell impairment(33%; 95%CI 0.28–0.38; I² = 99.40%), taste dysfunction(33%; 95%CI 0.27–0.39; I² = 99.09%), altered mental status(32%; 95%CI 0.22–0.43; I² = 99.06%), headache(29%; 95%CI 0.25–0.33; I² = 99.42%), encephalopathy(26%; 95%CI 0.16–0.38; I² = 99.31%), alteration of consciousness(13%; 95%CI 0.08–0.19; I² = 98.10%), stroke(12%; 95%CI 0.08–0.16; I² = 98.95%), dizziness(10%; 95%CI 0.08–0.13; I² = 96.45%), vision impairment(6%; 95%CI 0.03–0.09; I² = 86.82%), intracerebral haemorrhage(5%; 95%CI 0.03–0.09; I² = 95.60%), seizure(4%; 95%CI 0.02 -0.05; I² = 98.15%), encephalitis(2%; 95%CI 0.01–0.03; I² = 90.36%), Guillan-Barré Syndrome (GBS) (1%; 95%CI 0.00–0.03; I² = 89.48%).

Conclusions

Neurological symptoms are common and varied in Covid-19 infections, and a growing number of reports suggest that the prevalence of neurological symptoms may be increasing. In the future, the role of COVID-19 neurological symptoms in the progression of COVID-19 should be further studied, and its pathogenesis and assessment methods should be explored, to detect and treat early neurological complications of COVID-19 and reduce mortality.

Electrodiagnostic findings in patients with non-COVID-19- and COVID-19-related acute respiratory distress syndrome

BACKGROUND

Critical illness polyneuropathy and myopathy (CIPNM) is a frequent neurological manifestation in patients with acute respiratory distress syndrome (ARDS) from coronavirus disease 2019 (COVID-19) infection. CIPNM diagnosis is usually limited to clinical evaluation. We compared patients with ARDS from COVID-19 and other aetiologies, in whom a neurophysiological evaluation for the detection of CIPNM was performed. The aim was to determine if there were any differences between these two groups in frequency of CINPM and outcome at discharge from the intensive care unit (ICU).

MATERIALS AND METHODS

This was a single-centre retrospective study performed on mechanically ventilated patients consecutively admitted (January 2016-June 2020) to the ICU of Careggi Hospital, Florence, Italy, with ARDS of different aetiologies. Neurophysiological evaluation was performed on patients with stable ventilation parameters, but marked widespread hyposthenia (Medical Research Council score <48). Creatine phosphokinase (CPK), lactic dehydrogenase (LDH) and mean morning glycaemic values were collected.

RESULTS

From a total of 148 patients, 23 with COVID-19 infection and 21 with ARDS due to other aetiologies, underwent electroneurography/electromyography (ENG/EMG) recording. Incidence of CIPNM was similar in the two groups, 65% (15 of 23) in COVID-19 patients and 71% (15 of 21) in patients affected by ARDS of other aetiologies. At ICU discharge, subjects with CIPNM more frequently required ventilatory support, regardless the aetiology of ARDS.

CONCLUSION

ENG/EMG represents a useful tool in the identification of the neuromuscular causes underlying ventilator wean failure and patient stratification. A high incidence of CIPNM, with a similar percentage, has been observed in ARDS patients of all aetiologies.

Double Deletion of Angiotensin II Type 2 and Mas Receptors Accelerates Aging-Related Muscle Weakness in Male Mice

Background The activation of AT2 (angiotensin II type 2 receptor ) and Mas receptor by angiotensin II and angiotensin-(1-7), respectively, is the primary process that counteracts activation of the canonical renin-angiotensin system (RAS). Although inhibition of canonical RAS could delay the progression of physiological aging, we recently reported that deletion of Mas had no impact on the aging process in mice. Here, we used male mice with a deletion of only AT2 or a double deletion of AT2 and Mas to clarify whether these receptors contribute to the aging process in a complementary manner, primarily by focusing on aging-related muscle weakness. Methods and Results Serial changes in grip strength of these mice up to 24 months of age showed that AT2/Mas knockout mice, but not AT2 knockout mice, had significantly weaker grip strength than wild-type mice from the age of 18 months. AT2/Mas knockout mice exhibited larger sizes, but smaller numbers and increased frequency of central nucleation (a marker of aged muscle) of single skeletal muscle fibers than AT2 knockout mice. Canonical RAS-associated genes, inflammation-associated genes, and senescence-associated genes were highly expressed in skeletal muscles of AT2/Mas knockout mice. Muscle angiotensin II content increased in AT2/Mas knockout mice. Conclusions Double deletion of AT2 and Mas in mice exaggerated aging-associated muscle weakness, accompanied by signatures of activated RAS, inflammation, and aging in skeletal muscles. Because aging-associated phenotypes were absent in single deletions of the receptors, AT2 and Mas could complement each other in preventing local activation of RAS during aging.

Oral administration of angiotensin-(1-7) decreases muscle damage and prevents the fibrosis in rats after eccentric exercise

NEW FINDINGS

What is the central question of this study? Eccentric contraction exercises cause damage to muscle fibres and induce inflammatory responses. The exacerbation of this process can induce deposition of fibrous connective tissue, leading to decreased muscle function. The aim of this study was to examine the role of angiotensin-(1-7) in this context. What is the main finding and its importance? Our results show that oral treatment with angiotensin-(1-7) decreases muscle damage induced by eccentric exercise, reducing inflammation and fibrosis in the gastrocnemius and soleus muscles. This study shows a potential effect of angiotensin-(1-7) for the prevention of muscle injuries induced by physical exercise.

ABSTRACT

Eccentric contraction exercises cause damage to the muscle fibres and induce an inflammatory reaction. The protective effect of angiotensin-(1-7) [Ang-(1-7)] in skeletal muscle has led us to examine the role of this peptide in modifying processes associated with inflammation and fibrogenesis induced by eccentric exercise. In this study, we sought to investigate the effects of oral administration of Ang-(1-7) formulated in hydroxypropyl β-cyclodextrin (HPβ-CD) in prevention and treatment of muscle damage after downhill running. Male Wistar rats were divided into three groups: control (untreated and not exercised; n = 10); treated/exercised HPβ-CD Ang-(1-7) (n = 40); and treated/exercised HPβ-CD (n = 40). Exercised groups were subjected to a single eccentric contraction exercise session on a treadmill inclined to -13° at a constant speed of 20 m/min, for 60 min. Oral administration of HPβ-CD Ang-(1-7) and HPβ-CD was performed 3 h before the exercise protocol and daily as a single dose, until the end of the experiment. Samples were collected 4, 12, 24, 48 and 72 h after the exercise session. The animals treated with the Ang-(1-7) showed lower levels of creatine kinase, lower levels of tumor necrosis factor-α in soleus muscle and increased levels of interleukin-10 cytokines. The inflammatory cells and deposition of fibrous connective tissue in soleus and gastrocnemius muscles were lower in the group treated with Ang-(1-7). The results of this study show that treatment with an oral formulation of Ang-(1-7) enhances the process of repair of muscle injury induced by eccentric exercise.

CoQ10 augments candesartan protective effect against tourniquet-induced hind limb ischemia-reperfusion: Involvement of non-classical RAS and ROS pathways

Tourniquet is a well-established model of hind limb ischemia–reperfusion (HLI/R) in rats. Nevertheless, measures should be taken to alleviate the expected injury from ischemia/ reperfusion (I/R). In the present study, 30 adult male Sprague-Dawley rats were randomly divided into 5 groups (n = 6): control, HLI/R, HLI/R given candesartan (1 mg/kg, P.O); HLI/R given Coenzyme Q10 (CoQ10) (10 mg/kg, P.O); HLI/R given candesartan (0.5 mg/kg) and CoQ10 (5 mg/kg). The drugs were administered for 7 days starting one hour after reperfusion. Candesartan and CoQ10 as well as their combination suppressed gastrocnemius content of angiotensin II while they raised angiotensin-converting enzyme 2 (ACE2) activity, angiotensin (1–7) expression, and Mas receptor mRNA level. Consequently, candesartan and/or CoQ10 reversed the oxidative stress and inflammatory changes that occurred following HLI/R as demonstrated by the rise of SOD activity and the decline of MDA, TNF-α, and IL-6 skeletal muscle content. Additionally, candesartan and/or CoQ10 diminished gastrocnemius active caspase-3 level and phospho-p38 MAPK protein expression. Our study proved that CoQ10 enhanced the beneficial effect of candesartan in a model of tourniquet-induced HLI/R by affecting classical and non-classical renin-angiotensin system (RAS) pathway. To our knowledge, this is the first study showing the impact of CoQ10 on skeletal muscle RAS in rats.

Angiotensin 1-7 protects against ventilator-induced diaphragm dysfunction

Mechanical ventilation (MV) is a life‐saving instrument used to provide ventilatory support for critically ill patients and patients undergoing surgery. Unfortunately, an unintended consequence of prolonged MV is the development of inspiratory weakness due to both diaphragmatic atrophy and contractile dysfunction; this syndrome is labeled ventilator‐induced diaphragm dysfunction (VIDD). VIDD is clinically important because diaphragmatic weakness is an important contributor to problems in weaning patients from MV. Investigations into the pathogenesis of VIDD reveal that oxidative stress is essential for the rapid development of VIDD as redox disturbances in diaphragm fibers promote accelerated proteolysis. Currently, no standard treatment exists to prevent VIDD and, therefore, developing a strategy to avert VIDD is vital. Guided by evidence indicating that activation of the classical axis of the renin‐angiotensin system (RAS) in diaphragm fibers promotes oxidative stress and VIDD, we hypothesized that activation of the nonclassical RAS signaling pathway via angiotensin 1‐7 (Ang1‐7) will protect against VIDD. Using an established animal model of prolonged MV, our results disclose that infusion of Ang1‐7 protects the diaphragm against MV‐induced contractile dysfunction and fiber atrophy in both fast and slow muscle fibers. Further, Ang1‐7 shielded diaphragm fibers against MV‐induced mitochondrial damage, oxidative stress, and protease activation. Collectively, these results reveal that treatment with Ang1‐7 protects against VIDD, in part, due to diminishing oxidative stress and protease activation. These important findings provide robust evidence that Ang1‐7 has the therapeutic potential to protect against VIDD by preventing MV‐induced contractile dysfunction and atrophy of both slow and fast muscle fibers.

Neurological manifestations and complications of coronavirus disease 2019 (COVID-19): a systematic review and meta-analysis

BACKGROUND

The spectrum of neurological involvement in COVID-19 is not thoroughly understood. To the best of our knowledge, no systematic review with meta-analysis and a sub-group comparison between severe and non-severe cases has been published. The aim of this study is to assess the frequency of neurological manifestations and complications, identify the neurodiagnostic findings, and compare these aspects between severe and non-severe COVID-19 cases.

METHODS

A systematic search of PubMed, Scopus, EBSCO, Web of Science, and Google Scholar databases was conducted for studies published between the 1st of January 2020 and 22nd of April 2020. In addition, we scanned the bibliography of included studies to identify other potentially eligible studies. The criteria for eligibility included studies published in English language (or translated to English), those involving patients with COVID-19 of all age groups, and reporting neurological findings. Data were extracted from eligible studies. Meta-analyses were conducted using comprehensive meta-analysis software. Random-effects model was used to calculate the pooled percentages and means with their 95% confidence intervals (CIs). Sensitivity analysis was performed to assess the effect of individual studies on the summary estimate. A subgroup analysis was conducted according to severity. The main outcomes of the study were to identify the frequency and nature of neurological manifestations and complications, and the neuro-diagnostic findings in COVID-19 patients.

RESULTS

44 articles were included with a pooled sample size of 13,480 patients. The mean age was 50.3 years and 53% were males. The most common neurological manifestations were: Myalgia (22.2, 95% CI, 17.2 to 28.1%), taste impairment (19.6, 95% CI, 3.8 to 60.1%), smell impairment (18.3, 95% CI, 15.4 to 76.2%), headache (12.1, 95% CI, 9.1 to 15.8%), dizziness (11.3, 95% CI, 8.5 to 15.0%), and encephalopathy (9.4, 95% CI, 2.8 to 26.6%). Nearly 2.5% (95% CI, 1 to 6.1%) of patients had acute cerebrovascular diseases (CVD). Myalgia, elevated CK and LDH, and acute CVD were significantly more common in severe cases. Moreover, 20 case reports were assessed qualitatively, and their data presented separately.

CONCLUSIONS

Neurological involvement is common in COVID-19 patients. Early recognition and vigilance of such involvement might impact their overall outcomes.

Myofiber androgen receptor increases muscle strength mediated by a skeletal muscle splicing variant of Mylk4

Androgens have a robust effect on skeletal muscles to increase muscle mass and strength. The molecular mechanism of androgen/androgen receptor (AR) action on muscle strength is still not well known, especially for the regulation of sarcomeric genes. In this study, we generated androgen-induced hypertrophic model mice, myofiber-specific androgen receptor knockout (cARKO) mice supplemented with dihydrotestosterone (DHT). DHT treatment increased grip strength in control mice but not in cARKO mice. Transcriptome analysis by RNA-seq, using skeletal muscles obtained from control and cARKO mice treated with or without DHT, identified a fast-type muscle-specific novel splicing variant of Myosin light-chain kinase 4 (Mylk4) as a target of AR in skeletal muscles. Mylk4 knockout mice exhibited decreased maximum isometric torque of plantar flexion and passive stiffness of myofibers due to reduced phosphorylation of Myomesin 1 protein. This study suggests that androgen-induced skeletal muscle strength is mediated with Mylk4 and Myomesin 1 axis.

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DHT increases muscle strength through myofiber AR

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Myofiber AR increases a fast-type muscle-specific novel splicing variant of Mylk4

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MYLK4 regulates muscle strength and muscle stiffness

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MYLK4 induces phosphorylation of MYOM1

Neurological outcome and quality of life 3 months after COVID-19: A prospective observational cohort study

BACKGROUND AND PURPOSE

To assess neurological manifestations and health-related quality of life (QoL) 3 months after COVID-19.

METHODS

In this prospective, multicenter, observational cohort study we systematically evaluated neurological signs and diseases by detailed neurological examination and a predefined test battery assessing smelling disorders (16-item Sniffin Sticks test), cognitive deficits (Montreal Cognitive Assessment), QoL (36-item Short Form), and mental health (Hospital Anxiety and Depression Scale, Posttraumatic Stress Disorder Checklist-5) 3 months after disease onset.

RESULTS

Of 135 consecutive COVID-19 patients, 31 (23%) required intensive care unit (ICU) care (severe), 72 (53%) were admitted to the regular ward (moderate), and 32 (24%) underwent outpatient care (mild) during acute disease. At the 3-month follow-up, 20 patients (15%) presented with one or more neurological syndromes that were not evident before COVID-19. These included polyneuro/myopathy (n = 17, 13%) with one patient presenting with Guillain-Barré syndrome, mild encephalopathy (n = 2, 2%), parkinsonism (n = 1, 1%), orthostatic hypotension (n = 1, 1%), and ischemic stroke (n = 1, 1%). Objective testing revealed hyposmia/anosmia in 57/127 (45%) patients at the 3-month follow-up. Self-reported hyposmia/anosmia was lower (17%) at 3 months, however, improved when compared to the acute disease phase (44%; p < 0.001). At follow-up, cognitive deficits were apparent in 23%, and QoL was impaired in 31%. Assessment of mental health revealed symptoms of depression, anxiety, and posttraumatic stress disorders in 11%, 25%, and 11%, respectively.

CONCLUSIONS

Despite recovery from the acute infection, neurological symptoms were prevalent at the 3-month follow-up. Above all, smelling disorders were persistent in a large proportion of patients.

Quadriceps muscle power and optimal shortening velocity are inversely related to angiotensin converting enzyme activity in older men

Background: Methods which potentially could prevent age-related loss of muscle mass and function are still being sought. There are various attempts to use pharmacological agents to prevent loss of muscle mass, but the effectiveness of many of them still needs to be confirmed. One of the promising therapeutics are Angiotensin Converting Enzyme Inhibitors (ACEIs) and lowering of serum ACE activity. The goal of this study was to assess if taking Angiotensin Converting Enzyme Inhibitors (ACEI) and other angiotensin system blocking medications (ASBMs) can modify muscle performance in older men as well as to assess the association of serum ACE activity with muscle strength, power, muscle contraction velocity and functional performance. Methods: Seventy-nine older men took part in the study. Muscle function was assessed with hand grip strength, maximum power relative to body mass (Pmax) and optimal shortening velocity (Ʋopt) of the knee extensor muscles. Anthropometric data, ACE activity and functional performance were also measured. Results: Negative correlations between ACE activity and Pmax (rho=-0.29, p=0.04) as well as Ʋopt  (rho=-0.31, p=0.03) in a group of patients not taking ACEI and between ACE activity and Ʋopt (rho=-0.22, p=0.05) in the whole group of men were found. Positive relationship between age and ACE activity was demonstrated (rho=0.26, p=0.02). Age was the only selected variable in the multiple regression analyses to determine both Pmax and Ʋopt. Conclusions: Serum ACE activity negatively associates to muscle power and muscle contraction velocity. The issues related to the impact of taking ACEI on the maintenance of muscle function and functional performance in older man require further studies.

Quadriceps muscle power and optimal shortening velocity are inversely related to angiotensin converting enzyme activity in older men

Background: Methods which potentially could prevent age-related loss of muscle mass and function are still being sought. There are various attempts to use pharmacological agents to prevent loss of muscle mass, but the effectiveness of many of them still needs to be confirmed. One of the promising therapeutics are Angiotensin Converting Enzyme Inhibitors (ACEIs) and lowering of serum ACE activity. The goal of this study was to assess if taking Angiotensin Converting Enzyme Inhibitors (ACEI) and other angiotensin system blocking medications (ASBMs) can modify muscle performance in older men as well as to assess the association of serum ACE activity with muscle strength, power, muscle contraction velocity and functional performance. Methods: Seventy-nine older men took part in the study. Muscle function was assessed with hand grip strength, maximum power relative to body mass (Pmax) and optimal shortening velocity (Ʋopt) of the knee extensor muscles. Anthropometric data, ACE activity and functional performance were also measured. Results: Negative correlations between ACE activity and Pmax (rho=-0.29, p=0.04) as well as Ʋopt  (rho=-0.31, p=0.03) in a group of patients not taking ACEI and between ACE activity and Ʋopt (rho=-0.22, p=0.05) in the whole group of men were found. Positive relationship between age and ACE activity was demonstrated (rho=0.26, p=0.02). Age was the only selected variable in the multiple regression analyses to determine both Pmax and Ʋopt. Conclusions: Taking ACEI is not associated with a functional performance in older men of the same age and with the same anthropometric parameters. Serum ACE activity negatively associates to muscle power and muscle contraction velocity.

Reassessing Sarcopenia in Hypertension: STAR and ACE Inhibitors Excel

BACKGROUND

Hypertension and sarcopenia are commonly seen in older adults. The renin-angiotensin system and the therapeutic use of angiotensin-converting enzyme (ACE) inhibitors have been on the agenda of sarcopenia in different perspectives. Our aim was to explore the frequency of sarcopenia in patients with hypertension and to investigate the association between the use of ACE inhibitors and sarcopenia.

METHODS

A total of 272 community-dwelling adults were recruited. Anterior thigh muscle thickness was measured by ultrasound. Handgrip strength, gait speed, and chair stand test were evaluated. Low muscle mass was diagnosed in the presence of low sonographic thigh adjustment ratio (STAR) values and sarcopenia was diagnosed if low STAR values were coupled with low functional tests.

RESULTS

136 subjects (50.0%) had no comorbid disease; 102 (37.5%) had one, 21 (7.7%) had two, nine (3.3%) had three and four (1.5%) had four comorbid diseases. Both low muscle mass (41.9% vs 13.2%) and sarcopenia (32.2% vs 7.8%) were more commonly seen in hypertensive when compared with normotensive older adults. Subgroup analysis of older adults with hypertension revealed that sarcopenia was less prevalent (P = .003) in patients using ACE inhibitors (8.7%) than those using angiotensin II receptor blockers (48.7%) and other antihypertensive drugs (46.4%). After binary logistic regression analyses; only the presence of hypertension seemed to independently predict the development of sarcopenia in older adults [OR = 6.5 (95% CI: 2.4-17.8, P < .001)].

CONCLUSIONS

Sarcopenia is highly prevalent in hypertensive older adults. Amongst many antihypertensive medications, ACE inhibitors seem to have favourable effects on both disorders.

Is Guillain-Barré Syndrome Associated With COVID-19 Infection? A Systemic Review of the Evidence

Background: There is emerging evidence that Guillain-Barré syndrome (GBS) may be associated with coronavirus disease 2019 (COVID-19) infection. The aim of this review was to investigate the strength of the evidence. Method: The review was registered in PROSPERO (CDR42020184822). Three electronic databases, MEDLINE, PubMed, and Web of Science, and three preprint servers, MedRvix, ChemRvix, and BioRvix, were searched from December 2019 to 24th September 2020. Studies were included if they were on COVID-19 and of any design. Articles that are reviews or opinion were excluded. The selection process was carried out using EndNote and Rayyan software. The main outcomes in the study were study design, sample size, sex, age, overall GBS symptoms, other COVID-19 symptoms, comorbidity, timing between infection and the onset of neurological symptoms, CT, MRI, and EMG results. Methodological quality of the studies was assessed using the McMaster Critical Review Form. The collected data was analyzed using qualitative synthesis. Findings: Fifty-one high-quality studies (mostly) consisting of 83 patients were included in the study. All of the patients (except in a very few) in the included studies had confirmed diagnosis of COVID-19. Similarly, the diagnosis of GBS was based on standard clinical, electrophysiological, and cerebrospinal fluid (CSF) criteria. Conclusion: GBS may be associated with COVID-19, and therefore, testing for COVID-19 is recommended in patients presenting with GBS during this pandemic.

Role of hormones in sarcopenia

Aging involves numerous changes in body composition that include a decrease in skeletal muscle mass. The gradual reduction in muscle mass is associated with a simultaneous decrease in muscle strength, which leads to reduced mobility, fragility and loss of independence. This process called sarcopenia is secondary to several factors such as sedentary lifestyle, inadequate nutrition, chronic inflammatory state and neurological alterations. However, the endocrine changes associated with aging seem to be of special importance in the development of sarcopenia. On one hand, advancing age is associated with a decreased secretion of the main hormones that stimulate skeletal muscle mass and function (growth hormone, insulin-like growth factor 1 (IGFI), testosterone and estradiol). On the other hand, the alteration of the IGF-I signaling along with decreased insulin sensitivity also have an important impact on myogenesis. Other hormones that decline with aging such as the adrenal-derived dehydroepiandrosterone, thyroid hormones and vitamin D seem to also be involved in sarcopenia. Adipokines released by adipose tissue show important changes during aging and can affect muscle physiology and metabolism. In addition, catabolic hormones such as cortisol and angiotensin II can accelerate aged-induced muscle atrophy, as they are involved in muscle wasting and their levels increase with age. The role played by all of these hormones and the possible use of some of them as therapeutic tools for treating sarcopenia will be discussed.

ACE2, angiotensin 1-7 and skeletal muscle: review in the era of COVID-19

Angiotensin converting enzyme-2 (ACE2) is a multifunctional transmembrane protein recently recognised as the entry receptor of the virus causing COVID-19. In the renin–angiotensin system (RAS), ACE2 cleaves angiotensin II (Ang II) into angiotensin 1-7 (Ang 1-7), which is considered to exert cellular responses to counteract the activation of the RAS primarily through a receptor, Mas, in multiple organs including skeletal muscle. Previous studies have provided abundant evidence suggesting that Ang 1-7 modulates multiple signalling pathways leading to protection from pathological muscle remodelling and muscle insulin resistance. In contrast, there is relatively little evidence to support the protective role of ACE2 in skeletal muscle. The potential contribution of endogenous ACE2 to the regulation of Ang 1-7-mediated protection of these muscle pathologies is discussed in this review. Recent studies have suggested that ACE2 protects against ageing-associated muscle wasting (sarcopenia) through its function to modulate molecules outside of the RAS. Thus, the potential association of sarcopenia with ACE2 and the associated molecules outside of RAS is also presented herein. Further, we introduce the transcriptional regulation of muscle ACE2 by drugs or exercise, and briefly discuss the potential role of ACE2 in the development of COVID-19.

Angiotensin-(1-7) Prevents Lipopolysaccharide-Induced Autophagy via the Mas Receptor in Skeletal Muscle

Skeletal muscle atrophy, which occurs in lipopolysaccharide (LPS)-induced sepsis, causes a severe muscle function reduction. The increased autophagy contributes to sepsis-induced skeletal muscle atrophy in a model of LPS injection, increasing LC3II/LC3I ratio, autophagy flux, and autophagosomes. Angiotensin-(1-7) (Ang-(1-7)) has anti-atrophic effects via the Mas receptor in skeletal muscle. However, the impact of Ang-(1-7) on LPS-induced autophagy is unknown. In this study, we determined the effect of Ang-(1-7) on sepsis-induced muscle autophagy. C57BL6 wild-type (WT) mice and mice lacking the Mas receptor (KO Mas) were injected with LPS together with the systemic administration of Ang-(1-7) to determine autophagy in skeletal muscle. We also evaluated autophagy and p38 and c-Jun N-terminal kinase (JNK)activation. Our results show that Ang-(1-7) prevents LPS-induced autophagy in the diaphragm, tibialis anterior, and gastrocnemius of WT mice, which is demonstrated by a decrease in the LC3II/LC3I ratio and mRNA levels of lc3b and ctsl. This effect was lost in KO Mas mice, suggesting the role of the Mas receptor. The results in C2C12 cells show that Ang-(1-7) reduces several LPS-dependent effects, such as autophagy (LC3II/LC3I ratio, autophagic flux, and autophagosomes), activation of p38 and JNK, B-cell lymphoma-2 (BCL2) phosphorylation, and disassembly of the Beclin1/BCL2 complex. In conclusion, Ang-(1-7)/Mas receptor reduces LPS-induced autophagy in skeletal muscle. In vitro assays indicate that Ang-(1-7) prevents LPS-induced autophagy and modifies the MAPK signaling and the disassembly of a complex involved at the beginning of autophagy.