Muscle atrophy in aging and chronic diseases: is it sarcopenia or cachexia?

A Comparative Analysis of the SARC-F Questionnaire and the Malnutrition-Inflammation Score for Sarcopenia Risk Assessment and Negative Outcome Probability in Chronic Hemodialysis Patients

Background/Objectives: Protein-energy wasting (PEW) and sarcopenia are common in chronic hemodialysis (HD) patients, leading to numerous complications and increased mortality. This study aimed to compare the reliability of the SARC-F (Strength, Assistance in walking, Rise from a chair, Climb stairs, and Falls) and the Malnutrition-Inflammation Score (MIS) in assessing sarcopenia and predicting negative outcomes in HD patients. Methods: This cross-sectional study enrolled 109 HD patients. Nutritional assessments were performed, and blood samples were taken for routine blood laboratory investigations. The MIS was used as a scoring system to represent the severity of PEW, while the SARC-F was applied as an indicator of sarcopenia risk and general functional capacity. A multivariable logistic regression was conducted to analyze the association of several predictors with a negative cross-sectional outcome (death). Results: Patients with SARC-F scores ≥ 4 and MISs ≥ 6 were older, had significantly lower albumin and prealbumin levels, and more severe anemia. They were also more likely to report weight loss and poor appetite. A higher MIS was closely associated with unfavourable nutritional status according to the International Society of Renal Nutrition and Metabolism (ISRNM) criteria for PEW. However, in 71.25% of patients with satisfactory functional capacity (SARC-F scores 0-3), some form of PEW was still observed. After performing logistic regression modelling, only the MIS remained strongly associated with the probability of a negative outcome. Conclusions: The SARC-F alone often did not correspond to an increased sarcopenia risk or clear clinical and biochemical indicators of PEW in HD patients. When assessing nutritional risk in this group, it is recommended to use more detailed tools, such as the MIS, to ensure the accurate identification of those at the highest risk for negative outcomes.

Potential of Lycii Radicis Cortex as an Ameliorative Agent for Skeletal Muscle Atrophy

Lycii Radicis Cortex (LRC) is a traditional medicine in East Asia with various beneficial effects, including antioxidant, anti-inflammatory, anti-tumor, anti-diabetic, and anti-depressant properties. However, its potential effects on skeletal muscle atrophy have not been studied. In this study, the protective effects of LRC extract (LRCE) on dexamethasone (DEX)-induced muscle atrophy were investigated in C2C12 myotubes and mice. We evaluated the effect of LRCE on improving muscle atrophy using a variety of methods, including immunofluorescence staining, quantitative polymerase chain reaction (qPCR), Western blot, measurements of oxidative stress, apoptosis, ATP levels, and muscle tissue analysis. The results showed that LRCE improved myotube diameter, fusion index, superoxide dismutase (SOD) activity, mitochondrial content, ATP levels, expression of myogenin and myosin heavy chain (MHC), and reduced reactive oxygen species (ROS) production in dexamethasone-induced C2C12 myotubes. LRCE also enhanced protein synthesis and reduced protein degradation in the myotubes. In mice treated with DEX, LRCE restored calf thickness, decreased mRNA levels of muscle-specific RING finger protein 1 (MuRF1) and atrogin-1, and increased insulin-like growth factor 1 (IGF-1) mRNA level. Moreover, LRCE also repaired gastrocnemius muscle atrophy caused by DEX. Although human studies are not available, various preclinical studies have identified potential protective effects of LRCE against muscle atrophy, suggesting that it could be utilized in the prevention and treatment of muscle atrophy.

Unveiling the Potential of Nelumbo nucifera-Derived Liensinine to Target The Myostatin Protein and to Counteract Muscle Atrophy

Muscle atrophy refers to a decline in muscle mass and function, which has become a global concern due to the aging population. Various clinical trials have investigated the inhibitors of myostatin (MSTN). They have shown promising improvements in muscle function and quality of life. However, there are no drugs specifically targeting MSTN that have been approved for clinical use. In this study, we virtually screened liensinine (LIE), a food (Nelumbo nucifera)-derived compound, with low toxicity, from over 1.1 million compounds. We subsequently identified it as a potential candidate that targets MSTN by a cellular thermal shift assay (CETSA) and drug affinity response target stability (DARTS) assay. Further validation through cellular and in vivo studies demonstrated its promising potential in combating muscle atrophy. The mechanism of action may involve hindering the interaction between MSTN and the activin receptor type IIB (ActRIIB) and downregulating the expression of downstream proteins, including the muscle RING-finger protein-1 (MuRF-1) and muscle atrophy F-box (MAFbx)/Atrogin-1, ultimately promoting muscle regeneration. These results provide a strong foundation for future studies to explore the therapeutic potential of LIE in clinical settings.

Prevalence of Risk of Sarcopenia in Polish Elderly Population—A Population Study

Sarcopenia in the elderly population is a public health challenge, and there are few data on its prevalence in Europe. In this study, we investigated the prevalence of sarcopenia in the elderly Polish population and its association with the level of obesity and co-existing diseases. We conducted a population-based cross-sectional study involving 823 men and 1177 women aged 65 years and older, randomly selected from the population living in the territory of the Republic of Poland between 2017 and 2020. We analyzed the results of body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). Risk of sarcopenia was assessed with the simple questionnaire to rapidly diagnose sarcopenia (SARC-F), and sarcopenic obesity risk was defined as the combination of anthropometry and SARC-F results. In addition, we collected disease data with an author questionnaire. The prevalence of risk of sarcopenia was 18.6% (22.3% in women and 13.2% in men), and its incidence significantly increased with age in both sexes. The risk of sarcopenic obesity was more common in women than in men, and it was higher in the older age group, except for sarcopenic obesity diagnosed by the WHR criteria. The group of elderly with concomitant diseases had a higher risk of developing sarcopenia, which emphasizes the need to monitor sarcopenia when concomitant diseases are diagnosed. In both groups, risk of sarcopenia was associated with motor and respiratory system diseases, type 2 diabetes, and neurological diseases. This study highlights that the risk of sarcopenia in the elderly population affects women to a greater extent than men. It is important to identify the elderly at risk of sarcopenia in routine clinical practice to develop long-term prevention strategies.

Impact of Sarcopenia and Myosteatosis in Non-Cirrhotic Stages of Liver Diseases: Similarities and Differences across Aetiologies and Possible Therapeutic Strategies

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

γ-Oryzanol Improves Exercise Endurance and Muscle Strength by Upregulating PPARδ and ERRγ Activity in Aged Mice

SCOPE

γ-Oryzanol, a well-known antioxidant, has been used by body builders and athletes to boost strength and increase muscle gain, without major side effects. However, the effect of γ-Oryzanol on sarcopenia and the underlying molecular mechanism is poorly understood.

RESULTS

Aged mice fed with the γ-Oryzanol diet do not show significant changes in muscle weight, but show increased running endurance as well as improved grip strength. The expression and activity of PPARδ and ERRγ are increased in skeletal muscle of γ-Oryzanol supplemented mice. γ-Oryzanol upregulates oxidative muscle fibers by MEF2 transcription factor, and PGC-1α and ERRα expressions. Fatty acid oxidation related genes and mitochondria biogenesis are upregulated by γ-Oryzanol. In addition, γ-Oryzanol inhibits TGF-β-Smad-NADPH oxidase 4 pathway and inflammatory cytokines such as TNF-α, IL-1β, IL-6, and p65 NF-κB subunit, which cause skeletal muscle weakness. Collectively, γ-Oryzanol attenuates muscle weakness pathway and increases oxidative capacity by increasing PPARδ and ERRγ activity, which contributes to enhance strength and improve oxidative capacity in muscles, consequently enhancing exercise capacity in aged mice. Particularly, γ-Oryzanol directly binds to PPARδ.

CONCLUSIONS

These are the first findings showing that γ-Oryzanol enhances skeletal muscle function in aged mice by regulating PPARδ and ERRγ activity without muscle gain.

Prognostic role of sarcopenia in metastatic colorectal cancer patients during first-line chemotherapy: A retrospective study

BACKGROUND

Sarcopenia is a condition characterized by decreased skeletal muscle mass due to physiological ageing or to a concomitant disease such as neoplasia. In cancer patients, a low lean body mass is suggested to be a negative prognostic factor for survival and for the development of dose-limiting chemotherapy toxicities irrespective of disease stage.

AIM

To evaluate the prognostic role of sarcopenia in patients with metastatic colorectal cancer (mCRC) undergoing first-line chemotherapy.

METHODS

Our retrospective analysis included 56 mCRC patients who received first-line chemotherapy from 2014 to 2017 at the Medical Oncology Unit of our hospital. Computerized scans were performed before starting chemotherapy and at the first disease reassessment. Sarcopenia was assessed using the skeletal mass index = muscle area in cm²/(height in m²) calculated at the L3 vertebra. Overall survival and objective response rate were evaluated. Toxicities were analyzed during the first four cycles of therapy and graded according to Common Terminology Criteria for Adverse Events version 4.0. A loss of skeletal muscle mass ≥ 5% was considered indicative of deterioration in muscle condition.

RESULTS

Median age was 67 years and 35.7% of patients were ≥ 70 years old. Fourteen patients (25%) were sarcopenic at baseline computed tomography (CT) scan (7/33 men; 7/23 women); 5/14 sarcopenic patients were ≥ 70 years old. Median follow-up was 26.8 mo (3.8-66.8 mo) and median overall survival was 27.2 mo (95%CI: 23.3-37.3). Sarcopenia was not correlated to overall survival (P = 0.362), to higher toxicities reported during the first 4 cycles of chemotherapy (P = 1.0) or to response to treatment (P = 0.221). At the first disease reassessment, a skeletal muscle loss (SML) ≥ 5% was found in 17 patients (30.3%) 3 of whom were already sarcopenic at baseline CT scan, while 7 patients became sarcopenic. SML was not correlated to overall survival (P = 0.961). No statistically significant correlation was found between baseline sarcopenia and age (P = 1.0), body mass index (P = 0.728), stage at diagnosis (P = 0.355) or neutrophil/lymphocyte ratio (P = 0.751).

CONCLUSION

Neither baseline sarcopenia nor SML affected survival. In addition, baseline sarcopenia was not related to worse treatment toxicity. However, these results must be interpreted with caution due to the limited sample size.

Left Ventricular Mass Index as Potential Surrogate of Muscularity in Patients With Systemic Sclerosis Without Cardiovascular Disease

BACKGROUND

Systemic sclerosis (SSc) may be associated with protein-energy malnutrition. It was demonstrated that left ventricular mass (LVM) reflected poor nutrition status in SSc patients, and no data are available on LVM as a surrogate measure of muscularity. We aimed to evaluate, in SSc patients, the relationship between muscle mass and LVM as a novel indicator of muscularity in this setting.

METHODS

SSc patients and healthy controls (HCs) were considered and underwent echocardiography to assess LVM and LVM index (LVMI). Body composition, including fat-free mass index (FFMI), phase angle (PhA), and body cell mass index (BCMI), was analyzed by multifrequency bioelectrical impedance analysis.

RESULTS

Sixty-four SSc patients (aged 51 ± 13 years) and 30 HCs (aged 46 ± 13 years) were enrolled. BCMI and PhA were lower in SSc patients compared with HCs (P < .001). LVM and LVMI were not different between SSc patients and HCs (P = .068, P = .14, respectively). In SSc patients, a significant correlation was shown between LVMI and FFMI (τ = 0.192, P = .026); in multiple regression analysis, FFMI was significantly associated with the Malnutrition Universal Screening Tool (P < .0001), LVMI (P = .01), and disease severity scale (P = .02).

CONCLUSION

Changes in body composition were present in SSc patients, particularly in terms of BMCI and PhA. A correlation between LVMI and FFMI as indexes of muscularity exists in this cohort, suggesting that cardiac mass might be used as a surrogate of nutrition status in this setting.

Association between sarcopenia and levels of growth hormone and insulin-like growth factor-1 in the elderly

Background

Age-related sarcopenia is a serious global health issue in elderly individuals and for the community as it induces disability and significant economic burden. The purpose of the study is to understand the factors associated with sarcopenia and the role of growth hormone (GH) and insulin-like growth factor (IGF-1) in the occurrence of sarcopenia.

Methods

Elderly patients (n = 3276) were included in this cross-sectional study. Survey and measurement of body composition (bioelectrical impedance), grip strength, and step speed were performed according to the Asian Working Group on Sarcopenia (AWGS) diagnostic criteria. Hematological and hormonal indicators were compared between patients with and without sarcopenia in order to identify the associated factors.

Results

There were significant differences in the demographic parameters between the sarcopenia and non-sarcopenia groups (all P < 0.05). There were significant differences between the two groups regarding the blood levels of GH, IGF-1, testosterone (T), and mechanical growth factor (MGF) (all P < 0.001). Correlation analyses showed that the appendicular skeletal muscle mass (ASMI) was positively associated with gender and BMI, and with GH, T, IGF-1, MGF, BUN, Cr, and Hb levels, but negatively associated with HDL-C (all P < 0.05). Logistic multivariable regression analysis showed that IGF-1, MGF, BMI, and gender were independently associated with appendicular skeletal muscle mass (ASMI) (all P < 0.05).

Conclusions

GH and IGF-1 are associated with sarcopenia in the elderly. IGF-1 and MGF are independently associated with the reduction of skeletal muscle mass, along with BMI and gender.

Sarcopenia assessed using bioimpedance analysis is associated independently with significant liver fibrosis in patients with chronic liver diseases

AIM

Sarcopenia is common in patients with advanced fibrosis or cirrhosis. We investigated the correlation between sarcopenia and other clinical variables, in particular, significant liver fibrosis in patients with chronic liver diseases (CLDs).

PATIENTS AND METHODS

Patients with CLDs who underwent transient elastography (TE) and bioelectrical impedance analysis between 2015 and 2017 were retrospectively recruited. The sarcopenia index (SI) was calculated as follows: SI = total appendicular skeletal muscle mass (kg)/ body mass index (BMI) (kg/m). Sarcopenia was defined as SI less than 0.789 for men and less than 0.521 for women. Significant liver fibrosis and fatty liver were defined using TE liver stiffness value more than 7 kPa and controlled attenuation parameter more than 250 dB/m, respectively.

RESULTS

Of 2168 patients recruited, 218 (10.1%) had sarcopenia. Age, BMI, diabetes, hypertension, fasting glucose, aspartate aminotransferase, and liver stiffness value were correlated positively with sarcopenia (all P < 0.05), whereas male sex, viral etiology, obesity (BMI > 25 kg/m), total bilirubin, and serum albumin were correlated negatively with sarcopenia (all P < 0.05). On multivariate analysis, TE-defined significant liver fibrosis was associated independently with sarcopenia (odds ratio = 1.597; 95% confidence interval: 1.174-2.172; P = 0.003), together with age, male sex, viral etiology, and TE-defined fatty liver (all P < 0.05). Among the subgroups with ultrasonography-defined nonalcoholic fatty liver disease (n = 957), sarcopenia was also associated independently with TE-defined significant liver fibrosis (odds ratio = 1.887; 95% confidence interval: 1.261-2.823; P < 0.001).

CONCLUSION

Sarcopenia is associated independently with significant liver fibrosis in patients with CLDs. Further studies are required to determine whether interventions to improve muscle mass can improve liver fibrosis.

From guidelines to clinical practice: a roadmap for oncologists for nutrition therapy for cancer patients

Tackling malnutrition in cancer patients remains one of the most challenging tasks in clinical practice. Even though robust evidence exists stressing the role of nutritional status in relation to treatment outcome, its appropriate consideration in clinical practice is often lacking.

In this review, we discuss the significance of nutritional status and of malnutrition for the cancer patient. Drawn from experience and from current recommendations of the European Society for Clinical Nutrition and Metabolism (ESPEN), we propose concrete and manageable steps to routinely incorporate nutritional aspects in today’s oncological clinical practice.

Sarcopenia: A Time for Action. An SCWD Position Paper

The term sarcopenia was introduced in 1988. The original definition was a "muscle loss" of the appendicular muscle mass in the older people as measured by dual energy x-ray absorptiometry (DXA). In 2010, the definition was altered to be low muscle mass together with low muscle function and this was agreed upon as reported in a number of consensus papers. The Society of Sarcopenia, Cachexia and Wasting Disorders supports the recommendations of more recent consensus conferences, i.e. that rapid screening, such as with the SARC-F questionnaire, should be utilized with a formal diagnosis being made by measuring grip strength or chair stand together with DXA estimation of appendicular muscle mass (indexed for height2). Assessments of the utility of ultrasound and creatine dilution techniques are ongoing. Use of ultrasound may not be easily reproducible. Primary sarcopenia is aging associated (mediated) loss of muscle mass. Secondary sarcopenia (or disease-related sarcopenia) has predominantly focused on loss of muscle mass without the emphasis on muscle function. Diseases that can cause muscle wasting (i.e. secondary sarcopenia) include malignant cancer, COPD, heart failure, and renal failure and others. Management of sarcopenia should consist of resistance exercise in combination with a protein intake of 1 to 1.5 g/kg/day. There is insufficient evidence that vitamin D and anabolic steroids are beneficial. These recommendations apply to both primary (age-related) sarcopenia and secondary (disease related) sarcopenia. Secondary sarcopenia also needs appropriate treatment of the underlying disease. It is important that primary care health professionals become aware of and make the diagnosis of age-related and disease-related sarcopenia. It is important to address the risk factors for sarcopenia, particularly low physical activity and sedentary behavior in the general population, using a life-long approach. There is a need for more clinical research into the appropriate measurement for muscle mass and the management of sarcopenia. Accordingly, this position statement provides recommendations on the management of sarcopenia and how to progress the knowledge and recognition of sarcopenia.

Cullin-3 dependent deregulation of ACTN1 represents a new pathogenic mechanism in nemaline myopathy

Nemaline myopathy is a congenital neuromuscular disorder characterized by muscle weakness, fiber atrophy and presence of nemaline bodies within myofibers. However, the understanding of underlying pathomechanisms is lacking. Recently, mutations in KBTBD13, KLHL40 and KLHL41, three substrate adaptors for the E3-ubiquitin ligase Cullin-3, have been associated with early-onset nemaline myopathies. We hypothesized that deregulation of Cullin-3 and its muscle protein substrates may be responsible for the disease development. Using Cullin-3 knockout mice, we identified accumulation of non-muscle alpha-Actinins (ACTN1 and ACTN4) in muscles of these mice, which we also observed in KBTBD13 patients. Our data reveal that proper regulation of Cullin-3 activity and ACTN1 levels is essential for normal muscle and neuromuscular junction development. While ACTN1 is naturally downregulated during myogenesis, its overexpression in C2C12 myoblasts triggered defects in fusion, myogenesis and acetylcholine receptor clustering; features that we characterized in Cullin-3 deficient mice. Taken together, our data highlight the importance for Cullin-3 mediated degradation of ACTN1 for muscle development, and indicate a new pathomechanism for the etiology of myopathies seen in Cullin-3 knockout mice and nemaline myopathy patients.

Quantitative analysis of skeletal muscle by computed tomography imaging-State of the art

The radiological assessment of muscle properties-size, mass, density (also termed radiodensity), composition, and adipose tissue infiltration-is fundamental in muscle diseases. More recently, it also became obvious that muscle atrophy, also termed muscle wasting, is caused by or associated with many other diseases or conditions, such as inactivity, malnutrition, chronic obstructive pulmonary disorder, cancer-associated cachexia, diabetes, renal and cardiac failure, and sarcopenia and even potentially with osteoporotic hip fracture. Several techniques have been developed to quantify muscle morphology and function. This review is dedicated to quantitative computed tomography (CT) of skeletal muscle and only includes a brief comparison with magnetic resonance imaging. Strengths and limitations of CT techniques are discussed in detail, including CT scanner calibration, acquisition and reconstruction protocols, and the various quantitative parameters that can be measured with CT, starting from simple volume measures to advanced parameters describing the adipose tissue distribution within muscle. Finally, the use of CT in sarcopenia and cachexia and the relevance of muscle parameters for the assessment of osteoporotic fracture illustrate the application of CT in two emerging areas of medical interest.

Collagen-induced arthritis as an animal model of rheumatoid cachexia

BACKGROUND

Rheumatoid arthritis is characterized by chronic polyarticular synovitis and presents systemic changes that impact quality of life, such as impaired muscle function, seen in up to 66% of the patients. This can progress to severely debilitating state known as rheumatoid cachexia-without loss of fat mass and body weight-for which there is little consensus in terms of diagnosis or treatment. This study aims to evaluate whether the collagen-induced arthritis (CIA) animal model also develops clinical and functional features characteristic of rheumatoid cachexia.

METHODS

Male DBA1/J mice were randomly divided into 2 groups: healthy animals (CO, n = 11) and CIA animals (n = 13). The clinical score and edema size, animal weight and food intake, free exploratory locomotion, grip strength, and endurance exercise performance were tested 0, 18, 35, 45, 55, and 65 days after disease induction. After euthanasia, several organs, visceral and brown fat, and muscles were dissected and weighed. Muscles were used to assess myofiber diameter. Ankle joint was used to assess arthritis severity by histological score. Statistical analysis were performed using one-way and two-way analyses of variance followed by Tukey's and Bonferroni's test or t-test of Pearson and statistical difference were assumed for a P value under 0.05.

RESULTS

The CIA had significantly higher arthritis scores and larger hind paw edema volumes than CO. The CIA had decreased endurance exercise performance total time (fatigue; 23, 22, 24, and 21% at 35, 45, 55, and 65 days, respectively), grip strength (27, 55, 63, 60, and 66% at 25, 35, 45, 55, and 65 days, respectively), free locomotion (43, 57, 59, and 66% at 35, 45, 55, and 65 days, respectively), and tibialis anterior and gastrocnemius muscle weight (25 and 24%, respectively) compared with CO. Sarcoplasmic ratios were also reduced in CIA (TA: 23 and GA: 22% less sarcoplasmic ratio), confirming the atrophy of skeletal muscle mass in these animals than in CO. Myofiber diameter was also reduced 45% in TA and 41% in GA in CIA when compared with the CO. Visceral and brown fat were lighter in CIA (54 and 39%, respectively) than CO group.

CONCLUSIONS

The CIA model is a valid experimental model for rheumatoid cachexia given that the clinical changes observed were similar to those described in patients with rheumatoid arthritis.

Mediterranean Diet attenuates risk of frailty and sarcopenia: New insights and future directions

Sarcopenia and physical frailty are associated with progressive disability and predictive of negative health outcomes. Dietary interventions are considered the cornerstone in the management of sarcopenic symptomology and physical frailty. However few studies have investigated preventative strategies. Moreover, most studies have focused on the efficacy of individual nutrients or supplements rather than dietary patterns. The Mediterranean Diet (MedDiet) is a dietary pattern that provides evidence for an association between diet quality, healthy ageing and disease prevention. The purpose of this paper was to examine, synthesise and develop a narrative review of the current literature, investigating the potential benefits associated with adherence to a MedDiet and attenuation of physical frailty and sarcopenic symptomology in older adults. We also explored the underlying mechanisms underpinning the potential benefits of the MedDiet on ameliorating physical frailty and sarcopenic symptomology. Synthesis of the reviewed literature is suggestive of a decreased risk of physical frailty and sarcopenic symptomology with greater adherence to a MedDiet. We identified the anti-inflammatory and high antioxidant components of the MedDiet as two potential biological mechanisms involved. Due to a lack of evidence from RCTs to support the proposed physiological mechanisms, we suggest investigating these observations in older adults with type 2 diabetes (T2DM) whom are vulnerable to physical frailty and disability. A number of biological mechanisms describing the pathway to disability in older adults with T2DM have been postulated with many of these mechanisms potentially mitigated with dietary interventions involving the MedDiet. Exploring these mechanisms with the use of well-designed, longer-term dietary intervention studies in older adults with an increased vulnerability to physical frailty and sarcopenia is warranted.  

Ghrelin therapy improves lung and cardiovascular function in experimental emphysema

Background

Emphysema is a progressive disease characterized by irreversible airspace enlargement followed by a decline in lung function. It also causes extrapulmonary effects, such as loss of body mass and cor pulmonale, which are associated with shorter survival and worse clinical outcomes. Ghrelin, a growth-hormone secretagogue, stimulates muscle anabolism, has anti-inflammatory effects, promotes vasodilation, and improves cardiac performance. Therefore, we hypothesized that ghrelin might reduce lung inflammation and remodelling as well as improve lung mechanics and cardiac function in experimental emphysema.

Methods

Forty female C57BL/6 mice were randomly assigned into two main groups: control (C) and emphysema (ELA). In the ELA group (n=20), animals received four intratracheal instillations of pancreatic porcine elastase (PPE) at 1-week intervals. C animals (n=20) received saline alone (50 μL) using the same protocol. Two weeks after the last instillation of saline or PPE, C and ELA animals received ghrelin or saline (n=10/group) intraperitoneally (i.p.) daily, during 3 weeks. Dual-energy X-ray absorptiometry (DEXA), echocardiography, lung mechanics, histology, and molecular biology were analysed.

Results

In elastase-induced emphysema, ghrelin treatment decreased alveolar hyperinflation and mean linear intercept, neutrophil infiltration, and collagen fibre content in the alveolar septa and pulmonary vessel wall; increased elastic fibre content; reduced M1-macrophage populations and increased M2 polarization; decreased levels of keratinocyte-derived chemokine (KC, a mouse analogue of interleukin-8), tumour necrosis factor-α, and transforming growth factor-β, but increased interleukin-10 in lung tissue; augmented static lung elastance; reduced arterial pulmonary hypertension and right ventricular hypertrophy on echocardiography; and increased lean mass.

Conclusion

In the elastase-induced emphysema model used herein, ghrelin not only reduced lung damage but also improved cardiac function and increased lean mass. These findings should prompt further studies to evaluate ghrelin as a potential therapy for emphysema.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0668-9) contains supplementary material, which is available to authorized users.

Apigenin enhances skeletal muscle hypertrophy and myoblast differentiation by regulating Prmt7

Apigenin, a natural flavone abundant in various plant-derived foods including parsley and celery, has been shown to prevent inflammation and inflammatory diseases. However, the effect of apigenin on skeletal muscle hypertrophy and myogenic differentiation has not previously been elucidated. Here, we investigated the effects of apigenin on quadricep muscle weight and running distance using C57BL/6 mice on an accelerating treadmill. Apigenin stimulated mRNA expression of MHC (myosin heavy chain) 1, MHC2A, and MHC2B in the quadricep muscles of these animals. GPR56 (G protein-coupled receptor 56) and its ligand collagen III were upregulated by apigenin supplementation, together with enhanced PGC-1α, PGC-1α1, PGC-1α4, IGF1, and IGF2 expression. Prmt7 protein expression increased in conjunction with Akt and mTORC1 activation. Apigenin treatment also upregulated FNDC5 (fibronectin type III domain containing 5) mRNA expression and serum irisin levels. Furthermore, apigenin stimulated C2C12 myogenic differentiation and upregulated total MHC, MHC2A, and MHC2B expression. These events were attributable to an increase in Prmt7-p38-myoD expression and Akt and S6K1 phosphorylation. We also observed that Prmt7 regulates both PGC-1α1 and PGC-1α4 expression, resulting in a subsequent increase in GPR56 expression and mTORC1 activation. Taken together, these findings suggest that apigenin supplementation can promote skeletal muscle hypertrophy and myogenic differentiation by regulating the Prmt7-PGC-1α-GPR56 pathway, as well as the Prmt7-p38-myoD pathway, which may contribute toward the prevention of skeletal muscle weakness.

Epidemiology of Sarcopenia: Determinants Throughout the Lifecourse

Sarcopenia is an age-related syndrome characterised by progressive and generalised loss of skeletal muscle mass and strength; it is a major contributor to the risk of physical frailty, functional impairment in older people, poor health-related quality of life and premature death. Many different definitions have been used to describe sarcopenia and have resulted in varying estimates of prevalence of the condition. The most recent attempts of definitions have tried to integrate information on muscle mass, strength and physical function and provide a definition that is useful in both research and clinical settings. This review focuses on the epidemiology of the three distinct physiological components of sarcopenia, and highlights the similarities and differences between their patterns of variation with age, gender, geography and time and the individual risk factors that cluster selectively with muscle mass, strength and physical function. Methods used to measure muscle mass, strength and physical functioning and how differences in these approaches can contribute to the varying prevalence rates will also be described. The evidence for this review was gathered by undertaking a systematic search of the literature. The descriptive characteristics of muscle mass, strength and function described in this review point to the urgent need for a consensual definition of sarcopenia incorporating these parameters.

Epidemiology of sarcopenia and insight into possible therapeutic targets

Musculoskeletal ageing is a major public health concern owing to demographic shifts in the population. Sarcopenia, generally defined as the age-related loss of muscle mass and function, is associated with considerable risk of falls, loss of independence in older adults and hospitalization with poorer health outcomes. This condition is therefore associated with increased morbidity and health care costs. As with bone mass, muscle mass and strength increase during late adolescence and early adulthood, but begin to decline substantially from ∼50 years of age. Sarcopenia is characterized by many features, which include loss of muscle mass, altered muscle composition, infiltration with fat and fibrous tissue and alterations in innervation. A better understanding of these factors might help us to develop strategies that target these effects. To date, however, methodological challenges and controversies regarding how best to define the condition, in addition to uncertainty about what outcome measures to consider, have delayed research into possible therapeutic options. Most pharmacological agents investigated to date are hormonal, although new developments have seen the emergence of agents that target myostatin signalling to increase muscle mass. In this review we consider the current approaching for defining sarcopenia and discuss its epidemiology, pathogenesis, and potential therapeutic opportunities.

Autophagy is induced in the skeletal muscle of cachectic cancer patients

Basal rates of autophagy can be markedly accelerated by environmental stresses. Recently, autophagy has been involved in cancer-induced muscle wasting. Aim of this study has been to evaluate if autophagy is induced in the skeletal muscle of cancer patients. The expression (mRNA and protein) of autophagic markers has been evaluated in intraoperative muscle biopsies. Beclin-1 protein levels were increased in cachectic cancer patients, suggesting autophagy induction. LC3B-I protein levels were not significantly modified. LC3B-II protein levels were significantly increased in cachectic cancer patients suggesting either increased autophagosome formation or reduced autophagosome turnover. Conversely, p62 protein levels were increased in cachectic and non-cachectic cancer patients, suggesting impaired autophagosome clearance. As for mitophagy, both Bnip3 and Nix/Bnip3L show a trend to increase in cachectic patients. In the same patients, Parkin levels significantly increased, while PINK1 was unchanged. At gene level, Beclin-1, p-62, BNIP3, NIX/BNIP3L and TFEB mRNAs were not significantly modulated, while LC3B and PINK1 mRNA levels were increased and decreased, respectively, in cachectic cancer patients. Autophagy is induced in the skeletal muscle of cachectic cancer patients, although autophagosome clearance appears to be impaired. Further studies should evaluate whether modulation of autophagy could represent a relevant therapeutic strategy in cancer cachexia.

The Prevalence and Prognostic Value of Low Muscle Mass in Cancer Patients: A Review of the Literature

: In several diseases, low muscle mass has been revealed as an unfavorable prognostic factor for outcome. Whether this holds true in patients with solid malignancies as well has increasingly been explored recently. However, this research field is severely hampered by a lack of consensus on how to determine muscle mass in cancer patients and on the definition of low muscle mass. Consequently, the prevalence of low muscle mass varies widely across several studies. Nevertheless, most studies show that, in patients with solid malignancies, low muscle mass is associated with a poor outcome. In the future, more research is needed to get better insight into the best method to determine muscle mass, the exact prognostic value of low muscle mass in diverse tumor types and stages, pathophysiology of low muscle mass in patients with cancer, and ways to intervene and improve muscle mass in patients. This review addresses the current literature on the importance of muscle mass in cancer patients and the methods of muscle measurement.

IMPLICATIONS FOR PRACTICE

An increasing number of studies underline the clinical value of low muscle mass as a prognostic factor for adverse outcomes in cancer patients. However, studies show large heterogeneity because of the lack of a standardized approach to measure muscle mass and the lack of reference populations. As a result, the interpretation of data and further progress are severely hampered, hindering the implementation of muscle measurement in oncological care. This review summarizes the methods of diagnosing low muscle mass in cancer patients, the difference between underlying syndromes such as sarcopenia and cachexia, and the association with clinical outcomes described so far.

Multiple gait parameters derived from iPod accelerometry predict age-related gait changes

INTRODUCTION

Normative data of how natural aging affects gait can serve as a frame of reference for changes in gait dynamics due to pathologies. Therefore, the present study aims (1) to identify gait variables sensitive to age-related changes in gait over the adult life span using the iPod and (2) to assess if these variables accurately distinguish young (aged 18-45) from healthy older (aged 46-75) adults.

METHODS

Trunk accelerations were recorded with an iPod Touch in 59 healthy adults during three minutes of overground walking. Gait variables included gait speed and accelerometry-based gait variables (stride, amplitude, frequency, and trajectory-related variables) in the anterior-posterior (AP) and medio-lateral (ML) directions. Multivariate partial least square analysis (PLS) identified variables sensitive to age-related differences in gait. To classify young and old adults, a PLS-discriminant analysis (PLS-DA) was used to test the accuracy of these variables.

RESULTS

The PLS model explained 42% of variation in age. Influential variables were: mean stride time, phase variability index, root mean square, stride variability, AP sample entropy and ML maximal Lyaponov exponent. PLS-DA classified 83% of the participants correctly with a sensitivity of 83% and specificity of 71%.

DISCUSSION

Contrary to the frequently reported high gait variability observed in old adults with frailty and fall history, the present study showed that younger compared with older healthy adults had a more variable, less predictable and more symmetrical gait pattern. A model based on a combination of variables reflecting gait dynamics, could distinguish healthy younger adults from older adults.

Current Clinical Care of Older Adults With Sarcopenia

As sarcopenia is common and associated with risk of adverse health consequences, strategies for clinical care of such patients are needed. Individuals with slow gait speed (<0.8 m/s) should be evaluated for low grip strength and low muscle mass. Progressive resistance exercise in patients with sarcopenia is beneficial, but evidence for protein or vitamin D supplementation is inconclusive. Comprehensive geriatric assessment with involvement of a multidisciplinary team enables clinicians to optimize treatment of complex older individuals with sarcopenia.

Efeito agudo do alongamento na marcha de idosas em terreno inclinado

Introdução O envelhecimento causa modificações musculares que influenciam negativamente a capacidade funcional dos idosos na locomoção, em especial durante a transposição de superfícies inclinadas. Essas mudanças geram redução da performance, diminuindo a mobilidade e aumentando o risco de queda na execução de tal tarefa. Os exercícios de alongamento podem reduzir a influência de dessas degenerações, preservando a capacidade muscular e a mobilidade. Objetivo O objetivo deste estudo foi avaliar a atuação do efeito agudo de uma sessão de exercícios de alongamento sobre a marcha de idosas durante a locomoção em uma rampa. Materiais e métodos Doze mulheres idosas, saudáveis e independentes, caminharam subindo e descendo uma rampa com inclinação de 10%. A análise cinemática (2D) e eletromiográfica foi realizada durante uma única sessão experimental, imediatamente antes (PRÉ) e após (PÓS) a realização de um exercício de alongamento estático dos flexores do quadril. Resultados O exercício de alongamento gerou aumento da amplitude (PRÉ 52,3 ± 18,30; PÓS 63,6 ± 16,90) e velocidade (PRÉ 195,8 ± 31,20/s; PÓS 241,8 ± 29,80/s) do quadril, assim como redução do tempo de ativação do tibial anterior (PRÉ TAFIN1 29,7 ± 6,7%; TAFIN2 100,0 ± 0,0%; PÓS TAFIN1 23,3 ± 7,4%; TAFIN2 87,7 ± 3,4%) e do bíceps femoral (PRÉ 45,0 ± 5,4%; PÓS 36,1 ± 10,4%) na subida na rampa. Na descida ocorreu aumento na velocidade da marcha (PRÉ 0,95 ± 0,18 m.s-1; PÓS 1,01 ± 0,22 m.s-1) e tamanho do passo (PRÉ 1,02 ± 0,15 m; PÓS 1,08 ± 0,18 m). Conclusão Os exercícios utilizados foram capazes de alterar de forma significativa os parâmetros avaliados, permitindo uma marcha mais veloz e reduzindo a ativação muscular. Estudos longitudinais são necessários para que os resultados aqui encontrados de forma temporária possam ser confirmados de forma permanente.

Novel TAZ modulators enhance myogenic differentiation and muscle regeneration

BACKGROUND AND PURPOSE

The transcriptional co-activator with PDZ-binding motif (TAZ) is a key controller of mesenchymal stem cell differentiation through its nuclear localization and subsequent interaction with master transcription factors. In particular, TAZ directly associates with myoblast determining protein D (MyoD) and activates MyoD-induced myogenic gene expression, thereby enhancing myogenic differentiation. Here, we have synthesized and characterized low MW compounds modulating myogenic differentiation via induction of TAZ nuclear localization.

EXPERIMENTAL APPROACH

COS7 cells stably transfected with GFP-TAZ were used in a high content imaging screen for compounds specifically enhancing nuclear localization of TAZ. We then studied the effects of such TAZ modulators on myocyte differentiation of C2C12 cells and myogenic transdifferentiation of mouse embryonic fibroblast cells in vitro and muscle regeneration in vivo.

KEY RESULTS

We identified two TAZ modulators, TM-53, and its structural isomer, TM-54. Each compound strongly enhanced nuclear localization of TAZ by reducing S89-phosphorylation and dose-dependently augmented myogenic differentiation and MyoD-mediated myogenic transdifferentiation through an activation of MyoD-TAZ interaction. The myogenic stimulatory effects of TM-53 and TM-54 were impaired in the absence of TAZ, but retrieved by the restoration of TAZ. In addition, administration of TM-53 and TM-54 enhanced injury-induced muscle regeneration in vivo and attenuated myofiber injury in vitro.

CONCLUSIONS AND IMPLICATIONS

The novel TAZ modulators TM-53 and TM-54 accelerated myogenic differentiation and improved muscle regeneration and function after injury, demonstrating that low MW compounds targeting the nuclear localization of TAZ have beneficial effects in skeletal muscle regeneration and in recovery from muscle degenerative diseases.

Dysregulation of skeletal muscle protein metabolism by alcohol

Alcohol abuse, either by acute intoxication or prolonged excessive consumption, leads to pathological changes in many organs and tissues including skeletal muscle. As muscle protein serves not only a contractile function but also as a metabolic reserve for amino acids, which are used to support the energy needs of other tissues, its content is tightly regulated and dynamic. This review focuses on the etiology by which alcohol perturbs skeletal muscle protein balance and thereby over time produces muscle wasting and weakness. The preponderance of data suggest that alcohol primarily impairs global protein synthesis, under basal conditions as well as in response to several anabolic stimuli including growth factors, nutrients, and muscle contraction. This inhibitory effect of alcohol is mediated, at least in part, by a reduction in mTOR kinase activity via a mechanism that remains poorly defined but likely involves altered protein-protein interactions within mTOR complex 1. Furthermore, alcohol can exacerbate the decrement in mTOR and/or muscle protein synthesis present in other catabolic states. In contrast, alcohol-induced changes in muscle protein degradation, either global or via specific modulation of the ubiquitin-proteasome or autophagy pathways, are relatively inconsistent and may be model dependent. Herein, changes produced by acute intoxication versus chronic ingestion are contrasted in relation to skeletal muscle metabolism, and limitations as well as opportunities for future research are discussed. As the proportion of more economically developed countries ages and chronic illness becomes more prevalent, a better understanding of the etiology of biomedical consequences of alcohol use disorders is warranted.

The role for dietary omega-3 fatty acids supplementation in older adults

Optimal nutrition is one of the most important determinants of healthier ageing, reducing the risk of disability, maintaining mental and physical functions, and thus preserving and ensuring a better quality of life. Dietary intake and nutrient absorption decline with age, thus increasing the risk of malnutrition, morbidity and mortality. Specific nutrients, particularly long-chain omega-3 polyunsaturated fatty acids (PUFAs), might have the potential of preventing and reducing co-morbidities in older adults. Omega-3 PUFAs are able to modulate inflammation, hyperlipidemia, platelet aggregation, and hypertension. Different mechanisms contribute to these effects, including conditioning cell membrane function and composition, eicosanoid production, and gene expression. The present review analyzes the influence of omega-3 PUFAs status and intake on brain function, cardiovascular system, immune function, muscle performance and bone health in older adults. Omega-3 FAs may have substantial benefits in reducing the risk of cognitive decline in older people. The available data encourage higher intakes of omega-3 PUFAs in the diet or via specific supplements. More studies are needed to confirm the role of omega-3 FAs in maintaining bone health and preventing the loss of muscle mass and function associated with ageing. In summary, omega-3 PUFAs are now identified as potential key nutrients, safe and effective in the treatment and prevention of several negative consequences of ageing.

Development and decline of upright gait stability

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers.

Development and relative validity of a new field instrument for detection of geriatric cachexia: preliminary analysis in hip fracture patients

BACKGROUND

Geriatric cachexia is distinct from other age-related muscle wasting syndromes; however, detection and therefore treatment is challenging without the availability of valid instruments suitable for application in the clinical setting. This study assessed the sensitivity and specificity of a newly developed screening instrument utilising portable assessments against previously defined and commonly accepted diagnostic criteria for detection of geriatric cachexia.

METHODS

Cross-sectional analyses from 71 older adults' post-surgical fixation for hip fracture were performed. The diagnostic criteria required measures of appendicular skeletal muscle index derived from dual-energy X-ray absorptiometry and anorexia assessed by ≤70 % of estimated energy requirements. These assessments were replaced with mid-upper arm muscle circumference and the Simplified Nutritional Appetite Questionnaire, respectively, to create a field instrument suitable for screening geriatric cachexia. Sensitivity, specificity and positive and negative predictive values were calculated.

RESULTS

The current diagnostic algorithm identified few patients as cachectic (4/71; 5.6 %). The sensitivity and specificity of the geriatric cachexia screening tool was 75 and 97 %, respectively. The screening tool had a positive predictive value of 60 % and a negative predictive value of 99 %.

CONCLUSIONS

Given the unexpected prevalence of cachexia in such a vulnerable group, these results may suggest problems in operationalising of the consensus definition and diagnostic criteria. Although the application of a newly developed screening tool using portable field measures looks promising, the authors recommend additional research to identify the prevalence of geriatric cachexia, which captures all diagnostic criteria from the consensus definition. Future investigation may then be positioned to explore the predictive validity of screening tools using portable field measures, which potentially achieve higher sensitivity.