Heart Failure-Induced Skeletal Muscle Wasting

SGLT2 inhibitor dapagliflozin mitigates skeletal muscle pathology by modulating key proteins involved in glucose and ion homeostasis in an animal model of heart failure

Heart failure (HF) is a syndrome characterized by dyspnoea, fatigue and exercise intolerance. Among non-cardiac comorbidities which often accompany HF, skeletal muscle abnormalities impact patients' daily activities and quality of life. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have shown promise in improving clinical outcomes and enhancing physical performance in HF patients, although their mechanism of action remains unclear. In this context, altered muscle ions and glucose homeostasis may contribute to HF-related muscle changes and serve as indirect targets for SGLT2i effects. To explore this further, we used Dahl salt-sensitive rats fed with a high-salt diet for five weeks and then randomized to receive dapagliflozin (HS + DAP) or vehicle (HS) for the following six weeks. Control animals received a low-salt diet (LS). We investigated whether variations in indexes of glucose and ions homeostasis occur in extensor digitorum longus muscle of this rodent model of HF with preserved ejection fraction and are counteracted by dapagliflozin treatment. Gene and protein expression analysis revealed altered expression of proteins involved in glucose (SGLT2, GLUT4, GPD1) and Ca2+ and Na + homeostasis (NCX3, Ryr1, NHE1/6, Na+/K+-ATPase, Nav1.4) in HS vs LS animals. Furthermore, HS rats showed an increased CaMKII expression in its active phosphorylated form and a change in plasma pH toward acidification. Dapagliflozin treatment counteracted the altered expression of most of the components under investigation, also promoting an amelioration of atrophy indexes and a recovery of plasma pH. Thus, skeletal muscle appears highly responsive to SGLT2i treatment, supporting the potential of these drugs in mitigating HF-related muscle pathology.

Moderate exercise relieves heart failure-induced skeletal muscle atrophy through the inhibition of MAPK/SOCS3 signaling

Heart failure (HF) is a structural or functional abnormality of the heart, often accompanied by skeletal muscle atrophy and other complications. Exercise plays an important role in preventing muscle atrophy. However, the underlying molecular mechanisms related to skeletal muscle atrophy in HF still remain poorly understood. In this study, we constructed an HF rat model by abdominal aortic coarctation (AAC) and a C2C12 muscle atrophy cell model induced by angiotensin II (Ang II). The relevant protein expressions were analyzed using western blotting. The damage of myocardial tissue, gastrocnemius tissue and cells were assessed through echocardiography, ELISA, HE staining, and immunofluorescence staining. Findings from this study indicated that moderate exercise has beneficial effects on pathological damage in the myocardial and gastrocnemius tissues of rats, resulting in a reduction of NT-proBNP levels in the blood. Furthermore, it was observed that the expression levels of MAFbx and MuRF1 were downregulated, while MHC and MyoD expressions were elevated, and the expression of endoplasmic reticulum stress (ERS)-related proteins GRP78, p-eIF2α, p-IRE1α, p-PERK, CHOP, ATF6 was inhibited, and finally alleviated HF-induced skeletal muscle atrophy. The mechanism involves moderate exercise working to alleviate ERS by inhibiting the MAPK/SOCS3 signaling pathway, thus alleviating skeletal muscle atrophy induced by HF. Our study elucidates the positive role of moderate exercise in HF-induced skeletal muscle atrophy, reveals its potential molecular mechanism, and provides a new scientific basis for the comprehensive treatment of skeletal muscle atrophy in HF.

Exploring the potential of handgrip strength as a prognostic marker in acute decompensated heart failure with reduced ejection fraction: a cross-sectional study

Frailty is associated with poor outcomes in heart failure (HF). Handgrip strength (HGS) is a simple indicator of Physical frailty. We aimed to assess the prognostic value of HGS in patients under 60 years old with acute decompensated HF with reduced ejection fraction (HFrEF). In this cross-sectional study, we enrolled 125 patients with acute decompensated HFrEF. HGS was measured using a manual dynamometer. The primary outcome was in-hospital mortality. Univariate logistic regression analysis was performed to identify risk factors associated with in-hospital mortality. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive value of HGS for in-hospital mortality. The in-hospital mortality rate was 16%. Survivors had numerically higher, though not statistically significant, median HGS compared to non-survivors (18.8 (IQR: 13.2-25.3) kg vs. 13 (IQR: 11.4-19.5) kg; p = 0.06). HGS showed negative correlation with length of stay (rho = - 0.202, p = 0.024) and NT-proBNP levels (rho = - 0.256, p = 0.004). The area under the ROC curve for overall HGS predicting in-hospital mortality was 0.630 (p = 0.043). Lower left ventricular ejection fraction and higher NT-proBNP levels were significantly associated with increased odds of in-hospital mortality in univariate analysis. Lower handgrip strength was associated with longer hospital stay and higher NT-proBNP levels, and demonstrated a modest ability to predict in-hospital mortality. However, further research is necessary to establish standardized measurement methods and optimal prognostic thresholds before handgrip strength can be widely implemented in the management of this patient population.

Photobiomodulation and Physical Exercise Modulate of Cell Survival Proteins in the Skeletal Muscle of Rats with Heart Failure and Diabetes Mellitus

Introduction: Heart failure (HF) and type 2 diabetes mellitus (DM2) are global health problems that often lead to muscle atrophy. These conditions are associated with increased autophagy and apoptosis in the muscle cells, resulting in decreased muscle mass. Physical exercise associated with photobiomodulation (PBM) seems promising to attenuate the skeletal muscle changes caused by HF and DM2, due to its direct effects on mitochondria, which may result in an increase in antioxidant capacity. Objective: To verify the influence of physical exercise and the association with PBM on autophagy, apoptosis, and cell survival signaling pathways in myocytes from rats with HF and DM2. Materials and Methods: Male rats were assigned to one of four groups: control (CT), HF+DM (disease model), exercise+HF+DM (EX+HF+DM), and EX+HF+DM+PBM (EX+HF+DM+PBM). To induce DM2, we administered streptozotocin (STZ) (0.25 mL/kg, intraperitoneally). HF was induced by coronary ligation. One week post-induction, an 8-week aerobic exercise and PBM protocol was initiated. Western blot analysis was used to measure the expression of apoptosis-related proteins and autophagy. Results: The EX+HF+DM+PBM group showed a substantial increase in Nrf2, p-AKT, and LC3-I levels compared to the HF+DM group. Conclusions: These findings suggest that physical exercise combined with PBM can upregulate proteins that promote myocyte survival in rats with HF and DM2.

Histological changes in skeletal muscle induced by heart failure in human patients and animal models: A scoping review

OBJECTIVE

This scoping review aimed to characterize the histological changes in skeletal muscle after heart failure (HF) and to identify gaps in knowledge.

METHODS

On April 03, 2024, systematic searches were performed for papers in which histological analyses were conducted on skeletal muscle sampled from patients with HF or animal models of HF. Screening and data extraction were conducted by two independent authors.

RESULTS AND CONCLUSION

A total of 118 papers were selected, including 33 human and 85 animal studies. Despite some disagreements among studies, some trends were observed. These trends included a slow-to-fast transition, a decrease in muscle fiber size, capillary to muscle fiber ratio, and mitochondrial activity and content, and an increase in apoptosis. These changes may contribute to the fatigability and decrease in muscle strength observed after HF. Although there were some disagreements between the results of human and animal studies, the results were generally similar. Animal models of HF will therefore be useful in elucidating the histological changes in skeletal muscle that occur in human patients with HF. Because the muscles subjected to histological analysis were mostly thigh muscles in humans and mostly lower leg muscles in animals, it remains uncertain whether changes similar to those seen in lower limb (hindlimb) muscles after HF also occur in upper limb (forelimb) muscles. The results of this review will consolidate the current knowledge on HF-induced histological changes in skeletal muscle and consequently aid in the rehabilitation of patients with HF and future studies.

The Effect of Breathing and Relaxation Exercises on Self-Care, Dyspnea, and Fatigue in Heart Failure: A Randomized Controlled Study

Dyspnea, fatigue, and self-care are common occurrences of heart failure. This study evaluated the effects of yoga breathing and progressive muscle relaxation exercises on dyspnea, fatigue, and self-care in heart failure. The study conducted between April 2023 and March 2024 randomized 66 heart failure patients into 3 groups (yoga breathing exercise, progressive muscle relaxation exercise, and control). The intervention groups engaged in specific exercises tailored to their assigned regimen for 10 minutes twice daily over a 2-week period, while the control group maintained their pharmacological treatment. At the end of the intervention (second week) yoga breathing exercise notably ameliorated fatigue, dyspnea, and self-care (P < .001), changes in saturation, heart rate, and respiratory rate favoring the intervention groups (P < .05). Yoga breathing exercises enhance self-care, alleviate fatigue, and dyspnea in heart failure. Additionally, yoga breathing and progressive muscle relaxation exercises provide benefits in regulating saturation, heart rate, and respiratory rate in heart failure.

Association between heart failure in asymptomatic stages and skeletal muscle function assessed by ultrasonography in community-dwelling older adults

BACKGROUND

Symptomatic heart failure (HF) negatively affects the quantity and quality of skeletal muscles. However, the association between asymptomatic HF and skeletal muscle function remains unclear. We aimed to use ultrasonography to elucidate the association between asymptomatic HF and skeletal muscle function in community-dwelling older adults.

METHODS

This cross-sectional study comprised community-dwelling older adults aged ≥ 60 years who could perform activities of daily living independently and had never had symptomatic HF (n = 52, 76.3 ± 6.1 years). The participants were classified into three groups namely, non-HF (n = 26), stage A (n = 19), and stage B (n = 7) according to the HF stage criteria of the American Heart Association /American College of Cardiology /Heart Failure Society of America guideline. Skeletal muscle quantity and quality were assessed using ultrasonography (thickness and echo intensity) of the rectus femoris (RF) and vastus intermedius (VI) muscles. The group effects on muscle thickness and echo intensity in each group were assessed using a multivariate analysis.

RESULTS

Both muscles consistently demonstrated significant group effects on the thickness and echo intensity. Thicknesses of the RF (p = 0.020) and VI (p = 0.035) were lower in the stage B group than that in the non-HF group. The echo intensities in the RF (p = 0.006) and VI (p = 0.009) were higher in the stage B group than that in the non-HF group.

CONCLUSION

Asymptomatic HF negatively associated with the characteristics of skeletal muscle function, as assessed by ultrasonography in community-dwelling older adults. The stage B HF contributes to reduced skeletal muscle function as well as symptomatic HF.

Associations between metabolic overweight/obesity phenotypes and mortality risk among patients with chronic heart failure

Background

Metabolic disorders and overweight or obesity are highly prevalent and intricately linked in patients with chronic heart failure (CHF). However, it remains unclear whether there is an interactive effect between these conditions and the prognosis of heart failure, and whether such an interaction is influenced by stratification based on age and sex.

Methods

A total of 4,955 patients with CHF were enrolled in this study. Metabolic status was assessed according to the presence or absence of metabolic syndrome (MetS). BMI categories included normal weight and overweight or obesity (BMI < 24, ≥ 24 kg/m2). Patients were divided into four phenotypes according to their metabolic status and BMI: metabolically healthy with normal weight (MHNW), metabolically unhealthy with normal weight (MUNW), metabolically healthy with overweight or obesity (MHO), and metabolically unhealthy with overweight or obesity (MUO). The incidence of primary outcomes, including all-cause and cardiovascular (CV) death, was recorded.

Results

During a mean follow-up of 3.14 years, a total of 1,388 (28.0%) all-cause deaths and 815 (16.4%) CV deaths were documented. Compared to patients with the MHNW phenotype, those with the MUNW (adjusted hazard ratio [aHR], 1.66; 95% confidence interval [CI], 1.38-2.00) or MUO (aHR, 1.42 [95% CI, 1.24-1.63]) phenotypes had a greater risk of all-cause death, and those with the MHO phenotype (aHR, 0.61 [95% CI, 0.51-0.72]) had a lower risk of all-cause death. Moreover, the above phenomenon existed mainly among males and elderly females (aged ≥ 60 years). In nonelderly females (aged < 60 years), the detrimental effects of MetS were lower (aHR, 1.05 [95% CI, 0.63-1.75] among MUNW group and aHR, 0.52 [95% CI, 0.34-0.80] among MUO group), whereas the protective effects of having overweight or obesity persisted irrespective of metabolic status (aHR, 0.43 [95% CI, 0.26-0.69] among MHO group and aHR, 0.52 [95% CI, 0.34-0.80] among MUO group). Similar results were obtained in the Cox proportional risk analysis of the metabolic overweight/obesity phenotypes and CV death.

Conclusions

In male and elderly female patients with CHF, the detrimental effects of MetS outweighed the protective benefits of having overweight or obesity. Conversely, in nonelderly females, the protective effects of having overweight or obesity were significantly greater than the adverse impacts of MetS.

Bone marrow mesenchymal stem cells-derived exosomal lncRNA GAS5 mitigates heart failure by inhibiting UL3/Hippo pathway-mediated ferroptosis

BACKGROUND

Exosomes (Exos) are involved in the therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) on heart failure (HF). We investigated the molecular mechanisms underlying the involvement of BMSC-Exos in ferroptosis on HF.

METHODS

A rat model of HF and cellular model of hypoxia were established. BMSC-Exos were injected into model rats or co-cultured with model cells. In model rats, the cardiac function (echocardiography), oxidative stress (commercial kits), pathological damage (HE staining), fibrosis (MASSON staining), iron deposition (Prussian blue staining), and cell apoptosis (TUNEL staining) were examined. Viability (cell counting kit-8; CCK-8), cell cycle (flow cytometry), oxidative stress, and Fe2+ levels were detected in the model cells. GAS5, UL3, YAP, and TAZ expression were detected using qRT-PCR, western blotting, and immunohistochemistry analyses.

RESULTS

BMSC-Exos restored cardiac function and inhibited oxidative stress, apoptosis, pathological damage, fibrosis, and iron deposition in myocardial tissues of HF rats. In hypoxic cells, BMSC-Exos increased cell viability, decreased the number of G1 phase cells, decreased Fe2+ levels, and inhibited oxidative stress. Ferrostatin-1 (a ferroptosis inhibitor) exhibited a synergistic effect with BMSC-Exos. Additionally, GAS5 was upregulated in BMSC-Exos, further upregulating its target UL3 and Hippo pathway effectors (YAP and TAZ). The relieving effects of BMSC-Exos on HF or hypoxia-induced injury were enhanced by GAS5 overexpression, but weakened by UL3 silencing or verteporfin (a YAP inhibitor).

CONCLUSIONS

GAS5-harbouring BMSC-Exos inhibited ferroptosis by regulating the UL3/Hippo pathway, contributing to HF remission in vivo and in vitro.

Increased Expression of Proinflammatory Genes in Peripheral Blood Cells Is Associated with Cardiac Cachexia in Patients with Heart Failure with Reduced Ejection Fraction

Background: Cardiac cachexia (CC) in chronic heart failure with reduced ejection fraction (HFrEF) is characterized by catabolism and inflammation predicting poor prognosis. Levels of responsible transcription factors like signal transducer and activator of transcription (STAT)1, STAT3, suppressor of cytokine signaling (SOCS)1 and SOCS3 in peripheral blood cells (PBC) are underinvestigated in CC. Expression of mediators was related to patients' functional status, body composition (BC) and metabolic gene expression in skeletal muscle (SM). Methods: Gene expression was quantified by qRT-PCR in three cohorts: non-cachectic patients (ncCHF, n = 19, LVEF 31 ± 7%, BMI 30.2 ± 5.0 kg/m2), cachectic patients (cCHF; n = 18, LVEF 27 ± 7%, BMI 24.3 ± 2.5 kg/m2) and controls (n = 17, LVEF 70 ± 7%, BMI 27.6 ± 4.6 kg/m2). BC was assessed by dual-energy X-ray absorptiometry. Blood inflammatory markers were measured. We quantified solute carrier family 2 member 4 (SLC2A4) and protein degradation by expressions of proteasome 20S subunit beta 2 and calpain-1 catalytic subunit in SM biopsies. Results: TNF and IL-10 expression was higher in cCHF than in ncCHF and controls (all p < 0.004). cCHF had a lower fat mass index (FMI) and lower fat-free mass index (FFMI) compared to ncCHF and controls (p < 0.05). STAT1 and STAT3 expression was higher in cCHF vs. ncCHF or controls (1.1 [1.6] vs. 0.8 [0.9] vs. 0.9 [1.1] RU and 4.6 [5.5] vs. 2.5 [4.8] vs. 3.0 [4.2] RU, all ANOVA-p < 0.05). The same applied for SOCS1 and SOCS3 expression (1.1 [1.5] vs. 0.4 [0.4] vs. 0.4 [0.5] and 0.9 [3.3] vs. 0.4 [1.1] vs. 0.8 [0.9] RU, all ANOVA-p < 0.04). In cCHF, higher TNF and STAT1 expression was associated with lower FMI (r = 0.5, p = 0.053 and p < 0.05) but not with lower FFMI (p > 0.4). In ncCHF, neither cytokine nor STAT/SOCS expression was associated with BC (all p > 0.3). SLC2A4 was upregulated in SM of cCHF vs. ncCHF (p < 0.03). Conclusions: Increased STAT1, STAT3, SOCS1 and SOCS3 expression suggests their involvement in CC. In cCHF, higher TNF and STAT-1 expression in PBC were associated with lower FMI. Increased SLC2A4 in cachectic SM biopsies indicates altered glucose metabolism.

End-Of-Life Care for Patients With End-Stage Heart Failure, Comparisons of International Guidelines

Heart failure (HF) is a chronic, debilitating condition associated with significant morbidity, mortality, and socioeconomic burden. Patients with end-stage HF (ESHF) who are not a candidate for advanced therapies will continue to progress despite standard medical therapy. Thus, the focus of care shifts from prolonging life to controlling symptoms and improving quality of life through palliative care (PC). Because the condition and prognosis of HF patients evolve and can rapidly deteriorate, it is imperative to begin the discussion on end-of-life (EOL) issues early during HF management. These include the completion of an advance directive, do-not-resuscitate orders, and policies on device therapy and discontinuation as part of advance care planning (ACP). ESHF patients who do not have indications for advanced therapies or those who wish not to have a left ventricular assist device (LVAD) or heart transplant (HT) often experience high symptom burden despite adequate medical management. The proper identification and assessment of symptoms such as pain, dyspnea, nausea, depression, and anxiety are essential to the management of ESHF and may be underdiagnosed and undertreated. Psychological support and spiritual care are also crucial to improving the quality of life during EOL. Caregivers of ESHF patients must also be provided supportive care to prevent compassion fatigue and improve resilience in patient care. In this narrative review, we compare the international guidelines and provide an overview of end-of-life and palliative care for patients with ESHF.

The Role of Exercise in Cancer-Related Sarcopenia and Sarcopenic Obesity

One of the most common adverse effects of cancer and its therapeutic strategies is sarcopenia, a condition which is characterised by excess muscle wasting and muscle strength loss due to the disrupted muscle homeostasis. Moreover, cancer-related sarcopenia may be combined with the increased deposition of fat mass, a syndrome called cancer-associated sarcopenic obesity. Both clinical conditions have significant clinical importance and can predict disease progression and survival. A growing body of evidence supports the claim that physical exercise is a safe and effective complementary therapy for oncology patients which can limit the cancer- and its treatment-related muscle catabolism and promote the maintenance of muscle mass. Moreover, even after the onset of sarcopenia, exercise interventions can counterbalance the muscle mass loss and improve the clinical appearance and quality of life of cancer patients. The aim of this narrative review was to describe the various pathophysiological mechanisms, such as protein synthesis, mitochondrial function, inflammatory response, and the hypothalamic-pituitary-adrenal axis, which are regulated by exercise and contribute to the management of sarcopenia and sarcopenic obesity. Moreover, myokines, factors produced by and released from exercising muscles, are being discussed as they appear to play an important role in mediating the beneficial effects of exercise against sarcopenia.

Handgrip strength and the prognosis of patients with heart failure: A meta-analysis

BACKGROUND

Reduced muscular strength is common in patients with heart failure (HF). The aim of the systematic review and meta-analysis was to evaluate the association between handgrip strength (HGS) and prognosis of patients with HF.

HYPOTHESIS

Reduced HGS may be a risk factor of poor prognosis of patients with HF.

METHODS

Relevant observational studies with longitudinal follow-up were obtained by a comprehensive search of PubMed, Embase, Cochrane Library, and Web of Science databases. A random-effects model was used to pool the results.

RESULTS

Fifteen studies involving 7350 patients with HF were included in the meta-analysis. Pooled results showed that HF patients with lower HGS were associated with a higher risk of mortality during follow-up (risk ratio [RR]: 2.00, 95% confidence interval [CI]: 1.55-2.58, p < .001; I2  = 0%). Subgroup analysis showed that the association was not significantly affected by characteristics such as study country, design, mean age of the patients, HF status (stable or advanced/acute), HF type (reduced or preserved ejection fraction), follow-up duration, and quality score (p for subgroup difference all > 0.05). Further analysis showed that per 1 kgf decrease of HGS was associated with an 8% increased risk of mortality during follow-up (RR: 1.08, 95% CI: 1.05-1.11, p < .001; I2  = 12%). Moreover, HF patients with lower HGS were also related to a higher risk of composite outcome of HF rehospitalization or mortality (RR: 1.67, 95% CI: 1.19-2.35, p = .003; I2  = 53%).

CONCLUSION

A low HGS may be associated with poor clinical outcomes of patients with HF.

Effect of optimized new Shengmai powder on exercise tolerance in rats with heart failure by regulating the ubiquitin-proteasome signaling pathway

Introduction

Decreased exercise tolerance is a common symptom in patients with heart failure, which is closely related to protein degradation and apoptosis regulated by the ubiquitin-proteasome signaling (UPS) pathway. In this study, the effect of Chinese medicine, optimized new Shengmai powder, on exercise tolerance in rats with heart failure was investigated via the UPS pathway.

Methods

The heart failure model was prepared by ligating the left anterior descending branch of the coronary artery in rats, in which the sham-operated group was only threaded and not ligated. Rats (left ventricular ejection fraction ≤ 45%) were randomly divided into the following groups: model group, YHXSMS group, Benazepril group, and proteasome inhibitor Oprozomib group, and they were administered the corresponding drugs by gavage for 4 weeks. The cardiac function of rats was evaluated by performing an echocardiography examination and a hemodynamic test and the exercise tolerance was done by conducting an exhaustive swimming test. The mechanism was revealed by TUNEL detection, immunohistochemistry, immunofluorescence analysis, Western blot, and quantitative real-time PCR.

Results

The study showed that there was a decrease in cardiac function and exercise tolerance of rats in the model group and also destruction of cardiac and skeletal muscle fibers, a proliferation of collagen tissue, and an increment of apoptosis. Our study suggested that optimized new Shengmai powder could exert antiapoptotic effects on myocardial and skeletal muscle cells and improve myocardial contractility and exercise tolerance by inhibiting the overactivation of the UPS pathway, downregulating MAFbx, and Murf-1 overexpression, inhibiting the activation of the JNK signaling pathway, upregulating bcl-2 expression, and decreasing bax and caspase-3 levels.

Conclusions

The study showed that the optimized new Shengmai powder could improve cardiac function and exercise tolerance in rats with heart failure through the UPS pathway.

The Importance of Diaphragmatic Function in Neuromuscular Expression in Patients With Chronic Heart Failure

Chronic heart failure (CHF) is a set of symptoms and physical manifestations caused by the inability of the heart to perform its normal contractile function and satisfy the blood needs of all organs. This dysfunction leads to a non-physiological adaptation of all body systems, including the skeletal muscles and the diaphragm. The myopathy found in patients brings symptoms such as fatigue and intolerance to exercise, with an entity not always attributable to cardiac function. Neuromuscular incoordination is one of the symptoms related to CHF, causing an increased risk of mortality and hospitalization. The article reviews diaphragmatic adaptation in the presence of CHF and seeks to emphasize the importance of the diaphragm in understanding skeletal muscle incoordination in patients.

Revisiting skeletal myopathy and exercise training in heart failure: Emerging role of myokines

Exercise intolerance remains a major unmet medical need in patients with heart failure (HF). Skeletal myopathy is currently considered as the major limiting factor for exercise capacity in HF patients. On the other hand, emerging evidence suggest that physical exercise can decrease morbidity and mortality in HF patients. Therefore, mechanistic insights into skeletal myopathy may uncover critical aspects for therapeutic interventions to improve exercise performance in HF. Emerging data reviewed in this article suggest that the assessment of circulating myokines (molecules synthesized and secreted by skeletal muscle in response to contraction that display autocrine, paracrine and endocrine actions) may provide new insights into the pathophysiology, phenotyping and prognostic stratification of HF-related skeletal myopathy. Further studies are required to determine whether myokines may also serve as biomarkers to personalize the modality and dose of physical training prescribed for patients with HF and exercise intolerance. In addition, the production and secretion of myokines in patients with HF may interact with systemic alterations (e.g., inflammation and metabolic disturbances), frequently present in patients with HF. Furthermore, myokines may exert beneficial or detrimental effects on cardiac structure and function, which may influence adverse cardiac remodelling and clinical outcomes in HF patients. Collectively, these data suggest that a deeper knowledge on myokines regulation and actions may lead to the identification of novel physical exercise-based therapeutic approaches for HF patients.

The influence of a single transcranial direct current stimulation session on physical fitness in healthy subjects: a systematic review

Physical fitness is of indisputable importance for both health, and sports. Currently, the brain is being increasingly recognized as a contributor to physical fitness. Hereby, transcranial direct current stimulation (tDCS), as an ergogenic aid, has gained scientific interest. The current PRISMA-adherent review aimed to examine the effect of tDCS on the three core components of physical fitness: muscle strength, -endurance and cardiopulmonary endurance. Randomized controlled- or cross-over trials evaluating the effect of a single tDCS session (vs. sham) in healthy individuals were included. Hereby, a wide array of tDCS-related factors (e.g., tDCS montage and dose) was taken into account. Thirty-five studies (540 participants) were included. Between-study heterogeneity in factors such as age, activity level, tDCS protocol, and outcome measures was large. The capacity of tDCS to improve physical fitness varied substantially across studies. Nevertheless, muscle endurance was most susceptible to improvements following anodal tDCS (AtDCS), with 69% of studies (n = 11) investigating this core component of physical fitness reporting positive effects. The primary motor cortex and dorsolateral prefrontal cortex were targeted the most, with positive results being reported on muscle and cardiopulmonary endurance. Finally, online tDCS seemed most beneficial, and no clear relationship between tDCS and dose-related parameters seemed present. These findings can contribute to optimizing tDCS interventions during the rehabilitation of patients with a variety of (chronic) diseases such as cardiovascular disease. Therefore, future studies should focus on further unraveling the potential of AtDCS on physical fitness and, more specifically, muscle endurance in both healthy subjects and patients suffering from (chronic) diseases. This study was registered in Prospero with the registration number CRD42021258529. "To enable PROSPERO to focus on COVID-19 registrations during the 2020 pandemic, this registration record was automatically published exactly as submitted. The PROSPERO team has not checked eligibility".

Predictive value of serum irisin for chronic heart failure in patients with type 2 diabetes mellitus

We hypothesize that serum irisin can have additional discriminative potency for heart failure (HF) in individuals with type 2 diabetes mellitus (T2DM). The study group comprised 226 consecutive T2DM patients (153 patients with any HF phenotypes and 30 patients without HF) aged 41 to 65 years. The plasma levels N-terminal brain natriuretic pro-peptide (NT-proBNP) and irisin were detected by ELISA at the baseline of the study. We found that the most appropriate cut-off value of irisin (HF versus non-HF) were 10.4 ng/mL (area under curve [AUC] = 0.96, sensitivity = 81.0%, specificity = 88.0%; P = 0.0001). Cutoff point of NT-proBNP that distinguished patients with HF and without it was 750 pmol/L (AUC = 0.78; sensitivity = 72.7%, specificity 76.5%, p = 0.0001). Using multivariate comparative analysis we established that concentrations of irisin < 10.4 ng/mL (odds ration [OR] = 1.30; P = 0.001) and NT-proBNP > 750 pmol/mL (OR = 1.17; P = 0.042), left atrial volume index (LAVI) > 34 mL/m2 (OR = 1.06; P = 0.042) independently predicted HF. Irisin being added to NT-proBNP improved predictive modality for HF, whereas combination of NT-proBNP and LAVI > 34 mL/m2 did not. In conclusion, we established that irisin had independent predicted potency for HF in patients with established T2DM.

Discriminative Value of Serum Irisin in Prediction of Heart Failure with Different Phenotypes among Patients with Type 2 Diabetes Mellitus

Recent studies have shown that circulating levels of irisin are prognostic factors in heart failure (HF), but no data are available on the predictive role of irisin in patients with type 2 diabetes mellitus (T2DM) and different phenotypes of HF. The aim of the study was to investigate whether serum levels of irisin predict HF in T2DM patients. We prospectively included 183 participants with T2DM aged 41 to 62 years (30 non-HF patients and 153 HF patients) and 25 healthy volunteers in the study and evaluated clinical data, hemodynamics and biomarkers (N-terminal pro-brain natriuretic peptide (NT-proBNP) and irisin). Serum levels of irisin < 8.30 ng/mL were found to be a better indicator of HF with reduced ejection fraction (HFrEF) than irisin ≥ 8.30 ng/mL, but the predictive cut-off point for NT-proBNP remained the same as for HF with mildly reduced ejection fraction (HFmrEF). Serum levels of irisin < 10.4 ng/mL significantly improved the predictive ability of NT-proBNP for HF with preserved ejection fraction (HFpEF). In conclusion, we found that decreased serum levels of irisin significantly predicted HFpEF, rather than HFmrEF and HFrEF, in T2DM patients. This finding may open a new approach to HF risk stratification in T2DM patients.

Proteomics Reveals Long-Term Alterations in Signaling and Metabolic Pathways Following Both Myocardial Infarction and Chemically Induced Denervation

Myocardial infraction (MI) is the principal risk factor for the onset of heart failure (HF). Investigations regarding the physiopathology of MI progression to HF have revealed the concerted engagement of other tissues, such as the autonomic nervous system and the medulla oblongata (MO), giving rise to systemic effects, important in the regulation of heart function. Cardiac sympathetic afferent denervation following application of resiniferatoxin (RTX) attenuates cardiac remodelling and restores cardiac function following MI. While the physiological responses are well documented in numerous species, the underlying molecular responses during the initiation and progression from MI to HF remains unclear. We obtained multi-tissue time course proteomics with a murine model of HF induced by MI in conjunction with RTX application. We isolated tissue sections from the left ventricle (LV), MO, cervical spinal cord and cervical vagal nerves at four time points over a 12-week study. Bioinformatic analyses consistently revealed a high statistical enrichment for metabolic pathways in all tissues and treatments, implicating a central role of mitochondria in the tissue-cellular response to both MI and RTX. In fact, the additional functional pathways found to be enriched in these tissues, involving the cytoskeleton, vesicles and signal transduction, could be downstream of responses initiated by mitochondria due to changes in neuronal pulse frequency after a shock such as MI or the modification of such frequency communication from the heart to the brain after RTX application. Development of future experiments, based on our proteomic results, should enable the dissection of more precise mechanisms whereby metabolic changes in neuronal and cardiac tissues can effectively ameliorate the negative physiological effects of MI via RTX application.

Characterizing Sex Differences in Physical Frailty Phenotypes in Heart Failure

BACKGROUND

Although women with heart failure (HF) are potentially more likely to be physically frail compared with men with HF, the underlying contributors to this sex difference are poorly understood. The purpose of this study was to characterize sex differences in physical frailty phenotypes in HF.

METHODS

We prospectively enrolled adults with class I-IV HF. Physical frailty was measured with the frailty phenotype criteria. Symptoms of dyspnea, sleep-related impairment, pain interference, depression, and anxiety were assessed. Body composition was measured using dual-energy x-ray absorptiometry. Simple comparative statistics and stepwise regression modeling were used.

RESULTS

The average age of the sample (n=115) was 63.6±15.7 years, 49% were women, and 73% had nonischemic cause. Forty-three percent of the sample was physically frail. Women had a 4.6 times greater odds of being physically frail compared with men, adjusting for covariates (odds ratio=4.63 [95% CI, 1.81-11.84], P=0.001). Both physically frail men and women were characterized by more type 2 diabetes, higher comorbidity burden, and worse dyspnea symptoms. Physically frail women had significantly worse symptoms compared with non-physically frail women but no difference in body composition characteristics. Physically frail men had significantly lower appendicular muscle mass, higher percent fat, lower hemoglobin, and more depressive symptoms compared with non-physically frail men.

CONCLUSIONS

Women are significantly more likely to be physically frail compared with men in HF. Physical frailty in both women and men is characterized by comorbidities and worse symptoms; physical frailty in men is characterized by worse physiological characteristics.

Exercise Dynamic of Patients with Chronic Heart Failure and Reduced Ejection Fraction

PURPOSE OF REVIEW

Exercise causes various dynamic changes in all body parts either in healthy subject or in heart failure (HF) patients. The present review of current knowledge about HF patients with reduced ejection fraction focuses on dynamic changes along a "metabo-hemodynamic" perspective.

RECENT FINDINGS

Studies on the dynamic changes occurring during exercise span many years. Thanks to the availability of advanced methods, it is nowadays possible to properly characterize respiratory, hemodynamic, and muscular function adjustments and their mismatch with the pulmonary and systemic circulations. Exercise is a dynamic event that involves several body functions. In HF patients, it is important to know at what level the limitation takes place in order to better manage these patients and to optimize therapeutic strategies.

Myokines and Heart Failure: Challenging Role in Adverse Cardiac Remodeling, Myopathy, and Clinical Outcomes

Heart failure (HF) is a global medical problem that characterizes poor prognosis and high economic burden for the health system and family of the HF patients. Although modern treatment approaches have significantly decreased a risk of the occurrence of HF among patients having predominant coronary artery disease, hypertension, and myocarditis, the mortality of known HF continues to be unacceptably high. One of the most important symptoms of HF that negatively influences tolerance to physical exercise, well-being, social adaptation, and quality of life is deep fatigue due to HF-related myopathy. Myopathy in HF is associated with weakness of the skeletal muscles, loss of myofibers, and the development of fibrosis due to microvascular inflammation, metabolic disorders, and mitochondrial dysfunction. The pivotal role in the regulation of myocardial and skeletal muscle rejuvenation, attenuation of muscle metabolic homeostasis, and protection against ischemia injury and apoptosis belongs to myokines. Myokines are defined as a wide spectrum of active molecules that are directly synthesized and released by both cardiac and skeletal muscle myocytes and regulate energy homeostasis in autocrine/paracrine manner. In addition, myokines have a large spectrum of pleiotropic capabilities that are involved in the pathogenesis of HF including cardiac remodeling, muscle atrophy, and cardiac cachexia. The aim of the narrative review is to summarize the knowledge with respect to the role of myokines in adverse cardiac remodeling, myopathy, and clinical outcomes among HF patients. Some myokines, such as myostatin, irisin, brain-derived neurotrophic factor, interleukin-15, fibroblast growth factor-21, and growth differential factor-11, being engaged in the regulation of the pathogenesis of HF-related myopathy, can be detected in peripheral blood, and the evaluation of their circulating levels can provide new insights to the course of HF and stratify patients at higher risk of poor outcomes prior to sarcopenic stage.