Skeletal Muscle Abnormalities in Heart Failure

Association between cardiovascular disease risk and sarcopenia in community-dwelling Japanese older adults

AIM

Sarcopenia's high prevalence in older adults with cardiovascular disease (CVD) suggests that the risk of comorbidity in sarcopenia might also be increased during the at-risk phase of CVD. However, the relationship between CVD risk and sarcopenia has not been elucidated. Therefore, the purpose of this cross-sectional study was to investigate the association between CVD risk and sarcopenia in community-dwelling Japanese older adults.

METHODS

The participants in this cross-sectional study included 14 923 community-dwelling Japanese older adults (mean age 73.2 ± 5.6 years). The present study estimated the CVD risk using the revised World Health Organization risk chart, and classified CVD risk into "low" (<10%) and "mid-high" (≥10%). Assessments of sarcopenia, muscle mass, muscle strength and gait speed were measured based on the clinical definitions.

RESULTS

Among the participants, 654 people (4.4%) had sarcopenia, and 4857 (32.6%) had CVD mid-high risk. A multiple logistic model showed that the CVD mid-high risk was associated with sarcopenia (odds ratio [OR] 1.55, 95% confidence interval [CI] 1.28-1.89). In addition, CVD mid-high risk was associated with low muscle mass (OR 1.74, 95% CI 1.50-2.01), low muscle strength (OR 1.25, 95% CI 1.14-1.37) and slow gait speed (OR 1.17, 95% CI 1.07-1.27) in the adjusted model.

CONCLUSIONS

Among community-dwelling older adults, high or moderate CVD risk was associated with an increased risk of sarcopenia. Our findings could help identify older adults with a future high risk for sarcopenia. Geriatr Gerontol Int 2024; 24: 1328-1334.

Role of Irisin in exercise training-regulated endoplasmic reticulum stress, autophagy and myogenesis in the skeletal muscle after myocardial infarction

Patients with heart failure (HF) are often accompanied by skeletal muscle abnormalities, which can lead to exercise intolerance and compromise daily activities. Irisin, an exercise training (ET) -induced myokine, regulates energy metabolism and skeletal muscle homeostasis. However, the precise role of Irisin in the benefits of ET on inhibiting skeletal muscle atrophy, particularly on endoplasmic reticulum (ER) stress, autophagy, and myogenesis following myocardial infarction (MI) remains unclear. In this study, we investigated the expression of Irisin protein in wild-type mice with MI, and assessed its role in the beneficial effects of ET using an Fndc5 knockout mice. Our findings revealed that MI reduced muscle fiber cross-sectional area (CSA), while downregulating the expression of Irisin, PGC-1α and SOD1. Concurrently, MI elevated the levels of ER stress and apoptosis, and inhibited autophagy in skeletal muscle. Conversely, ET mitigated ER stress and apoptosis in the skeletal muscle of infarcted mice. Notably, Fndc5 knockout worsened MI-induced ER stress and apoptosis, suppressed autophagy and myogenesis, and abrogated the beneficial effects of ET. In conclusion, our findings highlight the role of Irisin in the ET-mediated alleviation of skeletal muscle abnormalities. This study provides valuable insights into MI-induced muscle abnormalities and enhances our understanding of exercise rehabilitation mechanisms in clinical MI patients.

Sex Differences in Skeletal Muscle Pathology in Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND

Women with heart failure and reduced ejection fraction (HFrEF) have greater symptoms and a lower quality of life compared with men; however, the role of noncardiac mechanisms remains poorly resolved. We hypothesized that differences in skeletal muscle pathology between men and women with HFrEF may explain clinical heterogeneity.

METHODS

Muscle biopsies from both men (n=22) and women (n=16) with moderate HFrEF (New York Heart Association classes I-III) and age- and sex-matched controls (n=18 and n=16, respectively) underwent transcriptomics (RNA-sequencing), myofiber structural imaging (histology), and molecular signaling analysis (gene/protein expression), with serum inflammatory profiles analyzed (enzyme-linked immunosorbent assay). Two-way ANOVA was conducted (interaction sex and condition).

RESULTS

RNA-sequencing identified 5629 differentially expressed genes between men and women with HFrEF, with upregulated terms for catabolism and downregulated terms for mitochondria in men. mRNA expression confirmed an effect of sex (P<0.05) on proatrophic genes related to ubiquitin proteasome, autophagy, and myostatin systems (higher in all men versus all women), whereas proanabolic IGF1 expression was higher (P<0.05) in women with HFrEF only. Structurally, women compared with men with HFrEF showed a pro-oxidative phenotype, with smaller but higher numbers of type I fibers, alongside higher muscle capillarity (Pinteraction<0.05) and higher type I fiber areal density (Pinteraction<0.05). Differences in gene/protein expression of regulators of muscle phenotype were detected between sexes, including HIF1α, ESR1, VEGF (vascular endothelial growth factor), and PGC1α expression (P<0.05), and for upstream circulating factors, including VEGF, IL (interleukin)-6, and IL-8 (P<0.05).

CONCLUSIONS

Sex differences in muscle pathology in HFrEF exist, with men showing greater abnormalities compared with women related to the transcriptome, fiber phenotype, capillarity, and circulating factors. These preliminary data question whether muscle pathology is a primary mechanism contributing to greater symptoms in women with HFrEF and highlight the need for further investigation.

Hemoglobin is an independent predictor of improvement exercise tolerance in male patients with non-ischemic cardiomyopathy

Exercise intolerance is a symptom of chronic heart failure (CHF). The magnitude of exercise tolerance, as measured by peak oxygen uptake (peak VO2), is strongly associated with prognosis in patients with CHF. We aimed to evaluate the factors associated with improved exercise tolerance in patients with HF. In this prospective study, we recruited patients who were diagnosed with non-ischemic cardiomyopathy between September 2017 and September 2021. All patients underwent cardiopulmonary exercise testing at discharge and 6 months after enrollment. The patients were stratified according to whether peak VO2 was increased or not at 6 months. One hundred patients with a reduced left-ventricular ejection fraction (LVEF < 50%) were enrolled. Improvement of peak VO2 was observed in 74 patients. In male patients, hemoglobin level was higher in the increased peak VO2 group than in the non-increased group (15.0 ± 1.9 g/dL vs. 13.1 ± 2.1 g/dL; p < 0.01). Baseline hemoglobin level was positively correlated with the percentage change in peak VO2 (Spearman's r = 0.248, p = 0.040). Kaplan-Meier analysis demonstrated that adverse cardiac events were significantly less frequent in the increased peak VO2 group than in the non-increased group (log-rank test, p = 0.032). Multivariate logistic regression analysis identified hemoglobin level as an independent predictor of improved peak VO2 [odds ratio (OR) 1.60; 95% confidence interval (CI) 1.05-2.44; p = 0.027]. Baseline hemoglobin level is an independent predictor of improved peak VO2 in male patients with non-ischemic cardiomyopathy.

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

BACKGROUND

The renin-angiotensin system (RAS) activation is a proposed mechanism of muscle wasting (MW i.e., reduction in muscle mass). Although we reported that RAS inhibitors (RASIs) were associated with lower prevalence of MW in heart failure (HF) patients, the relationship between mineralocorticoid receptor (MR) signaling and MW has not been analyzed.

METHODS AND RESULTS

We analyzed data from 320 consecutive Japanese HF patients who underwent dual-energy X-ray absorptiometry scanning for assessment of appendicular skeletal muscle mass index (ASMI). In multiple linear regression analyses, plasma renin activity (PRA) was negatively correlated with ASMI in patients not receiving RASIs, indicating an untoward role of the RAS in MW. Results of analysis of covariance in which risk factors of MW served as covariates showed that use of MR antagonists (MRAs) was associated with lower ASMI and higher PRA in the non-RASIs group. The close relationship between use of MRAs and lower ASMI or higher PRA in the non-RASIs group was confirmed in analyses in which the differences in baseline characteristics between users and non-users of MRAs were minimized by using an inverse probability of treatment weighting.

CONCLUSIONS

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

Determination of Peak Oxygen Uptake in Patients with Acute Myocardial Infarction: The Role of Arterial Stiffness in Cardio-Vascular-Skeletal Muscle Coupling

The relationship between arterial stiffness and oxygen uptake (VO2) in patients with acute myocardial infarction (AMI) remains unclear. We aimed to investigate this relationship and factors contributing to VO2 in patients with AMI. The role of arterial stiffness in cardio-skeletal muscle coupling during exercise was then elucidated. Upon discharge, we measured exercise capacity using cardiopulmonary exercise testing (CPX), assessed arterial stiffness with the cardio-ankle vascular index (CAVI), and determined body composition to assess the skeletal muscle mass of 101 patients with AMI. Patients were categorized based on their CAVI scores into three groups: (i) normal (CAVI: ≤7.9), (ii) borderline (CAVI: 8.0-8.9), and (iii) abnormal (CAVI: ≥9.0). Subsequently, VO2 was compared among these groups. The relationship between the CAVI and VO2 Peak during CPX and factors contributing to VO2 Peak were investigated. The abnormal CAVI group had a significantly lower VO2 Peak than the normal and borderline groups. The CAVI was associated with VO2 Peak. Furthermore, the CAVI was found to be a factor contributing to VO2 Peak. These findings suggest that arterial stiffness in tissue blood distribution and blood supply causes systemic exercise limits in patients with AMI. This suggests that arterial stiffness plays a significant role in cardio-vascular-skeletal muscle coupling.

Effectiveness of a cardiac rehabilitation program on biomechanical, imaging, and physiological biomarkers in elderly patients with heart failure with preserved ejection fraction (HFpEF): FUNNEL + study protocol

BACKGROUND

Patients with heart failure with preserved ejection fraction (HFpEF) have a low functional status, which in turn is a risk factor for hospital admission and an important predictor of survival in HFpEF. HFpFE is a heterogeneous syndrome and recent studies have suggested an important role for careful, pathophysiological-based phenotyping to improve patient characterization. Cardiac rehabilitation has proven to be a useful tool in the framework of secondary prevention in patients with HFpEF. Facilitating decision-making and implementing cardiac rehabilitation programs is a challenge in public health systems for HFpEF management. The FUNNEL + study proposes to evaluate the efficacy of an exercise and education-based cardiac rehabilitation program on biomechanical, physiological, and imaging biomarkers in patients with HFpEF.

METHODS

A randomised crossover clinical trial is presented among people older than 70 years with a diagnosis of HFpEF. The experimental group will receive a cardiac rehabilitation intervention for 12 weeks. Participants in the control group will receive one educational session per week for 12 weeks on HFpEF complications, functional decline, and healthy lifestyle habits. VO2peak is the primary outcome. Biomechanical, imaging and physiological biomarkers will be assessed as secondary outcomes. Outcomes will be assessed at baseline, 12 weeks, and 24 weeks.

DISCUSSION

Identifying objective functional parameters indicative of HFpEF and the subsequent development of functional level stratification based on functional impairment ("biomechanical phenotypes") may help clinicians identify cardiac rehabilitation responders and non-responders and make future clinical decisions. In this way, future pharmacological and non-pharmacological interventions, such as exercise, could be improved and tailored to improve quality of life and prognosis and reducing patients' hospital readmissions, thereby reducing healthcare costs.

TRIAL REGISTRATION

NCT05393362 (Clinicaltrials.gov).

Analysis of respiratory muscle strength and its relationship with functional capacity between different field tests in patients with heart failure

OBJECTIVE

To analyze respiratory muscle strength of patients with heart failure (HF) and correlate with functional capacity.

METHODS

This cross-sectional study involved patients with compensated HF of both sexes, aged above 18 years. Respiratory muscle strength was assessed by measuring maximum inspiratory (MIP) and expiratory pressures (MEP) using a manovacuometer. Patients were randomized into two groups to assess functional capacity: six-minute walk test (6MWT) and incremental shuttle walk test (ISWT).

RESULTS

Forty-eight patients were evaluated (23 from 6MWT and 25 from ISWT group). Most were male (67.8%), with mean age of 62.3 years and left ventricular ejection fraction of 40.8%. Mean predicted values of MIP [81.2% (74.7-87.8%)] and MEP [95.6% (88.2-103.0%)] did not indicate respiratory muscle weakness. The higher the New York Heart Association (NYHA) functional class, the lower the MIP (p = .011) and MEP (p = .016) values. Physically active patients presented higher respiratory muscle strength than those sedentary (MIP: 104.5 vs. 71.9 cmH2O, p < .001; MEP: 120.0 vs. 91.1 cmH2O, p = .004). Functional capacity was impaired [6MWT: 416.0 m (372.8-459.3 m); ISWT: 304 m (263.4-344.9 m)], and distance covered in the ISWT was shorter than 6MWT group (p < .001). Distance covered in the ISWT group presented a moderate positive correlation with MIP (r = 0.45; p = .022) and MEP (r = 0.41; p = .041).

CONCLUSION

Most patients with HF presented respiratory muscle strength close to predicted values; however, sedentary patients and those with high NYHA functional class, showed reduced MIP and MEP. Functional capacity was reduced, and MIP and MEP correlated with distance covered in the ISWT.

Skeletal muscle and heart failure - What is the relationship between central versus peripheral affections?

BACKGROUND AND AIM

Heart failure is considered as a systemic disease as beside the heart, skeletal muscle is affected.

METHODS AND RESULTS

In this retrospective case-control study 64 men and 15 women with heart failure as well as an individually pairwise matched sample by sex, age and body mass index of healthy individuals from the COmPLETE cohort study performed an exhaustive cardiopulmonary exercise test, strength tests and anthropometric measurements. V̇O2peak was 28.6% lower in male and 24.6% lower in female patients with heart failure as compared to healthy controls. Strength parameters are significantly higher for counter movement jump in male subjects. In females, significant differences were detected for mid-thigh pull in healthy versus patients with heart failure. Skeletal muscle mass of patients was in male as well as female 3.7% lower than in controls. Furthermore, the function of skeletal muscle seems impaired as the ability to accelerate is significantly lower in affected male with a heart pathology.

CONCLUSION

It seems that severe affections (approx. 25 to 30%) on cardiocirculatory level are associated with moderate to low affections on functional and structural capacity on skeletal muscle level. Further, as in the male cohort with a heart pathology acceleration meaning 'fast' contracting is impaired, it is suggested, that the central limitations respectively the low perfusion of skeletal muscle over years yield to adaptions on muscle cell level ingoing with a decreased ability of fast contracting. It is therefore suggested, that the central circulatory limitations in patients with heart failure, respectively the low perfusion of skeletal muscle over years, promote maladaptation's in the periphery.

The cardio-renal-metabolic connection: a review of the evidence

Type 2 diabetes (T2D), cardiovascular disease (CVD) and chronic kidney disease (CKD), are recognized among the most disruptive public health issues of the current century. A large body of evidence from epidemiological and clinical research supports the existence of a strong interconnection between these conditions, such that the unifying term cardio-metabolic-renal (CMR) disease has been defined. This coexistence has remarkable epidemiological, pathophysiologic, and prognostic implications. The mechanisms of hyperglycemia-induced damage to the cardio-renal system are well validated, as are those that tie cardiac and renal disease together. Yet, it remains controversial how and to what extent CVD and CKD can promote metabolic dysregulation. The aim of this review is to recapitulate the epidemiology of the CMR connections; to discuss the well-established, as well as the putative and emerging mechanisms implicated in the interplay among these three entities; and to provide a pathophysiological background for an integrated therapeutic intervention aiming at interrupting this vicious crosstalks.

Effects of aerobic exercise on cardiac function and gene expression of NADPH oxidases in diaphragm muscle of rats with aortic stenosis-induced heart failure

We evaluated the influence of aerobic physical exercise (EX) on gene-encoding proteins associated with oxidative stress in diaphragm muscle of rats with aortic stenosis-induced heart failure (HF). Wistar male rats were divided into four groups: Control sedentary (C); Control exercise (C-Ex); Sedentary aortic stenosis (AS); Aortic stenosis exercise (AS-Ex). Exercised rats trained 5 times a week for 10 weeks on a treadmill. Statistical analysis was performed by ANOVA or Kruskal-Wallis test. In the final echocardiogram, animals with aortic stenosis subjected to exercise demonstrated improvement in systolic function compared to the sedentary aortic stenosis group. In diaphragm muscle, the activity of antioxidant enzymes, malondialdehyde malondialdehyde concentration, protein carbonylation, and protein expression of p65 and its inhibitor IκB did not differ between groups. Alterations in gene expression of sources that generate reactive species of oxygen were observed in AS-Ex group, which showed decreased mRNA abundance of NOX2 and NOX4 compared to the aortic stenosis group (p < 0.05). We concluded that aerobic exercise has a positive impact during heart failure, ameliorating systolic dysfunction and biomarkers of oxidative stress in diaphragm muscle of rats with aortic stenosis-induced heart failure.

Association of resting energy expenditure-based energy intake sufficiency with functional recovery, dysphagia, and 1-year mortality following heart failure: A prospective observational study

AIM

Evidence for the influence of resting energy expenditure (REE)-based energy intake on the outcomes of patients with heart failure (HF) is scarce. This study evaluates the relationship between REE-based energy intake sufficiency and clinical outcomes in hospitalized HF patients.

METHODS

This prospective observational study included newly admitted patients with acute HF. REE was measured using indirect calorimetry at baseline and total energy consumption (TEE) was calculated by multiplying REE with activity index. Energy intake (EI) was recorded, and the patients were classified into two groups, namely, the energy intake sufficiency (i.e., EI/TEE ≥1) and energy intake deficiency groups (i.e., EI/TEE <1). The primary outcome was the performance of activities of daily living, assessed using the Barthel Index, at discharge. Other outcomes included dysphagia at discharge and all-cause 1-year mortality following discharge. Dysphagia was defined as a Food Intake Level Scale (FILS) score of <7. Multivariable analyses and Kaplan-Meier estimates were used to determine the association of energy sufficiency both at baseline and at discharge with the outcomes of interest.

RESULTS

The analysis included 152 patients (mean age, 79.7 years; 51.3% women); of them, 40.1% and 42.8% had inadequate energy intake both at baseline and at discharge, respectively. In multivariable analyses, energy intake sufficiency at discharge was significantly associated with the BI (β = 0.136, p = 0.002) and FILS score (odds ratio = 0.027, p < 0.001) at discharge. Moreover, energy intake sufficiency at discharge was associated with 1-year mortality after discharge (p < 0.001).

CONCLUSION

Adequate energy intake during hospitalization was associated with improved physical and swallowing functions and 1-year survival in HF patients. Adequate nutritional management is essential for hospitalized HF patients, suggesting that adequate energy intake may lead to optimal outcomes.

Accumulation of polyunsaturated fatty acid-derived metabolites in the sarcopenic muscle of aging mice

AIM

Although it is known that advanced age alters skeletal muscle lipid metabolism, the role(s) of polyunsaturated fatty acid-derived metabolites (mostly eicosanoids and docosanoids) in sarcopenia are not clear. We therefore examined the changes in the metabolites of arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid in the sarcopenic muscle of aged mice.

METHODS

We used 6- and 24-month-old male C57BL/6J mice as healthy and sarcopenic muscle models, respectively. Skeletal muscles were removed from the lower limb and subjected to a liquid chromatography-tandem mass spectrometry analysis.

RESULTS

The liquid chromatography-tandem mass spectrometry analysis detected distinct changes of metabolites in the muscles of the aged mice. Of the 63 metabolites identified, nine were significantly higher in the sarcopenic muscle of aged mice compared with the healthy muscle of young mice. In particular, prostaglandin E2 , prostaglandin F2a , thromboxane B2 , 5-hydroxyeicosatetraenoic acid, and 15-oxo-eicosatetraenoic acid (arachidonic acid-derived metabolites), 12-hydroxy-eicosapentaenoic acid and 14,15-epoxy-eicosatetraenoic acid (eicosapentaenoic acid-derived metabolites) and 10-hydroxydocosa-hexaenoic acid and 14-hydroxyoctadeca-pentaenoic acid (docosahexaenoic acid-derived metabolites) were significantly higher in aged tissue compared with young tissue (all P < 0.05).

CONCLUSIONS

We observed the accumulation of metabolites in the sarcopenic muscle of aged mice. Our results may provide new insights into the pathogenesis and progression of aging- or disease-related sarcopenia. Geriatr Gerontol Int 2023; 23: 297-303.

Impact of Sodium-Glucose Cotransporter-2 Inhibitors on Cardiac Bioenergetic Properties and Cardiorespiratory Fitness: A Special Effect of SGLT2i In Heart Failure?

Recent clinical trials have highlighted the profound benefits of sodium-glucose linked transporter 2 inhibitors (SGLT2i) on cardiovascular mortality and hospitalization for heart failure patients. Modest improvements in glycemic, lipid, or blood pressure control are unlikely to contribute to these significant beneficial outcomes, generating much interest in the relevant mechanisms leading to outcome improvements. In this review, we discuss the current evidence supporting a shift in myocardial substrate utilization from carbohydrates and fat oxidation toward energy efficient ketone bodies in the failing heart and the role of SGLT2i in this key metabolic adaptation to optimize myocardial fuel energetics. Further insights into the effect of SGLT2i on the indices of cardiorespiratory fitness are outlined and provide important clues into their mechanism of benefit. This mechanistic discussion in the context of recent trials of SGLT2i denotes a promising treatment paradigm of heart failure in individuals with and without diabetes.

Exploring the factors associated with decreased dynamic balance ability in older patients with heart failure

BACKGROUND

Older patients with heart failure (HF) have a higher prevalence of frailty and poorer dynamic balance ability than other community-dwelling older adults. However, the association of frailty and other clinical characteristics with dynamic balance ability in these patients remains unclear.

OBJECTIVES

We aimed to determine the clinical characteristics associated with decreased dynamic balance ability in older patients with HF.

METHODS

This observational study included patients aged ≥65 years who could walk independently and were admitted to our university hospitals to undergo a cardiac rehabilitation. The timed up and go test (TUG) was used to evaluate dynamic balance ability. Pearson's and Spearman's correlation analyses were performed to determine the relationships between TUG scores and clinical characteristics. A multiple regression model based on the forced entry method was used to determine independent predictors of TUG scores.

RESULTS

Of the 183 participants in this study (94 women; mean age, 82.5 ± 8.1 years), 116 (61.7%) had frailty. Pearson's and Spearman's correlation analyses revealed that age, frailty, sex, knee extensor muscle strength, maximum calf circumference, and Mini-Mental State Examination-Japanese version (MMSE-J) score were significantly correlated with TUG score (p < 0.001). Further, multiple regression analysis showed that age (p < 0.001), frailty (p = 0.041), knee extensor muscle strength (p = 0.002), and MMSE-J score (p = 0.048) were independent predictors of TUG scores.

CONCLUSION

Multiple factors, including age, frailty, knee extensor muscle weakness, and cognitive function impairment are independently associated with decreased dynamic balance ability in older patients with HF.

Association Between the Redox State of Human Serum Albumin and Exercise Capacity in Patients With Cardiac Disease

The redox state of human serum albumin (HSA) is reported to be an oxidative stress biomarker; however, its clinical use in cardiac disease has not yet been examined. This study aimed to investigate the relation between the redox state of HSA and exercise capacity, which is a robust prognostic factor, in patients with cardiovascular disease. This cross-sectional study included outpatients with cardiac disease. Exercise capacity was assessed by peak oxygen consumption (peakVO₂) measured using symptom-limited cardiopulmonary exercise testing. The high-performance liquid chromatography postcolumn bromocresol green method was used to part HSA into human nonmercaptalbumin (oxidized form) and human mercaptalbumin (HMA, reduced form). The fraction of human mercaptalbumin found in HSA (f[HMA]) was calculated as an indicator of the redox state of HSA. The association between peakVO₂ and f(HMA) was examined using the Spearman correlation coefficient and multivariate linear regression analysis. A total of 70 patients were included (median age 76 years; 44 men; median peakVO₂ 15.5 ml/kg/min). The f(HMA) was positively correlated with peakVO₂ (r = 0.38, p <0.01). Even after controlling for potential confounders, this association remained in the multivariate linear regression analysis (standardized beta = 0.24, p <0.05). We found a positive association between f(HMA) and peakVO₂, independent of potential confounders in patients with cardiac disease, suggesting that f(HMA) may be a novel biomarker related to exercise capacity in cardiac disease. Longitudinal studies are required to further examine the prognostic capability of f(HMA), the responsiveness to clinical intervention, and the association between f(HMA) and cardiac disease.

Efficacy of Ranolazine to Improve Diastolic Performance in Heart Failure with Preserved Ejection Fraction: A Systematic Review and Meta-analysis

This article evaluates the efficacy of using ranolazine to improve diastolic performance and exercise capacity in heart failure with preserved ejection fraction. A comprehensive literature review found eight trials where there are no significant difference in peak O2 (p=0.09) and exercise duration (p=0.18) between ranolazine and placebo. The ranolazine group had significantly higher and better diastolic parameters compared to placebo, with a mean difference of 0.45 (95% CI [27.18-39.50]). There were no significant differences for haemodynamic parameters (blood pressure and heart rate) and electrocardiography (QT interval) between ranolazine and placebo. The review found that ranolazine has good wefficacy to improve diastolic performance among heart failure with preserved ejection fraction patients and it does not affect blood pressure, heart rate and rate of ventricular repolarisation (shortening of the QT interval).

Skeletal muscle dysfunctions in pulmonary arterial hypertension: Effects of aerobic exercise training

Pulmonary arterial hypertension is associated with skeletal muscle myopathy and atrophy and impaired exercise tolerance. Aerobic exercise training has been recommended as a non-pharmacological therapy for deleterious effects imposed by pulmonary arterial hypertension. Aerobic physical training induces skeletal muscle adaptations via reduced inflammation, improved anabolic processes, decreased hypoxia and regulation of mitochondrial function. These benefits improve physical exertion tolerance and quality of life in patients with pulmonary arterial hypertension. However, the mechanisms underlying the therapeutic potential of aerobic exercise to skeletal muscle disfunctions in patients with pulmonary arterial hypertension are not well understood yet. This minireview highlights the pathways involved in skeletal muscle adaptations to aerobic exercise training in patients with pulmonary arterial hypertension.

Reduced upper and lower limb muscle strengths without reduced skeletal muscle in elderly patients with heart failure

Objective: This study aimed to characterize the muscle strength and skeletal muscle mass of patients with heart failure by investigating hand-grip strength, five times sit-to-stand (5STS) results, and skeletal muscle mass index (SMI). Materials and Methods: Muscle strength was assessed based on hand-grip strength and 5STS, while skeletal muscle mass was assessed using a bioelectrical impedance analyzer. Hierarchical logistic regression analysis was performed to explore the association between patients with heart failure and healthy elderly individuals. Results: Hierarchical logistic regression analysis was performed to examine the muscle strength and skeletal muscle mass characteristics in patients with heart failure. Hand-grip strength and 5STS responses but not SMI outcomes differed significantly between the two groups. The results of the hierarchical logistic regression analysis revealed that the hand-grip strength and 5STS were significant predictors of heart failure. The odds ratios for hand-grip strength and 5STS were 1.44 and 0.53, respectively. Conclusion: Our results suggested that upper and lower limb muscle strengths (handgrip strength and 5STS) in elderly patients with heart failure worsened significantly without a decrease in skeletal muscle mass.

Skeletal muscle abnormalities in heart failure with preserved ejection fraction

Almost half of all heart failure (HF) disease burden is due to HF with preserved ejection fraction (HFpEF). The primary symptom in patients with HFpEF, even when well compensated, is severe exercise intolerance and is associated with their reduced quality of life. Recently, studies showed that HFpEF patients have multiple skeletal muscle (SM) abnormalities, and these are associated with decreased exercise intolerance. The SM abnormalities are likely intrinsic to the HFpEF syndrome, not a secondary consequence of an epiphenomenon. These abnormalities are decreased muscle mass, reduced type I (oxidative) muscle fibers, and reduced type I-to-type II fiber ratio as well as a reduced capillary-to-fiber ratio, abnormal fat infiltration into the thigh SM, increased levels of atrophy genes and proteins, reduction in mitochondrial content, and rapid depletion of high-energy phosphate during exercise with markedly delayed repletion of high-energy phosphate during recovery in mitochondria. In addition, patients with HFpEF have impaired nitric oxide bioavailability, particularly in the microvasculature. These SM abnormalities may be responsible for impaired diffusive oxygen transport and/or impaired SM oxygen extraction. To date, exercise training (ET) and caloric restriction are some of the interventions shown to improve outcomes in HFpEF patients. Improvements in exercise tolerance following aerobic ET are largely mediated through peripheral SM adaptations with minimal change in central hemodynamics and highlight the importance of targeting SM to improve exercise intolerance in HFpEF. Focusing on the abnormalities mentioned above may improve the clinical condition of patients with HFpEF.

Feasibility and Efficacy of Exercise Training Concomitant with Re-Assessment of Medical Therapy in Patients with Heart Failure Receiving Intravenous Inotropes

Exercise training in addition to re-assessment of medical treatments is recommended for patients with advanced heart failure. However, the feasibility and efficacy of exercise training in patients with heart failure receiving intravenous inotropes remains uncertain.Clinical data were analyzed from consecutive patients with stabilized hemodynamics receiving intravenous inotropes for more than 1 week and undergoing cardiac rehabilitation at our institute between February 2020 and May 2022. All patients received re-assessment of guideline-directed medical therapy and non-pharmacological treatment, in addition to the exercise therapy. The intensity of exercise training was determined based on the results of cardiopulmonary exercise testing.A total of 10 patients receiving intravenous inotropes (median age 60 years, left ventricular ejection fraction 23%) were included. All patients received low-dose dobutamine and 4 patients received concomitant milrinone. Exercise training was continued for 112 days on median without any critical complications. Intravenous inotropes were continued for 41 days on median and weaned off in all patients. Plasma B-type natriuretic peptide decreased slightly from 291 (129, 526) to 177 (54, 278) pg/mL (P = 0.070) and peak oxygen consumption increased from 10.0 (8.3, 15.3) to 15.2 (10.9, 17.2) mL/kg/minute (P = 0.142) during the 6-month observational period following the initiation of exercise intervention.Exercise training might be feasible and effective in patients with advanced heart failure receiving low-dose intravenous inotrope support concomitant with re-assessment of medical treatment.

Glucose-Induced Hemodynamic and Metabolic Response of Skeletal Muscle in Heart Failure Patients with Reduced vs. Preserved Ejection Fraction-A Pilot Study

(1) Background: Insulin resistance (IR) is a characteristic pathophysiologic feature in heart failure (HF). We tested the hypothesis that skeletal muscle metabolism is differently impaired in patients with reduced (HFrEF) vs. preserved (HFpEF) ejection fraction. (2) Methods: carbohydrate and lipid metabolism was studied in situ by intramuscular microdialysis in patients with HFrEF (59 ± 14y, NYHA I-III) and HFpEF (65 ± 10y, NYHA I-II) vs. healthy subjects of similar age during the oral glucose load (oGL); (3) Results: There were no difference in fasting serum and interstitial parameters between the groups. Blood and dialysate glucose increased significantly in HFpEF vs. HFrEF and controls upon oGT (both p < 0.0001), while insulin increased significantly in HFrEF vs. HFpEF and controls (p < 0.0005). Muscle tissue perfusion tended to be lower in HFrEF vs. HFpEF and controls after the oGL (p = 0.057). There were no differences in postprandial increases in dialysate lactate and pyruvate. Postprandial dialysate glycerol was higher in HFpEF vs. HFrEF and controls upon oGL (p = 0.0016); (4) Conclusion: A pattern of muscle glucose metabolism is distinctly different in patients with HFrEF vs. HFpEF. While postprandial IR was characterized by impaired tissue perfusion and higher compensatory insulin secretion in HFrEF, reduced muscle glucose uptake and a blunted antilipolytic effect of insulin were found in HFpEF.

Automated digital counselling with social network support as a novel intervention for patients with heart failure: protocol for randomised controlled trial

INTRODUCTION

Heart failure (HF) symptoms improve through self-care, for which adherence remains low among patients despite the provision of education for these behaviours by clinical teams. Open Access Digital Community Promoting Self-Care, Peer Support and Health Literacy (ODYSSEE-vCHAT) combines automated digital counselling with social network support to improve mortality and morbidity, engagement with self-care materials, and health-related quality of life.

METHODS AND ANALYSIS

Use of ODYSSEE-vCHAT via Internet-connected personal computer by 162 HF patients will be compared with a control condition over 22 months. The primary outcome is a composite index score of all-cause mortality, all-cause emergency department visits, and HF-related hospitalisation at trial completion. Secondary outcomes include individual components of the composite index, engagement with self-care materials, and patient-reported measures of physical and psychosocial well-being, disease management, health literacy, and substance use. Patients are recruited from tertiary care hospitals in Toronto, Canada and randomised on a 1:1 ratio to both arms of the trial. Online assessments occur at baseline (t=0), months 4, 8 and 12, and trial completion. Ordinal logistic regression analyses and generalised linear models will evaluate primary and secondary outcomes.

ETHICS AND DISSEMINATION

The trial has been approved by the research ethics boards at the University Health Network (20-5960), Sunnybrook Hospital (5117), and Mount Sinai Hospital (21-022-E). Informed consent of eligible patients occurs in person or online. Findings will be shared with key stakeholders and the public. Results will allow for the preparation of a Canada-wide phase III trial to evaluate the efficacy of ODYSSEE-vCHAT in improving clinical outcomes and raising the standard of outpatient care.

TRIAL REGISTRATION NUMBER

NCT04966104.

Cardiopulmonary exercise responses in patients with non-ischemic heart failure and a mildly reduced ejection fraction

Background: The cardiopulmonary response to exercise in patients with heart failure exhibiting a mildly reduced ejection fraction (41% ≤ EF ≤ 49%) remains unclear. Materials & methods: A total of 193 consecutive patients with heart failure (excluding those with coronary artery disease) who underwent cardiopulmonary exercise (CPX) tests were examined. CPX variables were compared among patients with reduced, mildly reduced, and preserved EF. Results: The CPX test responses of patients with mildly reduced EF were similar to those of patients with reduced or preserved EF; however, increases in systolic blood pressure during exercise differed significantly (32 ± 26, 50 ± 24, and 41 ± 31 mmHg, respectively; p = 0.016). Grip strength and an increase in systolic blood pressure during exercise were independently associated with peak oxygen uptake in patients with mildly reduced EF (β = 0.41, 0.35, respectively; p < 0.05). Conclusion: Measurements of grip strength and blood pressure during exercise are useful predictors of prognoses in patients with non-ischemic and mildly reduced EF.

Neuregulin (NRG-1β) Is Pro-Myogenic and Anti-Cachectic in Respiratory Muscles of Post-Myocardial Infarcted Swine

Neuregulin-1β (NRG-1β) is a growth and differentiation factor with pleiotropic systemic effects. Because NRG-1β has therapeutic potential for heart failure and has known growth effects in skeletal muscle, we hypothesized that it might affect heart failure-associated cachexia, a severe co-morbidity characterized by a loss of muscle mass. We therefore assessed NRG-1β's effect on intercostal skeletal muscle gene expression in a swine model of heart failure using recombinant glial growth factor 2 (USAN-cimaglermin alfa), a version of NRG-1β that has been tested in humans with systolic heart failure. Animals received one of two intravenous doses (0.67 or 2 mg/kg) of NRG-1β bi-weekly for 4 weeks, beginning one week after infarct. Based on paired-end RNA sequencing, NRG-1β treatment altered the intercostal muscle gene expression of 581 transcripts, including genes required for myofiber growth, maintenance and survival, such as MYH3, MYHC, MYL6B, KY and HES1. Importantly, NRG-1β altered the directionality of at least 85 genes associated with cachexia, including myostatin, which negatively regulates myoblast differentiation by down-regulating MyoD expression. Consistent with this, MyoD was increased in NRG-1β-treated animals. In vitro experiments with myoblast cell lines confirmed that NRG-1β induces ERBB-dependent differentiation. These findings suggest a NRG-1β-mediated anti-atrophic, anti-cachexia effect that may provide additional benefits to this potential therapy in heart failure.

Validity of anaerobic threshold measured in resistance exercise

[Purpose] Intensity for resistance exercise is estimated based on the maximum muscle strength. Exercise prescription without evaluating the biological response has a challenge. This study aimed to confirm whether anaerobic threshold measured using cardiopulmonary exercise test in resistance exercise is appropriate or not. [Participants and Methods] Resistance exercise adopted for the study was right-leg knee extension. The participants were 10 healthy young males. We investigated whether the oxygen uptake kinetics achieved a steady state within 3 min during the constant-load test with knee extension at 80% anaerobic threshold using cardiopulmonary exercise test with knee extension. If oxygen uptake kinetics achieved a steady state within 3 min, the exercise intensity measured using cardiopulmonary exercise test was considered appropriate. [Results] Anaerobic threshold was measured using the conventional approach in all participants. The steady state of oxygen uptake kinetics could be achieved within 3 min. In the constant-load test with knee extension at 80% anaerobic threshold, the oxygen uptake kinetics achieved a steady state within 3 min. [Conclusion] Based on the findings, the anaerobic threshold obtained using cardiopulmonary exercise test with resistance exercise was judged as appropriate. The results of this study contribute to the accurate setting of exercise load for resistance exercise and condition setting for the evaluation of skeletal muscle function.

Treatments for skeletal muscle abnormalities in heart failure: sodium-glucose transporter 2 and ketone bodies

Various skeletal muscle abnormalities are known to occur in heart failure (HF), and are closely associated with exercise intolerance. Particularly, abnormal energy metabolism caused by mitochondrial dysfunction in skeletal muscle is a cause of decreased endurance exercise capacity. However, to date, no specific drug treatment has been established for the skeletal muscle abnormalities and exercise intolerance occurring in HF patients. Sodium-glucose transporter 2 (SGLT2) inhibitors promote glucose excretion by suppressing glucose reabsorption in the renal tubules, which has a hypoglycemic effect independent of insulin secretion. Recently, large clinical trials have demonstrated that treatment with SGLT2 inhibitors suppresses cardiovascular events in patients who have HF with systolic dysfunction. Mechanisms of the therapeutic effects of SGLT2 inhibitors for HF have been suggested to be diuretic, suppression of neurohumoral factor activation, renal protection, and improvement of myocardial metabolism, but has not been clarified to date. SGLT2 inhibitors are known to increase blood ketone bodies. This suggests that they may improve the abnormal skeletal muscle metabolism in HF, i.e., improve fatty acid metabolism, suppress glycolysis, and utilize ketone bodies in mitochondrial energy production. Ultimately, they may improve aerobic metabolism in skeletal muscle, and suppress anaerobic metabolism and improve aerobic exercise capacity at the level of the anaerobic threshold. The potential actions of such SGLT2 inhibitors explain their effectiveness in HF, and may be candidates for new drug treatments aimed at improving exercise intolerance. In this review, we outlined the effects of SGLT2 inhibitors on skeletal muscle metabolism, with a particular focus on ketone metabolism.

Role of systemic inflammation in functional recovery, dysphagia, and 1-y mortality in heart failure: A prospective cohort study

OBJECTIVES

This study evaluated the relationship between systemic inflammation and clinical outcomes in people hospitalized with acute heart failure (AHF).

METHODS

We prospectively enrolled people newly hospitalized with AHF after excluding those with concomitant infectious or inflammatory diseases. Systemic inflammation was evaluated using the modified Glasgow Prognostic Score (mGPS) at hospitalization, and participants were classified into low-grade and high-grade inflammation groups (mGPS 0-1 and 2, respectively). The primary outcome measure was functional recovery, evaluated using the Barthel Index gain. Secondary outcome measures were dysphagia at discharge and all-cause 1-y mortality after discharge. Multivariable analyses and Kaplan-Meier estimates were used to determine the association between systemic inflammation and study outcomes.

RESULTS

A total of 184 participants (mean age, 79.1 y; 48.4% female, 51.6% male) were included; 148 (80.4%) and 36 (19.6%), respectively, had low-grade and high-grade inflammation. Participants with high-grade inflammation were significantly older, had lower body mass index and muscle strength, and had lower nutrient intake, swallowing status, and Barthel Index than those with low-grade inflammation. In multivariable analyses, mGPS was significantly associated with Barthel Index gain (β = -0.229, P = 0.004) and Food Intake Level Scale (odds ratio = 5.067, P = 0.034) at discharge; mGPS was associated with 1-y mortality after discharge (P = 0.003).

CONCLUSIONS

Baseline systemic inflammation was negatively associated with improvements in physical function and dysphagia and with 1-y survival in people with AHF. These findings highlight the importance of focusing on the assessment of systemic inflammation to accurately predict the functional prognosis of people with AHF.

Physical Activity in the Treatment and Prevention of Heart Failure: An Update

ABSTRACT

Heart failure (HF) is a complex clinical syndrome hallmarked by an inability to match cardiac output with metabolic demand, resulting in exercise intolerance. HF is increasingly prevalent in an aging population and accounts for substantial burden of health care costs and morbidity. Because many of the central and peripheral mechanisms of HF respond favorably to exercise training, its role in HF treatment is becoming established. The role of habitual physical activity in the primary prevention of HF is less clear; however, available evidence is supportive. This article reviews recently published studies on exercise training and usual physical activity in HF treatment and prevention, discusses potential mechanisms, and suggests areas where further research is needed.

Does renin-angiotensin system inhibition have impacts on muscle mass and bone mineral density in heart failure patients?

Aims

Results of experimental studies have indicated the possibility of muscle and bone mass being negatively regulated by renin‐angiotensin system (RAS) activation, but that possibility has not been analysed in patients with heart failure (HF).

Methods and results

Data for HF patients who received a dual‐energy X‐ray absorptiometry scan in our hospital were reviewed. Propensity scores for the use of RAS inhibitors (RASIs) were calculated using a multivariate logistic regression model to minimize selection bias. One hundred sixty pairs of patients were extracted. Plasma aldosterone concentration was significantly lower in the RASIs group than in the no‐RASIs group (119 [IQR 71–185] vs. 94 [IQR 60–131] pg/mL, P = 0.003), confirming RAS inhibition in the RASIs group. Skeletal muscle mass index tended to be higher in the RASIs group than in the non‐RASIs group (15.6 [IQR 14.0–17.2] vs. 15.0 [IQR 13.3–16.6] pg/mL, P = 0.065). The proportion of patients with muscle wasting, defined as appendicular skeletal muscle mass indexes of <7.00 and <5.40 kg/m² for males and females, respectively, was significantly lower in the RASIs group than in the non‐RASIs group (53% vs. 64%, P = 0.041). Multivariate logistic regression analysis showed that the no use of RASIs was associated with presence of muscle wasting independently of age, presence of diabetes, renal function, and severity of HF. Bone mineral densities and proportions of patients with osteoporosis were similar in the two groups.

Conclusions

Renin‐angiotensin system inhibition is associated with a lower prevalence of muscle wasting in HF patients independently of established risk factors.

Heart Failure-Induced Skeletal Muscle Wasting

PURPOSE OF REVIEW

Heart failure (HF) is a structural or functional cardiac abnormality which leads to failure of the heart to deliver oxygen commensurately with the requirements of the tissues and it may progress to a generalized wasting of skeletal muscle, fat tissue, and bone tissue (cardiac cachexia). Clinically, dyspnea, fatigue, and exercise intolerance are some typical signs and symptoms that characterize HF patients. This review focused on the phenotypic characteristics of HF-induced skeletal myopathy as well as the mechanisms of muscle wasting due to HF and highlighted possible therapeutic strategies for skeletal muscle wasting in HF.

RECENT FINDINGS

The impaired exercise capacity of those patients is not attributed to the reduced blood flow in the exercising muscles, but rather to abnormal metabolic responses, myocyte apoptosis and atrophy of skeletal muscle. Specifically, the development of skeletal muscle wasting in chronic HF is characterized by structural, metabolic, and functional abnormalities in skeletal muscle and may be a result not only of reduced physical activity, but also of metabolic or hormonal derangements that favour catabolism over anabolism. In particular, abnormal energy metabolism, mitochondrial dysfunction, transition of myofibers from type I to type II, muscle atrophy, and reduction in muscular strength are included in skeletal muscle abnormalities which play a central role in the decreased exercise capacity of HF patients. Skeletal muscle alterations and exercise intolerance observed in HF are reversible by exercise training, since it is the only demonstrated intervention able to improve skeletal muscle metabolism, growth factor activity, and functional capacity and to reverse peripheral abnormalities.

Mid-arm muscle circumference as an indicator of exercise tolerance in chronic heart failure

AIM

Skeletal muscle mass is associated with exercise tolerance in patients with chronic heart failure (CHF). Anthropometric indicators are used to evaluate skeletal muscle mass, as these can be easily assessed in clinical practice. However, the association between anthropometric indicators and exercise tolerance is unclear. This study aimed to investigate the association between anthropometric indicators and exercise tolerance in CHF patients.

METHODS

We evaluated 69 patients with CHF. Mid-arm circumference, mid-arm muscle circumference (MAMC), calf circumference and body mass index were measured as the anthropometric indicators. Exercise tolerance was evaluated according to the peak oxygen uptake (VO₂ ). Correlation analyses were carried out to determine the association between peak VO₂ and anthropometric indicators. Furthermore, univariate and multiple regression analyses were carried out using peak VO₂ as the dependent variable, and age, male, left ventricular ejection fraction, angiotensin II receptor blocker or angiotensin converting enzyme inhibitor, diuretics, B-type natriuretic peptide, estimated glomerular filtration rate, hemoglobin and anthropometric indicators as the independent variables.

RESULTS

There were significant positive correlations between the peak VO₂ and mid-arm circumference (r_s = 0.378, P = 0.001), MAMC (r = 0.634, P < 0.001) and calf circumference (r = 0.292, P = 0.015). In multiple regression analysis, MAMC (β = 0.721, P < 0.001) and estimated glomerular filtration rate (β = 0.279, P = 0.007) were independent factors associated with peak VO₂ .

CONCLUSIONS

MAMC is independently associated with peak VO₂ in CHF patients. Thus, MAMC could be an indicator of exercise tolerance, which is closely related to the severity and prognosis of CHF. Geriatr Gerontol Int 2021; 21: 411-415.

Inhibition of xanthine oxidase in the acute phase of myocardial infarction prevents skeletal muscle abnormalities and exercise intolerance

AIMS

Exercise intolerance in patients with heart failure (HF) is partly attributed to skeletal muscle abnormalities. We have shown that reactive oxygen species (ROS) play a crucial role in skeletal muscle abnormalities, but the pathogenic mechanism remains unclear. Xanthine oxidase (XO) is reported to be an important mediator of ROS overproduction in ischaemic tissue. Here, we tested the hypothesis that skeletal muscle abnormalities in HF are initially caused by XO-derived ROS and are prevented by the inhibition of their production.

METHODS AND RESULTS

Myocardial infarction (MI) was induced in male C57BL/6J mice, which eventually led to HF, and a sham operation was performed in control mice. The time course of XO-derived ROS production in mouse skeletal muscle post-MI was first analysed. XO-derived ROS production was significantly increased in MI mice from Days 1 to 3 post-surgery (acute phase), whereas it did not differ between the MI and sham groups from 7 to 28 days (chronic phase). Second, mice were divided into three groups: sham + vehicle (Sham + Veh), MI + vehicle (MI + Veh), and MI + febuxostat (an XO inhibitor, 5 mg/kg body weight/day; MI + Feb). Febuxostat or vehicle was administered at 1 and 24 h before surgery, and once-daily on Days 1-7 post-surgery. On Day 28 post-surgery, exercise capacity and mitochondrial respiration in skeletal muscle fibres were significantly decreased in MI + Veh compared with Sham + Veh mice. An increase in damaged mitochondria in MI + Veh compared with Sham + Veh mice was also observed. The wet weight and cross-sectional area of slow muscle fibres (higher XO-derived ROS) was reduced via the down-regulation of protein synthesis-associated mTOR-p70S6K signalling in MI + Veh compared with Sham + Veh mice. These impairments were ameliorated in MI + Feb mice, in association with a reduction of XO-derived ROS production, without affecting cardiac function.

CONCLUSION

XO inhibition during the acute phase post-MI can prevent skeletal muscle abnormalities and exercise intolerance in mice with HF.

Skeletal muscle atrophy in heart failure with diabetes: from molecular mechanisms to clinical evidence

Two highly prevalent and growing global diseases impacted by skeletal muscle atrophy are chronic heart failure (HF) and type 2 diabetes mellitus (DM). The presence of either condition increases the likelihood of developing the other, with recent studies revealing a large and relatively poorly characterized clinical population of patients with coexistent HF and DM (HFDM). HFDM results in worse symptoms and poorer clinical outcomes compared with DM or HF alone, and cardiovascular-focused disease-modifying agents have proven less effective in HFDM indicating a key role of the periphery. This review combines current clinical knowledge and basic biological mechanisms to address the critical emergence of skeletal muscle atrophy in patients with HFDM as a key driver of symptoms. We discuss how the degree of skeletal muscle wasting in patients with HFDM is likely underpinned by a variety of mechanisms that include mitochondrial dysfunction, insulin resistance, inflammation, and lipotoxicity. Given many atrophic triggers (e.g. ubiquitin proteasome/autophagy/calpain activity and supressed IGF1-Akt-mTORC1 signalling) are linked to increased production of reactive oxygen species, we speculate that a higher pro-oxidative state in HFDM could be a unifying mechanism that promotes accelerated fibre atrophy. Overall, our proposal is that patients with HFDM represent a unique clinical population, prompting a review of treatment strategies including further focus on elucidating potential mechanisms and therapeutic targets of muscle atrophy in these distinct patients.

Senescence Is Associated With Elevated Intracellular Resting [Ca2 +] in Mice Skeletal Muscle Fibers. An in vivo Study

Aging causes skeletal muscles to become atrophied, weak, and easily fatigued. Here, we have tested the hypothesis that normal aging in skeletal muscle cells is associated with Ca²⁺ intracellular dyshomeostasis and oxidative stress. Intracellular Ca²⁺ concentration ([Ca²⁺]_i), resting intracellular Na⁺ concentration ([Na⁺]_i) and reactive oxygen species (ROS) production were measured in vivo (superficial gastrocnemius fibers) using double-barreled ion-selective microelectrodes, and in vitro [isolated single flexor digitorum brevis fibers] using fluorescent ROS sensor CM-H2DCFDA in young (3 months of age), middle-aged (12 months of age), and aged (24 months of age) mice. We found an age-related increase in [Ca²⁺]_i from 121 ± 4 nM in young muscle cells which rose to 255 ± 36 nM in middle-aged and to 409 ± 25 nM in aged cells. [Na⁺]_i also showed an age-dependent elevation, increasing from 8 ± 0.5 mM in young muscle fibers, to 12 ± 1 mM in middle-aged and to 17 ± 1 mM in old muscle fibers. Using the fluorescent ROS sensor CM-H2DCFDA we found that these increases in intracellular cation concentrations were associated with significantly increased basal ROS production as demonstrated by age related increases in the rate of dichlorodihydrofluorescein fluorescence. To determine is this could be modified by reducing ROS and/or blocking sarcolemmal Ca²⁺ influx we administered flufenamic acid (FFA), a non-steroidal anti-inflammatory drug which is also a non-selective blocker of the transient receptor potential canonical channels (TRPCs), for 4 weeks to determine if this would have a beneficial effect. FFA treatment reduced both basal ROS production and muscle [Ca²⁺]_i and [Na⁺]_i in middle-aged and aged muscle fibers compared to fibers and muscles of untreated 12 and 24-months old mice. [Ca²⁺]_i was reduced to 134 ± 8 nM in middle-aged muscle and to 246 ± 40 nM in muscle from aged mice. Likewise [Na⁺]_i was reduced to 9 ± 0.7 mM in middle-aged muscles and to 13 ± 1 mM in muscle from aged mice. FFA treatment also reduced age associated increases in plasma interleukin 6 and tumor necrosis factor-alpha (TNF-α) concentrations which were elevated in 12 and 24-months old mice compared to young mice and decreased age-related muscle damage as indicated by a reduction in serum creatine kinase (CK) activity. Our data provides a direct demonstration that normal aging is associated with a significant elevation [Ca²⁺]_i, [Na⁺]_i, and intracellular ROS production in skeletal muscle fibers. Furthermore, the fact that FFA reduced the intracellular [Ca²⁺], [Na⁺], and ROS production as well as the elevated IL6, TNF-α, and CK levels, led us to suggest that its pharmacological effect may be related to its action both as a TRPC channel blocker and as an anti-inflammatory.

Frailty, sarcopenia and cachexia in heart failure patients: Different clinical entities of the same painting

Heart Failure (HF) in elderly patients is a systemic syndrome where advanced age, comorbidities with organ system deterioration, frailty and impaired cognition significantly impact outcome. Cardiac cachexia, sarcopenia and frailty despite overlap in definitions are different clinical entities that frequently coexist in HF patients. However, these co-factors often remain unaddressed, resulting in poor quality-of-life, prolonged physical disability and exercise intolerance and finally with higher rehospitalization rates and mortality. Strategy aim to increase muscle mass and muscle strength and delay the occurrence of frailty state appear essential in this regard. Common HF drugs therapy (b-blockers, angiotensin-converting enzyme inhibitors) and prescription of physical exercise program remain the cornerstone of therapeutic approach in HF patients with new promising data regarding nutritional supplementation. However, the treatment of all these conditions still remain debated and only a profound knowledge of the specific mechanisms and patterns of disease progression will allow to use the appropriate therapy in a given clinical setting. For all these reasons we briefly review current knowledge on frailty, sarcopenia and cachexia in HF patients with the attempt to define clinically significant degrees of multiorgan dysfunction, specific "red alert" thresholds in clinical practice and therapeutic approach.

Distinct determinants of muscle wasting in nonobese heart failure patients with and without type 2 diabetes mellitus

BACKGROUND

Muscle wasting, that is, reduction in muscle mass, is frequently observed in patients with chronic heart failure (CHF) and diabetes mellitus (DM).

METHODS

We retrospectively examined 185 patients with CHF (median age of 71 years [interquartile range, 61-78 years]; 64% male) who received a dual-energy X-ray absorptiometry scan for assessment of appendicular skeletal muscle mass index (ASMI).

RESULTS

Seventy patients with CHF (38%) had DM. Patients with DM had higher prevalences of ischemic heart disease and hypertension, lower levels of estimated glomerular filtration rate (eGFR) and ASMI, and higher levels of plasma renin activity (PRA) than did patients without DM. In simple regression analyses, ASMI was positively correlated with the Mini Nutritional Assessment Short Form (MNA-SF) score and levels of hemoglobin, eGFR, and fasting plasma insulin and was negatively correlated with levels of N-terminal pro B-type natriuretic peptide, PRA, and cortisol. In multiple linear regression analyses, age, MNA-SF score, DM, fasting plasma insulin level, and PRA were independently associated with ASMI. When multiple linear regression analyses were separately performed in a non-DM group and a DM group, MNA-SF score and fasting plasma insulin level were independent variables for ASMI in both groups. PRA was independently associated with ASMI in the DM group but not in the non-DM group, whereas cortisol concentration was independently associated with ASMI only in the non-DM group.

CONCLUSIONS

In addition to malnutrition and reduction in plasma insulin, renin-angiotensin system activation may be responsible for the development of muscle wasting in CHF patients with DM.

Brain-Derived Neurotrophic Factor Improves Impaired Fatty Acid Oxidation Via the Activation of Adenosine Monophosphate-Activated Protein Kinase-ɑ - Proliferator-Activated Receptor-r Coactivator-1ɑ Signaling in Skeletal Muscle of Mice With Heart Failure

BACKGROUND

We recently reported that treatment with rhBDNF (recombinant human brain-derived neurotrophic factor) improved the reduced exercise capacity of mice with heart failure (HF) after myocardial infarction (MI). Since BDNF is reported to enhance fatty acid oxidation, we herein conducted an in vivo investigation to determine whether the improvement in exercise capacity is due to the enhancement of the fatty acid oxidation of skeletal muscle via the AMPKα-PGC1α (adenosine monophosphate-activated protein kinase-ɑ-proliferator-activated receptor-r coactivator-1ɑ) axis.

METHODS

MI and sham operations were conducted in C57BL/6J mice. Two weeks postsurgery, we randomly divided the MI mice into groups treated with rhBDNF or vehicle for 2 weeks. AMPKα-PGC1α signaling and mitochondrial content in the skeletal muscle of the mice were evaluated by Western blotting and transmission electron microscopy. Fatty acid β-oxidation was examined by high-resolution respirometry using permeabilized muscle fiber. BDNF-knockout mice were treated with 5-aminoimidazole-4-carboxamide-1-beta-d-riboruranoside, an activator of AMPK.

RESULTS

The rhBDNF treatment significantly increased the expressions of phosphorylated AMPKα and PGC1α protein and the intermyofibrillar mitochondrial density in the MI mice. The lowered skeletal muscle mitochondrial fatty acid oxidation was significantly improved in the rhBDNF-treated MI mice. The reduced exercise capacity and mitochondrial dysfunction of the BDNF-knockout mice were improved by 5-aminoimidazole-4-carboxamide-1-beta-d-riboruranoside.

CONCLUSIONS

Beneficial effects of BDNF on the exercise capacity of mice with HF are mediated through an enhancement of fatty acid oxidation via the activation of AMPKα-PGC1α in skeletal muscle. BDNF may become a therapeutic option to improve exercise capacity as an alternative or adjunct to exercise training.

Physical functional performance and prognosis in patients with heart failure: a systematic review and meta-analysis

BACKGROUND

Patients with Heart Failure (HF) show impaired functional capacities which have been related to their prognosis. Moreover, physical functional performance in functional tests has also been related to the prognosis in patients with HF. Thus, it would be useful to investigate how physical functional performance in functional tests could determine the prognosis in patients with HF, because HF is the leading cause of hospital admissions for people older than 65 years old. This systematic review and meta-analysis aims to summarise and synthesise the evidence published about the relationship between physical functional performance and prognosis in patients with HF, as well as assess the risk of bias of included studies and the level of evidence per outcome.

METHODS

Major electronic databases, such as PubMed, AMED, CINAHL, EMBASE, PEDro, Web of Science, were searched from inception to March 2020 for observational longitudinal cohort studies (prospective or retrospective) examining the relationship between physical functional performance and prognosis in patients with HF.

RESULTS

44 observational longitudinal cohort studies with a total of 22,598 patients with HF were included. 26 included studies reported a low risk of bias, and 17 included studies showed a moderate risk of bias. Patients with poor physical functional performance in the Six Minute Walking Test (6MWT), in the Short Physical Performance Battery (SPPB) and in the Gait Speed Test showed worse prognosis in terms of larger risk of hospitalisation or mortality than patients with good physical functional performance. However, there was a lack of homogeneity regarding which cut-off points should be used to stratify patients with poor physical functional performance from patients with good physical functional performance.

CONCLUSION

The review includes a large number of studies which show a strong relationship between physical functional performance and prognosis in patients with HF. Most of the included studies reported a low risk of bias, and GRADE criteria showed a low and a moderate level of evidence per outcome.

Impact of Mitophagy and Mitochondrial Unfolded Protein Response as New Adaptive Mechanisms Underlying Old Pathologies: Sarcopenia and Non-Alcoholic Fatty Liver Disease

Mitochondria are the first-line defense of the cell in the presence of stressing processes that can induce mitochondrial dysfunction. Under these conditions, the activation of two axes is accomplished, namely, (i) the mitochondrial unfolded protein response (UPRmt) to promote cell recovery and survival of the mitochondrial network; (ii) the mitophagy process to eliminate altered or dysfunctional mitochondria. For these purposes, the former response induces the expression of chaperones, proteases, antioxidant components and protein import and assembly factors, whereas the latter is signaled through the activation of the PINK1/Parkin and BNIP3/NIX pathways. These adaptive mechanisms may be compromised during aging, leading to the development of several pathologies including sarcopenia, defined as the loss of skeletal muscle mass and performance; and non-alcoholic fatty liver disease (NAFLD). These age-associated diseases are characterized by the progressive loss of organ function due to the accumulation of reactive oxygen species (ROS)-induced damage to biomolecules, since the ability to counteract the continuous and large generation of ROS becomes increasingly inefficient with aging, resulting in mitochondrial dysfunction as a central pathogenic mechanism. Nevertheless, the role of the integrated stress response (ISR) involving UPRmt and mitophagy in the development and progression of these illnesses is still a matter of debate, considering that some studies indicate that the prolonged exposure to low levels of stress may trigger these mechanisms to maintain mitohormesis, whereas others sustain that chronic activation of them could lead to cell death. In this review, we discuss the available research that contributes to unveil the role of the mitochondrial UPR in the development of sarcopenia, in an attempt to describe changes prior to the manifestation of severe symptoms; and in NAFLD, in order to prevent or reverse fat accumulation and its progression by means of suitable protocols to be addressed in future studies.

Examination of independent predictors of discharge disposition in acute phase hospitalized heart failure patients undergoing phase I cardiac rehabilitation

BACKGROUND

Increasing acute heart failure (HF) population is very common. Discharge disposition is one of the major cardiac rehabilitation (CR) outcomes. However, there were few data exist on home discharge criteria in acute phase HF patients who were underwent CR.

AIM

The aim of this study was to clarify the predictors of home discharge in acute phase hospitalized HF patients who were underwent guideline-based CR.

DESIGN

The study was designed as an intervention study.

SETTING

This study took place in acute-hospital setting.

POPULATION

Participants were 320 hospitalized acute phase HF patients who were underwent Japanese guideline-based CR.

METHODS

Knee extension strength (KES), exercise tolerance, short physical performance battery (SPPB), Barthel Index (BI), mini-mental state examination (MMSE) and controlling nutritional status (CONUT) were evaluated on hospital admission and at hospital discharge, respectively. At hospital discharge, patients were divided into the home group (N.=255) and the non-home group (N.=65) based on discharge disposition. The independent predictors of home discharge and cut-off value were evaluated using logistic regression analysis and receiver operating curve.

RESULTS

At the time of hospital admission, KES, exercise tolerance, SPPB, BI and MMSE is significantly higher in the home group. However, there were no significant differences in HF severity and CONUT on hospital admission between the groups. At hospital discharge, KES, exercise tolerance, SPPB, BI and MMSE were significantly higher and CONUT was significantly lower in the home group than in the non-home group. Multivariate analysis showed KES and SPPB on hospital admission, length of hospital stay and BI at hospital discharge were the independent predictors of home discharge. Cut-off values for predicting home discharge were KES on hospital admission ≥12.1 kg, SPPB on hospital admission ≥3 points, and BI at hospital discharge ≥80 points.

CONCLUSIONS

The present study suggested that KES and SPPB on hospital admission may contributed to early detection of the patients who are difficult to return home. Additionally, there is a possibility that CR goal setting of BI ≥80 points is effective to home discharge in acute phase hospitalized HF patients.

CLINICAL REHABILITATION IMPACT

This study may contribute to early detection of the patients who are predicted to be difficult to return home and to appropriate rehabilitation goals setting.

Physical Function and Cardio-Ankle Vascular Index in Elderly Heart Failure Patients

The number of heart failure patients is increasing rapidly in Japan because of its large elderly population. As age increases, arterial stiffness and physical dysfunction progress. This study aimed to evaluate the association between the physical function and arterial stiffness in elderly heart failure patients.This retrospective, observational study includes data from 100 heart failure patients aged ≥ 65 years who were admitted to our hospital and underwent cardiac rehabilitation. The Cardio-Ankle Vascular Index (CAVI) was measured as an indicator of arterial stiffness. Body composition was assessed by bioelectrical impedance analysis. To determine the degree of physical function, we assessed handgrip strength, five-meter walk speed (5MWS), five-repetition sit-to-stand time (5RSST) and six-minute walk distance (6MWD). Sarcopenia was defined using Asian guidelines based on physical function and body composition.Among 100 patients, 47.0% of patients had sarcopenia. After adjustments for age, sex, atrial fibrillation, and ischemic cardiomyopathy, CAVI was significantly higher in with sarcopenia patients than those without sarcopenia. Age, handgrip strength, 5MWS, 5RSST, and 6MWD were associated with CAVI, and 6MWD was as an independent determinant factor of CAVI.6MWD was recognized as an accurate physical function indicator. These findings suggested that physical function and arterial stiffness complement each other. To restore cardiac dysfunction, improving both arterial stiffness and physical function might be useful.

Abnormalities of Skeletal Muscle, Adipocyte Tissue, and Lipid Metabolism in Heart Failure: Practical Therapeutic Targets

Chronic diseases, including heart failure (HF), are often accompanied with skeletal muscle abnormalities in both quality and quantity, which are the major cause of impairment of the activities of daily living and quality of life. We have shown that skeletal muscle abnormalities are a hallmark of HF, in which metabolic pathways involving phosphocreatine and fatty acids are largely affected. Not only in HF, but the dysfunction of fatty acid metabolism may also occur in many chronic diseases, such as arteriosclerosis, as well as through insufficient physical exercise. Decreased fatty acid catabolism affects adenosine triphosphate (ATP) production in mitochondria, via decreased activity of the tricarboxylic acid cycle; and may cause abnormal accumulation of adipose tissue accompanied with hyperoxidation and ectopic lipid deposition. Such impairments of lipid metabolism are in turn detrimental to skeletal muscle, which is hence a chicken-and-egg problem between skeletal muscle and HF. In this review, we first discuss skeletal muscle abnormalities in HF, including sarcopenia; particularly their association with lipid metabolism and adipose tissue. On the other hand, the precise mechanisms involved in metabolic reprogramming and dysfunction are beginning to be understood, and an imbalance of daily nutritional intake of individuals has been found to be a causative factor for the development and worsening of HF. Physical exercise has long been known to be beneficial for the prevention and even treatment of HF. Again, the molecular mechanisms by which exercise promotes skeletal muscle as well as cardiac muscle functions are being clarified by recent studies. We propose that it is now the time to develop more “natural” methods to prevent and treat HF, rather than merely relying on drugs and medical interventions. Further analysis of the basic design of and molecular mechanisms involved in the human body, particularly the inextricable association between physical exercise and the integrity and functional plasticity of skeletal and cardiac muscles is required.

CRISPR/Cas9-Mediated miR-29b Editing as a Treatment of Different Types of Muscle Atrophy in Mice

Muscle atrophy is the loss of skeletal muscle mass and strength in response to diverse catabolic stimuli. At present, no effective treatments except exercise have been shown to reduce muscle atrophy clinically. Here, we report that CRISPR/Cas9-mediated genome editing through local injection into gastrocnemius muscles or tibialis anterior muscle efficiently targets the biogenesis processing sites in pre-miR-29b. In vivo, this CRISPR-based treatment prevented the muscle atrophy induced by angiotensin II (AngII), immobilization, and denervation via activation of the AKT-FOXO3A-mTOR signaling pathway and protected against AngII-induced myocyte apoptosis in mice, leading to significantly increased exercise capacity. Our work establishes CRISPR/Cas9-based gene targeting on miRNA as a potential durable therapy for the treatment of muscle atrophy and expands the strategies available interrogating miRNA function in vivo.

Angiotensin-converting-enzyme inhibitor prevents skeletal muscle fibrosis in myocardial infarction mice

BACKGROUND

Transforming growth factor beta (TGF-β)-Smad2/3 is the major signaling pathway of fibrosis, which is characterized by the excessive production and accumulation of extracellular matrix (ECM) components, including collagen. Although the ECM is an essential component of skeletal muscle, fibrosis may be harmful to muscle function. On the other hand, our previous studies have shown that levels of angiotensin II, which acts upstream of TGF-β-Smad2/3 signaling, is increased in mice with myocardial infarction (MI). In this study, we found higher skeletal muscle fibrosis in MI mice compared with control mice, and we investigated the mechanisms involved therein. Moreover, we administered an inhibitor based on the above mechanism and investigated its preventive effects on skeletal muscle fibrosis.

METHODS

Male C57BL/6 J mice with MI were created, and sham-operated mice were used as controls. The time course of skeletal muscle fibrosis post-MI was analyzed by picrosirius-red staining (days 1, 3, 7, and 14). Mice were then divided into 3 groups: sham + vehicle (Sham + Veh), MI + Veh, and MI + lisinopril (an angiotensin-converting enzyme [ACE] inhibitor, 20 mg/kg body weight/day in drinking water; MI + Lis). Lis or Veh was administered from immediately after the surgery to 14 days postsurgery.

RESULTS

Skeletal muscle fibrosis was significantly increased in MI mice compared with sham mice from 3 to 14 days postsurgery. Although mortality was lower in the MI + Lis mice than the MI + Veh mice, there was no difference in cardiac function between the 2 groups at 14 days. Skeletal muscle fibrosis and hydroxyproline (a key marker of collagen content) were significantly increased in MI + Veh mice compared with the Sham + Veh mice. Consistent with these results, protein expression of TGF-β and phosphorylated Smad2/3 in the skeletal muscle during the early time points after surgery (days 1-7 postsurgery) and blood angiotensin II at 14 days postsurgery was increased in MI mice compared with sham mice. These impairments were improved in MI + Lis mice, without any effects on spontaneous physical activity, muscle strength, muscle weight, and blood pressure.

CONCLUSIONS

ACE inhibitor administration prevents increased skeletal muscle fibrosis during the early phase after MI. Our findings indicate a new therapeutic target for ameliorating skeletal muscle abnormalities in heart diseases.

Knee extensor muscle strength as a predictor of peak oxygen uptake in patients with heart disease

[Purpose] The mortality rate increases when peak oxygen uptake is less than 5 metabolic equivalents, and peak oxygen uptake correlates with knee extensor muscle strength. This study aimed to determine the knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents. [Participants and Methods] We enrolled 45 consecutive patients (29 males and 16 females; average age, 63.6 ± 13.7 years) with heart disease receiving outpatient rehabilitation with us. We performed cardiopulmonary exercise testing with a bicycle ergometer to measure peak oxygen uptake. We investigated the relationship between peak oxygen uptake and isometric knee extensor muscle strength divided by the body weight (kgf/kg). The cutoff value for knee extensor muscle strength with peak oxygen uptake corresponding to 5 metabolic equivalents was calculated. [Results] Knee extensor muscle strength was significantly positively associated with peak oxygen uptake. The cutoff value for knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents was 0.46 kgf/kg. [Conclusion] In this study, the cutoff value for knee extensor muscle strength for achieving peak oxygen uptake corresponding to 5 metabolic equivalents in patients with heart disease was 0.46kgf/kg.