Skeletal myopathy in patients with chronic heart failure: significance of anabolic-androgenic hormones

Muscle wasting and cachexia in heart failure: mechanisms and therapies

Body wasting is a serious complication that affects a large proportion of patients with heart failure. Muscle wasting, also known as sarcopenia, is the loss of muscle mass and strength, whereas cachexia describes loss of weight. After reaching guideline-recommended doses of heart failure therapies, the most promising approach to treating body wasting seems to be combined therapy that includes exercise, nutritional counselling, and drug treatment. Nutritional considerations include avoiding excessive salt and fluid intake, and replenishment of deficiencies in trace elements. Administration of omega-3 polyunsaturated fatty acids is beneficial in selected patients. High-calorific nutritional supplements can also be useful. The prescription of aerobic exercise training that provokes mild or moderate breathlessness has good scientific support. Drugs with potential benefit in the treatment of body wasting that have been tested in clinical studies in patients with heart failure include testosterone, ghrelin, recombinant human growth hormone, essential amino acids, and β₂-adrenergic receptor agonists. In this Review, we summarize the pathophysiological mechanisms of muscle wasting and cachexia in heart failure, and highlight the potential treatment strategies. We aim to provide clinicians with the relevant information on body wasting to understand and treat these conditions in patients with heart failure.

Sarcopenia, cachexia, and muscle performance in heart failure: Review update 2016

Cachexia in the context of heart failure (HF) has been termed cardiac cachexia, and represents a progressive involuntary weight loss. Cachexia is mainly the result of an imbalance in the homeostasis of muscle protein synthesis and degradation due to a lower activity of protein synthesis pathways and an over-activation of protein degradation. In addition, muscle wasting leads to of impaired functional capacity, even after adjusting for clinical relevant variables in patients with HF. However, there is no sufficient therapeutic strategy in muscle wasting in HF patients and very few studies in animal models. Exercise training represents a promising intervention that can prevent or even reverse the process of muscle wasting, and worsening the muscle function and performance in HF with muscle wasting and cachexia. The pathological mechanisms and effective therapeutic approach of cardiac cachexia remain uncertain, because of the difficulty to establish animal cardiac cachexia models, thus novel animal models are warranted. Furthermore, the use of improved animal models will lead to a better understanding of the pathways that modulate muscle wasting and therapeutics of muscle wasting of cardiac cachexia.

Cardiac Cachexia: Perspectives for Prevention and Treatment

Cachexia is a prevalent pathological condition associated with chronic heart failure. Its occurrence predicts increased morbidity and mortality independent of important clinical variables such as age, ventricular function, or heart failure functional class. The clinical consequences of cachexia are dependent on both weight loss and systemic inflammation, which accompany cachexia development. Skeletal muscle wasting is an important component of cachexia; it often precedes cachexia development and predicts poor outcome in heart failure. Cachexia clinically affects several organs and systems. It is a multifactorial condition where underlying pathophysiological mechanisms are not completely understood making it difficult to develop specific prevention and treatment therapies. Preventive strategies have largely focused on muscle mass preservation. Different treatment options have been described, mostly in small clinical studies or experimental settings. These include nutritional support, neurohormonal blockade, reducing intestinal bacterial translocation, anemia and iron deficiency treatment, appetite stimulants, immunomodulatory agents, anabolic hormones, and physical exercise regimens. Currently, nonpharmacological therapy such as nutritional support and physical exercise are considered central to cachexia prevention and treatment.

Frailty and sarcopenia as the basis for the phenotypic manifestation of chronic diseases in older adults

Frailty is a functional status that precedes disability and is characterized by decreased functional reserve and increased vulnerability. In addition to disability, the frailty phenotype predicts falls, institutionalization, hospitalization and mortality. Frailty is the consequence of the interaction between the aging process and some chronic diseases and conditions that compromise functional systems and finally produce sarcopenia. Many of the clinical manifestations of frailty are explained by sarcopenia which is closely related to poor physical performance. Reduced regenerative capacity, malperfusion, oxidative stress, mitochondrial dysfunction and inflammation compose the sarcopenic skeletal muscle alterations associated to the frailty phenotype. Inflammation appears as a common determinant for chronic diseases, sarcopenia and frailty. The strategies to prevent the frailty phenotype include an adequate amount of physical activity and exercise as well as pharmacological interventions such as myostatin inhibitors and specific androgen receptor modulators. Cell response to stress pathways such as Nrf2, sirtuins and klotho could be considered as future therapeutic interventions for the management of frailty phenotype and aging-related chronic diseases.

Cardiac cachexia: hic et nunc

Cardiac cachexia (CC) is the clinical entity at the end of the chronic natural course of heart failure (HF). Despite the efforts, even the most recent definition of cardiac cachexia has been challenged, more precisely, the addition of new criteria on top of obligatory weight loss. The pathophysiology of CC is complex and multifactorial. A better understanding of pathophysiological pathways in body wasting will contribute to establish potentially novel treatment strategies. The complex biochemical network related with CC and HF pathophysiology underlines that a single biomarker cannot reflect all of the features of the disease. Biomarkers that could pick up the changes in body composition before they convey into clinical manifestations of CC would be of great importance. The development of preventive and therapeutic strategies against cachexia, sarcopenia, and wasting disorders is perceived as an urgent need by healthcare professionals. The treatment of body wasting remains an unresolved challenge to this day. As CC is a multifactorial disorder, it is unlikely that any single agent will be completely effective in treating this condition. Among all investigated therapeutic strategies, aerobic exercise training in HF patients is the most proved to counteract skeletal muscle wasting and is recommended by treatment guidelines for HF.

Effects of intravenous iron therapy in iron-deficient patients with systolic heart failure: a meta-analysis of randomized controlled trials

AIMS

The aim of this study was to assess the net clinical and prognostic effects of intravenous (i.v.) iron therapy in patients with systolic heart failure (HF) and iron deficiency (ID).

METHODS AND RESULTS

We performed an aggregate data meta-analysis (random effects model) of randomized controlled trials that evaluated the effects of i.v. iron therapy in iron-deficient patients with systolic HF. We searched electronic databases up to September 2014. We identified five trials which fulfilled the inclusion criteria (509 patients received i.v. iron therapy in comparison with 342 controls). Intravenous iron therapy has been shown to reduce the risk of the combined endpoint of all-cause death or cardiovascular hospitalization [odds ratio (OR) 0.44, 95% confidence interval (CI) 0.30-0.64, P < 0.0001], and the combined endpoint of cardiovascular death or hospitalization for worsening HF (OR 0.39, 95% CI 0.24-0.63, P = 0.0001). Intravenous iron therapy resulted in a reduction in NYHA class (data are reported as a mean net effect with 95% CIs for all continuous variables) (-0.54 class, 95% CI -0.87 to -0.21, P = 0.001); an increase in 6-min walking test distance (+31 m, 95% CI 18-43, P < 0.0001); and an improvement in quality of life [Kansas City Cardiomyopathy Questionnaire (KCCQ) score +5.5 points, 95% CI 2.8-8.3, P < 0.0001; European Quality of Life-5 Dimensions (EQ-5D) score +4.1 points, 95% CI 0.8-7.3, P = 0.01; Minnesota Living With Heart Failure Questionnaire (MLHFQ) score -19 points, 95% CI:-23 to -16, P < 0.0001; and Patient Global Assessment (PGA) +0.70 points, 95% CI 0.31-1.09, P = 0004].

CONCLUSION

The evidence indicates that i.v. iron therapy in iron-deficient patients with systolic HF improves outcomes, exercise capacity, and quality of life, and alleviates HF symptoms.

The influence of iron deficiency on the functioning of skeletal muscles: experimental evidence and clinical implications

Skeletal and respiratory myopathy not only constitutes an important pathophysiological feature of heart failure and chronic obstructive pulmonary disease, but also contributes to debilitating symptomatology and predicts worse outcomes in these patients. Accumulated evidence from laboratory experiments, animal models, and interventional studies in sports medicine suggests that undisturbed systemic iron homeostasis significantly contributes to the effective functioning of skeletal muscles. In this review, we discuss the role of iron status for the functioning of skeletal muscle tissue, and highlight iron deficiency as an emerging therapeutic target in chronic diseases accompanied by a marked muscle dysfunction.

Could the two-minute step test be an alternative to the six-minute walk test for patients with systolic heart failure?

BACKGROUND

The consequence of exercise intolerance for patients with heart failure is the difficulty climbing stairs. The two-minute step test is a test that reflects the activity of climbing stairs.

DESIGN

The aim of the study design is to evaluate the applicability of the two-minute step test in an assessment of exercise tolerance in patients with heart failure and the association between the six-minute walk test and the two-minute step test.

METHODS

Participants in this study were 168 men with systolic heart failure (New York Heart Association (NYHA) class I-IV). In the study we used the two-minute step test, the six-minute walk test, the cardiopulmonary exercise test and isometric dynamometer armchair.

RESULTS

Patients who performed more steps during the two-minute step test covered a longer distance during the six-minute walk test (r = 0.45). The quadriceps strength was correlated with the two-minute step test and the six-minute walk test (r = 0.61 and r = 0.48). The greater number of steps performed during the two-minute step test was associated with higher values of peak oxygen consumption (r = 0.33), ventilatory response to exercise slope (r = -0.17) and longer time of exercise during the cardiopulmonary exercise test (r = 0.34). Fatigue and leg fatigue were greater after the two-minute step test than the six-minute walk test whereas dyspnoea and blood pressure responses were similar.

CONCLUSION

The two-minute step test is well tolerated by patients with heart failure and may thus be considered as an alternative for the six-minute walk test.

Sleep-disordered breathing and cardiovascular disease

Sleep-disordered breathing (SDB) is a common comorbidity in a number of cardiovascular diseases, and mounting clinical evidence demonstrates that it has important implications in the long-term outcomes of patients with cardiovascular disease (CVD). While recognition among clinicians of the role of SDB in CVD is increasing, it too often remains neglected in the routine care of patients with CVD, and therefore remains widely undiagnosed and untreated. In this article, we provide an overview of SDB and its relationship to CVD, with the goal of helping cardiovascular clinicians better recognize and treat this important comorbidity in their patients. We will describe the two major types of SDB and discuss the pathophysiologic, diagnostic, and therapeutic considerations of SDB in patients with CVD.

Cardiac cachexia: hic et nunc: "hic et nunc" - here and now

Cardiac cachexia (CC) is the clinical entity at the end of chronic natural course of heart failure (HF). Despite the efforts, even the most recent definition of cardiac cachexia has been challenged, more precisely the addition of new criteria on top of obligatory weight loss. The pathophysiology of CC is complex and multifactorial. Better understanding of pathophysiological pathways in body wasting will contribute to establish potentially novel treatment strategies. The complex biochemical network related with CC and HF pathophysiology underlines that a single biomarker cannot reflect all of the features of the disease. Biomarkers that could pick-up the changes in body composition before they convey into clinical manifestations of CC would be of great importance. The development of preventive and therapeutic strategies against cachexia, sarcopenia and wasting disorders is perceived as an urgent need by healthcare professionals. The treatment of body wasting remains an unresolved challenge to this day. As CC is a multifactorial disorder, it is unlikely that any single agent will be completely effective in treating this condition. Among all investigated therapeutic strategies, aerobic exercise training in HF patients is the most proved to counteract skeletal muscle wasting and is recommended by treatment guidelines for HF.

The wasting continuum in heart failure: from sarcopenia to cachexia

Sarcopenia (muscle wasting) and cachexia share some pathophysiological aspects. Sarcopenia affects approximately 20 %, cachexia <10 % of ambulatory patients with heart failure (HF). Whilst sarcopenia means loss of skeletal muscle mass and strength that predominantly affects postural rather than non-postural muscles, cachexia means loss of muscle and fat tissue that leads to weight loss. The wasting continuum in HF implies that skeletal muscle is lost earlier than fat tissue and may lead from sarcopenia to cachexia. Both tissues require conservation, and therapies that stop the wasting process have tremendous therapeutic appeal. The present paper reviews the pathophysiology of muscle and fat wasting in HF and discusses potential treatments, including exercise training, appetite stimulants, essential amino acids, growth hormone, testosterone, electrical muscle stimulation, ghrelin and its analogues, ghrelin receptor agonists and myostatin antibodies.

Uric acid and xanthine oxidase in heart failure - Emerging data and therapeutic implications

The role of hyperuricaemia as cardiovascular risk factor has exhaustingly been debated for decades. While the association of elevated uric acid (UA) levels with increased mortality risk as convincingly been shown, the question whether UA is independently predictive of just a related effect within a more complex risk factor profile (including metabolic, inflammatory and haemodynamic risk factors) is still a matter of dispute. In heart failure the independent prognostic and functional impact of elevated UA has not only been shown but also the pathophysiologic mechanism(s) and the potential of targeted therapeutic interventions have been investigated in some detail. The emerging picture suggests the increased activity of the enzyme xanthine oxidase (XO) with corresponding increased production of free oxygen radical (ROS) as a main underlying principle with the resulting increase in UA levels being mostly a marker of this up-regulated pathway. While this concept will not diminish the value of UA as a prognostic marker, it provides the basis for a novel metabolic treatment option and the means to identify those patients most eligible for this tailored therapy. This review will summarize the recent evidence on XO as a novel and promising therapeutic target in heart failure.