Mechanisms by which exercise training benefits patients with heart failure. Nat Rev Cardiol. 2009;6:292-300. [PMID: 19352333 DOI: 10.1038/nrcardio.2009.8]

Non-Pharmacological Interventions in Patients With Heart Failure With Reduced Ejection Fraction: A Systematic Review and Network Meta-analysis

OBJECTIVE

To determine the effectiveness of non-pharmacologic interventions and the additional benefits of their combination in patients with heart failure with reduced ejection fraction (HFrEF).

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Clinical Trials Register from the date of database inception to April 22, 2023.

STUDY SELECTION

Randomized controlled trials involving non-pharmacologic interventions conducted in patients with HFrEF were included.

DATA EXTRACTION

Data were extracted by 2 independent reviewers based on a pre-tested data extraction form. The quality of evidence was assessed using the Cochrane Risk of Bias tool and the Grading of Recommendations Assessment, Development, and Evaluation method.

DATA SYNTHESIS

A total of 82 eligible studies (4574 participants) were included. We performed a random-effects model within a Bayesian framework to calculate weighted mean differences (WMDs) and 95% credibility intervals. High or moderate certainty evidence indicated that high-intensity aerobic interval training (HIAIT) was best on improving 6-minute walk distance (6MWD; 68.55 m [36.41, 100.47]) and left ventricular ejection fraction (6.28% [3.88, 8.77]), while high-intensity aerobic continuous training (HIACT) is best on improving peak oxygen consumption (Peak VO2; 3.48 mL/kg•min [2.84, 4.12]), quality of life (QOL; -17.26 [-29.99, -7.80]), resting heart rate (-8.20 bpm [-13.32, -3.05]), and N-terminal pro-B-type natriuretic peptide (-600.96 pg/mL [-902.93, -404.52]). Moderate certainty evidence supported the effectiveness of inspiratory muscle training to improve peak oxygen consumption and functional electrical stimulation to improve QOL. Moderate-intensity aerobic continuous training (MIACT) plus moderate-intensity resistance training (MIRT) had additional benefits in Peak VO2, 6MWD, and QOL. This review did not provide a comprehensive evaluation of adverse events.

CONCLUSIONS

Both HIAIT and HIACT are the most effective single non-pharmacologic interventions for HFrEF. MIACT plus MIRT had additional benefits in improving peak oxygen consumption, 6MWD, and QOL.

Exercise training decreases the load and changes the content of circulating SDS-resistant protein aggregates in patients with heart failure with reduced ejection fraction

BACKGROUND

Heart failure (HF) often disrupts the protein quality control (PQC) system leading to protein aggregate accumulation. Evidence from tissue biopsies showed that exercise restores PQC system in HF; however, little is known about its effects on plasma proteostasis.

AIM

To determine the effects of exercise training on the load and composition of plasma SDS-resistant protein aggregates (SRA) in patients with HF with reduced ejection fraction (HFrEF).

METHODS

Eighteen patients with HFrEF (age: 63.4 ± 6.5 years; LVEF: 33.4 ± 11.6%) participated in a 12-week combined (aerobic plus resistance) exercise program (60 min/session, twice per week). The load and content of circulating SRA were assessed using D2D SDS-PAGE and mass spectrometry. Cardiorespiratory fitness, quality of life, and circulating levels of high-sensitive C-reactive protein, N-terminal pro-B-type natriuretic peptide (NT-proBNP), haptoglobin and ficolin-3, were also evaluated at baseline and after the exercise program.

RESULTS

The exercise program decreased the plasma SRA load (% SRA/total protein: 38.0 ± 8.9 to 36.1 ± 9.7%, p = 0.018; % SRA/soluble fraction: 64.3 ± 27.1 to 59.8 ± 27.7%, p = 0.003). Plasma SRA of HFrEF patients comprised 31 proteins, with α-2-macroglobulin and haptoglobin as the most abundant ones. The exercise training significantly increased haptoglobin plasma levels (1.03 ± 0.40 to 1.11 ± 0.46, p = 0.031), while decreasing its abundance in SRA (1.83 ± 0.54 × 1011 to 1.51 ± 0.59 × 1011, p = 0.049). Cardiorespiratory fitness [16.4(5.9) to 19.0(5.2) ml/kg/min, p = 0.002], quality of life, and circulating NT-proBNP [720.0(850.0) to 587.0(847.3) pg/mL, p = 0.048] levels, also improved after the exercise program.

CONCLUSION

Exercise training reduced the plasma SRA load and enhanced PQC, potentially via haptoglobin-mediated action, while improving cardiorespiratory fitness and quality of life of patients with HFrEF.

The impacts of exercise interventions on inflammaging markers in overweight/obesity patients with heart failure: A systematic review and meta-analysis of randomized controlled trials

Objectives

The purpose of this meta-analysis was to investigate the association of aerobic, resistance and concurrent exercises vs. control group on inflammaging markers [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1-beta, IL-8, and high sensitivity C-reactive protein (hs-CRP)] in overweight or obesity patients with heart failure (HF).

Methods

The databases of Scopus, PubMed, Web of Science and Google Scholar were searched until August 31, 2022 for exercise interventions vs. control group on circulating inflammaging markers in patients with HF. Only randomized controlled trial (RCT) articles were included. Standardized mean difference (SMD) and 95% confidence intervals (95%CIs) were calculated (registration code = CRD42022347164).

Results

Forty-six full-text articles (57 intervention arms and 3693 participants) were included. A significant reduction was occurred in inflammaging markers of IL-6 [SMD-0.205(95% CI:-0.332 to -0.078),p = 0.002] and hs-CRP [SMD -0.379 (95% CI:-0.556 to -0.202), p = 0.001] with exercise training in patients with HF. Analysis of subgroup by age, body mass index (BMI), type, intensity, duration of exercise and mean left ventricular ejection fraction (LVEF) revealed that there was a significant reduction in TNF-α for middle-aged (p = 0.031), concurrent training (p = 0.033), high intensity (p = 0.005), and heart failure with reduced ejection fraction (HFrEF) (p = 0.007) compared to the control group. There was a significant reduction in IL-6 for middle-aged (p = 0.006), overweight (p = 0.001), aerobic exercise (p = 0.001), both high and moderate intensities (p = 0.037 and p = 0.034), short-term follow-up (p = 0.001), and heart failure with preserved ejection fraction (HFpEF) (p = 0.001) compared to the control group. There was a significant reduction in hs-CRP for middle-aged (p = 0.004), elderly-aged (p = 0.001), overweight (p = 0.001), aerobic exercise (p = 0.001), concurrent training (p = 0.031), both high and moderate intensities (p = 0.017 and p = 0.001), short-term (p = 0.011), long-term (p = 0.049), and very long-term (p = 0.016) follow-ups, HFrEF (p = 0.003) and heart failure with mildly reduced ejection fraction (HFmrEF) (p = 0.048) compared to the control group.

Conclusions

The results confirmed that aerobic exercise and concurrent training interventions were effective to improve inflammaging markers of TNF-α, IL-6, and hs-CRP. These exercise-related anti-inflammaging responses were observed across ages (middle-aged and elderly-aged), exercise intensities, duration of follow-ups, and mean LVEFs (HFrEF, HFmrEF and HFpEF) in overweight patients with HF.

The Role of Exercise-based Cardiac Rehabilitation in Heart Failure

Exercise-based cardiac rehabilitation (EBCR) is a treatment modality for patients with heart failure (HF) that has withstood the test of time. It has continued to show benefits even in the current era of pharmacotherapeutics for HF. Participation in a multidisciplinary comprehensive EBCR programme reduces mortality and morbidity, has a multitude of physiological benefits, and improves cardiovascular risk factor control and quality of life. Despite this, historical barriers to enrolment and uptake remain. Strategies to overcome these, as well as alternative delivery methods of EBCR in HF patients, are emerging and include telerehabilitation, focus on special groups and emphasis on behavioural change. This review provides oversight on the modalities of exercise training in HF as well as their benefits and gives an overview of barriers to the utilisation of EBCR along with future progress in the field.

Effects of Concurrent, Within-Session, Aerobic and Resistance Exercise Training on Functional Capacity and Muscle Performance in Elderly Male Patients with Chronic Heart Failure

BACKGROUND

The best format of exercise training (ET) in the setting of cardiac rehabilitation in patients with chronic heart failure (CHF) is still to be defined. Current guidelines recommend aerobic exercises, such as running and cycling, including some sessions per week of resistance exercise.

AIM

The aim of this study was to address the effectiveness of a concurrent exercise training program utilizing a circuit of sequential endurance and resistance exercises on functional capacity and muscular strength in patients with CHF.

METHODS

Ninety-five consecutive male patients (age 63.1 ± 6 years) with CHF (EF < 40%) in NYHA functional class II/III, were randomly assigned on 1:1 basis to a 12-week aerobic continuous training (AT) or concurrent CT), aerobic + resistance, training (CT), three times a week, with each session lasting 80 min. We used high quality, specifically designed ergometers, connected with each other and governed by a central console, and managed by a single physiotherapist. Before and after training all patients performed a symptoms-limited exercise test on a treadmill and a 6-min walking test (6MWT). Patients in the CT group also performed resistance exercises of upper and lower body.

RESULTS

The 6MWT and exercise duration at ergometric test increased significantly in both AT and CT groups, with the increase being greater in CT group (p < 0.001; ES = 0.13; p < 0.01; ES = 0.07). Muscular strength increased significantly in the CT group, particularly in the lower body muscular districts (p < 0.001). Quality of life improved in both groups, with a significantly greater improvement in the CT group (p < 0.05). No side effects leading to discontinuation of training were observed.

CONCLUSIONS

These findings indicate that concurrent, within-session training results in larger improvements in functional capacity, in addition to muscle performance, in patients with CHF, in comparison to single-mode aerobic training.

The effect of exercise training and physiotherapy on left and right heart function in heart failure with preserved ejection fraction: a systematic literature review

The impact of exercise training and physiotherapy on heart function and pulmonary circulation parameters in heart failure with preserved ejection fraction (HFpEF) patients is uncertain. Hence, we performed a systematic review of published trials studying physical training in HFpEF population, with a focus on exercise and physiotherapy effect on left ventricular (LV), right ventricular (RV) morphological, functional, and pulmonary circulation parameters. We searched Cochrane Library and MEDLINE/PubMed for trials that evaluated the effect of exercise training and/or physiotherapy in adult HFpEF patients (defined as LVEF ≥ 45%), including publications until March 2021. Our systematic review identified eighteen articles (n = 418 trained subjects, 4 to 52 weeks of training) and covered heterogeneous trials with various populations, designs, methodologies, and interventions. Five of twelve trials revealed a significant reduction of mitral E/e' ratio after the training (- 1.2 to - 4.9). Seven studies examined left atrial volume index; three of them showed its decrease (- 3.7 to - 8 ml/m²). Findings were inconsistent regarding improvement of cardiac output, E/A ratio, and E wave DecT and uncertain for RV function and pulmonary hypertension parameters. For now, no reliable evidence about rehabilitation effect on HFpEF cardiac mechanisms is available. There are some hypotheses generating findings on potential positive effects to parameters of LV filling pressure (E/e'), left atrium size, cardiac output, and RV function. This encourages a broader and more complex assessment of parameters reflecting cardiac function in future HFpEF exercise training studies.

Hyperbaric oxygenation applied before or after mild or hard stress: effects on the redox state in the muscle tissue

The mechanism is unclear for the reported protective effect of hyperbaric oxygen preconditioning against oxidative stress in tissues, and the distinct effects of hyperbaric oxygen applied after stress. The trained mice were divided into three groups: the control, hyperbaric oxygenation preconditioning, and hyperbaric oxygenation applied after mild (fasting) or hard (prolonged exercise) stress. After preconditioning, we observed a decrease in basal levels of nitric oxide, tetrahydrobiopterin, and catalase despite the drastic increase in inducible and endothelial nitric oxide synthases. Moreover, the basal levels of glutathione, related enzymes, and nitrosative stress only increased in the preconditioning group. The control and preconditioning groups showed a similar mild stress response of the endothelial and neuronal nitric oxide synthases. At the same time, the activity of all nitric oxide synthase, glutathione (GSH) in muscle, declined in the experimental groups but increased in control during hard stress. The results suggested that hyperbaric oxygen preconditioning provoked uncoupling of nitric oxide synthases and the elevated levels of GSH in muscle during this study, while hyperbaric oxygen applied after stress showed a lower level of GSH but higher recovery post-exercise levels in the majority of antioxidant enzymes. We discuss the possible mechanisms of the redox response and the role of the nitric oxide in this process.

Cognitive decline in heart failure: Biomolecular mechanisms and benefits of exercise

By definition, heart failure (HF) is a human pathological condition affecting the structure and function of all organs in the body, and the brain is not an exception to that. Failure of the heart to pump enough blood centrally and peripherally is at the foundation of HF patients' inability to attend even the most ordinary daily activities and progressive deterioration of their cognitive capacity. What is more, between heart and brain exists a bidirectional relationship that goes well beyond hemodynamics and concerns bioelectric and endocrine signaling. This increasingly consolidated evidence makes the scenario even more complex. Studies have mainly chased how HF impairs cognition without focusing much on preventive measures, notably cardio-cerebral health proxies. Here, we aim to provide a brief account of known and hypothetical factors that may explain how exercise can help obviate cognitive dysfunction associated with HF in its different forms. As we shall see, there is a stringent need for a deeper grasp of such mechanisms. Indeed, gaining this new knowledge will automatically shed new light on the inner workings of HF itself, thus resulting in more effective prevention and treatment of this escalating syndrome.

The Risk of Sudden Death Associated with Symptomatic and Asymptomatic Ventricular Pre-excitation in Athletes

Sudden death (SD) in athletes is a potential avoidable dramatic scenario. When done regularly, cardiological evaluation increases the chances of diagnosing ventricular pre-excitation. Consequently, the following question arises: what is the real incidence of SD risk in athletes with Wolff-Parkinson-White (WPW) syndrome/pattern? This study included 84 consecutive patients diagnosed with WPW and was designed as a retrospective analysis of data acquired between 2011 and 2021 to answer this question. The patients were evaluated using a 12-lead electrocardiogram (ECG), echocardiography, stress test, and electrophysiological study (EPS). The SD risk linked to WPW was defined as ≥ 1 of the following: the anterograde effective refractory period (AERP) of the accessory pathway (AP) ≤ 250 ms, atrial fibrillation (AF) with the shortest RR pre-excited interval ≤ 250 ms, syncope during AF or atrioventricular reentry tachycardia. The athletes with WPW pattern (n=25) or syndrome (n=59) at risk of SD were identified and treated with radiofrequency ablation (RFA). The mean age was 19.83 (10–29) years; 66.6% were men. Seventeen athletes (n=17; 20.23%) were found with SD risk: 15 (n=15; 17.85%) in the WPW syndrome group and 2 (n=2; 2.38%) in the WPW pattern group. During the EPS, n=4 developed syncope: 1 during antidromic tachycardia and 3 during pre-excited AF. RFA was curative in 96.42% of cases. The EPS is mandatory to identify athletes with short AERP APs linked to an increased risk of SD. RFA is the intervention that settles the patients into a risk-free area, allowing resumption of sports shortly afterward.

Aerobic Physical Exercise as a Non-medical Intervention for Brain Dysfunction: State of the Art and Beyond

Brain disorders, including stroke, Alzheimer's disease, depression, and chronic pain, are difficult to effectively treat. These major brain disorders have high incidence and mortality rates in the general population, and seriously affect not only the patient's quality of life, but also increases the burden of social medical care. Aerobic physical exercise is considered an effective adjuvant therapy for preventing and treating major brain disorders. Although the underlying regulatory mechanisms are still unknown, systemic processes may be involved. Here, this review aimed to reveal that aerobic physical exercise improved depression and several brain functions, including cognitive functions, and provided chronic pain relief. We concluded that aerobic physical exercise helps to maintain the regulatory mechanisms of brain homeostasis through anti-inflammatory mechanisms and enhanced synaptic plasticity and inhibition of hippocampal atrophy and neuronal apoptosis. In addition, we also discussed the cross-system mechanisms of aerobic exercise in regulating imbalances in brain function, such as the “bone-brain axis.” Furthermore, our findings provide a scientific basis for the clinical application of aerobic physical exercise in the fight against brain disorders.

Exercise-Generated β-Aminoisobutyric Acid (BAIBA) Reduces Cardiomyocyte Metabolic Stress and Apoptosis Caused by Mitochondrial Dysfunction Through the miR-208b/AMPK Pathway

Objective

To explore the cardioprotective effects of exercise-derived β-aminoisobutyric (BAIBA) on cardiomyocyte apoptosis and energy metabolism in a rat model of heart failure (HF).

Methods

In male Sprague-Dawley rats (8-week-old), myocardial infarction (MI) was used to induce HF by ligating the left anterior descending branch of the coronary artery. In the Sham group, the coronary artery was threaded but not ligated. After HF development, Sham and HF rats were exercised 60 min daily, 5 days/week on a treadmill for 8 weeks (50–60% maximal intensity) and exercise-induced cardiac remodeling after MI were assessed using echocardiography, hematoxylin and eosin (H&E), Masson's Trichrome, and TUNEL staining for the detection of apoptosis-associated factors in cardiac tissue. High-throughput sequencing and mass spectrometry were used to measure BAIBA production and to explore its cardioprotective effects and molecular actions. To further characterize the cardioprotective effects of BAIBA, an in vitro model of apoptosis was generated by applying H₂O₂ to H9C2 cells to induce mitochondrial dysfunction. In addition, cells were transfected with either a miR-208b analog or a miR-208b inhibitor. Apoptosis-related proteins were detected by Western Blotting (WB). ATP production was also assessed by luminometry. After administration of BAIBA and Compound C, the expression of proteins related to apoptosis, mitochondrial function, lipid uptake, and β-oxidative were determined. Changes in the levels of reactive oxygen species (ROS) were assessed by fluorescence microscopy. In addition, alterations in membrane potential (δψm) were obtained by confocal microscopy.

Results

Rats with HF after MI are accompanied by mitochondrial dysfunction, metabolic stress and apoptosis. Reduced expression of apoptosis-related proteins was observed, together with increased ATP production and reduced mitochondrial dysfunction in the exercised compared with the Sham (non-exercised) HF group. Importantly, exercise increased the production of BAIBA, irrespective of the presence of HF. To assess whether BAIBA had similar effects to exercise in ameliorating HF-induced adverse cardiac remodeling, rats were treated with 75 mg/kg/ day of BAIBA and we found BAIBA had a similar cardioprotective effect. Transcriptomic analyses found that the expression of miR-208b was increased after BAIBA administration, and subsequent transfection with an miR-208b analog ameliorated both the expression of apoptosis-related proteins and energy metabolism in H₂O₂-treated H9C2 cells. In combining transcriptomic with metabolomic analyses, we identified AMPK as a downstream target for BAIBA in attenuating metabolic stress in HF. Further cell experiments confirmed that BAIBA increased AMPK phosphorylation and had a cardioprotective effect on downstream fatty acid uptake, oxidative efficiency, and mitochondrial function, which was prevented by the AMPK inhibitor Compound C.

Conclusion

Exercise-generated BAIBA can reduce cardiomyocyte metabolic stress and apoptosis induced by mitochondrial dysfunction through the miR-208b/AMPK pathway.

Passive leg cycling increases activity of the cardiorespiratory system in people with tetraplegia

Individuals with cervical spinal cord injury (SCI) are at an increased risk for cardiovascular disease. Exercise is well-established for preventing cardiovascular disease, however, there are limited straightforward and safe exercise approaches for increasing the activity of the cardiorespiratory system after cervical SCI. The objective of this study was to investigate the cardiorespiratory response to passive leg cycling in people with cervical SCI. Beat-by-beat blood pressure, heart rate, and cerebral blood flow were measured before and throughout 10 minutes of cycling in 11 people with SCI. Femoral artery flow-mediated dilation was also assessed before and immediately after passive cycling. Safety was monitored throughout all study visits. Passive cycling elevated systolic blood pressure (5±2 mmHg), mean arterial pressure (5±3 mmHg), stroke volume (2.4±0.8 mL), heart rate (2±1 beats/min) and cardiac output (0.3±0.07 L/min; all p<0.05). Minute ventilation (0.67±0.23 L/min), tidal volume (70±30 mL) and end-tidal PO2 (2.6±1.23 mmHg) also increased (all p<0.05). Endothelial function was improved immediately after exercise (1.62±0.13%, p<0.01). Passive cycling resulted in one incidence of autonomic dysreflexia. Therefore, passive leg cycling increased the activity of the cardiorespiratory system, improved endothelial function, indicating it may be a beneficial exercise intervention for the cardiovascular and respiratory systems in people with cervical SCI. Novelty: ● Passive leg cycling increases the activity of the cardiorespiratory system and improves markers of cardiovascular health in cervical SCI. ● Passive leg cycling exercise is an effective, low-cost, practical, alternative exercise modality for people with cervical SCI.

Cardiac Rehabilitation in a Patient With Severe Heart Failure and Ventricular Septal Defect Secondary to Acute Myocardial Infarction

The treatment of choice for patients with advanced heart failure (HF) and with limiting symptoms with evidence of a poor prognosis despite optimal conventional treatment is a heart transplant. However, there is little literature dealing with the effects of cardiovascular prehabilitation with an important change in physical capacity, which can influence the admission on the waiting list for a heart transplant. We presented one young male, smoker, with no prior history of cardiovascular disease, severe ventricular dysfunction, interventricular defect, and HF. It was decided to implant a cardioverter-defibrillator as primary prevention of sudden death and start the pre-cardiac transplant evaluation and subsequent inclusion in the waiting list on an elective basis. While waiting for the transplant, cardiopulmonary rehabilitation (CPR) was indicated. After 15 months of CPR, the patient improved his left ventricular ejection fraction (LVEF; 20% to 40%), systolic pulmonary artery pressure (55 to 40 mmHg), and peak oxygen uptake (23.9 to 29.1 ml/kg/min). In this patient, a program of CPR improved cardiac function and physical capacity, allowing him to be removed from the national waiting list for a heart transplant.

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.

Unveiling the role of exercise training in targeting the inflammatory paradigm of heart failure with preserved ejection fraction: a narrative review

Heart failure with preserved ejection fraction (HFpEF) is currently lacking an effective pharmacological treatment with impact on major outcomes such as hospitalization and mortality. Exercise training (EXT) is recognized as an important nonpharmacological tool, capable of improving exercise capacity and quality of life, and has even been associated with a reduction in hospitalization and cardiovascular mortality risk. However, this positive impact largely lacks a physiological explanation. The aim of this narrative review was to provide an overview of the available data supporting the hypothesis that the beneficial role of EXT in HFpEF might be due to its effects on targeting the inflammatory paradigm described for this disease. A comprehensive literature search was conducted using the PubMed-NCBI database. We reviewed the effects of EXT throughout each step of the pathophysiological pathway leading to HFpEF and found clinical and/or preclinical evidence supporting the reduction of systemic inflammation, endothelial dysfunction, microvascular rarefaction, and myocardial stiffness. We also highlighted some gaps in the knowledge or topics that deserve further clarification in future studies. In conclusion, despite the scarcity of clinical studies in this population, there is compelling evidence suggesting that EXT modulates crucial aspects of the inflammatory pathway described for HFpEF and future investigation on cellular and molecular mechanisms are encouraged.

Exercise-based rehabilitation strategies in heart transplant recipients: Focus on high-intensity interval training

Despite progressive improvement in medical therapy and standard care, the exercise capacity of heart transplant recipients is reduced compared with age-matched healthy individuals. Exercise-based rehabilitation programs have been shown to improve the exercise capacity of transplant patients through a multifactorial effect. In this context, high-intensity interval exercise is a growing field of research, with current evidence suggesting a major benefit in heart transplant recipients compared with a conventional training protocol. Therefore, this study aimed to provide an overview of the mechanisms involved in the reduced exercise capacity of heart transplant patients and a review of current rehabilitation strategies with a special focus on the mechanisms and clinical effects of high-intensity interval training exercise.

Epigenetic-sensitive liquid biomarkers and personalised therapy in advanced heart failure: a focus on cell-free DNA and microRNAs

Dilated cardiomyopathy (DCM) represents a common genetic cause of mechanical and/or electrical dysfunction leading to heart failure (HF) onset for which truncating variants in titin (TTN) gene result in the most frequent mutations. Moreover, myocyte and endothelial cell apoptosis is a key endophenotype underlying cardiac remodelling. Therefore, a deeper knowledge about molecular networks leading to acute injury and apoptosis may reveal novel circulating biomarkers useful to better discriminate HF phenotypes, patients at risk of heart transplant as well as graft reject in order to improve personalised therapy. Remarkably, increased plasma levels of cell-free DNA (cfDNA) may reflect the extent of cellular damage, whereas circulating mitochondrial DNA (mtDNA) may be a promising biomarker of poor prognosis in patients with HF. Furthermore, some panels of circulating miRNAs may improve the stratification of natural history of disease. For example, a combination of miR-558, miR-122* and miR-520d-5p, as well as miR-125a-5p, miR-550a-5p, miR-638 and miR-190a, may aid to discriminate different phenotypes of HF ranging from preserved to reduced ejection fraction. We give update on the most relevant genetic determinants involved in DCM and discuss the putative role of non-invasive biomarkers to overcome current limitations of the reductionist approach in HF management.

High-intensity interval training recuperates capacity of endogenous thrombin generation in heart failure patients with reduced ejection fraction

OBJECTIVE

Consumptive coagulopathy is associated with increased mortality in patients with heart failure (HF). Physical activity influences the risk of major vascular thrombotic events. This study investigates how high-intensity interval training (HIIT) affects the capacity of endogenous thrombin generation (TG) by modulating circulatory procoagulant microparticles (MPs) in HF patients.

METHODS

Thirty-eight HF patients with reduced ejection fraction (HFrEF) and 38 age- and gender-matched normal counterparts (NC) were recruited into this study. The HFrEF group performed HIIT (3-min intervals at 40% and 80%VO_2peak) on a bicycle ergometer for 30 min/day, 3 days/week for 12 weeks, whereas the NC group did not receive any form of intervention. Plasma TG kinetics, procoagulant MPs, coagulation-related factors, and oxidative stress/proinflammatory status were analyzed.

RESULTS

The HFrEF group exhibited (i) less endogenous thrombin potential (ETP) and TG rate, (ii) lower concentration/activity of tissue factor (TF) and counts of TF-rich MPs derived from blood cells, and (iii) higher vascular endothelial shedding and plasma myeloperoxidase and interleukin-6 concentrations, compared to the NC group did. However, HIIT elevated TG rate and TF concentration/activity in plasma, as well as, TF-rich MP counts derived from blood cells in patients with HFrEF. Moreover, the exercise regimen also decreased vascular endothelial shedding and plasma myeloperoxidase and interleukin-6 concentrations in HFrEF patients.

CONCLUSION

HFrEF reduces the capacity of endogenous TG in plasma, which is associated with decreased (or consumed) circulatory procoagulant MP levels. However, HIIT alleviates HFrEF-declined endogenous TG capacity and vascular endothelial damage through recuperating TF-related coagulation activity and suppressing oxidative stress/proinflammatory status.

Physical activity for patients with heart failure: Position paper from the heart failure (GICC) and cardiac rehabilitation (GERS-P) Working Groups of the French Society of Cardiology

Physical activity is important in heart failure to improve functional capacity, quality of life and prognosis, and is a class IA recommendation in the European Society of Cardiology guidelines (Ponikowski et al., 2016). The benefits of exercise training are widely recognized. Cardiac rehabilitation centres offer tailored exercise training to patients with heart failure, as part of specialized multidisciplinary care, alongside pharmacological treatment optimization and patient education. After cardiac rehabilitation, maintenance of regular physical activity long term is essential, as the benefits of exercise training vanish within a few weeks. Unfortunately, only 10% of patients benefit from a cardiac rehabilitation programme after hospitalization for acute heart failure, and the majority of patients do not pursue long-term physical activity. In this paper, two Working Groups of the French Society of Cardiology (the heart failure group [Groupe Insuffisance Cardiaque et Cardiomyopathies; GICC] and the cardiac rehabilitation group [Groupe Exercice Réadaptation Sport et Prévention; GERS-P]) discuss the obstacles to broader access to cardiac rehabilitation centres, and propose ways to improve the diffusion of cardiac rehabilitation programmes and encourage long-term adherence to physical activity.

Progression of micturition dysfunction associated with the development of heart failure in rats: Model of overactive bladder

Heart failure (HF) has a strong association with the development of lower urinary tract symptoms, especially overactive bladder (OAB); although this condition remains poorly investigated. In this study, we assess the aortocaval fistula (ACF) model as a novel experimental model of micturition dysfunction, associated with HF, focused on the molecular and functional studies to evaluate the autonomic nervous system and urinary bladder remodeling. Male rats were submitted to ACF for HF induction. Echocardiography, cystometric, histomorphometry and molecular analysis, as well as concentration-response curves to carbachol and ATP and frequency-response curves to electrical field stimulation (EFS) were evaluated in Sham and HF (4- and 12-weeksendpoint) groups. Compared to SHAM, HF groups exhibited progressive increases in the left ventricle (LV) mass and fractional shortening which indicates cardiac dysfunction, although HF was characterized only after 12 weeks by the reduced ejection fraction. For micturition function, HF groups presented increased non-voiding contractions (NVC) and decreased bladder capacity; however, when comparing HF groups, these urinary parameters were significantly impaired over the weeks (12-weeks). The contractile responses induced by CCh, ATP and EFS were greater in detrusor muscle (DSM) from HF rats. mRNA expression for muscarinic receptors (M2 and M3) was higher in DSM only after 12 weeks of ACF, in addition to MMP9 and TGF-beta. Histomorphometric revealed increased urothelium thickness in both HF groups, whereas DSM thickness occurred only after 12 weeks. Thus, the ACF model induced cardiac dyfunction with progressive micturition dysfunction over the weeks, characterized by increased DSM contractile mechanisms as well as extracellular matrix remodeling in the urinary bladder, representing a useful tool to evaluate the OAB associated with HF.

Effects of Water-Based Aerobic Interval Training in Patients With COPD: A RANDOMIZED CONTROLLED TRIAL

PURPOSE

Chronic obstructive pulmonary disease promotes systemic repercussions, which can be minimized with physical exercise. This study investigated the effects of a water-based aerobic interval training program on the autonomic modulation of heart rate (HR), quality of life (QoL), and functional capacity (FC) of patients with chronic obstructive pulmonary disease.

METHODS

Nineteen patients with chronic obstructive pulmonary disease were enrolled in this randomized clinical trial and allocated to either the usual care group (n = 9) or training group (n = 10). Before and after 24 sessions of water-based physical training, the patients underwent evaluation of autonomic modulation of HR by analyzing the HR variability, QoL using the St George's Respiratory Questionnaire, and FC using 6-min walk test distance.

RESULTS

The results showed significant improvement when comparing the variables of HR variability, QoL, and FC in the training group in the pre- and post-training conditions (P < .05). In the usual care group, there was no significant difference for any of the variables. Negative correlations were found between HR variability and QoL (r =-0. 55; P = .01) and 6-min walk test distance and QoL (r =-0.49; P = .02).

CONCLUSION

Water-based physical training promoted beneficial adaptations in the autonomic modulation of HR, QoL, and FC of patients with chronic obstructive pulmonary disease.

BDNF contributes to the skeletal muscle anti-atrophic effect of exercise training through AMPK-PGC1α signaling in heart failure mice

INTRODUCTION

Exercise training is a coadjuvant therapy in preventive cardiology, and it delays cardiac dysfunction and exercise intolerance in heart failure (HF). However, the mechanisms underlying muscle function improvement and cardioprotection are poorly understood. In this study, we tested whether exercise training would counteract skeletal muscle atrophy via activation of the BDNF pathway in myocardial infarction (MI)-induced HF mice.

MATERIAL AND METHODS

A cohort of male Sham-operated and MI mice were assigned into 8-week moderate exercise training, and untrained counterparters were used as control. Exercise capacity, plasma norepinephrine (NE) level, heart rate (HR), fractional shortening (FS) and ejection fraction (EF) were measured. The protein expression of BDNF, p-TrkB, p-AMPK and PGC1α were analyzed by Western blot.

RESULTS

Compared with the Sham-operated mice, MI mice displayed reduced total distance run and elevated plasma NE level (both p < 0.05). Exercise training significantly improved distance run and plasma NE levels in HF mice (both p < 0.05). Significantly increased HR, decreased FS and EF were observed in the MI group as compared to the Sham-operated group, and exercise training prevent the hemodynamic status and systolic dysfunction in MI mice (all p < 0.05). The expression of BDNF, p-TrkB, p-AMPK and PGC1α were significantly decreased in the skeletal muscle from MI compared to Sham-operated mice, which were significantly increased by exercise training (all p < 0.05). In addition, BDNF siRNA markedly decreased the protein level of p-AMPK and PGC1α in C2C12 myoblasts.

CONCLUSIONS

Taken together, our data provide evidence for exercise training may counteract HF-induced muscle atrophy through induced activation of BDNF pathway.

Exercise during transition from compensated left ventricular hypertrophy to heart failure in aortic stenosis rats

We evaluated the influence of aerobic exercise on cardiac remodelling during the transition from compensated left ventricular (LV) hypertrophy to clinical heart failure in aortic stenosis (AS) rats. Eighteen weeks after AS induction, rats were assigned into sedentary (AS) and exercised (AS-Ex) groups. Results were compared to Sham rats. Exercise was performed on treadmill for 8 weeks. Exercise improved functional capacity. Echocardiogram showed no differences between AS-Ex and AS groups. After exercise, fractional shortening and ejection fraction were lower in AS-Ex than Sham. Myocyte diameter and interstitial collagen fraction were higher in AS and AS-Ex than Sham; however, myocyte diameter was higher in AS-Ex than AS. Myocardial oxidative stress, evaluated by lipid hydroperoxide concentration, was higher in AS than Sham and was normalized by exercise. Gene expression of the NADPH oxidase subunits NOX2 and NOX4, which participate in ROS generation, did not differ between groups. Activity of the antioxidant enzyme superoxide dismutase was lower in AS and AS-Ex than Sham and glutathione peroxidase was lower in AS-Ex than Sham. Total and reduced myocardial glutathione, which is involved in cellular defence against oxidative stress, was lower in AS than Sham and total glutathione was higher in AS-Ex than AS. The MAPK JNK was higher in AS-Ex than Sham and AS groups. Phosphorylated P38 was lower in AS-Ex than AS. Despite improving functional capacity, aerobic exercise does not change LV function in AS rats. Exercise restores myocardial glutathione, reduces oxidative stress, impairs JNK signalling and further induces myocyte hypertrophy.

Management of advanced heart failure: a review

INTRODUCTION

Heart failure (HF) has become a global pandemic. Despite recent developments in both medical and device treatments, HF incidences continues to increase. The current definition of HF restricts itself to stages at which clinical symptoms are apparent. In advanced heart failure (AdHF), it is universally accepted that all patients are refractory to traditional therapies. As the number of HF patients increase, so does the need for additional treatments, with an increased proportion of patients requiring advanced therapies. Areas covered: This review discusses extensive evidence for the effect of medical treatment on HF, although the data on the effect on AdHF is scare. Authors review the relevant literature for treating AdHF patients. Furthermore, mechanical circulatory devices (MCD) have emerged as an alternative to heart transplantation and have been shown to enhance quality of life and reduce mortality therefore authors also review the current literature on the different MCD and technologies. Expert commentary: More patients will need advanced therapies, as the access to heart transplantation is limited by the number of available donors. AdHF patients should be identified timely since the window of opportunities for advanced therapy is narrow as their morbidity is progressive and survival is often short.

Protective effect of physical activity on mortality in older adults with advanced chronic heart failure: A prospective observational study

Objectives

The objective of this study was to evaluate the effect on mortality of self-reported physical activity evaluated by the physical activity scale for the elderly (PASE) in elderly patients with advanced heart failure enrolled in a cardiac rehabilitation unit after heart failure decompensation (NYHA class IIIB).

Methods

The study prospectively enrolled 314 elderly patients (≥65 years) with heart failure in NYHA class IIIB (symptomatic with a recent history of dyspnoea at rest) consecutively admitted to cardiac rehabilitation between January 2010 and July 2011. Comprehensive geriatric assessment was performed. Physical activity was evaluated by PASE and stratified in tertiles (0–15, 16–75 and >75). Mortality was collected from September to October 2015 in 300 patients.

Results

The mean age was 74.5 ± 6.1 (range 65–89); 74.7% were men, 132 patients (44.0%) died during the follow-up (44.1 ± 20.7 months). Univariate analysis shows that physical activity level conducted before heart failure decompensation was inversely related to mortality (from 76.0% to 8.2%, P = 0.000). Multivariate analysis confirms that the PASE score predicts mortality independently of several demographic and clinical variables (hazard rate 0.987, 95% confidence interval (CI) 0.980–0.994, P = 0.000). Notably, when considering PASE 0–15 versus 16–75 score and PASE 0–15 versus > 75 score, the hazard rate is 4.06 (95% CI 1.67–9.84, P < 0.001) and 7.25 (95% CI 2.7–19.5, P < 0.001), respectively.

Conclusions

Physical activity level evaluated by the PASE score is inversely related to mortality in elderly patients with advanced heart failure confirming the reduction of mortality exerted by moderate physical activity in such patients.

Adenosine 5'-Triphosphate Metabolism in Red Blood Cells as a Potential Biomarker for Post-Exercise Hypotension and a Drug Target for Cardiovascular Protection

The importance of adenosine and ATP in regulating many biological functions has long been recognized, especially for their effects on the cardiovascular system, which may be used for management of hypertension and cardiometabolic diseases. In response to ischemia and cardiovascular injury, ATP is broken down to release adenosine. The effect of adenosine is very short lived because it is rapidly taken up by erythrocytes (RBCs), myocardial and endothelial cells, and also rapidly catabolized to oxypurine metabolites. Intracellular adenosine is phosphorylated back to adenine nucleotides via a salvage pathway. Extracellular and intracellular ATP is broken down rapidly to ADP and AMP, and finally to adenosine by 5′-nucleotidase. These metabolic events are known to occur in the myocardium, endothelium as well as in RBCs. Exercise has been shown to increase metabolism of ATP in RBCs, which may be an important mechanism for post-exercise hypotension and cardiovascular protection. The post-exercise effect was greater in hypertensive than in normotensive rats. The review summarizes current evidence in support of ATP metabolism in the RBC as a potential surrogate biomarker for cardiovascular protection and toxicities. It also discusses the opportunities, challenges, and obstacles of exploiting ATP metabolism in RBCs as a target for drug development and precision medicine.

Chronic interval exercise training prevents BKCa channel-mediated coronary vascular dysfunction in aortic-banded miniswine

Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Thus, the purpose of this study was to determine the therapeutic efficacy of chronic interval exercise training (IT) on large-conductance Ca²⁺-activated K⁺ (BK_Ca) channel-mediated coronary vascular function in heart failure. We hypothesized that chronic interval exercise training would attenuate pressure overload-induced impairments to coronary BK_Ca channel-mediated function. A translational large-animal model with cardiac features of HFpEF was used to test this hypothesis. Specifically, male Yucatan miniswine were divided into three groups ( n = 7/group): control (CON), aortic banded (AB)-heart failure (HF), and AB-interval trained (HF-IT). Coronary blood flow, vascular conductance, and vasodilatory capacity were measured after administration of the BK_Ca channel agonist NS-1619 both in vivo and in vitro in the left anterior descending coronary artery and isolated coronary arterioles, respectively. Skeletal muscle citrate synthase activity was decreased and left ventricular brain natriuretic peptide levels increased in HF vs. CON and HF-IT animals. A parallel decrease in NS-1619-dependent coronary vasodilatory reserve in vivo and isolated coronary arteriole vasodilatory responsiveness in vitro were observed in HF animals compared with CON, which was prevented in the HF-IT group. Although exercise training prevented BK_Ca channel-mediated coronary vascular dysfunction, it did not change BK_Ca channel α-subunit mRNA, protein, or cellular location (i.e., membrane vs. cytoplasm). In conclusion, these results demonstrate the viability of chronic interval exercise training as a therapy for central and peripheral adaptations of experimental heart failure, including BK_Ca channel-mediated coronary vascular dysfunction. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show that chronic interval exercise training can prevent BK_Ca channel-mediated coronary vascular dysfunction in a translational swine model of chronic pressure overload-induced heart failure with relevance to human HFpEF.

Importance of physical capacity and the effects of exercise in heart transplant recipients

One of the most important prognostic factors in heart failure patients is physical capacity. Patients with very poor physical performance and otherwise eligible, may be listed as candidates for heart transplantation (HTx). After such surgery, life-long immunosuppression therapy is needed to prevent rejection of the new heart. The dark side of immunosuppression is the increased risk of infections, kidney failure, cancer and advanced atherosclerosis (cardiac allograft vasculopathy), with the two latter conditions as the main causes of later mortality. In a worldwide perspective, 50% of the HTx patients survive past 10 years. Poor aerobic capacity prior to graft deterioration is not only limited to the failing heart, but also caused by peripheral factors, such as limited function in the skeletal muscles and in the blood vessels walls. Exercise rehabilitation after HTx is of major importance in order to improve physical capacity and prognosis. Effects of high-intensity interval training (HIT) in HTx recipients is a growing field of research attracting worldwide focus and interest. Accumulating evidence has shown that HIT is safe and efficient in maintenance HTx recipients; with superior effects on physical capacity compared to conventional moderate exercise. This article generates further evidence to the field by summarizing results from a decade of research performed at our center supported by a broad, but not strict formal, literature review. In short, this article demonstrates a strong association between physical capacity measured after HTx and long-term survival. It describes the possible “HIT-effect” with increased levels of inflammatory mediators of angiogenesis. It also describes long-term effects of HIT; showing a positive effect in development of anxiety symptoms despite that the improved physical capacity was not sustained, due to downregulation of exercise and intensity. Finally, our results are linked to the ongoing HITTS study, which investigates safety and efficiency of HIT in de novo HTx recipients. Together with previous results, this study may have the potential to change existing guidelines and contribute to a better prognosis for the HTx population as a whole.

Chronic low-intensity exercise attenuates cardiomyocyte contractile dysfunction and impaired adrenergic responsiveness in aortic-banded mini-swine

Exercise improves clinical outcomes in patients diagnosed with heart failure with reduced ejection fraction (HFrEF), in part via beneficial effects on cardiomyocyte Ca²⁺ cycling during excitation-contraction coupling (ECC). However, limited data exist regarding the effects of exercise training on cardiomyocyte function in patients diagnosed with heart failure with preserved ejection fraction (HFpEF). The purpose of this study was to investigate cardiomyocyte Ca²⁺ handling and contractile function following chronic low-intensity exercise training in aortic-banded miniature swine and test the hypothesis that low-intensity exercise improves cardiomyocyte function in a large animal model of pressure overload. Animals were divided into control (CON), aortic-banded sedentary (AB), and aortic-banded low-intensity trained (AB-LIT) groups. Left ventricular cardiomyocytes were electrically stimulated (0.5 Hz) to assess Ca²⁺ homeostasis (fura-2-AM) and unloaded shortening during ECC under conditions of baseline pacing and pacing with adrenergic stimulation using dobutamine (1 μM). Cardiomyocytes in AB animals exhibited depressed Ca²⁺ transient amplitude and cardiomyocyte shortening vs. CON under both conditions. Exercise training attenuated AB-induced decreases in cardiomyocyte Ca²⁺ transient amplitude but did not prevent impaired shortening vs. CON. With dobutamine, AB-LIT exhibited both Ca²⁺ transient and shortening amplitude similar to CON. Adrenergic sensitivity, assessed as the time to maximum inotropic response following dobutamine treatment, was depressed in the AB group but normal in AB-LIT animals. Taken together, our data suggest exercise training is beneficial for cardiomyocyte function via the effects on Ca²⁺ homeostasis and adrenergic sensitivity in a large animal model of pressure overload-induced heart failure. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show chronic low-intensity exercise training can prevent cardiomyocyte dysfunction and impaired adrenergic responsiveness in a translational large animal model of chronic pressure overload-induced heart failure with relevance to human HFpEF.

Additional value of anaerobic threshold in a general mortality prediction model in a urban patient cohort with Chagas cardiomyopathy

BACKGROUND

Anaerobic threshold (AT) is recognized as objective and direct measurement that reflects variations in metabolism of skeletal muscles during exercise. Its prognostic value in heart diseases of non-chagasic etiology is well established. However, the assessment of risk of death in Chagas heart disease is relatively well established by Rassi score. But, the added value that AT can bring to Rassi score has not been studied yet.

OBJECTIVES

To assess whether AT presents additional effect to Rassi score in patients with chronic Chagas' heart disease.

METHODS

Prospective research of dynamic cohort by review of 150 medical records of patients. Were selected for cohort 45 medical records of patients who underwent cardiopulmonary exercise testing between 1996-1997 and followed until September 2015. Data analysis to detect association between studied variables can be seen using a logistic regression model. The suitability of the models was verified using ROC curves and the coefficient of determination R².

RESULTS

8 patients (17.78%) died by September 2015, with 7 of them (87.5%) from cardiovascular causes, of which 4 (57.14%) were considered on high risk by Rassi score. With Rassi score as independent variable, and death being the outcome, we obtained an area under the curve (AUC)=0.711, with R²=0.214. Instituting AT as independent variable, we found AUC=0.706, with R²=0.078. When we define Rassi score and AT as independent variables, it was obtained AUC=0.800 and R²=0.263.

CONCLUSION

when AT is included in logistic regression, it increases by 5% the explanation (R²) to the death estimation.

Immediate response in markers of inflammation and angiogenesis during exercise: a randomised cross-over study in heart transplant recipients

Background

The present study explored and compared the immediate responses in markers of inflammation and angiogenesis in maintenance heart transplant (HTx) recipients before, during and after sessions of high-intensity interval training (HIT) versus moderate-intensity continuous training (MICT). The study aimed to explain some of the trigger mechanisms behind HIT in HTx recipients.

Methods

This cross-over study included 14 HTx patients (mean±SD age: 53±13 years; time since HTx, 3±2 years). All participants underwent baseline blood samples and a cardiopulmonary exercise test during their first visit. The next two visits included one HIT session and one MICT session, in randomised order. Blood samples were taken during and after each exercise session. Myokines and inflammatory markers related to vascular inflammation, blood-platelet activation and modulation of angiogenesis were analysed.

Results

The main findings in this study were (1) exercise, regardless of intensity, induced a significant immediate response in several vascular, angiogenetic and in particular platelet-derived inflammatory mediators in HTx recipients. (2) HIT showed trends to induce an increased response in von Willebrand factor, vascular endothelial growth factor-1 and angiopoetin-2, and a decreased response in growth differentiation factor-15, compared with MICT.

Conclusions

This pattern and in particular the trend towards an increased angiogenetic mediator response could contribute to the beneficial effects of HIT in HTx recipients.

Trial registration number

NCT02602834.

Moderate Exercise Has Limited but Distinguishable Effects on the Mouse Microbiome

The gut microbiome is known to have a complex yet vital relationship with host health. While both exercise and the gut microbiome have been shown to impact human health independently, the direct effects of moderate exercise on the intestinal microbiota remain unclear. In this study, we compared gut microbial diversity and changes in inflammatory markers associated with exercise over an 8-week period in mice that performed either voluntary exercise (VE) (n = 10) or moderate forced exercise (FE) (n = 11) and mice that did not perform any exercise (n = 21). VE mice, but not FE mice, had increased food intake and lean body mass compared to sedentary mice. The levels of inflammatory markers associated with exercise were similar for mice in all three groups. Traditional microbial profiles comparing operational taxonomic units (OTUs) in samples (P > 0.1) and multivariate analysis of beta diversity via Adonis testing (P > 0.1) did not identify significantly altered taxonomic profiles in the voluntary or forced exercise group compared to the sedentary controls. However, a random forests machine learning model, which takes into account the relationships between bacteria in a community, classified voluntary exercisers and nonexercisers with 97% accuracy at 8 weeks. The top bacteria used by the model allowed us to identify known taxa (Bacteroides, S24-7, and Lactobacillus) and novel taxa (Rikenellaceae and Lachnospiraceae) associated with exercise. Although aerobic exercise in mice did not result in significant changes of abundance in gut microbes or in host inflammatory response, more sophisticated computational methods could identify some microbial shifts. More study is needed on the effects of various exercise intensities and their impact on the gut microbiome. IMPORTANCE The bacteria that live in our gut have a complex yet vital relationship with our health. Environmental factors that influence the gut microbiome are of great interest, as recent research demonstrates that these microbes, mostly bacteria, are important for normal host physiology. Diseases such as obesity, diabetes, inflammatory bowel disease, and colon cancer have also been linked to shifts in the microbiome. Exercise is known to have beneficial effects on these diseases; however, much less is known about its direct impact on the gut microbiome. Our results illustrate that exercise has a moderate but measurable effect on gut microbial communities in mice. These methods can be used to provide important insight into other factors affecting the microbiome and our health.

High-intensity Interval training enhances mobilization/functionality of endothelial progenitor cells and depressed shedding of vascular endothelial cells undergoing hypoxia

PURPOSE

Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte-derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate-intensity continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition.

METHODS

Sixty healthy sedentary males were randomized to engage in either HIT (3-min intervals at 40 and 80 % VO_2max for five repetitions, n = 20) or MCT (sustained 60 % VO_2max, n = 20) for 30 min/day, 5 days/week for 6 weeks, or to a control group (CTL) that did not received exercise intervention (n = 20). Mon-EPC characteristics and EPC functionality under hypoxic exercise (HE, 100 W under 12 % O₂) were determined before and after HIT, MCT, and CTL.

RESULTS

The results demonstrated that after the intervention, the HIT group exhibited larger improvements in VO_2peak, estimated peak cardiac output (Q_C), and estimated peak perfusions of frontal cerebral lobe (Q_FC) and vastus lateralis (Q_VL) than the MCT group. Furthermore, HIT (a) increased circulating CD14⁺⁺/CD16^-/CD34⁺/KDR⁺ (Mon-1 EPC) and CD14⁺⁺/CD16⁺/CD34⁺/KDR⁺ (Mon-2 EPC) cell counts, (b) promoted the migration and tube formation of EPCs, (c) diminished the shedding of endothelial (CD34^-/KDR⁺/phosphatidylserine⁺) cells, and (d) elevated plasma nitrite plus nitrate, stromal cell-derived factor-1, matrix metalloproteinase-9, and vascular endothelial growth factor-A concentrations at rest or following HE, compared to those of MCT. In addition, Mon-1 and -2 EPC counts were directly related to VO_2peak and estimated peak Q_C, Q_FC, and Q_VL.

CONCLUSIONS

HIT is superior to MCT for improving hemodynamic adaptation and Mon-EPC production. Moreover, HIT effectively enhances EPC functionality and suppresses endothelial injury undergoing hypoxia.

Effects of endurance and high intensity training on ICAM-1 and VCAM-1 levels and arterial pressure in obese and normal weight adolescents

OBJECTIVES

Obesity prevalence has increased in Iranian adolescents in recent years. However, few studies have examined the impact of intervention programs on this health issue. The main objective of this study was to evaluate the effects of 8-week endurance training (ET) and high intensity interval training (HIIT) on intercellular adhesion molecule-1(ICAM-1) and vascular adhesion molecule-1(VCAM-1) levels among obese and normal-weight male adolescents.

METHODS

Thirty obese and 30 normal-weight subjects were assigned to the ET, HIIT, or control group for eight weeks. Before and after the intervention, ICAM-1, VCAM-1, body weight, BMI, VO2max, and blood pressures were measured. SPSS (Version 21) was used for data analysis, and the significance level was set at p < 0.05.

RESULTS

Mixed design ANOVAs indicated that the obese participants had significantly (p < 0.05) lower ICAM-1 levels in the ET (from 509 ± 61 ng/ml to 387 ± 43 ng/ml) and HIIT (from 517 ± 72 ng/ml to 374 ± 50 ng/ml), but their VCAM-1 level was significantly (p < 0.05) reduced only after the HIIT (from 1689 ± 119 ng/ml to 1282 ± 63 ng/ml). Similarly, normal weight participants significantly (p < 0.05) lowered their ICAM-1 levels in the ET (from 296 ± 18 ng/ml to 216 ± 14 ng/ml) and HIIT (from 289 ± 22 ng/ml to 202 ± 12 ng/ml), but their VCAM-1 level was significantly (p < 0.05) reduced only after the HIIT (from 895 ± 50 ng/ml to 673 ± 142 ng/ml). Systolic blood pressure and diastolic blood pressures of all the participants were significantly (p < 0.01) decreased at the conclusion of the ET and HIIT.

CONCLUSION

While both the ET and HIIT were useful in lowering the SBP and DBP of the participants, HIIT was more effective than ET in reducing ICAM-1 and VCAM-1 content in normal and obese adolescents.

Comparing exercise training modalities in heart failure: A systematic review and meta-analysis

Exercise training (ET) is suggested to improve exercise capacity, prognosis, quality of life (QOL) and functional modifications of the heart in patients with heart failure (HF). However, it is not clear which modality is best. In order to assess the effectiveness of different ET modalities on prognostic cardiopulmonary exercise test (CPET) parameters, QOL and left ventricular remodeling, a systematic review and meta-analysis was performed. Randomized clinical trials (RCTs) were selected in three databases. The primary outcome data were peak oxygen uptake, ventilation over carbon dioxide slope, oxygen uptake efficiency slope, exercise oscillatory ventilation, rest and peak pulmonary end-tidal CO2. Secondary variables were QOL, left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD). Twenty RCTs (n=811) met the a priori stated inclusion criteria. Studies were categorized into four different groups: "interval training (IT1) versus combined interval and strength training (IT1S)" (n=156), "continuous training (CT1) versus combined continuous and strength training (CT1S)" (n=130), "interval training (IT2) versus continuous training (CT2)" (n=501) and "continuous training (CT3) versus strength training (S3)" (n=24). No significant random effects of exercise modality were revealed assessing the CPET parameters. There was a significant improvement in QOL applying CT1S (P<0.001). Comparing IT2 with CT2, LVEDD and LVEF were significantly improved favoring IT2 (P<0.001). There is some evidence to support that interval training is more effective to improve LVEF and LVEDD. The fact that patients with HF are actively involved in any kind of ET program seems sufficient to improve the prognosis, QOL and anatomic function.

Aerobic Interval Training Elicits Different Hemodynamic Adaptations Between Heart Failure Patients with Preserved and Reduced Ejection Fraction

OBJECTIVE

This investigation explored how aerobic interval training influences central or peripheral hemodynamic response(s) to exercise in patients with heart failure (HF) with preserved ejection fraction (HFpEF) or those with HF with reduced ejection fraction (HFrEF).

DESIGN

One hundred twenty HF patients were divided into four groups: HFpEF and HFrEF with aerobic interval training (3-min intervals at 40% and 80% VO2peak for 30 mins/day, 3 days/wk for 12 wks) and general health care groups. Exercise hemodynamics in the heart, frontal cerebral lobe, and vastus lateralis muscle, and oxygenation in the frontal cerebral lobe and vastus lateralis muscle were measured before and after the intervention.

RESULTS

Aerobic interval training significantly (1) improved pumping function with enhanced peak cardiac power index in the HFrEF group and improved diastolic function with reduction of the E/E' ratio in the HFpEF group, (2) increased blood distribution to the frontal cerebral lobe/vastus lateralis muscle and O2 extraction by vastus lateralis muscle during exercise in the HFpEF group compared with the HFrEF group, (3) heightened VO2peak in both HFpEF and HFrEF groups and lowered the VE/VCO2 slope in the HFpEF group, and (4) increased the Short Form-36 physical/mental component scores and decreased the Minnesota Living with Heart Failure questionnaire score in both HFpEF and HFrEF groups.

CONCLUSIONS

Aerobic interval training effectively enhances cardiac hemodynamic response to exercise in HFrEF patients while increasing the delivery/use of O2 to exercising skeletal muscles and frontal cerebral lobe tissues in HFpEF patients, thereby improving global/disease-specific quality-of-life measures in these HF patients.

Akt/mTOR pathway contributes to skeletal muscle anti-atrophic effect of aerobic exercise training in heart failure mice

BACKGROUND

Exercise intolerance is one of the main clinical symptoms of heart failure (HF) and is associated with skeletal muscle wasting due to an imbalance between proteolysis and protein synthesis. In this study, we tested whether aerobic exercise training (AET) would counteract skeletal muscle atrophy by activating IGF-I/Akt/mTOR pathway in HF mice.

METHODS

Sympathetic hyperactivity induced HF mice were assigned into 8-week moderate intensity AET. Untrained wild type and HF mice were used as control. Soleus cross sectional area was evaluated by histochemistry and motor performance by rotarod. 26S proteasome activity was assessed by fluorimetric assay, and components of IGF-I/Akt/mTOR pathway or myostatin pathway by qRT-PCR or immunoblotting. A different subset of mice was used to evaluate the relative contribution of mTOR inhibition (rapamycin) or activation (leucine) on AET-induced changes in muscle mass regulation.

RESULTS

AET prevented exercise intolerance and impaired motor performance in HF mice. These effects were associated with attenuation of soleus atrophy. Rapamycin treatment precluded AET effects on soleus mass in HF mice suggesting the involvement of IGF signaling pathway in this response. In fact, AET increased IGF-I Ea and IGF-I Pan mRNA levels, while it reduced myostatin and Smad2 mRNA levels in HF mice. At protein levels, AET prevented reduced expression levels of IGF-I, pAkt (at basal state), as well as, p4E-BP1 and pP70(S6K) (leucine-stimulated state) in HF mice. Additionally, AET prevented 26S proteasome hyperactivity in HF mice.

CONCLUSIONS

Taken together, our data provide evidence for AET-induced activation of IGF-I/Akt/mTOR signaling pathway counteracting HF-induced muscle wasting.

Cardiac Rehabilitation in Patients With Heart Failure: New Perspectives in Exercise Training

Exercise training is recommended to patients with chronic heart failure (CHF) and reduced ejection fraction at a class 1 evidence level. Currently the 'dose' of exercise (dose being both volume and intensity) still remains uncertain and the best form of aerobic exercise training has not been defined. Guidelines commonly use heart rate (HR) as a target factor for both moderate continuous and interval training exercises. However, exercise training guided by HR can be limited in CHF patients due to chronotropic incompetence and beta-blocker treatment. In our study, we systematically addressed the above issues by applying a training method that takes into account both the volume and intensity of exercise on an individual basis. This method is referred to as individual TRaining IMPulses (TRIMPi). In this review, we summarise a series of investigations that used TRIMPi and different exercise forms to quantify the optimum training load in CHF patients. This review also highlights the way TRIMPi and the individual exercise dose affects cardiorespiratory, metabolic and autonomic cardiac adaptations.

Long-term moderate treadmill exercise promotes stress-coping strategies in male and female rats

Recent evidence has revealed the impact of exercise in alleviating anxiety and mood disorders; however, the exercise protocol that exerts such benefit is far from known. The current study was aimed to assess the effects of long-term moderate exercise on behavioural coping strategies (active vs. passive) and Hypothalamic-Pituitary-Adrenal response in rats. Sprague-Dawley male and female rats were exposed to 32-weeks of treadmill exercise and then tested for two-way active avoidance learning (shuttle-box). Two groups were used as controls: a non-handled sedentary group, receiving no manipulation, and a control group exposed to a stationary treadmill. Female rats displayed shorter escape responses and higher number of avoidance responses, reaching criterion for performance earlier than male rats. In both sexes, exercise shortened escape latencies, increased the total number of avoidances and diminished the number of trials needed to reach criterion for performance. Those effects were greater during acquisition in female rats, but remained over the shuttle-box sessions in treadmill trained male rats. In females, exercise did not change ACTH and corticosterone levels after shuttle-box acquisition. Collectively, treadmill exercise improved active coping strategies in a sex-dependent manner. In a broader context, moderate exercise could serve as a therapeutic intervention for anxiety and mood disorders.

Modulation of angiotensin II signaling following exercise training in heart failure

Sympathetic activation is a consistent finding in the chronic heart failure (CHF) state. Current therapy for CHF targets the renin-angiotensin II (ANG II) and adrenergic systems. Angiotensin converting enzyme (ACE) inhibitors and ANG II receptor blockers are standard treatments along with β-adrenergic blockade. However, the mortality and morbidity of this disease is still extremely high, even with good medical management. Exercise training (ExT) is currently being used in many centers as an adjunctive therapy for CHF. Clinical studies have shown that ExT is a safe, effective, and inexpensive way to improve quality of life, work capacity, and longevity in patients with CHF. This review discusses the potential neural interactions between ANG II and sympatho-excitation in CHF and the modulation of this interaction by ExT. We briefly review the current understanding of the modulation of the angiotensin type 1 receptor in sympatho-excitatory areas of the brain and in the periphery (i.e., in the carotid body and skeletal muscle). We discuss possible cellular mechanisms by which ExT may impact the sympatho-excitatory process by reducing oxidative stress, increasing nitric oxide. and reducing ANG II. We also discuss the potential role of ACE2 and Ang 1-7 in the sympathetic response to ExT. Fruitful areas of further investigation are the role and mechanisms by which pre-sympathetic neuronal metabolic activity in response to individual bouts of exercise regulate redox mechanisms and discharge at rest in CHF and other sympatho-excitatory states.

Exercise training prevents the deterioration in the arterial baroreflex control of sympathetic nerve activity in chronic heart failure patients

Arterial baroreflex control of muscle sympathetic nerve activity (ABRMSNA) is impaired in chronic systolic heart failure (CHF). The purpose of the study was to test the hypothesis that exercise training would improve the gain and reduce the time delay of ABRMSNA in CHF patients. Twenty-six CHF patients, New York Heart Association Functional Class II-III, EF ≤ 40%, peak V̇o2 ≤ 20 ml·kg(-1)·min(-1) were divided into two groups: untrained (UT, n = 13, 57 ± 3 years) and exercise trained (ET, n = 13, 49 ± 3 years). Muscle sympathetic nerve activity (MSNA) was directly recorded by microneurography technique. Arterial pressure was measured on a beat-to-beat basis. Time series of MSNA and systolic arterial pressure were analyzed by autoregressive spectral analysis. The gain and time delay of ABRMSNA was obtained by bivariate autoregressive analysis. Exercise training was performed on a cycle ergometer at moderate intensity, three 60-min sessions per week for 16 wk. Baseline MSNA, gain and time delay of ABRMSNA, and low frequency of MSNA (LFMSNA) to high-frequency ratio (HFMSNA) (LFMSNA/HFMSNA) were similar between groups. ET significantly decreased MSNA. MSNA was unchanged in the UT patients. The gain and time delay of ABRMSNA were unchanged in the ET patients. In contrast, the gain of ABRMSNA was significantly reduced [3.5 ± 0.7 vs. 1.8 ± 0.2, arbitrary units (au)/mmHg, P = 0.04] and the time delay of ABRMSNA was significantly increased (4.6 ± 0.8 vs. 7.9 ± 1.0 s, P = 0.05) in the UT patients. LFMSNA-to-HFMSNA ratio tended to be lower in the ET patients (P < 0.08). Exercise training prevents the deterioration of ABRMSNA in CHF patients.

Both food restriction and high-fat diet during gestation induce low birth weight and altered physical activity in adult rat offspring: the "Similarities in the Inequalities" model

We have previously described a theoretical model in humans, called "Similarities in the Inequalities", in which extremely unequal social backgrounds coexist in a complex scenario promoting similar health outcomes in adulthood. Based on the potential applicability of and to further explore the "similarities in the inequalities" phenomenon, this study used a rat model to investigate the effect of different nutritional backgrounds during gestation on the willingness of offspring to engage in physical activity in adulthood. Sprague-Dawley rats were time mated and randomly allocated to one of three dietary groups: Control (Adlib), receiving standard laboratory chow ad libitum; 50% food restricted (FR), receiving 50% of the ad libitum-fed dam's habitual intake; or high-fat diet (HF), receiving a diet containing 23% fat. The diets were provided from day 10 of pregnancy until weaning. Within 24 hours of birth, pups were cross-fostered to other dams, forming the following groups: Adlib_Adlib, FR_Adlib, and HF_Adlib. Maternal chow consumption and weight gain, and offspring birth weight, growth, physical activity (one week of free exercise in running wheels), abdominal adiposity and biochemical data were evaluated. Western blot was performed to assess D2 receptors in the dorsal striatum. The "similarities in the inequalities" effect was observed on birth weight (both FR and HF groups were smaller than the Adlib group at birth) and physical activity (both FR_Adlib and HF_Adlib groups were different from the Adlib_Adlib group, with less active males and more active females). Our findings contribute to the view that health inequalities in fetal life may program the health outcomes manifested in offspring adult life (such as altered physical activity and metabolic parameters), probably through different biological mechanisms.

Obligatory role of neuronal nitric oxide synthase in the heart's antioxidant adaptation with exercise

Excessive oxidative stress in the heart results in contractile dysfunction. While antioxidant therapies have been a disappointment clinically, exercise has shown beneficial results, in part by reducing oxidative stress. We have previously shown that neuronal nitric oxide synthase (nNOS) is essential for cardioprotective adaptations caused by exercise. We hypothesize that part of the cardioprotective role of nNOS is via the augmentation of the antioxidant defense with exercise by positively shifting the nitroso-redox balance. Our results show that nNOS is indispensable for the augmented anti-oxidant defense with exercise. Furthermore, exercise training of nNOS knockout mice resulted in a negative shift in the nitroso-redox balance resulting in contractile dysfunction. Remarkably, overexpressing nNOS (conditional cardiac-specific nNOS overexpression) was able to mimic exercise by increasing VO2max. This study demonstrates that exercise results in a positive shift in the nitroso-redox balance that is nNOS-dependent. Thus, targeting nNOS signaling may mimic the beneficial effects of exercise by combating oxidative stress and may be a viable treatment strategy for heart disease.