Natriuretic peptide response to dynamic exercise in patients with atrial fibrillation

Highlighting the idea of exerkines in the management of cancer patients with cachexia: novel insights and a critical review

BACKGROUND

Exerkines are all peptides, metabolites, and nucleic acids released into the bloodstream during and after physical exercise. Exerkines liberated from skeletal muscle (myokines), the heart (cardiokines), liver (hepatokines), white adipose tissue (adipokines), brown adipose tissue (batokines), and neurons (neurokines) may benefit health and wellbeing. Cancer-related cachexia is a highly prevalent disorder characterized by weight loss with specific skeletal muscle and adipose tissue loss. Many studies have sought to provide exercise strategies for managing cachexia, focusing on musculoskeletal tissue changes. Therefore, understanding the responses of musculoskeletal and other tissue exerkines to acute and chronic exercise may provide novel insight and recommendations for physical training to counteract cancer-related cachexia.

METHODS

For the purpose of conducting this study review, we made efforts to gather relevant studies and thoroughly discuss them to create a comprehensive overview. To achieve this, we conducted searches using appropriate keywords in various databases. Studies that were deemed irrelevant to the current research, not available in English, or lacking full-text access were excluded. Nevertheless, it is important to acknowledge the limited amount of research conducted in this specific field.

RESULTS

In order to obtain a comprehensive understanding of the findings, we prioritized human studies in order to obtain results that closely align with the scope of the present study. However, in instances where human studies were limited or additional analysis was required to draw more robust conclusions, we also incorporated animal studies. Finally, 295 studies, discussed in this review.

CONCLUSION

Our understanding of the underlying physiological mechanisms related to the significance of investigating exerkines in cancer cachexia is currently quite basic. Nonetheless, this demonstrated that resistance and aerobic exercise can contribute to the reduction and control of the disease in individuals with cancer cachexia, as well as in survivors, by inducing changes in exerkines.

Effect of adrenaline on serum mid-regional pro-atrial natriuretic peptide and central blood volume

New Findings

What is the central question in this study?

Atrial natriuretic peptide (ANP) is secreted in response to atrial wall distension and thus allows for evaluation, albeit indirect, of the central blood volume. Adrenaline has chronotropic and inotropic effects. We evaluated whether the chronotropic and inotropic effects of adrenaline were reflected in mid‐regional proANP.

What is the main finding and its importance?

Central blood volume remained stable with infusion of adrenaline and yet mid‐regional proANP increased. Thus, the chronotropic and inotropic state of the heart or adrenaline directly induces release of ANP variants from the myocytes.

Abstract

Atrial natriuretic peptide (ANP) has vasodilatory, natriuretic and diuretic properties. It is secreted in response to atrial wall distension and thereby provides an indirect evaluation of central blood volume (CBV). Adrenaline has chronotropic and inotropic effects that increase cardiac output. In the present study, we evaluated whether these effects were influenced by an increase in CBV and reflected in mid‐regional proANP (MR‐proANP) concentrations in the circulation, a stable proxy marker of bioactive ANP. Changes in CBV were evaluated by thoracic electrical admittance and haemodynamic variables monitored by pulse‐contour analysis during two intervals with graded infusion of adrenaline. Adrenaline infusion increased heart rate (by 33 ± 18%) and stroke volume (by 6 ± 13%), hence cardiac output (by 42 ± 23%; all P < 0.05). The increase in cardiac output did not result from an increase in CBV, because thoracic electrical admittance remained stable (−3 ± 17%; P = 0.230). Serum MR‐proANP concentrations were increased (by 26 ± 25%; P < 0.001) by adrenaline infusion and remained elevated 60 min postinfusion. We conclude that MR‐proANP in the circulation is affected not only by CBV, but also by increased chronotropy/inotropy of the heart, or that adrenaline directly induces release of ANP variants from the myocytes.

Natriuretic peptides in the control of lipid metabolism and insulin sensitivity

Natriuretic peptides have long been known for their cardiovascular function. However, a growing body of evidence emphasizes the role of natriuretic peptides in human substrate and energy metabolism, thereby connecting the heart with several insulin-sensitive organs like adipose tissue, skeletal muscle and liver. Obesity may be associated with an impaired regulation of the natriuretic peptide system, also indicated as a natriuretic handicap. Evidence points towards a contribution of this natriuretic handicap to the development of obesity, type 2 diabetes mellitus and cardiometabolic complications, although the causal relationship is not fully understood. Nevertheless, targeting the natriuretic peptide pathway may improve metabolic health in obesity and type 2 diabetes mellitus. This review will focus on current literature regarding the metabolic roles of natriuretic peptides with emphasis on lipid metabolism and insulin sensitivity. Furthermore, it will be discussed how exercise and lifestyle intervention may modulate the natriuretic peptide-related metabolic effects.

The Effects of Exercise on Natriuretic Peptides in Individuals without Heart Failure

Cardiac natriuretic peptides (NPs) play an important role in the regulation of energy expenditure in skeletal muscle and adipose tissue. A systematic review on the effects of exercise on NPs in patients with heart failure reported that aerobic and resistance training reduced NPs; however, the effects of exercise on NPs and the underlying mechanism of exercise-induced NP secretion in subjects without heart failure remain unknown. In athletes and young, healthy subjects, the NP concentration at rest is not elevated, but strenuous endurance exercise significantly increases NPs. The exercise-induced increase in NPs may be caused by transient myocardial wall stress, cardiomyocyte metabolic changes, or neuroendocrinological response, which may have cytoprotective and growth-regulating effects on the heart. On the other hand, in elderly, overweight/obese subjects, and patients with hypertension, NP concentrations also increase during exercise; however, NP secretion may be more susceptible to cardiac stress compared to young, healthy individuals. Recent studies have shown that NPs are associated with thermogenesis in fat tissue and oxidative capacity in skeletal muscles. NPs may also have a protective role for skeletal muscle in humans, although further studies are warranted to elucidate the physiological mechanism of exercise-induced NP secretion.

Plasma brain natriuretic peptide concentrations in patients with valvular heart disease

Objective

Plasma brain natriuretic peptide (BNP) concentrations predict prognosis in patients with valvular heart disease (VHD), but it is unclear whether this directly relates to disease severity. We assessed the relationship between BNP and echocardiographic measures of disease severity in patients with VHD.

Methods

Plasma BNP concentrations were measured in patients with normal left ventricular (LV) systolic function and isolated VHD (mitral regurgitation (MR), n=33; aortic regurgitation (AR), n=39; aortic stenosis (AS), n=34; mitral stenosis (MS), n=30), and age-matched and sex-matched controls (n=39) immediately prior to exercise stress echocardiography.

Results

Compared with controls, patients with VHD had elevated plasma BNP concentrations (MR median 35 (IQR 23–52), AR 34 (22–45), AS 31 (22–60), MS 58 (34–90); controls 24 (16–33) pg/mL; p<0.01 for all). LV end diastolic volume index varied by valve lesion; (MR (mean 77±14), AR (91±28), AS (50±17), MS (43±11), controls (52±13) mL/m²; p<0.0001). There were no associations between LV volume and BNP. Left atrial (LA) area index varied (MR (18±4 cm²/m²), AR (12±2), AS (11±3), MS (19±6), controls (11±2); p<0.0001), but correlated with plasma BNP concentrations: MR (r=0.42, p=0.02), MS (r=0.86, p<0.0001), AR (r=0.53, p=0.001), AS (r=0.52, p=0.002). Higher plasma BNP concentrations were associated with increased pulmonary artery pressure and reduced exercise capacity. Despite adverse cardiac remodelling, 81 (60%) patients had a BNP concentration within the normal range.

Conclusions

Despite LV remodelling, plasma BNP concentrations are often normal in patients with VHD. Conversely, mild elevations of BNP occur with LA dilatation in the presence of normal LV. Plasma BNP concentrations should be interpreted with caution when assessing patients with VHD.

Stroke and Death Prediction with the Impact of Vascular Disease in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia encountered in the U.S. and the growing burden of AF has profound health implications due to the association of AF with an increased risk of stroke, heart failure, and mortality. AF is a significant risk factor for thromboembolic stroke; and also independently increases total mortality in patients with and without cardiovascular disease. Various risk stratification schemes such as CHADS₂ and CHA₂DS₂-VASc have been implemented in clinical practice to determine the risk of cardio-embolic stroke, and need for thrombo-prophylaxis in patients with AF. AF is also closely related to the pathophysiology of other cardiovascular and peripheral vascular disease. Many patients with AF have associated atherosclerosis given that many risk factors for atherosclerosis also predispose to AF. Myocardial infarction (MI) is also closely related to AF and its clinical course is affected by new onset AF. This review elucidates the impact of AF on major adverse cardiovascular events and mortality outcomes in relation to stroke, coronary artery disease and peripheral vascular disease.

Involvement of the atrial natriuretic peptide in cardiovascular pathophysiology and its relationship with exercise

In this minireview we describe the involvement of the atrial natriuretic peptide (ANP) in cardiovascular pathophysiology and exercise. The ANP has a broad homeostatic role and exerts complex effects on the cardio-circulatory hemodynamics, it is produced by the left atrium and has a key role in regulating sodium and water balance in mammals and humans. The dominant stimulus for its release is atrial wall tension, commonly caused by exercise. The ANP is involved in the process of lipolysis through a cGMP signaling pathway and, as a consequence, reducing blood pressure by decreasing the sensitivity of vascular smooth muscle to the action of vasoconstrictors and regulate fluid balance. The increase of this hormone is associated with better survival in patients with chronic heart failure (CHF). This minireview provides new evidence based on recent studies related to the beneficial effects of exercise in patients with cardiovascular disease, focusing on the ANP.

N-terminal pro-atrial natriuretic peptide response to acute exercise in depressed patients and healthy controls

BACKGROUND

The dysfunction of hypothalamic-pituitary-adrenal (HPA) axis in major depression includes hyperactivity and reduced feedback inhibition. Atrial natriuretic peptide (ANP) is able to reduce the HPA-axis response to stress and has an anxiolytic effect in rodents and humans. We hypothesized that patients with depression would have an attenuated N-terminal proANP (NT-proANP) response to acute exercise compared to healthy controls. Secondly, we aimed to assess the effect of antidepressants on NT-proANP response to acute exercise.

METHODS

We examined 132 outpatients with mild to moderate depression (ICD-10) and 44 healthy controls, group matched for age, sex, and BMI. We used an incremental bicycle ergometer test as a physical stressor. Blood samples were drawn at rest, at exhaustion, and 15, 30, and 60 min post-exercise.

RESULTS

The NT-proANP response to physical exercise differed between depressed subjects and healthy controls (group×time; F(4,162.9)=10.92; p<0.001). The increase from rest to VO(2max) was 0.98 (SD 0.8) and 1.96 nmol/l (SD 1.1), respectively, for depressed subjects and healthy controls (mean diff: 0.98 nmol/l; 95% CI 0.7-1.3; t=6.63; df=170; p<0.001). The increase in NT-proANP from rest to peak VO(2max) was 1.27 (SD 1.0) and 0.84 nmol/l (SD 0.6), respectively, for unmedicated and medicated patients (mean diff: 0.42 nmol/l; 95% CI 0.1-0.8; t=2.56; df=128; p=0.01).

CONCLUSION

We observed an attenuated NT-proANP response to acute physical stress in depressed patients. Antidepressants were associated with an independent suppressive effect on the NT-proANP response.

Sinus rhythm restoration after atrial fibrillation: the clinical value of N-terminal pro-BNP measurements

AIM

To examine the effects of sinus rhythm (SR) restoration on N-Terminal pro-BNP (NTP-BNP) in patients with atrial fibrillation (AF).

METHODS

Subjects with paroxysmal and persistent AF and absence of organic heart disease were prospectively studied. Chemical or electrical restoration of SR was attempted within 48 hours (n = 37) or >3 weeks (n = 73). Clinical and laboratory (NTP-BNP, 72-hour Holter monitor, and electrocardiogram) assessment were obtained at baseline and at 1, 30, and 180 days after SR restoration. Patients were divided into three predefined "outcome groups": (a) maintenance of SR for 1 month, (b) SR with recurrent paroxysmal AF (PaAF), and (c) early (<30 days) recurrence persistent AF (RAF).

RESULTS

Of the 110 patients enrolled, 89 had initial successful SR restoration. Baseline NTP-BNP was 936 pg/mL (interquartile range (IQR) 333-2,026); ratio between baseline and 30-day NTP-BNP was 10.2 (IQR 6.42-22.0) for SR group, 3.3 (IQR 2.45-7.34) for PaAF, and 1.07 (IQR 0.87-1.22) for RAF (P < 0.001). Patients with ratio </=3 were more likely to have PaAF (46% vs 3%, OR 30, P < 0.001).

CONCLUSION

With SR restoration, NTP-BNP decline is observed up to 1 month. NTP-BNP drop is partially or completely abolished by PaAF and RAF, respectively. NTP-BNP does not predict successful SR restoration.

Metabolic regulation: effects of natriuretic peptide interactions

In addition to their well-established effects on blood pressure and volume homeostasis, natriuretic peptides have complex effects on carbohydrate and lipid metabolism. In vivo, pharmacological and physiological concentrations of atrial natriuretic peptides induce lipolysis in a concentration-dependent manner and increase the lipid oxidation rate. The response appears to be mediated through the stimulation of natriuretic peptide receptor-A. More recent studies suggest that natriuretic peptides also affect the production of several adipokines. These mechanisms may be relevant, as natriuretic peptide availability is altered in numerous physiological and pathological conditions, including physical exercise, congestive heart failure and obesity.

Effect of exercise training on cardiac oxytocin and natriuretic peptide systems in ovariectomized rats

Exercise training results in cardiovascular and metabolic adaptations that may be beneficial in menopausal women by reducing blood pressure, insulin resistance, and cholesterol level. The adaptation of the cardiac hormonal systems oxytocin (OT), natriuretic peptides (NPs), and nitric oxide synthase (NOS) in response to exercise training was investigated in intact and ovariectomized (OVX) rats. Ovariectomy significantly augmented body weight (BW), left ventricle (LV) mass, and intra-abdominal fat pad weight and decreased the expression of oxytocin receptor (OTR), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and guanylyl cyclase-A (GC-A), in the right atrium (RA) and LV, indicating estrogenic control of these genes. These effects of ovariectomy were counteracted by 8-wk-long exercise training which decreased fat pad weight (33.4 +/- 2.3 to 23.4 +/- 3.1 g, n = 8, P < 0.05), plasma free fatty acids (0.124 +/- 0.033 to 0.057 +/- 0.010 mM, n = 8, P < 0.01), and plasma triacylglycerol (0.978 +/- 0.174 to 0.588 +/- 0.115 mM, n = 8, P < 0.05). Chronic exercise tended to decrease BW and stimulated ANP (4- to 5-fold) and OTR gene expression in the LV and RA and BNP and inducible NOS (iNOS) mRNA in the LV. In sham-operated rats, exercise augmented ANP expression in the RA, downregulated GC-A mRNA in the LV and RA, but increased its expression threefold in the RA of OVX animals. Endothelial NOS and iNOS expression was enhanced in the left atrium of sham-operated rats. Altogether, these data indicate that in OVX animals, chronic exercise significantly enhances cardiac OT, NPs, and NOS, thus implicating all three hormonal systems in the beneficial effects of exercise training.

NT-pro-BNP is associated with long-term outcome in a heterogeneous sample of cardiac inpatients

BACKGROUND

B-type natriuretic peptides (NP) are excellent predictors of mortality in selected patients with heart failure and coronary heart disease. Up to now, the association of NPs with cardiovascular outcome has not been evaluated in multi-morbid populations with a broad spectrum of cardiovascular disease.

METHODS

NT-pro-BNP was measured at discharge in 615 inpatients from a cardiology department of a university hospital. The association of discharge NT-pro-BNP with long-term outcome was examined during a median follow-up time of 1130 days.

RESULTS

NT-pro-BNP was significantly elevated in patients who died, developed ischemic stroke, or were hospitalized due to acute heart failure, but not in patients who developed myocardial infarction or underwent coronary angioplasty compared to patients without any endpoint. Patients with supramedian NT-pro-BNP values (>339 pg/ml) had significantly worse outcomes with respect to the combined endpoint (CE) of death, heart failure hospitalization, and stroke than patients with inframedian NT-pro-BNP values. After adjusting for age, gender, renal function, NYHA class, presence of diabetes, coronary 3-vessel disease, systolic and valvular dysfunction, NT-pro-BNP was a significant predictor of the CE. The AUC for NT-pro-BNP to predict the CE was 0.79 in the total population, 0.81 in patients with coronary heart disease or acute heart failure, and 0.74 in patients with other diagnoses. A NT-pro-BNP cut-off value of 240 pg/ml revealed a negative predictive value of more than 93% in all three groups.

CONCLUSION

In a heterogeneous population of hospitalized cardiac patients, NT-pro-BNP measured at discharge predicts a poor cardiovascular outcome, independently of the cardiologic diagnosis and traditional risk factors.

[Atrial fibrillation]

Atrial fibrillation represents the arrhythmia that most frequently leads to hospital admission. Due to the age structure of our population and the increasing morbidity and comorbidity, one has to assume that this arrhythmia will reach an even higher prevalence. The therapeutic successes are often insufficient. First of all, it is important to diagnose and treat the underlying disease. Secondly, antiarrhythmic therapy has to be considered in symptomatic patients. In those patients and in the case of a persistent form, electrical cardioversion should be performed. Repetitive cardioversions in asymptomatic patients yield no advantage for mortality. Antiarrhythmic therapy consists of drugs of the classes Ia, Ic, and III. Concomitant anticoagulation is necessary; ASS in indicated only in patients without structural heart disease and lacking thromboembolic risk factors. If risk factors are present, effective therapy with coumarin derivatives is required. Therapy with ACE inhibitors and AT blockers leads to an advantage in patients with arterial hypertension and/or heart failure concerning the stability of sinus rhythm after cardioversion and the incidence of arrhythmia. Newer medications for anticoagulation and newer antiarrhythmic drugs raise the hope of a future therapy with higher efficacy and lower rate of side effects.