Adrenergic signaling in heart failure and cardiovascular aging

Heart failure management with β-blockers: can we do better?

Heart failure (HF) is associated with disabling symptoms, poor quality of life, and a poor prognosis with substantial excess mortality in the years following diagnosis. Overactivation of the sympathetic nervous system is a key feature of the pathophysiology of HF and is an important driver of the process of adverse remodelling of the left ventricular wall that contributes to cardiac failure. Drugs which suppress the activity of the renin-angiotensin-aldosterone system, including β-blockers, are foundation therapies for the management of heart failure with reduced ejection fraction (HFrEF) and despite a lack of specific outcomes trials, are also widely used by cardiologist in patients with HF with preserved ejection fraction (HFpEF). Today, expert opinion has moved away from recommending that treatment for HF should be guided solely by the LVEF and interventions should rather address signs and symptoms of HF (e.g. oedema and tachycardia), the severity of HF, and concomitant conditions. β-blockers improve HF symptoms and functional status in HF and these agents have demonstrated improved survival, as well as a reduced risk of other important clinical outcomes such as hospitalisation for heart failure, in randomised, placebo-controlled outcomes trials. In HFpEF, β-blockers are anti-ischemic and lower blood pressure and heart rate. Moreover, β-blockers also reduce mortality in the setting of HF occurring alongside common comorbid conditions, such as diabetes, CKD (of any severity), and COPD. Higher doses of β-blockers are associated with better clinical outcomes in populations with HF, so that ensuring adequate titration of therapy to their maximal (or maximally tolerated) doses is important for ensuring optimal outcomes for people with HF. In principle, a patient with HF could have combined treatment with a β-blocker, renin-angiotensin-aldosterone system inhibitor/neprilysin inhibitor, mineralocorticoid receptor antagonist, and a SGLT2 inhibitor, according to tolerability.

Former smoking associated with epigenetic modifications in human granulosa cells among women undergoing assisted reproduction

Smoking exposure during adulthood can disrupt oocyte development in women, contributing to infertility and possibly adverse birth outcomes. Some of these effects may be reflected in epigenome profiles in granulosa cells (GCs) in human follicular fluid. We compared the epigenetic modifications throughout the genome in GCs from women who were former (N = 15) versus never smokers (N = 44) undergoing assisted reproductive technologies (ART). This study included 59 women undergoing ART. Smoking history including time since quitting was determined by questionnaire. GCs were collected during oocyte retrieval and DNA methylation (DNAm) levels were profiled using the Infinium MethylationEPIC BeadChip. We performed an epigenome-wide association study with robust linear models, regressing DNAm level at individual loci on smoking status, adjusting for age, ovarian stimulation protocol, and three surrogate variables. We performed differentially methylated regions (DMRs) analysis and over-representation analysis of the identified CpGs and corresponding gene set. 81 CpGs were differentially methylated among former smokers compared to never smokers (FDR < 0.05). We identified 2 significant DMRs (KCNQ1 and RHBDD2). The former smoking-associated genes were enriched in oxytocin signaling, adrenergic signaling in cardiomyocytes, platelet activation, axon guidance, and chemokine signaling pathway. These epigenetic variations have been associated with inflammatory responses, reproductive outcomes, cancer development, neurodevelopmental disorder, and cardiometabolic health. Secondarily, we examined the relationships between time since quitting and DNAm at significant CpGs. We observed three CpGs in negative associations with the length of quitting smoking (p < 0.05), which were cg04254052 (KCNIP1), cg22875371 (OGDHL), and cg27289628 (LOC148145), while one in positive association, which was cg13487862 (PLXNB1). As a pilot study, we demonstrated epigenetic modifications associated with former smoking in GCs. The study is informative to potential biological pathways underlying the documented association between smoking and female infertility and biomarker discovery for smoking-associated reproductive outcomes.

Effects of alpha-adrenergic receptor blockade on coronary circulation in postmenopausal women

We sought to investigate the effect of the α1-adrenergic receptor blockade during handgrip exercise (Grip), isolated metaboreflex activation (Metabo), and cold pressor test (CPT) on coronary circulation in young (YW) and postmenopausal women (PMW). Ten YW and 9 PMW underwent two protocols: (1) 3 min of baseline followed by 3 min of CPT and (2) 3 min of rest, 3 min of Grip followed by 3 min of Metabo. Protocols were carried out under control conditions and α1-adrenergic receptor blockade (oral prazosin 0.03 mg·kg-1). Coronary blood velocity (CBV) and vascular conductance (CCI) were lower in PMW. Grip increased CBV only in YW (YW: Δ18.0 ± 21.1% vs. PMW: Δ4.2 ± 10.1%; p < 0.05), and the blockade did not change the CBV response to Grip in YW and PMW. During the Metabo, CBV returned to resting levels in YW and was unchanged from rest in PMW, before (YW:Δ1.7 ± 8.7% vs. PMW: Δ- 1.5 ± 8.6) and under the blockade (YW: Δ4.5 ± 14.8% vs. PMW: Δ9.1 ± 29.5%). CPT did not change CBV in both groups (YW: Δ3.9 ± 8.0 vs. PMW: Δ- 4.1 ± 6.2%), following the α1-blockade, CPT increased CBV only in YW (YW: Δ11.2 ± 12.8% vs. PMW: Δ2.2 ± 7.1%; p < 0.05 for group and condition). CCI decreased during Grip, Metabo, and CPT in YW and PMW, while the blockade prevented that decrease only in YW. The α1-adrenergic receptor plays a role in the control of coronary circulation in young women, evoking stronger vasoconstriction during CPT than Grip and Metabo in YW. PMW have impaired vasomotor control in the coronary circulation, which seems not to be caused by the α1-adrenergic receptor.

Expression profiles and functional analysis of tRNA-derived small RNAs in epicardial adipose tissue of patients with heart failure

BACKGROUND

Heart failure is considered an epidemic disease in the modern world. Since it presents as a multifactorial, systemic disease, a comprehensive understanding of the underlying mechanism is essential. Epicardial adipose tissue (EAT) is increasingly recognized to be metabolically active and is able to secrete myriad bioactive molecules, including exosomes carrying tRNA-derived small RNAs (tsRNAs). Mounting evidence has suggested that these specific tsRNAs dynamically impact fundamental cellular processes, but no studies have focused on the influence of tsRNA in EAT on cardiac dysfunction.

METHODS

To investigate the regulatory mechanism of tsRNAs of EAT associated with HF, we collected EAT from HF (n = 5) patients and controls (n = 5) and used a combination of RNA sequencing, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and bioinformatics to screen the expression profiles of tsRNAs in HF.

RESULTS

We ultimately identified an expression profile of 343 tsRNAs in EAT. Of those, a total of 24 tsRNAs were significantly differentially expressed between HF and controls: 17 were upregulated and 7 were downregulated (fold change >1.5, p < 0.05). Four tsRNAs (tiRNA-Pro-TGG-001, tRF-Met-CAT-002, tRF-Tyr-GTA-010 and tRF-Tyr-GTA-011) were randomly selected and validated by qRT-PCR. Bioinformatics analyses revealed a dense interaction of target genes between tRF-Tyr-GTA-010 and tRF-Tyr-GTA-011. Based on functional analysis, these two tRFs might play a protective role by regulating sphingolipid and adrenergic signaling pathways by targeting genes mainly contributing to calcium ion transport.

CONCLUSIONS

Our study profiled tsRNA expression in EAT with HF and identified a comprehensive dimension of potential target genes and tsRNA-mRNA interactions.

Circulating microRNA Profiles for Premature Cardiovascular Death in Patients with Kidney Failure with Replacement Therapy

INTRODUCTION

Patients with kidney failure with replacement therapy (KFRT) suffer from a disproportionately high cardiovascular disease burden. Circulating small non-coding RNAs (c-sncRNAs) have emerged as novel epigenetic regulators and are suggested as novel biomarkers and therapeutic targets for cardiovascular disease; however, little is known about the associations of c-sncRNAs with premature cardiovascular death in KFRT.

METHODS

In a pilot case-control study of 50 hemodialysis patients who died of cardiovascular events as cases, and 50 matched hemodialysis controls who remained alive during a median follow-up of 2.0 years, we performed c-sncRNAs profiles using next-generation sequencing to identify differentially expressed circulating microRNAs (c-miRNAs) between the plasma of cases and that of controls. mRNA target prediction and pathway enrichment analysis were performed to examine the functional relevance of differentially expressed c-miRNAs to cardiovascular pathophysiology. The association of differentially expressed c-miRNAs with cardiovascular mortality was examined using multivariable conditional logistic regression.

RESULTS

The patient characteristics were similar between cases and controls, with a mean age of 63 years, 48% male, and 54% African American in both groups. We detected a total of 613 miRNAs in the plasma, among which five miRNAs (i.e., miR-129-1-5p, miR-500b-3p, miR-125b-1-3p, miR-3648-2-5p, and miR-3150b-3p) were identified to be differentially expressed between cases and controls with cut-offs of p < 0.05 and log2 fold-change (log2FC) > 1. When using more stringent cut-offs of p-adjusted < 0.05 and log2FC > 1, only miR-129-1-5p remained significantly differentially expressed, with higher levels of miR-129-1-5p in the cases than in the controls. The pathway enrichment analysis using predicted miR-129-1-5p mRNA targets demonstrated enrichment in adrenergic signaling in cardiomyocytes, arrhythmogenic right ventricular cardiomyopathy, and oxytocin signaling pathways. In parallel, the circulating miR-129-1-5p levels were significantly associated with the risk of cardiovascular death (adjusted OR [95% CI], 1.68 [1.01-2.81] for one increase in log-transformed miR-129-1-5p counts), independent of potential confounders.

CONCLUSIONS

Circulating miR-129-1-5p may serve as a novel biomarker for premature cardiovascular death in KFRT.

Sirtuin 1 and Vascular Function in Healthy Women and Men: A Randomized Clinical Trial Comparing the Effects of Energy Restriction and Resveratrol

Background: Sirtuin 1 (SIRT1) has been associated with longevity and protection against cardiometabolic diseases, but little is known about how it influences human vascular function. Therefore, this study evaluated the effects of SIRT1 activation by resveratrol and energy restriction on vascular reactivity in adults. Methods: A randomized trial allocated 48 healthy adults (24 women and 24 men), aged 55 to 65 years, to resveratrol supplementation or energy restriction for 30 days. Blood lipids, glucose, insulin, C-reactive protein, noradrenaline, SIRT1 (circulating and gene expression), and flow-mediated vasodilation (FMD) and nitrate-mediated vasodilation (NMD) were measured. Results: Both interventions increased circulating SIRT1 (p < 0.001). Pre- and post-tests changes of plasma noradrenaline were significant for both groups (resveratrol: p = 0.037; energy restriction: p = 0.008). Baseline circulating SIRT1 was inversely correlated with noradrenaline (r = -0.508; p < 0.01), and post-treatment circulating SIRT1 was correlated with NMD (r = 0.433; p < 0.01). Circulating SIRT1 was a predictor of FMD in men (p = 0.045), but not in women. SIRT1 was an independent predictor of NMD (p = 0.026) only in the energy restriction group. Conclusions: Energy restriction and resveratrol increased circulating SIRT1 and reduced sympathetic activity similarly in healthy adults. SIRT1 was independently associated with NMD only in the energy restriction group.

5-HEPE reduces obesity and insulin resistance by promoting adipose tissue browning through GPR119/AMPK/PGC1α activation

AIMS

Activating thermogenic program in brown adipocytes serves as a potential therapeutic target for increasing energy expenditure during the treatment of metabolic diseases. 5(S)-hydroxy-eicosapentaenoic acid (5-HEPE), an omega-3 unsaturated fatty acid metabolite, has been shown to enhance insulin secretion in vitro. However, its role in modulating obesity-related diseases remains largely unclear.

MAIN METHODS

To investigate this further, mice were fed with a high-fat diet for 12 weeks and then injected intraperitoneally every other day with 5-HEPE for 4 additional weeks.

KEY FINDINGS

In vivo, our results demonstrated that 5-HEPE alleviated the HFD-induced obesity and insulin resistance, leading to a significant decrease in subcutaneous fat and epididymal fat index and an increase in brown fat index. Compared to the HFD group, the 5-HEPE group mice had lower ITT and GTT AUC and lower HOMA-IR. Moreover, 5HEPE effectively increased energy expenditure of mice. 5-HEPE also significantly promoted brown adipose tissue (BAT) activation and browning in white adipose tissue (WAT) by up-regulating genes and proteins expression of UCP1, Prdm16, Cidea, and PGC1α. In vitro, we found 5-HEPE significantly promoted 3T3-L1 browning. Mechanistically, 5-HEPE acts by activating the GPR119/AMPK/PGC1α pathway. In conclusion, this study emphasizes a critical role of 5-HEPE in improving body energy metabolism and adipose tissue browning in HFD-fed mice.

SIGNIFICANCE

Our results suggest that 5-HEPE intervention may be an effective target for preventing obesity-related metabolic diseases.

Vascular dysfunction in HFpEF: Potential role in the development, maintenance, and progression of the disease

Heart failure with preserved ejection fraction (HFpEF) is a complex, heterogeneous disease characterized by autonomic imbalance, cardiac remodeling, and diastolic dysfunction. One feature that has recently been linked to the pathology is the presence of macrovascular and microvascular dysfunction. Indeed, vascular dysfunction directly affects the functionality of cardiomyocytes, leading to decreased dilatation capacity and increased cell rigidity, which are the outcomes of the progressive decline in myocardial function. The presence of an inflammatory condition in HFpEF produced by an increase in proinflammatory molecules and activation of immune cells (i.e., chronic low-grade inflammation) has been proposed to play a pivotal role in vascular remodeling and endothelial cell death, which may ultimately lead to increased arterial elastance, decreased myocardium perfusion, and decreased oxygen supply to the tissue. Despite this, the precise mechanism linking low-grade inflammation to vascular alterations in the setting of HFpEF is not completely known. However, the enhanced sympathetic vasomotor tone in HFpEF, which may result from inflammatory activation of the sympathetic nervous system, could contribute to orchestrate vascular dysfunction in the setting of HFpEF due to the exquisite sympathetic innervation of both the macro and microvasculature. Accordingly, the present brief review aims to discuss the main mechanisms that may be involved in the macro- and microvascular function impairment in HFpEF and the potential role of the sympathetic nervous system in vascular dysfunction.

Efficacy of the New Inotropic Agent Istaroxime in Acute Heart Failure

Current therapeutic strategies for acute heart failure (AHF) are based on traditional inotropic agents that are often associated with untoward effects; therefore, finding new effective approaches with a safer profile is dramatically needed. Istaroxime is a novel compound, chemically unrelated to cardiac glycosides, that is currently being studied for the treatment of AHF. Its effects are essentially related to its inotropic and lusitropic positive properties exerted through a dual mechanism of action: activation of the sarcoplasmic reticulum Ca2+ ATPase isoform 2a (SERCA2a) and inhibition of the Na+/K+-ATPase (NKA) activity. The advantages of istaroxime over the available inotropic agents include its lower arrhythmogenic action combined with its capability of increasing systolic blood pressure without augmenting heart rate. However, it has a limited half-life (1 hour) and is associated with adverse effects including pain at the injection site and gastrointestinal issues. Herein, we describe the main mechanism of action of istaroxime and we present a systematic overview of both clinical and preclinical trials testing this drug, underlining the latest insights regarding its adoption in clinical practice for AHF.

Associations between β-Blocker Therapy at Discharge and Long-Term Follow-Up Outcomes in Patients with Unstable Angina Pectoris

Background

The effects of β-blockers in patients with unstable angina pectoris (UAP) are unclear. We tried to evaluate associations between β-blockers in UAP and long-term outcomes.

Methods

We enrolled 5591 UAP patients and divided them into 2 groups based on β-blockers at discharge: 3790 did β-blockers and 1801 did not used them. Propensity score matching at 1 : 1 was performed to select 1786 patients from each group. The primary endpoint was major adverse cardiac and cerebral events (MACCE) during the long-term follow-up period.

Results

67.8% of patients were on β-blockers at discharge; these patients were more likely to have CHD risk factors, lower ejection fraction, and severity of the coronary artery lesions. Over a median of 25.0 years, the incidence of MACCE was 25.5%. The risk was not significantly different between those on and those not on β-blocker treatment. The multivariate Cox regression analysis showed that no β-blocker use at discharge was not an independent risk factor for MACCE and sequence secondary endpoints. After propensity score matching, the results were similar.

Conclusions

β-blocker use was not associated with lower MACCE and other secondary composite endpoints in long-term outcomes. This result adds to the increasing body of evidence that the routine prescription of β-blockers might not be indicated in patients with UAP. Trial registration had retrospectively registered.

The Effects of Maternal Intake of EPA and DHA Enriched Diet During Pregnancy and Lactation on Offspring’s Muscle Development and Energy Homeostasis

EPA and DHA are n-3 long-chain polyunsaturated fatty acids with a diversity of health benefits on offspring. The objective of this study was to test the in vivo effect of maternal ingestion of EPA and DHA on fetal and offspring muscle development and energy balance. Two groups of female C57BL/6 mice were fed EPA and DHA enriched diet (FA) and diet devoid of EPA and DHA (CON) respectively throughout the entire period of gestation and lactation. Embryos at E13 and offspring at age of D1 and D21 were selected for sample collection and processing. No change in birth number and body weight were observed between groups at D1 and D21. Transient increase in the expression levels of myogenesis regulating genes was detected at D1 (p < 0.05) in FA group. Most of the expression of muscle protein synthesis regulating genes were comparable (p > 0.05) between FA and CON groups at D1 and D21. The significant increase in MHC4, and IGF-1 was not linked to increased muscle mass. A persistent increase in ISR expression (p < 0.05) but not in GLUT-4 (p > 0.05) was detected in offspring. Up-regulation of adipogenesis regulating genes was accompanied by increasing intramuscular fat accumulation in the offspring of FA group. Considerable increase in transcripts of genes regulating lipid catabolism and thermogenesis in liver (p < 0.05) was noticed in FA group at D21; whereas, only the levels of carnitine palmitoyl transferase 1A (Cpt1α) and Enoyl-CoA Hydratase And 3-Hydroxyacyl CoA Dehydrogenase (Ehhadh) increased at D1. Similarly, genes regulating lipolysis were highly expressed at D21 in FA group. EPA and DHA treatment promoted BAT development and activity by increasing the expression of BAT signature genes (p < 0.05). Also, maternal intake of EPA and DHA enriched diet enhanced browning of sWAT. Taken together, maternal ingestion of EPA/DHA may be suggested as a therapeutic option to improve body composition and counteract childhood obesity- related metabolic disorders and confer lifelong positive metabolic impact on offspring.

Beta-Blocker Use in Older Hospitalized Patients Affected by Heart Failure and Chronic Obstructive Pulmonary Disease: An Italian Survey From the REPOSI Register

Beta (β)-blockers (BB) are useful in reducing morbidity and mortality in patients with heart failure (HF) and concomitant chronic obstructive pulmonary disease (COPD). Nevertheless, the use of BBs could induce bronchoconstriction due to β2-blockade. For this reason, both the ESC and GOLD guidelines strongly suggest the use of selective β1-BB in patients with HF and COPD. However, low adherence to guidelines was observed in multiple clinical settings. The aim of the study was to investigate the BBs use in older patients affected by HF and COPD, recorded in the REPOSI register. Of 942 patients affected by HF, 47.1% were treated with BBs. The use of BBs was significantly lower in patients with HF and COPD than in patients affected by HF alone, both at admission and at discharge (admission, 36.9% vs. 51.3%; discharge, 38.0% vs. 51.7%). In addition, no further BB users were found at discharge. The probability to being treated with a BB was significantly lower in patients with HF also affected by COPD (adj. OR, 95% CI: 0.50, 0.37–0.67), while the diagnosis of COPD was not associated with the choice of selective β1-BB (adj. OR, 95% CI: 1.33, 0.76–2.34). Despite clear recommendations by clinical guidelines, a significant underuse of BBs was also observed after hospital discharge. In COPD affected patients, physicians unreasonably reject BBs use, rather than choosing a β1-BB. The expected improvement of the BB prescriptions after hospitalization was not observed. A multidisciplinary approach among hospital physicians, general practitioners, and pharmacologists should be carried out for better drug management and adherence to guideline recommendations.

Cardiac Remodeling in Hypertension: Clinical Impact on Brain, Heart, and Kidney Function

Hypertension is the most common causative factor of cardiac remodeling, which, in turn, has been associated with changes in brain and kidney function. Currently, the role of blood biomarkers as indices of cardiac remodeling remains unclear. In contrast, cardiac imaging, including echocardiography and cardiovascular magnetic resonance (CMR), has been a valuable noninvasive tool to assess cardiac remodeling. Cardiac remodeling during the course of systemic hypertension is not the sole effect of the latter. "Remodeling" of other vital organs, such as brain and kidney, also takes place. Therefore, it will be more accurate if we discuss about "hypertensive remodeling" involving the heart, the brain, and the kidneys, rather than isolated cardiac remodeling. This supports the idea of their simultaneous assessment to identify the early, silent lesions of total "hypertensive remodeling". In this context, magnetic resonance imaging is the ideal modality to provide useful information about these organs in a noninvasive fashion and without radiation. For this purpose, we propose a combined protocol to employ MRI in the simultaneous assessment of the heart, brain and kidneys. This protocol should include all necessary indices for the evaluation of "hypertensive remodeling" in these 3 organs, and could be performed within a reasonable time, not exceeding one hour, so that it remains patient-friendly. Furthermore, a combined protocol may offer "all in one examination" and save time. Finally, the amount of contrast agent used will be limited granted that post-contrast evaluations of the three organs will be performed after 1 injection.

IP3 receptor orchestrates maladaptive vascular responses in heart failure

Patients with heart failure (HF) have augmented vascular tone, which increases cardiac workload, impairing ventricular output and promoting further myocardial dysfunction. The molecular mechanisms underlying the maladaptive vascular responses observed in HF are not fully understood. Vascular smooth muscle cells (VSMCs) control vasoconstriction via a Ca²⁺-dependent process, in which the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) on the sarcoplasmic reticulum (SR) plays a major role. To dissect the mechanistic contribution of intracellular Ca²⁺ release to the increased vascular tone observed in HF, we analyzed the remodeling of IP3R1 in aortic tissues from patients with HF and from controls. VSMC IP3R1 channels from patients with HF and HF mice were hyperphosphorylated by both serine and tyrosine kinases. VSMCs isolated from IP3R1^VSMC–/– mice exhibited blunted Ca²⁺ responses to angiotensin II (ATII) and norepinephrine compared with control VSMCs. IP3R1^VSMC–/– mice displayed significantly reduced responses to ATII, both in vivo and ex vivo. HF IP3R^1VSMC–/– mice developed significantly less afterload compared with HF IP3R1^fl/fl mice and exhibited significantly attenuated progression toward decompensated HF and reduced interstitial fibrosis. Ca²⁺-dependent phosphorylation of the MLC by MLCK activated VSMC contraction. MLC phosphorylation was markedly increased in VSMCs from patients with HF and HF mice but reduced in VSMCs from HF IP3R1^VSMC–/– mice and HF WT mice treated with ML-7. Taken together, our data indicate that VSMC IP3R1 is a major effector of increased vascular tone, which contributes to increased cardiac afterload and decompensation in HF.

Effects of Sodium Ferulate on Cardiac Hypertrophy Are via the CaSR-Mediated Signaling Pathway

As a common complication of many cardiovascular diseases, cardiac hypertrophy is characterized by increased cardiac cell volume, reorganization of the cytoskeleton, and the reactivation of fetal genes such as cardiac natriuretic peptide and β-myosin heavy chain. Cardiac hypertrophy is a distinguishing feature of some cardiovascular diseases. Our previous study showed that sodium ferulate (SF) alleviates myocardial hypertrophy induced by coarctation of the abdominal aorta, and these protective effects may be related to the inhibition of protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) signaling pathways. This study investigated the inhibitory effect and mechanism of SF on myocardial hypertrophy in spontaneously hypertensive rats (SHRs). The effects of SF on cardiac hypertrophy were evaluated using echocardiographic measurement, pathological analysis, and detection of atrial natriuretic peptide (ANP) and β-myosin heavy chain (β-MHC) expression. To investigate the mechanisms underlying the anti-hypertrophic effects of SF, the calcium-sensing receptor (CaSR), calcineurin (CaN), nuclear factor of activated T cells 3 (NFAT3), zinc finger transcription factor 4 (GATA4), protein kinase C beta (PKC-β), Raf-1, extracellular signal-regulated kinase 1/2 (ERK 1/2), and mitogen-activated protein kinase phosphatase-1 (MKP-1) were detected by molecular biology techniques. Treatment with SF ameliorated myocardial hypertrophy in 26-week-old SHRs. In addition, it downregulated the levels of ANP, β-MHC, CaSR, CaN, NFAT3, phosphorylated GATA4 (p-GATA4), PKC-β, Raf-1, and p-ERK 1/2; and upregulated the levels of p-NFAT3 and MKP-1. These results suggest that the effects of SF on cardiac hypertrophy are related to regulation of the CaSR-mediated signaling pathway.

Comparison of Resveratrol Supplementation and Energy Restriction Effects on Sympathetic Nervous System Activity and Vascular Reactivity: A Randomized Clinical Trial

Background: Chronic sympathetic nervous system activation is associated with endothelial dysfunction and cardiometabolic disease, which may be modulated by resveratrol (RSV) and energy restriction (ER). This study aimed to examine the effects of RSV and ER on plasma noradrenaline (NA), flow-mediated vasodilation (ed-FMD), and endothelium-independent nitrate-mediated vasodilation (ei-NMD). Methods: The study included 48 healthy adults randomized to 30-days intervention of RSV or ER. Results: Waist circumference, total cholesterol, HDL-c, LDL-c, apoA-I, and plasma NA decreased in the ER group, whilst RSV increased apoB and total cholesterol, without changing plasma NA. No effects on vascular reactivity were observed in both groups. Plasma NA change was positively correlated with total cholesterol (r = 0.443; p = 0.002), triglycerides (r = 0.438; p = 0.002), apoA-I (r = 0.467; p = 0.001), apoB (r = 0.318; p = 0.032) changes, and ei-NMD (OR = 1.294; 95%CI: 1.021–1.640). Conclusions: RSV does not improve cardiometabolic risk factors, sympathetic activity, and endothelial function. ER decreases plasma NA and waist circumference as well as improves blood lipids, but does not modify endothelial function. Finally, plasma NA was associated with ei-NMD, which could be attributed to a higher response to nitrate in patients with greater resting sympathetic vasoconstriction.

Inflammation as a Possible Trigger for Mitoxantrone-Induced Cardiotoxicity: An In Vivo Study in Adult and Infant Mice

Mitoxantrone (MTX) is a pharmaceutical drug used in the treatment of several cancers and refractory multiple sclerosis (MS). Despite its therapeutic value, adverse effects may be severe, namely the frequently reported cardiotoxicity, whose mechanisms need further research. This work aimed to assess if inflammation or oxidative stress-related pathways participate in the cardiotoxicity of MTX, using the mouse as an animal model, at two different age periods (infant or adult mice) using two therapeutic relevant cumulative doses. Histopathology findings showed that MTX caused higher cardiac toxicity in adults. In MTX-treated adults, at the highest dose, noradrenaline cardiac levels decreased, whereas at the lowest cumulative dose, protein carbonylation increased and the expression of nuclear factor kappa B (NF-κB) p65 subunit and of M1 macrophage marker increased. Moreover, MTX-treated adult mice had enhanced expression of NF-κB p52 and tumour necrosis factor (TNF-α), while decreasing interleukin-6 (IL-6). Moreover, while catalase expression significantly increased in both adult and infant mice treated with the lowest MTX cumulative dose, the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glutathione peroxidase only significantly increased in infant animals. Nevertheless, the ratio of GAPDH to ATP synthase subunit beta decreased in adult animals. In conclusion, clinically relevant doses of MTX caused dissimilar responses in adult and infant mice, being that inflammation may be an important trigger to MTX-induced cardiotoxicity.

Anderson-Fabry Disease: From Endothelial Dysfunction to Emerging Therapies

The Anderson–Fabry disease is a rare, X-linked, multisystemic, progressive lysosomal storage disease caused by α-galactosidase A total or partial deficiency. The resulting syndrome is mainly characterized by early-onset autonomic neuropathy and life-threatening multiorgan involvement, including renal insufficiency, heart disease, and early stroke. The enzyme deficiency leads to tissue accumulation of the glycosphingolipid globotriaosylceramide and its analogues, but the mechanisms linking such accumulation to organ damage are only partially understood. In contrast, enzyme replacement and chaperone therapies are already fully available to patients and allow substantial amelioration of quality and quantity of life. Substrate reduction, messenger ribonucleic acid (mRNA)-based, and gene therapies are also on the horizon. In this review, the clinical scenario and molecular aspects of Anderson–Fabry disease are described, along with updates on disease mechanisms and emerging therapies.

The GRKs Reactome: Role in Cell Biology and Pathology

G protein-coupled receptor kinases (GRKs) are protein kinases that function in concert with arrestins in the regulation of a diverse class of G protein-coupled receptors (GPCRs) signaling. Although GRKs and arrestins are key participants in the regulation of GPCR cascades, the complex regulatory mechanisms of GRK expression, its alternation, and their function are not thoroughly understood. Several studies together with the work from our lab in recent years have revealed the critical role of these kinases in various physiological and pathophysiological processes, including cardiovascular biology, inflammation and immunity, neurodegeneration, thrombosis, and hemostasis. A comprehensive understanding of the mechanisms underlying functional interactions with multiple receptor proteins and how these interactions take part in the development of various pathobiological processes may give rise to novel diagnostic and therapeutic strategies. In this review, we summarize the current research linking the role of GRKs to various aspects of cell biology, pathology, and therapeutics, with a particular focus on thrombosis and hemostasis.

β-Adrenergic receptor, an essential target in cardiovascular diseases

β-Adrenergic receptors (βARs) belong to a large family of cell surface receptors known as G protein-coupled receptors (GPCRs). They are coupled to Gs protein (Gαs) for the activation of adenylyl cyclase (AC) yielding cyclic AMP (_CAMP), and this provides valuable responses, which can affect the cardiac function such as injury. The binding of an agonist to βAR enhances conformation changes that lead to the Gαs subtype of heterotrimeric G protein which is the AC stimulatory G protein for activation of _CAMP in the cells. However, cardiovascular diseases (CVD) have been reported as having an increased rate of death and β1AR, and β2AR are a promising tool that improves the regulatory function in the cardiovascular system (CVS) via signaling. It increases the Gα level, which activates βAR kinase (βARK) that affects and enhances the progression of heart failure (HF) through the activation of cardiomyocyte βARs. We also explained that an increase in GPCR kinases (GRKs) would practically improve the HF pathogenesis and this occurs via the desensitization of βARs, which causes the loss of contractile reserve. The consistency or overstimulation of catecholamines contributes to CVD such as stroke, HF, and cardiac hypertrophy. When there is a decrease in catecholamine responsiveness, it causes aging in old people because the reduction of βAR sensitivity and density in the myocardium enhances downregulation of βARs to AC in the human heart.

Monoamine oxidases in age-associated diseases: New perspectives for old enzymes

Population aging is one of the most significant social changes of the twenty-first century. This increase in longevity is associated with a higher prevalence of chronic diseases, further rising healthcare costs. At the molecular level, cellular senescence has been identified as a major process in age-associated diseases, as accumulation of senescent cells with aging leads to progressive organ dysfunction. Of particular importance, mitochondrial oxidative stress and consequent organelle alterations have been pointed out as key players in the aging process, by both inducing and maintaining cellular senescence. Monoamine oxidases (MAOs), a class of enzymes that catalyze the degradation of catecholamines and biogenic amines, have been increasingly recognized as major producers of mitochondrial ROS. Although well-known in the brain, evidence showing that MAOs are also expressed in a variety of peripheral organs stimulated a growing interest in the extra-cerebral roles of these enzymes. Besides, the fact that MAO-A and/or MAO-B are frequently upregulated in aged or dysfunctional organs has uncovered new perspectives on their roles in pathological aging. In this review, we will give an overview of the major results on the regulation and function of MAOs in aging and age-related diseases, paying a special attention to the mechanisms linked to the increased degradation of MAO substrates or related to MAO-dependent ROS formation.

Compartmentalized Signaling in Aging and Neurodegeneration

The cyclic AMP (cAMP) signalling cascade is necessary for cell homeostasis and plays important roles in many processes. This is particularly relevant during ageing and age-related diseases, where drastic changes, generally decreases, in cAMP levels have been associated with the progressive decline in overall cell function and, eventually, the loss of cellular integrity. The functional relevance of reduced cAMP is clearly supported by the finding that increases in cAMP levels can reverse some of the effects of ageing. Nevertheless, despite these observations, the molecular mechanisms underlying the dysregulation of cAMP signalling in ageing are not well understood. Compartmentalization is widely accepted as the modality through which cAMP achieves its functional specificity; therefore, it is important to understand whether and how this mechanism is affected during ageing and to define which is its contribution to this process. Several animal models demonstrate the importance of specific cAMP signalling components in ageing, however, how age-related changes in each of these elements affect the compartmentalization of the cAMP pathway is largely unknown. In this review, we explore the connection of single components of the cAMP signalling cascade to ageing and age-related diseases whilst elaborating the literature in the context of cAMP signalling compartmentalization.

Why Do We Not Assess Sympathetic Nervous System Activity in Heart Failure Management: Might GRK2 Serve as a New Biomarker?

Heart failure (HF) represents the end-stage condition of several structural and functional cardiovascular diseases, characterized by reduced myocardial pump function and increased pressure load. The dysregulation of neurohormonal systems, especially the hyperactivity of the cardiac adrenergic nervous system (ANS), constitutes a hallmark of HF and exerts a pivotal role in its progression. Indeed, it negatively affects patients’ prognosis, being associated with high morbidity and mortality rates, with a tremendous burden on global healthcare systems. To date, all the techniques proposed to assess the cardiac sympathetic nervous system are burdened by intrinsic limits that hinder their implementation in clinical practice. Several biomarkers related to ANS activity, which may potentially support the clinical management of such a complex syndrome, are slow to be implemented in the routine practice for several limitations due to their assessment and clinical impact. Lymphocyte G-protein-coupled Receptor Kinase 2 (GRK2) levels reflect myocardial β-adrenergic receptor function in HF and have been shown to add independent prognostic information related to ANS overdrive. In the present manuscript, we provide an overview of the techniques currently available to evaluate cardiac ANS in HF and future perspectives in this field of relevant scientific and clinical interest.

Integrated network pharmacology and molecular docking approaches to reveal the synergistic mechanism of multiple components in Venenum Bufonis for ameliorating heart failure

Venenum Bufonis (VB), also called Chan Su in China, has been extensively used as a traditional Chinese medicine (TCM) for treating heart failure (HF) since ancient time. However, the active components and the potential anti-HF mechanism of VB remain unclear. In the current study, the major absorbed components and metabolites of VB after oral administration in rats were first collected from literatures. A total of 17 prototypes and 25 metabolites were gathered. Next, a feasible network-based pharmacological approach was developed and employed to explore the therapeutic mechanism of VB on HF based on the collected constituents. In total, 158 main targets were screened out and considered as effective players in ameliorating HF. Then, the VB components-main HF putative targets-main pathways network was established, clarifying the underlying biological process of VB on HF. More importantly, the main hubs were found to be highly enriched in adrenergic signalling in cardio-myocytes. After verified by molecular docking studies, four key targets (ATP1A1, GNAS, MAPK1 and PRKCA) and three potential active leading compounds (bufotalin, cinobufaginol and 19-oxo-bufalin) were identified, which may play critical roles in cardiac muscle contraction. This study demonstrated that the integrated strategy based on network pharmacology and molecular docking was helpful to uncover the synergistic mechanism of multiple constituents in TCM.

CLOCK-BMAL1 regulates circadian oscillation of ventricular arrhythmias in failing hearts through β1 adrenergic receptor

The incidence of ventricular arrhythmias (VAs) in chronic heart failure (CHF) exhibits a notable circadian rhythm, for which the underlying mechanism has not yet been well defined. Thus, we aimed to investigate the role of cardiac core circadian genes on circadian VAs in CHF. First, a guinea pig CHF model was created by transaortic constriction. Circadian oscillation of core clock genes was evaluated by RT-PCR and was found to be unaltered in CHF (P > 0.05). Using programmed electrical stimulation in Langendorff-perfused failing hearts, we discovered that the CHF group exhibited increased VAs with greater incidence at CT3 compared to CT15 upon isoproterenol (ISO) stimulation. Circadian VAs was blunted by a β1-AR-selective blocker rather than a β2-AR-selective blocker. Circadian oscillation of β1-AR was retained in CHF (P > 0.05) and a 4-h phase delay between β1-AR and CLOCK-BMAL1 was recorded. Therefore, when CLOCK-BMAL1 was overexpressed using adenovirus infection, an induced overexpression of β1-AR also ensued, which resulted in prolonged action potential duration (APD) and enhanced arrhythmic response to ISO stimulation in cardiomyocytes (P < 0.05). Finally, chromatin immunoprecipitation and luciferase assays confirmed that CLOCK-BMAL1 binds to the enhancer of β1-AR gene and upregulates β1-AR expression. Therefore, in this study, we discovered that CLOCK-BMAL1 regulates the expression of β1-AR on a transcriptional level and subsequently modulates circadian VAs in CHF.

Cardiovascular Alterations and Management of Patients With White Coat Hypertension: A Meta-Analysis

A large and growing body of literature has focused on the association between "white coat hypertension" (WCH) and the underlying target organ damage. The evidence suggests that WCH is may not an entirely benign phenomenon. However, whether patients with WCH should receive antihypertensive drugs is unresolved. Therefore, we performed a meta-analysis to fully determine the ability of WCH to alter cardiovascular structure and to determine whether patients with WCH could benefit from drug intervention. Medline, EMBASE, and the Cochrane Library were searched from inception through 21 Oct 2019. A total of 25 studies (8,100 individuals) were included. In participants with WCH, values of aortic pulse wave velocity, augmentation index, intima-media thickness, interventricular septum thickness, left ventricular posterior wall thickness, and left ventricular mass index were lower than those with sustained hypertension, but greater than those in the normotensive group. Of note, antihypertensive drug therapy did not reduce the risk of cardiovascular events in patients with WCH. WCH is accompanied by alterations of cardiovascular structure; however, the benefits from antihypertensive therapy are limited.

Gaining insight into cellular cardiac physiology using single particle tracking

Single particle tracking (SPT) is a robust technique to monitor single-molecule behaviors in living cells directly. By this approach, we can uncover the potential biological significance of particle dynamics by statistically characterizing individual molecular behaviors. SPT provides valuable information at the single-molecule level, that could be obscured by simple averaging that is inherent to conventional ensemble measurements. Here, we give a brief introduction to SPT including the commonly used optical implementations, fluorescence labeling strategies, and data analysis methods. We then focus on how SPT has been harnessed to decipher myocardial function. In this context, SPT has provided novel insight into the lateral diffusion of signal receptors and ion channels, the dynamic organization of cardiac nanodomains, subunit composition and stoichiometry of cardiac ion channels, myosin movement along actin filaments, the kinetic features of transcription factors involved in cardiac remodeling, and the intercellular communication by nanotubes. Finally, we speculate on the prospects and challenges of applying SPT to future questions regarding cellular cardiac physiology using SPT.

Investigating Anti-Obesity Effects by Oral Administration of Aloe vera Gel Extract (AVGE): Possible Involvement in Activation of Brown Adipose Tissue (BAT)

The aim of this study is to investigate the mechanism of anti-obesity effects of Aloe vera gel extract (AVGE) containing Aloe sterols. Previously, we reported that oral intake of Aloe vera components has an anti-diabetic and anti-obesity effect. This study was designed to assess the role of brown adipose tissue (BAT) in the anti-obesity effect of AVGE. Six-week-old male mice were divided into three groups; STD (standard diet), HFD (60% high fat diet) and AVGE (60% high fat diet with AVGE treatment). During 11 wk of AVGE administration, body weight has been monitored. Tissue samples were obtained to be measured the weight and evaluated the gene expressions. Mice treated with AVGE had suppressed body weight, and liver and fat weight gain. To investigate BAT activation, we measured the expression of mRNA related to BAT thermogenesis. Mice in the AVGE group had higher expression of Ucp1, Adrb3, and Cidea in BAT compared to HFD. Next, to investigate the possibility that AVGE induced hepatic FGF21, which is an important factor for nutrient and energy homeostasis including BAT regulation, in vitro study was conducted. HepG2 cell stimulated by AVGE were highly expressed FGF21. These results suggested that BAT activation partially contributes to mechanism of anti-obesity effect of Aloe sterols in diet-induced obesity (DIO) models. However, further study is needed to determine the predominant mechanism.

Effects of β2-receptor stimulation by indacaterol in chronic heart failure treated with selective or non-selective β-blockers: a randomized trial

Alveolar β₂-receptor blockade worsens lung diffusion in heart failure (HF). This effect could be mitigated by stimulating alveolar β₂-receptors. We investigated the safety and the effects of indacaterol on lung diffusion, lung mechanics, sleep respiratory behavior, cardiac rhythm, welfare, and exercise performance in HF patients treated with a selective (bisoprolol) or a non-selective (carvedilol) β-blocker. Study procedures were performed before and after indacaterol and placebo treatments according to a cross-over, randomized, double-blind protocol in forty-four patients (27 on bisoprolol and 17 on carvedilol). No differences between indacaterol and placebo were observed in the whole population except for a significantly higher VE/VCO₂ slope and lower maximal P_ETCO₂ during exercise with indacaterol, entirely due to the difference in the bisoprolol group (VE/VCO₂ 31.8 ± 5.9 vs. 28.5 ± 5.6, p < 0.0001 and maximal P_ETCO₂ 36.7 ± 5.5 vs. 37.7 ± 5.8 mmHg, p < 0.02 with indacaterol and placebo, respectively). In carvedilol, indacaterol was associated with a higher peak heart rate (119 ± 34 vs. 113 ± 30 bpm, with indacaterol and placebo) and a lower prevalence of hypopnea during sleep (3.8 [0.0;6.3] vs. 5.8 [2.9;10.5] events/hour, with indacaterol and placebo). Inhaled indacaterol is well tolerated in HF patients, it does not influence lung diffusion, and, in bisoprolol, it increases ventilation response to exercise.

Increased pulmonary blood volume variation in patients with heart failure compared to healthy controls: a noninvasive, quantitative measure of heart failure

Variation of the blood content of the pulmonary vascular bed during a heartbeat can be quantified by pulmonary blood volume variation (PBVV) using magnetic resonance imaging (MRI). The aim was to evaluate whether PBVV differs in patients with heart failure compared with healthy controls and investigate the mechanisms behind the PBVV. Forty-six patients and 10 controls underwent MRI. PBVV was calculated from blood flow measurements in the main pulmonary artery and a pulmonary vein, defined as the maximum difference in cumulative PBV over one heartbeat. PBVV was indexed to stroke volume (SV) in the main pulmonary artery (PBVV_SV). Patients displayed higher PBVV_SV than controls (58 ± 14 vs. 43 ± 7%, P < 0.001). The change in PBVV_SV could be explained by left ventricular (LV) longitudinal contribution to SV (R² = 0.15, P = 0.02) and the phase shift between in- and outflow (R² = 0.31, P < 0.001) in patients. Both variables contributed to the multiple regression analysis model and predicted PBVV_SV (R² = 0.38); however, the phase shift alone explained ~30% of the variation in PBVV_SV. No correlation was found between PBVV_SV and large vessel area. In conclusion, PBVV_SV was higher in patients compared with controls. Approximately 40% of the variation of PBVV_SV in patients can be explained by the LV longitudinal contribution to SV and the phase shift between pulmonary in- and outflow, where the phase shift alone accounts for ~30%. The remaining variation (60-70%) most likely occurs on a small vessel level. Future studies are needed to show the clinical added value of PBVV_SV compared with right-heart catheterization.NEW & NOTEWORTHY This study shows that the pulmonary blood volume variation indexed to the stroke volume is higher in patients with heart failure compared with controls. The mechanisms behind this are lack of systolic suction from the left ventricular atrioventricular plane descent and increased phase shift between the in- and outflow to the pulmonary circulation (~40%), where the phase shift alone accounts for ~30%. The remaining variation (60-70%) is suggested to occur on a small vessel level.

Blockade of β-adrenergic signaling suppresses inflammasome and alleviates cardiac fibrosis

Background

Heart failure (HF) is an end-stage syndrome of all structural heart diseases which accompanies the loss of myocardium and cardiac fibrosis. Although the role of inflammasome in cardiac fibrosis has recently been a point of focus, the mechanism of inflammasome activation in HF has not yet been elucidated.

Methods

In this study, we investigated the expression of inflammasome proteins in a rat thoracic aorta constriction (TAC) model and cultured cardiac fibroblasts with stimulation of norepinephrine (NE).

Results

Our results showed that levels of inflammasome proteins in the myocardial of TAC rats were elevated. By blocking β-adrenergic signaling in the rats, inflammasome activation was suppressed and heart function was improved. The stimulation of cultured cardiac fibroblasts with NE activated inflammasome in vitro, which was abrogated by the inhibition of the calcium channels and reactive oxygen species (ROS). The activation of inflammasome by NE promoted cardiac fibrosis, whereas the inhibition of the calcium channels, ROS, and inflammasome reduced this effect.

Conclusions

The present study indicated that activation of inflammasome by β-adrenergic signaling promotes cardiac fibrosis. Therefore, modulation of inflammasome during HF might provide a novel strategy to treat this disease.

Sustained GRK2-dependent CREB activation is essential for α2-adrenergic receptor-induced PC12 neuronal differentiation

Many aspects of neuronal development, such as neuronal survival and differentiation, are regulated by the transcription factor cAMP-response element-binding protein (CREB). We have previously reported that α₂-adrenergic receptors (ARs), members of the G protein-coupled receptor (GPCR) superfamily, induce neuronal differentiation of rat pheochromocytoma (PC)-12 cells in a subtype-specific manner, i.e. α_2A<α_2B<α_2C. Herein, we sought to investigate CREB`s involvement in this α<sub>2</sub>AR-dependent neurogenic process. We used a combination of gene reporter assays and immunoblotting analysis, coupled with co-immunoprecipitation and morphological analysis, in transfected PC12 cell lines. Chronic α<sub>2B</sub>- or α<sub>2C</sub>-AR activation results in sustained CREB activation, which is both necessary and sufficient for neuronal differentiation of PC12 cells expressing these two α<sub>2</sub>ARs. In contrast, chronic α<sub>2A</sub> activation only leads to transient CREB activation, insufficient for PC12 neuronal differentiation. However, upon CREB overexpression, α<sub>2A</sub>-AR triggers neuronal differentiation similarly to α<sub>2B</sub>- or α<sub>2C</sub>-ARs. Importantly, NGF (Nerve Growth Factor)`s TrkA receptor transactivation is essential for the sustained activation of CREB by all three α₂ subtypes in PC12 cells, whereas protein kinase A (PKA), the prototypic kinase that phosphorylates CREB, is not. Instead, TrkA-activated GPCR-kinase (GRK)-2 mediates the sustained CREB activation during α₂AR-induced neuronal differentiation of PC12 cells. In conclusion, catecholaminergic-induced neuronal differentiation of PC12 cells through α₂ARs uses a non-canonical pathway involving TrkA transactivation and subsequent GRK2-dependent, sustained phosphorylation/activation of CREB. These findings provide novel insights into catecholaminergic neurogenesis and suggest that α₂AR agonists, combined with NGF analogs or GRK2 stimulators, may exert neurogenic/neuroprotective effects.

The role of interleukin-6 in intracellular signal transduction after chronic β-adrenergic stimulation in mouse myocardium

INTRODUCTION

Inflammatory mediators play an important role in development and progression of cardiovascular disease. Both adrenergic stimulation and high levels of interleukin-6 (IL-6) indicate an unfavorable outcome in patients with myocardial infarction or heart failure. Understanding the interaction between β-adrenergic stimulation and IL-6 in the myocardium may contribute to developing more effective treatments. The aim of this study was to verify the role of IL-6 in the effects of β-adrenergic stimulation in activating selected intracellular signaling pathways in mouse myocardium.

MATERIAL AND METHODS

Experiments were performed on 12-week-old male mice: 16 C57BL/6JIL6^{‑/‑TMKopf} (IL-6 KO) and 17 C57BL/6J (WT). Animals received intraperitoneal injections of isoproterenol (ISO, 50 mg/kg) or placebo (0.9% NaCl) once a day for 16 days. The phosphorylation of STAT3 (signal transducer and activator of transcription 3), ERK1/2 (extracellular-regulated kinases 1/2), Akt1/2/3, p-38, c-Raf and expression of SOCS3 (suppressor of cytokine signaling 3), PIAS1/3 (protein inhibitors of activated STAT) was assessed by western blotting in the myocardium 24 h after the last injection. Evaluation of gene expression downstream of these pathways was performed by real-time PCR.

RESULTS

Chronic ISO treatment leads to increased fibrosis of the myocardium in mice lacking IL-6, which is accompanied by increased activity of ERK1/2, p38 and reduced expression of SOCS3. Administration of ISO in IL-6 KO animals intensified gene expression of proteins activated by MAPK/ERK (myc; CEBPB; BMP4; Fasn; Tank), while it reduced expression of genes repressed by ERK 1/2 (Wisp1, Wnt1).

CONCLUSIONS

IL-6 plays an important role in regulating the activation of MAPK pathways in the mouse myocardium in response to chronic β-adrenergic stimulation.

Beta-blocker choice and exchangeability in patients with heart failure and chronic obstructive pulmonary disease: an Italian register-based cohort study

Clinical guidelines suggest that for patients with heart failure and concurrent chronic obstructive pulmonary disease (COPD), metoprolol/bisoprolol/nebivolol should be preferred over carvedilol. However, studies suggest a high proportion of carvedilol usage that remains unexplained. Therefore, we aimed to investigate the predictors of carvedilol choice in patients with heart failure and COPD that were naïve to carvedilol or metoprolol/bisoprolol/nebivolol. Caserta Local Health Unit databases (Italy) were used as data sources. Age, sex, chronic/acute comorbidities, and co-medications were included in a logistic regression model to assess predictors of carvedilol choice. Chronic comorbidities include those defined in the Elixhauser comorbidity index and all hospitalizations within two years prior to the first beta-blocker prescription. Comedications include all redeemed prescriptions within one year prior to the beta-blocker prescription. Kernel density estimations were used to assess the overlap in propensity and preference scores distributions for receiving carvedilol and thereby potential beta-blocker exchangeability. Totally, 10091 patients composed the study population; 2011 were exposed to carvedilol. The overlapping of propensity scores distributions was 57%. Accordingly, the exchangeability was not reached. Atrioventricular block (Odds Ratio, OR 8.20; 95% Confidence Interval, 95% CI 1.30–51.80), cerebrovascular thrombosis (OR 7.06; 95% CI 1.14–43.68), chronic kidney disease (OR 4.32; 95% CI 1.16–16.02), and acute heart failure (OR 1.97; 95% CI 1.28–3.03) hospitalizations were statistically significantly associated with carvedilol choice. Analogously, human insulin (OR 3.00; 95% CI 1.24–7.24), fondaparinux (OR 2.47; 95% CI 1.17–5.21) or strontium ranelate (OR 2.03; 95% CI 1.06–3.90) redeemed prescriptions. In conclusion, this study suggests the absence of beta-blockers exchangeability and a preferential choice of carvedilol in patients with heart failure, COPD and concurrent chronic kidney disease, atrioventricular block, cerebrovascular thrombosis, acute heart failure or redeeming human insulin, fondaparinux or strontium ranelate prescriptions. Therefore, it suggests that choice of prescribing carvedilol over metoprolol/bisoprolol/nebivolol is driven by differences in comorbidities and co-treatments.

Differential mechanisms of action of the trace amines octopamine, synephrine and tyramine on the porcine coronary and mesenteric artery

Trace amines such as p-tyramine, p-octopamine and p-synephrine are found in low concentrations in animals and plants. Consumption of pre-workout supplements containing these plant-derived amines has been associated with cardiovascular side effects. The aim of this study was to determine the mechanisms of action of these trace amines on porcine isolated coronary and mesenteric arteries. Noradrenaline caused contraction of mesenteric arteries and relaxation of coronary arteries. In both tissues, all three trace amines induced contractions with similar potencies and responses were unaffected by the β-adrenoceptor antagonist propranolol (1 µM), the nitric oxide synthase inhibitor L-NNA (100 µM), or the TAAR-1 antagonist, EPPTB (100 nM). However, the contractile responses of mesenteric arteries, but not coronary arteries, were significantly reduced by depletion of endogenous noradrenaline. Mesenteric responses to all three amines were abolished in the presence of prazosin (1 µM) whereas residual contractile responses remained in the coronary artery which were inhibited by a high concentration (100 µM) of EPPTB. The results suggest complex responses of the coronary artery to the trace amines, with activity at α₁-adrenoceptors and potentially TAARs other than TAAR-1. In contrast the actions of the amines on the mesenteric artery appeared to involve indirect sympathomimetic actions and direct actions on α₁-adrenoceptors.

Association of Prehospital Epinephrine Administration With Survival Among Patients With Traumatic Cardiac Arrest Caused By Traffic Collisions

For traumatic cardiac arrest (TCA), the effect of prehospital epinephrine administration was unclear. The aim of this study was to evaluate the relationship between prehospital epinephrine administration and survival in patients with TCA caused by traffic collisions. We conducted a nationwide, prospective, population-based observational study involving patients who experienced out-of-hospital cardiac arrest (OHCA) by using the All-Japan Utstein Registry. Blunt trauma patients with TCA who received prehospital epinephrine were compared with those who did not receive prehospital epinephrine. The primary outcome was 1-month survival of patients. The secondary outcome was prehospital return of spontaneous circulation (ROSC). A total of 5,204 patients with TCA were analyzed. Of those, 758 patients (14.6%) received prehospital epinephrine (Epinephrine group), whereas the remaining 4,446 patients (85.4%) did not receive prehospital epinephrine (No epinephrine group). Eleven (1.5%) and 41 (0.9%) patients in the Epinephrine and No epinephrine groups, respectively, survived for 1 month. In addition, 74 (9.8%) and 40 (0.9%) patients achieved prehospital ROSC in the Epinephrine and No epinephrine groups, respectively. In multivariable logistic regression models, prehospital epinephrine administration was not associated with 1-month survival (odds ratio [OR] 1.495, 95% confidence interval [CI] 0.758 to 2.946) and was associated with prehospital ROSC (OR 3.784, 95% CI 2.102 to 6.812). A propensity score-matched analysis showed similar results for 1-month survival (OR 2.363, 95% CI 0.606 to 9,223) and prehospital ROSC (OR 6.870, 95% CI 3.326 to 14.192). Prehospital epinephrine administration in patients with TCA was not associated with 1-month survival, but was beneficial in regard to prehospital ROSC.

CXCR4 Cardiac Specific Knockout Mice Develop a Progressive Cardiomyopathy

Activation of multiple pathways is associated with cardiac hypertrophy and heart failure. We previously published that CXCR4 negatively regulates β-adrenergic receptor (β-AR) signaling and ultimately limits β-adrenergic diastolic (Ca²⁺) accumulation in cardiac myocytes. In isolated adult rat cardiac myocytes; CXCL12 treatment prevented isoproterenol-induced hypertrophy and interrupted the calcineurin/NFAT pathway. Moreover; cardiac specific CXCR4 knockout mice show significant hypertrophy and develop cardiac dysfunction in response to chronic catecholamine exposure in an isoproterenol-induced (ISO) heart failure model. We set this study to determine the structural and functional consequences of CXCR4 myocardial knockout in the absence of exogenous stress. Cardiac phenotype and function were examined using (1) gated cardiac magnetic resonance imaging (MRI); (2) terminal cardiac catheterization with in vivo hemodynamics; (3) histological analysis of left ventricular (LV) cardiomyocyte dimension; fibrosis; and; (4) transition electron microscopy at 2-; 6- and 12-months of age to determine the regulatory role of CXCR4 in cardiomyopathy. Cardiomyocyte specific-CXCR4 knockout (CXCR4 cKO) mice demonstrate a progressive cardiac dysfunction leading to cardiac failure by 12-months of age. Histological assessments of CXCR4 cKO at 6-months of age revealed significant tissue fibrosis in knockout mice versus wild-type. The expression of atrial naturietic factor (ANF); a marker of cardiac hypertrophy; was also increased with a subsequent increase in gross heart weights. Furthermore, there were derangements in both the number and the size of the mitochondria within CXCR4 cKO hearts. Moreover, CXCR4 cKO mice were more sensitive to catocholamines, their response to β-AR agonist challenge via acute isoproterenol (ISO) infusion demonstrated a greater increase in ejection fraction, dp/dt_max, and contractility index. Interestingly, prior to ISO infusion, there were significant differences in baseline hemodynamics between the CXCR4 cKO compared to littermate controls. However, upon administering ISO, the CXCR4 cKO responded in a robust manner overcoming the baseline hemodynamic deficits reaching WT values supporting our previous data that CXCR4 negatively regulates β-AR signaling. This further supports that, in the absence of the physiologic negative modulation, there is an overactivation of down-stream pathways, which contribute to the development and progression of contractile dysfunction. Our results demonstrated that CXCR4 plays a non-developmental role in regulating cardiac function and that CXCR4 cKO mice develop a progressive cardiomyopathy leading to clinical heart failure.

Cardiac syncope recurrence in type 2 diabetes mellitus patients vs. normoglycemics patients: The CARVAS study

STUDY HYPOTHESIS

Cardiac autonomic dysfunction might lead to higher vaso vagal syncope (VVS) recurrence rate in type 2 diabetes mellitus (T2DM) patients vs. non diabetics patients.

BACKGROUND

VVS recurrence might be due to alterations of autonomic system function, as assessed by heart rate variability (HRV). To date, in this study we investigated the correlation between HRV alterations and VVS recurrence at 12 months of follow up in T2DM vs. non T2DM patients.

MATERIALS AND METHODS

In a prospective multicenter study we studied a propensity score matching (PSM) analysis of 121 T2DM vs. 121 non T2DM patients affected by VVS.

RESULTS

T2DM vs. non T2DM patients had at baseline a higher rate of HRV dysfunction, and this was linked to higher rate of VVS recurrence at 12 months of follow up (p < 0.05). Blood pressure alterations and lower LF/HF ratio were linked to higher rate of all cause syncope recurrence, and of vasodepressor, cardio inhibitory, and mixed syncope recurrence (p < 0.05). Anti hypertensive drug therapies increased the number of vasodepressor and mixed syncope events (p < 0.05); alterations of heart rate increased syncope recurrence and mixed syncope recurrence events (p < 0.05). Finally, T2DM was linked to higher rate of VVS recurrence, and specifically of vasodepressor and mixed VVS recurrence (p < 0.05).

CONCLUSIONS

T2DM patients have alterations of the autonomic nervous system, as result of cardiac autonomic neuropathy. However, T2DM diagnosis and autonomic dysfunction assessed by HRV alterations predicted VVS recurrence.

Clinical efficacy of carvedilol treatment for dilated cardiomyopathy: A meta-analysis of randomized controlled trials

BACKGROUND

Clinical trials examining the therapeutic benefit of carvedilol on patients with dilated cardiomyopathy have reported inconsistent results. The aim of this study was to evaluate the clinical efficacy of carvedilol on patients with dilated cardiomyopathy.

METHODS

PubMed, Embase, Cochrane Library, web of science, China National Knowledge Infrastructure (CNKI), Wanfang, and Chinese Scientific and Technological Journal (VIP) databases were searched for randomized controlled trials (RCTs) before March 2018. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were used to evaluate the effects of carvedilol on patients with dilated cardiomyopathy.

RESULTS

Twenty one studies including 1146 participants were included. There were significant improvements on heart rate (HR) (WMD = -14.18, 95% CI: -17.72 to -10.63, P < .001), LVEF (WMD = 7.28, 95% CI: 6.53-8.03, P < .001), SBP (WMD = -10.74, 95% CI: -12.78 to -8.70, P < .001), DBP (WMD = -4.61, 95% CI: -7.32 to -1.90, P = .001), LVEDD (WMD = -2.76, 95% CI: -4.89 to -0.62, P = .011), LVESD (WMD = -3.63, 95% CI: -6.55 to -0.71, P = .015), LVEDV (WMD = -9.30, 95% CI: -11.89 to -6.71, P < .001), LVESV (WMD = -12.28, 95% CI: -14.86 to -9.70, P < .001) under carvedilol treatment compared with control.

CONCLUSION

This meta-analysis demonstrates that carvedilol significantly improves cardiac function on patients with dilated cardiomyopathy. Further large scale, high-quality and multicenter RCTs are still required to confirm the impacts of carvedilol on patients with dilated cardiomyopathy.

Transcriptomics of cardiac biopsies reveals differences in patients with or without diagnostic parameters for heart failure with preserved ejection fraction

Heart failure affects 2–3% of adult Western population. Prevalence of heart failure with preserved left ventricular (LV) ejection fraction (HFpEF) increases. Studies suggest HFpEF patients to have altered myocardial structure and functional changes such as incomplete relaxation and increased cardiac stiffness. We hypothesised that patients undergoing elective coronary bypass surgery (CABG) with HFpEF characteristics would show distinctive gene expression compared to patients with normal LV physiology. Myocardial biopsies for mRNA expression analysis were obtained from sixteen patients with LV ejection fraction ≥45%. Five out of 16 patients (31%) had echocardiographic characteristics and increased NTproBNP levels indicative of HFpEF and this group was used as HFpEF proxy, while 11 patients had Normal LV physiology. Utilising principal component analysis, the gene expression data clustered into two groups, corresponding to HFpEF proxy and Normal physiology, and 743 differentially expressed genes were identified. The associated top biological functions were cardiac muscle contraction, oxidative phosphorylation, cellular remodelling and matrix organisation. Our results also indicate that upstream regulatory events, including inhibition of transcription factors STAT4, SRF and TP53, and activation of transcription repressors HEY2 and KDM5A, could provide explanatory mechanisms to observed gene expression differences and ultimately cardiac dysfunction in the HFpEF proxy group.

GRKs and β-Arrestins: "Gatekeepers" of Mitochondrial Function in the Failing Heart

Mitochondrial regulation of energy production, calcium homeostasis, and cell death are critical for cardiac function. Accordingly, the structural and functional abnormalities of these organelles (mitochondrial dysfunction) contribute to developing cardiovascular diseases and heart failure. Therefore the preservation of mitochondrial integrity is essential for cardiac cell survival. Mitochondrial function is regulated by several proteins, including GRK2 and β-arrestins which act in a GPCR independent manner to orchestrate intracellular signaling associated with key mitochondrial processes. It is now ascertained that GRK2 is able to recover mitochondrial function in response to insults. β-arrestins affect several intracellular signaling pathways within the cell which in turn are involved in the regulation of mitochondrial function, but a direct regulation of mitochondria needs further investigations. In this review, we discuss the recent acquisitions on the role of GRK2 and β-arrestins in the regulation of mitochondrial function.

Impact of short-acting loop diuretic doses and cardiac sympathetic nerve abnormalities on outcomes of patients with reduced left ventricular function

Recent studies reported that high doses of short-acting loop diuretics are associated with poor outcomes in patients with heart failure (HF). Short-acting loop diuretics have been shown to activate the renin-angiotensin system (RAS) and have no favorable effects on cardiac sympathetic nervous system (SNS) activity. The goal of this study is to investigate the relationship between daily doses of furosemide and the outcomes of patients with left ventricular dysfunction (LVD) from the viewpoint of cardiac SNS abnormalities using iodine-123-labeled metaiodobenzylguanidine (l-MIBG) myocardial scintigraphy.We enrolled 137 hospitalized patients (62.5 ± 14.2 years old, 103 men) with LVEF < 45% who underwent l-MIBG myocardial scintigraphy. A delayed heart-to-mediastinum ratio (delayed HMR) was assessed using l-MIBG scintigraphy. Cardiac events were defined as cardiac death or re-hospitalization due to the deterioration of HF. Cox proportional hazard analysis was used to identify predictors of cardiac events.Cardiac events occurred in 57 patients in a follow-up period of 33.1 ± 30 months. In a multivariate Cox proportional hazard analysis, delayed HMR and furosemide doses were identified as independent predictors of cardiac events (P = .0042, P = .033, respectively). Inverse probability of treatment weighting Cox modeling showed that the use of furosemide (≥40 mg /day) was associated with cardiac events with a hazard ratio of 1.96 (P = .003). In the Kaplan-Mayer analysis, the cardiac event-free survival rate was significantly lower in patients treated with high doses of furosemide (≥60 mg/day vs 40-60 mg/day vs <40 mg/day, the Log-rank test P < .0001). In a receiver-operating characteristic (ROC) analysis, the cut-off value for cardiac events was 40 mg/day of furosemide. The cardiac event-free rate was significantly lower in patients with delayed HMR <1.8 (median value) and receiving furosemide ≥40 mg/day than in other patients (the Log-rank test P < .0001). Significant differences in cardiac event rates according to furosemide doses among patients with delayed HMR <1.8 were observed among patients without β-blocker therapy (P = .001), but not among those with β-blocker therapy (P = .127).The present results indicate that a relationship exists between higher doses of furosemide and poor outcomes. The prognosis of HF patients with severe cardiac SNS abnormalities receiving high-dose short-acting loop diuretics is poor.

Age-dependent changes in cardiac performance, motor function, QoL, and mental status in metoprolol-treated chronic heart failure patients

No previous study reports the effect of age on cardiac performance, motor function and quality of life (QoL) in Chinese chronic heart failure (CHF) patients. This single-center, prospective study enrolled CHF patients with resting heart rate (RHR) > 80 bpm, who were treated with metoprolol and were followed up at 1, 3, 6, and 12 months. Changes in cardiac, motor, and QoL parameters between patients aged ≥60 years and those aged <60 years were compared at all time points. P < 0.05 was considered significant. A total of 154 patients were enrolled (median age: 66.39 years; 116 aged ≥60 years, 38 aged <60 years; 95% New York Heart Association class III-IV). RHR decreased significantly in both patient groups (P < 0.0001 for both groups). Patients aged ≥60 years had a significant improvement in both ejection fraction (EF) at 6 and 12 months and in cardiac index (CI) at 3, 6, and 12 months. However, no major difference was observed in motor function in both groups. Significantly higher SF-8 scores showed greater improvement in QoL in the <60 age group at 12 months (P = 0.0008). Metoprolol demonstrated improvement in cardiac performance, motor function, QoL, and anxiety with increase in depression and burnout in both genders; however, the findings were independent of age.

Fucoidan⁻Fucoxanthin Ameliorated Cardiac Function via IRS1/GRB2/ SOS1, GSK3β/CREB Pathways and Metabolic Pathways in Senescent Mice

The effects of low molecular weight fucoidan (LMWF) in combination with high-stability fucoxanthin (HSFUCO) on cardiac function and the metabolic pathways of aging mice (Mus musculus) were investigated. We demonstrated that LMWF and HSFUCO could improve cardiac function in aging mice. Aging mice were treated with LMWF and HSFUCO, either on their own or in combination, on 28 consecutive days. Electrocardiography and whole-cell patch-clamp were used to measure QT interval and action potential duration (APD) of the subjects. Cardiac tissue morphology, reactive oxygen species, and Western blot were also applied. Ultra-high-performance liquid chromatography⁻quadrupole time-of-flight (UPLC-QTOF) mass spectrometry was used for investigating metabolic alterations. The use of LMWF and HSFUCO resulted in improvements in both ventricular rhythms (QT and APD). Treatment with fucoidan and fucoxanthin reduced the expression levels of SOS1 and GRB2 while increasing GSK3β, CREB and IRS1 proteins expression in the aging process. Three main metabolic pathways, namely the TCA cycle, glycolysis, and steroid hormone biosynthesis, were highly enriched in the pathway enrichment analysis. When taken together, the LMWF and HSFUCO treatment improved both the ventricular rhythm and the muscular function of aging subjects by interfering with the metabolism and gene function.

Differences in nutritional status and activities of daily living and mobility in elderly hospitalized patients with heart failure

Aims

This study aims to examine the effect of differences in nutritional status on activities of daily living (ADL) and mobility recovery of hospitalized elderly patients with heart failure (HF).

Methods and results

From among 377 consecutive HF patients who underwent rehabilitation at one acute‐care hospital from January 2013 to August 2015, those who were aged ≥ 65 years could walk with assistance before hospitalization and who were hospitalized for the first time were included in this retrospective cohort study. Exclusion criteria were pacemaker surgery during hospitalization, change to other departments, death during hospitalization, and unmeasured ADL. We investigated patient characteristics, basic attributes, Geriatric Nutritional Risk Index (GNRI), ADL [motor Functional Independence Measure (motor FIM)], and Rivermead Mobility Index (RMI). Of these 377 patients, 96 met the inclusion criteria and were divided into the low GNRI group (n = 38, 83.5 ± 8.3 years, 44.7% male) and high GNRI group (n = 58, 81.0 ± 6.6 years, 55.2%). Patient characteristics and the difference between motor ADL and motility recovery and nutrition data were analysed with unpaired t‐test, χ² test, and two‐way analysis of covariance. In comparing the two groups, the following parameters were significantly lower in the low GNRI group than in the high GNRI group: body mass index (18.7 ± 2.2 vs. 23.2 ± 2.7 kg/m², P < 0.01), albumin (3.4 ± 0.4 vs. 3.8 ± 0.4 g/dL, P < 0.01), diabetes mellitus ratio (21.1% vs. 50.0%, P < 0.01), RMI at discharge (6.8 ± 2.6 vs. 8.2 ± 2.2, P = 0.01), and motor FIM at discharge (67.2 ± 19.5 vs. 75.6 ± 13.3, P = 0.02). RMI showed a significant group and term main effect and interaction effect (P < 0.05). Motor FIM showed a significant main effect of group and term (P < 0.05), and no significant interaction effect.

Conclusions

Low nutritional status in hospitalized elderly HF patients affected their recovery of mobility but did not appear to affect the recovery of ADL.

Plasma Low-Density Lipoprotein Cholesterol Correlates With Heart Function in Individuals With Type 2 Diabetes Mellitus: A Cross-Sectional Study

Background: Heart failure is a frequent complication of type 2 diabetes mellitus (T2DM). Plasma cholesterol, particularly the proatherogenic low-density lipoprotein (LDL) cholesterol, impairs heart function by promoting atheroma formation and ventricular dysfunction. Considering the established effect of cholesterol on the cardiovascular system, we hypothesized that plasma LDL cholesterol may influence left ventricular function in individuals with T2DM. Methods: This cross-sectional study was conducted at a tertiary care hospital in Taiwan. Enrollment criteria were patients exceeding 21 years of age with T2DM who received antidiabetic and cholesterol-lowering medications. Candidates were excluded if they had heart failure, acute cardiovascular events, or familial hypercholesterolemia. Participants received blood sampling for plasma lipids after a 12-h fast, followed by transthoracic echocardiography in the cardiology clinic. Results: The study enrolled 118 participants who were divided into two groups according to their plasma LDL cholesterol levels. Demographic characteristics including age (69.7 vs. 66.9 years, P = 0.159), body mass index (26.2 vs. 25.9 kg/m², P = 0.66), diabetes duration (5.4 vs. 5.1 years, P = 0.48), hemoglobin A_1c (7.2 vs. 7.5%, P = 0.225), and systolic blood pressure (129 vs. 130 mm Hg, P = 0.735) were similar between these groups. Moreover, all participants received similar antihypertensive medications. Participants with lower plasma LDL cholesterol levels had better heart function, as measured by the left ventricular ejection fraction (LVEF), than patients with higher LDL cholesterol levels (58.0 vs. 50.5%, P = 0.022). Multivariate regression analysis also showed an inverse correlation between plasma LDL cholesterol and left ventricular function (β coefficient: -0.110, P = 0.024). Conclusion: This study observed an inverse correlation between plasma LDL cholesterol and heart function in individuals with T2DM. Patients with higher levels of plasma LDL cholesterol had worse left ventricular function. Therefore, plasma LDL cholesterol may be a modifiable risk factor of heart failure in diabetes, but prospective studies are necessary to confirm this finding.

Monoamine oxidase-A is a novel driver of stress-induced premature senescence through inhibition of parkin-mediated mitophagy

Cellular senescence, the irreversible cell cycle arrest observed in somatic cells, is an important driver of age‐associated diseases. Mitochondria have been implicated in the process of senescence, primarily because they are both sources and targets of reactive oxygen species (ROS). In the heart, oxidative stress contributes to pathological cardiac ageing, but the mechanisms underlying ROS production are still not completely understood. The mitochondrial enzyme monoamine oxidase‐A (MAO‐A) is a relevant source of ROS in the heart through the formation of H₂O₂ derived from the degradation of its main substrates, norepinephrine (NE) and serotonin. However, the potential link between MAO‐A and senescence has not been previously investigated. Using cardiomyoblasts and primary cardiomyocytes, we demonstrate that chronic MAO‐A activation mediated by synthetic (tyramine) and physiological (NE) substrates induces ROS‐dependent DNA damage response, activation of cyclin‐dependent kinase inhibitors p21^cip, p16^ink4a, and p15^ink4b and typical features of senescence such as cell flattening and SA‐β‐gal activity. Moreover, we observe that ROS produced by MAO‐A lead to the accumulation of p53 in the cytosol where it inhibits parkin, an important regulator of mitophagy, resulting in mitochondrial dysfunction. Additionally, we show that the mTOR kinase contributes to mitophagy dysfunction by enhancing p53 cytoplasmic accumulation. Importantly, restoration of mitophagy, either by overexpression of parkin or inhibition of mTOR, prevents mitochondrial dysfunction and induction of senescence. Altogether, our data demonstrate a novel link between MAO‐A and senescence in cardiomyocytes and provides mechanistic insights into the potential role of MAO‐dependent oxidative stress in age‐related pathologies.