Silencing of microRNA-106b-5p prevents doxorubicin-mediated cardiotoxicity through modulation of the PR55α/YY1/sST2 signaling axis.

Clinical use of doxorubicin (Dox), an anthracycline with potent anti-tumor effects, is limited because of its highly chemotherapy-induced cardiotoxicity (CIC). After myocardial infarction (MI), we have recently identified Yin Yang-1 (YY1) and histone deacetylase 4 (HDAC4) as two factors involved in the overexpression of the isoform soluble suppression of tumorigenicity 2 (sST2) protein, which acts as a decoy receptor blocking the favorable effects of IL-33. Therefore, high levels of sST2 are associated with increased fibrosis, remodeling, and worse cardiovascular outcomes. No data exist on the role of the YY1/HDAC4/sST2 axis in CIC. This study aimed to evaluate the pathophysiological implication of the molecular YY1/HDAC4/sST2 axis in remodeling that is developed in patients treated with Dox as well as to suggest a novel molecular therapy to prevent anthracycline-induced cardiotoxicity. Here, we have characterized a novel nexus between miR106b-5p (miR-106b) levels and the YY1/HDAC4 axis in relation to the cardiac expression of sST2 using two experimental models with Dox-induced cardiotoxicity. The addition of Dox (5 µM) to human induced pluripotent stem cell-derived cardiomyocytes induced cellular apoptotic death via upregulation of miR-106b-5p (miR-106b), which was confirmed by specific mimic sequences. A functional blockage of miR-106b using the locked nucleic acid antagomir inhibited Dox-induced cardiotoxicity.

Critical warm ischemia time point for cardiac donation after circulatory death.

Donation after circulatory death (DCD) represents a promising opportunity to overcome the relative shortage of donors for heart transplantation. However, the necessary period of warm ischemia is a concern. This study aims to determine the critical warm ischemia time based on in vivo biochemical changes. Sixteen DCD non-cardiac donors, without cardiovascular disease, underwent serial endomyocardial biopsies immediately before withdrawal of life-sustaining therapy (WLST), at circulatory arrest (CA) and every 2 min thereafter. Samples were processed into representative pools to assess calcium homeostasis, mitochondrial function and cellular viability. Compared to baseline, no significant deterioration was observed in any studied parameter at the time of CA (median: 9 min; IQR: 7-13 min; range: 4-19 min). Ten min after CA, phosphorylation of cAMP-dependent protein kinase-A on Thr197 and SERCA2 decreased markedly; and parallelly, mitochondrial complex II and IV activities decreased, and caspase 3/7 activity raised significantly. These results did not differ when donors with higher WLST to CA times (≥9 min) were analyzed separately. In human cardiomyocytes, the period from WLST to CA and the first 10 min after CA were not associated with a significant compromise in cellular function or viability. These findings may help to incorporate DCD into heart transplant programs.

The miRNA199a/SIRT1/P300/Yy1/sST2 signaling axis regulates adverse cardiac remodeling following MI.

Left ventricular remodeling following myocardial infarction (MI) is related to adverse outcome. It has been shown that an up-regulation of plasma soluble ST2 (sST2) levels are associated with lower pre-discharge left ventricular (LV) ejection fraction, adverse cardiovascular outcomes and mortality outcome after MI. The mechanisms involved in its modulation are unknown and there is not specific treatment capable of lowering plasma sST2 levels in acute-stage HF. We recently identified Yin-yang 1 (Yy1) as a transcription factor related to circulating soluble ST2 isoform (sST2) expression in infarcted myocardium. However, the underlying mechanisms involved in this process have not been thoroughly elucidated. This study aimed to evaluate the pathophysiological implication of miR-199a-5p in cardiac remodeling and the expression of the soluble ST2 isoform. Myocardial infarction (MI) was induced by permanent ligation of the left anterior coronary artery in C57BL6/J mice that randomly received antimiR199a therapy, antimiR-Ctrl or saline. A model of biomechanical stretching was also used to characterize the underlying mechanisms involved in the activation of Yy1/sST2 axis. Our results show that the significant upregulation of miR-199a-5p after myocardial infarction increases pathological cardiac hypertrophy by upregulating circulating soluble sST2 levels. AntimiR199a therapy up-regulates Sirt1 and inactivates the co-activator P300 protein, thus leading to Yy1 inhibition which decreases both expression and release of circulating sST2 by cardiomyocytes after myocardial infarction. Pharmacological inhibition of miR-199a rescues cardiac hypertrophy and heart failure in mice, offering a potential therapeutic approach for cardiac failure.

Author Correction: Empagliflozin improves post-infarction cardiac remodeling through GTP enzyme cyclohydrolase 1 and irrespective of diabetes status.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Empagliflozin improves post-infarction cardiac remodeling through GTP enzyme cyclohydrolase 1 and irrespective of diabetes status.

Sodium-glucose co-transporter-2 inhibitors (SGLT2i) have shown to prevent heart failure progression, although the mechanisms remain poorly understood. Here we evaluated the effect of empagliflozin (EMPA, SGLT2i) in cardiac remodeling after myocardial infarction, the interplay with diabetes status and the role of cardiac GTP enzyme cyclohydrolase 1 (cGCH1). A rat model of diabetes (50 mg/kg streptozotocin, i.p.) was subjected to myocardial infarction and left ventricular systolic dysfunction, by ligation of the left anterior descending coronary artery. EMPA therapy significantly improved cardiac remodeling parameters and ameliorated processes of fibrosis and hypertrophy, in both non-diabetic and diabetic rats. This cardioprotective effect related with a significant increase in myocardial expression levels of cGCH1, which led to activation of nNOS and eNOS, and inhibition of iNOS, and subsequently resulted in increasing of NO levels and decreasing O2.- and nitrotyrosine levels. These effects were replicated in a cardiomyocyte biomechanical stretching diabetic model, where silencing cGCH1 blocked the preventive effect of EMPA. The beneficial effects were observed irrespective of diabetes status, although the magnitude was greater in presence of diabetes. Empagliflozin improves myocardial remodeling after myocardial infarction through overexpression of cGCH1, and irrespective of diabetes status.

The Interleukin-1 Axis and Risk of Death in Patients With Acutely Decompensated Heart Failure.

BACKGROUND: Soluble ST2 (sST2), which is the soluble form of interleukin (IL)-1 receptor-like 1, identifies risk in acutely decompensated heart failure (ADHF). IL-1ß is an inflammatory cytokine that has deleterious effects in myocardial remodeling and function. IL-1ß inhibition has beneficial effects after acute myocardial infarction. However, the role of IL-1ß in ADHF and its relationship to ST2 remain unclear. OBJECTIVES: This study sought to investigate the relationship between IL-1ß and sST2, and the prognostic impact of such a relationship in patients with ADHF. METHODS: This study examined 316 consecutive patients who were hospitalized with ADHF (72 ± 12 years of age, 57% male, and left ventricular ejection fraction 45 ± 17%). Blood samples were collected at presentation, and IL-1ß and sST2 levels were measured. All-cause mortality was obtained for all patients at 1 year. RESULTS: The IL-1ß concentration at presentation was associated with prior HF hospitalizations, functional impairment, and higher N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin T concentrations. IL-1ß was higher in patients who died during the year after hospitalization (n = 52, 16.5%) (p = 0.005), and the optimal threshold was identified with levels over 49.1 pg/ml (hazard ratio: 2.5; 95% confidence interval: 1.43 to 4.49; p = 0.0014). Circulating IL-1ß positively correlated with sST2 (ρ = 0.65; p < 0.001). Considering the prognostic thresholds of IL-1ß (≥49.1 pg/ml) and sST2 (≥35.0 ng/ml) concentrations: all patients with low sST2 also presented with low IL-1ß; among patients with high sST2, only those with also high IL-1ß had a significantly higher risk of death (30% vs. 14%; hazard ratio: 2.52; 95% confidence interval: 1.40 to 4.56; p = 0.002). CONCLUSIONS: Circulating IL-1ß concentrations are clinically meaningful in ADHF patients and interplay with the predictive ability of sST2. IL-1 axis-related inflammation signaling may represent a therapeutic target in ADHF.

Unraveling the Molecular Mechanism of Action of Empagliflozin in Heart Failure With Reduced Ejection Fraction With or Without Diabetes.

The mechanism of action of empagliflozin in heart failure with reduced ejection fraction (HFrEF) was deciphered using deep learning in silico analyses together with in vivo validation. The most robust mechanism of action involved the sodium-hydrogen exchanger (NHE)-1 co-transporter with 94.7% accuracy, which was similar for diabetics and nondiabetics. Notably, direct NHE1 blockade by empagliflozin ameliorated cardiomyocyte cell death by restoring expression of X-linked inhibitor of apoptosis (XIAP) and baculoviral IAP repeat-containing protein 5 (BIRC5). These results were independent of diabetes mellitus comorbidity, suggesting that empagliflozin may emerge as a new treatment in HFrEF.

Pulmonary Production of Soluble ST2 in Heart Failure.

BACKGROUND: Serum concentrations of ST2 (interleukin-1 receptor-like 1) represent a meaningful prognostic marker in cardiac diseases. Production of soluble ST2 (sST2) may be partially extracardiac. Identification of sST2 sources is relevant to design strategies for modulating its signaling. METHODS AND RESULTS: An experimental model of ischemic heart failure was used. sST2, membrane-bound ST2 (ST2L), and IL-33 were measured in lungs, heart, kidney, and liver by quantifying mRNA and protein expression in tissue samples obtained at different times (1, 2, 4, and 24 weeks). Primary human type II pneumocyte cell cultures were subjected to strain. sST2 was measured in samples of bronchial aspirate and serum obtained from patients treated with invasive respiratory support. In the experimental model, sST2 increased significantly from the first week in both lungs and myocardium, whereas ST2L/IL-33 response was unfavorable in lungs (decrease) and favorable in myocardium (increase). No changes were observed in liver and kidneys. ST2 immunostaining was intensely observed in alveolar epithelium, and sST2 was secreted by primary human type II pneumocytes in response to strain. sST2 levels in lung aspirates were substantially higher in the presence of cardiogenic pulmonary edema (median, 228 [interquartile range, 28.4-324.0] ng/mL; P<0.001) than bronchopneumonia (median, 5.5 [interquartile range, 1.6-6.5]) or neurological disorders (median, 2.9 [interquartile range, 1.7-10.1]), whereas sST2 concentrations in serum did not differ. CONCLUSIONS: The lungs are a relevant source of sST2 in heart failure. These results may have implications for the progression of disease and the development of therapies targeting the ST2 system in patients with heart failure.

Pharmacological inhibition of the mitochondrial NADPH oxidase 4/PKCα/Gal-3 pathway reduces left ventricular fibrosis following myocardial infarction.

Although the initial reparative fibrosis after myocardial infarction (MI) is crucial for preventing rupture of the ventricular wall, an exaggerated fibrotic response and reactive fibrosis outside the injured area are detrimental. Although metformin prevents adverse cardiac remodeling, as well as provides glycemic control, the underlying mechanisms remain poorly documented. This study describes the effect of mitochondrial NADPH oxidase 4 (mitoNox) and protein kinase C-alpha (PKCα) on the cardiac fibrosis and galectin 3 (Gal-3) expression. Randomly rats underwent MI, received metformin or saline solution. A model of biomechanical strain and co-culturewas used to enable cross talk between cardiomyocytes and fibroblasts. Long-term metformin treatment after MIwas associated with (1) a reduction in myocardial fibrosis and Gal-3 levels; (2) an increase in adenosine monophosphate-activated protein kinase (AMPK) α1/α2 levels; and (3) an inhibition of both mRNA expression and enzymatic activities of mitoNox and PKCα. These findings were replicated in the cellular model, where the silencing of AMPK expression blocked the ability of metformin to protect cardiomyocytes from strain. The use of specific inhibitors or small interference RNA provided evidence that PKCα is downstream of mitoNox, and that the activation of this pathway results in Gal-3 upregulation.The Gal-3 secreted by cardiomyocytes has a paracrine effect on cardiac fibroblasts, inducing their activation. In conclusion, a metformin-induced increase in AMPK improves myocardial remodeling post-MI, which is related to the inhibition of the mitoNox/PKCα/Gal-3 pathway. Manipulation of this pathway might offer new therapeutic options against adverse cardiac remodeling, in terms of preventing the activation of the present fibroblast population.

Early Anti-inflammatory and Pro-angiogenic Myocardial Effects of Intravenous Serelaxin Infusion for 72 H in an Experimental Rat Model of Acute Myocardial Infarction.

Sprague Dawley rats were subjected to acute myocardial infarction (AMI) by permanent ligation of the left anterior descending coronary artery. At the time of AMI, a subcutaneous mini-osmotic pump was implanted and animals were randomized into three groups, according to the intravenous therapy received during the first 72 h: placebo-treated (saline), serelaxin10-treated (SRLX10 = 10 µg/kg/day), or serelaxin30-treated (SRLX30 = 30 µg/kg/day). Treatment with SRLX30 reduced the expression of inflammatory cytokines and chemokines, as well as the infiltration of macrophages, and increased the expression of pro-angiogenic markers and vessel density in the infarcted myocardium after 7 days. SRLX30 did not reduce early myocardial fibrosis but reduced myocardial levels of sST2 and galectin-3. No significant effects were observed with SRLX10 treatment. A significant correlation was observed between plasma levels of serelaxin and effect measures. The results suggest serelaxin has a protective effect in early processes of cardiac remodeling after AMI.

Doxorubicin-induced oxidative stress: The protective effect of nicorandil on HL-1 cardiomyocytes.

The primary cardiotoxic action of doxorubicin when used as antitumor drug is attributed to the generation of reactive oxygen species (ROS) therefore effective cardioprotection therapies are needed. In this sense, the antianginal drug nicorandil has been shown to be effective in cardioprotection from ischemic conditions but the underlying molecular mechanism to cope with doxorubicin-induced ROS is unclear. Our in vitro study using the HL-1 cardiomyocyte cell line derived from mouse atria reveals that the endogenous nitric oxide (NO) production was stimulated by nicorandil and arrested by NO synthase inhibition. Moreover, while the NO synthase activity was inhibited by doxorubicin-induced ROS, the NO synthase inhibition did not affect doxorubicin-induced ROS. The inhibition of NO synthase activity by doxorubicin was totally prevented by preincubation with nicorandil. Nicorandil also concentration-dependently (10 to 100 µM) decreased doxorubicin-induced ROS and the effect was antagonized by 5-hydroxydecanoate. The inhibition profile of doxorubicin-induced ROS by nicorandil was unaltered when an L-arginine derivative or a protein kinase G inhibitor was present. Preincubation with pinacidil mimicked the effect of nicorandil and the protection was eliminated by glibenclamide. Quantitative colocalization of fluorescence indicated that the mitochondrion was the target organelle of nicorandil and the observed response was a decrease in the mitochondrial inner membrane potential. Interference with H+ movement across the mitochondrial inner membrane, leading to depolarization, also protected from doxorubicin-induced ROS. The data indicate that activation of the mitochondrial ATP-sensitive K+ channel by nicorandil causing mitochondrial depolarization, without participation of the NO donor activity, was responsible for inhibition of the mitochondrial NADPH oxidase that is the main contributor to ROS production in cardiomyocytes. Impairment of the cytosolic Ca2+ signal induced by caffeine and the increase in lipid peroxidation, both of which are indicators of doxorubicin-induced oxidative stress, were also prevented by nicorandil.

Atrial fibrillation management in older heart failure patients: a complex clinical problem.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF), two problems of growing prevalence as a consequence of the ageing population, are associated with high morbidity, mortality, and healthcare costs. AF and HF also share common risk factors and pathophysiologic processes such as hypertension, diabetes mellitus, ischemic heart disease, and valvular heart disease often occur together. Although elderly patients with both HF and AF are affected by worse symptoms and poorer prognosis, there is a paucity of data on appropriate management of these patients. METHODS: PubMed was searched for studies on AF and older patients using the terms atrial fibrillation, elderly, heart failure, cognitive impairment, frailty, stroke, and anticoagulants. RESULTS: The clinical picture of HF patients with AF is complex and heterogeneous with a higher prevalence of frailty, cognitive impairment, and disability. Because of the association of mental and physical impairment to non-administration of oral anticoagulants (OACs), screening for these simple variables in clinical practice may allow better strategies for intervention in this high-risk population. Since novel direct OACs (NOACs) have a more favorable risk-benefit profile, they may be preferable to vitamin K antagonists (VKAs) in many frail elderly patients, especially those at higher risk of falls. Moreover, NOACs are simple to administer and monitor and may be associated with better adherence and safety in patients with cognitive deficits and mobility impairments. CONCLUSIONS: Large multicenter longitudinal studies are needed to examine the effects of VKAs and NOACs on long-term cognitive function and frailty; future studies should include geriatric conditions.

Barriers to cardiac rehabilitation access of older heart failure patients and strategies for better implementation.

In heart failure (HF), cardiac rehabilitation (CR) may reduce decompensations, hospitalization, and ultimately mortality in long term. Many studies over the past decade have demonstrated that aerobic exercise training is effective and safe in stable patients with HF. Exercise CR resulted in a clinically important improvement in the QOL. Several clinical and psychosocial factors are associated with decreased participation in CR programs of elderly HF patients, such as perception of exercise as tiring or painful, comorbidities, lack of physician encouragement, and opinion that CR will not improve their health status. Besides low functional capacity, and chronic deconditioning may also deter patients from participating in CR programs. Recent data suggest that current smoking, a BMI ≥30 kg/m2, diabetes mellitus, and cognitive dysfunction are associated with failure to enroll in outpatient CR in older age group. Moreover the lack of availability of CR facilities or the absence of financial refunds for enrolment of CHF patients in cardiac rehabilitation programs can play a crucial role. Many of this factors are modifiable through patient education and self care strategy instruction, health providers sensibilization, and implementing economic measures in order to make CR affordable.

Cardiac rehabilitation is safe and effective also in the elderly, but don't forget about drugs!

In the setting of heart failure (HF) pharmacotherapy demonstrates a quantifiable improvement in exercise tolerance also in HF with preserved ejection fraction (HFpEF). For patients with HFpEF, often older, with higher prevalence of hypertension, diabetes mellitus, atrial fibrillation and other comorbidities, endpoints such as quality of life and functional capacity may be more clinically relevant. However several study show as the use of ACE-I and B-blocker were lesser than expected. Beta-blocker therapy is the keystone of pharmacotherapy of HF patients and exercise training is the essential core of rehabilitation programs, it is important to elucidate the relationship between these therapies. Exercise training improves the clinical status of HF, improving left ventricular ejection fraction and improving quality of life, but it is possible that b-blocker may attenuate exercise training adaptations. Despite this, possible adverse b-blocker effects are just presumed and not confirmed by published randomized clinical trials. Metanalysis suggests that b-blocker compared with placebo enhances improvements in cardiorespiratory performance in exercise training intervention. Despite these evidences, prescription of gold standard therapy and adherence are still suboptimal and should be a priority goal for all CR program.

The TBX1 Transcription Factor in Cardiac Remodeling After Myocardial Infarction.

INTRODUCTION AND OBJECTIVES: The transcription factor TBX1 plays an important role in the embryonic development of the heart. Nothing is known about its involvement in myocardial remodeling after acute myocardial infarction (AMI) and whether its expression can be modulated by a treatment with proven benefit such as mineralocorticoid receptor blockade. METHODS: Acute myocardial infarction was induced in 60 rats via left coronary artery ligation: 50 animals were randomized to be euthanized after 1, 2, 4, 12, or 24 weeks; 10 animals were treated with eplerenone (100 mg/kg/days) 7 days before the AMI until their euthanasia (4 weeks later); 8 additional animals underwent surgery without ligation (control). We analyzed the cardiac expression of TBX1, fetal genes, and fibrosis markers. RESULTS: The gene and protein expression of TBX1 was increased in the infarcted myocardium, peaking 1 week after AMI (P < .01), without changes in the noninfarcted myocardium. Levels of the fetal genes and fibrosis markers also increased, peaking 4 weeks (P < .001) and 1 week (P < .01) after AMI, respectively. The TBX1 expression was correlated with that of the fibrosis markers (P < .01) but not the fetal genes. Eplerenone reduced the TBX1 increase and fibrosis induced by AMI, with an association improvement in ventricular function and remodeling in echocardiography. CONCLUSIONS: These results show the reactivated expression of TBX1 and indicate its involvement in cardiac fibrosis and remodeling after AMI and its participation in the benefit from mineralocorticoid receptor blockade.

Early oxidative damage induced by doxorubicin: Source of production, protection by GKT137831 and effect on Ca(2+) transporters in HL-1 cardiomyocytes.

In atrial-derived HL-1 cells, ryanodine receptor and Na(+)/Ca(2+)-exchanger were altered early by 5 µM doxorubicin. The observed effects were an increase of cytosolic Ca(2+) at rest, ensuing ryanodine receptor phosphorylation, and the slowing of Ca(2+) transient decay after caffeine addition. Doxorubicin triggered a linear rise of reactive oxygen species (ROS) with no early effect on mitochondrial inner membrane potential. Doxorubicin and ROS were both detected in mitochondria by colocalization with fluorescence probes and doxorubicin-induced ROS was totally blocked by mitoTEMPO. The NADPH oxidase activity in the mitochondrial fraction was sensitive to inhibition by GKT137831, and doxorubicin-induced ROS decreased gradually as the GKT137831 concentration added in preincubation was increased. When doxorubicin-induced ROS was prevented by GKT137831, the kinetic response revealed a permanent degree of protection that was consistent with mitochondrial NADPH oxidase inhibition. In contrast, the ROS induction by doxorubicin after melatonin preincubation was totally eliminated at first but the effect was completely reversed with time. Limiting the source of ROS production is a better alternative for dealing with oxidative damage than using ROS scavengers. The short-term effect of doxorubicin on Ca(2+) transporters involved in myocardiac contractility was dependent on oxidative damage, and so the impairment was subsequent to ROS production.