Preventive and treatment efficiency of dendrosomal nano-curcumin against ISO-induced cardiac fibrosis in mouse model.

Cardiac fibrosis (c-fibrosis) is a critical factor in cardiovascular diseases, leading to impaired cardiac function and heart failure. This study aims to optimize the isoproterenol (ISO)-induced c-fibrosis model and evaluate the therapeutic efficacy of dendrosomal nano-curcumin (DNC) in both in-vitro and in-vivo conditions. Also, we were looking for the differentially expressed genes following the c-fibrosis induction. At the in-vitro condition, primary cardiac fibroblasts were exclusively cultured on collagen-coated or polystyrene plates and, were treated with ISO for fibrosis induction and post-treated or co-treated with DNC. RT-qPCR and flow cytometry analysis indicated that DNC treatment attenuated the fibrotic effect of ISO treatment in these cells. At the in-vivo condition, our findings demonstrated that ISO treatment effectively induces cardiac (and pulmonary) fibrosis, characterized by pro-fibrotic and pro-inflammatory gene expression and IHC (α-SMA, COL1A1, and TGFß). Interestingly, fibrosis symptoms were reduced following the pretreatment, co-treatment, or post-treatment of DNC with ISO. Additionally, the intensive RNAseq analysis suggested the COMP gene is differentially expressed following the c-fibrosis and our RT-qPCR analysis suggested it as a novel potential marker. Overall, our results promise the application of DNC as a potential preventive or therapy agent before and after heart challenges that lead to c-fibrosis.

TongGuanWan Alleviates Doxorubicin- and Isoproterenol-Induced Cardiac Hypertrophy and Fibrosis by Modulating Apoptotic and Fibrotic Pathways.

Heart failure, a major public health issue, often stems from prolonged stress or damage to the heart muscle, leading to cardiac hypertrophy. This can progress to heart failure and other cardiovascular problems. Doxorubicin (DOX), a common chemotherapy drug, and isoproterenol (ISO), a ß-adrenergic agonist, both induce cardiac hypertrophy through different mechanisms. This study investigates TongGuanWan (TGW,), a traditional herbal remedy, for its effects on cardiac hypertrophy and fibrosis in DOX-induced H9c2 cells and ISO-induced mouse models. TGW was found to counteract DOX-induced increases in H9c2 cell surface area (n = 8, p < 0.01) and improve biomarkers like ANP (n = 3, p < 0.01)) and BNP (n = 3, p < 0.01). It inhibited the MAPK pathway (n = 4, p < 0.01) and GATA-4/calcineurin/NFAT-3 signaling, reduced inflammation by decreasing NF-κB p65 translocation, and enhanced apoptosis-related factors such as caspase-3 (n = 3, p < 0.01), caspase-9 (n = 3, p < 0.01), Bax (n = 3, p < 0.01), and Bcl-2 (n = 3, p < 0.01). Flow cytometry showed TGW reduced apoptotic cell populations. In vivo, TGW reduced heart (n = 8~10, p < 0.01), and left ventricle weights (n = 6~7), cardiac hypertrophy markers (n = 3, p < 0.01), and perivascular fibrosis in ISO-induced mice, with Western blot analysis confirming decreased levels of fibrosis-related factors like fibronectin, α-SMA (n = 3, p < 0.05), and collagen type I (n = 3, p < 0.05). These findings suggest TGW has potential as a therapeutic option for cardiac hypertrophy and fibrosis.

KLF6 aggravates myocardial fibrosis by promoting mitochondrial division.

The dysregulation of mitochondrial dynamics in cardiac fibroblasts (CFs) is closely linked to myocardial fibrosis, which can induce cardiac dysfunction and even lead to heart failure. As an essential multifunctional zinc-finger transcriptional factor of cardiovascular remodeling, the role of KLF6 mediating the link between mitochondrial fission and myocardial fibrosis remains unclear. Next, we want to explore whether the effect of KLF6 on mitochondrial fission might influence cardiac fibroblasts, we established a model of Transforming growth factor ß1 (TGF-ß1) and Isoprenaline (ISO)-induced myocardial fibrosis. Here, we found that KLF6 up-regulation in CFs is correlated with myocardial fibrosis. While knockdown of KLF6 suppresses mitochondrial fission and the Keap1/Nrf2 pathway molecules, which alleviates myocardial fibrosis induced by TGF-ß1. Our findings not only clarified the regulation mechanism of mitochondrial fission by KLF6 but also provided a potential therapeutic target for cardiovascular disease.

Novel Combination Therapy for Heart Failure: Trimebutine-Methoxsalen Identified through Synergistic Network Virtual Screening and Experimental Validation.

Combination therapy is increasingly favored by pharmaceutical companies and researchers as an effective way to quickly discover new drugs with excellent efficacy, especially in the treatment of complex diseases. Previously, we successfully developed a computational screening method to identify such combinations, although it fell short in elucidating their synergistic mechanisms. In this work, we have transitioned to a highest single agent (HSA) synergy model for network screening, which streamlines the discovery of promising combinations and facilitates the investigation of their synergistic effects. Through this refined approach, the trimebutine-methoxsalen combination emerged as a promising candidate for heart failure (HF) treatment, exhibiting significant in vitro cardioprotective effects and effectively mitigating isoproterenol (ISO)-induced structural remodeling in the mouse heart. Further mechanistic studies have demonstrated that trimebutine and methoxsalen could synergistically inhibit intracellular calcium overload in myocardial cells and reduce the production of ROS, thus exerting cardioprotective effects. Overall, this study introduces an advanced computational strategy that not only identifies a novel combination therapy against HF but also sheds light on its underlying synergistic mechanisms.

Relationship of Inotropic Effects of Stimulation of ß1- and ß2-Adrenergic Receptors of Isolated Myocardial Fragments with Echocardiography Parameters in Coronary Heart Disease.

We studied the relationship of inotropic responses of the isolated myocardium to stimulation of ß1-and ß2-adrenergic receptors (ß-AR) with echocardiography parameters in 28 patients with coronary heart disease (CHD). Myocardial fragments (trabeculae of the right atrial appendage) were obtained during coronary artery bypass surgery. The inotropic response of the trabeculae was assessed in an isometric mode. Stimulation of ß1-and ß2-AR with agonists was performed against the background of preliminary α-AR blockade. In case of preserved ejection fraction, significant inotropic response of the trabeculae (135 (112; 154)% from the initial contraction amplitude) was observed after ß1-AR stimulation, while in reduced ejection fraction, its significant increase was observed after ß1-AR stimulation (126 (112; 170)% from the initial contraction amplitude). In patients with preserved and reduced ejection fraction, the correlations between the inotropic responses of the trabeculae to ß1-and ß2-AR stimulation and echocardiography parameters were different. The revealed differences reflect the degree of cardiac remodeling under condition of the studied pathology.

Functional cardiac consequences of ß-adrenergic stress-induced injury in a model of Duchenne muscular dystrophy.

Cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD); however, in the mdx mouse model of DMD, the cardiac phenotype differs from that seen in DMD-associated cardiomyopathy. Although some have used pharmacologic stress to stimulate injury and enhance cardiac pathology in the mdx model, many methods lead to high mortality with variable cardiac outcomes, and do not recapitulate the structural and functional cardiac changes seen in human disease. Here, we describe a simple and effective method to enhance the cardiac phenotype model in mdx mice using advanced 2D and 4D high-frequency ultrasound to monitor cardiac dysfunction progression in vivo. mdx and wild-type mice received daily low-dose (2 mg/kg/day) isoproterenol injections for 10 days. Histopathological assessment showed that isoproterenol treatment increased myocyte injury, elevated serum cardiac troponin I levels and enhanced fibrosis in mdx mice. Ultrasound revealed reduced ventricular function, decreased wall thickness, increased volumes and diminished cardiac reserve in mdx compared to wild-type mice. Our findings highlight the utility of challenging mdx mice with low-dose isoproterenol as a valuable model for exploring therapies targeting DMD-associated cardiac pathologies.

Autonomic modulation impacts conduction velocity dynamics and wavefront propagation in the left atrium.

AIMS: Atrial fibrosis and autonomic remodelling are proposed pathophysiological mechanisms in atrial fibrillation (AF). Their impact on conduction velocity (CV) dynamics and wavefront propagation was evaluated. METHODS AND RESULTS: Local activation times (LATs), voltage, and geometry data were obtained from patients undergoing ablation for persistent AF. LATs were obtained at three pacing intervals (PIs) in sinus rhythm (SR). LATs were used to determine CV dynamics and their relationship to local voltage amplitude. The impact of autonomic modulation- pharmacologically and with ganglionated plexi (GP) stimulation, on CV dynamics, wavefront propagation, and pivot points (change in wavefront propagation of ≥90°) was determined in SR. Fifty-four patients were included. Voltage impacted CV dynamics whereby at non-low voltage zones (LVZs) (≥0.5 mV) the CV restitution curves are steeper [0.03 ± 0.03 m/s ΔCV PI 600-400 ms (PI1), 0.54 ± 0.09 m/s ΔCV PI 400-250 ms (PI2)], broader at LVZ (0.2-0.49 mV) (0.17 ± 0.09 m/s ΔCV PI1, 0.25 ± 0.11 m/s ΔCV PI2), and flat at very LVZ (<0.2 mV) (0.03 ± 0.01 m/s ΔCV PI1, 0.04 ± 0.02 m/s ΔCV PI2). Atropine did not change CV dynamics, while isoprenaline and GP stimulation resulted in greater CV slowing with rate. Isoprenaline (2.7 ± 1.1 increase/patient) and GP stimulation (2.8 ± 1.3 increase/patient) promoted CV heterogeneity, i.e. rate-dependent CV (RDCV) slowing sites. Most pivot points co-located to RDCV slowing sites (80.2%). Isoprenaline (1.3 ± 1.1 pivot increase/patient) and GP stimulation (1.5 ± 1.1 increase/patient) also enhanced the number of pivot points identified. CONCLUSION: Atrial CV dynamics is affected by fibrosis burden and influenced by autonomic modulation which enhances CV heterogeneity and distribution of pivot points. This study provides further insight into the impact of autonomic remodelling in AF.

ß-Adrenergic receptor signalling pathway mediated antiarrhythmic activity of s-limonene in the rat heart.

S-Limonene (s-Lim) is a monocyclic monoterpene found in a variety of plants and has been shown to present antioxidant and cardioprotective activity in experimental models of myocardial infarction. The aim of this study was to evaluate the potential mechanism by which s-Lim exerts its antiarrhythmic effect, focusing on the blockade of ß-adrenoceptor (ß-AR) and its effects on various in vivo and in vitro parameters, including electrocardiogram (ECG) measurements, left ventricular developed pressure (LVDP), the ß-adrenergic pathway, sarcomeric shortening and L-type calcium current (ICa,L). In isolated hearts, 10 µM of s-Lim did not alter the ECG profile or LVPD. s-Lim increased the heart rate corrected QT interval (QTc) (10.8%) at 50 µM and reduced heart rate at the concentrations of 30 (12.4%) and 50 µM (16.6%). s-Lim (10 µM) also inhibited the adrenergic response evoked by isoproterenol (ISO) (1 µM) reducing the increased of heart rate, LVDP and ECG changes. In ventricular cardiomyocyte, s-Lim antagonized the effect of dobutamine by preventing the increase of sarcomeric shortening, demonstrating a similar effect to atenolol (blocker ß1-AR). In vivo, s-Lim antagonized the effect of ISO (agonists ß1-AR), presenting a similar effect to propranolol (a non-selective blocker ß-AR). In ventricular cardiomyocyte, s-Lim did not alter the voltage dependence for ICa,L activation or the ICa,L density. In addition, s-Lim did not affect changes in the ECG effect mediated by 5 µM forskolin (an activator of adenylate cyclase). In an in vivo caffeine/ISO-induced arrhythmia model, s-Lim (1 mg/kg) presented antiarrhythmic action verified by a reduced arrhythmia score, heart rate, and occurrence of ventricular premature beats and inappropriate sinus tachycardia. These findings indicate that the antiarrhythmic activity of s-Lim is related to blockade of ß-AR in the heart.

Interleukin(IL)-37 attenuates isoproterenol (ISO)-induced cardiac hypertrophy by suppressing JAK2/STAT3-signaling associated inflammation and oxidative stress.

BACKGROUND: Inflammation and oxidative stress have drawn more and more interest in the realm of cardiovascular disease. In many different disorders, IL-37 acts as an anti-inflammatory and suppressor of inflammation. This study aimed to investigate whether IL-37 could alleviate cardiac hypertrophy by reducing inflammation and oxidative stress. METHODS: In vivo, a cardiac hypertrophy model was induced by 14 d of daily isoproterenol (ISO, 30 mg/kg/d) injection, followed by weeks of treatment with recombinant human IL-37 (1000 ng/animal), administered three times weekly. Assessments concentrated on markers of inflammation and oxidative stress, apoptosis, myocardial disease, and cardiac shape and function. In vitro, neonatal rat cardiomyocytes (NRCMs) were subjected to ISO (10 µM) to establish a cardiomyocytes hypertrophy model. Subsequent IL-37 treatment (100 ng/ml) was applied to determine its cardioprotective efficacy and to elucidate further the underlying mechanisms involved. RESULTS: Significant cardioprotective benefits of IL-37 were seen (in vitro as well as in vivo), primarily through the reduction of oxidative stress, inflammation, apoptosis, and heart hypertrophy markers. Furthermore, IL-37 treatment was associated with a decrease in JAK2 and STAT3 phosphorylation. It is interesting to note that WP1066, a JAK2/STAT3 inhibitor, exhibited antioxidant and anti-inflammatory properties comparable to IL-37, as well as synergistic effects when mixed with the latter. CONCLUSION: ISO-induced cardiac hypertrophy is lessened by IL-37 through the reduction of oxidative stress and inflammation. Additionally, the effects of IL-37 are closely related to inactivation of the JAK2/STAT3 signaling pathway. It is anticipated that IL-37 will one day be used to treat cardiovascular illnesses such as heart hypertrophy.

Anchored PKA synchronizes adrenergic phosphoregulation of cardiac Cav1.2 channels.

Adrenergic modulation of voltage gated Ca2+ currents is a context specific process. In the heart Cav1.2 channels initiate excitation-contraction coupling. This requires PKA phosphorylation of the small GTPase Rad (Ras associated with diabetes) and involves direct phosphorylation of the Cav1.2 α1 subunit at Ser1700. A contributing factor is the proximity of PKA to the channel through association with A-kinase anchoring proteins (AKAPs). Disruption of PKA anchoring by the disruptor peptide AKAP-IS prevents upregulation of Cav1.2 currents in tsA-201 cells. Biochemical analyses demonstrate that Rad does not function as an AKAP. Electrophysiological recording shows that channel mutants lacking phosphorylation sites (Cav1.2 STAA) lose responsivity to the second messenger cAMP. Measurements in cardiomyocytes isolated from Rad-/- mice show that adrenergic activation of Cav1.2 is attenuated but not completely abolished. Whole animal electrocardiography studies reveal that cardiac selective Rad KO mice exhibited higher baseline left ventricular ejection fraction, greater fractional shortening, and increased heart rate as compared to control animals. Yet, each parameter of cardiac function was slightly elevated when Rad-/- mice were treated with the adrenergic agonist isoproterenol. Thus, phosphorylation of Cav1.2 and dissociation of phospho-Rad from the channel are local cAMP responsive events that act in concert to enhance L-type calcium currents. This convergence of local PKA regulatory events at the cardiac L-type calcium channel may permit maximal ß-adrenergic influence on the fight-or-flight response.

Differentiating Left Atrial Pressure Responses in Paroxysmal and Persistent Atrial Fibrillation: Implications for Diagnosing Heart Failure With Preserved Ejection Fraction and Managing Atrial Fibrillation.

BACKGROUND: Increased left atrial pressure (LAP) contributes to dyspnea and heart failure with preserved ejection fraction in patients with atrial fibrillation (AF). The purpose of this study was to investigate the differences in baseline LAP and LAP response to rapid pacing between paroxysmal and persistent AF. METHODS AND RESULTS: This observational study prospectively enrolled 1369 participants who underwent AF catheter ablation, excluding those with reduced left ventricular ejection fraction. H2FPEF score was calculated by echocardiography and baseline characteristics. Patients underwent LAP measurements during AF, sinus rhythm, and heart rates of 90, 100, 110, and 120 beats per minute (bpm), induced by right atrial pacing and isoproterenol. The baseline LAP-peak in the persistent AF group consistently exceeded that in the paroxysmal AF (PAF) group across each H2FPEF score subgroup (all P<0.05). LAP-peak increased with pacing (19.5 to 22.5 mm Hg) but decreased with isoproterenol (20.4 to 18.4 mm Hg). Under pacing, patients with PAF exhibited a significantly lower LAP-peak (90 bpm) than those with persistent AF (17.7±8.2 versus 21.1±9.3 mm Hg, P<0.001). However, there was no difference in LAP-peak (120 bpm) between the 2 groups (22.1±8.1 versus 22.9±8.4 mm Hg, P=0.056) because the LAP-peak significantly increased with heart rate in the group with PAF. CONCLUSIONS: Patients with PAF exhibited lower baseline LAP with greater increases during rapid pacing compared with individuals with persistent AF, indicating a need to revise the H2FPEF score for distinguishing PAF from persistent AF and emphasizing the importance of rate and rhythm control in PAF for symptom control. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT02138695.

Macrophage OTUD1-CARD9 axis drives isoproterenol-induced inflammatory heart remodelling.

BACKGROUND: Chronic inflammation contributes to the progression of isoproterenol (ISO)-induced heart failure (HF). Caspase-associated recruitment domain (CARD) families are crucial proteins for initiation of inflammation in innate immunity. Nonetheless, the relevance of CARDs in ISO-driven cardiac remodelling is little explored. METHODS: This study utilized Card9-/- mice and reconstituted C57BL/6 mice with either Card9-/- or Otud1-/- marrow-derived cells. Mechanistic studies were conducted in primary macrophages, cardiomyocytes, fibroblasts and HEK-293T cells. RESULTS: Here, we demonstrated that CARD9 was substantially upregulated in murine hearts infused with ISO. Either whole-body CARD9 knockout or myeloid-specific CARD9 deletion inhibited ISO-driven murine cardiac inflammation, remodelling and dysfunction. CARD9 deficiency in macrophages prevented ISO-induced inflammation and alleviated remodelling changes in cardiomyocytes and fibroblasts. Mechanistically, we found that ISO enhances the activity of CARD9 by upregulating ovarian tumour deubiquitinase 1 (OTUD1) in macrophages. We further demonstrated that OTUD1 directly binds to the CARD9 and then removes the K33-linked ubiquitin from CARD9 to promote the assembly of the CARD9-BCL10-MALT1 (CBM) complex, without affecting CARD9 stability. The ISO-activated CBM complex results in NF-κB activation and macrophage-based inflammatory gene overproduction, which then enhances cardiomyocyte hypertrophy and fibroblast fibrosis, respectively. Myeloid-specific OTUD1 deletion also attenuated ISO-induced murine cardiac inflammation and remodelling. CONCLUSIONS: These results suggested that the OTUD1-CARD9 axis is a new pro-inflammatory signal in ISO-challenged macrophages and targeting this axis has a protective effect against ISO-induced HF. KEY POINTS: Macrophage CARD9 was elevated in heart tissues of mice under chronic ISO administration. Either whole-body CARD9 knockout or myeloid-specific CARD9 deficiency protected mice from ISO-induced inflammatory heart remodeling. ISO promoted the assembly of CBM complex and then activated NF-κB signaling in macrophages through OTUD1-mediated deubiquitinating modification. OTUD1 deletion in myeloid cells protected hearts from ISO-induced injuries in mice.

Extracellular cAMP elicits contraction of rat vas deferens: Involvement of ecto-5'-nucleotidase and adenosine A1 receptors.

AIMS: It is well established that intracellular cAMP contributes to the relaxation of vas deferens smooth muscle. In many tissues, intracellular cAMP is actively transported to the extracellular space, where it exerts regulatory functions, via its metabolite adenosine. These actions take place through the cAMP conversion to adenosine by ectoenzymes, a process called "extracellular cAMP-adenosine pathway". Herein, we investigated whether, in addition to ATP, extracellular cAMP might be an alternative source of adenosine, influencing the contraction of vas deferens smooth muscle. MAIN METHODS: The effects of cAMP, 8-Br-cAMP and adenosine were analyzed in the isometric contractions of rat vas deferens. cAMP efflux was analyzed by measuring extracellular cAMP levels after exposure of vas deferens segments to isoproterenol and forskolin in the presence or absence of MK-571, an inhibitor of MRP/ABCC transporters. KEY FINDINGS: While 8-Br-cAMP, a cell-permeable cAMP analog, induced relaxation of KCl-precontracted vas deferens, the non-permeant cAMP increased the KCl-induced contractile response, which was mimicked by adenosine, but prevented by inhibitors of ecto-5'-nucleotidase or A1 receptors. Our results also showed that isoproterenol and forskolin increases cAMP efflux via an MRP/ABCC transporter-dependent mechanism, since it is inhibited by MK-571. SIGNIFICANCE: Our data show that activation of ß-adrenoceptors and adenylyl cyclase increases cAMP efflux from vas deferens tissue, which modulates the vas deferens contractile response via activation of adenosine A1 receptors. Assuming that inhibition of vas deferens contractility has been proposed as a strategy for male contraception, the extracellular cAMP-adenosine pathway emerges as a potential pharmacological target that should be considered in studies of male fertility.

Opposite Contractile Effects of Amphetamine-Related Hallucinogenic Drugs in the Isolated Human Atrium.

The present study examined three hallucinogenic amphetamine derivatives, namely, 2,5-dimethoxy-4-iodoamphetamine (DOI) as well as 2,5-dimethoxy-4-methylamphetamine (DOM) and 4-methylmethcathinone (mephedrone). The objective of this study was to test the hypothesis that DOI, DOM, and mephedrone would increase the contractile force in isolated human atrial preparations in a manner similar to amphetamine. To this end, we measured contractile force under isometric conditions in electrically stimulated (1 Hz) human atrial preparations obtained during open surgery. DOI and DOM alone or in the presence of isoprenaline reduced the contractile force concentration-dependently in human atrial preparations. These negative inotropic effects of DOM and DOI were not attenuated by 10 µM atropine. However, mephedrone increased the contractile force in human atrial preparations in a concentration- and time-dependent manner. Furthermore, these effects were attenuated by the subsequent addition of 10 µM propranolol or pretreatment with 10 µM cocaine in the organ bath. Therefore, it can be concluded that amphetamine derivatives may exert opposing effects on cardiac contractile force. The precise mechanism by which DOI and DOM exert their negative inotropic effects remains unknown at present. The cardiac effects of mephedrone are probably due to the release of cardiac noradrenaline.

Astaxanthin ameliorated isoproterenol induced myocardial infarction via improving the mitochondrial function and antioxidant activity in rats.

The present study evaluated the cardioprotective effect of astaxanthin (ASX) against isoproterenol (ISO) induced myocardial infarction in rats via the pathway of mitochondrial biogenesis as the possible molecular target of astaxanthin. The control group was injected with normal physiological saline subcutaneously for 2 days. The second group was injected with ISO at a dose of 85 mg/kg bwt subcutaneously for 2 days. The third, fourth and fifth groups were supplemented with ASX at doses of 10, 20, 30 mg/kg bwt, respectively daily by oral gavage for 21 days then injected with ISO dose of 85 mg/kg bwt subcutaneously for 2 successive days. Isoproterenol administration in rats elevated the activities of Creatine kinase-MB (CK-MB), aspartate transaminase (AST), lactate dehydrogenase (LDH), and other serum cardiac biomarkers Troponin-I activities, oxidative stress biomarkers, malondialdehyde(MDA), Nuclear factor-kappa B (NF-KB), while it decreased Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), Nuclear factor erythroid-2-related factor 2 (Nfe212), mitochondrial transcriptional factor A (mt TFA), mitochondrial DNA copy number and glutathione system parameters. However, Astaxanthin decreased the activities of serum AST, LDH, CK-MB, and Troponin I that elevated by ISO. In addition, it increased glutathione peroxidase and reductase activities, total glutathione and reduced GSH content, and GSH/GSSG ratio, mtDNA copy number, PGC-1α expression and Tfam expression that improved mitochondrial biogenesis while it decreased GSSG and MDA contents and NF-KB level in the cardiac tissues. This study indicated that astaxanthin relieved isoproterenol induced myocardial infarction via scavenging free radicals and reducing oxidative damage and apoptosis in cardiac tissue.

Beta-adrenergic agonism protects mitochondrial metabolism in the pancreatectomised rat heart.

The diabetic heart is characterised by functional, morphological and metabolic alterations predisposing it to contractile failure. Chronic sympathetic activation is a feature of the pathogenesis of heart failure, however the type 1 diabetic heart shows desensitisation to ß-adrenergic stimulation. Here, we sought to understand the impact of repeated isoprenaline-mediated ß-stimulation upon cardiac mitochondrial respiratory capacity and substrate metabolism in the 90% pancreatectomy (Px) rat model of type 1 diabetes. We hypothesised these hearts would be relatively protected against the metabolic impact of stress-induced cardiomyopathy. We found that individually both Px and isoprenaline suppressed cardiac mitochondrial respiration, but that this was preserved in Px rats receiving isoprenaline. Px and isoprenaline had contrasting effects on cardiac substrate metabolism, with increased reliance upon cardiac fatty acid oxidation capacity and altered ketone metabolism in the hearts of Px rats, but enhanced capacity for glucose uptake and metabolism in isoprenaline-treated rats. Moreover, Px rats were protected against isoprenaline-induced mortality, whilst isoprenaline elevated cGMP and protected myocardial energetic status in Px rat hearts. Our work suggests that adrenergic stimulation may be protective in the type 1 diabetic heart, and underlines the importance of studying pathological features in combination when modeling complex disease in rodents.

Investigation of the cardioprotective effects of Momordica charantia in the isoproterenol-induced myocardial infarction model in rats.

BACKGROUND: Cardiovascular diseases are the most prevalent and primary cause of death globally, and the most deadly and dangerous of these diseases is myocardial infarction (MI), commonly known as heart attack, which develops due to insufficient coronary artery flow and causes irreversible myocardial cell damage. This study aimed to investigate the cardioprotective effects of Momordica charantia (MC), known for its antioxidant and anti-inflammatory properties, in an experimental acute MI model induced by isoprenaline (ISO) in rats. METHODS: In the study, forty-nine male Wistar rats were split up into 7 groups as control (CONT), Glycerin (GLCN), isoprenaline (ISO), 500 mg/kg MC (MC500), isoprenaline+100 mg/kg MC (ISO+MC100), isoprenaline+250 mg/kg MC (ISO+MC250), isoprenaline+500 mg/kg MC (ISO+MC500). Substances were administered to the groups for 30 days. Isoprenaline (85 mg/kg) was administered by subcutaneous injection on the last two days of the study (days of the 29 and 30). Electrocardiogram (ECG) recording and collecting blood samples of the animals were performed 24 hours after the last administration of the substances under the anesthesia. Serum IL-6, Nrf2, IL-10, HO-1, TNF-α, CK-MB, cTn-I and CRP levels were determined by the ELISA method. RESULTS: Compared to the ISO group, levels of CK-MB, HO-1, TNF-α, CRP, IL-6 and cTn-I were found statistically lower in MC-administered groups (p<0.05). In addition, MC restored ISO-induced abnormal ECG changes to normal levels. CONCLUSION: In conclusion, ECG findings, proinflammatory, anti-inflammatory, antioxidative and cardiac biomarkers suggest that MC may have cardioprotective properties.

Effects of D-Allose on experimental cardiac hypertrophy.

The hallmark of pathological cardiac hypertrophy is the decline in myocardial contractility caused by an energy deficit resulting from metabolic abnormalities, particularly those related to glucose metabolism. Here, we aim to explore whether D-Allose, a rare sugar that utilizes the same transporters as glucose, may restore metabolic equilibrium and reverse cardiac hypertrophy. Isolated neonatal rat cardiomyocytes were stimulated with phenylephrine and treated with D-Allose simultaneously for 48 h. D-Allose treatment resulted in a pronounced reduction in cardiomyocyte size and cardiac remodelling markers accompanied with a dramatic reduction in the level of intracellular glucose in phenylephrine-stimulated cells. The metabolic flux analysis provided further insights revealing that D-Allose exerted a remarkable inhibition of glycolysis as well as glycolytic capacity. Furthermore, in mice subjected to a 14-day continuous infusion of isoproterenol (ISO) to induce cardiac hypertrophy, D-Allose treatment via drinking water notably reduced ISO-induced cardiac hypertrophy and remodelling markers, with minimal effects on ventricular wall thickness observed in echocardiographic analyses. These findings indicate that D-Allose has the ability to attenuate the progression of cardiomyocyte hypertrophy by decreasing intracellular glucose flux and inhibiting glycolysis.

Cinnamaldehyde activates AMPK/PGC-1α pathway via targeting GRK2 to ameliorate heart failure.

BACKGROUND: According to recent research, treating heart failure (HF) by inhibiting G protein-coupled receptor kinase 2 (GRK2) to improve myocardial energy metabolism has been identified as a potential approach. Cinnamaldehyde (CIN), a phenylpropyl aldehyde compound, has been demonstrated to exhibit beneficial effects in cardiovascular diseases. However, whether CIN inhibits GRK2 to ameliorate myocardial energy metabolism in HF is still unclear. PURPOSE: This study examines the effects of CIN on GRK2 and myocardial energy metabolism to elucidate its underlying mechanism to treat HF. METHODS: The isoproterenol (ISO) induced HF model in vivo and in vitro were constructed using Sprague-Dawley (SD) rats and primary neonatal rat cardiomyocytes (NRCMs). Based on this, the effects of CIN on myocardial energy metabolism and GRK2 were investigated. Additionally, validation experiments were conducted after interfering and over-expressing GRK2 in ISO-induced NRCMs to verify the regulatory effect of CIN on GRK2. Furthermore, binding capacity between GRK2 and CIN was explored by Cellular Thermal Shift Assay (CETSA) and Microscale Thermophoresis (MST). RESULTS: In vivo and in vitro, CIN significantly improved HF as demonstrated by reversing abnormal changes in myocardial injury markers, inhibiting myocardial hypertrophy and decreasing myocardial fibrosis. Additionally, CIN promoted myocardial fatty acid metabolism to ameliorate myocardial energy metabolism disorder by activating AMPK/PGC-1α signaling pathway. Moreover, CIN reversed the inhibition of myocardial fatty acid metabolism and AMPK/PGC-1α signaling pathway by GRK2 over-expression in ISO-induced NRCMs. Meanwhile, CIN had no better impact on the stimulation of cardiac fatty acid metabolism and the AMPK/PGC-1α signaling pathway in ISO-induced NRCMs when GRK2 was disrupted. Noticeably, CETSA and MST confirmed that CIN binds to GRK2 directly. The binding of CIN and GRK2 promoted the ubiquitination degradation of GRK2 mediated by murine double mimute 2. CONCLUSION: This study demonstrates that CIN exerts a protective intervention in HF by targeting GRK2 and promoting its ubiquitination degradation to activate AMPK/PGC-1α signaling pathway, ultimately improving myocardial fatty acid metabolism.

Baricitinib alleviates cardiac fibrosis and inflammation induced by chronic sympathetic activation.

Cardiac fibrosis is characterized by the over-proliferation, over-transdifferentiation and over-deposition of extracellular matrix (ECM) of cardiac fibroblasts (CFs). Cardiac sympathetic activation is one of the leading causes of myocardial fibrosis. Meanwhile, cardiac fibrosis is often together with cardiac inflammation, which accelerates fibrosis by mediating inflammatory cytokines secretion. Recently, the Janus kinase/signal transducer and activator of transcription (JAK/STAT3) signaling pathway has been confirmed by its vital role during the progression of cardiac fibrosis. Thus, JAK/STAT3 signaling pathway is thought to be a potential therapeutic target for cardiac fibrosis. Baricitinib (BR), a novel JAK1/2 inhibitor, has been reported excellent effects of anti-fibrosis in multiple fibrotic diseases. However, little is known about whether and how BR ameliorates cardiac fibrosis caused by chronic sympathetic activation. Isoproterenol (ISO), a ß-Adrenergic receptor (ß-AR) nonselective agonist, was used to modulate chronic sympathetic activation in mice. As expected, our results proved that BR ameliorated ISO-induced cardiac dysfunction. Meanwhile, BR attenuated ISO-induced cardiac fibrosis and cardiac inflammation in mice. Moreover, BR also inhibited ISO-induced cardiac fibroblasts activation and macrophages pro-inflammatory secretion. As for mechanism studies, BR reduced ISO-induced cardiac fibroblasts by JAK2/STAT3 and PI3K/Akt signaling, while reduced ISO-induced macrophages pro-inflammatory secretion by JAK1/STAT3 and NF-κB signaling. In summary, BR alleviates cardiac fibrosis and inflammation caused by chronic sympathetic activation. The underlying mechanism involves BR-mediated suppression of JAK1/2/STAT3, PI3K/Akt and NF-κB signaling.