Induced Heart Failure Research Articles

Evaluation of Hematological, inflamatory and Histopathological Changes in Doxorubicin Induced Heart Failure Rats Receiving Sardinella maderensis Oil as Protective Measure

Objective: Current studies suggest that fish oil may have cardioprotective effects. The objective of this study was to evaluate the hematological, inflammatory markers, and histopathological changes in doxorubicin induced heart failure rats receiving Sardinella maderensis fish oil. Materials and Methods: Sardine fish was purchased from Congelcam, and oil extracted using the standard Bligh and Dyer protocol. The oil quality indices (acide value, iodine value, peroxide value, anisidine value and Totox value) were measured using standard AOAC methods To test the biochemical activities of the oil, 36 male wistar rats weighing between 150g to 180g were purchased. The animals had food and water ad libitum throughout the experimental period (28 days). They were divided into six groups of six rats each: G1 (normal group), G2 (negative control), G3 (Positive control; gemfibrozil 100 mg/kg), G4 (Test group I; fish oil 250 mg/kg), G5 (Test group II; fish oil 500 mg/kg), G6 (Test Group III; fish oil 1000 mg/kg). G1 rats received distilled water, G2 to G6 rats received DOX 2.5mg/kg on days 13, 16, 19, 22, 25, 28 for a cumulative dose of 15 mg/kg. On the 29th day, the rats were anaesthetized, sacrificed and blood samples collected to assess serum cytokine levels and hematological parameters. Organs were also collected for histopathological analysis. Results: Results showed that DOX administration significantly decreased (p<0.001) hematological parameters WBC, RBC, Hb, hematocrit, platelets, monocytes, granulocytes, MCV, MCH and MCHC in the negative group compared to the normal group. Serum levels of inflammatory cytokines increased significantly (p<0.001) in the negative group TNF-α (352.7), INF-δ (364.17), IL-1β (323.91), IL-6 (479.88) and IL-10 (397.91) compared to the normal group. However, pre-treatment with fish oil in the test groups significantly increased (p<0.05) hematological parameters (WBC, RBC, Hb, hematocrit, platelets, monocytes, granulocytes, MCV, MCH) compared to the negative group. Serum levels of inflammatory cytokines in the test groups decreased significantly (p<0.05) especially those in test group III; TNF-α (184.85), INF-δ (145.15), IL-1β (152.81), IL-6 (321.58) and IL-10 (230.33). Histological lesions identified in the heart, liver, and kidney tissues of the negative control rats were significantly attenuated in all the test groups receiving fish oil. Conlusion: Animals receiving fish had improved hematological parameters, decreased levels of inflammatory cytokines and improved organ histology. These findings demonstrate therefore that Sardinella maderensis oil could have cardio-protective effects on human health.

Abstract 4143219: Pressure-Volume Analysis by Three-Dimensional Echocardiography: A Novel Method to Estimate Left Ventricular Efficiency

Background: Left ventricular (LV) efficiency is a key pathophysiological marker in heart failure (HF). LV pressure curve estimation and three-dimensional (3D) volumes via echocardiography allows for non-invasive pressure-volume (PV) analysis and calculation of an index of efficiency (Figure 1). Aim: Validate efficiency index by 3D echocardiography by comparing it to invasive measurements and efficiency derived from Positron Emission Tomography (PET) metabolism. Methods: Two experimental models were utilized - one with canines (n=21) and another with sheep (n=12). In canines, echocardiography provided 3D LV volumes and valve event timings. The pressure curve was estimated by adjusting the time axis of a reference pressure curve to the valve events and its amplitude to measured peak LV pressure, which in clinical practice would be approximated as systolic brachial cuff pressure. Invasive pressure was measured by micromanometer and volume by subendocardial piezoelectric crystals. Non-invasive and invasive efficiency indices, calculated as the ratio of stroke work to total mechanical energy (Figure 1), were compared during baseline, right ventricular pacing, aortic constriction and dobutamine infusion. Twelve sheep implanted with a pacemaker underwent 8 weeks of rapid dyssynchronous DDD pacing to induce dilated HF. LV efficiency index was calculated as in Figure 1, using measurements from a PV-catheter calibrated to end-diastolic volume by cardiac MRI, and compared to efficiency calculated as stroke work divided by total LV glucose metabolism via PET/CT. Recordings were performed during AAI and DDD pacing, at baseline (n=3) and following 8 weeks pacing-induced HF (n=12). Results: In canines, non-invasive and invasive efficiency indices showed excellent agreement (r=0.95, p<0.0001; mean difference 0.4%, SD 3.4%) (Figure 2). In sheep, the efficiency index showed similar decline compared to efficiency by PET/CT after induction of HF and after switching from AAI to DDD pacing (p<0.05 for all interventions). Overall correlation between the methods was moderate (r=0.67, p=0.0001) but excellent in animals with longitudinal data (r=0.89, p=0.0001) (Figure 3). Conclusions: Efficiency index by 3D echocardiography is accurate and reflects changes in efficiency measured by PET/CT. It may thus be of interest for clinical use.

Abstract 4115947: Empagliflozin Inhibits the Mobilization of CCR2+ Monocyte-Derived Macrophages by Reducing CCL2 Expression in Fibroblasts and Slows the Progression of Heart Failure After Pressure Overload.

Background: The positive effects of sodium glucose co-transporter-2 (SGLT2) inhibitors on reducing cardiovascular mortality and hospitalizations due to heart failure have been well established. Although numerous theories propose explanations for the cardioprotective actions of SGLT2 inhibitors, these hypotheses primarily rely on initial findings and require further validation. Studies have shown that immune cells, particularly macrophages marked by C-C chemokine receptor type 2 (CCR2), contribute to the progression of heart failure by infiltrating the myocardium and inducing detrimental structural changes following myocardial infarction or pressure overload. Purpose: This study aims to investigate whether SGLT2 inhibitors can mitigate heart damage by inhibiting the migration of CCR2+ monocyte-derived macrophages. Methods: In this experiment, male B6 mice were subjected to transverse aortic constriction (TAC) to induce heart failure. Two weeks post-TAC, with heart function confirmed as equal across all groups by echocardiography, one group began receiving daily oral doses of empagliflozin, while another served as the control. At four weeks post-TAC, cardiac function was reassessed. The animals were then euthanized, and their hearts were analyzed using flow cytometry, staining, and qPCR to evaluate heart failure and the involvement of immune cells. Additionally, isolated cardiac fibroblasts were subjected to cyclic stretching to mimic post-TAC mechanical stress. Results: Treatment with empagliflozin resulted in improved cardiac function and reduced congestion in the heart and lungs, indicating alleviation of heart failure. The treatment notably decreased myocardial fibrosis, evident from Picrosirius-red staining and reduced expression of fibrosis-related mRNA. Importantly, empagliflozin specifically reduced the number of CCR2-positive macrophages in the heart, without affecting other types of immune cells. In cardiac fibroblasts that underwent cyclic stretching, empagliflozin pre-treatment diminished the expression of C-C motif chemokine ligand 2 (CCL2), the ligand for CCR2. Conclusion: Empagliflozin’s ability to suppress CCL2 expression in fibroblasts and curtail the recruitment of CCR2+ macrophages may represent a potential strategy to decelerate heart failure progression. These findings advance our understanding of the cardioprotective mechanisms of SGLT2 inhibitors and propose novel therapeutic avenues for heart failure management.

Intrapericardial Administration of Human Pericardial Fluid Cells Improves Cardiac Functions in Rats with Heart Failure.

Heart failure (HF) is still the main cause of mortality worldwide. This study investigated the characteristics of human pericardial fluid-derived cells (hPFCs) and their effects in treating doxorubicin (DOX)-induced HF rats through intrapericardial injection. hPFCs were isolated from patients who underwent heart transplantation (N = 5). These cells that primarily expressed SCA-1, NANOG, and mesenchymal markers, CD90, CD105, and CD73, were able to form adipocytes, osteoblasts, and cardiomyocytes in vitro. Passage 3 hPFCs (2.5 × 105 cells/heart) were injected into the pericardial cavity of the DOX-injured rat hearts, significantly improving cardiac functions after 4 weeks. The tracked and engrafted red fluorescent protein-tagged hPFCs coexpressed cardiac troponin T and connexin 43 after 4 weeks in the host myocardium. This observation was also coupled with a significant reduction in cardiac fibrosis following hPFC treatment (P < 0.0001 vs. untreated). The elevated inflammatory cytokines interleukin (IL)-6, IL-10, and tumor necrosis factor-α in the DOX-treated hearts were found to be significantly reduced (P < 0.001 vs. untreated), while the regional proangiogenic vascular endothelial growth factor A (VEGFA) level was increased in the hPFC-treated group after 4 weeks (P < 0.05 vs. untreated). hPFCs possess stem cell characteristics and can improve the cardiac functions of DOX-induced HF rats after 4 weeks through pericardial administration. The improvements were attributed to a significant reduction in cardiac fibrosis, inflammation, and elevated regional proangiogenesis factor VEGFA, with evidence of cellular engraftment and differentiation in the host myocardium.

Yiqi Fumai Lyophilized injection protects cardiac contractility in a rat model of heart failure with reduced ejection fraction by modulating SERCA2

BackgroundYiqi Fumai Lyophilized Injection (YQFM) is a plant-derived preparation that shows protective effects against cardiac dysfunction in both human and animal models. In heart failure (HF), proteins involved in Ca2+ regulation, such as sarcoplasmic/endoplasmic reticulum Ca2+ transporting protein 2 (SERCA2) and cardiac ryanodine receptor 2 (RyR2), are dysfunctional. Compensation for the malfunction of these proteins is considered a practical option for restoring heart function. MethodsCoronary artery ligation was used to induce heart failure with reduced ejection fraction (HFrEF) in Sprague-Dawley rats. YQFM was administered via intravenous injection for two weeks. Cardiac contractility was evaluated using echocardiography. Hematoxylin and Eosin (H&E) staining, Masson's trichrome staining, western blotting, and immunohistochemical analysis were performed to evaluate myocardial damage and investigate the underlying molecular mechanisms. In vitro, H9C2 cells were subjected to oxygen and glucose deprivation. Western blotting and immunofluorescence staining were used to assess the expression of key Ca2+-handling proteins in the H9C2 cell models. ResultsTwenty-five compounds, mainly ginsenosides, were identified in YQFM. In rats with HFrEF, treatment with YQFM or metoprolol prevents deterioration of cardiac contractility. YQFM caused a patchy delay in the downregulation of SERCA2 in the myocardium, resulting in reduced dilation of the left and right ventricles, thereby preventing left ventricular remodeling. In H9C2 cell models, our results demonstrated that YQFM partially prevented defects in SERCA2. ConclusionOur study demonstrated that YQFM may function as a positive cardiac contractility modulator and therapeutic agent for cardiac protection by restoring SERCA2 expression in cardiomyocytes in HF after myocardial infarction (MI).

Beneficial effects of the SGLT2 inhibition on oxidative skeletal muscle in infarcted rats

Abstract Introduction Metabolic, morphological, and biochemical changes in skeletal muscle are common in chronic heart failure patients. Despite the cardioprotective effects of sodium-glucose co-transporter 2 (SGLT2) inhibition in heart failure, the impact of this drug on skeletal muscle remains poorly understood. This study investigated the effects of SGLT2 inhibitor empagliflozin (EMPA) on the soleus muscle of rats with myocardial infarction (MI)-induced heart failure. Methods One week after MI induction, male Wistar rats were divided into Sham (n=10), Sham+EMPA (n=12), MI (n=10) and MI+EMPA (n=09) groups. EMPA was added to rat chow (5 mg/kg/day) for 12 weeks. Cardiac remodeling was evaluated by echocardiogram. Enzymatic activity and oxidative stress marker concentrations were assessed by spectrophotometry; protein expression was evaluated by Western blotting. After histological analysis of the left ventricle (LV), only rats with MI greater than 35% of total LV area were included in the study. Statistical analysis: ANOVA and Tukey or Kruskal–Wallis and Dunn and t test; p&amp;lt;0.05. Results Infarction size did not differ between groups. Infarcted groups had larger LV systolic and diastolic diameters, LV diastolic area (Sham 47±7.1; Sham+EMPA 48±4.5; MI 100±16.1*; MI+EMPA 85±10.1#† mm2; p&amp;lt;0.05: * vs Sham; # vs Sham+EMPA; † vs MI), and left atrial diameter (Sham 5.62±0.2; Sham+EMPA 5.65±0.3; MI 7.69±1.3*; MI+EMPA 6.85±0.9#† mm; p&amp;lt;0.05: * vs Sham; # vs Sham+EMPA; † vs MI); and lower LV posterior wall shortening velocity and ejection fraction than control groups. Echocardiographic changes were attenuated in MI+EMPA compared to MI. Other results are shown in Picture 1. Conclusion SGLT2 inhibitor empagliflozin attenuates infarction-induced cardiac remodeling in rats. Empagliflozin prevents increase in oxidative stress, modulates protein turnover by IGF-1 pathway, and attenuates morphological and biochemical changes in the soleus muscle of infarcted rats.

ATM: a protein involved in glucose and lipid metabolism in the heart

Abstract Backround Post-mitotic cells, such as neurons and cardiomyocytes, cannot repair DNA lesions with DNA replication and rely for their survival on efficient sensors and effectors that orchestrate the DNA damage response (DDR). The Ataxia Telangiectasia Mutated (ATM) protein kinase is the most important sensor of oxidative stress and the DNA damage response (DDR) and is implicated in cellular metabolism. It is believed that while transient DNA damage and DDR can temporarily improve cardiovascular function, persistent activation of DDR (and ATM) might promote the onset and development of heart failure (HF). Purpose We hypothesised that ATM might control and regulate energy metabolism in the heart under stress to promote DNA repair. Methods We analyzed the effects of ATM inactivation on cardiomyocyte hypertrophy, cardiac function, DDR and metabolism in hearts from wild-type (Atm+/+) or Atm-mutated (Atm-/-) mice under sham conditions or after pressure overload by transverse aortic constriction (TAC). Results ATM inactivation in Atm-/- mice induced cardiomyocyte hypertrophy, fetal gene expression re-activation and a specific metabolomic signature in the heart, characterized by significant accumulation of pyruvate, branched chain amino-acids, short-medium acyl-carnitines and metabolites of tricarboxylic acid cycle. The levels of the glycolytic enzymes, hexokinase-2 (HK2) and phosphofructokinase (PFK), were elevated. pyruvate was trapped in the cytosol because mitochondrial carriers were suppressed and the enzymes that process pyruvate were dysregulated. Because of pyruvate metabolic block, fatty acids oxidation was inefficient and resulted in the accumulation of acyl-carnitines and insulin resistance. These metabolic changes were amplified by TAC, which rapidly induced heart failure in Atm-/- mice. ATM inactivation also increased basal and TAC-induced genomic stress in cardiomyocytes, as shown by the levels of p-γ-H2AX, 8-oxodG glycosylase (OGG1/2) and apurinic site nuclease (APE1). These results prove that ATM rewires the metabolism of cardiac cells by inducing glycolysis and fatty acids oxidation. ATM stimulates glycolysis to repair DNA lesions and protect the heart against stress-induced dysfunction. The metabolic block due to ATM inactivation accelerates heart failure. Conclusions Our data suggest that ATM favors the metabolic flexibility of the heart by stimulating glucose entry and balancing glucose catabolism with fatty acid oxidation, thus preventing mechanical stress-induced cardiac systolic dysfunction.

Deletion of mitochondrial DNA methyltransferase 1 contributes the development of murine heart failure under pressure overloaded

Abstract Background Mitochondrial DNA (mitDNA) has similarities to bacterial DNA, which contains inflammatogenic unmethylated CpG motifs. We found that mitDNA that escapes from autophagy causes inflammatory response and heart failure under pressure overload. DNA methyltransferase 1 (DNMT1) maintains methylation patterns in somatic cells. Deletion of DNMT1 results in embryonic lethality in mice and mitotic catastrophe in cultured cells. Additional possible translational start sites (ATG1, ATG2) are located upstream of the commonly accepted nuclear DNMT1 translational start site (ATG3) and there is a conserved mitochondrial translocation signal sequence between ATG1 and ATG3. The role of mitochondrial DNMT1 in the development of heart failure remains to be elucidated. Purpose The purpose of this study is to examine the in vivo role of mitochondrial DNMT1 in the heart under pressure overload. Methods We generated HA-tagged DNMT1 constructs, 1) starting from ATG1 (termed as whole) 2) from ATG3 (nuclear) and 3) from ATG3 and mutated in the nuclear translocation sequence (mitochondrial) and transfected HEK293 cells with the constructs. Localization of HA-tagged proteins was assessed by immunocytochemistry. We also generated mitochondrial DNMT1-deficient mice by inserting mutations into the ATG1 and ATG2. The mice were subjected to pressure overload by means of transverse aortic constriction (TAC) to induce heart failure. Cardiac remodelling was assessed by echocardiography as well as histological analyses 4 weeks after operation. Results Whole, nuclear and mitochondrial DMNT1 translocated to both mitochondria and nuclei, only nucleus and only mitochondria, respectively. Mitochondrial DNMT1-deficient mice were born at Mendelian frequency and grew to adulthood. Those showed no cardiac phenotypes under baseline conditions. However, the mice exhibited severe systolic dysfunction, indicated by left ventricular fractional shortening, 2 weeks after surgery compared with control littermates (control littermates 47.9% versus Mitochondrial DNMT1-deficient mice 32.3%, p&amp;lt;0.05). Intermuscular cell infiltration was observed in TAC-operated mitochondrial DNMT1-deficient hearts. Conclusions Mitochondrial DNA methyltransferase 1 plays a protective role in failing hearts and mitDNA methylation might be a therapeutic target to treat patients with heart failure.

Prognostic impact of myocarditis as aetiology compared with dilated cardiomyopathy and ischaemic heart disease in heart failure

Abstract Background A subgroup of myocarditis can lead to heart failure. However, whether prognosis of myocarditis-induced heart failure differs from other heart failure remains largely unknown. Aim This study aimed to investigate the prognostic impact of myocarditis induced heart failure compared with heart failure with dilated cardiomyopathy and ischaemic heart disease as causes respectively in the overall population and a propensity score-matched cohort, based on patient-level data from the Swedish Heart Failure Registry (SwedeHF). Methods Patients with heart failure (HF) were enrolled from the SwedeHF (2003-2020) linked with the National Patient Register, and the Swedish Cause of Death Register. Endpoints were all-cause mortality, cardiovascular death, and hospital re-admissions, followed up from the index date until censoring or event. Results Of 54416 patients identified through the SwedeHF with HF, 418 hade myocarditis as aetiology (MC-HF), 6,871 with dilated cardiomyopathy (DCM-HF) and 47127 with ischemic heart diseases (IHD-HF). In general patients with MC-HF have shorter disease duration and less comorbidities compared with DCM-HF and IHD-HF, but older than DCM-HF and younger than IHD-HF. Compared with DCM-HF, MC-HF are associated with 29% higher risk for all cause mortality [(1.29 (1.07 - 1.55), p=0.0079] and 40% higher risk for cardiovascular death [ 1.40 (1.09 - 1.80), p=0.0088], and 19 % higher risk for heart failure rehospitalization [1.19 (1.03 - 1.37), p=0.018] and even higher risk by censoring within one-year . However, compared with IHD-HF, patients with MC-HF have similar risk for all cause mortality [0.95 (0.80 - 1.13), p=0.54], cardiovascular death [0.95 (0.75 - 1.20), p=0.65], and heart failure rehospitalization [0.93 (0.81 - 1.06), p=0.29]. Similar results were obtained from a propensity 1:2 matched cohort. No significant interactions were found regardless of age (&amp;lt; and &amp;lt; 70 years) , sex, LVEF (≥50%, 40-49%, 30-39% and &amp;lt; 30%) for all cause mortality comparing MC-HF vs DCM-HF, and MC-HF vs IHD-HF. Conclusion Patients with myocarditis-induced heart failure have worse outcome than heart failure due to dilated cardiomyopathy, with even higher risk during one year. This finding highlights the importance of early and more effective customized management of patients with myocarditis in particular those with high risk to develope heart failure.

Loss of NAT10 Reduces the Translation of Kmt5a mRNA Through ac4C Modification in Cardiomyocytes and Induces Heart Failure.

In the past decade, the biological functions of various RNA modifications in mammals have been uncovered. N4-acetylcytidine (ac4C), a highly conserved RNA modification, has been implicated in human diseases. Despite this, the involvement of RNA ac4C modification in cardiac physiology and pathology remains incompletely understood. NAT10 (N-acetyltransferase 10) stands as the sole acetyltransferase known to catalyze RNA ac4C modification. This study aims to explore the role of NAT10 and ac4C modification in cardiac physiology and pathology. Cardiac-specific knockout of NAT10, leading to reduced RNA ac4C modification, during both neonatal and adult stages resulted in severe heart failure. NAT10 deficiency induced cardiomyocyte apoptosis, a crucial step in heart failure pathogenesis, supported by invitro data. Activation of the p53 signaling pathway was closely associated with enhanced apoptosis in NAT10-deficient cardiomyocytes. As ac4C modification on mRNA influences translational efficiency, we employed ribosome footprints coupled with RNA sequencing to explore genome-wide translational efficiency changes caused by NAT10 deficiency. We identified and validated that the translational efficiency of Kmt5a was suppressed in NAT10 knockout hearts due to reduced ac4C modification on its mRNA. This finding was consistent with the observation that Kmt5a protein levels were reduced in heart failure despite unchanged mRNA expression. Knockdown of Kmt5a in cardiomyocytes recapitulated the phenotype of NAT10 deficiency, including increased cardiomyocyte apoptosis and activated p53 signaling. Finally, overexpression of Kmt5a rescued cardiomyocyte apoptosis and p53 activation induced by NAT10 inhibition. Our study highlights the significance of NAT10 in cardiomyocyte physiology, demonstrating that NAT10 loss is sufficient to induce cardiomyocyte apoptosis and heart failure. NAT10 regulates the translational efficiency of Kmt5a, a key mediator, through mRNA ac4C modification during heart failure.

Novel Role of BK-Channel Activation in Ameliorating Cardiac Fibrosis in the Ischemia-Reperfusion (IR)-Induced Heart Failure Mouse Model

Novel Role of BK-Channel Activation in Ameliorating Cardiac Fibrosis in the Ischemia-Reperfusion (IR)-Induced Heart Failure Mouse Model

Comparison of chemical composition between imitation wild and transplanted Astragali Radix and their therapeutic effects on heart failure

Ethnopharmacological relevanceAstragali Radix (AR) is a traditional Chinese herbal medicine, which has been widely used on treating chronic heart failure (CHF) in clinical practice. Two main types of AR in the market are the imitation wild AR (5YAR) and transplanted AR (2YAR). It remains unclear whether there are variations in the anti-heart failure effects of AR with different growth years. Further research is required to explore the material composition and mechanisms of AR in combating heart failure. Aim of the studyThe aim of the study was to compare the main chemical composition content and the protective effects of 2YAR and 5YAR on heart failure. Materials and methodsEthanol extracts of 2YAR and 5YAR were prepared, and chemical composition analysis was conducted. C57BL/6 mice were subcutaneously injected with ISO to induce heart failure (HF) and were administrated with a corresponding dose of the extracts of 2YAR and 5YAR by gavage for 28 days. Cardiac function was evaluated using echocardiography. The serum levels of enzymes related to myocardial injury, oxidative stress, and inflammation were detected. The left ventricle was excised for hematoxylin-eosin, Masson, Sirius Red, wheat germ agglutinin, and TUNEL staining. Electron microscopy examination of mitochondrial structure in myocardial cells. Protein expression of monocarboxylate transporter 4 (MCT4), Peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), phosphorylated AMP-activated protein kinase (p-AMPK), phosphorylated serine/threonine protein kinase (p-AKT), and phosphorylated insulin receptor substrates 1 (p-IRS-1) were detected by immunohistochemistry and Western blot. ResultsThe content of saponins and flavonoids in 5YAR was higher than that in the 2YAR. However, the content of polysaccharides in 5YAR is lower than in 2YAR. The treatment of 2YAR and 5YAR daily for 28 days prevented ISO-induced myocardial damage, including the decrease in serum cardiac enzymes and cardiomyocyte apoptotic index, and improvement in heart function and mitochondrial structure. Additionally, 2YAR and 5YAR reduced serum inflammatory factors and myocardial fibrosis levels. Treatment with 2YAR and 5YAR also decreased MCT4 expression and enhanced PGC-1α, p-AKT, p-AMPK, and p-IRS-1 expression in heart tissues. ConclusionsThe 5YAR was better than 2YAR in anti-heart failure, which may be related to the increase in saponins and flavonoids content. AR exerts anti-heart failure effect by improving mitochondrial function and ameliorating cardiac insulin resistance through activation of the AMPK/PGC1α and IRS/AKT pathways.

The protective effect of Ghrelin peptide on doxorubicin hydrochloride induced heart failure in rats

BackgroundTo investigate the protective effect and mechanism of Ghrelin on Doxorubicin (Dox) hydrochloride induced heart failure (HF) and myocardial injury in rats.Methods45 rats were randomly divided into control group, HF group and Ghrelin group. Dox hydrochloride was injected intraperitoneally to establish the model of HF in rats of HF group and Ghrelin group. Rats in the Ghrelin group were given intraperitoneal injection of Ghrelin twice a day, and rats in the HF group and control group were given equal volume of normal saline for a total of 6 weeks. The changes of echocardiography, cardiac hemodynamics, myocardial histology and plasma inflammatory factors were observed.ResultsAfter the Ghrelin intervention, compared with the HF group, the left ventricular end-diastolic diameter (LVDD) and left ventricular end-systolic diameter (LVSD) in the Ghrelin group was markedly reduced (P < 0.05), and left ventricular ejection fraction (LVEF) was significantly increased (P < 0.05). Compared with HF group, the left ventricular systolic pressure (LVSP), maximum rate of increase in left ventricular pressure (+ dP/dtmax) and maximum rate of decrease in left ventricular pressure (− dP/dtmax) of Ghrelin group was remarkedly increased (P < 0.05), left ventricular diastolic pressure (LVDP) decreased (P < 0.05). In the Ghrelin group, the degree and extent of cardiomyocyte degeneration and necrosis were remarkedly reduced compared with the HF group. The levels of TNF-α and iNOS in Ghrelin group were notably lower than those in HF group (P < 0.05), the IL-10 level increased markedly (P < 0.05).ConclusionGhrelin may reduce Dox-induced myocardial injury and improve cardiac function in rats by regulating inflammation and oxidative stress.

Abstract P396: A Selective Agonist of the Beta 2 Retinoic Acid Receptor Reduces Necrosis, Lipid Peroxidation, and Oxidative Stress in Doxorubicin-induced Cardiotoxicity

Objective: Doxorubicin (Doxo) is used as an antiproliferative agent to treat various cancers. However, a significant limitation of Doxo is cardiotoxicity, that can induce heart failure in patients. Mounting evidence indicates that an increased generation of reactive oxygen species (ROS), lipid peroxidation, and necrosis, are major causes of Doxo-induced heart failure. Recently, we reported that a highly selective and potent agonist of the b2 retinoic acid receptor (RARb2), improved cardiac dysfunction in mice model of myocardial infarction by inhibiting oxidative stress. In this study we investigated cardioprotective effects of RARb2 stimulation on Doxo-induced heart failure. Methods: We performed in vitro and in vivo experiments on an established murine model of Doxo-induced heart failure. Necrosis, oxidative stress, and lipid peroxidation were evaluated, assessing both the prevention and the rescue capacities of RARb2 stimulation. Results: An increased ROS production both at the mitochondrial and cellular level was observed in cardiomyocytes isolated from Doxo-treated mice. RARb2 stimulation significantly attenuated Doxo-induced ROS production. In addition, this treatment mitigated lipid peroxidation induced by Doxo in the left ventricle, marked by 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). RARb2 stimulation also mitigated the increased expression of High Mobility Group Box 1 (HMGB1), a necrosis marker, in the heart and in the serum of Doxo-treated mice. Conclusion: Our data demonstrate that RARb2 stimulation can attenuate necrosis, lipid peroxidation, and ROS production in a mouse model of Doxo cardiotoxicity.

The benefits and protective effects of copper nanoparticles green-formulated by Foeniculum vulgare extract on rats with heart failure following myocardial infarction

This study explores the potential of green-synthesized copper nanoparticles (Cu@Fv NPs) derived from fennel (Foeniculum vulgare) seeds for treating heart failure after a myocardial infarction. Fennel boasts a rich history in traditional medicine, and this research leverages its properties for a novel approach to nanomedicine. We successfully synthesized Cu@Fv NPs with well-defined spherical morphology and an average size of 48.46 nm, as confirmed by advanced characterization techniques. In vivo studies on rats with induced heart failure demonstrated the protective effects of Cu@Fv NPs. Notably, oral administration of Cu@Fv NPs at specific doses significantly reduced the lung/body weight ratio, inhibited neurohormonal activation, and led to a remarkable decrease in infarct size. Additionally, Cu@Fv NPs treatment resulted in improved cardiac function, evidenced by increased +/−dp/dt(max) and decreased LVEDP. These findings unveil the promising potential of Cu@Fv NPs as a biocompatible and potentially superior therapeutic strategy for managing heart failure post-myocardial infarction. This green synthesis method offers a sustainable and eco-friendly alternative to conventional nanoparticle production, paving the way for further exploration in nanomedicine.

A new animal model of cardiorenal syndrome could be established by inducing heart failure through coronary artery ligation in spontaneously hypertensive rats

In rats with unilateral nephrectomy and cardiac dysfunction, renal function deteriorates at an accelerated rate, as evidenced by increased proteinuria. Whether myocardial infarct-induced heart failure (HF) exacerbates renal injury in hypertensive rats with mild renal injury has not been reported. Rats underwent either coronary ligation or sham surgery. Thirty spontaneously hypertensive rats (SHRs) aged 8 weeks were randomly divided into two groups. Group 1 was the sham group, in which the rats underwent thoracotomy without ligation of the coronary artery. Group 2 underwent coronary artery ligation. The rats in group 2 underwent coronary artery ligation on week 0. The experiment lasted 12 weeks. Urine was collected in metabolic cages over a 24-h period. Urine was collected from the rats 2 days before the end of the experiment, and the ratio of urinary protein to urinary creatinine was measured in the clinical laboratory. All rats were examined by echocardiogram one day before the end of the experiment. On the last day of the experiment, blood was collected and sent to the laboratory for analysis. Hematoxylin–eosin (HE) and periodic acid-Schiff (PAS) staining were performed on heart and kidney sections. The ejection fraction in group 2 was lower than that in group 1 (P < 0.001). The urinary albumin to creatinine ratio in group 2 was greater than that in group 1 (P < 0.001). The urea and creatinine levels in group 1 were significantly lower than those in group 2 (P < 0.01). The levels of brain natriuretic peptide (BNP), neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were greater in the second group than in the first group (P < 0.05). The interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels in group 2 were significantly greater than those in group 1 (P < 0.001). The malondialdehyde (MDA) levels in Group 2 were greater than those in Group 1 (P < 0.01). The glutathione peroxidase (GSH-Px) levels in Group 2 were lower than those in Group 1 (P < 0.05). The level of angiotensin II (AT-II) in group 1 was lower than that in group 2 (P < 0.001). Cardiac dysfunction secondary to myocardial infarction could induce cardiorenal interactions in SHRs. It could be interpreted by the activation of oxidative stress, changes in inflammation and alteration of renin–angiotensin–aldosterone system.

Abstract We130: Novel Role of RBFox1 in Myocardial Infarction Induced Heart Failure

Introduction: Alternative mRNA splicing affects a broad spectrum of cardiac genes during pathological manifestation of heart diseases. Earlier studies from our lab have identified a muscle-specific isoform of RBFox1 to be a key RNA splicing regulator in pressure overload induced heart failure through regulating cardiac transcription factor alternative splicing. However, the physiological impact of RBFox1 in myocardial infarction (MI), and the RBFox1 downstream mRNA alternative splicing events during MI induced cardiac remodeling remains unknown. Goals: To investigate the functional impact of RBFox1 in MI induced cardiac remodeling. Method and Results: At both mRNA and protein levels, we found RBFox1 to be significantly decreased in Sprague-Dawley Rat hearts post MI. To investigate the functional impact of RBFox1 in myocardial infarction, we utilized AAV9 to achieve cardiac specific expression of RBFox1 in rats. Interestingly, expression of RBFox1 prevented cardiac dysfunction post MI characterized by improved cardiac function based on echocardiography. Expression of RBFox1 further reduced hypertrophy, cell death and fibrotic remodeling at both molecular and histological levels post MI. In vitro, expression of RBFox1 is sufficient to prevent hypoxia induced cardiac cell death based on TUNEL staining and cleaved caspase 3 level, while inactivation of RBFox1 promoted cardiac cell death. To further understand the molecular mechanism underlying RBFox1 mediated cardiac protection, we performed RNA-seq analysis to determine the transcriptome changes in vivo. RNA-seq showed insulin secretion, cAMP signaling and muscle contraction pathways to be top significantly changed pathways in RBFox1 expressed rat hearts post MI. Lastly, we have identified Mbnl1 mRNA alternative splicing to be regulated by RBFox1 through promoting a 36bp exon exclusion at the C-terminal of Mbnl1 protein, potentially affecting the function of Mbnl1. Conclusion: In summary, we have identified a previously uncharacterized role of RBFox1 in myocardial infarction injury. RBFox1 expression is critical to preserve cardiac function post MI, potentially through regulating downstream targets alternative splicing, including Mbnl1.

Abstract We143: MED12 Dysregulation Disrupts Transcriptional Programs Leading to Dilated Cardiomyopathy

The Mediator complex serves as a bridge to link transcriptional machinery and transcription factors (TFs) to control transcription, but detailed molecular mechanisms of transcriptional regulation by Mediator are not well-understood. Mediator is comprised of the head, middle, and tail submodules that make up the core Mediator, and the transiently associating kinase submodule. The CDK8 kinase submodule acts to regulate Mediator-RNA Polymerase II interaction. MED12 is an essential Mediator component within the kinase submodule and is required for CDK8 kinase activity. In aging models, dysregulated levels of Med12 mRNA are detected in both atria and ventricles by qRT-PCR. MED12 protein levels are also increased in human heart failure biopsies and in the mouse heart after transverse aortic constriction (TAC)-induced heart failure[KB1] . To test the hypothesis that increased levels of MED12 contribute to development of heart failure we generated cardiac-specific Med12 transgenic mice (cTg) by driving increased MED12 expression in cardiomyocytes using the αMHC promoter. Med12 overexpression leads to a progressive decrease in fractional shortening by serial echocardiography. Decreased cardiac function was accompanied by increased cardiac chamber size and dilation, without cardiac fibrosis. RNA sequencing of cardiomyocytes from cTg and control mice revealed that increased levels of MED12 leads to early changes in gene expression programs. Using ingenuity pathway analysis we identified MED12-regulated gene programs including those involved in calcium cycling. MED12 is a transcriptional regulator but does not directly bind DNA. To determine how MED12 regulates gene expression we screened for TFs that interact with MED12. We performed immunoprecipitation of MED12 and by mass spectrometry and determined that MED12 interacts with the TFs MEF2, CREB, and SRF. In follow-up experiments we demonstrated that MED12 interacts with the transcription factor (TF) MEF2 to regulate calcium handling genes. Current studies are focused on determining how MED12 binding coordinates gene expression through multiple TFs in cardiomyocytes. Collectively, our data demonstrate that increased MED12 expression leads to the development of heart failure, in part by dysregulation of gene expression. Therefore, precise regulation of MED12 levels is important to maintain normal cardiac function. [KB1]What about aging?

Abstract Tu044: Cardiac Mitochondrial Dysfunction Induces Region-Specific Mitochondrial Stress Response In The Brain To Adapt Neuronal Changes

Background: The hippocampus and cortex are susceptible to changes in blood supply, metabolites, and oxygenation. However, how disrupted cardiac function affects these critical areas of the brain, leading to the cognitive and neurological consequences of heart failure, remains unclear. Hypothesis: We hypothesize that disrupted cardiac function cross-talks with the brain by inducing region-specific mitochondrial stress responses, leading to adaptive changes. Methods: We utilized cardiac-specific LonP1 knockout (LonP1cKO) mice to induce heart failure within 21 days of birth. Alongside cre- control mice, we assessed cerebral blood flow using Laser speckle contrast imaging, locomotor activity through a comprehensive laboratory animal monitoring system (CLAMS), and gene expression profiles in the hippocampus and cortex by RT-PCR. Student’s ‘t’ test determined statistical significance with a p-value&lt;0.05. Results: At 21 days, LonP1cKO mice demonstrated a significant (p&lt;0.0001) reduction in cerebral blood flow (587.1±33.68, n=7) compared to the control (1034±31.26, n=5). Additionally, there were notable decreases in both X and Y-axis ambulatory and total locomotor activities in LonP1cKO mice [XAMB (100.3±6.6 vs 224±13.6 n=16), YAMB) (67.9±4.7 vs 150±8.5 n=16), XTOT (351.8±18.1 vs 534.4±26.3 n=16) and YTOT (190.7±9.6 vs 354.9±17.07 n=16). RT-PCR analysis revealed significant upregulation of genes related to hypoxia and cellular stress (Hif1a, FGf2, Atf6), mitochondrial biogenesis (mtDNA, Tfam, mt-COI, mt-COII), mitochondrial stress response proteases (LonP1, Afg3l2, Spg7, Yme1l1), and downregulation in neurotrophic factors (Bdnf, Ngf, Gfap) in the hippocampus and cortex. Conclusion: The study highlights that cardiac dysfunction in LonP1cKO mice leads to mitochondrial and cellular stress response in the brain to adapt neuronal changes, suggesting a critical link between cardiac health and brain function regulated through mitochondrial stress response pathways.

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

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. 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. 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. 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. 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.