Heart Failure Rats Research Articles

Chrysophanol Mitigates Chronic Heart Failure in Rats by Modulating ROS-Mediated Parthanatos and Pyroptosis

Chronic heart failure (CHF) triggers a cascade of events involving parthanatos and pyroptosis, culminating in cellular malfunction, inflammation, and tissue degeneration. This study aims to inquire into the inherent mechanism of chrysophanol (CHR) in the treatment of CHF.In vitro, we cultured the rat embryonic cardiomyocyte cell line H9c2. Parthanatos was initiated through N-methyl-N'-nitro-N'-nitrosoguanidine (MNNG) induction, followed by treatment with varying concentrations of CHR. The evaluation of parthanatos and pyroptosis in cardiomyocytes was assessed by western blotting. In vivo, the transverse aortic constriction (TAC) model was used to simulate CHF. The hemodynamic indices were performed to evaluate cardiac function in rats. The degree of inflammatory cell infiltration and fibrosis within cardiac tissue was assessed using hematoxylin and eosin staining and Masson's trichrome staining, respectively. Cardiac tissues were obtained and subjected to immunohistochemical analysis to assess PARP-1 expression. Subsequently, dual immunofluorescence staining (caspase-1 and NLRP3) was conducted, aiming to comprehensively evaluate the status of parthanatos and pyroptosis in the cardiac tissues of rats.In contrast to the MNNG or TAC group, the groups administered with CHR exhibited an inhibitory effect on Reactive oxygen species (ROS) expression, as well as parthanatos and pyroptosis proved by cell and animal experiments (P < 0.05). The reduced expression of PAR, PARP-1, AIF, NLRP3, IL-1β, caspase-1, and cleaved-GSDMD compared with the MNNG or TAC group proved it (P < 0.05). Moreover, compared with the TAC group, CHR significantly improved the cardiac histology of TAC rats. These findings collectively suggested the potential of CHR in ameliorating CHF.CHR may mitigate CHF in rats by modulating ROS-mediated parthanatos and pyroptosis.

CURRENT ISSUES OF MODELING HEART FAILURE AND MYOCARDIAL FIBROSIS IN RATS

HighlightsMethods for modeling heart failure in rats are classified into models requiring surgical intervention, toxic, genetic and autoimmune models, models based on the effects of physical factors, the use of special dietary regimens.It is impossible to single out a single ideal model, since the development of heart failure is a multifactorial process, it is preferable to use a combination of several methods.The correctness of the choice of the model and its compliance with the tasks of future research must be confirmed by combining several diagnostic methods for verifying myocardial fibrosis - laboratory, histological, instrumental. AnnotationDetailed study of the mechanisms of heart failure and its main pathogenetic factor, myocardial fibrosis, is required for developing new effective treatment strategies. The choice of an appropriate model is key for a reliable experimental study. The aim of the review is to systematize current data on methods for modeling heart failure in rats. The main advantages of these animals are high genetic, biochemical and physiological similarity with humans, ease of breeding, availability of maintenance, small size, while allowing for surgery. This article classifies the currently available rat models of heart failure, discusses their pathophysiological basis, timing of the formation of heart failure, clinical features, advantages and disadvantages of each experimental model. The authors have paid particular attention to methods developed by domestic scientists. Methods for assessing the developed myocardial fibrosis and the influence of drugs on its formation are considered. The study of heart failure requires reliable animal models to assess biochemical, functional, morphological changes in damaged myocardium, and controlled testing of new drugs. Should the necessity arise, specialists should use several methods simultaneously, whereas the choice of treatment strategy depends on the aim of the study.

Enhanced fibrotic potential of COL1A1hiNR4A1low fibroblasts in ischemic heart revealed by transcriptional dynamics heterogeneity analysis at both bulk and single-cell levels.

Fibroblasts in the fibrotic heart exhibit a heterogeneous biological behavior. The specific subsets of fibroblasts that contribute to progressive cardiac fibrosis remain unrevealed. Our aim is to identify the heart fibroblast (FB) subsets that most significantly promote fibrosis and the related critical genes as biomarkers for ischemic heart disease. The single nuclei RNA sequencing (snRNA-seq) and bulk RNA sequencing datasets used in this study were obtained from the Gene Expression Omnibus (GEO). The activity of gene sets related to progressive fibrosis was quantified for each FB cluster using the AddmoleculeScore function. Differentially expressed genes (DEGs) for the specific cell cluster with the highest fibrotic transcription dynamics were identified and integrated with bulk RNA sequencing data for analysis. Multiple machine learning models were employed to identify the optimal gene panel for diagnosing ischemic heart disease (IHD) based on the intersected DEGs. The effectiveness and robustness of the gene-derived diagnostic tool were validated using two independent IHD cohorts.Subsequently, we validated the signature genes using a rat post-myocardial infarction heart failure model. We conducted an analysis on high-quality snRNA-seq data obtained from 3 IHD and 4 cardiac sarcoidosis heart samples, resulting in the identification of 16 FB clusters. Cluster2 exhibited the highest gene activity in terms of fibrosis-related transcriptome dynamics. The characteristic gene expression profile of this FB subset indicated a specific upregulation of COL1A1 and several pro-fibrotic factors, including CCDC102B, GUCY1A3, TEX41, NREP, TCAP, and WISP, while showing a downregulation of NR4A1, an endogenous inhibitor of the TGF-β pathway. Consequently, we designated this subgroup as COL1A1hiNR4A1low FB. Gene set enrichment analysis (GSEA) shows that the gene expression pattern of COL1A1hiNR4A1low FB was closer to pathways associated with cardiac fibrosis. Through machine learning, ten feature genes from COL1A1hiNR4A1low FB were selected to construct a diagnostic tool for IHD. The robustness of this new tool was validated using an independent cohort and heart failure rats. COL1A1hiNR4A1low FB possess heightened capability in promoting cardiac fibrosis. Additionally, it offers molecular insights into the mechanisms underlying the regulation of the TGF-β pathway. Furthermore, the characteristic genes of COL1A1hiNR4A1 FB could serve as valuable tools for diagnosing of IHD.

High mRNA Expression of 24 Dehydrocholesterol Reductase (DHCR24) in the Treatment of Doxorubicin-Induced Heart Failure in Rats.

The objective of this study was to explore the possibility of treating heart failure in rats by delivering mRNA of 24-dehydrocholesterol reductase (DHCR24) into the body through lipid nanoparticles (LNPs). We established a heart failure rat model using doxorubicin. The experiment was divided into blank, model, mRNA stock solution cardiac injection, mRNA stock solution intravenous injection, LNP-mRNA stock solution cardiac injection, and LNP-mRNA stock solution intravenous injection groups. We directly injected DHCR24-mRNA or LNP-DHCR24-mRNA into the myocardium in three regions through an insulin needle passing through the intercostal space under the guidance of B-ultrasound. We recorded the mortality rate, body weight, 6-min walk test return times, and organ weight of rats after administration and detected the cardiac structure and function using B-ultrasound and transmission electron microscopy (TEM). Additionally, we tested for HE staining; PRDX2, Sirt3, and TRX1 protein expression; and IL-1 β, IL-10, VEGF, NT proBNP, and BNP cytokine concentrations. Compared with the model group, the administration of DHCR24-mRNA significantly reduced mortality; decreased weight loss, the ratio of heart to tibia length, and spleen weight; and improved rat motility. The administration of DHCR24-mRNA can postpone the pathological morphological alterations of myocardial cells and reduce inflammatory infiltration. In terms of biochemistry, the administration of DHCR24-mRNA can increase the expression of the PRDX2, Sirt3, and TRX1 proteins; increase the concentrations of IL-10 and VEGF; and reduce the concentrations of IL-1β, NT proBNP, and BNP. The administration of DHCR24-mRNA can also delay the process of heart failure. The delivery and therapeutic effect of DHCR24-mRNA encapsulated in LNPs were better when compared to the other groups. DHCR24-mRNA encapsulated in LNPs can be effectively administered to rats with heart failure and exhibits some curative effects.

Nerol attenuates doxorubicin-induced heart failure by inhibiting cardiomyocyte apoptosis in rats.

As a broad-spectrum anti-tumour drug, the clinical application of DOX is often limited owing to its cardiotoxicity. Nerol is a naturally occurring compound with both anti-inflammatory and antioxidant properties. However, the ability of Nerol to improve DOX-induced heart failure and its underlying mechanisms remain unclear. Rat models of DOX-induced heart failure were established and rats were treated with various doses of Nerol. Apoptosis in cardiomyocytes was detected using TUNEL staining and the expression levels of apoptosis-related proteins were detected using western blotting and immunofluorescence. In addition, mitochondrial structure was observed using electron microscopy, mitochondrial membrane potential was detected using a JC-1 fluorescent probe, and superoxide dismutase were detected to comprehensively evaluate the regulatory effect of Nerol on mitochondrial function and oxidative stress. Analysis showed that the number of apoptotic cardiomyocytes was significantly reduced after Nerol treatment, accompanied by the downregulation of Bax protein expression and upregulation of Bcl-2 protein expression, suggesting that Nerol may inhibit the apoptotic process of cardiomyocytes by regulating the balance of Bcl-2 family proteins. In addition, the mitochondrial function of Nerol-treated rats was protected, as indicated by the stability of the mitochondrial membrane potential, integrity of mitochondrial morphology. These changes suggest that Nerol may reduce the severity of heart failure by improving mitochondrial function. Nerol plays a positive role in alleviating DOX-induced heart failure in rats, possibly by inhibiting cardiomyocyte apoptosis. These findings provide novel evidence and potential targets for developing new cardioprotective drugs.

Brainstem C1 neurons mediate heart failure decompensation and mortality during acute salt loading.

Heart failure (HF) is an emerging epidemic worldwide. Despite advances in treatment, the morbidity and mortality rate of HF remain high, and the global prevalence continues to rise. Common clinical features of HF include cardiac sympathoexcitation, disordered breathing, and kidney dysfunction; kidney dysfunction strongly contributes to sodium retention and fluid overload, leading to poor outcomes of HF patients. We have previously shown that brainstem pre-sympathetic neurons (C1) from the rostral ventrolateral medulla (RVLM) play a key role in sympathetic regulation in experimental models of HF. However, the role of RVLM-C1 neurons during salt-loading in the context of HF is unknown. This study tests whether RVLM C1 neurons drive cardiorespiratory decompensation and ultimately lead to sudden death in HF rats. Adult male Sprague-Dawley rats underwent arteriovenous shunt to induce HF with preserved ejection fraction (HFpEF). Two weeks after HFpEF induction, bilateral selective ablation of RVLM C1 neurons was performed using anti-dopamine β-hydroxylase-saporin toxin. Animals were then fed a high Na+ diet (3% Na+ in food and 2% Na+ in water) for 3 weeks to induce compensated-to-decompensated HF state transition. Echocardiography, cardiac autonomic function, breathing function, and survival were assessed during the progression of HF. Salt loading resulted in marked decompensation in HF rats, as evidenced by a significant decrease in survival rates (survival: 10% vs. 100% HFpEF + Na+ vs. HFpEF). Furthermore, HFpEF + Na+ animals showed a further increase in cardiac sympathetic drive and more severe disordered breathing, including higher hypoxia-related epochs (i.e. apnoeas/hypopnoeas), compared with HF. Ablation of RVLM C1 neurons partly reduced the excessive cardiac sympathoexcitation during salt loading in HF, improved the exaggerated disordered breathing in HFpEF+ Na+ rats, and reduced decompensation-linked mortality. We found that hypoxia, but not high sodium, was the major contributor to impaired calcium handling in isolated adult cardiomyocytes. Our results strongly suggest that RVLM C1 neurons contribute to acute HF decompensation during salt loading by a mechanism encompassing further increases in sympathetic outflow and hypoxia-related breathing disorders. This mechanism may ultimately impact cardiac contractility through cardiomyocyte calcium mishandling, increasing morbidity and mortality.

SGLT2 inhibition alters substrate utilization and mitochondrial redox in healthy and failing rat hearts.

Previous studies highlight the potential for sodium-glucose cotransporter type 2 (SGLT2) inhibitors (SGLT2i) to exert cardioprotective effects in heart failure by increasing plasma ketones and shifting myocardial fuel utilization toward ketone oxidation. However, SGLT2i have multiple in vivo effects and the differential impact of SGLT2i treatment and ketone supplementation on cardiac metabolism remains unclear. Here, using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodology combined with infusions of [13C6]glucose or [13C4]βOHB, we demonstrate that acute SGLT2 inhibition with dapagliflozin shifts relative rates of myocardial mitochondrial metabolism toward ketone oxidation, decreasing pyruvate oxidation with little effect on fatty acid oxidation in awake rats. Shifts in myocardial ketone oxidation persisted when plasma glucose levels were maintained. In contrast, acute βOHB infusion similarly augmented ketone oxidation, but markedly reduced fatty acid oxidation and did not alter glucose uptake or pyruvate oxidation. After inducing heart failure, dapagliflozin increased relative rates of ketone and fatty acid oxidation, but decreased pyruvate oxidation. Dapagliflozin increased mitochondrial redox and reduced myocardial oxidative stress in heart failure, which was associated with improvements in left ventricular ejection fraction after 3 weeks of treatment. Thus, SGLT2i have pleiotropic effects on systemic and heart metabolism, which are distinct from ketone supplementation and may contribute to the long-term cardioprotective benefits of SGLT2i.

The Role of NAD+ in Myocardial Ischemia-induced Heart Failure in Sprague-dawley Rats and Beagles.

Nicotinamide adenine dinucleotide (NAD+) participates in various processes that are dysregulated in cardiovascular diseases. Supplementation with NAD+ may be cardioprotective. However, whether the protective effect exerted by NAD+ in heart failure (HF) is more effective before acute myocardial infarction (MI) or after remains unclear. The left anterior descending arteries of male Sprague Dawley rats and beagles that developed HF following MI were ligated for 1 week, following which the animals were treated for 4 weeks with low, medium, and high doses of NAD+ and LCZ696. Cardiac function, hemodynamics, and biomarkers were evaluated during the treatment period. Heart weight, myocardial fibrosis, and MI rate were measured eventually. Compared with the HF groups, groups treated with LCZ696 and different doses of NAD+ showed increased ejection fractions, fractional shortening, cardiac output, and stroke volume and decreased end-systolic volume, end-systolic dimension, creatine kinase, and lactic dehydrogenase. LV blood pressure was lower in the HF group than in the control group, but this decrease was significantly greater in the medium and high NAD+ dose groups. The ratios of heart weight indexes, fibrotic areas, and MI rates in the CZ696 and medium and high NAD+ dose groups were lower than those in the HF group. Medium and highdose NAD+ showed superior positive effects on myocardial hypertrophy, cardiac function, and myocardial fibrosis and reduced the MI rate.

Effect of an Enteral Formula Enriched With ω-3 Fatty Acids, Carnitine, and Vitamin D on Body Weight, Heart Weight, and Blood Biochemical Parameters in a Dahl Rat Heart Failure Model.

Malnutrition is known to worsen the prognosis of chronic heart failure (HF). To gain information that may be helpful in establishing appropriate nutritional interventions for chronic HF, this study was performed to investigate the efficacy of nutritional management with 2 enteral formulas, EH, with a standard nutritional composition, and ER, fortified with omega-3 fatty acids, vitamin D, and carnitine. Experiments were performed in a Dahl rat HF model. After being fed a standard rodent feed (MF) containing 8% NaCl (high salt-MF [HS-MF]) from 6 to 11 weeks of age, rats were assigned to freeze-dried EH or ER diets with an NaCl concentration of 8% (HS-ER or HS-EH) until 18 weeks of age. Serum albumin was significantly higher at 14 and 17 weeks of age in rats fed the HS-ER and HS-EH diets compared with those remaining on the HS-MF diet. Body weight was also significantly higher at 14 and 17 weeks of age in animals fed the HS-ER diet, showing that nutritional deterioration was prevented. In addition, heart weight was significantly lower at 18 weeks of age in the HS-ER group than that in the HS-MF group, suggesting that cardiac hypertrophy was prevented. This study demonstrated improved nutritional status in a HF model in Dahl rats presumably owing to differences in nutritional composition in the diets. Future studies are needed to explore optimal nutritional management with enteral formulas in patients with chronic HF.

A150: Analysis of the Mechanism of Resveratrol's Action on Myocardial Energy Metabolism in Exercise-Induced Fatigue Rats

Background/Purpose: Promotional effects of resveratrol on myocardial mitochondrial energy metabolism in exercise-induced fatigue rats were investigated by network pharmacology and animal experiments. Method: In the present study, the effects of resveratrol on myocardial energy metabolism were assessed using network pharmacology with enrichment analysis. Forty-eight healthy male SD rats of 6–8 weeks of age were selected and randomly divided into blank control group (C), resveratrol administration group (R), exercise fatigue group (E), and exercise fatigue + resveratrol administration group (ER) with 12 rats in each group. Rats in E group and the exercise fatigue + ER group were weight-bearing 5% swimming for 60 min per day, exercising 6 days a week and 1 day off for 6 weeks. Results: 1,359 exercise-induced fatigue disease targets, 2,385 heart failure disease targets, and 266 resveratrol targets were screened; a total of 62 intersecting targets were identified. The GO-enriched pathway analysis showed that resveratrol treatment of exercise-induced fatigue rat heart failure mainly affected three aspects: Biological processes (circulatory system, regulatory system, and positive regulation of cell migration), cell synthesis (septal rafts, membrane microregion, and perinuclear region), and molecular functions (heme binding, tetrapyrrole binding, and protease activity); KEGG-enriched pathway analysis showed that resveratrol treatment of exercise-induced fatigue rat heart failure was mainly affected from cancer pathway, lipid and atherosclerosis pathway, and AMPK pathway. Compared with C, E rats showed a significant increase in heart weight and body weight (P &lt; 0.05), a significant increase in the activity levels of CK-MB and cTnI (P &lt; 0.01), significantly lower activity levels of myocardial COX and SDH (P &lt; 0.01, P &lt; 0.05), and significant decreases in the activity levels of the mitochondrial energy metabolism-related genes SIRT1, PGC-1Α, and ERRΑ with significantly lower mRNA expression levels (P &lt; 0.01). Compared with E, ER rats showed a significant reduction in heart weight and body weight (P &lt; 0.05), a significant reduction in the activity levels of CK-MB and cTnI (P &lt; 0.05), a significant increase in the activity levels of myocardial COX and SDH (P &lt; 0.01), and the mRNA of SIRT1, PGC-1Α, and ERRΑ expression levels were all significantly increased (P &lt; 0.05). Conclusion/Discussion: Resveratrol ameliorated the extent of myocardial injury by improving myocardial energy metabolism in exercise-induced fatigue rats.

Mechanism of jianxin granules in the treatment of heart failure based on proteomics and metabolomics

BackgroundHeart failure (HF) is associated with high mortality and rehospitalization rates, highlighting the need for novel therapeutic approaches. Jianxin (JX) granules, a Traditional Chinese Medicine formulation, have been patented for the treatment of HF. However, the specific therapeutic effects and underlying mechanisms of JX granules have not been fully elucidated. This study aimed at investigating the effects and mechanism of JX granules in the treatment of HF based on proteomics and metabolomic profiling.MethodsHF model was established in rats by ligation of left coronary artery. The successfully modeled rats were randomly divided into three groups: the model group, the JX granules group, and Sacubitril/Valsartan (S/V) group. Four weeks after treatment, left ventricular (LV) function was evaluated via echocardiography. LV fibrosis and apoptosis were examined through histological analyses, while mitochondrial morphology was assessed using transmission electron microscopy. Quantitative assessment of oxidative stress was also conducted. Proteomics was used to identify the differentially expressed proteins and potential pathways. Metabolomics was utilized to elucidate the variations in metabolism. Then western blotting and in vitro analyses were performed.ResultsA rat model of HF was established, evidenced by a decrease in left ventricular ejection fraction (LVEF), stroke volume (SV), and left ventricular fractional shortening (LVFS), alongside diminished adenosine triphosphate (ATP) content, elevated oxidative stress, augmented apoptosis, and disrupted pyruvate metabolism. Treatment with JX granules ameliorated these effects, improving systolic function, reducing ventricular chamber size, and increasing LVEF, SV, and LVFS, as assessed by echocardiography. Additionally, JX granules attenuated cardiac fibrosis and improved mitochondrial structure, as evidenced by less vacuolation and clearer mitochondrial cristae, when compared to the model group. The treatment also regulated apoptosis-related protein expression, partially reversing the increase in cleaved Caspase-9, cleaved Caspase-3, and Bax and the suppression of Bcl-2 observed in the heart failure rats. All of these effects were similar to S/V. Proteomic and metabolomic analyses identified key differential genes, such as triosephosphate isomerase 1 (TPI1), lactate dehydrogenase B (LDHB), pyruvate kinase M (PKM), protein kinase B (Akt), Pyruvate Dehydrogenase Beta (PDHB) and lactate dehydrogenase A (LDHA), as well as vital pathways including carbon metabolism, the PI3K-Akt signaling pathway, pyruvate metabolism, and HIF-1α signaling pathway. Moreover, JX granules mitigated oxidative stress, inhibited apoptosis, and activated Akt in H9c2 cells exposed to angiotensin II, which could be reversed by the PI3K inhibitor LY294002.ConclusionJX granules improve HF in parallel to the efficacy of S/V, at least in part, through enhancing pyruvate metabolism, inhibiting oxidative stress and activating PI3K/Akt pathway.

Circulating mitochondria carrying cGAS promote endothelial Secreted group IIA phospholipase A2-mediated neuroinflammation through activating astroglial/microglial Integrin-alphavbeta3 in subfornical organ to augment central sympathetic overdrive in heart failure rats

BackgroundSympathoexcitation, a manifestation of heart–brain axis dysregulation, contributes to the progression of heart failure (HF). Our recent study revealed that circulating mitochondria (C-Mito), a newly identified mediator of multi-organ communication, promote sympathoexcitation in HF by aggravating endothelial cell (EC)-derived neuroinflammation in the subfornical organ (SFO), the cardiovascular autonomic neural center. The precise molecular mechanism by which C-Mito promotes SFO-induced endothelial neuroinflammation has not been fully elucidated. ObjectiveC-Mito carrying cGAS promote sympathoexcitation by targeting PLA2G2A in ECs of the SFO in HF rats. MethodsMale Sprague–Dawley (SD) rats received a subcutaneous injection of isoprenaline (ISO) at a dosage of 5 mg/kg/day for seven consecutive days to establish a HF model. C-Mito were isolated from HF rats and evaluated. The level of cGAS, a dsDNA sensor recently discovered to be directly localized on the outer membrane of mitochondria, was detected in C-Mito. C-Mito from HF rats (C-MitoHF) or control rats (C-MitoCtrl) were intravenously infused into HF rats. The accumulation of C-Mito in the ECs in the SFO was detected via double immunofluorescence staining. The SFO was processed for RNA sequencing (RNA-Seq) analysis. Secreted group IIA phospholipase A2 (PLA2G2A), the key gene involved in C-MitoHF-associated SFO dysfunction, was identified via bioinformatics analysis. Upregulation of PLA2G2A in the SFO ECs was assessed via immunofluorescence staining and immunoblotting, and PLA2G2A activity was evaluated. The interaction between cGAS and PLA2G2A was detected via co-immunoprecipitation. The dowstream molecular mechanisms of which PLA2G2A induced astroglial/microglial activation were also investigated. AAV9-TIE-shRNA (PLA2G2A) was introduced into the SFO to specifically knockdown endothelial PLA2G2A. Neuronal activation and glial proinflammatory polarization in the SFO were also evaluated. Renal sympathetic nerve activity (RSNA) was measured to evaluate central sympathetic output. Cardiac sympathetic hyperinnervation, myocardial remodeling, and left ventricular systolic function were assessed in C-Mito-treated HF rats. ResultsRespiratory functional incompetence and oxidative damage were observed in C-MitoHF compared with C-MitoCtrl. Surprisingly, cGAS protein levels in C-MitoHF were significantly higher than those in C-MitoCtrl, while blocking cGAS with its specific inhibitor, RU.521, mitigated respiratory dysfunction and oxidative injury in C-MitoHF. C-Mito entered the ECs of the SFO in HF rats. RNA sequencing revealed that PLA2G2A is a key molecule for the induction of SFO dysfunction by C-MitoHF. The immunoblotting and immunofluorescence results confirmed that, compared with C-MitoCtrl, C-MitoHF increased endothelial PLA2G2A expression in the SFO of HF rats, which could be alleviated by attenuating C-MitoHF-localized cGAS. Furthermore, we found that cGAS directly interacts with PLA2G2A, increased the activity of PLA2AG2, which produced arachidonic acid, and also promoted PLA2G2A secretion in brain ECs. In addition, the inhibition of PLA2G2A in brain ECs significantly mitigated the proinflammatory effect of conditioned cell culture medium from C-MitoHF-treated ECs on astroglia and microglia. Also, we found that PLA2G2A secreted from ECs insulted by C-Mito induced neuroinflammation through activating astriglial/microglial Integrin-alphavbeta3 in the SFO, which further promote central sympathetic overdrive in HF rats. Specific knockdown of endothelial PLA2G2A in the SFO mitigated C-MitoHF-induced presympathetic neuronal sensitization, cardiac sympathetic hyperinnervation, RSNA activation, myocardial remodeling, and systolic dysfunction in HF rats. ConclusionC-Mito carrying cGAS promoted cardiac sympathoexcitation by directly targeting PLA2G2A in the ECs of the SFO in HF rats. Secreted PLA2G2A derived from ECs insulted by C-Mito induced neuroinflammation through activating astriglial/microglial Integrin-alphavbeta3 in the SFO, which further promote central sympathetic overdrive in HF rats. Our study indicated that inhibiting cGAS in C-Mito might be a potential treatment for central sympathetic overdrive in HF.

Angiotensin-II drives changes in microglia–vascular interactions in rats with heart failure

Activation of microglia, the resident immune cells of the central nervous system, leading to the subsequent release of pro-inflammatory cytokines, has been linked to cardiac remodeling, autonomic disbalance, and cognitive deficits in heart failure (HF). While previous studies emphasized the role of hippocampal Angiotensin II (AngII) signaling in HF-induced microglial activation, unanswered mechanistic questions persist. Evidence suggests significant interactions between microglia and local microvasculature, potentially affecting blood–brain barrier integrity and cerebral blood flow regulation. Still, whether the microglial-vascular interface is affected in the brain during HF remains unknown. Using a well-established ischemic HF rat model, we demonstrate the increased abundance of vessel-associated microglia (VAM) in HF rat hippocampi, along with an increased expression of AngII AT1a receptors. Acute AngII administration to sham rats induced microglia recruitment to brain capillaries, along with increased expression of TNFα. Conversely, administering an AT1aR blocker to HF rats prevented the recruitment of microglia to blood vessels, normalizing their levels to those in healthy rats. These results highlight the critical importance of a rather understudied phenomenon (i.e., microglia-vascular interactions in the brain) in the context of the pathophysiology of a highly prevalent cardiovascular disease, and unveil novel potential therapeutic avenues aimed at mitigating neuroinflammation in cardiovascular diseases.

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&lt;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&lt;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&lt;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&lt;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.

The Role of Delta-Opioid Receptor in Mediating the Cardioprotective Effects of Morphine Preconditioning via the JAK2/STAT3 Pathway in a Failing Heart

BACKGROUND: Failing heart is more likely to suffer from myocardial ischemia/reperfusion (I/R) injury. This poses a great challenge for anesthesiologists in managing patients with heart failure during major surgery. Evidence from animal studies suggests that the delta-opioid receptor (DOR) contributes to alleviating acute myocardial injuries. However, little is known regarding the cardioprotective effects of cardiac DOR in patients with chronic heart failure. This study aimed to examine DOR expression in failing hearts and explore how DOR regulates the Janus kinase signal transducer and activator of the transcription-3 (JAK/STAT3) pathway to mediate morphine-induced cardio protection in heart failure. METHODS: We measured the DOR protein levels in human and rat heart tissues with chronic heart failure. To investigate the cardioprotective role of DOR, we administered the DOR-specific antagonist, naltrindole (NTD), and JAK2 inhibitor, AG490, before morphine preconditioning (MPC) in an isolated perfusion model of myocardial I/R injury in postinfarcted failing rat heart. We examined the infarct size, cardiac enzymes, cardiac function, cardiomyocyte apoptosis, apoptosis-related proteins, and STAT3 phosphorylation in the heart. RESULTS: The protein levels of DOR were significantly elevated in the myocardial tissues of humans and rats with chronic heart failure, by 1.4-fold (mean difference 0.41; 95% confidence interval [CI], 0.04–0.78; P = .032) and 2.3-fold (mean difference 1.26; 95% CI, 0.25–2.28; P = .009), respectively, compared to control tissues. Disease severity positively correlated with DOR expression (human: R2 = 0.316, P = .004; rat: R2 = 0.871, P = .021). Blocking DOR substantially reversed the cardioprotective effects of MPC in postinfarcted rat hearts, increasing the mean (standard deviation) percentage of infarct size from 15.0 (3.9)% to 30.8 (7.7)% (P &lt; .001). Similarly, AG490 inhibited MPC restoration of cardiomyocyte apoptosis (33.3 [4.2]% vs 16.6 [3.4]%; P &lt; .001). Both NTD and AG490 markedly suppressed STAT3 phosphorylation by 60.1% (mean difference 0.60; 95% CI, 0.27–0.93; P = .002) and 44.1% (mean difference 0.44; 95% CI, 0.06–0.83; P = .027), respectively, and also lowered the Bcl-2/Bax ratio by 85.5% (mean difference 0.86; 95% CI, 0.28–1.43; P = .006) and 68.2% (mean difference 0.68; 95% CI, 0.51–0.85; P &lt; .001) respectively in heart tissues at the end of reperfusion. CONCLUSIONS: DOR protein levels increased in failing hearts of both humans and rats. Blocking cardiac DOR selectively reduced morphine-induced cardio protection by inhibiting the JAK2/STAT3 pathway. These findings indicate that cardiac DOR is a potential therapeutic target for protecting against heart failure due to I/R injury.

Impaired oxytocin signalling in the central amygdala in rats with chronic heart failure.

Heart failure (HF) patients suffer from cognitive decline and mood impairments, but the molecular signals and brain circuits underlying these effects remain elusive. The hypothalamic neuropeptide oxytocin (OT) is critically involved in regulating mood, and OTergic signalling in the central amygdala (CeA) is a key mechanism that controls emotional responses including anxiety-like behaviours. Still, whether an altered OTergic signalling contributes to mood disorders in HF remains unknown. To address this, we used an ischaemic rat HF model, along with a highly multidisciplinary approach, to mechanistically study multiple levels of the hypothalamus-to-CeA OTergic circuit in male rats with HF. We aimed to test the hypothesis that sustained activation of the OT system following an infarct leads to depletion of OT content in this pathway, with subsequent changes in OT receptor expression and blunted modulation of local GABAergic circuits. We found that most of OTergic innervation of the CeA originated from the supraoptic nucleus (SON). While no differences in the numbers of SON→CeA OTergic neurons was observed between sham and HF rats, we observed a blunted content and release of OT from axonal terminals within the CeA. Moreover, we report downregulation of neuronal and astrocytic OT receptors, and impaired OTR-driven GABAergic synaptic activity within the CeA microcircuit of HF rats. We provide the first evidence that male HF rats display perturbations in the hypothalamus-to-amygdala OTergic circuit, laying the foundation for future translational studies targeting either the OT system or GABAergic amygdalar microcircuit to ameliorate mood impairments in rats or patients with chronic HF. KEY POINTS: Heart failure patients suffer from cognitive decline, depression and mood impairments, but the underlying mechanisms remain elusive. Acting within the central amygdala, the neuropeptide oxytocin regulates emotional responses, including anxiety-like behaviours. However, whether changes in oxytocin signalling occurs during heart failure is unknown. In this study, we used an ischaemic rat heart failure model to mechanistically study multiple levels of the hypothalamus-to-amygdala oxytocinergic circuit in this disease. We report an overall blunted oxytocinergic signalling pathway in rats with heart failure, including blunted content and release of oxytocin from axonal terminals, downregulation of neuronal and astrocytic oxytocin receptors, and impaired oxytocin-driven GABAergic synaptic activity within the central amygdala microcircuit of HF rats. These studies shed light on mechanisms that contribute to mood disorders in cardiovascular disease states and help to identify potential molecular targets for their improved treatment.

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.

Failing hearts are more vulnerable to dobutamine and caffeine–induced ventricular arrhythmias: ameliorated with dantrolene treatment

BackgroundCompared with normal hearts, failing hearts are more vulnerable to develop atrial fibrillation under sympathetic stimulation. It has been shown that dobutamine and caffeine challenge can induce spontaneous ventricular tachyarrhythmias in normal hearts. ObjectiveThis study was designed to investigate whether failing hearts have increased vulnerability to dobutamine and caffeine induced ventricular arrhythmias, and whether dantrolene treatment provides therapeutic benefits in this condition. MethodsA myocardial infarction (MI)-heart failure (HF) rat model was used 2 months after surgery. Sham-surgery animals served as the controls. MI-HF rats were randomized into MI-HF-untreated and MI-HF-dantrolene treated groups. Dobutamine (25μg/kg, IP) and caffeine (50mg/kg, IP) were administered acutely to induce ventricular arrhythmias. MI-HF-dantrolene group received dantrolene (10mg/kg, IP) 30 minutes before the arrhythmia test. Spontaneous Ca2+ sparks in isolated ventricular myocytes from control and MI-HF rats were also examined. ResultsDobutamine induced less inotropic response in MI-HF rats than in controls. Dobutamine + caffeine induced ventricular tachyarrhythmias in 9/10 MI-HF rats, while no ventricular arrhythmia was induced in the controls (p<0.01). Dantrolene treatment significantly decreased ventricular arrhythmia inducibility (2/10, P<0.05) in MI-HF rats. In isolated ventricular myocytes, Ca2+ sparks were significantly increased in MI-HF rats, and dantrolene treatment decreased Ca2+ sparks in these animals. ConclusionAlthough dobutamine evoked less inotropic effects, failing hearts were more vulnerable to dobutamine and caffeine induced ventricular tachyarrhythmias. Dantrolene treatment decreased Ca2+ sparks in isolated ventricular myocytes from failing hearts and ameliorated ventricular tachyarrhythmias induced by dobutamine and caffeine in MI-HF rats in vivo.

Metabolome and microbiome analyses reveal the efficacy of Shen-Fu formula in treating heart failure.

Improvement of strategies to treat heart failure (HF) has been a longstanding global goal and challenge. Shen-Fu formula (SF), as a classic herbal preparation, has demonstrated efficacy in treating HF in clinical settings. However, further understanding of the therapeutic mechanisms of SF is required. In this study, metabolomics and 16S rDNA sequencing were used to analyze the effects of SF on metabolic profiling and gut microbiota in HF rats. After 4 weeks of SF treatment, the cardiac function of HF rats showed improvement, with a significant increase in ejection fraction and fractional shortening, as well as a significant decrease in left ventricular volume and mass. Metabolomics study revealed that SF regulates the levels of substances related to energy metabolism, primarily involving lysophosphatidylcholines and polyunsaturated fatty acids. In addition, we found that SF regulates the structure of the microbial community in HF rats and modulates the balance between probiotic and pathogenic bacteria. Furthermore, the SF combination exhibited a superior effect that was better than the use of each herb separately. These results demonstrate the potential of SF therapy in the management of HF and highlight the role of SF in regulating fatty acid metabolism and gut microbiome during HF.

Huangqi-Danshen decoction improves heart failure by regulating pericardial adipose tissue derived extracellular vesicular miR-27a-3p to activate AMPKα2 mediated mitophagy

BackgroundHuangqi-Danshen decoction (HDD) is a classic traditional Chinese medicine for treating heart failure. Pericardial adipose tissue (PAT) has recently gained increasing attention in cardiovascular diseases. PurposeThis study aimed to investigate the effect of pericardial adipose tissue-derived extracellular vesicles on heart failure, the protective effect of HDD on myocardial remodel in heart failure rats, and identify the potential molecular mechanisms involved. MethodsUPLC-MS/MS identified active components of HDD. Extracellular vesicles (EVs) from pericardial adipose tissue of sham-operated and HF rats were identified through transmission electron microscopy, nanoparticle tracking analysis and western blot. EVs were co-cultured with H9c2 cardiomyocytes in order to examine their uptake and effects. MicroRNA sequencing, dual-luciferase reporter assay and PCR were conducted for exploring specific mechanisms of EVs on hypertrophic cardiomyocytes. In vivo, heart failure was modeled in rats via transverse aortic constriction (TAC). In vitro, the hypertrophic cardiomyocyte model were established using Ang II-induced H9c2 cardiomyocytes. ResultsUPLC-MS/MS identified 11 active components in serum of HDD administrated rats. Echocardiography showed HDD improved cardiac function in TAC model rats. HE and Masson staining indicated HDD ameliorated myocardial hypertrophy and fibrosis. MicroRNA sequencing found that HDD treatment resulted in 37 differentially expressed miRNAs (DMEs) (p < 0.05 and |log2FC| ≥ 1). KEGG analysis revealed that DEMs were enriched in the AMPK signaling pathway. PCR identified miR-27a-3p with the greatest difference in AMPK-related DMEs. Dual-luciferase reporter assay and Targetscan website were utilized to identify the target relationship between miR-27a-3p and PRKAA2 (AMPKα2). The miR-27a-3p negatively regulated AMPKα2 to inhibit mitophagy mediated by PINK1/Parkin pathway. HDD inhibited miR-27a-3p secretion from failing heart pericardial adipose tissue-derived extracellular vesicles, thereby improving inflammation, cardiac function, and myocardial remodeling through above pathways. ConclusionHDD inhibited the PAT-derived extracellular vesicular miR-27a-3p in failing hearts to activate AMPK/PINK1/Parkin signaling-mediated mitophagy, which improved cardiomyocyte energy metabolism, myocardial remodeling and heart failure.