Heart Tissue Research Articles

Effect of Lead, Cadmium, and Their Combination on the Heart Rate Regulation in Nonlinear Rats.

We studied heart rate variability (HRV) and the concentrations of heavy metals in the heart tissue after 14-fold peroral administration of heavy metal salts: lead acetate (50 mg/kg), cadmium chloride (5 mg/kg), and their combination. After administration of lead, its concentration in the myocardium exceeded the control values by 1.2 times or did not change in case of combination with cadmium; after administration of cadmium, its concentration in the myocardium exceeded the control value by 6.1 times or by 2 times after combined administration. After lead administration, a moderate increase in HR, low values of stress and centralization indices, and an increase in the power in all ranges of the HRV spectrum were recorded. After cadmium intoxication, a tendency to a decrease in heart rhythm variability, a moderate increase in HR, stress and centralization indices, and an increase in the contribution of VLF waves in the HRV spectrum were observed. After combined administration, a pronounced increase in HR and stress index and a moderate increase in the centralization of heart rhythm control were recorded, which was similar to changes in HRV observed after administration of cadmium alone. In the experiment, the concentration of cadmium in the myocardium increased to a much greater extent than the concentration of lead. After lead administration, the autonomous type of regulation persisted and parasympathetic influences increased. Cadmium apparently acts as a stress factor and increases the role of sympathoadrenal influences and central ergotropic structures in the heart rhythm regulation.

Examining the Cardioprotective Effects of Aerobic Exercise Combined with Crocin or Berberine on Methamphetamine-Induced Heart Damage in Female Rats

Background: While the harmful effects of methamphetamine abuse on the heart are well-known, the solutions to deal with these damages are not well-known. Objectives: This study aimed to investigate whether aerobic exercise combined with supplements such as Crocin and Berberine can potentially protect against methamphetamine-induced changes in the heart tissue of female rats. Methods: Forty-two female rats were randomly assigned into seven groups (n = 6). The groups included healthy control, methamphetamine, methamphetamine + exercise, methamphetamine + Crocin, methamphetamine + Berberine, methamphetamine + exercise + Crocin, and methamphetamine + exercise + Berberine group. Methamphetamine (10 mg/kg) was injected intraperitoneally over five days. The animals were administered Crocin via intraperitoneal injection at 40 mg/kg during a four-week withdrawal period. At the same time, Berberine was dissolved in drinking water at 100 mg/kg concentration. The aerobic training consisted of running at 25 m/min for 30 minutes. A light microscope was used to observe the structural changes. Data analysis was performed using non-parametric Kruskal-Wallis and Mann-Whitney U tests by SPSS 26, with a significance level of 5%. Results: The results of the study indicate that methamphetamine use causes hyperemia, inflammation, and histopathological damage in the heart cells and tissue (P = 0.001). The combination of exercise with Crocin significantly eliminated methamphetamine-induced heart tissue damage (P = 0.001) and improved cardio-respiratory endurance compared to control (P = 0.004) and methamphetamine (P = 0.01) groups. The combination of aerobic exercise with Berberine removed methamphetamine-induced heart cell damage (P = 0.001), and improved cardio-respiratory endurance compared to control (P = 0.024) and methamphetamine (P = 0.05) groups. In addition, all intervention groups showed a significant reduction in hyperemia and inflammation compared to the methamphetamine group (P = 0.001). Conclusions: A combination of exercise with either Crocin or Berberine supplements demonstrated potential benefits in mitigating some of the harmful structural effects of methamphetamine and improving cardio-respiratory endurance.

Preventive effect of imperatorin against doxorubicin-induced cardiotoxicity through suppression of NLRP3 inflammasome activation.

Cardiotoxicity is one of the major obstacles to anthracycline chemotherapy. Anthracycline cardiotoxicity is closely associated with inflammation. Imperatorin (IMP), a furocoumarin ingredient extracted from Angelica dahurica, might have potential activity in preventing anthracycline cardiotoxicity due to its anti-cancer, anti-inflammatory, anti-oxidant, cardioprotective properties. This study aims to reveal the effect of IMP on doxorubicin (DOX)-induced cardiotoxicity and its underlying mechanism. We established a rat model of DOX-induced cardiotoxicity by intraperitoneal injection with DOX (1.25mg/kg twice weekly for 6weeks), and found that both IMP (25mg/kg and 12.5mg/kg) and dexrazoxane 12.5mg/kg relieved DOX-induced reductions in heart weight, change in cardiac histopathology, and elevated serum levels of LDH, AST and CK-MB. Moreover, DOX upregulated mRNA levels of NLRP3, CASP1, GSDMD, ASC, IL-1β and IL-18, elevated protein expressions of NLRP3, ASC, GSDMD-FL, GSDMD-N, pro‑caspase‑1, caspase‑1 p20, pro‑IL‑1β and IL‑1β in heart tissues, as well as increased serum levels of pro-inflammatory cytokines including IL-1β and IL-18, however both of IMP and dexrazoxane suppressed these alterations. In addition, we carried out neonatal rat cardiomyocytes experiments to confirm the results of the in vivo study. Consistently, pretreatment with IMP 25µg/mL relieved DOX (1μg/mL)-induced cardiomyocytes injury, including decreased cell viability and reduced supernatant LDH. IMP inhibited DOX-induced activation of NLRP3 inflammasome in cardiomyocytes. In conclusion, IMP had a protective effect against DOX-induced cardiotoxicity via repressing the activation of NLRP3 inflammasome. These findings suggest that IMP may be a promising alternative or adjunctive drug for the prevention of anthracycline cardiotoxicity.

High-intensity interval training attenuates renal injury induced by myocardial ischemia-reperfusion in rats

Background: High-Intensity Interval Training (HIIT) has been recognized as an effective form of short-duration exercise. The purpose of this study was to assess whether HIIT could reduce renal injury induced by myocardial ischemia-reperfusion in rats. Methods: Male Sprague-Dawley rats were randomly assigned to the Sham Group (SHAM), Coronary Artery Occlusion (CAO) group, HIIT group, and Ischemic Precondition (IPC) group. Rats underwent 40 minutes of left anterior descending coronary artery occlusion under anesthesia, followed by 3 hours of reperfusion, to induce myocardial ischemia-reperfusion (MIR). Post-surgery, rats were sacrificed, and their blood, heart, and kidney tissues were examined. The HIIT group underwent 4 weeks of HIIT training before surgery. Results: HIIT intervention significantly reduced renal injury after MIR and the concentrations of Blood Urea Nitrogen (BUN) and Creatinine (CRE) in the serum. Moreover, pro-inflammatory cytokines, including Tumor Necrosis Factor-α (TNF-α), Interleukin-1β (IL-1β), and IL-6, were significantly decreased, while the anti-inflammatory cytokine IL-10 was significantly increased in the serum. Additionally, HIIT intervention suppressed the expression of FoxO1, BAX/Bcl-2 ratio, TNF-α, and Cleaved-caspase-3/caspase-3 ratio in kidney tissues, ultimately reducing renal cell apoptosis. Conclusion: This study is the first to demonstrate that HIIT has effects similar to IPC, significantly reducing renal injury after MIR. HIIT regulates the production of pro-inflammatory and anti-inflammatory cytokines, inhibits renal cell apoptosis, thereby reducing the occurrence of cardio-renal syndrome.

Distinct mechanisms drive divergent phenotypes in hypertrophic and dilated cardiomyopathy associated TPM1 variants.

Hypertrophic and dilated cardiomyopathies (HCM and DCM, respectively) are inherited disorders that may be caused by mutations to the same sarcomeric protein but have completely different clinical phenotypes. The precise mechanisms by which point mutations within the same gene bring about phenotypic diversity remain unclear. Our objective has been to develop a mechanistic explanation of diverging phenotypes in two TPM1 mutations, E62Q (HCM) and E54K (DCM). Drawing on data from the literature and experiments with stem cell-derived cardiomyocytes expressing the TPM1 mutations of interest, we constructed computational simulations that provide plausible explanations of the distinct muscle contractility caused by each variant. In E62Q, increased calcium sensitivity and hypercontractility was explained most accurately by a reduction in effective molecular stiffness of tropomyosin and alterations in its interactions with the actin thin filament that favor the 'closed' regulatory state. By contrast, the E54K mutation appeared to act via long-range allosteric interactions to increase the association rate of the C-terminal troponin I mobile domain to tropomyosin/actin. These mutation-linked molecular events produced diverging alterations in gene expression that can be observed in human engineered heart tissues. Modulators of myosin activity confirmed our proposed mechanisms by rescuing normal contractile behavior in accordance with predictions.

Potential ameliorative effect of Dapagliflozin on systemic inflammation-induced cardiovascular injury via endoplasmic reticulum stress and autophagy pathway.

Dapagliflozin (DPG) is a sodium-glucose cotransporter-2 inhibitor and is used in the treatment of diabetes. In this study, we aimed to investigate the effect of DPG on cardiotoxicity caused by systemic inflammation via endoplasmic reticulum (ER) stress and autophagy. Four groups of thirty-two Wistar Albino rats were created: Control (1ml oral physiological saline for five days and intraperitoneal saline on the 5th day), LPS (1ml oral physiological saline for five days and intraperitoneal 5mg/kg of LPS on the 5th day), LPS + DPG (10mg/kg of DPG orally for five days and 5mg/kg of LPS intraperitoneally on the 5th day), and DPG (10mg/kg of DPG orally for five days and 5mg/kg of SF intraperitoneally on the 5th day). Histopathological and immunohistochemical analyses were performed on heart and aorta tissues. ER stress and autophagy gene markers in heart tissues were evaluated by RT-qPCR. Oxidative stress in heart tissues and serum cardiac enzymes were analyzed by spectrophotometric method. The heart and aortic tissues of the LPS group showed increased expressions of Tumor Necrosis Factor-α (TNF-α) and Caspase-3 (Cas-3), along with mild hyperemia, slight inflammatory cell infiltrations, and myocardial cell damage. The heart tissues also showed genetically increased expressions of include binding immunoglobulin protein (BiP/ GRP78), protein kinase RNA-like ER Kinase (PERK), inositol-requiring enzyme 1 (IRE-1), activating transcription factors 4 (ATF-4), activating transcription factors 4 (ATF6), C/EBP homologous protein (CHOP), and BECLIN 1. Furthermore, Creatine kinase-MB (CK-MB) and Lactate dehydrogenase (LDH) levels in blood tissue significantly increased, according to biochemical analysis. With DPG therapy, all of these findings were reversed. In conclusion, DPG protects against the cardiotoxic effect of systemic inflammation with its antioxidant and anti-inflammatory properties by regulating ER stress and autophagy pathways.

Ferulic acid alleviates cardiac injury by inhibiting avermectin-induced oxidative stress, inflammation and apoptosis

Avermectin (AVM) is a broad-spectrum antibiotic from the macrolide class, extensively employed in fisheries and aquaculture. Nevertheless, its indiscriminate utilisation has resulted in a substantial accumulation of remnants in the aquatic ecosystem, potentially inflicting significant harm to the cardiovascular system of aquatic species. Ferulic acid (FA) is a naturally occurring compound in wheat grain husks. It possesses potent anti-inflammatory and antioxidant properties, which can help reduce cardiovascular damage. Additionally, its affordability makes it an excellent option for aquaculture usage as a feed additive. This article explored the potential of FA as a feed additive to protect against AVM-induced heart damage in carp. We subjected carp to AVM for 30 days and provided them with a diet of 400 mg/kg of FA. FA substantially reduced the pathogenic damage to heart tissue caused by AVM, as shown through hematoxylin-eosin staining. The biochemical analysis revealed that FA markedly enhanced the activity of antioxidant enzymes catalase (CAT), glutathione (GSH), and total antioxidant capacity (T-AOC) while reducing the malondialdehyde (MDA) content. Furthermore, qPCR analysis demonstrated a substantial increase in the mRNA levels of transforming growth factor-β1 (tgf-β1) and interleukin-10 (il-10) simultaneously, significantly reducing the expression levels of interleukin-10 (il-6), interleukin-1β (il-1β), tumor necrosis factor-α (tnf-α) and inductible nitric oxide synthase (inos). Through the mitochondrial apoptotic route, FA reduced AVM-induced cell death in carp heart cells by upregulating bcl-2 while downregulating the mRNA expression levels of bax, fas, caspase8 and caspase9. In summary, FA alleviated cardiac injury by inhibiting AVM-induced oxidative stress, inflammatory response, and apoptosis in carp heart tissue.

The activated caveolin-3/μ-opioid receptor complex drives morphine-induced rescue therapy in failing hearts.

Opioid analgesics can alleviate ischaemia/reperfusion (I/R) injury in chronic heart failure. However, the underlying mechanisms and targets remain unknown. Here, we investigate if caveolin-3 (Cav3) interacts with μ opioid receptors and if Cav3-μ receptor interactions play a role in morphine-induced cardioprotection in failing hearts. Cav3 and μ receptor proteins in human and rat heart tissue were determined by western blot, immunofluorescence and co-immunoprecipitation. Methyl-β-cyclodextrin (MβCD), a destroyer of caveolae, and AAV-Cav3 shRNA were used to reduce Cav3 expression in failing rat hearts. CTOP, a specific μ antagonist, was administrated before morphine preconditioning in perfused failing heart models of myocardial I/R injury. Levels of Cav3 and μ receptor proteins were significantly higher in human and rat myocardial tissues with heart failure than in control tissues. Cav3 and μ receptor expression levels were positively correlated with disease severity. The signal of the cardiac Cav3 protein was colocalized with μ receptor in both the human and rat heart sections. Disruption of caveolae in the failing heart by either MβCD or AAV-Cav3 shRNA significantly inhibits morphine-induced phosphorylation of ERK1/2 and cardioprotection. Administration of CTOP substantially reduced Cav3 expression and morphine-induced cardioprotective effect in heart failure. Our data suggest that up-regulation of the Cav3/μ receptor complex is critical for morphine protection of the failing heart against I/R injury by regulating the ERK1/2 pathway. The activated Cav3/μ receptor complex is an understudied therapeutic target for opioid treatment of heart failure and ischaemic insult.

Differential expression of nuclear-derived mitochondrial succinate dehydrogenase genes in metabolically active buffalo tissues.

Buffaloes are crucial to agriculture, yet mitochondrial biology in these animals is less studied compared to humans and laboratory animals. This research examines tissue-specific variations in mitochondrial succinate dehydrogenase (SDH) gene expression across buffalo kidneys, hearts, brains, and ovaries. Understanding these variations sheds light on mitochondrial energy metabolism and its impact on buffalo health and productivity, revealing insights into enzyme regulation and potential improvements in livestock management. RNA-seq data from buffalo kidney, heart, brain, and ovary tissues were reanalyzed to explore mitochondrial SDH gene expression. The expression of SDH subunits (SDHA, SDHB, SDHC, SDHD) and assembly factors (SDHAF1, SDHAF2, SDHAF3, SDHAF4) was assessed using a log2 fold-change threshold of + 1 for up-regulated and - 1 for down-regulated transcripts, with significance set at p < 0.05. Hierarchical clustering and differential expression analyses were performed to identify tissue-specific expression patterns and regulatory mechanisms, while Gene Ontology and KEGG pathway analyses were conducted to uncover functional attributes and pathway enrichments across different tissues. Reanalysis of RNA-seq data from different tissues of healthy female buffaloes revealed distinct expression patterns for SDH subunits and assembly factors. While SDHA, SDHB, and SDHC showed variable expression across tissues, SDHAF2, SDHAF3, and SDHAF4 exhibited tissue-specific profiles. Significant up-regulation of SDHA, SDHB, and several assembly factors was observed in specific tissue comparisons, with fewer down-regulated transcripts. Gene ontology and KEGG pathway analyses linked the up-regulated transcripts to mitochondrial ATP synthesis and the respiratory electron transport chain. Notably, tissue-specific variations in mitochondrial function were particularly evident in the ovary. This study identifies distinct SDH gene expression patterns in buffalo tissues, highlighting significant down-regulation of SDHA, SDHB, SDHC, and assembly factors in the ovary. These findings underscore the critical role of mitochondria in tissue-specific energy production and metabolic regulation, suggest potential metabolic adaptations, and emphasize the importance of mitochondrial complex II. The insights gained offer valuable implications for improving feed efficiency and guiding future research and therapies for energy metabolism disorders.

The alternative splicing landscape of infarcted mouse heart identifies isoform level therapeutic targets

Alternative splicing is an important process that contributes to highly diverse transcripts and protein products, which can affect the development of disease in various organisms. Cardiovascular disease (CVD) represents one of the greatest global threats to humans, particularly acute myocardial infarction (MI) and subsequent ischemic reperfusion (IR) injury, which involve complex transcriptomic changes in heart tissues associated with metabolic reshaping and immunological response. In this study, we used a newly developed ONT full-length transcriptomic approach and performed transcript-resolved differential expression profiling in murine models of MI and IR. We built an analytical pipeline to reliably identify and quantify alternative splicing products (isoforms), expanding on the currently available catalog of isoforms described in mice. The updated alternative splicing landscape included transcripts, genes, and pathways that were differentially regulated during IR and MI. Our study establishes a pipeline to profile highly diverse isoforms using state-of-the-art long-read sequencing, builds a landscape of alternative splicing in the mouse heart during MI and IR.

Preventive impact of probiotic supplements on heart injury and inflammatory indices in a rat model of myocardial infarction: histopathological and gene expression evaluation.

Although there is a bulk of evidence on the favorable effect of probiotics on the cardiac system, their role in the management of myocardial infarction is not clear. Three viable probiotic bacterial strains, namely Lactobacillus reuteri, Bifidobacterium longum, and Bifidobacterium lactis, were gavaged to the rats daily for 28 days prior to the induction of myocardial injury. Myocardial injury was induced by the use of isoproterenol (ISO) in the probiotics, control and sham groups. The heart tissues were catheterized to evaluate the histopathological parameters and measure the expression of genes related to inflammation. Treatment with ISO caused subendocardial necrosis and rupture of cardiac myofibrils. Pretreatment with probiotics reduced the size of myocardial infarction caused by ISO. Also, in the probiotic group, a relative decrease in the amount of tissue fibrosis and rupture of cardiomyocytes fibers was seen. Pretreatment with probiotics partially ameliorated myocardial necrosis, edema and leukocyte infiltration. Also, a remarkable decrease was detected in the expression of tissue proinflammatory genes in the pretreated group with probiotics. Thus, viable probiotic supplementation may ameliorate or prevent cardiac injury. Additional preclinical and clinical studies are required to clarify the impact of probiotics in the prevention and management of cardiovascular disease.

Methionine-SAM metabolism-dependent ubiquinone synthesis is crucial for ROS accumulation in ferroptosis induction

Ferroptosis is a cell death modality in which iron-dependent lipid peroxides accumulate on cell membranes. Cysteine, a limiting substrate for the glutathione system that neutralizes lipid peroxidation and prevents ferroptosis, can be converted by cystine reduction or synthesized from methionine. However, accumulating evidence shows methionine-based cysteine synthesis fails to effectively rescue intracellular cysteine levels upon cystine deprivation and is unable to inhibit ferroptosis. Here, we report that methionine-based cysteine synthesis is tissue-specific. Unexpectedly, we find that rather than inhibiting ferroptosis, methionine in fact plays an essential role during cystine deprivation-induced ferroptosis. Methionine-derived S-adenosylmethionine (SAM) contributes to methylation-dependent ubiquinone synthesis, which leads to lipid peroxides accumulation and subsequent ferroptosis. Moreover, SAM supplementation synergizes with Imidazole Ketone Erastin in a tumor growth suppression mouse model. Inhibiting the enzyme that converts methionine to SAM protects heart tissue from Doxorubicin-induced and ferroptosis-driven cardiomyopathy. This study broadens our understanding about the intersection of amino acid metabolism and ferroptosis regulation, providing insight into the underlying mechanisms and suggesting the methionine-SAM axis is a promising therapeutic strategy to treat ferroptosis-related diseases.

Potential cardiac-derived exosomal miRNAs involved in cardiac healing and remodeling after myocardial ischemia–reperfusion injury

Migratory cells exist in the heart, such as immune cells, fibroblasts, endothelial cells, etc. During myocardium injury, such as ischemia–reperfusion (MIRI), cells migrate to the site of injury to perform repair functions. However, excessive aggregation of these cells may exacerbate damage to the structure and function of the heart, such as acute myocarditis and myocardial fibrosis. Myocardial injury releases exosomes, which are a type of vesicle with signal transduction function and the miRNA carried by exosomes can control cell migration function. Therefore, regulating this migratory cell population through cardiac-derived exosomal miRNA is crucial for protecting and maintaining cardiac function. Through whole transcriptome RNA sequencing, exosomal miRNA sequencing and single-cell dataset analysis, we (1) determined the potential molecular regulatory role of the lncRNA‒miRNA‒mRNA axis in MIRI, (2) screened four important exosomal miRNAs that could be released by cardiac tissue, and (3) screened seven genes related to cell locomotion that are regulated by four miRNAs, among which Tradd and Ephb6 may be specific for promoting migration of different cells of myocardial tissue in myocardial infarct. We generated a core miRNA‒mRNA network based on the functions of the target genes, which may be not only a target for cardiac repair but also a potential diagnostic marker for interactions between the heart and other tissues or organs. In conclusion, we elucidated the potential mechanism of MIRI in cardiac remodeling from the perspective of cell migration, and inhibition of cellular overmigration based on this network may provide new therapeutic targets for MIRI and to prevent MIRI from developing into other diseases.

Cardiomyocyte-specific knockout of ADAM17 alleviates doxorubicin-induced cardiomyopathy via inhibiting TNFα–TRAF3–TAK1–MAPK axis

The pathogenesis of doxorubicin-induced cardiomyopathy remains unclear. This study was carried out to test our hypothesis that ADAM17 aggravates cardiomyocyte apoptosis induced by doxorubicin and inhibition of ADAM17 may ameliorate doxorubicin-induced cardiomyopathy. C57BL/6J mice were intraperitoneally injected with a cumulative dose of doxorubicin to induce cardiomyopathy. Cardiomyocyte-specific ADAM17-knockout (A17α-MHCKO) and ADAM17-overexpressing (AAV9-oeA17) mice were generated. In addition, RNA sequencing of the heart tissues in different mouse groups and in vitro experiments in neonatal rat cardiomyocytes (NRCMs) receiving different treatment were performed. Mouse tumor models were constructed in A17fl/fl and A17α-MHCKO mice. In addition, cardiomyocyte-specific TRAF3-knockdown and TRAF3-overexpressing mice were generated. ADAM17 expression and activity were markedly upregulated in doxorubicin-treated mouse hearts and NRCMs. A17α-MHCKO mice showed less cardiomyocyte apoptosis induced by doxorubicin than A17fl/fl mice, and cardiomyocyte ADAM17 deficiency did not affect the anti-tumor effect of doxorubicin. In contrast, AAV9-oeA17 mice exhibited markedly aggravated cardiomyocyte apoptosis relative to AAV9-oeNC mice after doxorubicin treatment. Mechanistically, doxorubicin enhanced the expression of transcription factor C/EBPβ, leading to increased expression and activity of ADAM17 in cardiomyocyte, which enhanced TNF-α shedding and upregulated the expression of TRAF3. Increased TRAF3 promoted TAK1 autophosphorylation, resulting in activated MAPKs pathway and cardiomyocyte apoptosis. ADAM17 acted as a positive regulator of cardiomyocyte apoptosis and cardiac remodeling and dysfunction induced by doxorubicin by upregulating TRAF3/TAK1/MAPKs signaling. Thus, targeting ADAM17/TRAF3/TAK1/MAPKs signaling holds a promising potential for treating doxorubicin-induced cardiotoxicity.

Metformin-mediated protection against doxorubicin-induced cardiotoxicity

BackgroundA phase II clinical trial of metformin (MET) for the treatment of doxorubicin (DOX)-induced cardiotoxicity (NCT02472353) failed. ObjectivesThe aims of this study were to confirm MET-mediated protection against DOX-induced cardiotoxicity and its mechanism using H9C2 cells, and to establish a Wistar rat model of DOX-induced cardiotoxicity. Subsequently, Wistar rats were utilized to identify clinically relevant indicators for evaluating MET-mediated protection against DOX-induced cardiotoxicity, thereby facilitating early transition towards successful clinical trials. MethodsMET-mediated protection was assessed using cell viability and cytotoxicity experiments. Additionally, intramitochondrial reactive oxygen species (ROS) levels were measured using an ROS fluorescent probe (dihydroethidium) to confirm the oxidative stress mechanism. Eighteen Wistar rats were randomly allocated to the control, DOX, and DOX+MET groups; and the body weight, adverse drug reactions (ADRs), myocardial injury, cardiac function, oxidative stress, and histopathology of heart tissues were compared between groups. ResultsH9C2 cells treated with MET/Dexrazoxane demonstrated dose-dependent protection against DOX-induced cardiotoxicity. The fluorescence intensity of H9C2 cells suggested DOX-induced cardiomyocyte toxicity and MET-mediated protection against DOX-induced cardiotoxicity. In vivo experiments confirmed that a rat model of DOX-induced cardiotoxicity was successfully established, but MET-mediated protection against DOX-induced cardiotoxicity was not demonstrated. This was attributed to insufficient energy intake because of ADRs, such as vomiting. ConclusionsWe confirmed the MET-mediated protection against DOX-induced cardiomyocyte toxicity and its mechanism involving the inhibition of oxidative stress in vitro experiments. It is imperative to investigate the optimal conditions for MET-mediated protection against DOX-induced cardiotoxicity in vivo or clinical trials.

Melatonin Mediates Cardiac Tissue Damage under Septic Conditions Induced by Lipopolysaccharide.

Lipopolysaccharide (LPS) is known to induce oxidative stress and inflammation, leading to significant damage in cardiac tissues. This study investigates the protective effects of melatonin (MLT) against LPS-induced oxidative damage, inflammation, and apoptosis in rat heart tissue. Rats were divided into four groups (n = 6 per group): control, melatonin-treated, LPS-treated, and LPS + melatonin-treated. Oxidative stress markers, including thiobarbituric acid-reactive substances (TBARSs) and advanced oxidation protein products (AOPPs), were measured. Additionally, inflammatory markers, such as interleukin-6 (IL-6) levels, inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content, and apoptotic markers, caspase-3, caspase-9, and acidic DNase activity, were evaluated. LPS treatment significantly increased TBARS, AOPP, and IL-6 levels, as well as the activity of caspase-3, acidic DNase and iNOS and NO content compared to the control group. Co-treatment with melatonin significantly reduced the levels of TBARS and AOPP levels, and caspase-3 and acidic DNase activities nearly matched those of the control group, while caspse-9 was still slightly increased. Interestingly, IL-6, iNOS and NO levels were significantly decreased but did not fully match the values in the control group. Melatonin mitigates LPS-induced oxidative stress, inflammation, and apoptosis in rat heart tissue by affecting all studied parameters, demonstrating its potential as a therapeutic agent for conditions characterized by oxidative stress and inflammation. Further research is warranted to explore the clinical applications of melatonin in cardiovascular diseases.

Study of the dynamics of relative expression of the EGR1 gene in rainbow trout in different tissues

The purpose of this study was to study the dynamics of the comparative level of expression of the EGR1 gene in the tissues of rainbow trout at different ages. The EGR1 gene encodes a transcription factor that influences the transcription of a large number of genes from both the 5-bar and 3-bar ends of genes. A random sample of fish aged 6, 12 and 18 months was taken for the study. To assess the expression level of the EGR1 gene, located on 14 chromosomes, a housekeeping gene was taken: G6PD. A comparative analysis of the expression level of the EGR1 gene in rectal tissues revealed a significant change in different age periods of rainbow trout. Expression in the tissues of the rectum at the age of 6 months was maximal, and at the age of 12 months it was minimal, but no significant differences were found (p = 0.2648). As a result of the analysis of changes in the level of relative expression of the EGR1 gene in the heart tissues of rainbow trout at different ages, it was found that in the group of fish aged 6 months, the expression level was maximum at the stage of 12 and 18 months (р &lt; 0.01). As a result of the study, a correlation between the size and weight parameters of rainbow trout and the level of gene expression in different eras and in different countries was established. Expression dynamics at different ages in rainbow trout were also determined.

Unveiling the Potential of Silymarin, Spirulina platensis, and Chlorella vulgaris towards Cardiotoxicity via Modulating Antioxidant Activity, Inflammation, and Apoptosis in Rats

This study assessed the possible pharmacological effects of Chlorella vulgaris (Cg), Spirulina platensis (St), and silymarin (Sl) against thioacetamide (TA)-induced cardiotoxicity in rats, with a focus on their antioxidant, cardioprotective, and anti-inflammatory properties. The following is the random grouping of sixty male rats into six groups of ten animals each: the control (negative control), TA-intoxicated group (positive control; 300 mg/kg body weight (BW)), Sl + TA group (100 mg Sl/kg BW + TA), St + TA group (400 mg St/kg BW + TA), Cg + TA (400 mg Cg/kg BW + TA), and St + Cg + TA group (400 St + 400 Cg mg/kg BW + TA) were all administered for 30 days. At the start of the study, groups 2 through 6 were administered TA intraperitoneally at a dosage of 300 mg/kg BW for two consecutive days, with a 24 h gap between each dose, to induce cardiac damage. Blood samples were obtained to measure hematological parameters and perform biochemical assays, including lipid profiles and cardiac enzymes. For histopathology and immunohistochemistry determination, tissue samples were acquired. The current findings showed that TA injection caused hematological alterations and cardiac injury, as evidenced by greater serum levels of troponin I, creatine kinase-MB, and total creatine kinase (p &lt; 0.05), as well as significantly elevated serum malondialdehyde and decreased serum total antioxidant capacity (p &lt; 0.05) concentrations. Moreover, an increase in blood low-density lipoprotein and total cholesterol concentration (p &lt; 0.05) was recorded in the TA group. There were alterations in the heart tissue’s histological structure of the TA group compared to the control ones. These alterations were characterized by vacuolar degeneration of myocytes, loss of cross striation, coagulative necrosis, and fibrosis of interstitial tissue, which was ameliorated by the supplementation of SI, St, and Cg. The TA-intoxicated group showed weak expression of B-cell lymphoma protein 2 (p &lt; 0.05) and strong immunoreactivity of tumor necrosis factor-α and B-cell lymphoma protein 2-associated X (p &lt; 0.05). However, the groups receiving Sl, St, and Cg experienced the opposite. The administration of Sl, St, Cg, and St + Cg along with TA significantly improved and restored (p &lt; 0.05) erythrogram indices, including RBCs, hemoglobin, total leukocytic count, lymphocytes, and monocyte, to the normal control values. The administration of Sl, St, and Cg alleviated the cardiotoxicity caused by TA via reducing oxidative stress, inflammatory markers, and apoptosis in heart tissue. In summary, the current findings suggest that the treatment with Sl, St, and Cg was beneficial in ameliorating and reducing the cardiotoxicity induced by TA in rats.

Unleashing the cardioprotective potential of Ezetimibe against Doxorubicin-induced cardiotoxicity in Wistar rats: Targeting oxidative stress and NF-κB-mediated inflammation

Background Doxorubicin (DOX) is a potent antineoplastic agent used in treating various adult and pediatric cancers, but it tends to provoke dose-dependent cardiotoxicity. Ezetimibe (EZE), a cholesterol-lowering drug, has been reported to possess defensive actions against oxidative stress and inflammation, which are two of the main proposed mechanisms underlying the development of DOX-induced cardiotoxicity (DIC), hence, we aimed to inspect the possible protective effect of EZE against DIC in rats. Methods 24 adult male Wistar rats were allocated into four groups of six: control, DOX, 10 mg/kg EZE plus DOX and 20 mg/kg EZE plus DOX. At the end of the study, the experimental rats were anesthetized and blood samples were collected for biochemical analysis, after which the hearts were excised and heart tissue samples were obtained for biochemical and gene expression analyses. Results Pretreatment with EZE at a dose of 10 or 20 mg/kg alleviated cardiac damage induced by DOX, as EZE blunted the rise in serum levels of cardiac injury biomarkers, including cardiac troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Additionally, pretreating rats with EZE at either dose mitigated DOX-induced oxidative stress by elevating the levels of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), with consequent reduction in the lipid peroxidation biomarker malondialdehyde (MDA) in cardiac tissues. Furthermore, pretreatment with either dose of EZE hindered DOX-mediated inflammation, where EZE suppressed cardiac nuclear factor-kappa B (NF-κB) signaling and negatively regulated the gene expression of its downstream proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) with either dose and interleukin-1 beta (IL-1β) with the higher one. Conclusions Our findings indicate that EZE exhibited cardioprotection against DIC in rats, which makes EZE an interesting area for further investigations, animal- and human-wise, that can pave the way for a potential clinical application in preventing DIC in the future.

Chronic Activation of Tubulin Tyrosination Improves Heart Function.

Hypertrophic cardiomyopathy (HCM) is the most common cardiac genetic disorder caused by sarcomeric gene variants and associated with left ventricular hypertrophy and diastolic dysfunction. The role of the microtubule network has recently gained interest with the findings that microtubule detyrosination (dTyr-MT) is markedly elevated in heart failure. Acute reduction of dTyr-MT by inhibition of the detyrosinase (VASH [vasohibin]/SVBP [small VASH-binding protein] complex) or activation of the tyrosinase (TTL [tubulin tyrosine ligase]) markedly improved contractility and reduced stiffness in human failing cardiomyocytes and thus posed a new perspective for HCM treatment. In this study, we tested the impact of chronic tubulin tyrosination in an HCM mouse model (Mybpc3 knock-in), in human HCM cardiomyocytes, and in SVBP-deficient human engineered heart tissues (EHTs). Adeno-associated virus serotype 9-mediated TTL transfer was applied in neonatal wild-type rodents, in 3-week-old knock-in mice, and in HCM human induced pluripotent stem cell-derived cardiomyocytes. We show (1) TTL for 6 weeks dose dependently reduced dTyr-MT and improved contractility without affecting cytosolic calcium transients in wild-type cardiomyocytes; (2) TTL for 12 weeks reduced the abundance of dTyr-MT in the myocardium, improved diastolic filling, compliance, cardiac output, and stroke volume in knock-in mice; (3) TTL for 10 days normalized cell area in HCM human induced pluripotent stem cell-derived cardiomyocytes; (4) TTL overexpression activated transcription of tubulins and other cytoskeleton components but did not significantly impact the proteome in knock-in mice; (5) SVBP-deficient EHTs exhibited reduced dTyr-MT levels, higher force, and faster relaxation than TTL-deficient and wild-type EHTs. RNA sequencing and mass spectrometry analysis revealed distinct enrichment of cardiomyocyte components and pathways in SVBP-deficient versus TTL-deficient EHTs. This study provides the first proof of concept that chronic activation of tubulin tyrosination in HCM mice and in human EHTs improves heart function and holds promise for targeting the nonsarcomeric cytoskeleton in heart disease.