Cardiomyocyte Metabolism Research Articles

The Ethanol Extract of Sugemule-3 Decoction Treats Isoproterenol-induced Heart Failure in Rats via PPARγ/PGC-1 Pathway

Background The herbs Baidoukou (the fruit of Amomum compactum Sol. ex Maton), Baijusheng (the fruit of Lactuca sativa L.), and Biba ( Piper longum L.) make up the traditional Mongolian medicine known as Sugemule-3 decoction. Purpose: Heart failure (HF) is severely impacted; however, the pharmacological mechanism behind it is yet unclear. This investigation looked at the Sugemule-3 ethanol extract’s therapeutic mechanism for isoproterenol-induced HF in rats. Methods To create a HF model, isoproterenol was administered to Wistar rats. Following the model’s successful establishment, various medications were administered for 4 weeks. The electrical signals of cardiac fluctuations, cardiac morphology, and function were observed using electrocardiogram (ECG) and echocardiography. The rats were killed 4 weeks later, and the hearts were observed using an electron microscope and HE staining. Cardiomyocyte apoptosis was observed using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. The levels of markers in serum were determined using enzyme-linked immunosorbent assay (ELISA). Western blot and immunohistochemistry were used to detect the expression of proteins in rats. Results Our findings show that isoproterenol injection subcutaneously interfered with the structure and function of the left ventricle, particularly during systole. In the model group, the level of oxidative stress index malondialdehyde ( p < 0.01) increased with the decrease in anti-oxidant enzymes such as superoxide dismutase ( p < 0.01) and glutathione peroxidase ( p < 0.01). Sugemule-3 ethanol extract considerably reduced the harmful effects of isoproterenol on the rat myocardium. Additionally, isoproterenol increased the level of peroxisome proliferator-activated receptor (PPAR), carnitine palmitoyl transferase-1 (CPT-1), phosphoenolpyruvate carboxylase (PEPCK), stearyl CoA desaturase-1 (SCD-1), and ubiquitin-conjugating (UCB) expression while decreasing the level of peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) expression, leading to cardiometabolic diseases. Sugemule-3 ethanol extract improved cardiac metabolism. Conclusion The findings demonstrate that Sugemule-3 ethanol extract may improve energy metabolism of cardiomyocytes and alleviate isoproterenol-induced HF through inhibiting the peroxisome proliferator-activated receptor gamma (PPARγ)/PGC-1 signaling pathway.

A retrospective study on the relationship between plasma β-hydroxybutyric acid levels and short-term prognosis of cardiac function in patients with acute myocardial infarction combined with heart failure

Abstract Background Ketone body metabolism can improve cardiomyocytes metabolism and reduce myocardial oxygen consumption; however, its role in the short-term prognosis of patients with acute myocardial infarction combined with heart failure has not been clearly elucidated. The aim of this study was to investigate the effect of β-hydroxybutyric acid, the main component of ketone bodies, on the short-term prognosis of patients with acute myocardial infarction combined with heart failure. Methods This was a retrospective observational study that enrolled patients admitted to the Qilu Hospital of Shandong University for acute myocardial infarction combined with heart failure between January 1, 2019, and December 31, 2022. According to whether β-hydroxybutyric acid was elevated or not, subjects were divided into a β-hydroxybutyric acid elevated and nonelevated groups, to observe the difference in cardiac function improvement between the two groups. Results This study included a total of 260 patients, of which 170 exhibited elevated levels of β-hydroxybutyric acid. Compared to the patients in the nonelevated group, patients in the elevated β-hydroxybutyric acid group had higher plasma levels of creatine kinase myocardial band and greater Gensini scores. Multivariate logistic regression analysis indicated that an increase in β-hydroxybutyric acid levels (odds ratio: 2.517; 95% confidence intervals: 1.394–4.597; P = 0.002) is an independent protective factor affecting the prognosis of cardiac function in patients with acute myocardial infarction combined with heart failure. Conclusion In patients with acute myocardial infarction combined with heart failure, plasma β-hydroxybutyric acid serves as an independent protective factor for short-term improvement in cardiac function.

Effect of L-Arginine on Lipid Metabolism and Morphology of Cardiomyocytes of Animals with Experimental Atherosclerosis in High-Altitude Conditions

Background: The Kyrgyz Republic, with its high-altitude regions, poses unique health challenges due to extreme geoclimatic factors. Cardiovascular disease (CVD) is prevalent in the region, and dyslipidemia, a significant risk factor for atherosclerosis and CVD, is associated with elevated serum cholesterol levels. This study investigates the effects of high-altitude environments on human health and the potential therapeutic benefits of L-arginine in regulating carbohydrate and lipid metabolism. Materials and Methods: Thirty rabbits were divided into five groups: Control (low-altitude), high-altitude (3 days), atherosclerosis model, atherosclerosis with preventive L-arginine and cholesterol treatment, and atherosclerosis with L-arginine treatment. Atherosclerosis was induced by oral cholesterol administration (500 mg/kg/day) for 60 days. L-arginine (170 mg/kg/day) was administered for 30 days for treatment and prevention. Lipid metabolism indicators (high-density lipoprotein, low-density lipoproteins, triglycerides, and total cholesterol [TC]) were measured using a biochemical autoanalyzer. Histological examination of excised plaques and myocardial morphology was performed. Results: Results showed a significant reduction in TC levels in the high-altitude group compared to the control. The atherosclerosis model group exhibited a tenfold increase in TC, which remained unchanged with preventive L-arginine and cholesterol treatment. However, L-arginine treatment alone decreased TC levels by approximately 65%, although still twice as high as the control. Conclusion: The findings suggest that L-arginine may have potential therapeutic benefits in regulating lipid metabolism and improving cardiomyocyte morphology in rabbits with induced atherosclerosis under high-altitude conditions.

Leukocyte as an adequate model for studying changes in energy metabolism in heart cells under the influence of cardiocytoprotectors in myocardial ischemia

The aim of this study was to determine the possibility of studying the nature of the influence of cardiocytoprotectors on energy metabolism in cardiomyocytes using a model of human peripheral blood leukocytes.Materials and methods. Sixty Wistar rats were divided into groups: 1) intact rats; 2) rats with experimental myocardial ischemia; 3) rats with myocardial ischemia, which were injected with cardiocytoprotector – trimetazidine, 4) meldonium, 5) cytoflavin and 6) ethoxydol. Animals were taken out of the experiment 10 days after the administration of drugs by decapitation. The activities of pyruvate dehydrogenase and citrate synthase were determined in mitochondria of myocardial homogenates and in mitochondria of leukocytes by spectrophotometric methods.Results. The decrease in pyruvate dehydrogenase and citrate synthase activity in cardiomyocytes and in leukocytes were revealed in case of myocardial ischemia modeling. The introduction of cardiocytoprotectors led to the activation of these enzymes both in heart cells and in blood leukocytes. Direct positive correlations were obtained between the activity of pyruvate dehydrogenase in the mitochondria of cardiomyocytes and in the mitochondria of leukocytes (r = 0.811; p < 0.0001); between citrate synthase activity in the mitochondria of cardiomyocytes and in the mitochondria of leukocytes (r = 0.909; p < 0.0001).Conclusion. Changes in energy metabolism in blood leukocytes under the influence of cytoprotectors reflect similar changes occurring in heart cells.

Abstract 4134837: Checkpoint Kinase 1 Attenuates Myocardial Ischemia-Reperfusion Injury Through Maintaining SIRT1-Dependent Mitochondrial Homeostasis

Background: Mitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation and cardiac repair post myocardial infarction, however, its role on mitochondrial function in I/R injury remains unknown. Research Questions: The purpose of this study is to explore the potential effects and mechanisms of CHK1 on mitochondrial homeostasis during myocardial I/R injury. Methods: To investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/knock-in mouse models were generated. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism of CHK1. The interaction between CHK1 and SIRT1 was explored using truncated plasmids. Results: CHK1 was downregulated in myocardium post I/R and neonatal mouse cardiomyocytes (NMCMs) post oxygen-glucose deprivation/re-oxygenation (OGD/R). In vivo , CHK1 overexpression protected against myocardial I/R injury, while heterogenous CHK1 knockout exacerbated cardiomyopathy. In vitro , CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266-390 domain of CHK1 interacted with the 160-583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown partially attenuated the protective role of CHK1 in I/R injury. Conclusions: Our findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.

Anthrax lethal toxin exerts potent metabolic inhibition of the cardiovascular system.

Bacillus anthracis causes anthrax through a combination of bacterial infection and toxemia. As a major virulence factor of B. anthracis, anthrax lethal toxin (LT) is a zinc-dependent metalloproteinase, exerting its cytotoxicity through proteolytic cleavage of the mitogen-activated protein kinase kinases, thereby shutting down the MAPK pathways. Anthrax lethal toxin induces host lethality mostly by targeting the cardiovascular system. Although the enzymatic activity and the molecular targets of LT have long been known, the detailed mechanisms underlying cellular/tissue/organ toxicity are still poorly understood. In this work, we sought to investigate the mechanism of LT-induced cellular damage in the cardiovascular system. We demonstrate for the first time that anthrax lethal toxin has potent inhibitory effects on the central metabolism of cardiomyocytes and endothelial cells. This is likely due to the observed downregulating of c-Myc expression through the toxin-induced inhibition of the ERK pathway. Since c-Myc is a master transcription factor controlling the expression of many rate-limiting metabolic enzymes in glycolysis and the tricarboxylic acid cycle, LT's downregulation of c-Myc may lead to the observed bioenergetic collapse, particularly, in cardiomyocytes. Since cardiac cell contraction requires continuous production of large amounts of ATP, potent inhibition of the bioenergetics of cardiomyocytes would be incompatible with life. Thus, LT-induced lethality through targeting cardiomyocytes and endothelial cells appears to be a consequence of a bioenergetic collapse, likely due to the toxin's potent inhibitory activity on the MEK-ERK-c-Myc-metabolic/bioenergetic axis within these target cells of cardiovascular system.IMPORTANCEAnthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis, the causative pathogen of anthrax disease. Anthrax lethal toxin is a metalloproteinase that cleaves and inactivates MEKs, thereby shutting down MAPK pathways, leading to host mortality primarily through targeting of the cardiovascular system. However, the detailed mechanisms underlying the toxin's cellular and tissue toxicity are still poorly understood. Here, we found that anthrax lethal toxin has potent inhibitory activity on glycolysis and oxidative phosphorylation of cardiomyocytes and endothelial cells. These effects appear to be the consequence of downregulation of c-Myc, a master transcription factor that controls many rate-limiting enzymes of glycolysis and the tricarboxylic acid cycle. With the high demand on energy for cardiac contraction, the potent inhibition of cardiomyocyte metabolism by LT would be incompatible with life. This work provides critical insights into why the cardiovascular system is the major in vivo target of LT-induced lethality.

Phosphocreatine in the treatment of chronic heart failure: Case report

Currently, there is a steady increase in the prevalence of chronic heart failure (CHF), as well as a high mortality rate associated with this condition, despite the implementation of rational pharmacotherapy. The use of quadrotherapy in clinical practice for the treatment of CHF contributes to the blocking of neurohumoral regulation by inhibiting the renin-angiotensin-aldosterone and sympathoadrenal systems, which leads to decrease in preand afterload and, respectively, to delayed and partial reverse remodeling of the heart chambers. However, these drugs don’t affect the energy metabolism of cardiomyocytes, which is still impaired in patients at the preclinical stage of CHF. In this regard, an important task of practical healthcare is the search for new schemes of a pathogenetic therapy of CHF. One of the promising directions is an adjuvant therapy, which is represented by phosphocreatine, a drug with a cardioprotective effect, proven in a large number of studies, which ensures the maintenance of myocardial energy metabolism. The use of phosphocreatin prevents further deterioration of the contractile function of the heart in patients with CHF, reduces the degree of damage to the cell membrane, improves microcirculation, and also has antiarrhythmic activity, which is especially significant in patients with a history of myocardial infarction. The drug not only improves the quality of life of patients by reducing the severity of symptoms, but also has been proven to increase myocardial contractility and reduce mortality. The purpose of the clinical case report is the description of adjuvant therapy results in a patient with CHF after using all pharmacotherapy reserves. The clinical case demonstrates the effectiveness of CHF treatment with phosphocreatine, confirmed by data from clinical, laboratory and instrumental examinations.

Phosphocreatine in the treatment of chronic heart failure: Case report

Currently, there is a steady increase in the prevalence of chronic heart failure (CHF), as well as a high mortality rate associated with this condition, despite the implementation of rational pharmacotherapy. The use of quadrotherapy in clinical practice for the treatment of CHF contributes to the blocking of neurohumoral regulation by inhibiting the renin-angiotensin-aldosterone and sympathoadrenal systems, which leads to decrease in preand afterload and, respectively, to delayed and partial reverse remodeling of the heart chambers. However, these drugs don’t affect the energy metabolism of cardiomyocytes, which is still impaired in patients at the preclinical stage of CHF. In this regard, an important task of practical healthcare is the search for new schemes of a pathogenetic therapy of CHF. One of the promising directions is an adjuvant therapy, which is represented by phosphocreatine, a drug with a cardioprotective effect, proven in a large number of studies, which ensures the maintenance of myocardial energy metabolism. The use of phosphocreatin prevents further deterioration of the contractile function of the heart in patients with CHF, reduces the degree of damage to the cell membrane, improves microcirculation, and also has antiarrhythmic activity, which is especially significant in patients with a history of myocardial infarction. The drug not only improves the quality of life of patients by reducing the severity of symptoms, but also has been proven to increase myocardial contractility and reduce mortality. The purpose of the clinical case report is the description of adjuvant therapy results in a patient with CHF after using all pharmacotherapy reserves. The clinical case demonstrates the effectiveness of CHF treatment with phosphocreatine, confirmed by data from clinical, laboratory and instrumental examinations.

Lipin1 prevents ischemic heart disease by regulating lipid homeostasis

Abstract Background Lipid metabolism plays a crucial role in the pathophysiology of cardiovascular diseases. Lipin1 plays a pivotal role in lipid metabolism regulation. In the nucleus, Lipin1 acts as a transcriptional co-stimulatory molecule, interacting with peroxisome proliferator–activated receptor–gamma coactivator 1 alpha (PGC1α) and peroxisome proliferator–activated receptor alpha (PPARα). In the cytoplasm, Lipin1 functions as a phosphatidate phosphatase, converting phosphatidic acid to diacylglycerol to regulate lipid metabolism. Low expression of Lipin1 has been implicated in the severity of cardiac dysfunction in mice. Purpose This study aimed to investigate the role of Lipin1 in the cardiac remodeling after myocardial infarction (MI), revealing its impact on lipid metabolism and molecular pathway associated with cardiac dysfunction. Methods Two types of transgenic mice, cardiomyocyte-specific Lipin1 knockout (cKO) and overexpression (cOE) mice were used in this study. Eight to ten-week-old male mice were subjected to MI by coronary artery ligation. Cardiac lipid droplets were quantified, and triacylglycerol and free fatty acid levels were measured one week after MI surgery. Four weeks after MI, cardiac morphology and function were evaluated using echocardiography, alongside measurements of body weight (BW) and heart weight (HW). Additionally, gene expression analysis and histological evaluation were conducted to assess fatty acid metabolism, cardiac fibrosis, inflammation, and oxidative damage. Results Before MI surgery, there were no differences in HW/BW ratio, left ventricular end-diastolic diameter (LVDd) or LV fractional area change (LVFAC) among cKO/ cOE mice and their littermate controls. After MI, cKO mice exhibited significant cardiac dysfunction with larger LVDd, lower LVFAC and increased HW/BW ratio compared to littermate controls. This was accompanied by exacerbated cardiac fibrosis, increased inflammation, and augmented reactive oxygen species accumulation compared with their controls. Conversely, cOE mice displayed improved LVFAC, reduced cardiac fibrosis, inflammation, and reactive oxygen species accumulation compared to their littermate controls. Notably, the transgene of Lipin1 induced changes in the number of cardiac lipid droplets (LDs). cKO mice hearts showed a reduction in cardiac LDs with decreased levels of triacylglycerol and free fatty acids compared to the littermate controls. In contrast, cOE mice displayed increased cardiac LDs and upregulated expression of fatty acid metabolism–related genes after MI. Conclusion These results suggested that Lipin1 has a protective role against ischemic injury through controlling lipid metabolism in ischemic cardiomyocytes. Thus, Lipin1 emerges as a potential therapeutic target for myocardial infarction.

CHK1 attenuates cardiac dysfunction via suppressing SIRT1-ubiquitination

BackgroundMitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation, however, its role on mitochondrial function in I/R injury remains unknown. MethodsTo investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/overexpression mouse models were generated. Adult mouse cardiomyocytes (AMCMs) were isolated for in vitro study. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism. ResultsCHK1 was downregulated in myocardium post I/R and AMCMs post oxygen-glucose deprivation/re‑oxygenation (OGD/R). In vivo, CHK1 overexpression protected against I/R induced cardiac dysfunction, while heterogenous CHK1 knockout exacerbated cardiomyopathy. In vitro, CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266–390 domain of CHK1 interacted with the 160–583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. The role of CHK1 in maintaining mitochondrial dynamics control and myocardial protection is abolished by SIRT1 inhibition, while inactivated mutation of SIRT1 Thr530 fails to reverse the impaired mitochondrial dynamics following CHK1 knockdown. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown attenuated the protective role of CHK1 in I/R injury. ConclusionsOur findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.

Mechanisms of pathogenicity in the hypertrophic cardiomyopathy-associated TNNI3 c.235C > T variant

BackgroundHypertrophic cardiomyopathy (HCM) is typically manifested as a hereditary disorder, with 30 %–60 % of cases linked to cardiac sarcomere gene mutations. Despite numerous identified TNNI3 mutations associated with HCM, their severity, prevalence, and disease progression vary. The link between TNNI3 variants and phenotypes remains largely unexplored. This study aims to elucidate the impact of the TNNI3 c.235C > T mutation on HCM through clinical research and cell experiments and to explore its mechanism in HCM development. MethodsWe screened an HCM family for pathogenic gene mutations using gene sequencing. The proband and family members were assessed through electrocardiography, echocardiography, and cardiac MRI, and a pedigree map was created for disease prediction analysis. Mutant plasmids were constructed with the TNNI3 c.235C > T mutation and transfected into the AC16 human cardiomyocyte cell line to investigate the mutation's effects. ResultsThe TNNI3 c.235C > T mutation was identified as the disease-causing variant in the family. This mutation led to the upregulation of hypertrophy-associated genes ANP, BNP, and MYH7, increased cardiomyocyte size, and activation of the ERK signaling pathway. Further investigations revealed that the TNNI3 c.235C > T mutation impaired mitochondrial function, disrupted cardiomyocyte metabolism, and increased cellular autophagy and apoptosis. ConclusionsThe TNNI3 c.235C > T gene mutation may be a pathogenic factor for HCM, showing heterogeneous features and clinical phenotypes. This mutation induces myocardial hypertrophy, activates the ERK signaling pathway, and exacerbates mitochondrial dysfunction, apoptosis, and autophagy in cardiomyocytes. These findings provide insights into the mechanism of HCM caused by gene mutations and may inform HCM treatment strategies.

Pyruvate dehydrogenase kinase 1 controls triacylglycerol hydrolysis in cardiomyocytes.

Pyruvate dehydrogenase kinase (PDK) 1 is one of four isozymes that inhibit the oxidative decarboxylation of pyruvate to acetyl-CoA via pyruvate dehydrogenase. PDK activity is elevated in fasting or starvation conditions to conserve carbohydrate reserves. PDK has also been shown to increase mitochondrial fatty acid utilization. In cardiomyocytes, metabolic flexibility is crucial for the fulfillment of high energy requirements. The PDK1 isoform is abundant in cardiomyocytes, but its specific contribution to cardiomyocyte metabolism is unclear. Here we show that PDK1 regulates cardiomyocyte fuel preference by mediating triacylglycerol turnover in differentiated H9c2 myoblasts using lentiviral shRNA to knockdown Pdk1. Somewhat surprisingly, PDK1 loss did not affect overall PDH activity, basal glycolysis, or glucose oxidation revealed by oxygen consumption rate experiments and 13C6 glucose labelling. On the other hand, we observed decreased triacylglycerol turnover in H9c2 cells with PDK1 knockdown, which was accompanied by decreased mitochondrial fatty acid utilization following nutrient deprivation. 13C16 palmitate tracing of uniformly labelled acyl chains revealed minimal acyl chain shuffling within triacylglycerol, indicating that the triacylglycerol hydrolysis, and not re-esterification, was dysfunctional in PDK1 suppressed cells. Importantly, PDK1 loss did not significantly impact the cellular lipidome or triacylglycerol accumulation following palmitic acid treatment, suggesting that effects of PDK1 on lipid metabolism were specific to the nutrient-deprived state. We validated that PDK1 loss decreased triacylglycerol turnover in Pdk1 knockout mice. Together, these findings implicate a novel role for PDK1 in lipid metabolism in cardiomyocytes, independent of its canonical roles in glucose metabolism.

NDRG1 Regulates Iron Metabolism and Inhibits Pathologic Cardiac Hypertrophy

BackgroundCardiac pathologic hypertrophy, a pathologic physiological alteration in many cardiovascular diseases, can progress to heart failure. The cellular biology underlying myocardial hypertrophy remains to be fully elucidated. Although N-myc downstream-regulated gene 1 (NDRG1) has been reported to participate in cellular proliferation, differentiation, and cellular stress responses, its role in cardiac diseases remains unexplored. Here, we investigated the role of NDRG1 in pathologic hypertrophy. MethodCardiomyocyte-specific NDRG1 knockout (KO) transgenic mice and NDRG1-AAV9 were used in mice. Angiotensin II (AngII) stimulation was applied to induce hypertrophy. Histologic, molecular, and RNA-sequencing analyses were performed, and ferroptosis markers and iron levels were studied. We used co-immunoprecipitation (Co-IP) and application of iron chelator to further studied the mechanisms of NDRG1 in cardiac hypertrophy. ResultsWe found that NDRG1 expression is decreased in pathologic hypertrophy induced by AngII stimulation. Conditional KO of NDRG1 in mouse cardiomyocytes led to progressive cardiac hypertrophy and heart failure. Cardiomyocyte-specific overexpression of NDRG1 via AAV9 significantly reversed AngII-induced ventricular hypertrophy and fibrosis. Mechanistically, NDRG1-deficient cardiomyocytes exhibited iron overload and increased ferroptosis, accompanied by elevated levels of reactive oxygen species (ROS) and lipid peroxidation. Subsequently, we confirmed the involvement of NDRG1 in regulating ferroptosis and iron metabolism in myocardial cells. Finally, we identified an interaction between NDRG1 and transferrin in cells. The iron chelator Dp44mT effectively reduced myocardial iron overload and ventricular remodelling induced by NDRG1 deficiency. ConclusionsThese findings highlight critical role of NDRG1 in iron metabolism and ferroptosis in cardiomyocytes, suggesting that NDRG1 or iron metabolism may serve as therapeutic targets for cardiac hypertrophy. Clinical Trial Registration▪▪▪.

Empagliflozin significantly prevents QTc prolongation due to amitriptyline intoxication.

Empagliflozin (EMPA) is a sodium-glucose transporter-2 inhibitor used in the treatment of type 2 diabetes and has positive effects on cardiovascular outcomes. Amitriptyline (AMT) can be used in many clinical indications but leads to cardiotoxicity by causing QT prolongation. Our aim in this study was to determine how the effects of the concomitant use of empagliflozin and amitriptyline, which have been shown to have effects on sodium and calcium metabolism in cardiomyocytes, would cause an effect on QT and QTc intervals in clinical practice. Twenty-four male Wistar albino rats were randomised into four groups. The control group received only physiological serum (1 ml) via orogastric gavage (OG). The EMPA group received empagliflozin (10 mg/kg) via OG. The AMT group received amitriptyline (100 mg/kg) via OG. The AMT + EMPA group (n = 6) received amitriptyline (100 mg/kg) and empagliflozin (10 mg/kg). Under anaesthesia, QT and QTc intervals were measured at baseline, and in the first and second hours. In the AMT group, QT intervals and QTc values were found to be statistically longer than in the control group (p ≤ 0.001). Empagliflozin significantly ameliorated amitriptyline-induced QT and QTc prolongation. In the AMT + EMPA group, QT and QTc intervals were significantly lower compared to that in the AMT group (p < 0.01). In this study, we determined that empagliflozin significantly ameliorated amitriptyline-induced QT and QTc prolongation. This effect was probably due to the opposite effects of these two agents in the intracellular calcium balance. With more clinical trials, the routine use of empagliflozin may be suggested to prevent QT and QTc prolongation in diabetic patients receiving amitriptyline.

Investigation of the profile of dry extracts of Iris hungarica leaves and rhizome to determine the cardioprotective activity in the rat model of doxorubicin cardiomyopathy

The search and creation of new cardioprotective drugs, especially of plant origin, with a prolonged effect and a minimum of side effects, is an urgent task to improve the prognosis of cardiovascular diseases, prevent the risk of developing complications, and increase the duration and quality of life of patients. Iris hungarica, from the Iridaceae family, has a long history of medicinal use in many countries of the world and is also recognized as a rich source of BAC. The aim. Study of the cardioprotective effect of dry extracts of leaves and rhizomes of Iris hungarica on the rat model of doxorubicin cardiomyopathy. Materials and methods. The research was conducted on 40 white outbred female rats, which were injected intraperitoneally with a solution of doxorubicin hydrochloride at a dose of 1 mg/kg, at the rate of 0.5 mL per 100 g of the animal's body weight, according to the scheme 2 times a week for 6 weeks. The cardiotoxic effect and protective properties of potassium orotate, dry extracts of leaves and rhizomes of steppe iris were evaluated by animal survival, determination of the relative heart mass ratio, functional state of the myocardium (ECG parameters) and biochemical parameters in blood serum and heart homogenate. Results and discussion. The analysis of indicators of the functional state of the conducting system of the heart shows that the 15-day use in the treatment of animals with doxorubicin cardiomyopathy of the dry extract of the leaves and rhizomes of Iris hungarica at a dose of 150 mg/kg demonstrates a cardioprotective effect at the initial stage. In the model of doxorubicin cardiomyopathy, the dry extracts of the leaves and rhizomes of steppe iris at a dose of 150 mg/kg showed a normalizing effect on biochemical parameters in blood serum and in heart homogenate and were not inferior to the action of the comparison drug potassium orotate at a dose of 100 mg/kg. The dry extract of the rhizomes of steppe iris revealed the most pronounced effect on metabolism in cardiomyocytes. The cardioprotective activity of the dry extract of the rhizomes of the Iris hungarica is defined as a cardioprotector - of the anabolic and antioxidant type - those that accelerate the recovery of the heart muscle, protect the heart muscle from the action of free radicals, preventing premature aging and wear. Conclusions. In the model of doxorubicin cardiomyopathy in rats, indicators of the functional state of the conducting system of the heart of animals after the use in the treatment of animals of the dry extracts of the leaves and rhizomes of steppe iris in a dose of 150 mg/kg demonstrate a cardioprotective effect at the initial stage, a normalizing effect on biochemical indicators in the blood serum and in the homogenate heart and are not inferior to the comparison drug potassium orotate in a dose of 100 mg/kg. The most pronounced effect of the dry extract of the rhizomes of Iris hungarica on the functional state of the myocardium and biochemical indicators in blood serum and heart homogenate was established. The dry extract of the rhizomes of steppe iris is a promising herbal remedy for the creation of a new drug with cardioprotective properties

Abstract We106: Long Non-Coding RNA LIPTER Regulates Lipid Metabolism of Human Cardiomyocytes and Preserves Cardiac Function

Background: Recently, long non-coding RNAs (lncRNAs) have emerged as novel human-specific (i.e. non-conserved) regulators of cardiovascular development and disease, which possess diverse functions through interacting with other molecules, including DNA, RNA, protein, and lipid. We identified a human lncRNA, LIPTER, which mediates lipid droplet (LD) transport to regulate lipid metabilism of human cardiomyocytes (CMs). Mechanistically, LIPTER binds phospholipids PA and PI4P on the LD membranes and the MYH10 protein, connecting LDs to the cytoskeleton and facilitating LD transport to mitochondria. LIPTER deficiencies led to prominent LD accumulation, mitochondrial dysfunction, and death of human iPS cell-derived CMs. Since downregulation of LIPTER and enahnced LD accumulation are associated with cardiac dysfunction and heart failure in patients with metabolic disorders, such as obesity and diabetes mellitus, we thereby seek to explore the preclinical potential of LIPTER for the therapy of human metabolic disorder associated cardiac dysfunction and heart failure. Hypothesis: We hypothesize that transgenic overexpression of the human lncRNA LIPTER in mouse heart could attenuate metabolic syndrome-associated myocardium lipid accumulation and cardiac dysfunction, as well as prevent isoproterenol-induced heart failure through increasing the fatty acid oxidation (FAO) of mouse heart. Goals: To evaluate the preclinical potential of human lncRNA LIPTER for the therapy of cardiac dysfunction and heart failure by using mouse cardiac dysfunction and heart failure models. Methods: We established a LIPTER transgenic overexpression mouse line (LIPTER Tg ). Both WT and LIPTER Tg mice were fed with high fat diet for 10 months to induce cardiac lipid accumulation and dysfunction. Additionally, heart failure was induced by the chronic isoproterenol administration. After treatment, mice were subjected to histological and molecular analyses. Results: We found LIPTER Tg significantly enhanced FAO of mouse heart, reduced cardiac lipid accumulation and fibrosis, and alleviated cardiac dysfunction of high-fat-diet fed mice, as well as preserved cardiac function of mice post isoproterenol administration. Conclusions: We unveil a crucial role of human lncRNA LIPTER in regulating lipid metabolism of human CMs and testify its clinical potential for treating cardiac dysfunction and heart failure.

Abstract We118: Phosphoglycerate Dehydrogenase Gene Therapy for Dilated Cardiomyopathy

Introduction: Dilated cardiomyopathy (DCM) is a multifaceted cardiac disorder affecting approximately 1 in 250 to 2000 individuals and stands as a predominant cause of heart failure. Despite advancements in identifying genetic mutations associated with DCM, the precise mechanisms driving its pathogenesis are unknown, translating to the lack of disease-modifying interventions. Hypothesis: Modulating serine biosynthesis and one-carbon metabolism in cardiomyocytes by forced expression of Phosphoglycerate Dehydrogenase ( PHGDH) will ameliorate cardiac dysfunction in DCM and halt the disease progression. Methods: We developed a gene therapy vector expressing the PHGDH gene, controlled by a chicken cardiac-specific promoter (cardiac troponin T, cTnT) (AAV9.cTnT.hPHGDH). We delivered this construct via an AAV-based gene transfer approach using the cardiotropic adeno-associated virus serotype-9 in the TM54 DCM mouse – a well-established transgenic mouse that expresses a mutant tropomyosin cDNA (Tpm1 p. E54K; Tm54) under the control of the cardiac αMHC promoter. At 6 weeks old, when the animals exhibit DCM, they were treated with AAV9.cTnT.hPHGDH or control (AAV9.cTnT.GFP). Serial echocardiography was employed to assess heart function for 10 weeks. Morphometric data including heart weight, body weight, and tibia length were recorded. Subsequently, WGA and picrosirius red staining were performed to evaluate cardiomyocyte size and fibrosis, respectively. Finally, metabolic changes were assessed by untargeted metabolomics. Results: AAV9.cTnT.hPHGDH treatment of DCM TM54 mice improved the systolic function and halted the progression of DCM compared to the control mice. Furthermore, PHGDH treatment prevented the development of interstitial fibrosis and cardiomyocyte hypertrophy. Finally, these functional and structural improvements correlate with metabolic rewiring of the glucose metabolism in the DCM heart. Conclusion: These findings suggest that metabolic rewiring of the glucose metabolism by enhancing serine biosynthesis and one-carbon metabolism in the DCM heart may be cardioprotective. Thus, PHGDH gene therapy may be a novel therapeutic approach for DCM and heart failure.

Abstract We097: Dual Targeting CXCR4 and CXCR7 Prevents Doxorubicin-Induced Cardiotoxicity by Eliminating Cardiac Inflammation and Preserving Cardiomyocyte Function

Background: Doxorubicin (DOX)-induced cardiotoxicity (DICT) has become a serious health burden for cancer survivors. The detrimental effects of CXCR4-mediated excessive inflammation in myocardium and the protective effects of CXCR7 in cardiomyocytes have been demonstrated. Aims: We tested the protective effects against DICT of a dual-targeting compound TC14012, which has specific antagonistic activity against CXCR4 and potent agonistic activity on CXCR7. Methods: Eight-week-old male C57BL/6J mice were injected with DOX for consecutive 5 weeks, during which mice were treated with TC14012 twice a week. One week after the last dose injection, mice were euthanized after heart function examination. Markers of cardiac inflammation and fibrosis were evaluated. Cardiac RNA-seq was performed to explore the underlying molecular pathways. Key findings: TC14012 supplement significantly prevented DOX-induced cardiac systolic dysfunction, reflected by improved ejection fraction and fraction shortening, along with remarkable attenuation of DOX-induced cardiac perivascular and interstitial collagen deposition and neutrophils and macrophage infiltration. RNA-seq revealed that TC14012 prevention of DICT was accompanied with a remarkable stimulation of signals involving in cardiac contraction and energy reserve metabolic process, particularly glycogen and glucan metabolism that are crucial for meeting the cardiac energy demand in response to DOX induction. These signals could be further enriched into AMPK signaling pathway and validated by upregulation of AMPK phosphorylation. Besides, TC14012 prevention of DICT was accompanied with a significant reduction in cardiac mast cell activation and degranulation. These signals could be further enriched into Rap1 signaling pathway, and TC14012 was validated to inhibit Rap1 activity and mast cell activation. Most importantly, TC14012 treatment did not affect the suppressive effects of DOX on tumor growth in a syngeneic EL4 lymphoma-bearing, immunocompetent mouse model. Conclusions: We preliminary conclude that TC14012 prevents DICT by activating cardiac CXCR7 to reprogram cardiomyocyte metabolism and prevent cardiac damage and dysfunction via activating AMPK, and by antagonizing CXCR4 to inhibit cardiac mast cell infiltration and activation via blunting Rap1 activity but does not affect the anti-tumor activity of DOX.

Insulin-Heart Axis: Bridging Physiology to Insulin Resistance.

Insulin signaling is vital for regulating cellular metabolism, growth, and survival pathways, particularly in tissues such as adipose, skeletal muscle, liver, and brain. Its role in the heart, however, is less well-explored. The heart, requiring significant ATP to fuel its contractile machinery, relies on insulin signaling to manage myocardial substrate supply and directly affect cardiac muscle metabolism. This review investigates the insulin-heart axis, focusing on insulin's multifaceted influence on cardiac function, from metabolic regulation to the development of physiological cardiac hypertrophy. A central theme of this review is the pathophysiology of insulin resistance and its profound implications for cardiac health. We discuss the intricate molecular mechanisms by which insulin signaling modulates glucose and fatty acid metabolism in cardiomyocytes, emphasizing its pivotal role in maintaining cardiac energy homeostasis. Insulin resistance disrupts these processes, leading to significant cardiac metabolic disturbances, autonomic dysfunction, subcellular signaling abnormalities, and activation of the renin-angiotensin-aldosterone system. These factors collectively contribute to the progression of diabetic cardiomyopathy and other cardiovascular diseases. Insulin resistance is linked to hypertrophy, fibrosis, diastolic dysfunction, and systolic heart failure, exacerbating the risk of coronary artery disease and heart failure. Understanding the insulin-heart axis is crucial for developing therapeutic strategies to mitigate the cardiovascular complications associated with insulin resistance and diabetes.

Oxidative Stress and Mitochondria Are Involved in Anaphylaxis and Mast Cell Degranulation: A Systematic Review.

Anaphylaxis, an allergic reaction caused by the massive release of active mediators, can lead to anaphylactic shock (AS), the most severe and potentially life-threatening form of anaphylactic reaction. Nevertheless, understanding of its pathophysiology to support new therapies still needs to be improved. We performed a systematic review, assessing the role and the complex cellular interplay of mitochondria and oxidative stress during anaphylaxis, mast cell metabolism and degranulation. After presenting the main characteristics of anaphylaxis, the oxidant/antioxidant balance and mitochondrial functions, we focused this review on the involvement of mitochondria and oxidative stress in anaphylaxis. Then, we discussed the role of oxidative stress and mitochondria following mast cell stimulation by allergens, leading to degranulation, in order to further elucidate mechanistic pathways. Finally, we considered potential therapeutic interventions implementing these findings for the treatment of anaphylaxis. Experimental studies evaluated mainly cardiomyocyte metabolism during AS. Cardiac dysfunction was associated with left ventricle mitochondrial impairment and lipid peroxidation. Studies evaluating in vitro mast cell degranulation, following Immunoglobulin E (IgE) or non-IgE stimulation, revealed that mitochondrial respiratory complex integrity and membrane potential are crucial for mast cell degranulation. Antigen stimulation raises reactive oxygen species (ROS) production from nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and mitochondria, leading to mast cell degranulation. Moreover, mast cell activation involved mitochondrial morphological changes and mitochondrial translocation to the cell surface near exocytosis sites. Interestingly, antioxidant administration reduced degranulation by lowering ROS levels. Altogether, these results highlight the crucial role of oxidative stress and mitochondria during anaphylaxis and mast cell degranulation. New therapeutics against anaphylaxis should probably target oxidative stress and mitochondria, in order to decrease anaphylaxis-induced systemic and major organ deleterious effects.