Pharmacological Modulation of Cardiac Remodeling after Myocardial Infarction

Activation of NFE2L2 Alleviates Endoplasmic Reticulum Stress-Mediated Pyroptosis in Murine Hippocampus: A Bioinformatics Analysis and Experimental Validation

Pyroptosis has been implicated in many pathologic processes, including endoplasmic reticulum stress (ERS). However, the underlying mechanisms and molecular targets of ERS affecting pyroptosis still need further exploration. We obtained gene sets associated with ERS and pyroptosis, and the common genes were regarded as crosstalk genes linking ERS and pyroptosis. Protein-protein interaction (PPI) network was constructed, and the hub genes were obtained via Cytoscape. Moreover, to validate the efficacy of the therapeutic target, neurological tests, brain water content measurements, Nissl staining, Western blot, ELISA, TUNEL analyses, and transmission electron microscopy were performed in a mouse model. A total of 13 crosstalk genes were acquired, and enrichment analysis revealed that these genes were mainly enriched in stress-associated cellular processes and pathways, including KEAP1-NFE2L2 pathway. The hub gene, NFE2L2, was identified by Cytoscape, and tert-butylhydroquinone (tBHQ) was screened as candidate drug to activate NFE2L2. Western blot and ELISA results showed that activation of NFE2L2 could attenuate the expression of ERS and pyroptosis-related proteins by promoting nuclear translocation of Nrf2 (encoded by NFE2L2). Pathological evaluation by Nissl staining and TUNEL assay reflected a similar trend. Furthermore, activation of NFE2L2 ameliorated neurological deficits and reduced brain edema. In conclusion, our bioinformatic analysis results established the theoretical foundation of NFE2L2 as a promising therapeutic target. Moreover, in the mouse model, tBHQ pretreatment further confirmed the effectiveness of this target. We hypothesized NFE2L2 may play a key role in the progression of ERS-mediated pyroptosis. These findings may inspire new ideas to treat neurological disorders.

[Xionggui Decoction alleviates heart failure in mice with myocardial infarction by inhibiting oxidative stress-induced cardiomyocyte apoptosis]

OBJECTIVE

To explore the protective effect of Xionggui Decoction against cardiac myopathy in a mouse model of heart failure following myocardial infarction (MI) and explore the underlying mechanism.

METHODS

We searched TCMSP, GeneCards, and CTD databases for the targets of active ingredients Xionggui Decoction and heart failure, and the intersecting targets were analyzed with GO and KEGG pathway enrichment analysis using DAVID database. In a mouse model of heart failure following acute MI induced by coronary artery ligation, the cardiac protective effects of 3 g/kg Xionggui Decoction were evaluated by assessing cardiac function, cardiac myopathy and ventricular remodeling of the mice using HE staining, Masson staining, RT-qPCR, and immunohistochemistry. We also tested the effect of Xionggui Decoction at 50 and 100 μg/mL on tertbutylhydrogen peroxide (TBHP)-induced apoptosis of H9C2 cells using CCK8 assay, detection kits for ROS, MDA, SOD, JC-1 and Hoechst 33342/PI staining.

RESULTS

Network pharmacological analysis identified 62 potential targets of Xionggui Decoction for treatment of heart failure, and the core targets included PTGS2, ESR1, caspase-3, PPARG, HSP90AA1, BCL2, JUN, and GSK3B, which were involved in cell apoptosis and the AGE-RAGE, P53, PI3K-Akt, and VEGF signaling pathways. In the mouse models of heart failure, treatment with Xionggui Decoction significantly alleviated cardiac myopathy and ventricular remodeling, obviously improved heart function of the mice, lowered myocardial expressions of caspase-3 and BAX, and enhanced the expression of BCL2. In H9C2 cells, Xionggui Decoction significantly alleviated TBHP-induced cell apoptosis by inhibiting oxidative stress in the cells.

CONCLUSION

Xionggui Decoction can alleviate myocardial injury and improve cardiac function in mice with heart failure following acute MI possibly by inhibiting cardiomyocyte apoptosis induced by oxidative stress.

The role of oral metformin in preventing and treating age-related macular degeneration: A meta-analysis

BACKGROUND

We aimed to perform a meta-analysis to evaluate the effect of metformin on age-related macular degeneration.

METHODS

We searched the following databases: PubMed, Scopus, and Web of Science. We included any randomized control trials, prospective and retrospective cohorts, cross-sectional studies, and case-control studies that investigated the effect of metformin on age-related macular degeneration in our meta-analysis with no age or language restrictions. Review manager software, version 5.4 was used to perform the meta-analysis.

RESULTS

Ten studies were included in the meta-analysis with 1,447,470 patients included in the analysis. The pooled analysis showed no statistically significant difference between the metformin group and the non-metformin group regarding age-related macular degeneration (odds ratio [OR] = 0.37, confidence interval [CI] = (0.14-1.02), P = .05). Subgroup analysis showed no statistically significant difference between metformin group and non-metformin group regarding age-related macular degeneration in present or past metformin usage (OR = 0.19, CI = (0.03-1.1), P = .06), (OR = 0.61, CI = (0.25-1.45), P = .26), respectively, The pooled analysis showed no statistically significant difference between age-related macular degeneration group and control group regarding metformin usage (OR = 0.86, CI = (0.74-1.00), P = .05). The subgroup analysis showed no statistically significant difference between the age-related macular degeneration group and control group in <2 years of metformin usage and 2 years or more (OR = 0.89, CI = (0.52-1.52), P = .67), (OR = 0.95, CI = (0.82-1.10), P = .47), respectively.

CONCLUSION

Our study revealed no role of metformin in decreasing age-related macular degeneration risk in past or present usage. More RCTs are needed to support our findings in evaluating the actual role of metformin in age-related macular degeneration.

Antifibrotic effect of the P2X7 receptor antagonist A740003 against acute myocardial infarction-induced fibrotic remodelling

Post-acute myocardial infarction (AMI) fibrosis is a pathophysiologic process characterised by activation of the profibrotic mediator, transforming growth factor-β (TGF-β). AMI is associated with a substantial increase in the levels of extracellular adenosine triphosphate (eATP), which acts on the purinergic P2X7-receptor (P2X7-R) and triggers an inflammatory response that contributes to myocardial fibrotic remodelling. P2X7-R has been implicated in several cardiovascular diseases; however, its role in the regulation of cardiac fibrosis remains unclear. Therefore, the current study aimed to determine the effect of the P2X7-R antagonist, A740003, on post-AMI fibrosis, via the profibrotic TGF-β1/Smad signalling pathway, and elucidate whether its effect is mediated via the modulation of GSK-3β. AMI was induced by surgical ligation of the left anterior descending coronary artery, Thereafter, animals were divided into groups: sham control, MI-untreated, MI-vehicle, and MI-A740003 (50 mg/kg/day) and treated for seven days accordingly. The heart weight/body weight ratio of untreated-ligated rats significantly increased by 15.1 %, creatine kinase-MB (CK-MB) significantly increased by 40 %, troponin-I levels significantly increased by 25.4 %, and lactate dehydrogenase significantly increased by 47.2 %, indicating myocardial damage confirmed by morphological changes and massive cardiac fibrosis. The protein expression of cardiac fibronectin, TGF-β1, and p-Smad2 were also upregulated by 143 %, 40 %, and 8 %, respectively, indicating cardiac fibrosis. The treatment of ligated rats with A740003 led to improvement in all the above-mentioned parameters. Overall, A740003 exhibits potential cardio-protective effects on post-AMI fibrotic remodelling in the animal model of AMI through P2X7-R blockade, possibly by downregulating the profibrotic TGF-β1/Smad signalling pathway and restoring GSK-3β phosphorylation. Altogether, treatment with A740003 could serve as a new cardioprotective strategy to attenuate post-AMI fibrotic remodelling.

Acute sleep deprivation (ASD) and cardioprotection: Impact of ASD on oxytocin-mediated sympathetic nervous activation preceding myocardial infarction

INTRODUCTION

This study explored how acute sleep deprivation (ASD) before myocardial ischemia influences oxytocin release from paraventricular (PVN) neurons and its correlation with sympathetic nervous system (SNS) activity post-acute sleep loss, impacting subsequent left ventricular (LV) remodeling following myocardial infarction (MI).

METHODS

The study was conducted in two phases: induction of ASD, inducing MI, blood sampling, euthanizing animals and collecting their heart and brain for histological and gene expression evaluations. The animals in first and second phase were euthanized 24 h and 14 days after MI, respectively.

RESULTS

Pre-MI ASD, accompanied by increased serum epinephrine levels within 24 h of MI, upregulated oxytocin and cFos expression in the PVN. Also, pre-MI ASD resulted in decreased serum PAB levels 14 days post-MI (P < 0.001). While notable echocardiographic changes were seen in MI versus sham groups, ASD demonstrated protective effects. This was evidenced by reduced infarct size, elevated TIMP1, MMP2, and MMP9 in the LV of SD + MI animals versus MI alone (P < 0.05). Additionally, histological analysis showed reduced LV fibrosis in pre-MI ASD subjects (P < 0.05).

CONCLUSION

Our study supports the notion that activation of oxytocin neurons within the PVN subsequent to ASD interacts with autonomic centers in the central nervous system. This enhanced sympathetic outflow to the heart prior to MI triggers a preconditioning response, thereby mediating cardioprotection through decreased oxidative stress biomarkers and regulated extracellular matrix (ECM) turnover.

Annexin A1-Loaded Alginate Hydrogel Promotes Cardiac Repair via Modulation of Macrophage Phenotypes after Myocardial Infarction

Myocardial infarction (MI) is associated with inflammatory reaction, which is a pivotal component in MI pathogenesis. Moreover, excessive inflammation post-MI can lead to cardiac dysfunction and adverse remodeling, emphasizing the critical need for an effective inflammation-regulating treatment for cardiac repair. Macrophage polarization is crucial in the inflammation process, indicating its potential as an adjunct therapy for MI. In this study, we developed an injectable alginate hydrogel loaded with annexin A1 (AnxA1, an endogenous anti-inflammatory and pro-resolving mediator) for MI treatment. In vitro results showed that the composite hydrogel had good biocompatibility and consistently released AnxA1 for several days. Additionally, this hydrogel led to a reduced number of pro-inflammatory macrophages and an increased proportion of pro-healing macrophages via the adenosine monophosphate (AMP)-activated protein kinase (AMPK)-mammalian target of the rapamycin (mTOR) axis. Furthermore, the intramyocardial injection of this composite hydrogel into a mouse MI model effectively modulated macrophage transition to pro-healing phenotypes. This transition mitigated early inflammatory responses and cardiac fibrosis, promoted angiogenesis, and improved cardiac function. Therefore, our study findings suggest that combining biomaterials and endogenous proteins for MI treatment is a promising approach for limiting adverse cardiac remodeling, preventing cardiac damage, and preserving the function of infarcted hearts.

Role of long noncoding RNAs in pathological cardiac remodeling after myocardial infarction: An emerging insight into molecular mechanisms and therapeutic potential

Myocardial infarction (MI) is the leading cause of heart failure (HF), accounting for high mortality and morbidity worldwide. As a consequence of ischemia/reperfusion injury during MI, multiple cellular processes such as oxidative stress-induced damage, cardiomyocyte death, and inflammatory responses occur. In the next stage, the proliferation and activation of cardiac fibroblasts results in myocardial fibrosis and HF progression. Therefore, developing a novel therapeutic strategy is urgently warranted to restrict the progression of pathological cardiac remodeling. Recently, targeting long non-coding RNAs (lncRNAs) provided a novel insight into treating several disorders. In this regard, numerous investigations have indicated that several lncRNAs could participate in the pathogenesis of MI-induced cardiac remodeling, suggesting their potential therapeutic applications. In this review, we summarized lncRNAs displayed in the pathophysiology of cardiac remodeling after MI, emphasizing molecular mechanisms. Also, we highlighted the possible translational role of lncRNAs as therapeutic targets for this condition and discussed the potential role of exosomes in delivering the lncRNAs involved in post-MI cardiac remodeling.

KATP channels are regulators of programmed cell death and targets for the creation of novel drugs against ischemia/reperfusion cardiac injury

BACKGROUND

The use of percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is associated with a mortality rate of 5%-7%. It is clear that there is an urgent need to develop new drugs that can effectively prevent cardiac reperfusion injury. ATP-sensitive K+ (KATP ) channel openers (KCOs) can be classified as such drugs.

RESULTS

KCOs prevent irreversible ischemia and reperfusion injury of the heart. KATP channel opening promotes inhibition of apoptosis, necroptosis, pyroptosis, and stimulation of autophagy. KCOs prevent the development of cardiac adverse remodeling and improve cardiac contractility in reperfusion. KCOs exhibit antiarrhythmic properties and prevent the appearance of the no-reflow phenomenon in animals with coronary artery occlusion and reperfusion. Diabetes mellitus and a cholesterol-enriched diet abolish the cardioprotective effect of KCOs. Nicorandil, a KCO, attenuates major adverse cardiovascular event and the no-reflow phenomenon, reduces infarct size, and decreases the incidence of ventricular arrhythmias in patients with acute myocardial infarction.

CONCLUSION

The cardioprotective effect of KCOs is mediated by the opening of mitochondrial KATP (mitoKATP ) and sarcolemmal KATP (sarcKATP ) channels, triggered free radicals' production, and kinase activation.

Chloroquine enhances the efficacy of chemotherapy drugs against acute myeloid leukemia by inactivating the autophagy pathway

Current therapy for acute myeloid leukemia (AML) is largely hindered by the development of drug resistance of commonly used chemotherapy drugs, including cytarabine, daunorubicin, and idarubicin. In this study, we investigated the molecular mechanisms underlying the chemotherapy drug resistance and potential strategy to improve the efficacy of these drugs against AML. By analyzing data from ex vivo drug-response and multi-omics profiling public data for AML, we identified autophagy activation as a potential target in chemotherapy-resistant patients. In THP-1 and MV-4-11 cell lines, knockdown of autophagy-regulated genes ATG5 or MAP1LC3B significantly enhanced AML cell sensitivity to the chemotherapy drugs cytarabine, daunorubicin, and idarubicin. In silico screening, we found that chloroquine phosphate mimicked autophagy inactivation. We showed that chloroquine phosphate dose-dependently down-regulated the autophagy pathway in MV-4-11 cells. Furthermore, chloroquine phosphate exerted a synergistic antitumor effect with the chemotherapy drugs in vitro and in vivo. These results highlight autophagy activation as a drug resistance mechanism and the combination therapy of chloroquine phosphate and chemotherapy drugs can enhance anti-AML efficacy.

Engineering of MSCs sheet for the prevention of myocardial ischemia and for left ventricle remodeling

Tissue engineering combines cell biology and material science to construct tissues or organs for disease modeling, drug testing, and regenerative medicine. The cell sheet is a newly developed tissue engineering technology that has brought about scaffold-free tissue and shows great application potential. In this review, we summarized recent progress and future possibilities in preclinical research into and clinical applications of cell sheets fabricated by differing cell types from various sources for cardiac tissue repair, and the manufacturing strategies and promising application potential of 3D cell-dense tissue constructed from cell sheets. Special attention was paid to the mechanisms of mesenchymal stem cell (MSC) sheets in the prevention of myocardial ischemia and left ventricle remodeling. Comparing MSCs sheets with other types of cell sheets and 3D cardiac tissues, engineering tissues' potential safety and effectiveness concerns were also discussed.

PPAR Alpha Activation by Clofibrate Alleviates Ischemia/Reperfusion Injury in Metabolic Syndrome Rats by Decreasing Cardiac Inflammation and Remodeling and by Regulating the Atrial Natriuretic Peptide Compensatory Response

Metabolic syndrome (MetS) is a cluster of factors that increase the risk of developing diabetes, stroke, and heart failure. The pathophysiology of injury by ischemia/reperfusion (I/R) is highly complex and the inflammatory condition plays an important role by increasing matrix remodeling and cardiac apoptosis. Natriuretic peptides (NPs) are cardiac hormones with numerous beneficial effects mainly mediated by a cell surface receptor named atrial natriuretic peptide receptor (ANPr). Although NPs are powerful clinical markers of cardiac failure, their role in I/R is still controversial. Peroxisome proliferator-activated receptor α agonists exert cardiovascular therapeutic actions; however, their effect on the NPs’ signaling pathway has not been extensively studied. Our study provides important insight into the regulation of both ANP and ANPr in the hearts of MetS rats and their association with the inflammatory conditions caused by damage from I/R. Moreover, we show that pre-treatment with clofibrate was able to decrease the inflammatory response that, in turn, decreases myocardial fibrosis, the expression of metalloprotease 2 and apoptosis. Treatment with clofibrate is also associated with a decrease in ANP and ANPr expression.

Endothelial-cell-mediated mechanism of coronary microvascular dysfunction leading to heart failure with preserved ejection fraction

Although the prevalence of heart failure with preserved ejection fraction (HFpEF) is growing worldwide, its complex pathophysiology has yet to be fully elucidated, and multiple hypotheses have all failed to produce a viable target for therapeutic action or provide effective treatment. Cardiac remodeling has long been considered an important mechanism of HFpEF. Strong evidence has been reported over the past years that coronary microvascular dysfunction (CMD), manifesting as structural and functional abnormalities of coronary microvasculature, also contributes to the evolution of HFpEF. However, the mechanisms of CMD are still not well understood and need to be studied further. Coronary microvascular endothelial cells (CMECs) are one of the most abundant cell types in the heart by number and active players in cardiac physiology and pathology. CMECs are not only important cellular mediators of cardiac vascularization but also play an important role in disease pathophysiology by participating in the inception and progression of cardiac remodeling. CMECs are also actively involved in the pathogenesis of CMD. Numerous studies have confirmed that CMD is closely related to cardiac remodeling. ECs may serve a critical function in mediating the connection between CMD and HFpEF. It follows that CMECs participate in the mechanism of CMD leading to HFpEF. In this review article, we focus on the role of CMD in the pathogenesis of HFpEF resulting from cardiac remodeling and highlight the subsequent complexity of the EC-mediated correlation between CMD and HFpEF.

Three-dimensional echocardiographic assessment of left ventricular geometric changes following acute myocardial infarction

Acute ST-segment elevation myocardial infarction (STEMI) is associated with left ventricular (LV) structural and functional consequences. We aimed to elucidate LV geometric changes following STEMI using three-dimensional (3D) echocardiography (3DE) and to assess their functional implications using two-dimensional (2D) speckle tracking echocardiography (STE). The study included 71 patients with STEMI who underwent baseline and 6-month follow-up 2D- and 3DE. Measured parameters included LV dimensions, biplane volumes, wall motion assessment, 2D LV global longitudinal strain (GLS), and 3D LV volumes, sphericity index and systolic dyssynchrony index. According to 3DE, LV geometric changes were classified as, adverse remodeling, reverse remodeling, and minimal LV volumetric changes. The occurrence of in-hospital and follow-up major adverse cardiovascular events (MACE) was assessed among the study population. The incidence of developing adverse remodeling was 25.4% while that of reverse remodeling was 36.6%. Adverse remodeling patients had significantly higher in-hospital MACE. Reverse remodeling was associated with significantly improved GLS, that was less evident in those with minimal LV geometric changes, and non-significant improvement for adverse remodeling group. LV baseline 2D GLS significantly correlated with follow-up 3D volumes among both reverse and adverse remodeling groups. Female gender and higher absolute GLS change upon follow-up were significantly associated with reverse remodeling. ROC-derived cutoff for adverse remodeling reallocated a substantial number of patients from the minimal change group to the adverse remodeling. Following acute STEMI, two-dimensional GLS was associated with and potentially predictive of changes in LV volumes as detected by three-dimensional echocardiography.

Extracellular vesicles mediate biological information delivery: A double-edged sword in cardiac remodeling after myocardial infarction

Acute myocardial infarction (AMI) is a severe ischemic disease with high morbidity and mortality worldwide. Maladaptive cardiac remodeling is a series of abnormalities in cardiac structure and function that occurs following myocardial infarction (MI). The pathophysiology of this process can be separated into two distinct phases: the initial inflammatory response, and the subsequent longer-term scar revision that includes the regression of inflammation, neovascularization, and fibrotic scar formation. Extracellular vesicles are nano-sized lipid bilayer vesicles released into the extracellular environment by eukaryotic cells, containing bioinformatic transmitters which are essential mediators of intercellular communication. EVs of different cellular origins play an essential role in cardiac remodeling after myocardial infarction. In this review, we first introduce the pathophysiology of post-infarction cardiac remodeling, as well as the biogenesis, classification, delivery, and functions of EVs. Then, we explore the dual role of these small molecule transmitters delivered by EVs in post-infarction cardiac remodeling, including the double-edged sword of pro-and anti-inflammation, and pro-and anti-fibrosis, which is significant for post-infarction cardiac repair. Finally, we discuss the pharmacological and engineered targeting of EVs for promoting heart repair after MI, thus revealing the potential value of targeted modulation of EVs and its use as a drug delivery vehicle in the therapeutic process of post-infarction cardiac remodeling.

The emerging importance of immunophilins in fibrosis development

Immunophilins are a family of proteins encompassing FK506-binding proteins (FKBPs) and cyclophilins (Cyps). FKBPs and Cyps exert peptidyl-prolyl cis-trans isomerase (PPIase) activity, which facilitates diverse protein folding assembly, or disassembly. In addition, they bind to immunosuppressant medications where FKBPs bind to tacrolimus (FK506) and rapamycin, whereas cyclophilins bind to cyclosporin. Some large immunophilins have domains other than PPIase referred to as tetratricopeptide (TPR) domain, which is involved in heat shock protein 90 (Hsp90) and heat shock protein 70 (Hsp 70) chaperone interaction. The TPR domain confers immunophilins’ pleotropic actions to mediate various physiological and biochemical processes. So far, immunophilins have been implicated to play an important role in pathophysiology of inflammation, cancer and neurodegenerative disorders. However, their importance in the development of fibrosis has not yet been elucidated. In this review we focus on the pivotal functional and mechanistic roles of different immunophilins in fibrosis establishment affecting various organs. The vast majority of the studies reported that cyclophilin A, FKBP12 and FKBP10 likely induce organ fibrosis through the calcineurin or TGF-β pathways. FKBP51 demonstrated a role in myelofibrosis development through calcineurin-dependant pathway, STAT5 or NF-κB pathways. Inhibition of these specific immunophilins has been shown to decrease the extent of fibrosis suggesting that immunophilins could be a novel promising therapeutic target to prevent or reverse fibrosis.

Plasma metabolomics provides new insights into the relationship between metabolites and outcomes and left ventricular remodeling of coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a metabolically perturbed pathological condition. However, the knowledge of metabolic signatures on outcomes of CAD and their potential causal effects and impacts on left ventricular remodeling remains limited. We aim to assess the contribution of plasma metabolites to the risk of death and major adverse cardiovascular events (MACE) as well as left ventricular remodeling.

RESULTS

In a prospective study with 1606 Chinese patients with CAD, we have identified and validated several independent metabolic signatures through widely-targeted metabolomics. The predictive model respectively integrating four metabolic signatures (dulcitol, β-pseudouridine, 3,3',5-Triiodo-L-thyronine, and kynurenine) for death (AUC of 83.7% vs. 76.6%, positive IDI of 0.096) and metabolic signatures (kynurenine, lysoPC 20:2, 5-methyluridine, and L-tryptophan) for MACE (AUC of 67.4% vs. 59.8%, IDI of 0.068) yielded better predictive value than trimethylamine N-oxide plus clinical model, which were successfully applied to predict patients with high risks of death (P = 0.0014) and MACE (P = 0.0008) in the multicenter validation cohort. Mendelian randomisation analysis showed that 11 genetically inferred metabolic signatures were significantly associated with risks of death or MACE, such as 4-acetamidobutyric acid, phenylacetyl-L-glutamine, tryptophan metabolites (kynurenine, kynurenic acid), and modified nucleosides (β-pseudouridine, 2-(dimethylamino) guanosine). Mediation analyses show that the association of these metabolites with the outcomes could be partly explained by their roles in promoting left ventricular dysfunction.

CONCLUSIONS

This study provided new insights into the relationship between plasma metabolites and clinical outcomes and its intermediate pathological process left ventricular dysfunction in CAD. The predictive model integrating metabolites can help to improve the risk stratification for death and MACE in CAD. The metabolic signatures appear to increase death or MACE risks partly by promoting adverse left ventricular dysfunction, supporting potential therapeutic targets of CAD for further investigation.

Calycosin reduces myocardial fibrosis and improves cardiac function in post-myocardial infarction mice by suppressing TGFBR1 signaling pathways

BACKGROUND

Excessive myocardial fibrosis is the pathological basis of heart failure following myocardial infarction (MI). Although calycosin improves cardiac function, its effect on cardiac fibrosis and cardiac function after MI in mice and its precise mechanism remain unclear.

PURPOSE

Here, we firstly investigated the effects of calycosin on cardiac fibrosis and ventricular function in mice after MI and the role of transforming growth factor-beta receptor 1 (TGFBR1) signaling in the amelioration of cardiac fibrosis and ventricular function.

METHODS

In vivo effects of calycosin on cardiac structure and function in mice with MI induced by left anterior descending coronary artery ligation were determined by hematoxylin and eosin staining, Masson trichrome staining, and echocardiography. The molecular mechanism of the interaction between TGFBR1 and calycosin was investigated using molecular docking, molecular dynamics (MD) simulation, surface plasmon resonance imaging (SPRi), immunohistochemistry, and western blotting (WB). Subsequently, cardiac-specific Tgfbr1 knockout mice were used to verify the effects of calycosin. The effect of calycosin on primary cardiac fibroblasts (CFs) proliferation and collagen deposition was detected using cell counting (CCK-8), EdU assay, and WB in vitro. CFs infected with an adenovirus that encodes TGFBR1 were used to verify the effects of calycosin.

RESULTS

In vivo, calycosin attenuated myocardial fibrosis and cardiac dysfunction following MI in a dose-dependent pattern. Calycosin-TGFBR1 complex was found to have a binding energy of -9.04 kcal/mol based on molecular docking. In addition, calycosin bound steadily in the cavity of TGFBR1 during the MD simulation. Based on SPRi results, the solution equilibrium dissociation constant for calycosin and TGFBR1 was 5.11 × 10^-5 M. Calycosin inhibited the expression of TGFBR1, Smad2/3, collagen I, and collagen III. The deletion of TGFBR1 partially counteracted these effects. In vitro, calycosin suppressed CFs proliferation and collagen deposition after TGF-β1 stimulation by suppressing the TGFBR1 signaling pathway. The suppressive effects of calycosin were partially rescued by overexpression of TGFBR1.

CONCLUSION

Calycosin attenuates myocardial fibrosis and cardiac dysfunction following MI in mice in vivo via suppressing the TGFBR1 signaling pathway. Calycosin suppresses CFs proliferation and collagen deposition induced by TGF-β1 via inhibition of the TGFBR1 signaling pathway in vitro.

Hyaluronan Synthase 3 is Protective After Cardiac Ischemia-Reperfusion by preserving the T cell Response

Dysregulated extracellular matrix (ECM) is a hallmark of adverse cardiac remodeling after myocardial infarction (MI). Previous work from our laboratory suggests that synthesis of the major ECM component hyaluronan (HA) may be beneficial for post-infarct healing. Here, we aimed to investigate the mechanisms of hyaluronan synthase 3 (HAS3) in cardiac healing after MI. Mice with genetic deletion of Has3 (Has3 KO) and wildtype mice (WT) underwent 45 minutes of ischemia with subsequent reperfusion (I/R), followed by monitoring of heart function and analysis of tissue remodeling for up to three weeks. Has3 KO mice exhibited impaired cardiac function as evidenced by a reduced ejection fraction. Accordingly, Has3 deficiency also resulted in an increased scar size. Cardiac fibroblast activation and CD68⁺ macrophage counts were similar between genotypes. However, we found a significant decrease in CD4 T cells in the hearts of Has3 KO mice seven days post-MI, in particular reduced numbers of CD4⁺CXCR3⁺ Th1 and CD4⁺CD25⁺ Treg cells. Furthermore, Has3 deficient cardiac T cells were less activated and more apoptotic as shown by decreased CD69⁺ and increased annexin V⁺ cells, respectively. In vitro assays using activated splenic CD3 T cells demonstrated that Has3 deficiency resulted in reduced expression of the main HA receptor CD44 and diminished T cell proliferation. T cell transendothelial migration was similar between genotypes. Of note, analysis of peripheral blood from patients with ST-elevation myocardial infarction (STEMI) revealed that HAS3 is the predominant HAS isoenzyme also in human T cells. In conclusion, our data suggest that HAS3 is required for mounting a physiological T cell response after MI to support cardiac healing. Therefore, our study may serve as a foundation for the development of novel strategies targeting HA-matrix to preserve T cell function after MI.

Left Ventricular Remodeling after Myocardial Infarction: From Physiopathology to Treatment

Myocardial infarction (MI) is the leading cause of death and morbidity worldwide, with an incidence relatively high in developed countries and rapidly growing in developing countries. The most common cause of MI is the rupture of an atherosclerotic plaque with subsequent thrombotic occlusion in the coronary circulation. This causes cardiomyocyte death and myocardial necrosis, with subsequent inflammation and fibrosis. Current therapies aim to restore coronary flow by thrombus dissolution with pharmaceutical treatment and/or intravascular stent implantation and to counteract neurohormonal activation. Despite these therapies, the injury caused by myocardial ischemia leads to left ventricular remodeling; this process involves changes in cardiac geometry, dimension and function and eventually progression to heart failure (HF). This review describes the pathophysiological mechanism that leads to cardiac remodeling and the therapeutic strategies with a role in slowing the progression of remodeling and improving cardiac structure and function.

Nerve growth factor and post-infarction cardiac remodeling

The prevalence of sudden death from chronic heart failure and cardiac arrhythmias caused by myocardial infarction is a complex problem in cardiology. Post-infarction cardiac remodeling occurs after myocardial infarction. This compensatory-adaptive reaction, regulated by mechanical, neurohumoral and genetic factors, includes the structural and functional changes of cardiomyocytes, stromal elements and extracellular matrix, geometry and architectonics of the left ventricular cavity. Adverse left ventricular remodeling is associated with heart failure and increased mortality. The concept of post-infarction cardiac remodeling is an urgent problem, since the mechanisms of development and progression of adverse post-infarction changes in the myocardium are completely unexplored. In recent years, the scientist attention has been focused on neurotrophic factors involved in the sympathetic nervous system and the vascular system remodeling after myocardial infarction. Nerve growth factor (NGF) is a protein from the neurotrophin family that is essential for the survival and development of sympathetic and sensory neurons, which also plays an important role in vasculogenesis. Acute myocardial infarction and heart failure are characterized by changes in the expression and activity of neurotrophic factors and their receptors, affecting the innervation of the heart muscle, as well as having a direct effect on cardiomyocytes, endothelial and smooth muscle vascular cells. The identification of the molecular mechanisms involved in the interactions between cardiomyocytes and neurons, as well as the study of the effects of NGF in the cardiovascular system, will improve understanding of the cardiac remodeling mechanism. This review summarizes the available scientific information (2019–2021) about mechanisms of the link between post-infarction cardiac remodeling and NGF functions.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Formation and occurrence of disinfection byproducts of benzodiazepine drug estazolam in drinking water of Beijing

Estazolam (EZ) is a long-acting benzodiazepine (BZD) drug with high clinical consumption in China to treat anxiety, depression and other syndromes. Recently, it has been found as a leading potentially inappropriate medication among hospitalized elderly patients, increasing the risk of falls. It is discharged into the aquatic environment after use and has been frequently detected, ultimately affecting the safety of drinking water. In the present study, the reaction of EZ during chlorination disinfection was investigated in detail with regard to its transformation and kinetics. By means of ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS), four main disinfection byproducts (DBPs) were tentatively identified, and the transformation pathways were speculated to be cleavage at the imine linkage and oxidation on the diazepinone ring. The chlorination reaction rate in the pseudo-first-order kinetic model was significantly affected by free available chlorine (FAC) and pH. The increase in pH value led to a decrease in the reaction rate, while a higher dosage of chlorine resulted in a faster kinetic rate. We further estimated the potential toxicities of EZ and its DBPs using quantitative structure-activity relationship (QSAR) software tools. DBPs exhibited much higher toxicity than EZ and exhibited developmental toxicity and mutagenicity. Finally, a total of 108 drinking water samples were collected in the wet and dry seasons to determine actual residue changes in real environmental conditions. The detection frequency was 29% for EZ, and the highest concentration of 0.60 ng L^-1 was found for its DBPs in tap water. No seasonal variations in concentration were observed. Overall, the results indicate that EZ and its DBPs may persist in drinking water, posing potential risks to public health.

Distribution visualization of the chlorinated disinfection byproduct of diazepam in zebrafish with desorption electrospray ionization mass spectrometry imaging

Diazepam (DZP) was routinely prescribed to a large population troubled with anxiety disorders. However, due to the overuse and misuse, DZP and its chlorination disinfection byproduct 2-methylamino-5-chlorobenzophenone (MACB) caused environmental pollution and can be detected ubiquitously in drinking water in Beijing, China. However, little information is known about the metabolic dynamics of MACB. Here, we established desorption electrospray ionization mass spectrometry (DESI-MS) imaging method to visually and quantitatively assess the distribution and metabolism of MACB in zebrafish. The results showed that MACB specifically accumulated in spinal cord particularly in female zebrafish. Meanwhile, the accumulation of MACB could pass through the blood-brain barrier (BBB) and induced microglial phagocytosis of neurons. Therefore, the intervention strategies should be explored to restrict the release of such substances, eliminating the potential risks for both human beings and the eco-environment.

Standpoints in mitochondrial dysfunction: Underlying mechanisms in search of therapeutic strategies

Mitochondrial dysfunction has been defined as a reduced efficiency of mitochondria to produce ATP given by a loss of mitochondrial membrane potential, alterations in the electron transport chain (ETC) function, with increase in reactive oxygen species (ROS) generation and decrease in oxygen consumption. During the last decades, mitochondrial dysfunction has been the focus of many researchers as a convergent point for the pathophysiology of several diseases. Numerous investigations have demonstrated that mitochondrial dysfunction is detrimental to cells, tissues and organisms, nevertheless, dysfunctional mitochondria can signal in a particular way in response to stress, a characteristic that may be useful to search for new therapeutic strategies with a common feature. The aim of this review addresses mitochondrial dysfunction and stress signaling as a promising target for future drug development.

Exercise Training Alleviates Cardiac Fibrosis through Increasing Fibroblast Growth Factor 21 and Regulating TGF-β1-Smad2/3-MMP2/9 Signaling in Mice with Myocardial Infarction

Exercise training has been reported to alleviate cardiac fibrosis and ameliorate heart dysfunction after myocardial infarction (MI), but the molecular mechanism is still not fully clarified. Fibroblast growth factor 21 (FGF21) exerts a protective effect on the infarcted heart. This study investigates whether exercise training could increase FGF21 protein expression and regulate the transforming growth factor-β1 (TGF-β1)-Smad2/3-MMP2/9 signaling pathway to alleviate cardiac fibrosis following MI. Male wild type (WT) C57BL/6J mice and Fgf21 knockout (Fgf21 KO) mice were used to establish the MI model and subjected to five weeks of different types of exercise training. Both aerobic exercise training (AET) and resistance exercise training (RET) significantly alleviated cardiac dysfunction and fibrosis, up-regulated FGF21 protein expression, inhibited the activation of TGF-β1-Smad2/3-MMP2/9 signaling pathway and collagen production, and meanwhile, enhanced antioxidant capacity and reduced cell apoptosis in the infarcted heart. In contrast, knockout of Fgf21 weakened the cardioprotective effects of AET after MI. In vitro, cardiac fibroblasts (CFs) were isolated from neonatal mice hearts and treated with H₂O₂ (100 μM, 6 h). Recombinant human FGF21 (rhFGF21, 100 ng/mL, 15 h) and/or 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR, 1 mM, 15 h) inhibited H₂O₂-induced activation of the TGF-β1-Smad2/3-MMP2/9 signaling pathway, promoted CFs apoptosis and reduced collagen production. In conclusion, exercise training increases FGF21 protein expression, inactivates the TGF-β1-Smad2/3-MMP2/9 signaling pathway, alleviates cardiac fibrosis, oxidative stress, and cell apoptosis, and finally improves cardiac function in mice with MI. FGF21 plays an important role in the anti-fibrosis effect of exercise training.

Upregulation of Small Ubiquitin-Like Modifier 2 and Protein SUMOylation as a Cardioprotective Mechanism Against Myocardial Ischemia-Reperfusion Injury

Background: Small ubiquitin-like modifier (SUMO) proteins modify proteins through SUMOylation as an essential protein post-translational modification (PTM) for regulating redox status, inflammation, and cardiac fibrosis in myocardial infarction. This study aimed to investigate whether natural product puerarin could alleviate myocardial ischemia/reperfusion injury (MI-RI) by targeting protein SUMOylation. Methods: Mouse MI-RI model was induced by ligating the left anterior descending (LAD) coronary artery and subsequently treated with puerarin at the dose of 100 mg/kg. Rat cardiomyocyte H9c2 cells were challenged by hypoxia/reoxygenation and treated with puerarin at concentrations of 10, 20, and 40 μM. The infarction area of mouse hearts was assessed by 2% TTC staining. Cell damage was analyzed for the release of lactate dehydrogenase (LDH) in serum and cell culture medium. Western blot technique was employed to detect the expression of SUMO2, phospho-ERK, pro-inflammatory biomarker COX2, fibrosis index galectin-3, apoptosis-related protein cleaved PARP-1. The activation of the estrogen receptor (ER) pathway was assayed by the dual-luciferase reporter system. Results: The present study validated that puerarin effectively reduced myocardial infarct size and LDH release in the mouse MI-RI model. In the cell culture system, puerarin effectively decreased the release of LDH and the protein level of COX2, galectin-3, and cleaved PARP-1. Mechanistic studies revealed that puerarin increased the expression of SUMO2, SUMOylation of proteins and the activation of ER/ERK pathway in cardiomyocytes. ER, ERK and SUMO2 inhibitors attenuated the cardioprotective effects of puerarin. Conclusion: Puerarin may alleviate myocardial injury by promoting protein SUMOylation through ER/ERK/SUMO2-dependent mechanism.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.

Hydrogen gas inhalation ameliorates cardiac remodelling and fibrosis by regulating NLRP3 inflammasome in myocardial infarction rats

It is noteworthy that prolonged cardiac structural changes and excessive fibrosis caused by myocardial infarction (MI) seriously interfere with the treatment of heart failure in clinical practice. Currently, there are no effective and practical means of either prevention or treatment. Thus, novel therapeutic approaches are critical for the long‐term quality of life of individuals with myocardial ischaemia. Herein, we aimed to explore the protective effect of H₂, a novel gas signal molecule with anti‐oxidative stress and anti‐inflammatory effects, on cardiac remodelling and fibrosis in MI rats, and to explore its possible mechanism. First, we successfully established MI model rats, which were then exposed to H₂ inhalation with 2% concentration for 28 days (3 hours/day). The results showed that hydrogen gas can significantly improve cardiac function and reduce the area of cardiac fibrosis. In vitro experiments further proved that H₂ can reduce the hypoxia‐induced damage to cardiomyocytes and alleviate angiotensin II‐induced migration and activation of cardiac fibroblasts. In conclusion, herein, we illustrated for the first time that inhalation of H₂ ameliorates myocardial infarction‐induced cardiac remodelling and fibrosis in MI rats and exert its protective effect mainly through inhibiting NLRP3‐mediated pyroptosis.

Didymin attenuates doxorubicin-induced cardiotoxicity by inhibiting oxidative stress

Objective

This study was designed to investigate the protective effects of didymin (Did) on doxorubicin (DOX)-induced cardiotoxicity.

Methods

After pretreatment with Did (2, 4, 8 mg/kg intraperitoneal i.p.) for 7 d, the male C57 mice were injected with single dose of DOX (20 mg/kg i.p.). The cardioprotective effect of Did was observed on the 7th day after DOX treatment.

Results

DOX delayed body growth and caused cardiac tissue injury, oxidative stress, and mitochondrial dysfunction. Similar experiments in H9C2 cardiomyocytes showed that DOX reduced cell viability, increased generation of reactive oxygen species (ROS) and fragmentation of DNA, decreased mitochondrial membrane potential, and induced cardiomyocyte apoptosis. However, all of these adverse effects were suppressed by Did pretreatment. Did increased protein expression of glutamate-L-cysteine ligase catalytic subunit (GCL), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). Besides, Did also induced activation of PI3K/AKT.

Conclusion

These findings indicated Did prevented DOX-induced cardiac injury and apoptosis via activating PI3K/AKT/Nrf2 signaling pathway.