Neutrophil-Mediated Cardiac Damage After Acute Myocardial Infarction: Significance of Defining a New Target Cell Type for Developing Cardioprotective Drugs

Multifaceted roles of neutrophils in cardiac disease

Neutrophils, the most abundant leukocytes in human blood, have long been recognized as critical first responders in the innate immune system's defense against pathogens. Some of the more notable innate antimicrobial properties of neutrophils include generation of superoxide free radicals like myeloperoxidase, production of proteases that reshape the extracellular matrix allowing for easier access to infected tissues, and release of neutrophil extracellular traps, extruded pieces of DNA that ensnare bacterial and fungi. These mechanisms developed to provide neutrophils with a vast array of specialized functions to provide the host defense against infection in an acute setting. However, emerging evidence over the past few decades has revealed a far more complex and nuanced role for these neutrophil-driven processes in various chronic conditions, particularly in cardiovascular diseases. The pathophysiology of cardiac diseases involves a complex interplay of hemodynamic, neurohumoral, and inflammatory factors. Neutrophils, as key mediators of inflammation, contribute significantly to this intricate network. Their involvement extends far beyond their classical role in pathogen clearance, encompassing diverse functions that can both exacerbate tissue damage and contribute to repair processes. Here, we consider the contributions of neutrophils to myocardial infarction, heart failure, cardiac arrhythmias, and nonischemic cardiomyopathies. Understanding these complex interactions is crucial for developing novel therapeutic strategies aimed at modulating neutrophil functions in these highly morbid cardiac diseases.

Association Between Systemic Immune-Inflammation Index and Outcomes of Acute Myocardial Infarction: A Systemic Review and Meta-Analysis

Objective: To assess the link between systemic immune-inflammation index (SII) and risk of major adverse cardiovascular events (MACE), contrast-induced nephropathy (CIN), and overall mortality in patients with acute myocardial infarction (AMI). Patients and Methods: Electronic search of PubMed, EMBASE, Web of Science, and Scopus databases was done for observational studies with the data on the association of SII and outcomes, such as MACE, and CIN in adult (≥18 y) patients with AMI. A random-effects model was used, and the pooled effect sizes were expressed as relative risk (RR) with corresponding 95% confidence intervals (CI). Subgroup analysis was conducted on the basis of the type of AMI (ST elevation myocardial infarction and non-ST elevation myocardial infarction), sample size (≥500 and <500), and study design. GRADE assessment was used to evaluate the certainty of the evidence. Results: The analysis included 23 studies. Most studies were conducted in China (n = 13), followed by Turkey (n = 10). Majority of the studies (n = 20) had a retrospective cohort design. Patients with high SII had increased risk of MACE (RR 2.95, 95% CI: 1.25, 6.99; n = 5, I2 = 97.5%), overall mortality (RR 2.59, 95% CI: 1.64, 4.07; n = 6, I2 = 58.0%), and CIN (RR 4.58, 95% CI: 3.44, 6.10; n = 4, I2 = 0.0%), compared with patients with lower SII. Egger's test detected publication bias for MACE (p = 0.047) and overall mortality (p = 0.012) but not for CIN. These associations remained valid in subgroup analysis. Conclusion: Findings suggest that higher SII in patients with AMI is associated with increased risks of MACE, CIN, and overall mortality. This underscores SII's potential as a prognostic marker in AMI.

Identification of regulator gene and pathway in myocardial ischemia-reperfusion injury: a bioinformatics and biological validation study

BACKGROUND

Acute myocardial infarction (AMI) is the primary cause of cardiac mortality worldwide. However, myocardial ischemia-reperfusion injury (MIRI) following reperfusion therapy is common in AMI, causing myocardial damage and affecting the patient's prognosis. Presently, there are no effective treatments available for MIRI.

METHODS

We performed a comprehensive bioinformatics analysis using three GEO datasets on differentially expressed genes, including gene ontology (GO), pathway enrichment analyses, and protein-protein interaction (PPI) network analysis. Cytoscape and LASSO methods were employed to identify novel regulator genes for ischemia-reperfusion (I/R). Notably, gene S100A9 was identified as a potential regulator of I/R. Additionally, clinical sample datasets were analyzed to prove the expression and mechanism of S100A9 and its down genes in I/R. The correlation of S100A9 with cardiac events was also examined to enhance the reliability of our results.

RESULTS

We identified 135 differential genes between the peripheral blood of 47 controls and 92 I/R patients. S100A9 was distinguished as a novel regulator gene of I/R with diagnostic potential. RT-qPCR test demonstrated significant upregulation of S100A9 in I/R. We also verified that S100A9 expression strongly correlates with left ventricular ejection fraction (LVEF) and MIRI.

CONCLUSION

This study confirms that S100A9 is a key regulator of I/R progression and may participate in ischemia-reperfusion injury by upregulating RAGE /NFKB-NLRP3 activation. Elevated S100A9 levels may serve as a marker for identifying high-risk MIRI patients, especially those with coronary artery no-reflow (CNR), who might benefit from targeted therapeutic interventions. Furthermore, Peripheral blood S100A9 in AMI represents a new therapeutic target for preventing MIRI.

Prognostic implications of system inflammation response index in atrial fibrillation patients with type 2 diabetes mellitus

Systemic inflammation plays a crucial role in the pathogenesis and prognosis of diabetes and cardiovascular diseases. System inflammation response index (SIRI), is an emerging biomarker designed to assess the extent of systemic inflammation. We aimed to delineate the prognostic significance of SIRI in patients with both AF and type 2 diabetes mellitus (T2DM). Utilizing the Medical Information Mart for Intensive Care IV (MIMIC-IV) (v2.2) repository, subjects divided into three groups based on the SIRI index. The primary endpoint of our study was all-cause mortality during hospitalization, with one-year mortality serving as the secondary endpoint. A cohort of 2054 AF and T2DM patients participated. COX regression analysis revealed elevated SIRI levels as an independent risk factor for both in-hospital and 1-year mortality. 192 patients died during hospitalization, and 265 died during the follow-up of 1 year. When treating the SIRI as a continuous variable, a higher SIRI was significantly associated with increased all-cause mortality both in-hospital [hazard ratio (HR) 1.015, 95%CI 1.010-1.020, P = 0.015] and 1-year (HR 1. 016, 95%CI 1.008-1.015, P = 0.012). Additionally, compared to patients with the lowest tertiles of SIRI, those with the highest tertiles of SIRI possessed significantly higher all-cause mortality both in-hospital and 1-year after multivariable adjustment, and this relationship remained pronounced in AF and T2DM patients [in-hospital mortality (HR: 1.863, 95% CI 1.189-2.918, P = 0.007); one-year mortality (HR: 2.143, 95% CI 1.621-2.831, P < 0.001)]. Our RCS analyses indicated a pronounced linear association between SIRI and mortality in T2DM (p-value for non-linear < 0.001). In AF patients with T2DM, high SIRI is an independent predictor of poor survival and may be helpful for patient's risk stratification.

Role of NLRP3 Inflammasome in Heart Failure Patients Undergoing Cardiac Surgery as a Potential Determinant of Postoperative Atrial Fibrillation and Remodeling: Is SGLT2 Cotransporter Inhibition an Alternative for Cardioprotection?

In heart failure (HF) patients undergoing cardiac surgery, an increased activity of mechanisms related to cardiac remodeling may determine a higher risk of postoperative atrial fibrillation (POAF). Given that atrial fibrillation (AF) has a negative impact on the course and management of HF, including the need for anticoagulation therapy, identifying the factors associated with AF occurrence after cardiac surgery is crucial for the prognosis of these patients. POAF is thought to occur when various clinical and biochemical triggers act on susceptible cardiac tissue (first hit), with oxidative stress and inflammation during cardiopulmonary bypass (CPB) surgery being potential contributing factors (second hit). However, the molecular mechanisms involved in these processes remain poorly characterized. Recent research has shown that patients who later develop POAF often have pre-existing abnormalities in calcium handling and activation of NLRP3-inflammasome signaling in their atrial cardiomyocytes. These molecular changes may make cardiomyocytes more susceptible to spontaneous Ca2+-releases and subsequent arrhythmias, particularly when exposed to inflammatory mediators. Additionally, some clinical studies have linked POAF with elevated preoperative inflammatory markers, but there is a need for further research in order to better understand the impact of CPB surgery on local and systemic inflammation. This knowledge would make it possible to determine whether patients susceptible to POAF have pre-existing inflammatory conditions or cellular electrophysiological factors that make them more prone to developing AF and cardiac remodeling. In this context, the NLRP3 inflammasome, expressed in cardiomyocytes and cardiac fibroblasts, has been identified as playing a key role in the development of HF and AF, making patients with pre-existing HF with reduced ejection fraction (HFrEF) the focus of several clinical studies with interventions that act at this level. On the other hand, HFpEF has been linked to metabolic and non-ischemic risk factors, but more research is needed to better characterize the myocardial remodeling events associated with HFpEF. Therefore, since ventricular remodeling may differ between HFrEF and HFpEF, it is necessary to perform studies in both groups of patients due to their pathophysiological variations. Clinical evidence has shown that pharmacological therapies that are effective for HFrEF may not provide the same anti-remodeling benefits in HFpEF patients, particularly compared to traditional adrenergic and renin-angiotensin-aldosterone system inhibitors. On the other hand, there is growing interest in medications with pleiotropic or antioxidant/anti-inflammatory effects, such as sodium-glucose cotransporter 2 inhibitors (SGLT-2is). These drugs may offer anti-remodeling effects in both HFrEF and HFpEF by inhibiting pro-inflammatory, pro-oxidant, and NLRP3 signaling pathways and their mediators. The anti-inflammatory, antioxidant, and anti-remodeling effects of SGLT-2 i have progressively expanded from HFrEF and HFpEF to other forms of cardiac remodeling. However, these advances in research have not yet encompassed POAF despite its associations with inflammation, oxidative stress, and remodeling. Currently, the direct or indirect effects of NLRP3-dependent pathway inhibition on the occurrence of POAF have not been clinically assessed. However, given that NLRP3 pathway inhibition may also indirectly affect other pathways, such as inhibition of NF-kappaB or inhibition of matrix synthesis, which are strongly linked to POAF and cardiac remodeling, it is reasonable to hypothesize that this type of intervention could play a role in preventing these events.

Myeloperoxidase as a Promising Therapeutic Target after Myocardial Infarction

Coronary artery disease (CAD) and myocardial infarction (MI) remain leading causes of death and disability worldwide. CAD begins with the formation of atherosclerotic plaques within the intimal layer of the coronary arteries, a process driven by persistent arterial inflammation and oxidation. Myeloperoxidase (MPO), a mammalian haem peroxidase enzyme primarily expressed within neutrophils and monocytes, has been increasingly recognised as a key pro-inflammatory and oxidative enzyme promoting the development of vulnerable coronary atherosclerotic plaques that are prone to rupture, and can precipitate a MI. Mounting evidence also implicates a pathogenic role for MPO in the inflammatory process that follows a MI, which is characterised by the rapid infiltration of activated neutrophils into the damaged myocardium and the release of MPO. Excessive and persistent cardiac inflammation impairs normal cardiac healing post-MI, resulting in adverse cardiac outcomes and poorer long-term cardiac function, and eventually heart failure. This review summarises the evidence for MPO as a significant oxidative enzyme contributing to the inappropriate inflammatory responses driving the progression of CAD and poor cardiac healing after a MI. It also details the proposed mechanisms underlying MPO's pathogenic actions and explores MPO as a novel therapeutic target for the treatment of unstable CAD and cardiac damage post-MI.

Predictive value of triglyceride glucose index combined with neutrophil-to-lymphocyte ratio for major adverse cardiac events after PCI for acute ST-segment elevation myocardial infarction

Acute ST-segment elevation myocardial infarction (STEMI) is a severe cardiovascular disease that poses a significant threat to the life and health of patients. This study aimed to investigate the predictive value of triglyceride glucose index (TyG) combined with neutrophil-to-lymphocyte ratio (NLR) for in-hospital cardiac adverse event (MACE) after PCI in STEMI patients. From October 2019 to June 2023, 398 STEMI patients underwent emergency PCI in the Second People's Hospital of Hefei. Stepwise regression backward method and multivariate logistic regression analysis were used to screen the independent risk factors of MACE in STEMI patients. To construct the prediction model of in-hospital MACE after PCI in STEMI patients: Grace score model is the old model (model A); TyG combined with NLR model (model B); Grace score combined with TyG and NLR model is the new model (model C). We assessed the clinical usefulness of the predictive model by comparing Integrated Discrimination Improvement (IDI), Net Reclassification Index (NRI), Receiver Operating Characteristic Curve (ROC), and Decision Curve Analysis (DCA). Stepwise regression and multivariate logistic regression analysis showed that TyG and NLR were independent risk factors for in-hospital MACE after PCI in STEMI patients. The constructed Model C was compared to Model A. Results showed NRI 0.5973; NRI + 0.3036, NRI - 0.2937, IDI 0.3583. These results show that the newly developed model C predicts the results better than model A, indicating that the model is more accurate. The ROC analysis results showed that the AUC of Model A for predicting MACE in STEMI was 0.749. Model B predicted MACE in STEMI with an AUC of 0.685. Model C predicted MACE in STEMI with an AUC of 0.839. For DCA, Model C has a better net return between threshold probability 0.1 and 0.78, which is better than Model A and Model B. In this study, by combining TyG, NLR, and Grace score, it was shown that TyG combined with NLR could reasonably predict the occurrence of MACE after PCI in STEMI patients and the clinical utility of the prediction model.

Identification of molecular markers for predicting the severity of heart failure after AMI: An Olink precision proteomic study

BACKGROUND

Acute myocardial infarction (AMI) still has a high incidence of varying degrees of heart failure (HF). The aim of this study is to identify new molecular markers for predicting the severity of HF after AMI.

METHODS

We analyzed demographic indicators, past medical history, clinical indicators, major adverse cardiac events (MACEs) and molecular markers in patients with different Killip classifications after AMI. Olink proteomics was used to explore new molecular markers for predicting different severity of HF after AMI.

RESULTS

Neutrophil count was the independent risk factors for in-hospital MACEs. Nineteen differentially expressed proteins (DEPs) increased significantly with increasing Killip classification. Five DEPs were also found to have an AUC (95 % CI) value greater than 0.8: GDF-15, NT-pro BNP, TNF-R2, TNF-R1 and TFF3.

CONCLUSIONS

Neutrophil count, GDF-15, TNF-R2, TNF-R1 and TFF3 were closely related to the Killip classification of HF after AMI, which suggests that the inflammatory response plays an important role in the severity of HF after AMI and that regulating inflammation might become a new target for controlling HF.

High neutrophil-to-lymphocyte ratio is associated with cancer therapy-related cardiovascular toxicity in high-risk cancer patients under immune checkpoint inhibitor therapy

BACKGROUND

Cancer therapy-related cardiovascular toxicity (CTR-CVT) from immune checkpoint inhibitor (ICI) therapy is still incompletely characterized, and patients with pre-existing cardiovascular disease represent a particularly high-risk cohort. Valid parameters for risk stratification of these patients are missing. Neutrophil-to-lymphocyte ratio (NLR) has been shown to predict mortality and adverse events in other cardiovascular cohorts. The present study aims to examine the predictive capacity of NLR for risk stratification of patients particularly vulnerable for CTR-CVT under ICI therapy.

METHODS

We performed an analysis of 88 cancer patients (69 ± 11 years, 25% female) with pre-existing cardiovascular disease under ICI therapy from the prospective Essen Cardio-Oncology Registry (ECoR). NLR was assessed at patient enrollment and the population was divided through receiver operator characteristic (ROC) curve analysis in patients with low (< 4.57) and high (≥ 4.57) NLR. Endpoint was the whole spectrum of CTR-CVT, according to the European guidelines on cardio-oncology. The median follow-up was 357 days (interquartile range (IQR): 150-509 days).

RESULTS

We observed 4 cases of myocarditis, 17 cases of vascular toxicity, 3 cases of arterial hypertension, 22 cases of arrhythmia or QTc prolongation and 17 cases of cardiovascular dysfunction. NLR was associated with overall CTR-CVT by univariable Cox regression (hazard ratio (HR): 1.443; 95% confidence interval (CI) 1.082-1.925; p = 0.013). However, this association was attenuated after adjusting for further confounders.

CONCLUSION

NLR is moderately associated with CTR-CVT in cancer patients with pre-existing cardiovascular disease under ICI therapy. Surveillance of NLR during ICI therapy might be an effective and economically biomarker for risk stratification in these high-risk patients.

Astragalus (Astragalus mongholicus) Improves Ventricular Remodeling via ESR1 Downregulation RhoA/ROCK Pathway

Astragalus (Astragalus mongholicus) alleviates myocardial remodeling caused by hypertension. However, the detailed molecular mechanism is unclear. This study aims to investigate the effect of Astragalus on ventricular remodeling in ovariectomized spontaneous hypertensive rats (OVX-SHR).Female SHR/NCrl rats were subjected to bilateral ovariectomy to establish the OVX-SHR model and treated with Astragalus extract by gavage. The hemodynamics and cardiac function parameters were measured. HE and Masson staining were used to detect the pathological structure of myocardial remodeling and observe the hyperplasia of myocardial collagen fibers. The immunohistochemistry tested the level of α-SMA. The expression levels of inflammatory cytokines, IκB, p65, Cleaved-Caspase3, RhoA, and ROCK1/2 were detected using Western blot. The method of qRT-PCR measured the expression of matrix metalloproteinase (MMP-2 and MMP-9).Hemodynamic and cardiac function parameters were significantly improved after a high dose of Astragalus extract and Valsartan treatment. The myocardial integrity of the model group was significantly reduced, arranged loosely, and disordered, while the expression of α-SMA was increased. However, Astragalus extract and Valsartan treatments significantly reduced the pathological damage and α-SMA. The levels of TNF-α, IL-1β, IL-6, TGF-β, MMP-2, and MMP-9 in the model group were increased but decreased after Astragalus extract treatment. Adding an ESR1 inhibitor attenuated the improvement effect of Astragalus extract on myocardial remodeling and restored the expression of RhoA and ROCK1/2.Astragalus extract attenuates the cardiac damage in OVX-SHR by downregulating the RhoA/ROCK pathway through ESR1.

Application of locally responsive design of biomaterials based on microenvironmental changes in myocardial infarction

Morbidity and mortality caused by acute myocardial infarction (AMI) are on the rise, posing a grave threat to the health of the general population. Up to now, interventional, surgical, and pharmaceutical therapies have been the main treatment methods for AMI. Effective and timely reperfusion therapy decreases mortality, but it cannot stimulate myocardial cell regeneration or reverse ventricular remodeling. Cell therapy, gene therapy, immunotherapy, anti-inflammatory therapy, and several other techniques are utilized by researchers to improve patients' prognosis. In recent years, biomaterials for AMI therapy have become a hot spot in medical care. Biomaterials furnish a microenvironment conducive to cell growth and deliver therapeutic factors that stimulate cell regeneration and differentiation. Biomaterials adapt to the complex microenvironment and respond to changes in local physical and biochemical conditions. Therefore, environmental factors and material properties must be taken into account when designing biomaterials for the treatment of AMI. This article will review the factors that need to be fully considered in the design of biological materials.

Decreased thioredoxin reductase 3 expression promotes nickel-induced damage to cardiac tissue via activating oxidative stress-induced apoptosis and inflammation

Thioredoxin reductase 3 (Txnrd3) plays a crucial role in antioxidant and anti-cancer activities, and sperm maturation. The damage of heavy metals, including Nickel (Ni), is the most prominent harm in social development, and hampering Txnrd3 might exacerbate Ni-induced cardiac damage. In this study, a total of 160 8-week-old C57BL/N male mice with 25-30 g weight of Txnrd3+/+ wild-type and Txnrd3-/- homozygote-type were randomly divided into eight groups. The mice in the control and Ni groups were gavaged with distilled water and a freshly prepared 10 mg/kg NiCl₂ solution. Melatonin (Mel) groups were administered at a concentration of 2 mg/kg for 21 days at the mice's 0.1 ml/10 g body weight. Ni exposure up-regulated the messenger RNA (mRNA) levels of mitochondrial apoptosis (caspase-3, caspase-9, cytochrome c, p53, and BAX), autophagy (LC3, ATG 1, ATG 7, and Beclin-1), and inflammation (TNF-α, COX 2, IL-1β, IL-2, IL-6, and IL-7)-related markers, but down-regulated the mRNA levels of BCL-2, p62 and mTOR (p < .05). Ni exposure decreased the expression of BCL-2 and p62 protein but increased the expression levels of caspase-3, caspase-9, cytochrome c, p53, BAX, ATG 7, Beclin-1, TNF-α, COX 2, IL-1β and IL-2 protein (p < .05). Ni increased the contents of glutathione disulfide (GSSG) and malondialdehyde (MDA) and decreased the activities of catalase (CAT) and total superoxide dismutase (T-SOD) (p < .05). Decreased Txnrd3 expression significantly exacerbated changes compared to the Ni exposure (p < .05). Mel significantly attenuated these changes, but the effect decreased when Txnrd3 was inhibited (p < .05). In conclusion, decreased Txnrd3 expression promoted Ni-induced mitochondrial apoptosis and inflammation via oxidative stress and aggravated heart damage in mice. Decreased Txnrd3 expression significantly reduced the protective effect of Mel to Ni exposure.

Association of Neutrophil to High-Density Lipoprotein Cholesterol Ratio with Cardiac Ultrasound Parameters and Cardiovascular Risk: A Cross-Sectional Study Based on Healthy Populations

Background

Neutrophils and high-density lipoprotein cholesterol (HDL-C) are significantly linked to cardiovascular disease (CVD). This study investigates the correlation of neutrophil count to HDL-C ratio (NHR) with cardiac ultrasound parameters and cardiovascular risk in healthy populations.

Materials and Methods

Firstly, NHR was calculated based on neutrophils and HDL-C. Then, the differences in basic clinical characteristics and cardiac ultrasound parameters were compared between the high and low NHR groups, males and females. Subsequently, cardiovascular risk was predicted according to the Chinese 10-year ischemic cardiovascular disease (ICVD) risk assessment tool for people aged 35-60 years. Finally, the correlation between NHR and cardiac ultrasound parameters and cardiovascular risk was calculated.

Results

A total of 3020 healthy participants, 1879 males and 1141 females, were included. Participants in the high NHR group had significantly increased Aorta (AO), Left Atrium (LA), Right Atrium (RA), Right Ventricle (RV), End Systolic Diameter of Left Ventricle (ESD), End Diastolic Diameter of Left Ventricle (EDD), Main Pulmonary Artery (MPA), Right Ventricular Outflow Tract (RVOT), Interventricular Septum (IVS), Left Ventricular Posterior Wall (LVPW), and cardiovascular risk and decreased E/A values compared to those in the low NHR group. The same results were found in males participants compared to females. A total of 1670 participants underwent ICVD risk assessment tool. Cardiovascular risk was significantly higher in those with high NHR and in males than in those with low NHR and in females. Correlation analysis showed that NHR was positively correlated with AO, LA, RA, RV, ESD, EDD, MPA, RVOT, IVS, LVPW and cardiovascular risk, and negatively correlated with E/A values.

Conclusion

Our study demonstrates that NHR is significantly associated with cardiac ultrasound parameters and cardiovascular risk in healthy populations. NHR may serve as a useful indicator for the early diagnosis and treatment of cardiovascular disease among healthy populations.

Protective Effect of Ginsenosides Rg1 on Ischemic Injury of Cardiomyocytes After Acute Myocardial Infarction

Acute myocardial infarction (AMI) leads to anoxia and ischemia of cardiomyocytes, followed by apoptosis. This study investigated the protective effect of ginsenoside Rg1 (Rg1) on myocardial ischemia injury in rats with AMI. Rats were randomly divided into five groups: group A (blank control group), group B (hypoxia/reoxygenation group), group C (hypoxia/reoxygenation + 10 mg/L Rg1), group D (hypoxia/reoxygenation + 20 mg/L Rg1) and group E (hypoxia/reoxygenation + 40 mg/L Rg1). The survival rate, apoptosis rate, expression of cyclin-dependent kinase 4 (CDK4), fibroblast growth factor 9 (FGF9), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), microvessel density and myocardial infarction area of rats in each group were compared. The expressions of CDK4 and FGF9, the contents of SOD and GSH-Px in groups C, D and E injected with Rg1 were significantly promoted compared to group B without Rg1 injection (P < 0.05). The survival rate of myocardial cells was significantly increased while the apoptosis rate was significantly decreased in group C, D, E compared to group B (P < 0.05). On the 3rd, 7th and 10th day following Rg1 treatment, the infarct area of E group was significantly decreased in three groups C, D, E, and the microvessel density of infarct area was significantly increased compared with group B (P < 0.05). So, Rg1 can improve the survival rate of myocardial cells, reduce the apoptosis rate and the area of myocardial infarction, and increase the microvessel density of infarct area, thus playing a protective role in ischemic myocardial cells of AMI rats.

Interleukin-6 inhibition in ST-elevation myocardial infarction: Immune cell profile in the randomised ASSAIL-MI trial

Background

We recently showed that interleukin (IL)-6 inhibition by tocilizumab improves myocardial salvage in ST-elevation myocardial infarction (STEMI). However, the mechanisms for this effect are not clear.

Methods

In this exploratory sub-study of the ASSAIL-MI trial, we examined leukocyte differential counts and their relation to myocardial salvage and peak troponin T (TnT) in STEMI patients randomised to tocilizumab (n = 101) or placebo (n = 98). We performed RNA-sequencing on whole blood (n = 40) and T cells (n = 20). B and T cell subpopulations were examined by flow cytometry (n = 69).

Findings

(i) STEMI patients had higher neutrophil counts at hospitalisation compared with stable angina patients. (ii) After percutaneous coronary intervention there was a gradual decline in neutrophils, which was significantly more pronounced in the tocilizumab group. (iii) The decrease in neutrophils in the tocilizumab group was associated with improved myocardial salvage and lower peak TnT. (iv) RNA-sequencing suggested that neutrophil function was also attenuated by tocilizumab. (v) B and T cell sub-populations changed only minimally after STEMI with minor effects of tocilizumab, supported as well by RNA-sequencing analyses of T cells. (vi) However, a low CD8⁺ count was associated with improved myocardial salvage in patients admitted to the hospital > 3 h after symptom onset.

Interpretation

Tocilizumab induced a rapid reduction in neutrophils and seemed to attenuate neutrophil function in STEMI patients potentially related to the beneficial effects of tocilizumab on myocardial salvage.

Funding

South-Eastern Norway Regional Health Authority (Nos. 2019067, 2017084), the Central Norway Regional Health Authority and Norwegian Research Council (No. 283867).

The Admission (Neutrophil+Monocyte)/Lymphocyte Ratio Is an Independent Predictor for In-Hospital Mortality in Patients With Acute Myocardial Infarction

Purpose

Peripheral differential leukocyte counts are accepted prognostic indicators in patients with acute myocardial infarction (AMI). Herein, we assessed the value of the admission (neutrophil+monocyte)/lymphocyte ratio (NMLR) in predicting in-hospital mortality in these patients.

Materials and Methods

Samples of patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database meeting the criteria were included. Receiver operating characteristic (ROC) curves were plotted to explore the predictive value and the optimum cut-off value of admission NMLR. Univariate and multivariate Cox regression analyses and restricted cubic spline (RCS) were performed to determine and visualize the association between admission NMLR and in-hospital mortality. The Kaplan-Meier (KM) method was used to plot survival curves of two groups with different admission NMLR levels.

Results

Samples in the non-survival group had higher admission NMLR values than samples in the survival group (12.11 [7.22–21.05] vs. 6.38 [3.96–11.25], P &lt; 0.05). The area under the ROC curve (AUROC) [0.707 (95% Confidence Interval, 0.677–0.737)] was significantly better than those of other indicators related to peripheral differential leukocyte counts, and the optimal cut-off value was 8.518. Cox regression analysis identified that higher admission NMLR was an independent risk factor for in-hospital mortality. RCS visualized the uptrend and the non-linear relationship between admission NMLR and in-hospital mortality (P-value for non-linearity &lt;0.05). The KM survival curve of the high admission NMLR group was significantly lower than that of the low admission NMLR group (P &lt; 0.001), and the former was associated with an increased risk of in-hospital mortality compared to the latter (Hazard Ratio, 1.452; 95% Confidence Interval, 1.132–1.862; P &lt; 0.05).

Conclusion

An elevated admission NMLR is an independent predictor for high in-hospital mortality in patients with AMI. And it is superior to other leukocyte-related indexes.

Design, synthesis and biological evaluation of novel nitric oxide donors with antioxidative activity

Reactive oxygen species (ROS) are the primary cause of organic nitrate drug tolerance and endothelial dysfunction. In order to scavenge the ROS and maintain the therapeutic effect of nitrates, we designed and synthesized ten new types of dual-acting nitrate molecules by combining NIT-type nitroxides and 5-ISMN. These included two types of novel epimeric nitroxide-nitrate conjugates (15(S) and 15(R)), which had pharmacophore connections. We also synthesized 8 NIT radicals without 5-ISMN in order to compare the activities of these novel nitric oxide donors. Several dual-acting nitroxide-based nitrate conjugates showed the ability to release NO and cause anti-oxidant effects in human umbilical vein endothelial cells. Among these conjugates, 15(S) showed the most prominent pro-vasodilative effect. In angiotensin II infusion-induced hypertensive mice, 15(S) treatment for 4 weeks decreased both the systolic and diastolic blood pressures and ameliorated the vascular endothelial and smooth muscle functions of isolated thoracic aortas. In addition, the vascular structure of the mice was restored and their vascular oxidative stress was decreased. The results suggest that these novel nitric oxide donors can be used as potential drugs in the treatment of vascular diseases. Therefore, the strategy of using a combination of antioxidants and NO-donors can be a promising way to develop novel organic nitrate drugs for future use in combating disease.

Hypochlorite-Modified LDL Induces Arrhythmia and Contractile Dysfunction in Cardiomyocytes

Neutrophil-derived myeloperoxidase (MPO) and its potent oxidant, hypochlorous acid (HOCl), gained attention as important oxidative mediators in cardiac damage and dysfunction. As cardiomyocytes generate low-density lipoprotein (LDL)-like particles, we aimed to identify the footprints of proatherogenic HOCl-LDL, which adversely affects cellular signalling cascades in various cell types, in the human infarcted myocardium. We performed immunohistochemistry for MPO and HOCl-LDL in human myocardial tissue, investigated the impact of HOCl-LDL on electrophysiology and contractility in primary cardiomyocytes, and explored underlying mechanisms in HL-1 cardiomyocytes and human atrial appendages using immunoblot analysis, qPCR, and silencing experiments. HOCl-LDL reduced ICa,L and IK1, and increased INaL, leading to altered action potential characteristics and arrhythmic events including early- and delayed-afterdepolarizations. HOCl-LDL altered the expression and function of CaV1.2, RyR2, NCX1, and SERCA2a, resulting in impaired contractility and Ca2+ homeostasis. Elevated superoxide anion levels and oxidation of CaMKII were mediated via LOX-1 signaling in HL-1 cardiomyocytes. Furthermore, HOCl-LDL-mediated alterations of cardiac contractility and electrophysiology, including arrhythmic events, were ameliorated by the CaMKII inhibitor KN93 and the INaL blocker, ranolazine. This study provides an explanatory framework for the detrimental effects of HOCl-LDL compared to native LDL and cardiac remodeling in patients with high MPO levels during the progression of cardiovascular disease.

The Predictive role of Neutrophil-to-Lymphocyte Ratio (NLR) and Mean Platelet Volume-to-Lymphocyte Ratio (MPVLR) for Cardiovascular Events in Adult Patients with Acute Heart Failure

Introduction

The inflammatory response plays a potential role for the pathogenesis and adverse outcomes of heart failure (HF). We aimed to explore the predictive role of baseline neutrophil-to-lymphocyte ratio (NLR) and mean platelet volume-to-lymphocyte ratio (MPVLR) on cardiovascular events (CVEs) in patients hospitalized with acute HF.

Materials and Methods

A retrospective cohort study was conducted in 321 patients with HF between January 2017 and December 2019. The association between their NLR, MPVLR, and combined NLR and MPVLR and CVEs, rehospitalization for HF, in-hospital death, and a composite outcome was explored by survival analysis using a Cox proportional hazard model. They were separately investigated and compared with the area under the receiver operating characteristics curve (AUC).

Results

Up to the end of the 3-year follow-up, 96 (29.9%) had CVEs, 106 (33.0%) died, 62 (19.3%) were rehospitalized with HF, and 21 (6.5%) died during admission. The NLR and MPVLR were significantly associated with CVEs (adjusted HR for NLR ≥ 3.29, 3.11; 95% CI, 1.98-4.89; MPVLR ≥ 8.57, 2.86; 95% CI, 1.87-4.39), readmissions for HF (adjusted HR for NLR ≥ 3.58, 2.70; 95% CI, 1.58-4.61; MPVLR ≥ 6.43, 2.84; 95% CI,1.59-5.07), in-hospital mortality (adjusted HR for NLR ≥ 3.29, 9.54; 95% CI, 2.19-41.40; MPVLR ≥ 8.57, 7.87; 95% CI, 2.56-24.19), and composite outcome (adjusted HR for NLR ≥ 3.32, 4.76; 95% CI, 3.29-6.89; MPVLR ≥ 7.07, 3.64; 95% CI, 2.58-5.15). The AUC of NLR and MPVLR for CVEs were 0.67 (95% CI, 0.61-0.72) and 0.63 (95% CI, 0.58-0.69). Combined NLR and MPVLR increased the AUC to 0.77 (95% CI, 0.72-0.83) with statistical significance.

Conclusion

The elevated NLR and MPVLR on admission in patients with acute HF were independently associated with worse CVEs, rehospitalization for HF, in-hospital death, and composite outcomes. These economical biomarkers should be considered in the management and follow-up care of patients with acute HF.

Oral pre-treatment with thiocyanate (SCN-) protects against myocardial ischaemia-reperfusion injury in rats

Despite improvements in revascularization after a myocardial infarction, coronary disease remains a major contributor to global mortality. Neutrophil infiltration and activation contributes to tissue damage, via the release of myeloperoxidase (MPO) and formation of the damaging oxidant hypochlorous acid. We hypothesized that elevation of thiocyanate ions (SCN⁻), a competitive MPO substrate, would modulate tissue damage. Oral dosing of rats with SCN⁻, before acute ischemia–reperfusion injury (30 min occlusion, 24 h or 4 week recovery), significantly reduced the infarct size as a percentage of the total reperfused area (54% versus 74%), and increased the salvageable area (46% versus 26%) as determined by MRI imaging. No difference was observed in fractional shortening, but supplementation resulted in both left-ventricle end diastolic and left-ventricle end systolic areas returning to control levels, as determined by echocardiography. Supplementation also decreased antibody recognition of HOCl-damaged myocardial proteins. SCN⁻ supplementation did not modulate serum markers of damage/inflammation (ANP, BNP, galectin-3, CRP), but returned metabolomic abnormalities (reductions in histidine, creatine and leucine by 0.83-, 0.84- and 0.89-fold, respectively), determined by NMR, to control levels. These data indicate that elevated levels of the MPO substrate SCN⁻, which can be readily modulated by dietary means, can protect against acute ischemia–reperfusion injury.

5-Methoxytryptophan attenuates postinfarct cardiac injury by controlling oxidative stress and immune activation

AIMS

Myocardial infarction (MI) remains a major cause of heart failure. 5-Methoxytryptophan (5-MTP), a 5-methoxyindole metabolite of L-tryptophan, exerts anti-inflammatory and antifibrotic effects, but MI impairs the biosynthesis of cardiac 5-MTP. Therefore, we evaluated the effect of exogenous 5-MTP administration on rescuing post-MI cardiac injury.

METHODS AND RESULTS

After a detailed pharmacokinetic analysis of 5-MTP, Sprague Dawley rats that had undergone left anterior descending coronary artery ligation received intraperitoneal administration of either 17 mg/kg 5-MTP or saline at 0.5 and 24 h after MI. Cardiac systolic function, infarction size, and fibrosis were evaluated using echocardiography, triphenyltetrazolium chloride staining, and Masson trichrome staining, respectively. Myocardial apoptosis was analyzed by staining for caspase-3 and cardiac troponin I. 5-MTP treatment decreased the infarct area and myocardial apoptosis; attenuated systolic dysfunction and left ventricular dilatation; and reduced cardiomyocyte hypertrophy, myocardial fibrosis, and infarct expansion. Crucially, 5-MTP alleviated oxidative stress by preserving mitochondrial antioxidant enzymes and downregulating reactive oxygen species-generating NADPH oxidase isoforms and endothelin-1. Consequently, 5-MTP-treated MI rat hearts exhibited lower levels of chemokines and cytokines, namely interleukin (IL)-1β, IL-18, IL-6, C-C motif chemokine ligand (CCL)-2, and CCL5, accompanied by reduced infiltration of CD11b⁺ cells and CD4⁺ T cells. Notably, 5-MTP protected against H₂O₂-induced damage in HL-1 cardiomyocytes and human umbilical vein endothelial cells in vitro.

CONCLUSION

5-MTP prevented post-MI cardiac injury by promoting mitochondrial stabilization and controlling redox imbalance. This cytoprotective effect ameliorated macrophage and T-cell infiltration, thus reducing the infarct size, attenuating fibrosis, and restoring myocardial function.

Transforming Growth Factor Beta (TGF-β1) Induces Pro-Reparative Phenotypic Changes in Epicardial Cells in Mice

We evaluated the content of active form of TGF-β1 in the intact and post-infarction heart and the effect of this factor on the properties of epicardial cells. During the acute stage after myocardial infarction, the production of TGF-β1 in the heart increased, which closely correlated with activation of epicardial cells (appearance of a pool of Wt1+ epicardial cells entering the epithelial-mesenchymal transition). The role of TGF-β1 as the factor of epicardial activation was confirmed by the results of in vitro experiments: addition of recombinant TGF-β1 to cultured epicardial cells led to enhanced expression of genes of epithelial-mesenchymal transition and phenotypic transformation of these cells leading to the appearance of cells with markers of smooth muscle cells and fibroblasts. Our findings suggest that the regulatory axis "TGF-β1-epicardium cells" can be considered as an important link of the post-infarction reparative process and adaptive response during heart remodeling after myocardial infarction and as the target for therapeutic interventions.

COVID-19 associated cardiac disease: Is there a role of neutrophil extracellular traps in pathogenesis?

<abstract> <p>The COVID-19 pandemic has driven an upheaval of new research, providing key insights into the pathogenesis of this disease. Lymphocytopenia, hyper-inflammation and cardiac involvement are prominent features of the disease and have prognostic value. However, the mechanistic links among these phenomena are not well understood. Likewise, some COVID-19 patients exhibit multi-organ failure with diseases affecting the cardiac system, appearing to be an emerging feature of the COVID-19 pandemic. Neutrophil extracellular traps (NETs) have been frequently correlated with larger infarct sizes and can predict major adverse cardiac events. However, the exact mechanism behind this remains unknown. Although the excessive NET formation can drive inflammation, particularly endothelial and promote thrombosis, it is essential to normal immunity. In this paper, we postulate the role of NETs in cardiac disease by providing an overview of the relationship between NET and inflammasome activities in lung and liver diseases, speculating a link between these entities in cardiac diseases as well. Future research is required to specify the role of NETs in COVID-19, since this carries potential therapeutic significance, as inhibition of NETosis could alleviate symptoms of this disease. Knowledge gained from this could serve to inform the assessment and therapeutics of other hyper inflammatory diseases affecting the heart and vasculature alike.</p> </abstract>

Oxidative Stress and Antioxidant Treatments in Cardiovascular Diseases

Oxidative stress plays a key role in many physiological and pathological conditions. The intracellular oxidative homeostasis is tightly regulated by the reactive oxygen species production and the intracellular defense mechanisms. Increased oxidative stress could alter lipid, DNA, and protein, resulting in cellular inflammation and programmed cell death. Evidences show that oxidative stress plays an important role in the progression of various cardiovascular diseases, such as atherosclerosis, heart failure, cardiac arrhythmia, and ischemia-reperfusion injury. There are a number of therapeutic options to treat oxidative stress-associated cardiovascular diseases. Well known antioxidants, such as nutritional supplements, as well as more novel antioxidants have been studied. In addition, novel therapeutic strategies using miRNA and nanomedicine are also being developed to treat various cardiovascular diseases. In this article, we provide a detailed description of oxidative stress. Then, we will introduce the relationship between oxidative stress and several cardiovascular diseases. Finally, we will focus on the clinical implications of oxidative stress in cardiovascular diseases.

Myeloperoxidase-Derived 2-Chlorohexadecanal Is Generated in Mouse Heart during Endotoxemia and Induces Modification of Distinct Cardiomyocyte Protein Subsets In Vitro

Sepsis is a major cause of mortality in critically ill patients and associated with cardiac dysfunction, a complication linked to immunological and metabolic aberrations. Cardiac neutrophil infiltration and subsequent release of myeloperoxidase (MPO) leads to the formation of the oxidant hypochlorous acid (HOCl) that is able to chemically modify plasmalogens (ether-phospholipids) abundantly present in the heart. This reaction gives rise to the formation of reactive lipid species including aldehydes and chlorinated fatty acids. During the present study, we tested whether endotoxemia increases MPO-dependent lipid oxidation/modification in the mouse heart. In hearts of lipopolysaccharide-injected mice, we observed significantly higher infiltration of MPO-positive cells, increased fatty acid content, and formation of 2-chlorohexadecanal (2-ClHDA), an MPO-derived plasmalogen modification product. Using murine HL-1 cardiomyocytes as in vitro model, we show that exogenously added HOCl attacks the cellular plasmalogen pool and gives rise to the formation of 2-ClHDA. Addition of 2-ClHDA to HL-1 cardiomyocytes resulted in conversion to 2-chlorohexadecanoic acid and 2-chlorohexadecanol, indicating fatty aldehyde dehydrogenase-mediated redox metabolism. However, a recovery of only 40% indicated the formation of non-extractable (protein) adducts. To identify protein targets, we used a clickable alkynyl analog, 2-chlorohexadec-15-yn-1-al (2-ClHDyA). After Huisgen 1,3-dipolar cycloaddition of 5-tetramethylrhodamine azide (N₃-TAMRA) and two dimensional-gel electrophoresis (2D-GE), we were able to identify 51 proteins that form adducts with 2-ClHDyA. Gene ontology enrichment analyses revealed an overrepresentation of heat shock and chaperone, energy metabolism, and cytoskeletal proteins as major targets. Our observations in a murine endotoxemia model demonstrate formation of HOCl-modified lipids in the heart, while pathway analysis in vitro revealed that the chlorinated aldehyde targets specific protein subsets, which are central to cardiac function.