Matrix Metalloproteinases in Myocardial Infarction and Heart Failure

The Elevated Inflammatory Status of Neutrophils Is Related to In-Hospital Complications in Patients with Acute Coronary Syndrome and Has Important Prognosis Value for Diabetic Patients

Despite neutrophil involvement in inflammation and tissue repair, little is understood about their inflammatory status in acute coronary syndrome (ACS) patients with poor outcomes. Hence, we investigated the potential correlation between neutrophil inflammatory markers and the prognosis of ACS patients with/without diabetes and explored whether neutrophils demonstrate a unique inflammatory phenotype in patients experiencing an adverse in-hospital outcome. The study enrolled 229 ACS patients with or without diabetes. Poor evolution was defined as either death, left ventricular ejection fraction (LVEF) <40%, Killip Class 3/4, ventricular arrhythmias, or mechanical complications. Univariate and multivariate analyses were employed to identify clinical and paraclinical factors associated with in-hospital outcomes. Neutrophils isolated from fresh blood were investigated using qPCR, Western blot, enzymatic assay, and immunofluorescence. Poor evolution post-myocardial infarction (MI) was associated with increased number, activity, and inflammatory status of neutrophils, as indicated by significant increase of Erythrocyte Sedimentation Rate (ESR), C-reactive protein (CRP), fibrinogen, interleukin-1β (IL-1β), and, interleukin-6 (IL-6). Among the patients with complicated evolution, neutrophil activity had an important prognosis value for diabetics. Neutrophils from patients with unfavorable evolution revealed a pro-inflammatory phenotype with increased expression of CCL3, IL-1β, interleukin-18 (IL-18), S100A9, intracellular cell adhesion molecule-1 (ICAM-1), matrix metalloprotease (MMP-9), of molecules essential in reactive oxygen species (ROS) production p22phox and Nox2, and increased capacity to form neutrophil extracellular traps. Inflammation is associated with adverse short-term prognosis in acute ACS, and inflammatory biomarkers exhibit greater specificity in predicting short-term outcomes in diabetics. Moreover, neutrophils from patients with unfavorable evolution exhibit distinct inflammatory patterns, suggesting that alterations in the innate immune response in this subgroup may exert detrimental effects on disease progression.

Insights into the Novel Cardiac Biomarker in Acute Heart Failure: Mybp-C

(1) Background: Given its high cardiac specificity and its capacity to directly assess the cardiac function, cardiac myosin-binding protein (MyBP-C) is a promising biomarker in patients with acute heart failure (AHF). The aim of our study was to investigate the clinical utility of this novel marker for diagnosis and short-term prognosis in subjects with AHF. (2) Methods: We measured plasma levels of MyBP-C at admission in 49 subjects (27 patients admitted with AHF and 22 controls). (3) Results: The plasma concentration of MyBP-C was significantly higher in patients with AHF compared to controls (54.88 vs. 0.01 ng/L, p < 0.001). For 30-day prognosis, MyBP-C showed significantly greater AUC (0.972, p < 0.001) than NT-proBNP (0.849, p = 0.001) and hs-TnI (0.714, p = 0.047). In a multivariate logistic regression analysis, an elevated level of MyBP-C was the best independent predictor of 30-day mortality (OR = 1.08, p = 0.039) or combined death/recurrent 30-days rehospitalization (OR = 1.12, p = 0.014). (4) Conclusions: Our data show that circulating MyBP-C is a sensitive and cardiac-specific biomarker with potential utility for the accurate diagnosis and prognosis of AHF.

Galectin-3 (Gal-3) and the tissue inhibitor of matrix metalloproteinase (TIMP-2) as potential biomarkers for the clinical evolution of chronic Chagas cardiomyopathy

BACKGROUND

Chronic Chagas cardiomyopathy (CCC) is responsible for the highest morbidity and worst prognosis in Chagas disease patients. However, predicting factors that correlate with disease progression, morbidity, and mortality is challenging. It is necessary to have simple, quantitative, and economical risk biomarkers that add value to conventional methods and assist in the diagnosis and prognosis of patients with CCC or in evolution.

OBJECTIVES

We evaluated molecules related to cardiac remodeling and fibrosis, such as MMP-2, MMP-9, TIMP-2, TIMP-1, PICP, CTXI, and Gal-3, and correlated these biomarkers with echocardiographic variables (LVDD, LVEF, and E/e' ratio).

METHODS

Blood samples from Chagasic patients without apparent cardiopathy (WAC), CCC patients, and healthy individuals were used to perform plasma molecule dosages using Luminex or ELISA.

RESULTS

MMP-2 and TIMP-2 presented higher levels in CCC; in these patients, the inhibitory role of TIMP-2 over MMP-2 was reinforced. The ratio of MMP-2/TIMP-2 in WAC patients showed a bias in favor of the gelatinase pathway. MMP-9 and TIMP-1 showed higher levels in Chagas patients compared to healthy subjects. PICP and CTXI are not associated with cardiac deterioration in Chagas disease. Increased levels of Gal-3 are associated with worse cardiac function in CCC. Receiver operating characteristic (ROC) curve analysis identified Gal-3 and TIMP-2 as putative biomarkers to discriminate WAC from cardiac patients.

CONCLUSIONS

Among the molecules evaluated, Gal-3 and TIMP-2 have the potential to be used as biomarkers of cardiac remodeling and progressive myocardial fibrosis in Chagas disease.

Combining WGCNA and machine learning to identify mechanisms and biomarkers of ischemic heart failure development after acute myocardial infarction

Background

Ischemic heart failure (IHF) is a serious complication after acute myocardial infarction (AMI). Understanding the mechanism of IHF after AMI will help us conduct early diagnosis and treatment.

Methods

We obtained the AMI dataset GSE66360 and the IHF dataset GSE57338 from the GEO database, and screened overlapping genes common to both diseases through WGCNA analysis. Subsequently, we performed GO and KEGG enrichment analysis on overlapping genes to elucidate the common mechanism of AMI and IHF. Machine learning algorithms are also used to identify key biomarkers. Finally, we performed immune cell infiltration analysis on the dataset to further evaluate immune cell changes in AMI and IHF.

Results

We obtained 74 overlapping genes of AMI and IHF through WGCNA analysis, and the enrichment analysis results mainly focused on immune and inflammation-related mechanisms. Through the three machine learning algorithms of LASSO, RF and SVM-RFE, we finally obtained the four Hub genes of IL1B, TIMP2, IFIT3, and P2RY2, and verified them in the IHF dataset GSE116250, and the diagnostic model AUC = 0.907. The results of immune infiltration analysis showed that 8 types of immune cells were significantly different in AMI samples, and 6 types of immune cells were significantly different in IHF samples.

Conclusion

We explored the mechanism of IHF after AMI by WGCNA, enrichment analysis, and immune infiltration analysis. Four potential diagnostic candidate genes and therapeutic targets were identified by machine learning algorithms. This provides a new idea for the pathogenesis, diagnosis, and treatment of IHF after AMI.

Myocardial Matrix Hydrogels Mitigate Negative Remodeling and Improve Function in Right Heart Failure Model

This study evaluates the effectiveness of myocardial matrix (MM) hydrogels in mitigating negative right ventricular (RV) remodeling in a rat model of RV heart failure. The goal was to assess whether a hydrogel derived from either the right or left ventricle could promote cardiac repair. Injured rat right ventricles were injected with either RV-or left ventricular-derived MM hydrogels. Both hydrogels improved RV function and morphology and reduced negative remodeling. This study supports the potential of injectable biomaterial therapies for treating RV heart failure.

Elevated matrix Metalloproteinase-9 associated with reduced cerebellar perineuronal nets in female mice with toxoplasmosis

Brain infection by the parasite Toxoplasma gondii is thought to impair learning and memory, although the underlying mechanisms remain largely unknown. Recent studies suggest that perineuronal nets (PNNs) and their key regulator, matrix metalloproteinase-9 (MMP-9), have essential roles in synaptic plasticity associated with learning and memory. We investigated their roles in a chronic toxoplasmosis model using female mice. In mice with a high parasite burden of chronic infection, we found that MMP-9 expression was increased in the peripheral circulation and the brain. A correlation was found between the serum levels of MMP-9 and antibodies to the Toxoplasma matrix antigen MAG1, a surrogate marker for Toxoplasma tissue cysts in the brain. MMP-9 elevation was accompanied by increased expression of its endogenous regulators, TIMP-1 and NGAL. An increase in the levels of GSK-3α/β was observed, alongside a decrease in inhibitory GSK-3α/β (Ser-21/Ser-9) phosphorylation. MMP-9 expression was notably associated with the loss of PNNs but increased expression of the synaptic vesicle protein synaptophysin. There was a trend toward a negative correlation between MMP-9 and aggrecan expression, a critical PNN component. Together, these results suggest that chronic Toxoplasma infection can cause an increase in MMP-9 expression, resulting in the degradation of PNNs, which provides a possible mechanism for Toxoplasma-associated deficits in learning and memory.

IL-13 promotes functional recovery after myocardial infarction via direct signaling to macrophages

There is great interest in identifying signaling pathways that promote cardiac repair after myocardial infarction (MI). Prior studies suggest a beneficial role for IL-13 signaling in neonatal heart regeneration; however, the cell types mediating cardiac regeneration and the extent of IL-13 signaling in the adult heart after injury are unknown. We identified an abundant source of IL-13 and the related cytokine, IL-4, in neonatal cardiac type 2 innate lymphoid cells, but this phenomenon declined precipitously in adult hearts. Moreover, IL-13 receptor deletion in macrophages impaired cardiac function and resulted in larger scars early after neonatal MI. By using a combination of recombinant IL-13 administration and cell-specific IL-13 receptor genetic deletion models, we found that IL-13 signaling specifically to macrophages mediated cardiac functional recovery after MI in adult mice. Single transcriptomics revealed a subpopulation of cardiac macrophages in response to IL-13 administration. These IL-13-induced macrophages were highly efferocytotic and were identified by high IL-1R2 expression. Collectively, we elucidated a strongly proreparative role for IL-13 signaling directly to macrophages following cardiac injury. While this pathway is active in proregenerative neonatal stages, reactivation of macrophage IL-13 signaling is required to promote cardiac functional recovery in adults.

Bioresponsive Cytokine Delivery Responding to Matrix Metalloproteinases

Cytokines are regulated in acute and chronic inflammation, including rheumatoid arthritis (RA) and myocardial infarction (MI). However, the dynamic windows within which cytokine activity/inhibition is desirable in RA and MI change timely and locally during the disease. Therefore, traditional, static delivery regimens are unlikely to meet the idiosyncrasy of these highly dynamic pathophysiological and individual processes. Responsive delivery systems and biomaterials, sensing surrogate markers of inflammation (i.e., matrix metalloproteinases - MMPs) and answering with drug release, may present drug activity at the right time, manner, and place. This article discusses MMPs as surrogate markers for disease activity in RA and MI to clock drug discharge to MMP concentration profiles from MMP-responsive drug delivery systems and biomaterials.

Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes

OBJECTIVE

A wide range of cardiac diseases is associated with inflammation. "Inflamed" heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process.

METHODS AND RESULTS

In mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect.

CONCLUSION

Activation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

Selected Cytokines and Metalloproteinases in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a collective term for two diseases: ulcerative colitis (UC) and Crohn's disease (CD). There are many factors, e.g., genetic, environmental and immunological, that increase the likelihood of these diseases. Indicators of IBDs include extracellular matrix metalloproteinases (MMPs). The aim of this review is to present data on the role of selected cytokines and metalloproteinases in IBD. In recent years, more and more transcriptomic studies are emerging. These studies are improving the characterization of the cytokine microenvironment inside inflamed tissue. It is observed that the levels of several cytokines are consistently increased in inflamed tissue in IBD, both in UC and CD. This review shows that MMPs play a major role in the pathology of inflammatory processes, cancer, and IBD. IBD-associated inflammation is associated with increased expression of MMPs and reduced ability of tissue inhibitors of metalloproteinases (TIMPs) to inhibit their action. In IBD patients in tissues that are inflamed, MMPs are produced in excess and TIMP activity is not sufficient to block MMPs. This review is based on our personal selection of the literature that was retrieved by a selective search in PubMed using the terms "Inflammatory bowel disease" and "pathogenesis of Inflammatory bowel diseases" that includes systematic reviews, meta-analyses, and clinical trials. The involvement of the immune system in the pathophysiology of IBD is reviewed in terms of the role of the cytokines and metalloproteinases involved.

The role of cardiac resident macrophage in cardiac aging

Advancements in longevity research have provided insights into the impact of cardiac aging on the structural and functional aspects of the heart. Notable changes include the gradual remodeling of the myocardium, the occurrence of left ventricular hypertrophy, and the decline in both systolic and diastolic functions. Macrophages, a type of immune cell, play a pivotal role in innate immunity by serving as vigilant agents against pathogens, facilitating wound healing, and orchestrating the development of targeted acquired immune responses. Distinct subsets of macrophages are present within the cardiac tissue and demonstrate varied functions in response to myocardial injury. The differentiation of cardiac macrophages according to their developmental origin has proven to be a valuable strategy in identifying reparative macrophage populations, which originate from embryonic cells and reside within the tissue, as well as inflammatory macrophages, which are derived from monocytes and recruited to the heart. These subsets of macrophages possess unique characteristics and perform distinct functions. This review aims to summarize the current understanding of the roles and phenotypes of cardiac macrophages in various conditions, including the steady state, aging, and other pathological conditions. Additionally, it will highlight areas that require further investigation to expand our knowledge in this field.

Effects of Doxorubicin on Extracellular Matrix Regulation in Primary Cardiac Fibroblasts from Mice

OBJECTIVE

Doxorubicin (DOX) is a highly effective chemotherapeutic used to treat many adult and pediatric cancers. However, its use is limited due to a dose-dependent cardiotoxicity, which can lead to lethal cardiomyopathy. In contrast to the extensive research efforts on toxic effects of DOX in cardiomyocytes, its effects and mechanisms on cardiac extracellular matrix (ECM) homeostasis and remodeling are poorly understood. In this study, we examined the potential effects of DOX on cardiac ECM to further our mechanistic understanding of DOX-induced cardiotoxicity.

RESULTS

DOX-induced significant down-regulation of several ECM related genes in primary cardiac fibroblasts, including Adamts1, Adamts5, Col4a1, Col4a2, Col5a1, Fbln1, Lama2, Mmp11, Mmp14, Postn, and TGFβ. Quantitative proteomics analysis revealed significant global changes in the fibroblast proteome following DOX treatment. A pathway analysis using iPathwayGuide of the differentially expressed proteins revealed changes in a list of biological pathways that involve cell adhesion, cytotoxicity, and inflammation. An apparent increase in Picrosirius red staining indicated that DOX-induced an increase in collagen production in cardiac primary fibroblasts after 3-day treatment. No significant changes in collagen organization nor glycoprotein production were observed.

Enzyme-Responsive Nanoparticles for the Targeted Delivery of an MMP Inhibitor to Acute Myocardial Infarction

Herein, we have developed a drug-loaded matrix metalloproteinase (MMP)-responsive micellar nanoparticle (NP) intended for minimally invasive intravenous injection during the acute phase of myocardial infarction (MI) and prolonged retention in the heart for small-molecule drug delivery. Peptide-polymer amphiphiles (PPAs) bearing a small-molecule MMP inhibitor (MMPi), PD166793, were synthesized via ring-opening metathesis polymerization (ROMP) and formulated into spherical micelles by transitioning to aqueous solution. The resulting micellar NPs underwent MMP-induced aggregation, demonstrating enzyme responsiveness. Using a rat MI model, we observed that these NPs were capable of successfully extravasating into the infarcted region of the heart where they were retained due to the active, enzyme-mediated targeting, remaining detectable after 1 week post administration without increasing macrophage recruitment. Furthermore, in vitro studies show that these NPs demonstrated successful drug release following MMP treatment and maintained drug bioactivity as evidenced by comparable MMP inhibition to free MMPi. This work establishes a targeted NP platform for delivering small-molecule therapeutics to the heart after MI, opening possibilities for myocardial infarction treatment.

Catch your breath: The protective role of the angiotensin AT2 receptor for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease whereby excessive deposition of extracellular matrix proteins (ECM) ultimately leads to respiratory failure. While there have been advances in pharmacotherapies for pulmonary fibrosis, IPF remains an incurable and irreversible disease. There remains an unmet clinical need for treatments that reverse fibrosis, or at the very least have a more tolerable side effect profile than currently available treatments. Transforming growth factor β1(TGFβ1) is considered the main driver of fibrosis in IPF. However, as our understanding of the role of the pulmonary renin-angiotensin system (PRAS) in the pathogenesis of IPF increases, it is becoming clear that targeting angiotensin receptors represents a potential novel treatment strategy for IPF - in particular, via activation of the anti-fibrotic angiotensin type 2 receptor (AT2R). This review describes the current understanding of the pathophysiology of IPF and the mediators implicated in its pathogenesis; focusing on TGFβ1, angiotensin II and related peptides in the PRAS and their contribution to fibrotic processes in the lung. Preclinical and clinical assessment of currently available AT2R agonists and the development of novel, highly selective ligands for this receptor will also be described, with a focus on compound 21, currently in clinical trials for IPF. Collectively, this review provides evidence of the potential of AT2R as a novel therapeutic target for IPF.

Changes in Cardiovascular and Renal Biomarkers Associated with SGLT2 Inhibitors Treatment in Patients with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus is a major health problem worldwide with a steadily increasing prevalence reaching epidemic proportions. The major concern is the increased morbidity and mortality due to diabetic complications. Traditional but also nontraditional risk factors have been proposed to explain the pathogenesis of type 2 diabetes mellitus and its complications. Hyperglycemia has been considered an important risk factor, and the strict glycemic control can have a positive impact on microangiopathy but not macroangiopathy and its related morbidity and mortality. Thus, the therapeutic algorithm has shifted focus from a glucose-centered approach to a strategy that now emphasizes target-organ protection. Sodium-glucose transporter 2 inhibitors is an extremely important class of antidiabetic medications that, in addition to their glucose lowering effect, also exhibit cardio- and renoprotective effects. Various established and novel biomarkers have been described, reflecting kidney and cardiovascular function. In this review, we investigated the changes in established but also novel biomarkers of kidney, heart and vascular function associated with sodium-glucose transporter 2 inhibitors treatment in patients with type 2 diabetes mellitus.

Altered Peripheral Blood Gene Expression in Childhood Cancer Survivors With Anthracycline-Induced Cardiomyopathy - A COG-ALTE03N1 Report

Background Anthracycline-induced cardiomyopathy is a leading cause of premature death in childhood cancer survivors, presenting a need to understand the underlying pathogenesis. We sought to examine differential blood-based mRNA expression profiles in anthracycline-exposed childhood cancer survivors with and without cardiomyopathy. Methods and Results We designed a matched case-control study (Children's Oncology Group-ALTE03N1) with mRNA sequencing on total RNA from peripheral blood in 40 anthracycline-exposed survivors with cardiomyopathy (cases) and 64 matched survivors without (controls). DESeq2 identified differentially expressed genes. Ingenuity Pathway Analyses (IPA) and Gene Set Enrichment Analyses determined the potential roles of altered genes in biological pathways. Functional validation was performed by gene knockout in human-induced pluripotent stem cell-derived cardiomyocytes using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) technology. Median age at primary cancer diagnosis for cases and controls was 8.2 and 9.7 years, respectively. Thirty-six differentially expressed genes with fold change ≥±2 were identified; 35 were upregulated. IPA identified "hepatic fibrosis" and "iron homeostasis" pathways to be significantly modulated by differentially expressed genes, including toxicology functions of myocardial infarction, cardiac damage, and cardiac dilation. Leading edge analysis from Gene Set Enrichment Analyses identified lactate dehydrogenase A (LDHA) and cluster of differentiation 36 (CD36) genes to be significantly upregulated in cases. Interleukin 1 receptor type 1, 2 (IL1R1, IL1R2), and matrix metalloproteinase 8, 9 (MMP8, MMP9) appeared in multiple canonical pathways. LDHA-knockout human-induced pluripotent stem cell-derived cardiomyocytes showed increased sensitivity to doxorubicin. Conclusions We identified differential mRNA expression profiles in peripheral blood of anthracycline-exposed childhood cancer survivors with and without cardiomyopathy. Upregulation of LDHA and CD36 genes suggests metabolic perturbations in a failing heart. Dysregulation of proinflammatory cytokine receptors IL1R1 and IL1R2 and matrix metalloproteinases, MMP8 and MMP9 indicates structural remodeling that accompanies the clinical manifestation of symptomatic cardiotoxicity.

Macrophage colony-stimulating factor ameliorates myocardial injury in mice after myocardial infarction by regulating cardiac macrophages through the P2X7R/NLRP3/IL-1β signal pathway

Aims

To investigate the effects of M-CSF on myocardial injury in mice after MI by regulating different types of cardiac macrophages through the P2X7R/NLRP3/IL-1β signal pathway.

Methods

A total of 60 C57BL/6J WT mice were used, with the Sham Group subjected to ligation without ligation through the LAD, the MI model was prepared by ligation of the LAD in the MC Group and MM Group, with the M-CSF reagent (500 μg/kg/d) being given an intraperitoneal injection for the first 5 days after surgery in the MM Group. All mice were fed in a barrier environment for 1 week. After the study, myocardial tissues were collected and IL-4, IL-6, IL-10, TNF-α, MCP-1, IFN-α, ANP, BNP, β-MHC, Collage I, Collage III, P2X7R, NLRP3, IL-1β, Bax, Caspase 3, C-Casp 3, Bcl-2, M1/2 macrophage, the apoptosis of cardiomyocytes, and the collagen deposition were detected.

Results

The inflammatory response was significantly lower in the MM Group, the cardiomyocyte apoptosis, fibrosis, and hypertrophy were inhibited compared to the MC Group, and the levels of P2X7R, NLRP3, and IL-1β were also statistically lower in the MM Group. Additionally, the expression of M2 macrophages increased in the MM Group while the M1 macrophages statistically decreased compared to the MC Group.

Conclusion

M-CSF can significantly increase the expression of M2 macrophage and reduce the level of M1 macrophage by inhibiting the levels of NLRP3/IL-1β-related proteins, thereby inhibiting inflammation, ameliorating reducing myocardial hypertrophy, apoptosis, and fibrosis, improve myocardial injury in mice after MI.

Mechanism of heart failure after myocardial infarction

Despite the widespread use of early revascularization and drugs to regulate the neuroendocrine system, the impact of such measures on alleviating the development of heart failure (HF) after myocardial infarction (MI) remains limited. Therefore, it is important to discuss the development of new therapeutic strategies to prevent or reverse HF after MI. This requires a better understanding of the potential mechanisms involved. HF after MI is the result of complex pathophysiological processes, with adverse ventricular remodeling playing a major role. Adverse ventricular remodeling refers to the heart's adaptation in terms of changes in ventricular size, shape, and function under the influence of various regulatory factors, including the mechanical, neurohormonal, and cardiac inflammatory immune environments; ischemia/reperfusion injury; energy metabolism; and genetic correlation factors. Additionally, unique right ventricular dysfunction can occur secondary to ischemic shock in the surviving myocardium. HF after MI may also be influenced by other factors. This review summarizes the main pathophysiological mechanisms of HF after MI and highlights sex-related differences in the prognosis of patients with acute MI. These findings provide new insights for guiding the development of targeted treatments to delay the progression of HF after MI and offering incremental benefits to existing therapies.

Changes in the extracellular matrix at microvascular obstruction area after reperfused myocardial infarction: A morphometric study

BACKGROUND

Extracellular matrix (ECM) suffers substantial alterations after myocardial infarction (MI), including the invasion of leukocyte subtypes. Despite a complete reopening at epicardial level, hypoperfusion within the infarcted myocardium, known as microvascular obstruction (MVO), occurs and exerts a negative impact on ventricular remodeling. In this study, ECM composition at MVO regions was described using a morphometric analysis.

METHODS

MI was induced in female swine (n = 10) by transitory 90-minute coronary occlusion followed by seven days of reperfusion. Prior to euthanasia, intracoronary thioflavin-S was infused. Within the infarcted myocardium, regions displaying MVO (thioflavin-S-) or no MVO (thioflavin-S+) were isolated and stained to morphometrically compare ECM composition.

RESULTS

As reflected by cell invasion through ECM, areas with MVO displayed an enlarged presence of neutrophils and lymphocytes, whilst no differences in the amount of macrophages and myofibroblasts were detected compared to infarcted myocardium without MVO. Indeed, those regions with macroscopic MVO showed lower capillary density than areas without MVO. Lastly, a significant reduction in the extension of total collagen, type I, but not type III, collagen, laminin, and fibronectin together with an augmentation of polysaccharides were noted in areas showing MVO compared to those without microvascular injury.

CONCLUSIONS

ECM composition in infarcted regions with MVO isolated from female swine displays a higher presence of inflammatory infiltrate and polysaccharides as well as reduced number of microvessels and collagen content compared to those areas without microvascular hypoperfusion. These characteristics might underlie the development of adverse ventricular remodeling in MI patients with extensive MVO.

Effects of PCSK9 inhibitors on coronary microcirculation, inflammation and cardiac function in patients with CHD after PCI: a protocol for systematic review and meta-analysis

INTRODUCTION

Coronary heart disease (CHD) is one of the common cardiovascular diseases that seriously jeopardise human health, and endothelial inflammation and dyslipidaemia are the initiating links leading to its occurrence. Percutaneous coronary intervention (PCI) is one of the most effective surgical treatments for CHD with narrowed or blocked blood vessels, which can quickly unblock the blocked vessels and restore coronary blood supply. However, most patients may experience coronary microcirculation disorders (CMDs) and decreased cardiac function after PCI treatment, which directly affects the efficacy of PCI and the prognosis of patients. Preprotein converting enzyme subtilisin/Kexin 9 (PCSK9) inhibitors are novel pleiotropy lipid-lowering drug with dual anti-inflammation and lipid-lowering effects, and represent a new clinical pathway for rapid correction of dyslipidaemia. Therefore, we designed this protocol to systematically evaluate the effects of PCSK9 inhibitors on coronary microcirculation and cardiac function in patients with CHD after PCI, and to provide high-quality evidence-based evidence for the clinical application of PCSK9 inhibitors.

METHODS AND ANALYSIS

This protocol is reported strictly in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols Guidelines. We will search PubMed, EMBASE, Web of Science and three Chinese databases (CNKI, Wanfang and VIP database) according to preset search strategies, without language and publication data restrictions. We will work with manual retrieval to screen references that have been included in the literature. Google Scholar will be used to search for grey literature. The final included literature must meet the established inclusion criteria. Titles, abstracts and full text will be extracted independently by two reviewers, and disagreements will be resolved through discussion or the involvement of a third reviewer. Extracted data will be analysed using Review Manager V.5.3. The Cochrane Risk of Bias Tool will be used to evaluate the risk of bias. Publication bias will be assessed by funnel plots. Heterogeneity will be assessed by I2 test and subgroup analyses will be used to further investigate potential sources of heterogeneity. The quality of the literature will be assessed by GRADE score. This protocol will start in January 2026 and end in December 2030.

ETHICS AND DISSEMINATION

This study is a systematic review of published literature data and no special ethical approval was required.

PROSPERO REGISTRATION NUMBER

CRD42022346189.

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.

Effects of electrospun fibers containing ascorbic acid on oxidative stress reduction for cardiac tissue engineering

Tissue engineering provides promise for regeneration of cardiac tissue following myocardial infarction. However, the harsh microenvironment of the infarct hampers the efficacy of regenerative therapies. Ischemia-reperfusion injury dramatically increases the levels of reactive oxygen species (ROS) within the infarcted area, causing a cascade of further cellular injury. Implantable tissue engineered grafts can target this oxidative stress by delivering pharmaceutical compounds directly into the diseased tissue. Herein, we successfully fabricated electrospun polycaprolactone (PCL) fibers containing varying concentrations of ascorbic acid, a potent antioxidant well known for its ROS-scavenging capabilities. The antioxidant scaffolds displayed significantly improved scavenging of DPPH radicals, superoxide anions and hydroxyl radicals, in a dose dependent manner. Mechanical properties testing indicated that incorporation of ascorbic acid enhanced the strength and Young's modulus of the material, correlating with a moderate but non-significant increase in the crystallinity. Moreover, the scaffolds supported adhesion and maintained survival of human umbilical vein endothelial cells in vitro, indicating good cytocompatibility. These results provide motivation for the use of ascorbic acid-containing fibrous scaffolds to regulate the highly oxidative microenvironment following myocardial infarction.

Sex Differences in Therapies against Myocardial Ischemia-Reperfusion Injury: From Basic Science to Clinical Perspectives

Mortality from myocardial infarction (MI) has declined over recent decades, which could be attributed in large part to improved treatment methods. Early reperfusion is the cornerstone of current MI treatment. However, reoxygenation via restored blood flow induces further damage to the myocardium, leading to ischemia-reperfusion injury (IRI). While experimental studies overwhelmingly demonstrate that females experience greater functional recovery from MI and decreased severity in the underlying pathophysiological mechanisms, the outcomes of MI with subsequent reperfusion therapy, which is the clinical correlate of myocardial IRI, are generally poorer for women compared with men. Distressingly, women are also reported to benefit less from current guideline-based therapies compared with men. These seemingly contradicting outcomes between experimental and clinical studies show a need for further investigation of sex-based differences in disease pathophysiology, treatment response, and a sex-specific approach in the development of novel therapeutic methods against myocardial IRI. In this literature review, we summarize the current knowledge on sex differences in the underlying pathophysiological mechanisms of myocardial IRI, including the roles of sex hormones and sex chromosomes. Furthermore, we address sex differences in pharmacokinetics, pharmacodynamics, and pharmacogenetics of current drugs prescribed to limit myocardial IRI. Lastly, we highlight ongoing clinical trials assessing novel pharmacological treatments against myocardial IRI and sex differences that may underlie the efficacy of these new therapeutic approaches.

RNA-Binding Proteins as Critical Post-Transcriptional Regulators of Cardiac Regeneration

Myocardial injury causes death to cardiomyocytes and leads to heart failure. The adult mammalian heart has very limited regenerative capacity. However, the heart from early postnatal mammals and from adult lower vertebrates can fully regenerate after apical resection or myocardial infarction. Thus, it is of particular interest to decipher the mechanism underlying cardiac regeneration that preserves heart structure and function. RNA-binding proteins, as key regulators of post-transcriptional gene expression to coordinate cell differentiation and maintain tissue homeostasis, display dynamic expression in fetal and adult hearts. Accumulating evidence has demonstrated their importance for the survival and proliferation of cardiomyocytes following neonatal and postnatal cardiac injury. Functional studies suggest that RNA-binding proteins relay damage-stimulated cell extrinsic or intrinsic signals to regulate heart regenerative capacity by reprogramming multiple molecular and cellular processes, such as global protein synthesis, metabolic changes, hypertrophic growth, and cellular plasticity. Since manipulating the activity of RNA-binding proteins can improve the formation of new cardiomyocytes and extend the window of the cardiac regenerative capacity in mammals, they are potential targets of therapeutic interventions for cardiovascular disease. This review discusses our evolving understanding of RNA-binding proteins in regulating cardiac repair and regeneration, with the aim to identify important open questions that merit further investigations.

Matrix metalloproteinase-2 proteolyzes mitofusin-2 and impairs mitochondrial function during myocardial ischemia-reperfusion injury

During myocardial ischemia and reperfusion (IR) injury matrix metalloproteinase-2 (MMP-2) is rapidly activated in response to oxidative stress. MMP-2 is a multifunctional protease that cleaves both extracellular and intracellular proteins. Oxidative stress also impairs mitochondrial function which is regulated by different proteins, including mitofusin-2 (Mfn-2), which is lost in IR injury. Oxidative stress and mitochondrial dysfunction trigger the NLRP3 inflammasome and the innate immune response which invokes the de novo expression of an N-terminal truncated isoform of MMP-2 (NTT-MMP-2) at or near mitochondria. We hypothesized that MMP-2 proteolyzes Mfn-2 during myocardial IR injury, impairing mitochondrial function and enhancing the inflammasome response. Isolated hearts from mice subjected to IR injury (30 min ischemia/40 min reperfusion) showed a significant reduction in left ventricular developed pressure (LVDP) compared to aerobically perfused hearts. IR injury increased MMP-2 activity as observed by gelatin zymography and increased degradation of troponin I, an intracellular MMP-2 target. MMP-2 preferring inhibitors, ARP-100 or ONO-4817, improved post-ischemic recovery of LVDP compared to vehicle perfused IR hearts. In muscle fibers isolated from IR hearts the rates of mitochondrial oxygen consumption and ATP production were impaired compared to those from aerobic hearts, whereas ARP-100 or ONO-4817 attenuated these reductions. IR hearts showed higher levels of NLRP3, cleaved caspase-1 and interleukin-1β in the cytosolic fraction, while the mitochondria-enriched fraction showed reduced levels of Mfn-2, compared to aerobic hearts. ARP-100 or ONO-4817 attenuated these changes. Co-immunoprecipitation showed that MMP-2 is associated with Mfn-2 in aerobic and IR hearts. ARP-100 or ONO-4817 also reduced infarct size and cell death in hearts subjected to 45 min ischemia/120 min reperfusion. Following myocardial IR injury, impaired contractile function and mitochondrial respiration and elevated inflammasome response could be attributed, at least in part, to MMP-2 activation, which targets and cleaves mitochondrial Mfn-2. Inhibition of MMP-2 activity protects against cardiac contractile dysfunction in IR injury in part by preserving Mfn-2 and suppressing inflammation.

Matrix Metalloproteinases and Heart Transplantation-A Pathophysiological and Clinical View

Heart transplantation is undergoing a continuous development, with rates of success increasing substantially due to advances in immunosuppressive therapy and surgical techniques. The most worrying complication occurring after cardiac transplantation is graft rejection, a phenomenon that is much affected by matrix metalloproteinases (MMPs), with the role of these proteases in the cardiac remodeling process being well established in the literature. A detailed investigation of the association between MMPs and cardiac rejection is necessary for the future development of more targeted therapies in transplanted patients, and to discover prognostic serum and immunohistochemical markers that will lead to more organized therapeutic management in these patients. The aim of this review is therefore to highlight the main MMPs relevant to cardiovascular pathology, with particular emphasis on those involved in complications related to heart transplantation, including cardiac graft rejection.

Comparative Analysis of Whole Transcriptome Profiles in Septic Cardiomyopathy: Insights from CLP- and LPS-Induced Mouse Models

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, with septic cardiomyopathy being a common and severe complication. Despite its significant clinical impact, the molecular mechanisms underlying sepsis-induced cardiomyopathy (SICM) remain incompletely understood. In this study, we performed a comparative analysis of whole transcriptome profiles using RNA sequencing in mouse hearts in two widely used mouse models of septic cardiomyopathy. CLP-induced sepsis was achieved by surgical cecal ligation and puncture, while LPS-induced sepsis was induced using a 5 mg/kg intraperitoneal (IP) injection of lipopolysaccharide (LPS). For consistency, we utilized sham-operated mice as the control for septic models. Our aim was to identify key genes and pathways involved in the development of septic cardiomyopathy and to evaluate the similarities and differences between the two models. Our findings demonstrated that both the CLP and lipopolysaccharide LPS methods could induce septic heart dysfunction within 24 h. We identified common transcriptional regulatory regions in the septic hearts of both models, such as Nfkb1, Sp1, and Jun. Moreover, differentially expressed genes (DEGs) in comparison to control were involved in shared pathways, including regulation of inflammatory response, regulation of reactive oxygen species metabolic process, and the JAK-STAT signaling pathway. However, each model presented distinctive whole transcriptome expression profiles and potentially diverse pathways contributing to sepsis-induced heart failure. This extensive comparison enhances our understanding of the molecular basis of septic cardiomyopathy, providing invaluable insights. Accordingly, our study also contributes to the pursuit of effective and personalized treatment strategies for SICM, highlighting the importance of considering the specific causative factors.

Don't go breakin' my heart: cardioprotective alterations to the mechanical and structural properties of reperfused myocardium during post-infarction inflammation

Myocardial infarctions (MIs) kickstart an intense inflammatory response resulting in extracellular matrix (ECM) degradation, wall thinning, and chamber dilation that leaves the heart susceptible to rupture. Reperfusion therapy is one of the most effective strategies for limiting adverse effects of MIs, but is a challenge to administer in a timely manner. Late reperfusion therapy (LRT; 3 + hours post-MI) does not limit infarct size, but does reduce incidences of post-MI rupture and improves long-term patient outcomes. Foundational studies employing LRT in the mid-twentieth century revealed beneficial reductions in infarct expansion, aneurysm formation, and left ventricle dysfunction. The mechanism by which LRT acts, however, is undefined. Structural analyses, relying largely on one-dimensional estimates of ECM composition, have found few differences in collagen content between LRT and permanently occluded animal models when using homogeneous samples from infarct cores. Uniaxial testing, on the other hand, revealed slight reductions in stiffness early in inflammation, followed soon after by an enhanced resistance to failure for cases of LRT. The use of one-dimensional estimates of ECM organization and gross mechanical function have resulted in a poor understanding of the infarct's spatially variable mechanical and structural anisotropy. To resolve these gaps in literature, future work employing full-field mechanical, structural, and cellular analyses is needed to better define the spatiotemporal post-MI alterations occurring during the inflammatory phase of healing and how they are impacted following reperfusion therapy. In turn, these studies may reveal how LRT affects the likelihood of rupture and inspire novel approaches to guide scar formation.

Oxaliplatin-induced cardiotoxicity in mice is connected to the changes in energy metabolism in the heart tissue

Oxaliplatin is a platinum-based alkylating chemotherapeutic agent used for cancer treatment. At high cumulative dosage, the negative effect of oxaliplatin on the heart becomes evident and is linked to a growing number of clinical reports. The aim of this study was to determine how chronic oxaliplatin treatment causes the changes in energy-related metabolic activity in the heart that leads to cardiotoxicity and heart damage in mice. C57BL/6 male mice were treated with a human equivalent dosage of intraperitoneal oxaliplatin (0 and 10 mg/kg) once a week for eight weeks. During the treatment, mice were followed for physiological parameters, ECG, histology and RNA sequencing of the heart. We identified that oxaliplatin induces strong changes in the heart and affects the heart's energy-related metabolic profile. Histological post-mortem evaluation identified focal myocardial necrosis infiltrated with a small number of associated neutrophils. Accumulated doses of oxaliplatin led to significant changes in gene expression related to energy related metabolic pathways including fatty acid (FA) oxidation, amino acid metabolism, glycolysis, electron transport chain, and NAD synthesis pathway. At high accumulative doses of oxaliplatin, the heart shifts its metabolism from FAs to glycolysis and increases lactate production. It also leads to strong overexpression of genes in NAD synthesis pathways such as Nmrk2. Changes in gene expression associated with energy metabolic pathways can be used to develop diagnostic methods to detect oxaliplatin-induced cardiotoxicity early on as well as therapy to compensate for the energy deficit in the heart to prevent heart damage.

IGF2BP3 promotes adult myocardial regeneration by stabilizing MMP3 mRNA through interaction with m6A modification

Myocardial infarction that causes damage to heart muscle can lead to heart failure. The identification of molecular mechanisms promoting myocardial regeneration represents a promising strategy to improve cardiac function. Here we show that IGF2BP3 plays an important role in regulating adult cardiomyocyte proliferation and regeneration in a mouse model of myocardial infarction. IGF2BP3 expression progressively decreases during postnatal development and becomes undetectable in the adult heart. However, it becomes upregulated after cardiac injury. Both gain- and loss-of-function analyses indicate that IGF2BP3 regulates cardiomyocyte proliferation in vitro and in vivo. In particular, IGF2BP3 promotes cardiac regeneration and improves cardiac function after myocardial infarction. Mechanistically, we demonstrate that IGF2BP3 binds to and stabilizes MMP3 mRNA through interaction with N⁶-methyladenosine modification. The expression of MMP3 protein is also progressively downregulated during postnatal development. Functional analyses indicate that MMP3 acts downstream of IGF2BP3 to regulate cardiomyocyte proliferation. These results suggest that IGF2BP3-mediated post-transcriptional regulation of extracellular matrix and tissue remodeling contributes to cardiomyocyte regeneration. They should help to define therapeutic strategy for ameliorating myocardial infarction by inducing cell proliferation and heart repair.

Vision for Ratiometric Nanoprobes: In Vivo Noninvasive Visualization and Readout of Physiological Hallmarks

Lesion areas are distinguished from normal tissues surrounding them by distinct physiological characteristics. These features serve as biological hallmarks with which targeted biomedical imaging of the lesion sites can be achieved. Although tremendous efforts have been devoted to providing smart imaging probes with the capability of visualizing the physiological hallmarks at the molecular level, the majority of them are merely able to derive anatomical information from the tissues of interest, and thus are not suitable for taking part in in vivo quantification of the biomarkers. Recent advances in chemical construction of advanced ratiometric nanoprobes (RNPs) have enabled a horizon for quantitatively monitoring the biological abnormalities in vivo. In contrast to the conventional probes whose dependency of output on single-signal profiles restricts them from taking part in quantitative practices, RNPs are designed to provide information in two channels, affording a self-calibration opportunity to exclude the analyte-independent factors from the outputs and address the issue. Most of the conventional RNPs have encountered several challenges regarding the reliability and sufficiency of the obtained data for high-performance imaging. In this Review, we have summarized the recent progresses in developing highly advanced RNPs with the capabilities of deriving maximized information from the lesion areas of interest as well as adapting themselves to the complex biological systems in order to minimize microenvironmental-induced falsified signals. To provide a better outlook on the current advanced RNPs, nanoprobes based on optical, photoacoustic, and magnetic resonance imaging modalities for visualizing a wide range of analytes such as pH, reactive species, and different derivations of amino acids have been included. Furthermore, the physicochemical properties of the RNPs, the major constituents of the nanosystems and the analyte recognition mechanisms have been introduced. Moreover, the alterations in the values of the ratiometric signal in response to the analyte of interest as well as the time at which the highest value is achieved, have been included for most of RNPs discussed in this Review. Finally, the challenges as well as future perspectives in the field are discussed.

The MEF2A transcription factor interactome in cardiomyocytes

Transcriptional regulators encoded by the Myocyte Enhancer Factor 2 (MEF2) gene family play a fundamental role in cardiac development, homeostasis and pathology. Previous studies indicate that MEF2A protein-protein interactions serve as a network hub in several cardiomyocyte cellular processes. Based on the idea that interactions with regulatory protein partners underly the diverse roles of MEF2A in cardiomyocyte gene expression, we undertook a systematic unbiased screen of the MEF2A protein interactome in primary cardiomyocytes using an affinity purification-based quantitative mass spectrometry approach. Bioinformatic processing of the MEF2A interactome revealed protein networks involved in the regulation of programmed cell death, inflammatory responses, actin dynamics and stress signaling in primary cardiomyocytes. Further biochemical and functional confirmation of specific protein-protein interactions documented a dynamic interaction between MEF2A and STAT3 proteins. Integration of transcriptome level data from MEF2A and STAT3-depleted cardiomyocytes reveals that the balance between MEF2A and STAT3 activity exerts a level of executive control over the inflammatory response and cardiomyocyte cell survival and experimentally ameliorates Phenylephrine induced cardiomyocyte hypertrophy. Lastly, we identified several MEF2A/STAT3 co-regulated genes, including the MMP9 gene. Herein, we document the cardiomyocyte MEF2A interactome, which furthers our understanding of protein networks involved in the hierarchical control of normal and pathophysiological cardiomyocyte gene expression in the mammalian heart.

Identification of potential biomarkers and therapeutic targets for posttraumatic acute respiratory distress syndrome

BACKGROUND

Despite improved supportive care, posttraumatic acute respiratory distress syndrome (ARDS) mortality has improved very little in recent years. Additionally, ARDS diagnosis is delayed or missed in many patients. We analyzed co-differentially expressed genes (co-DEGs) to explore the relationships between severe trauma and ARDS to reveal potential biomarkers and therapeutic targets for posttraumatic ARDS.

METHODS

Two gene expression datasets (GSE64711 and GSE76293) were downloaded from the Gene Expression Omnibus. The GSE64711 dataset included a subset of 244 severely injured trauma patients and 21 healthy controls. GSE76293 specimens were collected from 12 patients with ARDS who were recruited from trauma intensive care units and 11 age- and sex-matched healthy volunteers. Trauma DEGs and ARDS DEGs were identified using the two datasets. Subsequently, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein-protein interaction network analyses were performed to elucidate the molecular functions of the DEGs. Then, hub genes of the co-DEGs were identified. Finally, to explore whether posttraumatic ARDS and septic ARDS are common targets, we included a third dataset (GSE100159) for corresponding verification.

RESULTS

90 genes were upregulated and 48 genes were downregulated in the two datasets and were therefore named co-DEGs. These co-DEGs were significantly involved in multiple inflammation-, immunity- and neutrophil activation-related biological processes. Ten co-upregulated hub genes (GAPDH, MMP8, HGF, MAPK14, LCN2, CD163, ENO1, CD44, ARG1 and GADD45A) and five co-downregulated hub genes (HERC5, IFIT2, IFIT3, RSAD2 and IFIT1) may be considered potential biomarkers and therapeutic targets for posttraumatic ARDS. Through the verification of the third dataset, posttraumatic ARDS may have its own unique targets worthy of further exploration.

CONCLUSION

This exploratory analysis supports a relationship between trauma and ARDS pathophysiology, specifically in relationship to the identified hub genes. These data may serve as potential biomarkers and therapeutic targets for posttraumatic ARDS.

Protocatechuic acid reverses myocardial infarction mediated by β-adrenergic agonist via regulation of Nrf2/HO-1 pathway, inflammatory, apoptotic, and fibrotic events

Myocardial infarction (MI) is an instant ischemic death of cardiomyocytes that remains a major global cause of mortalities. MI is accompanied by oxidative, inflammatory, apoptotic, and fibrotic insults. Protocatechuic acid (PCA) is a polyphenolic compound with various potent biological activities. In this study, we explored the possible cardioprotective role of PCA against isoproterenol (ISO)-mediated MI. Rats were either injected with ISO (85 mg/kg, subcutaneously) or pretreated with PCA (100 or 200 mg/kg, orally). PCA supplementation markedly normalized ISO-induced disturbed cardiac function markers (creatine kinase-MB, lactate dehydrogenase, and troponin T). Notably, PCA administration exerted remarkable increases in glutathione and its derived enzymes, superoxide dismutase, and catalase, as well as decreases in malondialdehyde and nitric oxide levels in the injured cardiac tissue. The molecular findings validated the augmented cellular antioxidative capacity by PCA via increasing the gene expressions of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1. The cardioprotective efficacy of PCA extended to suppress cardiac inflammation as demonstrated by the decreased levels of tumor necrosis factor-alpha, interleukin-1 beta, and nuclear factor kappa B. Additionally, PCA prevented cardiomyocyte loss and fibrosis by decreasing Bax, caspase-3, transforming growth factor-β1 and matrix metalloproteinase-9, and enhancing B-cell lymphoma 2 and tissue inhibitors of metalloproteinase-3. The cardiac histological screening further confirmed the PCA's protective action. The obtained data recommend PCA as an alternative therapeutic agent to attenuate the molecular, biochemical, and histological alterations associated with MI development.

Meibomian Gland Dysfunction: A Route of Ocular Graft-Versus-Host Disease Progression That Drives a Vicious Cycle of Ocular Surface Inflammatory Damage

PURPOSE

To investigate the role of aggressive meibomian gland dysfunction (MGD) in the immune pathogenesis of ocular graft-vs-host disease (GVHD).

METHODS

In mice, an allogeneic GVHD model was established by transferring bone marrow (BM) and purified splenic T cells from C57BL/6J mice into irradiated C3-SW.H2b mice (BM+T). Control groups received BM only. Mice were scored clinically across the post-transplantation period. MGD severity was categorized using the degree of atrophy on harvested lids. Immune disease was analyzed using flow cytometry of tissues along with fluorescent tracking of BM cells onto the ocular surface. In humans, parameters from 57 patients with ocular GVHD presenting to the Duke Eye Center were retrospectively reviewed. MGD was categorized using the degree of atrophy on meibographs. Immune analysis was done using high-parameter flow cytometry on tear samples.

RESULTS

Compared with BM only, BM+T mice had higher systemic disease scores that correlated with tear fluid loss and eyelid edema. BM+T had higher immune cell infiltration in the ocular tissues and higher CD4+-cell cytokine expression in draining lymph nodes. BM+T mice with worse MGD scores had significantly worse corneal staining. In patients with ocular GVHD, 96% had other organs affected. Patients with ocular GVHD had abnormal parameters on dry eye testing, high matrix metalloproteinase-9 positivity (92%), and abundance of immune cells in tear samples. Ocular surface disease signs were worse in patients with higher MGD severity scores.

CONCLUSIONS

Ocular GVHD is driven by a systemic, T-cell-dependent process that causes meibomian gland damage and induces a robust form of ocular surface disease that correlates with MGD severity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Left Ventricular Hypertrophy and Ventricular Tachyarrhythmia: The Role of Biomarkers

Left ventricular hypertrophy (LVH) refers to a complex rebuilding of the left ventricle that can gradually lead to serious complications-heart failure and life-threatening ventricular arrhythmias. LVH is defined as an increase in the size of the left ventricle (i.e., anatomically), therefore the basic diagnosis detecting the increase in the LV size is the domain of imaging methods such as echocardiography and cardiac magnetic resonance. However, to evaluate the functional status indicating the gradual deterioration of the left ventricular myocardium, additional methods are available approaching the complex process of hypertrophic remodeling. The novel molecular and genetic biomarkers provide insights on the underlying processes, representing a potential basis for targeted therapy. This review summarizes the spectrum of the main biomarkers employed in the LVH valuation.

Matrix Metalloproteinases in Cardioembolic Stroke: From Background to Complications

Matrix metalloproteinases (MMPs) are endopeptidases participating in physiological processes of the brain, maintaining the blood-brain barrier integrity and playing a critical role in cerebral ischemia. In the acute phase of stroke activity, the expression of MMPs increase and is associated with adverse effects, but in the post-stroke phase, MMPs contribute to the process of healing by remodeling tissue lesions. The imbalance between MMPs and their inhibitors results in excessive fibrosis associated with the enhanced risk of atrial fibrillation (AF), which is the main cause of cardioembolic strokes. MMPs activity disturbances were observed in the development of hypertension, diabetes, heart failure and vascular disease enclosed in CHA₂DS₂VASc score, the scale commonly used to evaluate the risk of thromboembolic complications risk in AF patients. MMPs involved in hemorrhagic complications of stroke and activated by reperfusion therapy may also worsen the stroke outcome. In the present review, we briefly summarize the role of MMPs in the ischemic stroke with particular consideration of the cardioembolic stroke and its complications. Moreover, we discuss the genetic background, regulation pathways, clinical risk factors and impact of MMPs on the clinical outcome.

Cardiac-Specific Expression of Cre Recombinase Leads to Age-Related Cardiac Dysfunction Associated with Tumor-like Growth of Atrial Cardiomyocyte and Ventricular Fibrosis and Ferroptosis

Transgenic expression of Cre recombinase driven by a specific promoter is normally used to conditionally knockout a gene in a tissue- or cell-type-specific manner. In αMHC-Cre transgenic mouse model, expression of Cre recombinase is controlled by the myocardial-specific α-myosin heavy chain (αMHC) promoter, which is commonly used to edit myocardial-specific genes. Toxic effects of Cre expression have been reported, including intro-chromosome rearrangements, micronuclei formation and other forms of DNA damage, and cardiomyopathy was observed in cardiac-specific Cre transgenic mice. However, mechanisms associated with Cardiotoxicity of Cre remain poorly understood. In our study, our data unveiled that αMHC-Cre mice developed arrhythmias and died after six months progressively, and none of them survived more than one year. Histopathological examination showed that αMHC-Cre mice had aberrant proliferation of tumor-like tissue in the atrial chamber extended from and vacuolation of ventricular myocytes. Furthermore, the αMHC-Cre mice developed severe cardiac interstitial and perivascular fibrosis, accompanied by significant increase of expression levels of MMP-2 and MMP-9 in the cardiac atrium and ventricular. Moreover, cardiac-specific expression of Cre led to disintegration of the intercalated disc, along with altered proteins expression of the disc and calcium-handling abnormality. Comprehensively, we identified that the ferroptosis signaling pathway is involved in heart failure caused by cardiac-specific expression of Cre, on which oxidative stress results in cytoplasmic vacuole accumulation of lipid peroxidation on the myocardial cell membrane. Taken together, these results revealed that cardiac-specific expression of Cre recombinase can lead to atrial mesenchymal tumor-like growth in the mice, which causes cardiac dysfunction, including cardiac fibrosis, reduction of the intercalated disc and cardiomyocytes ferroptosis at the age older than six months in mice. Our study suggests that αMHC-Cre mouse models are effective in young mice, but not in old mice. Researchers need to be particularly careful when using αMHC-Cre mouse model to interpret those phenotypic impacts of gene responses. As the Cre-associated cardiac pathology matched mostly to that of the patients, the model could also be employed for investigating age-related cardiac dysfunction.

Germline gain-of-function MMP11 variant results in an aggressive form of colorectal cancer

Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.

Metalloproteinases in Cardiac Surgery: A Systematic Review

The role of matrix metalloproteinases (MMPs) in routine cardiac operations including cardiopulmonary bypass (CPB) is still poorly explored. The purpose of this systematic review was to thoroughly summarize and discuss the existing knowledge of the MMP profile in cardiac surgery. All studies meeting the inclusion criteria (i.e., those reporting detailed data about MMP release during and after CPB) were selected after screening the literature published between July 1975 and August 2022. Fifteen trials that enrolled a total of 431 participants were included. MMP levels were found to be significantly correlated with CPB in all included studies. The gelatinases MMP-2 and MMP-9 were highly released in cardiac surgery with CPB. MMP-9 levels were found to be increased after CPB start and during the duration of CPB. Particularly, it is overexpressed both in the myocardial tissue and circulating in the bloodstream. Also, MMP-2 levels increased after CPB both in plasma and in myocardial tissue. MMP-7, MMP-8, and MMP-13 levels increased after CPB start and remained elevated up to 6 h later. Increased levels of MMPs were associated with adverse post-operative outcomes. Conversely, TIMP-1 decreased with CPB. Mechanical and pharmacological strategies were applied in two studies to analyze their effect on the inflammatory response to cardiac surgery and CPB and on postoperative outcomes. New targeted MMP inhibitor therapies could protect against systemic inflammatory response syndrome after CPB and should be the subject of future large prospective multicenter randomized clinical trials.

Post-ischemic cardioprotective potential of exogenous ubiquitin in myocardial remodeling late after ischemia/reperfusion injury

AIMS

Pretreatment with ubiquitin (UB) associates with preservation of heart function 3 days post-ischemia/reperfusion (I/R) injury. This study investigated the cardioprotective potential of exogenous UB late after myocardial I/R injury. To enhance the clinical relevance, UB treatment was started at the time of reperfusion and continued for 28 days post-I/R.

MAIN METHODS

Mice underwent ligation of the left anterior descending coronary artery for 45 min. At the time of reperfusion, mice were treated with UB or saline which was continued until 28 days post-I/R. Heart function was measured at 3, 7, 14 and 28 days post-I/R using echocardiography. Biochemical parameters of the heart and serum cytokines/chemokines levels were measured 28 days post-I/R.

KEY FINDINGS

I/R decreased heart function and induced LV dilation at all time points post-I/R. However, I/R + UB exhibited improved heart function throughout the observation period, while LV dilation was lower in I/R + UB group at 3, 14 and 28 days post-I/R. I/R-mediated increase in myocardial fibrosis, hypertrophy and apoptosis were significantly lower in I/R + UB vs. I/R. Collagen-1α1 and MMP-2 expression was lower, while MMP-9 and TIMP-2 expression was higher in I/R + UB vs. I/R. MYH-7B (hypertrophy marker) expression was lower in I/R + UB vs. I/R. GSK3β activation was lower (vs. Sham), while activation of ERK1/2 (vs. I/R) and AKT (vs. Sham) was higher in I/R + UB. Serum levels of IL-6, G-CSF and IL-2 were lower in I/R + UB vs. I/R.

SIGNIFICANCE

Post-ischemic UB treatment improves heart function, and associates with decreased myocardial fibrosis, apoptosis, hypertrophy and serum cytokine/chemokine levels.

Meta-Analysis of Extracellular Matrix Dynamics after Myocardial Infarction Using RNA-Sequencing Transcriptomic Database

Extracellular matrix (ECM) changes after myocardial infarction (MI) need precise regulation, and next-generation sequencing technologies provide omics data that can be used in this context. We performed a meta-analysis using RNA-sequencing transcriptomic datasets to identify genes involved in post-MI ECM turnover. Eight studies available in Gene Expression Omnibus were selected following the inclusion criteria. We compare RNA-sequencing data from 92 mice submitted to permanent coronary ligation or sham, identifying differentially expressed genes (p-value < 0.05 and Log2FoldChange ≥ 2). Functional enrichment analysis was performed based on Gene Ontology biological processes (BPs). BPs implicated in response to extracellular stimulus, regulation of ECM organization, and ECM disassembly were detected soon after ischemia onset. ECM disassembly occurred between days one to seven post-MI, compared with ECM assembly from day seven onwards. We identified altered mRNA expression of 19 matrix metalloproteinases and four tissue inhibitors of metalloproteinases at post-infarcted ECM remodeling and altered transcriptomic expression of 42 genes encoding 26 collagen subunits at the fibrotic stage. To our knowledge, this is the first meta-analysis using RNA-sequencing datasets to evaluate post-infarcted cardiac interstitium healing, revealing previously unknown mechanisms and molecules actively implicated in ECM remodeling post-MI, which warrant further validation.

Modulation of Mitochondrial Bioenergetics by Polydopamine Nanoparticles in Human iPSC-Derived Cardiomyocytes

Myocardial infarction (MI) leads to the formation of an akinetic scar on the heart muscle causing impairment in cardiac contractility and conductance, leading to cardiac remodeling and heart failure (HF). The current pharmacological approaches for attenuating MI are limited and often come with long-term adverse effects. Therefore, there is an urgent need to develop novel multimodal therapeutics capable of modulating cardiac activity without causing any major adverse effects. In the current study, we have demonstrated the applicability of polydopamine nanoparticles (PDA-NPs) as a bioactive agent that can enhance the contractility and beat propagation of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Treatment of hiPSC-CMs with PDA-NPs demonstrated accumulation of the latter into mitochondria and significantly enhanced time-dependent adenosine triphosphate (ATP) production in these cells, indicating improved mitochondrial bioenergetics. Furthermore, the effect of PDA-NPs on hiPSC-CM activity was evaluated by measuring calcium transients. Treatment with PDA-NPs increased the calcium cycling in hiPSC-CMs in a temporal manner. Our results demonstrated a significant reduction in peak amplitude, transient duration, time to peak, and transient decay time in the PDA-NPs-treated hiPSC-CMs as compared to untreated hiPSC-CMs. Additionally, treatment of isolated perfused rat heart ex vivo with PDA-NPs demonstrated cardiotonic effects on the heart and significantly improved the hemodynamic function, suggesting its potential for enhancing whole heart contractility. Lastly, the gene expression analysis data revealed that PDA-NPs significantly upregulated cardiac-specific genes (ACADM, MYL2, MYC, HCN1, MYL7, GJA5, and PDHA1) demonstrating the ability to modulate genetic expression of cardiomyocytes. Taken together, these findings suggest PDA-NPs capability as a versatile nanomaterial with potential uses in next-generation cardiovascular applications.

Follistatin-like 1 and its paralogs in heart development and cardiovascular disease

Cardiovascular diseases (CVDs) are a group of disorders affecting the heart and blood vessels and a leading cause of death worldwide. Thus, there is a need to identify new cardiokines that may protect the heart from damage as reported in GBD 2017 Causes of Death Collaborators (2018) (The Lancet 392:1736-1788). Follistatin-like 1 (FSTL1) is a cardiokine that is highly expressed in the heart and released to the serum after cardiac injury where it is associated with CVD and predicts poor outcome. The action of FSTL1 likely depends not only on the tissue source but also post-translation modifications that are target tissue- and cell-specific. Animal studies examining the effect of FSTL1 in various models of heart disease have exploded over the past 15 years and primarily report a protective effect spanning from inhibiting inflammation via transforming growth factor, preventing remodeling and fibrosis to promoting angiogenesis and hypertrophy. A better understanding of FSTL1 and its homologs is needed to determine whether this protein could be a useful novel biomarker to predict poor outcome and death and whether it has therapeutic potential. The aim of this review is to provide a comprehensive description of the literature for this family of proteins in order to better understand their role in normal physiology and CVD.

Adeno-associated virus 9 vector-mediated cardiac-selective expression of human secretory leukocyte protease inhibitor attenuates myocardial ischemia/reperfusion injury

Protease enzymes contribute to the initiation of cardiac remodeling and heart failure after myocardial ischemic/reperfusion (I/R) injury. Protease inhibitors attenuate protease activity and limit left ventricular dysfunction and remodeling. Previous studies showed the cardioprotective effect of secretory leukocyte protease inhibitor (SLPI) against I/R injury. However, overexpression of SLPI gene in cardiovascular diseases has only been investigated in an in vitro experiment. Here, cardiac-selective expression of the human secretory leukocyte protease inhibitor (hSLPI) gene and its effect on I/R injury were investigated. Adeno-associated virus (AAV) serotype 9 carrying hSLPI under the control of cardiac-selective expression promoter (cardiac troponin, cTn) was intravenously administered to Sprague–Dawley rats for 4 weeks prior to coronary artery ligation. The results showed that myocardial-selective expression of hSLPI significantly reduced infarct size, cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and myoglobin levels that all served to improve cardiac function. Moreover, overexpression of hSLPI showed a reduction in inflammatory cytokines, oxidatively modified protein carbonyl (PC) content, ischemia-modified albumin (IMA), and necrosis and cardiac tissue degeneration. In conclusion, this is the first study to demonstrate cardiac-selective gene delivery of hSLPI providing cardioprotection against myocardial I/R injury in an in vivo model.

Protective Effects of Circulating TIMP3 on Coronary Artery Disease and Myocardial Infarction: A Mendelian Randomization Study

Tissue inhibitor of metalloproteinase 3 (TIMP3) is a protease with high expression levels in the heart and plays an essential role in extracellular matrix turnover by maintaining equilibrium with matrix metalloproteinases. Considerable data in experimental models have demonstrated a protective role of TIMP3 in coronary artery disease (CAD) and myocardial infarction (MI). However, causality remains unexplored in population studies. Here, we sought to decipher the potential causality between TIMP3 and CAD/MI using the Mendelian randomization (MR) method. We extracted summary−level datasets for TIMP3 and CAD/MI from the genome−wide association studies performed in the KORA study and CARDIoGRAMplusC4D consortium, respectively. Seven independent SNPs were obtained as instrumental variables for TIMP3. The MR analyses were replicated using FinnGen datasets, and the main results were combined in meta−analyses. Elevated genetically predicted serum TIMP3 levels were causally associated with a lower risk of CAD [odds ratio (OR), 0.97; 95% confidence interval (CI), 0.95, 0.98; p = 5.29 × 10⁻⁵] and MI (OR, 0.96; 95% CI, 0.95, 0.98; p = 3.85 × 10⁻⁵). The association patterns persisted in the meta−analyses combining the different datasets (CAD: OR, 0.97; 95% CI, 0.96, 0.99; p = 4.37 × 10⁻⁵; MI: OR, 0.97; 95% CI, 0.96, 0.99; p = 9.96 × 10⁻⁵) and was broadly consistent across a set of complementary analyses. Evidence of heterogeneity and horizontal pleiotropy was limited for all associations considered. In conclusion, this MR study supports inverse causal associations between serum TIMP3 and the risk of CAD and MI. Strategies for raising TIMP3 levels may offer new avenues for the prevention strategies of atherosclerotic cardiovascular diseases.