Increased levels of laminin and collagen type VI may reflect early remodelling in patients with acute myocardial infarction

The Current State of Extracellular Matrix Therapy for Ischemic Heart Disease

The extracellular matrix (ECM) is a three-dimensional, acellular network of diverse structural and nonstructural proteins embedded within a gel-like ground substance composed of glycosaminoglycans and proteoglycans. The ECM serves numerous roles that vary according to the tissue in which it is situated. In the myocardium, the ECM acts as a collagen-based scaffold that mediates the transmission of contractile signals, provides means for paracrine signaling, and maintains nutritional and immunologic homeostasis. Given this spectrum, it is unsurprising that both the composition and role of the ECM has been found to be modulated in the context of cardiac pathology. Myocardial infarction (MI) provides a familiar example of this; the ECM changes in a way that is characteristic of the progressive phases of post-infarction healing. In recent years, this involvement in infarct pathophysiology has prompted a search for therapeutic targets: if ECM components facilitate healing, then their manipulation may accelerate recovery, or even reverse pre-existing damage. This possibility has been the subject of numerous efforts involving the integration of ECM-based therapies, either derived directly from biologic sources or bioengineered sources, into models of myocardial disease. In this paper, we provide a thorough review of the published literature on the use of the ECM as a novel therapy for ischemic heart disease, with a focus on biologically derived models, of both the whole ECM and the components thereof.

Correlation between serum laminin levels and prognosis of acute myocardial infarction

Background

Acute myocardial infarction (AMI) is a critical cardiovascular disease (CVD). Laminin (LN) is involved in the process of myocardial fibrosis and ventricular remodeling observed in AMI; however, there are currently no studies on the correlation between LN and AMI prognosis.

Purpose

To explore the predictive value of serum LN levels for major adverse cardiovascular events (MACE) in patients, 6 months after an acute myocardial infarction.

Methods

A total of 202 AMI patients who were hospitalized in the Department of Cardiology of the Second Affiliated Hospital of Nantong University between December 2019 and December 2020 were included. The observation endpoint was the occurrence of MACE. Univariate and multivariate logistic analyses were used to evaluate the relationships between the variables and endpoint. The predictive value of LN for MACE in AMI patients was assessed using receiver operating characteristic (ROC) analysis.

Results

A total of 47 patients developed MACE. Univariate logistic analysis showed that smoking, emergency percutaneous coronary intervention (EPCI), age, cardiac troponin I (c-TNI) levels, N-terminal prohormone brain natriuretic peptide (NT-proBNP) levels, and LN levels were associated with the occurrence of MACE (p < 0.05). Multivariate logistic analysis showed that LN was an independent predictor of MACE (odds ratio [OR] = 1.021, 95%CI: 1.014–1.032, p < 0.001). According to the ROC curve, LN can be used as an effective predictor of MACE (AUC = 0.856, 95%CI: 0.794–0.918, p < 0.001). According to the cutoff value, LN>58.80 ng/ml (sensitivity = 83.00%, specificity = 76.80%) or LN>74.15 ng/ml (sensitivity = 76.6%, specificity = 83.2%) indicate a poor prognosis for AMI. Different cut-off values are selected according to the need for higher sensitivity or specificity in clinical applications.

Conclusions

LN may be a predictor of MACE following AMI in patients and could be utilized as a novel substitute marker for the prevention and treatment of AMI.

Changes in Laminin in Acute Heart Failure

Laminin is a major component of the basement membrane of cardiomyocytes and has been found at a high level in patients with heart failure. However, detailed information on the relationship between disease management and progression in patients with acute heart failure (AHF) remains lacking. We focused on the levels of laminin (LN) before and after admission to the hospital in AHF patients. One hundred twelve AHF patients who were hospitalized in the Affiliated Hospital 2 of Nantong University from January 2020 to February 2021 were selected as the main subjects of the study. The control group consisted of 137 hospitalized patients in New York Heart Association (NYHA) classes I-II during the same time period. Serum laminin levels were measured at baseline in all patients. Besides, laminin levels of AHF patients were measured again 1 week after admission. The serum laminin levels at admission were significantly higher in AHF patients than those in the patients of NYHA classes I-II [73.79 (41.04, 129.75) ng/mL versus 27.98 (20.75, 37.49) ng/mL, respectively, P < 0.001]. After 1 week of treatment, laminin levels in AHF patients were 41.56 (27.92, 78.67) ng/mL, which was significantly lower than before treatment (Z = -6.357, P < 0.001). Bivariate linear correlation analysis showed that LN was associated with NT-proBNP both in the acute phase and after treatment. Laminin levels were significantly higher in AHF patients who had atrial fibrillation (AF) than in those without AF. As a result, we speculated that laminin reflected improved heart function and the occurrence of myocardial fibrosis.

Interstitial changes after reperfused myocardial infarction in swine: morphometric and genetic analysis

Background

Following myocardial infarction (MI), we aimed to characterize morphometric and genetic changes in extracellular matrix (ECM) components from ischemia onset until late phases after coronary reperfusion in necrotic and salvaged myocardium.

Results

Swine were divided into one control (n = 5) and three MI groups: 90-min of ischemia without reperfusion, or followed by 1-week or 1-month reperfusion (n = 5 per group). In samples from the necrotic and salvaged areas, ECM components were morphometrically quantified and mRNA levels of factors involved in ECM remodeling were evaluated. After 90-min of ischemia, fibronectin, laminin, and elastic fibers content as well as upregulated mRNA expression of tissue inhibitors of metalloproteinases (TIMP)1, TIMP2, TIMP3 and connective tissue growth factor increased in the necrotic and salvaged myocardium. In both reperfused MI groups, collagen-I, collagen-III, elastic fibers, glycosaminoglycans, laminin, and fibronectin levels heightened in the necrotic but not the salvaged myocardium. Moreover, mRNA expression of TIMP1, TIMP2 and TIMP3, as well as metalloproteinase-2 and metalloproteinase-9 heightened in the necrotic but not in the salvaged myocardium.

Conclusions

Matrix remodeling starts after ischemia onset in both necrotic and salvaged myocardium. Even if ECM composition from the salvaged myocardium was altered after severe ischemia, ECM makes a full recovery to normal composition after reperfusion. Therefore, rapid coronary reperfusion is essential not only to save cardiomyocytes but also to preserve matrix, thus avoiding impaired left ventricular remodeling.

Current advances in the study of diabetic cardiomyopathy: From clinicopathological features to molecular therapeutics (Review)

The incidence of diabetes mellitus has become a major public health concern due to lifestyle alterations. Moreover, the complications associated with diabetes mellitus deeply influence the quality of life of patients. Diabetic cardiomyopathy (DC) is a type of diabetes mellitus complication characterized by functional and structural damage in the myocardium but not accompanied by coronary arterial disease. Currently, diagnosing and preventing DC is still a challenge for physicians due to its atypical symptoms. For this reason, it is necessary to summarize the current knowledge on DC, especially in regards to the underlying molecular mechanisms toward the goal of developing useful diagnostic approaches and effective drugs based on these mechanisms. There exist several review articles which have focused on these points, but there still remains a lot to learn from published studies. In this review, the features, diagnosis and molecular mechanisms of DC are reviewed. Furthermore, potential therapeutic and prophylactic drugs are discussed.

Unravelling the effects of mechanical physiological conditioning on cardiac adipose tissue-derived progenitor cells in vitro and in silico

Mechanical conditioning is incompletely characterized for stimulating therapeutic cells within the physiological range. We sought to unravel the mechanism of action underlying mechanical conditioning of adipose tissue-derived progenitor cells (ATDPCs), both in vitro and in silico. Cardiac ATDPCs, grown on 3 different patterned surfaces, were mechanically stretched for 7 days at 1 Hz. A custom-designed, magnet-based, mechanical stimulator device was developed to apply ~10% mechanical stretching to monolayer cell cultures. Gene and protein analyses were performed for each cell type and condition. Cell supernatants were also collected to analyze secreted proteins and construct an artificial neural network. Gene and protein modulations were different for each surface pattern. After mechanostimulation, cardiac ATDPCs increased the expression of structural genes and there was a rising trend on cardiac transcription factors. Finally, secretome analyses revealed upregulation of proteins associated with both myocardial infarction and cardiac regeneration, such as regulators of the immune response, angiogenesis or cell adhesion. To conclude, mechanical conditioning of cardiac ATDPCs enhanced the expression of early and late cardiac genes in vitro. Additionally, in silico analyses of secreted proteins showed that mechanical stimulation of cardiac ATDPCs was highly associated with myocardial infarction and repair.

Diabetic cardiomyopathy: where we are and where we are going

The global burden of diabetes mellitus and its related complications are currently increasing. Diabetes mellitus affects the heart through various mechanisms including microvascular impairment, metabolic disturbance, subcellular component abnormalities, cardiac autonomic dysfunction, and a maladaptive immune response. Eventually, diabetes mellitus can cause functional and structural changes in the myocardium without coronary artery disease, a disorder known as diabetic cardiomyopathy (DCM). There are many diagnostic tools and management options for DCM, although it is difficult to detect its development and effectively prevent its progression. In this review, we summarize the current research regarding the pathophysiology and pathogenesis of DCM. Moreover, we discuss emerging diagnostic evaluation methods and treatment strategies for DCM, which may help our understanding of its underlying mechanisms and facilitate the identification of possible new therapeutic targets.

Temporal cardiac remodeling post-myocardial infarction: dynamics and prognostic implications in personalized medicine

Despite dramatic improvements in short-term mortality rates following myocardial infarction (MI), long-term survival for MI patients who progress to heart failure remains poor. MI occurs when the left ventricle (LV) is deprived of oxygen for a sufficient period of time to induce irreversible necrosis of the myocardium. The LV response to MI involves significant tissue, cellular, and molecular level modifications, as well as substantial hemodynamic changes that feedback negatively to amplify the response. Inflammation to remove necrotic myocytes and fibroblast activation to form a scar are key wound healing responses that are highly variable across individuals. Few biomarkers of early remodeling stages are currently clinically adopted. The discovery of underlying pathophysiological mechanisms and associated novel biomarkers has the potential of improving prognostic capability and therapeutic monitoring. Combining these biomarkers with other prominent ones could constitute a powerful diagnostic and prognostic tool that directly reflects the pathophysiological remodeling of the LV. Understanding temporal remodeling at the tissue, cellular, and molecular level and its link to a well-defined set of biomarkers at early stages post-MI is a prerequisite for improving personalized care and devising more successful therapeutic interventions. Here we summarize the integral mechanisms that occur during early cardiac remodeling in the post-MI setting and highlight the most prominent biomarkers for assessing disease progression.

Myofibroblasts and the extracellular matrix network in post-myocardial infarction cardiac remodeling

The cardiac extracellular matrix (ECM) fills the space between cells, supports tissue organization, and transduces mechanical, chemical, and biological signals to regulate homeostasis of the left ventricle (LV). Following myocardial infarction (MI), a multitude of ECM proteins are synthesized to replace myocyte loss and form a reparative scar. Activated fibroblasts (myofibroblasts) are the primary source of ECM proteins, thus playing a key role in cardiac repair. A balanced turnover of ECM through regulation of synthesis by myofibroblasts and degradation by matrix metalloproteinases (MMPs) is critical for proper scar formation. In this review, we summarize the current literature on the roles of myofibroblasts, MMPs, and ECM proteins in MI-induced LV remodeling. In addition, we discuss future research directions that are needed to further elucidate the molecular mechanisms of ECM actions to optimize cardiac repair.

Extracellular matrix remodeling following myocardial infarction influences the therapeutic potential of mesenchymal stem cells

INTRODUCTION

Although stem cell therapy is a promising treatment for myocardial infarction, the minimal functional improvements observed clinically limit its widespread application. A need exists to maximize the therapeutic potential of these stem cells by first understanding what factors within the infarct microenvironment affect their ability to regenerate the necrotic tissue. In this study, we assessed both differentiation capacity and paracrine signaling as a function of extracellular matrix remodeling after myocardial infarction.

METHODS

Mechanical and compositional changes to the decellularized infarcted myocardium were characterized to understand how the extracellular environment, specifically, was altered as a function of time after coronary artery ligation in Sprague-Dawley rats. These alterations were first modeled in a polyacrylamide gel system to understand how the variables of composition and stiffness drive mesenchymal stem cell differentiation towards a cardiac lineage. Finally, the paracrine secretome was characterized as a function of matrix remodeling through gene and protein expression and conditioned media studies.

RESULTS

The decellularized infarct tissue revealed significant alterations in both the mechanical and compositional properties of the ECM with remodeling following infarction. This altered microenvironment dynamically regulates the potential for early cardiac differentiation. Whereas Nkx2.5 expression is limited in the presence of chronic remodeled matrix of increased stiffness, GATA4 expression is enhanced. In addition, the remodeled matrix promotes the expression of several proangiogenic, prosurvival, antifibrotic, and immunomodulatory growth factors. In particular, an increase in HGF and SDF1 expression and secretion by mesenchymal stem cells can rescue oxidatively stressed cardiomyocytes in vitro.

CONCLUSIONS

This study demonstrated that decellularization of diseased tissue allows for the exclusive analysis of the remodeled matrix and its ability to influence significantly the cellular phenotype. Characterization of cell fate as a function of myocardial remodeling following infarction is critical in developing the ideal strategy for cell implantation to maximize tissue regeneration and to ultimately reduce the prevalence and severity of heart failure.

Extracellular matrix and fibroblast communication following myocardial infarction

The extracellular matrix (ECM) provides structural support by serving as a scaffold for cells, and as such the ECM maintains normal tissue homeostasis and mediates the repair response following injury. In response to myocardial infarction (MI), ECM expression is generally upregulated in the left ventricle (LV), which regulates LV remodeling by modulating scar formation. The ECM directly affects scar formation by regulating growth factor release and cell adhesion and indirectly affects scar formation by regulating the inflammatory, angiogenic, and fibroblast responses. This review summarizes the current literature on ECM expression patterns and fibroblast mechanisms in the myocardium, focusing on the ECM response to MI. In addition, we discuss future research areas that are needed to better understand the molecular mechanisms of ECM action, both in general and as a means to optimize infarct healing.

Neuronal p60TRP expression modulates cardiac capacity

Heart failure, including myocardial infarction, is the leading cause for death and the incidence of cardiovascular diseases is predicted to continue to rise worldwide. In the present study we investigated the whole heart proteome profile of transgenic p60-Transcription Regulator Protein (p60TRP) mice to gain an insight into the molecular events caused by the long-term effect of neural p60TRP over-expression on cardiac proteome changes and its potential implication for cardiovascular functions. Using an iTRAQ (isobaric tags for relative and absolute quantitation)-based proteomics research approach, we identified 1148 proteins, out of which 116 were found to be significantly altered in the heart of neural transgenic p60TRP mice. Based on the observed data, we conclude that in vivo neural over-expression of transgenic p60TRP with its neuroprotective therapeutic potential significantly affects cardiovascular capacities.

Quantitative N-linked glycoproteomics of myocardial ischemia and reperfusion injury reveals early remodeling in the extracellular environment

Extracellular and cell surface proteins are generally modified with N-linked glycans and glycopeptide enrichment is an attractive tool to analyze these proteins. The role of N-linked glycoproteins in cardiovascular disease, particularly ischemia and reperfusion injury, is poorly understood. Observation of glycopeptides by mass spectrometry is challenging due to the presence of abundant, nonglycosylated analytes, and robust methods for purification are essential. We employed digestion with multiple proteases to increase glycoproteome coverage coupled with parallel glycopeptide enrichments using hydrazide capture, titanium dioxide, and hydrophilic interaction liquid chromatography with and without an ion-pairing agent. Glycosylated peptides were treated with PNGase F and analyzed by liquid chromatography-MS/MS. This allowed the identification of 1556 nonredundant N-linked glycosylation sites, representing 972 protein groups from ex vivo rat left ventricular myocardium. False positive "glycosylations" were observed on 44 peptides containing a deamidated Asn-Asp in the N-linked sequon by analysis of samples without PNGase F treatment. We used quantitation via isobaric tags for relative and absolute quantitation (iTRAQ) and validation with dimethyl labeling to analyze changes in glycoproteins from tissue following prolonged ischemia and reperfusion (40 mins ischemia and 20 mins reperfusion) indicative of myocardial infarction. The iTRAQ approach revealed 80 of 437 glycopeptides with altered abundance, while dimethyl labeling confirmed 46 of these and revealed an additional 62 significant changes. These were mainly from predicted extracellular matrix and basement membrane proteins that are implicated in cardiac remodeling. Analysis of N-glycans released from myocardial proteins suggest that the observed changes were not due to significant alterations in N-glycan structures. Altered proteins included the collagen-laminin-integrin complexes and collagen assembly enzymes, cadherins, mast cell proteases, proliferation-associated secreted protein acidic and rich in cysteine, and microfibril-associated proteins. The data suggest that cardiac remodeling is initiated earlier during reperfusion than previously hypothesized.