Influence of epicardial adipose tissue inflammation and adipocyte size on postoperative atrial fibrillation in patients after cardiovascular surgery.

Epicardial adipose tissue (EAT) is an active endocrine organ that is closely associated with occurrence of atrial fibrillation (AF). However, the role of EAT in the development of postoperative AF (POAF) remains unclear. We aimed to investigate the association between EAT profile and POAF occurrence in patients who underwent cardiovascular surgery. We obtained EAT samples from 53 patients to evaluate gene expression, histological changes, mitochondrial oxidative phosphorylation (OXPHOS) capacity in the EAT, and protein secretion in EAT-conditioned medium. EAT volume was measured using computed tomography scan. Eighteen patients (34%) experienced POAF within 7 days after surgery. Although no significant difference was observed in EAT profile between patients with and without POAF, logistic regression analysis identified that the mRNA expression levels of tumor necrosis factor-alpha (TNF-α) were positively correlated and adipocyte size in the EAT was inversely correlated with onset of POAF, respectively. Mitochondrial OXPHOS capacity in the EAT was not associated with POAF occurrence; however, it showed an inverse correlation with adipocyte size and a positive correlation with adiponectin secretion. In conclusion, changes in the secretory profile and adipocyte morphology of the EAT, which represent qualitative aspects of the adipose tissue, were present before the onset of AF.

The zebrafish heart harbors a thermogenic beige fat depot analog of human epicardial adipose tissue.

Epicardial adipose tissue (eAT) is a metabolically active fat depot that has been associated with a wide array of cardiac homeostatic functions and cardiometabolic diseases. A full understanding of its diverse physiological and pathological roles is hindered by the dearth of animal models. Here, we show, in the heart of an ectothermic teleost, the zebrafish, the existence of a fat depot localized underneath the epicardium, originating from the epicardium and exhibiting the molecular signature of beige adipocytes. Moreover, a subset of adipocytes within this cardiac fat tissue exhibits primitive thermogenic potential. Transcriptomic profiling and cross-species analysis revealed elevated glycolytic and cardiac homeostatic gene expression with downregulated obesity and inflammatory hallmarks in the teleost eAT compared to that of lean aged humans. Our findings unveil epicardium-derived beige fat in the heart of an ectotherm considered to possess solely white adipocytes for energy storage and identify pathways that may underlie age-driven remodeling of human eAT.

Pericardial delta like non-canonical NOTCH ligand 1 (Dlk1) augments fibrosis in the heart through epithelial to mesenchymal transition.

BACKGROUND: Heart failure due to myocardial infarction (MI) involves fibrosis driven by epicardium-derived cells (EPDCs) and cardiac fibroblasts, but strategies to inhibit and provide cardio-protection remains poor. The imprinted gene, non-canonical NOTCH ligand 1 (Dlk1), has previously been shown to mediate fibrosis in the skin, lung and liver, but very little is known on its effect in the heart. METHODS: Herein, human pericardial fluid/plasma and tissue biopsies were assessed for DLK1, whereas the spatiotemporal expression of Dlk1 was determined in mouse hearts. The Dlk1 heart phenotype in normal and MI hearts was assessed in transgenic mice either lacking or overexpressing Dlk1. Finally, in/ex vivo cell studies provided knowledge on the molecular mechanism. RESULTS: Dlk1 was demonstrated in non-myocytes of the developing human myocardium but exhibited a restricted pericardial expression in adulthood. Soluble DLK1 was twofold higher in pericardial fluid (median 45.7 [34.7 (IQR)) µg/L] from cardiovascular patients (n = 127) than in plasma (median 26.1 µg/L [11.1 (IQR)]. The spatial and temporal expression pattern of Dlk1 was recapitulated in mouse and rat hearts. Similar to humans lacking Dlk1, adult Dlk1-/- mice exhibited a relatively mild developmental, although consistent cardiac phenotype with some abnormalities in heart size, shape, thorax orientation and non-myocyte number, but were functionally normal. However, after MI, scar size was substantially reduced in Dlk1-/- hearts as compared with Dlk1+/+ littermates. In line, high levels of Dlk1 in transgenic mice Dlk1fl/fl xWT1GFPCre and Dlk1fl/fl xαMHCCre/+Tam increased scar size following MI. Further mechanistic and cellular insight demonstrated that pericardial Dlk1 mediates cardiac fibrosis through epithelial to mesenchymal transition (EMT) of the EPDC lineage by maintaining Integrin ß8 (Itgb8), a major activator of transforming growth factor ß and EMT. CONCLUSIONS: Our results suggest that pericardial Dlk1 embraces a, so far, unnoticed role in the heart augmenting cardiac fibrosis through EMT. Monitoring DLK1 levels as well as targeting pericardial DLK1 may thus offer new venues for cardio-protection.

Investigation of anti-adhesion ability of 8-arm PEGNHS-modified porcine pericardium.

In post-adhesion surgery, there is a clinical need for anti-adhesion membranes specifically designed for the liver, given the limited efficacy of current commercial products. To address this demand, we present a membrane suitable for liver surgery applications, fabricated through the modification of decellularized porcine pericardium with 20 KDa hexaglycerol octa (succinimidyloxyglutaryl) polyoxyethylene (8-arm PEGNHS). We also developed an optimized modification procedure to produce a high-performance anti-adhesion barrier. The modified membrane significantly inhibited fibroblast cell adherence while maintaining minimal levels of inflammation. By optimizing the modification ratio, we successfully controlled post-adhesion formation. Notably, the 8-arm PEG-modified pericardium with a molar ratio of 5 exhibited the ability to effectively prevent post-adhesion formation on the liver compared to both the control and Seprafilm®, with a low adhesion score of 0.5 out of 3.0. Histological analysis further confirmed its potential for easy separation. Furthermore, the membrane demonstrated regenerative capabilities, as evidenced by the proliferation of mesothelial cells on its surface, endowing anti-adhesion properties between the abdominal wall and liver. These findings highlight the membrane's potential as a reliable barrier for repeated liver resection procedures that require the removal of the membrane multiple times.

Off-Target Effects of P2Y12 Receptor Inhibitors: Focus on Early Myocardial Fibrosis Modulation.

Several studies have demonstrated that, beyond their antithrombotic effects, P2Y12 receptor inhibitors may provide additional off-target effects through different mechanisms. These effects range from the preservation of endothelial barrier function to the modulation of inflammation or stabilization of atherosclerotic plaques, with an impact on different cell types, including endothelial and immune cells. Many P2Y12 inhibitors have been developed, from ticlopidine, the first thienopyridine, to the more potent non-thienopyridine derivatives such as ticagrelor which may promote cardioprotective effects following myocardial infarction (MI) by inhibiting adenosine reuptake through sodium-independent equilibrative nucleoside transporter 1 (ENT1). Adenosine may affect different molecular pathways involved in cardiac fibrosis, such as the Wnt (wingless-type)/beta (ß)-catenin signaling. An early pro-fibrotic response of the epicardium and activation of cardiac fibroblasts with the involvement of Wnt1 (wingless-type family member 1)/ß-catenin, are critically required for preserving cardiac function after acute ischemic cardiac injury. This review discusses molecular signaling pathways involved in cardiac fibrosis post MI, focusing on the Wnt/ß-catenin pathway, and the off-target effect of P2Y12 receptor inhibition. A potential role of ticagrelor was speculated in the early modulation of cardiac fibrosis, thanks to its off-target effect.

Atrial epicardial adipose tissue abundantly secretes myeloperoxidase and activates atrial fibroblasts in patients with atrial fibrillation.

BACKGROUND: Epicardial adipose tissue (EAT) secretome induces fibrosis. Fibrosis, primarily extracellular matrix (ECM) produced by fibroblasts, creates a substrate for atrial fibrillation (AF). Whether the EAT secretome from patients with AF activates human atrial fibroblasts and through which components, remains unexplored. RESEARCH AIMS: (a) To investigate if the EAT secretome from patients with versus without AF increases ECM production in atrial fibroblasts. (b) To identify profibrotic proteins and processes in the EAT secretome and EAT from patients with, who will develop (future onset), and without AF. METHODS: Atrial EAT was obtainded during thoracoscopic ablation (AF, n = 20), or open-heart surgery (future onset and non-AF, n = 35). ECM gene expression of human atrial fibroblasts exposed to the EAT secretome and the proteomes of EAT secretome and EAT were assessed in patients with and without AF. Myeloperoxidase and neutrophil extracellular traps (NETs) were assessed immunohistochemically in patients with paroxysmal, persistent, future onset, and those who remain free of AF (non-AF). RESULTS: The expression of COL1A1 and FN1 in fibroblasts exposed to secretome from patients with AF was 3.7 and 4.7 times higher than in patients without AF (p < 0.05). Myeloperoxidase was the most increased protein in the EAT secretome and EAT from patients with versus without AF (FC 18.07 and 21.57, p < 0.005), as was the gene-set neutrophil degranulation. Immunohistochemically, myeloperoxidase was highest in persistent (FC 13.3, p < 0.0001) and increased in future onset AF (FC 2.4, p = 0.02) versus non-AF. Myeloperoxidase aggregated subepicardially and around fibrofatty infiltrates. NETs were increased in patients with persistent versus non-AF (p = 0.03). CONCLUSION: In AF, the EAT secretome induces ECM gene expression in atrial fibroblasts and contains abundant myeloperoxidase. EAT myeloperoxidase was increased prior to AF onset, and both myeloperoxidase and NETs were highest in persistent AF, highlighting the role of EAT neutrophils in the pathophysiology of AF.

Expression of Ceramide-Metabolizing Enzymes in the Heart Adipose Tissue of Cardiovascular Disease Patients.

Here, we examined the expression of ceramide metabolism enzymes in the subcutaneous adipose tissue (SAT), epicardial adipose tissue (EAT) and perivascular adipose tissue (PVAT) of 30 patients with coronary artery disease (CAD) and 30 patients with valvular heart disease (VHD) by means of quantitative polymerase chain reaction and fluorescent Western blotting. The EAT of patients with CAD showed higher expression of the genes responsible for ceramide biosynthesis (SPTLC1, SPTLC2, CERS1, 5, 6, DEGS1, and SMPD1) and utilization (ASAH1, SGMS1). PVAT was characterized by higher mRNA levels of CERS3, CERS4, DEGS1, SMPD1, and ceramide utilization enzyme (SGMS2). In patients with VHD, there was a high CERS4, DEGS1, and SGMS2 expression in the EAT and CERS3 and CERS4 expression in the PVAT. Among patients with CAD, the expression of SPTLC1 in SAT and EAT, SPTLC2 in EAT, CERS2 in all studied AT, CERS4 and CERS5 in EAT, DEGS1 in SAT and EAT, ASAH1 in all studied AT, and SGMS1 in EAT was higher than in those with VHD. Protein levels of ceramide-metabolizing enzymes were consistent with gene expression trends. The obtained results indicate an activation of ceramide synthesis de novo and from sphingomyelin in cardiovascular disease, mainly in EAT, that contributes to the accumulation of ceramides in this location.

Single-cell analysis of human fetal epicardium reveals its cellular composition and identifies CRIP1 as a modulator of EMT.

The epicardium plays an essential role in cardiogenesis by providing cardiac cell types and paracrine cues to the developing myocardium. The human adult epicardium is quiescent, but recapitulation of developmental features may contribute to adult cardiac repair. The cell fate of epicardial cells is proposed to be determined by the developmental persistence of specific subpopulations. Reports on this epicardial heterogeneity have been inconsistent, and data regarding the human developing epicardium are scarce. Here we specifically isolated human fetal epicardium and used single-cell RNA sequencing to define its composition and to identify regulators of developmental processes. Few specific subpopulations were observed, but a clear distinction between epithelial and mesenchymal cells was present, resulting in novel population-specific markers. Additionally, we identified CRIP1 as a previously unknown regulator involved in epicardial epithelial-to-mesenchymal transition. Overall, our human fetal epicardial cell-enriched dataset provides an excellent platform to study the developing epicardium in great detail.

The role of epicardial adipose tissue dysfunction in cardiovascular diseases: an overview of pathophysiology, evaluation, and management.

In recent decades, the epicardial adipose tissue (EAT) has been at the forefront of scientific research because of its diverse role in the pathogenesis of cardiovascular diseases (CVDs). EAT lies between the myocardium and the visceral pericardium. The same microcirculation exists both in the epicardial fat and the myocardium. Under physiological circumstances, EAT serves as cushion and protects coronary arteries and myocardium from violent distortion and impact. In addition, EAT acts as an energy lipid source, thermoregulator, and endocrine organ. Under pathological conditions, EAT dysfunction promotes various CVDs progression in several ways. It seems that various secretions of the epicardial fat are responsible for myocardial metabolic disturbances and, finally, leads to CVDs. Therefore, EAT might be an early predictor of CVDs. Furthermore, different non-invasive imaging techniques have been proposed to identify and assess EAT as an important parameter to stratify the CVD risk. We also present the potential therapeutic possibilities aiming at modifying the function of EAT. This paper aims to provide overview of the potential role of EAT in CVDs, discuss different imaging techniques to assess EAT, and provide potential therapeutic options for EAT. Hence, EAT may represent as a potential predictor and a novel therapeutic target for management of CVDs in the future.

Single-cell analysis reveals an Angpt4-initiated EPDC-EC-CM cellular coordination cascade during heart regeneration.

Mammals exhibit limited heart regeneration ability, which can lead to heart failure after myocardial infarction. In contrast, zebrafish exhibit remarkable cardiac regeneration capacity. Several cell types and signaling pathways have been reported to participate in this process. However, a comprehensive analysis of how different cells and signals interact and coordinate to regulate cardiac regeneration is unavailable. We collected major cardiac cell types from zebrafish and performed high-precision single-cell transcriptome analyses during both development and post-injury regeneration. We revealed the cellular heterogeneity as well as the molecular progress of cardiomyocytes during these processes, and identified a subtype of atrial cardiomyocyte exhibiting a stem-like state which may transdifferentiate into ventricular cardiomyocytes during regeneration. Furthermore, we identified a regeneration-induced cell (RIC) population in the epicardium-derived cells (EPDC), and demonstrated Angiopoietin 4 (Angpt4) as a specific regulator of heart regeneration. angpt4 expression is specifically and transiently activated in RIC, which initiates a signaling cascade from EPDC to endocardium through the Tie2-MAPK pathway, and further induces activation of cathepsin K in cardiomyocytes through RA signaling. Loss of angpt4 leads to defects in scar tissue resolution and cardiomyocyte proliferation, while overexpression of angpt4 accelerates regeneration. Furthermore, we found that ANGPT4 could enhance proliferation of neonatal rat cardiomyocytes, and promote cardiac repair in mice after myocardial infarction, indicating that the function of Angpt4 is conserved in mammals. Our study provides a mechanistic understanding of heart regeneration at single-cell precision, identifies Angpt4 as a key regulator of cardiomyocyte proliferation and regeneration, and offers a novel therapeutic target for improved recovery after human heart injuries.

Epicardial Adipose Tissue in Myocardial Disease: From Physiology to Heart Failure Phenotypes.

Epicardial adipose tissue (EAT) is increasingly being recognized as a determinant of myocardial biology. The EAT-heart crosstalk suggests causal links between dysfunctional EAT and cardiomyocyte impairment. Obesity promotes EAT dysfunction and shifts in secreted adipokines which adversely affect cardiac metabolism, induce cardiomyocyte inflammation, redox imbalance and myocardial fibrosis. Thus, EAT determines cardiac phenotype via effects on cardiac energetics, contractility, diastolic function, and atrial conduction. Vice-versa the EAT is altered in heart failure (HF), and such phenotypic changes can be detected by noninvasive imaging or incorporated in Artificial Intelligence-enhanced tools to aid the diagnosis, subtyping or risk prognostication of HF. In the present article, we summarize the links between EAT and the heart, explaining how the study of epicardial adiposity can improve the understanding of cardiac disease, serve as a source of diagnostic and prognostic biomarkers, and as a potential therapeutic target in HF to improve clinical outcomes.

Pericardial Grafting of Cardiac Progenitor Cells in Self-Assembling Peptide Scaffold Improves Cardiac Function After Myocardial Infarction.

Many studies have explored cardiac progenitor cell (CPC) therapy for heart disease. However, optimal scaffolds are needed to ensure the engraftment of transplanted cells. We produced a three-dimensional hydrogel scaffold (CPC-PRGmx) in which high-viability CPCs were cultured for up to 8 weeks. CPC-PRGmx contained an RGD peptide-conjugated self-assembling peptide with insulin-like growth factor-1 (IGF-1). Immediately after creating myocardial infarction (MI), we transplanted CPC-PRGmx into the pericardial space on to the surface of the MI area. Four weeks after transplantation, red fluorescent protein-expressing CPCs and in situ hybridization analysis in sex-mismatched transplantations revealed the engraftment of CPCs in the transplanted scaffold (which was cellularized with host cells). The average scar area of the CPC-PRGmx-treated group was significantly smaller than that of the non-treated group (CPC-PRGmx-treated group = 46 ± 5.1%, non-treated MI group = 59 ± 4.5%; p < 0.05). Echocardiography showed that the transplantation of CPC-PRGmx improved cardiac function and attenuated cardiac remodeling after MI. The transplantation of CPCs-PRGmx promoted angiogenesis and inhibited apoptosis, compared to the untreated MI group. CPCs-PRGmx secreted more vascular endothelial growth factor than CPCs cultured on two-dimensional dishes. Genetic fate mapping revealed that CPC-PRGmx-treated mice had more regenerated cardiomyocytes than non-treated mice in the MI area (CPC-PRGmx-treated group = 0.98 ± 0.25%, non-treated MI group = 0.25 ± 0.04%; p < 0.05). Our findings reveal the therapeutic potential of epicardial-transplanted CPC-PRGmx. Its beneficial effects may be mediated by sustainable cell viability, paracrine function, and the enhancement of de novo cardiomyogenesis.

Epicardioid single-cell genomics uncovers principles of human epicardium biology in heart development and disease.

The epicardium, the mesothelial envelope of the vertebrate heart, is the source of multiple cardiac cell lineages during embryonic development and provides signals that are essential to myocardial growth and repair. Here we generate self-organizing human pluripotent stem cell-derived epicardioids that display retinoic acid-dependent morphological, molecular and functional patterning of the epicardium and myocardium typical of the left ventricular wall. By combining lineage tracing, single-cell transcriptomics and chromatin accessibility profiling, we describe the specification and differentiation process of different cell lineages in epicardioids and draw comparisons to human fetal development at the transcriptional and morphological levels. We then use epicardioids to investigate the functional cross-talk between cardiac cell types, gaining new insights into the role of IGF2/IGF1R and NRP2 signaling in human cardiogenesis. Finally, we show that epicardioids mimic the multicellular pathogenesis of congenital or stress-induced hypertrophy and fibrotic remodeling. As such, epicardioids offer a unique testing ground of epicardial activity in heart development, disease and regeneration.

The Different Pathways of Epicardial Adipose Tissue across the Heart Failure Phenotypes: From Pathophysiology to Therapeutic Target.

Epicardial adipose tissue (EAT) is an endocrine and paracrine organ constituted by a layer of adipose tissue directly located between the myocardium and visceral pericardium. Under physiological conditions, EAT exerts protective effects of brown-like fat characteristics, metabolizing excess fatty acids, and secreting anti-inflammatory and anti-fibrotic cytokines. In certain pathological conditions, EAT acquires a proatherogenic transcriptional profile resulting in increased synthesis of biologically active adipocytokines with proinflammatory properties, promoting oxidative stress, and finally causing endothelial damage. The role of EAT in heart failure (HF) has been mainly limited to HF with preserved ejection fraction (HFpEF) and related to the HFpEF obese phenotype. In HFpEF, EAT seems to acquire a proinflammatory profile and higher EAT values have been related to worse outcomes. Less data are available about the role of EAT in HF with reduced ejection fraction (HFrEF). Conversely, in HFrEF, EAT seems to play a nutritive role and lower values may correspond to the expression of a catabolic, adverse phenotype. As of now, there is evidence that the beneficial systemic cardiovascular effects of sodium-glucose cotransporter-2 receptors-inhibitors (SGLT2-i) might be partially mediated by inducing favorable modifications on EAT. As such, EAT may represent a promising target organ for the development of new drugs to improve cardiovascular prognosis. Thus, an approach based on detailed phenotyping of cardiac structural alterations and distinctive biomolecular pathways may change the current scenario, leading towards a precision medicine model with specific therapeutic targets considering different individual profiles. The aim of this review is to summarize the current knowledge about the biomolecular pathway of EAT in HF across the whole spectrum of ejection fraction, and to describe the potential of EAT as a therapeutic target in HF.

The people behind the papers - Marina Ramiro-Pareta and Ofelia Martinez-Estrada.

Wilms tumor 1 (WT1) is a transcription factor known to be expressed in the epicardium and required for heart development, but the role of WT1 outside of the epicardium is less clear. In a new paper in Development, Marina Ramiro-Pareta and colleagues generate an inducible, tissue-specific loss-of-function mouse model to investigate the role of WT1 in coronary endothelial cells (ECs). We caught up with first author Marina Ramiro-Pareta and corresponding author Ofelia Martinez-Estrada (Principal Investigator at the Institute of Biomedicine in Barcelona, Spain) to learn more about their research.

A versatile drug-controlled release polymer brush hybrid non-glutaraldehyde bioprosthetic heart valves with enhanced anti-inflammatory, anticoagulant and anti-calcification properties, and superior mechanical performance.

Transcatheter heart valve replacement (THVR) is a novel treatment modality for severe heart valves diseases and has become the main method for the treatment of heart valve diseases in recent years. However, the lifespan of the commercial glutaraldehyde cross-linked bioprosthetic heart valves (BHVs) used in THVR can only serve for 10-15 years, and the essential reason for the failure of the valve leaflet material is due to these problems such as calcification, coagulation, and inflammation caused by glutaraldehyde cross-linking. Herein, a kind of novel non-glutaraldehyde cross-linking agent bromo-bicyclic-oxazolidine (OX-Br) has been designed and synthesized with both crosslinking ability and in-situ atom transfer radical polymerization (ATRP) function. Then OX-Br treated porcine pericardium (OX-Br-PP) are stepwise modified with co-polymer brushes of reactive oxygen species (ROS) response anti-inflammatory drug conjugated block and anti-adhesion polyzwitterion polymer block through the in-situ ATRP reaction to obtain the functional BHV material MPQ@OX-PP. Along with the great mechanical properties and anti-enzymatic degradation ability similar to glutaraldehyde-crosslinked porcine pericardium (Glut-PP), good biocompatibility, improved anti-inflammatory effect, robust anti-coagulant ability and superior anti-calcification property have been verified for MPQ@OX-PP by a series of in vitro and in vivo investigations, indicating the excellent application potential as a multifunctional heart valve cross-linking agent for OX-Br. Meanwhile, the strategy of synergistic effect with in situ generations of reactive oxygen species-responsive anti-inflammatory drug blocks and anti-adhesion polymer brushes can effectively meet the requirement of multifaceted performance of bioprosthetic heart valves and provide a valuable reference for other blood contacting materials and functional implantable materials with great comprehensive performance.

Inflammatory biomarkers, angiogenesis and lymphangiogenesis in epicardial adipose tissue correlate with coronary artery disease.

In this study, we explored the relationship between inflammatory adipokine levels and coronary artery disease (CAD). We collected subcutaneous adipose tissues(SAT), pericardial adipose tissues(PAT), and epicardial adipose tissues (EAT) and serum samples from 26 inpatients with CAD undergone coronary artery bypass grafting and 20 control inpatients without CAD. Serum inflammatory adipokines were measured by ELISA. Quantitative real-time PCR and western blot were used to measure gene and protein expression. Adipocyte morphology was assessed by H&E staining. Immunohistochemistry and immunofluorescence were used to measure endothelial and inflammatory markers. Serum pro- and anti-inflammatory adipokine levels were higher and lower, respectively, in the CAD group than those in the control group (P < 0.05). In CAD, the pro-inflammatory adipokine levels via ELISA in EAT and PAT were elevated. Pro-inflammatory adipokine mRNA expression was increased, while anti-inflammatory adipokine mRNA expression decreased, in CAD relative to NCAD in EAT and PAT rather than SAT. In EAT, adipocyte area and macrophage-specific staining were lower, while lymphatic vessel marker expression was higher in CAD. Additionally, the endothelial marker expression in EAT was higher than PAT in CAD. The three tissue types had different blood vessel amounts in CAD. The regulation and imbalance expression of the novel biomarkers, including inflammatory adipokine, macrophage infiltration, angiogenesis, and lymphangiogenesis in EAT and PAT, may be related to the pathogenesis of CAD. The serum levels of inflammatory adipokines may correlate to CAD, which requires large sample size studies to get further validation before clinic practice.

Hemocompatibility tuning of an innovative glutaraldehyde-free preparation strategy using riboflavin/UV crosslinking and electron irradiation of bovine pericardium for cardiac substitutes.

Hemocompatibility tuning was adopted to explore and refine an innovative, GA-free preparation strategy combining decellularization, riboflavin/UV crosslinking, and low-energy electron irradiation (SULEEI) procedure. A SULEEI-protocol was established to avoid GA-dependent deterioration that results in insufficient long-term aortic valve bioprosthesis durability. Final SULEEI-pericardium, intermediate steps and GA-fixed reference pericardium were exposed in vitro to fresh human whole blood to elucidate effects of preparation parameters on coagulation and inflammation activation and tissue histology. The riboflavin/UV crosslinking step showed to be less efficient in inactivating extracellular matrix (ECM) protein activity than the GA fixation, leading to tissue-factor mediated blood clotting. Intensifying the riboflavin/UV crosslinking with elevated riboflavin concentration and dextran caused an enhanced activation of the complement system. Yet activation processes induced by the previous protocol steps were quenched with the final electron beam treatment step. An optimized SULEEI protocol was developed using an intense and extended, trypsin-containing decellularization step to inactivate tissue factor and a dextran-free, low riboflavin, high UV crosslinking step. The innovative and improved GA-free SULEEI-preparation protocol results in low coagulant and low inflammatory bovine pericardium for surgical application.

Endothelial deletion of Wt1 disrupts coronary angiogenesis and myocardium development.

Wt1 encodes a zinc finger protein that is crucial for epicardium development. Although WT1 is also expressed in coronary endothelial cells (ECs), the abnormal heart development observed in Wt1 knockout mice is mainly attributed to its functions in the epicardium. Here, we have generated an inducible endothelial-specific Wt1 knockout mouse model (Wt1KOΔEC). Deletion of Wt1 in ECs during coronary plexus formation impaired coronary blood vessels and myocardium development. RNA-Seq analysis of coronary ECs from Wt1KOΔEC mice demonstrated that deletion of Wt1 exerted a major impact on the molecular signature of coronary ECs and modified the expression of several genes that are dynamically modulated over the course of coronary EC development. Many of these differentially expressed genes are involved in cell proliferation, migration and differentiation of coronary ECs; consequently, the aforementioned processes were affected in Wt1KOΔEC mice. The requirement of WT1 in coronary ECs goes beyond the initial formation of the coronary plexus, as its later deletion results in defects in coronary artery formation. Through the characterization of these Wt1KOΔEC mouse models, we show that the deletion of Wt1 in ECs disrupts physiological blood vessel formation.

Human epicardial adipose tissue inflammation correlates with coronary artery disease.

BACKGROUND AND AIMS: This study investigates the expression of novel adipocytokines and inflammatory cells infiltration in epicardial adipose tissue (EAT) and subcutaneous adipose tissue (SAT) between 27 coronary artery disease (CAD) and 21 non-CAD (NCAD) patients enrolled from September 2020 to September 2021. METHODS AND RESULTS: Serum, gene, and protein expression levels of the novel adipocytokines were determined using ELISA, RT-qPCR, and western blot analyses. The number of blood vessels and adipocytes morphology were measured via hematoxylin-eosin staining, and inflammatory cells infiltration was examined via immunohistochemistry. Serum ANGPTL8, CTRP5, and Wnt5a levels were higher in the CAD than in the NCAD group, while serum CTRP3, Sfrp5, and ZAG levels were lower in the CAD than in the NCAD group. Compared to the EAT of NCAD and SAT of CAD patients, the EAT of CAD patients had higher mRNA levels of ANGPTL8, CTRP5, and Wnt5a while lower levels of CTRP3, Sfrp5, and ZAG; higher protein expression levels of ANGPTL8 and CTRP5 but lower levels of CTRP3; more blood vessels; and higher infiltration rates of macrophages (CD68 + ), pro-inflammatory M1 macrophages (CD11c + ), mast cells (Tryptase + ), T lymphocytes (CD3 + ), and B lymphocytes (CD20 + ) but lower infiltration rates of anti-inflammatory M2 macrophages (CD206 + ). CONCLUSION: Novel adipocytokines and inflammatory cells infiltration are dysregulated in human EAT, and could be important pathophysiological mechanisms and novelly promising medicating targets of CAD.