Epicardial Adipose Tissue Adipocytes Research Articles

Single-Nucleus Transcriptomic Atlas of Human Pericoronary Epicardial Adipose Tissue in Normal and Pathological Conditions.

Pericoronary epicardial adipose tissue (EAT) is a unique visceral fat depot that surrounds the adventitia of the coronary arteries without any anatomic barrier. Clinical studies have demonstrated the association between EAT volume and increased risks for coronary artery disease (CAD). However, the cellular and molecular mechanisms underlying the association remain elusive. We performed single-nucleus RNA sequencing on pericoronary EAT samples collected from 3 groups of subjects: patients undergoing coronary bypass surgery for severe CAD (n=8), patients with CAD with concomitant type 2 diabetes (n=8), and patients with valvular diseases but without concomitant CAD and type 2 diabetes as the control group (n=8). Comparative analyses were performed among groups, including cellular compositional analysis, cell type-resolved transcriptomic changes, gene coexpression network analysis, and intercellular communication analysis. Immunofluorescence staining was performed to confirm the presence of CAD-associated subclusters. Unsupervised clustering of 73 386 nuclei identified 15 clusters, encompassing all known cell types in the adipose tissue. Distinct subpopulations were identified within primary cell types, including adipocytes, adipose stem and progenitor cells, and macrophages. CD83high macrophages and FOSBhigh adipocytes were significantly expanded in CAD. In comparison to normal controls, both disease groups exhibited dysregulated pathways and altered secretome in the primary cell types. Nevertheless, minimal differences were noted between the disease groups in terms of cellular composition and transcriptome. In addition, our data highlight a potential interplay between dysregulated circadian clock and altered physiological functions in adipocytes of pericoronary EAT. ANXA1 (annexin A1) and SEMA3B (semaphorin 3B) were identified as important adipokines potentially involved in functional changes of pericoronary EAT and CAD pathogenesis. We built a complete single-nucleus transcriptomic atlas of human pericoronary EAT in normal and diseased conditions of CAD. Our study lays the foundation for developing novel therapeutic strategies for treating CAD by targeting and modifying pericoronary EAT functions.

Association of Epicardial Adipose Tissue Adipocytes Hypertrophy with Biomarkers of Low-Grade Inflammation and Extracellular Matrix Remodeling in Patients with Coronary Artery Disease

The aim of the study was to compare the morphological features of epicardial adipose tissue (EAT) adipocyte with the circulating inflammatory biomarkers and parameters of extracellular matrix remodeling in patients with coronary artery disease (CAD). We recruited 42 patients with CAD (m/f 28/14) who were scheduled for coronary artery bypass graft surgery (CABG). EAT adipocytes were obtained by the enzymatic method from intraoperative adipose tissue samples. Concentrations of secreted and lipoprotein-associated phospholipase A2 (sPLA2 and LpPLA2), TNF-α, IL-1β, IL-6, IL-10, high-sensitive C-reactive protein (hsCRP), metalloproteinase-9 (MMP-9), MMP-2, C-terminal cross-linking telopeptide of type I collagen (CTX-I), and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in blood serum. Patients were divided into two groups: group 1-with mean EAT adipocytes' size ≤ 87.32 μm; group 2-with mean EAT adipocytes' size > 87.32 μm. Patients of group 2 had higher concentrations of triglycerides, hsCRP, TNF-α, and sPLA2 and a lower concentration of CTX-I. A multiple logistic regression model was created (RN2 = 0.43, p = 0.0013). Concentrations of TNF-α, sPLA2 and CTX-I appeared to be independent determinants of the EAT adipocyte hypertrophy. ROC analysis revealed the 78% accuracy, 71% sensitivity, and 85% specificity of the model, AUC = 0.82. According to our results, chronic low-grade inflammation and extracellular matrix remodeling are closely associated with the development of hypertrophy of EAT adipocytes, with serum concentrations of TNF-α, sPLA2 and CTX-I being the key predictors, describing the variability of epicardial adipocytes' size.

Production of Reactive Oxygen Species by Epicardial Adipocytes Is Associated with an Increase in Postprandial Glycemia, Postprandial Insulin, and a Decrease in Serum Adiponectin in Patients with Severe Coronary Atherosclerosis.

Purpose. This work investigates the relations between the production of reactive oxygen species (ROS) by epicardial adipose tissue (EAT) adipocytes and parameters of glucose/insulin metabolism, circulating adipokines levels, and severity of coronary atherosclerosis in patients with coronary artery disease (CAD); establishing significant determinants describing changes in ROS EAT in this category of patients. Material and methods. This study included 19 patients (14 men and 5 women, 53–72 y.o., 6 patients with diabetes mellitus type 2; 5 patients with prediabetes), with CAD, who underwent coronary artery bypass graft surgery. EAT adipocytes were isolated by the enzymatic method from intraoperative explants obtained during coronary artery bypass grafting. The size of EAT adipocytes and ROS level were determined. Results. The production of ROS by EAT adipocytes demonstrated a direct correlation with the level of postprandial glycemia (rs = 0.62, p < 0.05), and an inverse correlation with serum adiponectin (rs = −0.50, p = 0.026), but not with general and abdominal obesity, EAT thickness, and dyslipidemia. Regression analysis demonstrated that the increase in ROS of EAT adipocytes occurs due to the interaction of the following factors: postprandial glycemia (β = 0.95), postprandial insulin (β = 0.24), and reduced serum adiponectin (β = −0.20). EAT adipocytes in patients with diabetes and prediabetes manifested higher ROS production than in patients with normoglycemia. Although there was no correlation between the production of ROS by EAT adipocytes and Gensini score in the total group of patients, higher rates of oxidative stress were observed in EAT adipocytes from patients with a Gensini score greater than median Gensini score values (≥70.55 points, Gr.B), compared to patients with less severe coronary atherosclerosis (<70.55 points, Gr.A). Of note, the frequency of patients with diabetes and prediabetes was higher among the patients with the most severe coronary atherosclerosis (Gr.B) than in the Gr.A. Conclusions. Our data have demonstrated for the first time that systemic impairments of glucose/insulin metabolism and a decrease in serum adiponectin are significant independent determinants of oxidative stress intensity in EAT adipocytes in patients with severe coronary atherosclerosis. The possible input of the interplay between oxidative stress in EAT adipocytes and metabolic disturbances to the severity of coronary atherosclerosis requires further investigation.

The level of reactive oxygen species production by adipocytes of epicardial adipose tissue is associated with an increase in postprandial glycemia in patients with severe coronary atherosclerosis

The mechanisms of oxidative stress in adipocytes of local fat depots in patients with cardiometabolic diseases have been studied insufficiently.Purpose. To study the levels of reactive oxygen species (ROS) production in adipocytes of epicardial (EAT) and subcutaneous adipose tissue (SAT) in patients with stable coronary artery disease (CAD) and severe coronary atherosclerosis who underwent coronary artery bypass grafting; to investigate the potential relationships between the levels of ROS production by EAT and SAT adipocytes and obesity parameters, EAT accumulation, basal and postprandial glycemia, and blood lipid transport function.Material and Methods. The study included 19 patients (12 men and 7 women including 6 patients (31.5%) with type 2 diabetes mellitus) aged 53–72 years with stable CAD and severe coronary atherosclerosis. The material for the study was EAT and SAT adipocytes obtained by the enzymatic method from intraoperative explants. The ROS level in adipocytes was determined using the fluorimetry with 2,3-dihydrodichlorofluorescein diacetate. Anthropometric parameters of obesity and EAT thickness were studied using echocardiography. The blood lipid transport function and the levels of basal and postprandial glucose were assessed.Results. The levels of ROS production by EAT and SAT adipocytes in the overall group of patients did not differ significantly and amounted to 1710 (1608; 2079) and 1876 (1374; 2215) arbitrary units, respectively. The level of ROS production by SAT adipocytes did not correlate with the parameters of obesity, EAT thickness, or biomarker levels. The level of ROS production by EAT adipocytes directly correlated with the level of postprandial glycemia (rs = 0.62, p &lt; 0.05), but did not correlate with measures of general and abdominal obesity, EAT thickness, and dyslipidemia. The level of ROS production by EAT adipocytes in patients with postprandial glycemia ≥ 7.7 mmol/L (n = 9) exceeded the corresponding value in patients with lower level of postprandial glycemia (n = 10): 2079 (1710; 2458) against 1625.5 (1332; 1699) arbitrary units (p = 0.015), respectively.Conclusion. We showed for the first time that the level of ROS production by EAT adipocytes in CAD patients with severe coronary atherosclerosis was directly associated with the level of postprandial glycemia. The highest level of ROS production in EAT adipocytes occurred in these patients when the level of postprandial glycemia exceeds 7.7 mmol/L.

Relationships between the expression of adipocytokine genes and the calcification of coronary arteries in patients with coronary artery disease

Dysfunctional changes and remodeling of adipose tissue (АT) are associated with the formation of microcalcifications in the vascular wall. Biologically active substances synthesized by АT (adipocytokines) can act as promoters and inhibitors of vascular calcification development. The few available experimental and clinical studies do not fully explain the possible mechanisms of these effects.Aim. To study the relationships between the adipocytokine profiles of adipocytes in epicardial and perivascular AT with the severity of coronary artery calcification in patients with coronary artery disease (CAD).Material and Methods. A total of 125 patients with CAD aged 59 (53; 66) years were examined. The isolated adipocytes of subcutaneous adipose tissue (SAT), epicardial adipose tissue (EAT), and perivascular adipose tissue (PVAT), obtained during coronary artery bypass grafting, were used to determine gene expression and secretion of adipocytokines (adiponectin, leptin, and IL-6). Expression of adipocytokine genes was assessed using quantitative PCR with detection of products in real time (real-time qPCR); the concentration of adipocytokines in the culture medium was determined by enzyme-linked immunosorbent assay using R&amp;D Systems kits (Canada). Coronary artery (CA) calcification degree was assessed by multislice spiral computed tomography (MSCT) method. The calcium index of CA was determined by the Agatston method using the Syngo Calcium Scoring software package (Siemens AG Medical Solution, Germany).Results. Massive coronary calcification (CC) had the highest prevalence (58.8%) in patients with CAD. The highest level of expression of the ADIPOQ gene in all types of fat stores was observed in patients with moderate/medium CС compared to those with massive CС; the maximum expression of ADIPOQ was observed in the culture of PVAT adipocytes. Expression of the LEP and IL6 genes in massive CC was higher, with the maximum values in the culture of EAT adipocytes relative to SAT and PVAT adipocytes. Decreases in the levels of ADIPOQ mRNA and its secretion, increases in the levels of mRNA of LEP and IL6 and their secretion in adipocytes of the EAT and PVAT were associated with the development of СС in patients with CAD.Conclusion. Proinflammatory adipokines produced by adipocytes of patients with CAD during hypoxia induced vascular calcification by stimulating oxidative stress, osteoblast differentiation, apoptosis, and proliferation of smooth muscle cells. Endothelial cells, when stimulated with proinflammatory adipocytokines, tended to transform into osteoblasts, which further aggravated the degree of vascular inflammation and calcification.

Hypertrophy and Insulin Resistance of Epicardial Adipose Tissue Adipocytes: Association with the Coronary Artery Disease Severity.

Changes in the structural and functional characteristics of the epicardial adipose tissue (EAT) are recognized as one of the factors in the development of cardiometabolic diseases. However, the generally accepted quantitative assessment of the accumulation of EAT does not reflect the size of adipocyte and presence of adipocyte hypertrophy in this fat depot. Overall contribution of adipocyte hypertrophy to the development and progression of coronary atherosclerosis remains unexplored. Objective: To compare the morphological characteristics of EAT adipocyte and its sensitivity to insulin with the CAD severity, as well as to identify potential factors involved in the realization of this relationship. The present study involved 24 patients (m/f 16/8) aged 53–72 years with stable CAD, who underwent coronary artery bypass graft surgery. Adipocytes were isolated enzymatically from EAT explants obtained during the operation. The severity of CAD was assessed by calculating the Gensini score according to selective coronary angiography. Insulin resistance of EAT adipocytes was evaluated by reactivity to insulin. In patients with an average size of EAT adipocytes equal to or exceeding the median (87 μm) the percentage of hypertrophic adipocytes was twice as high as in patients in whom the average size of adipocytes was less than 87 μm. This group of patients was also characterized by the higher rate of the Gensini score, lower adiponectin levels, and more severe violation of carbohydrate metabolism. We have revealed direct nonparametric correlation between the size of EAT adipocytes and the Gensini score (rs = 0.56, p = 0.00047). The number of hypertrophic EAT adipocytes showed a direct nonparametric correlation with the Gensini score (rs = 0.6, p = 0.002). Inverse nonparametric correlations were found between the serum adiponectin level and size (rs = −0.60, p = 0.001), hypertrophy of adipocytes (rs = −0.67, p = 0.00), and Gensini score (rs = −0.81, p = 0.00007). An inverse nonparametric correlation was found between the Gensini score and sensitivity of EAT adipocytes to insulin, estimated by the intracellular redox response (rs = −0.90, p = 0.037) and decrease in lipolysis rate upon insulin addition (rs = −0.40, p = 0.05). The intracellular redox response of adipocytes to insulin was directly correlated with fasting insulin and inversely with postprandial insulin. Our data indicate that the size and degree of hypertrophy of the epicardial adipocytes are related to the CAD severity. According to our results, insulin resistance of adipocytes may be considered as one of the factors mediating this relationship.

R31 Relationship Between Epicardial Adipose Tissue Thickness and Epicardial Adipocyte Size with Increasing Body Mass Index

Macroscopic deposition of epicardial adipose tissue (EAT) has been strongly associated with numerous indices of obesity and cardiovascular disease risk. In contrast, the morphology of the adipocytes comprising EAT, both in cardio-metabolic health and disease, has rarely been investigated. We aimed to determine whether obesity-driven adipocyte hypertrophy, which is characteristic of other visceral fat depots, is found within EAT adipocytes.

P3482Leptin, receptor to leptin and expression in adipocytes isolated from different adipose depots in patients with ischemic heart disease

Abstract Purpose To study the peculiarities of the content of leptin and the leptin receptor in adipocyte culture of subcutaneous (SAT), epicardial (EAT) and perivascular (PVAT) adipose tissue and the expression of their genes. Methods 29 patients with coronary heart disease were examined. Adipocytes were isolated from SAT, EAT and PVAT samples obtained during coronary artery bypass grafting, followed by evaluation (after 24 hours) of the leptin concentration (Human resistin ELISA, R&amp;D Systems, USA) and leptin gene expression in cell culture. Magnetic resonance imaging (MRI) was used to determine the area of the visceral (VAT) and subcutaneous adipose tissue (SAT) of the abdominal region, the thickness of epicardial adipose tissue (EAT). The calculation of the free leptin index (FLI) was determined by the formula: leptin/SOB-R * 100. Leptin resistance was defined as an FLI &gt;0.25. All study was carried out in compliance with the Helsinki Declaration, and its protocol was approved by the Ethical Committee of Research Institute. Statistical analysis was performed using Statistica 10.0. Results In adipocytes of EAT, leptin secretion was 1.2 times higher than in adipocytes of PVAT, which is consistent with the expression of the leptin gene. The content of leptin soluble receptor was opposite in the adipocytes of PVAT higher than in EAT and SAT 2.3 and 3.1 times, respectively. At the same time, the index of free leptin was higher in SAT adipocytes 1.3 and 3.2 times in comparison with EAT and PVAT. The correlation analysis confirmed the relationship between EAT thickness and the serum concentrations of leptin. Thus, in patients with VO, the leptin concentration had a negative dependence on the thickness of the left and right ventricle (r=−0.28, p=0.02; r=−0.33, p=0.02, respectively). A negative dependence on the EAT thickness was also established for the FLI (r=−0.28; p=0.03). PVAT of the abdominal aorta is similar to the properties of visceral AT. An analysis of the possible relationship between perivascular adipocytes and adipokine exchange rates showed a direct relationship between the volume PVAT of the abdominal aortic ventricle and leptin (r=0.44, p=0.01), as well as the FLI (r=0.56; p=0.03). Conclusion Adipocytes SAT, EAT and PVAT differed in the level of secretion of leptin. In epicardial and, to a greater extent, in perivascular adipocytes, a protective mechanism against a high concentration of leptin was observed due to increased secretion of the soluble receptor to leptin. The high content of leptin and the low soluble receptor for leptin led to the development of leptin resistance, which was more pronounced in the culture of adipocytes SAT. Meanwhile, the EAT thickness was inversely related to the concentration of leptin and the FLI index (one of the main leptin-resistance markers).

Localization profiles of natriuretic peptides in hearts of pre-hibernating and hibernating Anatolian ground squirrels (Spermophilus xanthoprymnus).

The Anatolian ground squirrel (Spermophilus xanthoprymnus) is a typical example of true mammalian hibernators. In order to adapt to extreme external and internal environments during hibernation, they lower their body temperatures, heart rates and oxygen consumption; however, pathological events such as ischemia and ventricular fibrillation do not occur in their cardiovascular systems. During the hibernation, maintenance of cardiac function is very important for survival of ground squirrels. Natriuretic peptides (NPs) are key factors in the regulation of cardiovascular hemostasis. Since NPs' role on the protection of heart during hibernation are less clear, the aim of this study was to investigate dynamic changes in NPs content in the cardiac chambers and to reveal the possible role of NPs on establishing cardiac function in ground squirrel during hibernation using immunohistochemistry. The immunohistochemical results indicate that cardiac NP expressions in atrial and ventricular cardiomyocytes were different from each other and were sex-independent. ANP and BNP were expressed in a chamber-dependent manner in female and male squirrel hearts. Furthermore, cardiac NPs expression levels in hibernation period were lower than those at the pre-hibernation period. During prehibernation period, ANP, BNP and CNP were expressed in the white and beige adipocytes of epicardial adipose tissue (EAT); while during hibernation period, the brown adipocytes of EAT were positive for BNP and CNP. These data suggest that the hibernation-dependent reduction in levels of NPs, particularly ANP, in cardiac chambers and EAT may be associated with low heart rate and oxygen consumption during hibernation. However, further studies are needed to better delineate the roles of NPs during the hibernation.

Relationship between epicardial adipose tissue thickness and epicardial adipocyte size with increasing body mass index

ABSTRACTMacroscopic deposition of epicardial adipose tissue (EAT) has been strongly associated with numerous indices of obesity and cardiovascular disease risk. In contrast, the morphology of EAT adipocytes has rarely been investigated. We aimed to determine whether obesity-driven adipocyte hypertrophy, which is characteristic of other visceral fat depots, is found within EAT adipocytes. EAT samples were collected from cardiac surgery patients (n = 49), stained with haematoxylin & eosin, and analysed for mean adipocyte size and non-adipocyte area. EAT thickness was measured using echocardiography. A significant positive relationship was found between EAT thickness and body mass index (BMI). When stratified into standardized BMI categories, EAT thickness was 58.7% greater (p = 0.003) in patients from the obese (7.3 ± 1.8 mm) compared to normal (4.6 ± 0.9 mm) category. BMI as a continuous variable significantly correlated with EAT thickness (r = 0.56, p < 0.0001). Conversely, no correlation was observed between adipocyte size and either BMI or EAT thickness. No difference in the non-adipocyte area was found between BMI groups. Our results suggest that the increased macroscopic EAT deposition associated with obesity is not caused by adipocyte hypertrophy. Rather, alternative remodelling via adipocyte proliferation might be responsible for the observed EAT expansion.

Adipokine-cytokine profile of adipocytes of epicardial adipose tissue in ischemic heart disease complicated by visceral obesity

Introduction. To date, cardiovascular diseases (CVD) remain the main cause of disability and mortality in population. The majority of ectopic fat deposits demonstrated a reliable association with cardiometabolic risks and clinical manifestations of most CVD. The elucidation of the metabolic features of adipocytes of epicardial adipose tissue localized in the immediate vicinity of the lesion in ischemic heart disease (IHD) can have both theoretical and practical significance for pathophysiology and cardiology.&#x0D; Aim. To study the adipokine-cytokine profile of epicardial adipocytes (EA) and subcutaneous adipose tissue (SCAT), blood serum in relation to the area of visceral adipose tissue (AVAT), biochemical and rhelinic characteristics of IHD patients.&#x0D; Methods. 84 patients (70 men and 14 women) with IHD were examined. In the presence of visceral obesity (VO), patients were divided into two groups. In patients with VO, adipocyte EA and SCAT were sampled, followed by cultivation and evaluation of adipokine and proinflammatory activity. The parameters of carbohydrate and lipid metabolism, adipokine and proinflammatory status in blood serum were determined.&#x0D; Results. It has been established that the adipokine-cytokine profile of the adipocytes EA and SCAT differ. Adipocytes of EA in IHD on the background of VO are characterized by an increase in IL-1, TNF-, leptin-adiponectin ratio and a decrease in the protective factors: adiponectin and anti-inflammatory cytokine IL-10. While adipocytes of SCAT were characterized by a decrease in the concentration of the soluble receptor to leptin and a more pronounced leptin resistance, and the increase in inflammatory cytokines was compensated by an increase in the concentration of IL-10, the presence of VO was associated with multivessel coronary disease, multifocal atherosclerosis, insulin resistance, atherogenic dyslipidemia, adipokine imbalance, and markers of inflammation. Thus, the value of the area of VO determined higher values of leptin concentration, TNF- in adipocytes and serum, lipid and carbohydrate metabolism and a lower soluble receptor for leptin content.&#x0D; The conclusion. Thus, in IHD with VO the state of adipocytes, EA is characterized as "metabolic inflammation" and may indicate the direct involvement of adipocytes in the pathogenesis of IHD due to the formation of adipokine imbalance and the activation of proinflammatory reactions.

Adipokine and Cytokine Profiles of Epicardial and Subcutaneous Adipose Tissue in Patients with Coronary Heart Disease.

The content of adipokines, pro- and anti-inflammatory cytokines were studied in adipocytes isolated from epicardial and subcutaneous adipose tissue of 24 coronary heart disease patients. The content of leptin and soluble leptin receptor in adipocytes of epicardial adipose tissue was higher by 28.6 and 56.9% and the level of adiponectin was lower by 33% than in adipocytes of the subcutaneous fat. In culture of epicardial adipocytes, the levels of proinflammatory cytokines TNF-α and IL-1 were higher. Subcutaneous adipose tissue adipocytes were characterized by higher levels of anti-inflammatory cytokines IL-10 and FGF-β. In epicardial adipocytes of coronary heart disease patients, the concentrations of leptin, TNF-α, and IL-1 were higher, while the levels of defense regulatory molecules (adiponectin, IL-10, and FGF-β) were lower than in subcutaneous adipocytes.

Atrial natriuretic peptide regulates adipose tissue accumulation in adult atria

The abundance of epicardial adipose tissue (EAT) is associated with atrial fibrillation (AF), the most frequent cardiac arrhythmia. However, both the origin and the factors involved in EAT expansion are unknown. Here, we found that adult human atrial epicardial cells were highly adipogenic through an epithelial-mesenchymal transition both in vitro and in vivo. In a genetic lineage tracing the WT1CreERT2+/-RosatdT+/- mouse model subjected to a high-fat diet, adipocytes of atrial EAT derived from a subset of epicardial progenitors. Atrial myocardium secretome induces the adipogenic differentiation of adult mesenchymal epicardium-derived cells by modulating the balance between mesenchymal Wingless-type Mouse Mammary Tumor Virus integration site family, member 10B (Wnt10b)/β-catenin and adipogenic ERK/MAPK signaling pathways. The adipogenic property of the atrial secretome was enhanced in AF patients. The atrial natriuretic peptide secreted by atrial myocytes is a major adipogenic factor operating at a low concentration by binding to its natriuretic peptide receptor A (NPRA) receptor and, in turn, by activating a cGMP-dependent pathway. Hence, our data indicate cross-talk between EAT expansion and mechanical function of the atrial myocardium.