Human Epicardial Adipose Tissue Research Articles

Tissue-resident memory T cells in epicardial adipose tissue comprise transcriptionally distinct subsets that are modulated in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia and carries an increased risk of stroke and heart failure. Here we investigated how the immune infiltrate of human epicardial adipose tissue (EAT), which directly overlies the myocardium, contributes to AF. Flow cytometry analysis revealed an enrichment of tissue-resident memory T (TRM) cells in patients with AF. Cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) and single-cell T cell receptor (TCR) sequencing identified two transcriptionally distinct CD8+ TRM cells that are modulated in AF. Spatial transcriptomic analysis of EAT and atrial tissue identified the border region between the tissues to be a region of intense inflammatory and fibrotic activity, and the addition of TRM populations to atrial cardiomyocytes demonstrated their ability to differentially alter calcium flux as well as activate inflammatory and apoptotic signaling pathways. This study identified EAT as a reservoir of TRM cells that can directly modulate vulnerability to cardiac arrhythmia.

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.

Insights into beige phenotype and immune cell dynamics of human epicardial adipose tissue.

Insights into beige phenotype and immune cell dynamics of human epicardial adipose tissue.

Human epicardial adipose tissue contains innate and adaptive lymphoid cells and a higher proportion of innate type 2 lymphoid cells compared to other adipose tissues

ImportanceEpicardial adipose tissue (EAT) is a biologically active organ surrounding myocardium and coronary arteries that has been associated with coronary artery disease (CAD) and atrial fibrillation. Previous work has shown that EAT exhibits beige features. ObjectiveOur objective was to determine whether the stromal vascular fraction of the human EAT contains innate or adaptive lymphoid cells compared to thoracic subcutaneous (thSAT), visceral abdominal (VAT) and subcutaneous abdominal (abSAT). ParticipantsNew pangenomic microarray analysis was performed on previous transcriptomic dataset using significance analysis of microarray and ingenuity pathway analysis (n=41) to identify specific immune signature and its link with browning genes. EAT, thSAT, VAT and abSAT samples from explanted patients with severe cardiomyopathies and multi-organ donor patients (n=17) were used for flow cytometry (FC) immunophenotyping assay. Patients were on average 55±16 years-old; 47% had hypertension and 6% CAD. Phenotypic adaptive and innate immune profiles were performed using a TBNK panel and a specific ILC1-2-3 panel including CD127, CD117, CRTH2 (CD294) and activation markers such as CD25 and CD69. ResultsTranscriptomic analysis showed a significant positive correlation between the TH2 immune pathway (IL-4, IL-5, IL-13, IL-25, IL-33) and browning genes (UCP-1, PRDM16, TMEM26, CITED1, TBX1) in EAT versus thSAT (R=0.82, P<0.0001). Regarding adaptive immune cells, a preponderance of CD8T cells, a contingent of CD4T cells, and a few B cells were observed in all ATs (P<0.0001). In innate lymphoid cells (ILCs), an increase was observed in visceral ATs (i.e. EAT; VAT 35±8ILCs/g of tissue) compared to their subcutaneous counterpart (i.e. thSAT+abSAT: 8±3 ILCs/g of AT, P=0.002), with a difference in the proportion of the 3 subtypes of ILCs (ILC1>ILC3>ILC2). In addition, we observed an increase in EAT-ILC2 compared to other ATs and almost all these EAT-ILC2 expressed CD69 and/or CD25 activation markers (99.75±0.16%; P<0.0001). We also observed more NKs in EAT and VAT (1520±71 cells/g of AT) than in SATs (562±17 cells/g of AT); P=0.01. ConclusionThis is the first study to provide a comparison between innate and adaptive lymphoid cells in human epicardial versus abdominal or thoracic adipose tissues. Further studies are ongoing to decipher whether these cells could be involved in EAT beiging. Trial RegistrationCODECOH No. DC-2021-4518 The French agency of biomedicine PFS21-005.

Human epicardial fat has a beige profile and contains higher type 2 innate lymphoid cells than subcutaneous fat.

Epicardial adipose tissue (EAT) is a visceral fat that has been associated with coronary artery disease and atrial fibrillation. Previous work has revealed that EAT exhibits beige features. First, a new pan-genomic microarray analysis was performed on previously collected paired human EAT and thoracic subcutaneous AT (thSAT) from the EPICAR study (n = 31) to decipher a specific immune signature and its link with browning genes. Then, adaptive (T and B cells) and innate lymphoid cell (ILC1, ILC2, and ILC3) immunophenotyping assay panels, including CD127, CD117, and prostaglandin D2 receptor 2, were performed on prospectively collected paired human multiorgan donors (n = 18; INTERFACE study). In the EPICAR study, a positive correlation between the T helper cell subtype Th2 immune pathway and browning genes was found in EAT versus thSAT (r = 0.82; p < 0.0001). In the INTERFACE study, this correlation was also observed (r = 0.31; p = 0.017), and a preponderance of CD4+T cells, CD8+T cells, and a few B cells was observed in all ATs (p < 0.0001). An increase in ILCs was observed in visceral AT (VAT) (i.e., EAT + VAT; 30 ± 5 ILCs per gram of AT) compared with subcutaneous counterparts (i.e., thSAT + abdominal SAT; 8 ± 2 ILCs per gram of AT; p = 0.001), with ILC1 being the most frequent (ILC1 > ILC3 > ILC2). Numbers of ILCs per gram of AT correlated with several Th2 or browning genes (IL-13, TNF receptor superfamily member 9 [TNFRSF9], and alkaline phosphatase, biomineralization associated [ALPL]). Interestingly, a specific increase in EAT-ILC2 compared with other ATs was observed, including a significant proportion expressing CD69 and/or CD25 activation markers (97.9% ± 1.2%; p < 0.0001). Finally, more natural killer cells were observed in EAT + VAT than in thSAT + abdominal SAT (p = 0.01). Exclusion of patients with coronary artery disease in the EPICAR and INTERFACE studies did not modify the main findings. Gene expression phenotyping confirmed specific upregulation of Th2 pathway and browning genes (IL-33 and uncoupling protein 1 [UCP-1]) in EAT. This is the first study, to our knowledge, to provide a comparison between innate and adaptive lymphoid cells in human EAT. Further studies are ongoing to decipher whether these cells could be involved in EAT beiging.

The thrombin receptor PAR4 supports visceral adipose tissue inflammation.

Thrombin inhibition suppresses adiposity, WAT inflammation and metabolic dysfunction in mice. Protease-activated receptor (PAR)1 does not account for thrombin-driven obesity, so we explored the culprit role of PAR4 in this context. Male WT and PAR-4-/- mice received a high fat diet (HFD) for 8 weeks, WT controls received standard chow. Body fat was quantified by NMR. Epididymal WAT was assessed by histology, immunohistochemistry, qPCR and lipase activity assay. 3T3-L1 preadipocytes were differentiated ± thrombin, acutely stimulated ± PAR4 activating peptide (AP) and assessed by immunoblot, qPCR and U937 monocyte adhesion. Epicardial adipose tissue (EAT) from obese and lean patients was assessed by immunoblot. PAR4 was upregulated in mouse WAT under HFD. PAR4-/- mice developed less visceral adiposity and glucose intolerance under HFD, featuring smaller adipocytes, fewer macrophages and lower expression of adipogenic (leptin, PPARγ) and pro-inflammatory genes (CCL2, IL-1β) in WAT. HFD-modified activity and expression of lipases or perilipin were unaffected by PAR4 deletion. 3T3-L1 adipocytes differentiated with thrombin retained Ki67 expression, further upregulated IL-1β and CCL2 and were more adhesive for monocytes. In mature adipocytes, PAR4-AP increased phosphorylated ERK1/2 and AKT, upregulated Ki67, CCl2, IL-β and hyaluronan synthase 1 but not TNF-α mRNA, and augmented hyaluronidase-sensitive monocyte adhesion. Obese human EAT expressed more PAR4, CD68 and CD54 than lean EAT. PAR4 upregulated in obesity supports adipocyte hypertrophy, WAT expansion and thrombo-inflammation. The emerging PAR4 antagonists provide a therapeutic perspective in this context beyond their canonical antiplatelet action.

Human epicardial adipose tissue-secreted miR-92a-3p regulates myocardial redox state via paracrine signalling: implications for cardiovascular clinical outcomes

Abstract Background Visceral obesity is directly linked to increased cardiovascular risk, including heart failure. Purpose We explored the ability of human epicardial adipose tissue (EAT)-derived microRNAs (miRNAs) to regulate the myocardial redox state and clinical outcomes. Methods The 5 study arms included 466 patients undergoing cardiac surgery to perform: 1) the discovery phase in which we screened for 351 miRNAs expressed and released from human EAT; 2) correlation analyses between EAT microRNAs and myocardial expression of their targets or myocardial superoxide production in paired EAT/atrial biopsies; 3) genome-wide association screening for miR-92a-3p expression in EAT to test causality/directionality; 4) ex vivo experiments to investigate the underlying mechanisms that were also studied in vitro and in vivo; 5) an 8-year follow-up study to test the prognostic value of the discovered miRNA. Superoxide (O2.-) generation was measured by lucigenin chemiluminescence with NADPH 100μM stimulation as indicator of NADPH-oxidases activity. Vas2870 400 μM (a specific pan-NADPH oxidase inhibitor) was used to obtain the Vas2870-inhibitable O2.- signal which constitutes a more specific index of NADPH oxidase activity. Activation of Rac1, a key NADPH-oxidases subunit, was evaluated by a commercially available kit. Differentiated H9c2 cells were used as an in vitro model of cardiomyocytes. Doxycycline-inducible Wnt5a-overexpressing mice were used for in vivo experiments. Results The EAT secretome profiling on study 1 patients led us to identify 3 microRNAs both expressed and released by EAT whose levels in EAT correlated with oxidative stress in human myocardium. Among these miRNAs only miR-92a-3p reduced NADPH-oxidase-derived superoxide (O2.-) in cardiomyocytes (A). A genetic screening identified 7 SNPs that were associated with high miR-92a-3p levels in EAT (EAT-miR-92a-3p SNPs) and were related to lower myocardial superoxide production (B). miR-92a-3p decreased both activation of Rac1 (not shown) and Wnt5a protein levels in vitro (C). Patients with high EAT miR-92a-3p levels had lower WNT5A levels in the myocardium (not shown). Ex vivo, in vivo and in vitro experiments showed opposite effects of Wnt5a on Rac1-mediated NADPH-oxidases activity (D and not shown). Finally, we found an association of miR-92a-3p levels in EAT with lower relative risk of adverse cardiovascular events (E). Conclusions EAT-derived miRNAs exert paracrine effects on the human heart. Indeed miR-92a-3p suppresses the Wnt5a/Rac1/NADPH oxidase axis and improves myocardial redox state. EAT-derived miR-92a-3p is related with improved clinical outcomes and is a rational therapeutic target for the prevention and treatment of obesity-related heart disease.

Empagliflozin suppresses the differentiation/maturation of human epicardial preadipocytes and improves paracrine secretome profile

Abstract Aims Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the epicardial adipose tissue (EAT) in human, which could enhance the cardioprotective effect in heart failure and atrial fibrillation. However, the precise mechanism of EAT reduction remains unclear. We investigated the direct effect of SGLT2 inhibitor, empagliflozin, on human primary epicardial adipocyte and preadipocyte. Methods and Results In Arm1, human EAT biopsies obtained during surgery and isolated preadipocyte/adipocytes were used for evaluating SGLT2 expression. In Arm2 and Arm3, we investigated the direct effect of empagliflozin on the differentiation/maturation and secretome profile of human preadipocyte/adipocyte. We validated the effect of empagliflozin on paracrine effect of EAT using co-culture with human iPS-derived atrial cardiomyocytes and empagliflozin-treated human epicardial adipocyte in Arm4. The validity of findings obtained from Arm1-4 were verified in view of clinical perspective in Arm5 and Arm6. SGLT2 was mainly expressed in the human pre-adipocyte in EAT. The expression levels of SGLT2 significantly diminished when the pre-adipocyte terminally differentiated. The formation of lipid droplets and fatty acid binding protein 4 (FABP4) expression in adipocyte were attenuated by empagliflozin treatment without affecting cell proliferation. mRNA levels of IL1α, IL1β, IL6, TGFβ and MCP1 in empagliflozin-treated adipocyte were significantly decreased. Of these, secreted protein levels of IL6 and MCP1 were significantly downregulated in supernatant of empagliflozin-treated cells. Co-culture of human iPS-derived atrial cardiomyocytes and adipocyte pre-treated with or without empagliflozin revealed that empagliflozin had striking suppressive effects on myocardial oxidative stress. Only IL6 mRNA expression in human EAT showed the clinically relevant association in terms of the difference of AF prevalence, anti-diabetic drug and N-terminal pro-brain natriuretic peptide. Conclusions We demonstrated that empagliflozin suppresses human epicardial pre-adipocyte differentiation/maturation, possibly leading to the reduction of EAT volume, and improves paracrine secretome profile of EAT. IL6 might be a key adipokine regulated by SGLT2 inhibitors.

A novel role of human epicardial adipocyte-derived SPARCL1 in suppression of postoperative atrial fibrillation in patients undergoing cardiovascular surgery

Abstract Background Postoperative atrial fibrillation (POAF) occurs in 20-50% after cardiovascular surgery and is closely associated with the short and long-term morbidity/mortality. The epicardial adipose tissue (EAT) is in contact with the atrial muscle, and may have a potential predisposing factor to induce POAF within it. Purpose We tried to identify the specific gene expression profile of the human epicardial adipocyte associated with POAF. Methods We prospectively evaluated 126 patients without a history of AF (male 86 (68.3%); mean age 68.3 ± 11.7) who underwent scheduled open-heart cardiovascular surgery between May 2020 and November 2022. They were assigned to the POAF group and the Non-POAF group. POAF was defined as AF lasting more than 30 seconds documented by monitor or 12-lead electrocardiogram after the operation. Fresh human EAT samples were obtained from these patients during surgery, and preadipocytes were isolated from these samples. Isolated preadipocytes were terminally differentiated to mature adipocytes and RNAs were extracted. Genome-wide expression profiling of 6 vs. 6 matched samples of the POAF and Non-POAF groups was performed using Human Clariom S Assay-HT 16-Array Plate. The secreted protein levels in the adipocytes-cultured medium were also evaluated using enzyme-linked sorbent assay test to confirm the consistency of mRNA expression levels of adipocytes and its secreted protein levels. Results POAF was observed in 48 patients (38%). Patients in the POAF group were significantly older (p = 0.003) compared to the Non-POAF group. POAF occurred mainly within the first 3 postoperative days (median 2.5 days), and the median duration of POAF was 298 ± 581 minutes. The occurrence of POAF was significantly associated with longer postoperative hospitalization (p = 0.001) and intensive care unit stay (p = 0.04). Microarray analysis revealed that there were 132 down- or up-regulated cording genes (fold change &amp;gt;2.0 or `−2.0, p &amp;lt; 0.05) in epicardial adipocytes of the Non-POAF group compared to the POAF group. Of these genes, 11 genes cording secretable molecules were validated by qPCR, showing that only SPARCL1 had significantly higher expression in the Non-POAF group compared to the POAF group (p = 0.008). The mRNA expression levels of SPARCL1 significantly decreased when the preadipocyte were terminally differentiated to the mature adipocyte (p = 0.0009). SPARCL1 mRNA expression in adipocyte was significantly correlated with the concentration of SPARCL1 protein in the adipocyte-cultured medium (p &amp;lt; 0.0001, r = 0.7476). Conclusion The results of this study suggest that the expression of SPARCL1 in human epicardial adipocytes may play an important role in the suppression of POAF. Our findings suggested that SPARCL1 expression in human epicardial adipocytes may play an important role in the suppression of POAF. SPARCL1 secreted by epicardial adipocytes may be a potential therapeutic target for POAF prevention.Flowchart of patient selectionMicroarray analysis and qPCR varidation

Abstract 12698: Myocardial Infiltration of the Epicardial Adipose Tissue in Human Heart Failure

Introduction: The epicardial adipose tissue (EAT) is adipose tissue that is contiguous with the myocardium without barrier. However, there is a fundamental gap in knowledge for the EAT’s role in health and disease. Methods: We employed single-nucleus RNA sequencing (snRNAseq) and molecular techniques to phenotype human EAT procured from patients with heart failure (HF) secondary to dilated cardiomyopathy (DCM) and ischemic heart disease (IHD). EAT was harvested from the right and left ventricles (RV and LV) of 10 healthy control (CTRL) donors ((median age: 54.0 (interquartile range [IQR]: 49.0-57.9) years; 5 [50.0%] males; median BMI: 25.0 ([IQR]: 24.5-28.2) kg/m 2 ), 32 DCM patients ((median age: 55.0 (interquartile range [IQR]: 48.0-60.7) years; 16 [50.0%] males; median BMI: 26.1 ([IQR]: 23.0-30.3) kg/m 2 ) and 22 IHD patients ((median age: 57.5 (interquartile range [IQR]: 52.5-64.5) years; 13 [59.1%] males; median BMI: 27.2 ([IQR]: 25.1-30.7) kg/m 2 ). HF patients were age (p=0.668 (DCM); p=0.172 (IHD)), sex (p&gt;0.999 (DCM); p=0.712 (IHD)), and BMI (p=0.711 (DCM); p=0.515 (IHD)) matched to CTRL. Results: There was a significant expansion of EAT over the LV (mean EAT thickness in CTRL: 1.11mm, DCM: 2.75mm (p=0.002) and IHD: 3.31mm (p&lt;0.001)) and the RV (mean EAT thickness in CTRL: 2.24mm, DCM: 5.57mm (p=0.029) and IHD: 5.11mm (p=0.065)) in HF. There was only a regional expansion of EAT over the LV of IHD patients. Data were analyzed using one-way ANOVA with Tukey’s post hoc test. Histological staining revealed myocardial EAT infiltration in HF, which was absent in CTRL. Nuclei isolated from EAT and adjacent myocardium were then subjected to snRNAseq. The transcriptional signature of HF intramyocardial adipocytes closely resembled unique cell states and gene expression identified in the EAT, suggesting infiltration by the EAT. By contrast, myocardial adipocytes in CTRL tissue were distinct from the EAT. The adipocytes in the interventricular septum, which lacks contiguous EAT, were similar in HF and CTRL. Conclusion: The proximity of the EAT confers a unique position to directly modulate the myocardium. As such, targeting pathogenic EAT expansion and infiltration may be critical to the development of novel therapeutic strategies in HF patients.

Empagliflozin Suppresses the Differentiation/Maturation of Human Epicardial Preadipocytes and Improves Paracrine Secretome Profile

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce epicardial adipose tissue (EAT) in humans, enhancing cardioprotective effects on heart failure and atrial fibrillation. We investigated the direct effect of the SGLT2 inhibitor empagliflozin on human primary epicardial adipocytes and preadipocytes. SGLT2 is primarily expressed in human preadipocytes in the EAT. The expression levels of SGLT2 significantly diminished when the preadipocytes were terminally differentiated. Adipogenesis of preadipocytes was attenuated by empagliflozin treatment without affecting cell proliferation. The messenger RNA levels and secreted protein levels of interleukin 6 and monocyte chemoattractant protein 1 were significantly decreased in empagliflozin-treated adipocytes. Coculture of human induced pluripotent stem cell-derived atrial cardiomyocytes and adipocytes pretreated with or without empagliflozin revealed that empagliflozin significantly suppressed reactive oxygen species. IL6 messenger RNA expression in human EAT showed significant clinically relevant associations. Empagliflozin suppresses human epicardial preadipocyte differentiation/maturation, likely inhibiting epicardial adipogenesis and improving the paracrine secretome profile of EAT, particularly by regulating IL6 expression.

Role of Human Epicardial Adipose Tissue–Derived miR-92a-3p in Myocardial Redox State

BackgroundVisceral obesity is directly linked to increased cardiovascular risk, including heart failure. ObjectivesThis study explored the ability of human epicardial adipose tissue (EAT)-derived microRNAs (miRNAs) to regulate the myocardial redox state and clinical outcomes. MethodsThis study screened for miRNAs expressed and released from human EAT and tested for correlations with the redox state in the adjacent myocardium in paired EAT/atrial biopsy specimens from patients undergoing cardiac surgery. Three miRNAs were then tested for causality in an in vitro model of cardiomyocytes. At a clinical level, causality/directionality were tested using genome-wide association screening, and the underlying mechanisms were explored using human biopsy specimens, as well as overexpression of the candidate miRNAs and their targets in vitro and in vivo using a transgenic mouse model. The final prognostic value of the discovered targets was tested in patients undergoing cardiac surgery, followed up for a median of 8 years. ResultsEAT miR-92a-3p was related to lower oxidative stress in human myocardium, a finding confirmed by using genetic regulators of miR-92a-3p in the human heart and EAT. miR-92a-3p reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase–derived superoxide (O2.–) by targeting myocardial expression of WNT5A, which regulated Rac1-dependent activation of NADPH oxidases. Finally, high miR-92a-3p levels in EAT were independently related with lower risk of adverse cardiovascular events. ConclusionsEAT-derived miRNAs exert paracrine effects on the human heart. Indeed miR-92a-3p suppresses the wingless-type MMTV integration site family, member 5a/Rac1/NADPH oxidase axis and improves the myocardial redox state. EAT-derived miR-92a-3p is related to improved clinical outcomes and is a rational therapeutic target for the prevention and treatment of obesity-related heart disease.

PO-02-175 HUMAN EPICARDIAL ADIPOCYTE-DERIVED SPARCL1 PLAYS AN IMPORTANT ROLE IN SUPPRESSION OF POSTOPERATIVE ATRIAL FIBRILLATION IN PATIENTS UNDERGOING CARDIOVASCULAR SURGERY

Postoperative atrial fibrillation (POAF) occurs in 20-50% after cardiac surgery and exacerbates the short and long-term morbidity/mortality. Potential predisposing factors may exist in the epicardial adipose tissue (EAT) because of its anatomical position. In order to explore a possible mechanistic link, we tried to identify the specific gene expression profile of secretome from the EAT in patients with POAF. We prospectively evaluated 104 patients who underwent scheduled open-heart surgery between May 2020 and May 2022 without known AF (male 69 (66.3%); mean age 68.1 ± 12.3). They are allocated to two groups with (POAF group) or without (no-POAF group) POAF, which is defined as AF lasting over 30 seconds documented by monitor or 12-lead electrocardiogram after the operation. Human EAT samples were obtained from those patients during surgery and preadipocytes were isolated from them. Isolated preadipocytes were terminally differentiated to mature adipocytes and the mRNAs were extracted. Genome-wide expression profiling of 6 vs. 6 matched samples representing POAF or no-POAF group was done using Human Clariom S Assay-HT 16-Array Plate. The secreted protein levels in the adipocytes-cultured medium were also evaluated using enzyme-linked sorbent assay test to confirm the consistency of mRNA expression levels of adipocytes and its secreted protein levels. POAF was observed in 41 patients (39%). Patients in POAF group were significantly older than those in no-POAF group (71.3 ± 9.91 vs 66.0 ± 13.4, p = 0.039). Microarray analysis revealed that there were 132 down- or up-regulated genes (fold change >2.0 or `−2.0, p < 0.05) in epicardial adipocytes of no-POAF group compared to POAF group. Of these genes, 11 genes cording secretable molecules were validated by qPCR, showing that only SPARCL1 had significantly higher expression in no-POAF group than in POAF group (p = 0.039). The mRNA expression of SPARCL1 in adipocytes is significantly correlated with the concentration of SPARCL1 protein in the adipocyte-cultured medium (p < 0.0001, r = 0.9068). Patients aged >75 years had lower mRNA expression of SPARCL1 than patients aged ≤75 years (p = 0.02). Our findings suggested that SPARCL1 expression in human epicardial adipocytes may play an important role in the suppression of POAF in patients undergoing cardiovascular surgery. The expression levels of SPARCL1 are potentially associated with aging.

IDF2022-0574 Oxidative stress in human epicardial versus subcutaneous adipose tissue in heart failure patients

IDF2022-0574 Oxidative stress in human epicardial versus subcutaneous adipose tissue in heart failure patients

Role of epicardial adipose tissue in human atrial fibrillation.

A recent meta-analysis among which four reports were conducted in Japan demonstrated that epicardial adipose tissue (EAT) is closely associated with an increased risk of atrial fibrillation (AF) recurrence after catheter ablation. We previously investigated the role of EAT in AF in humans. Left atrial (LA) appendage samples were obtained from AF patients during cardiovascular surgery. Histologically, the severity of fibrotic EAT remodeling was associated with LA myocardial fibrosis. Total collagen in the LA myocardium (i.e., LA myocardial fibrosis) was positively correlated with proinflammatory and profibrotic cytokines/chemokines, including interleukin-6, monocyte chemoattractant protein-1, and tumor necrosis factor-α, in EAT. Human peri-LA EAT and abdominal subcutaneous adipose tissue (SAT) were obtained by autopsy. EAT- or SAT-derived conditioned medium was applied to the rat LA epicardial surface using an organo-culture system. EAT-conditioned medium induced atrial fibrosis in organo-cultured rat atrium. The profibrotic effect of EAT was greater than that of SAT. The fibrotic area of the organo-cultured rat atrium treated with EAT from patients with AF was greater than in patients without AF. Treatment with human recombinant angiopoietin-like protein 2 (Angptl2) induced fibrosis in organo-cultured rat atrium, which was suppressed by concomitant treatment with anti-Angptl2 antibody. Finally, we attempted to detect fibrotic EAT remodeling on computed tomography (CT) images, which demonstrated that the percent change in EAT fat attenuation was positively correlated with EAT fibrosis. Based on these findings, we conclude that the percent change in EAT fat attenuation determined using CT non-invasively detects EAT remodeling.

Human epicardial adipose tissue expresses glucose-dependent insulinotropic polypeptide, glucagon, and glucagon-like peptide-1 receptors as potential targets of pleiotropic therapies.

Human epicardial adipose tissue (EAT) plays a crucial role in the development and progression of coronary artery disease, atrial fibrillation, and heart failure. Microscopically, EAT is composed of adipocytes, nerve tissues, inflammatory, stromovascular, and immune cells. Epicardial adipose tissue is a white adipose tissue, albeit it also has brown fat-like or beige fat-like features. No muscle fascia divides EAT and myocardium; this allows a direct interaction and crosstalk between the epicardial fat and the myocardium. Thus, it might be a therapeutic target for pharmaceutical compounds acting on G-protein-coupled receptors, such as those for glucose-dependent insulinotropic polypeptide (GIP), glucagon (GCG), and glucagon-like peptide-1 (GLP-1), whose selective stimulation with innovative drugs has demonstrated beneficial cardiovascular effects. The precise mechanism of these novel drugs and their tissue and cellular target(s) need to be better understood. We evaluate whether human EAT expresses GIP, GCG, and GLP-1 receptors and whether their presence is related to EAT transcriptome. We also investigated protein expression and cell-type localization specifically for GIP receptor (GIPR) and glucagon receptor (GCGR). Epicardial adipose tissue samples were collected from 33 patients affected by cardiovascular diseases undergoing open heart surgery (90.9% males, age 67.2 ± 10.5 years mean ± SD). Microarray and immunohistochemistry analyses were performed. Microarray analysis showed that GIPR and GCGR messenger ribonucleic acids (mRNAs) are expressed in EAT, beyond confirming the previously found GLP-1 [3776 ± 1377 arbitrary unit (A.U.), 17.77 ± 14.91 A.U., and 3.41 ± 2.27 A.U., respectively]. The immunohistochemical analysis consistently indicates that GIPR and GCGR are expressed in EAT, mainly in macrophages, isolated, and in crown-like structures. In contrast, only some mature adipocytes of different sizes showed cytoplasmic immunostaining, similar to endothelial cells and pericytes in the capillaries and pre-capillary vascular structures. Notably, EAT GIPR is statistically associated with the low expression of genes involved in free fatty acid (FFA) oxidation and transport and those promoting FFA biosynthesis and adipogenesis (P < 0.01). Epicardial adipose tissue GCGR, in turn, is related to genes involved in FFA transport, mitochondrial fatty acid oxidation, and white-to-brown adipocyte differentiation, in addition to genes involved in the reduction of fatty acid biosynthesis and adipogenesis (P < 0.01). Having reported the expression of the GLP-1 receptor previously, here, we showed that GIPR and GCGR similarly present at mRNA and protein levels in human EAT, particularly in macrophages and partially adipocytes, suggesting these G-protein-coupled receptors as pharmacological targets on the ongoing innovative drugs, which seem cardiometabolically healthy well beyond their effects on glucose and body weight.

Human epicardial adipose tissue inflammation correlates with coronary artery disease.

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. 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+). Novel adipocytokines and inflammatory cells infiltration are dysregulated in human EAT, and could be important pathophysiological mechanisms and novelly promising medicating targets of CAD.

Relationship of omentin-1 with oxidative stress in Iraqi patients with myocardial infraction

A recently recognized adipokine mediator omentin-1 mainly expressed in human epicardial adipose tissue (EAT) has been found to inhibit the inflammatory response and atherosclerosis factors that has potential beneficial effects on cardiovascular disorders. Recent clinical studies reported that the serum omentin-1 levels were negatively related to the severity of Ischemic heart diseases. In this study, we characterized the clinical significance of omentin-1 in myocardial infarction (MI) patients.Investigated its association with oxidative stress, and demonstrated its protective effect as an antioxidant. The study contained 120 subjects who were divided evenly into patients and control groups for the period between September and December 2021. The serum levels of omentin-1 were assessed by enzyme-linked immunosorbent assays methods and serum zinc and copper were measured using atomic absorption spectroscopy. Also, protein oxidation markers and malondialdehyde (MDA) serum levels were measured by spectrophotometer.

Epicardial Adipose Tissue as an Independent Cardiometabolic Risk Factor for Coronary Artery Disease.

During the last decades, visceral adiposity has been at the forefront of scientific research because of its complex role in the pathogenesis of cardiovascular diseases. Epicardial adipose tissue (EAT) is the visceral lipid compartment between the myocardium and the visceral pericardium. Due to their unobstructed anatomic vicinity, epicardial fat and myocardium are nourished by the same microcirculation. It is widely known that EAT serves as an energy lipid source and thermoregulator for the human heart. In addition to this, epicardial fat exerts highly protective effects since it releases a great variety of anti-inflammatory molecules to the adjacent cardiac muscle. Taking into account the unique properties of human EAT, it is undoubtedly a key factor in cardiac physiology since it facilitates complex heart functions. Under pathological circumstances, however, epicardial fat promotes coronary atherosclerosis in a variety of ways. Therefore, the accurate estimation of epicardial fat thickness and volume could be utilized as an early detecting method and future medication target for coronary artery disease (CAD) elimination. Throughout the years, several therapeutic approaches for dysfunctional human EAT have been proposed. A balanced healthy diet, aerobic and anaerobic physical activity, bariatric surgery, and pharmacological treatment with either traditional or novel antidiabetic and antilipidemic drugs are some of the established medical approaches. In the present article, we review the current knowledge regarding the anatomic and physiological characteristics of epicardial fat. In addition to this, we describe the pathogenic mechanisms which refer to the crosstalk between epicardial fat alteration and coronary arterial atherosclerosis development. Lastly, we present both lifestyle and pharmacological methods as possible treatment options for EAT dysfunction.

Potential role of epicardial adipose tissue in coronary artery endothelial cell dysfunction in type 2 diabetes.

Cardiovascular disease is the most prevalent cause of morbidity and mortality in diabetes. Epicardial adipose tissue (EAT) lies in direct contact with the myocardium and coronary arteries and can influence cardiac (patho) physiology through paracrine signaling pathways. This study hypothesized that the proteins released from EAT represent a critical molecular link between the diabetic state and coronary artery endothelial cell dysfunction. To simulate type 2 diabetes-associated metabolic and inflammatory status in an ex vivo tissue culture model, human EAT samples were treated with a cocktail composed of high glucose, high palmitate, and lipopolysaccharide (gplEAT) and were compared with control EAT (conEAT). Compared to conEAT, gplEAT showed a markedly increased gene expression profile of proinflammatory cytokines, corroborating EAT inflammation, a hallmark feature observed in patients with type 2 diabetes. Luminex assay of EAT-secretome identified increased release of various proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), interferon-alpha 2 (IFNA2), interleukin 1 beta (IL1B), interleukin 5 (IL5), interleukin 13 (IL13), and CCL5, among others, in response to high glucose, high palmitate, and lipopolysaccharide. Conditioned culture media was used to collect the concentrated proteins (CPs). In response to gplEAT-CPs, human coronary artery endothelial cells (HCAECs) exhibited an inflammatory endothelial cell phenotype, featuring a significantly increased gene expression of proinflammatory cytokines and cell surface expression of VCAM-1. Moreover, gplEAT-CPs severely decreased Akt-eNOS signaling, nitric oxide production, and angiogenic potential of HCAECs, when compared with conEAT-CPs. These findings indicate that EAT inflammation may play a key role in coronary artery endothelial cell dysfunction in type 2 diabetes.