Genesis of epicardial adipocytes and its association with progenitor markers, muscarinic receptor type 3 and b-blockers intake in patients with cardiovascular disease

Introduction

Epicardial fat thickness or volume was found to be associated with cardiovascular disease (CVD). Our aim was to study the epicardial adipocyte-progenitors' markers and its association with cholinergic or adrenergic activity in patients with cardiovascular disease.

Materials and methods

We have included epicardial adipose tissue (EAT) biopsies from 29 patients underwent open-heart surgery. From 10 patients (69±5 years old, 31±8 kg/ m2, 40% CAD, 40% HF, 60% AF, 0% T2DM) stromal cells from epicardial and subcutaneous fat were isolated after collagenase activity and cultured for 14 days and then submitted to adipogenesis for next 14 days. Samples from 19 patients (60±9 years old, 29±4 kg/m2, 42% CAD, 37% HF, 32% AF, 32% T2DM, 53% β-blockers) were used for “ex vivo assays”. Explants were split into equal pieces (100 mg), treated with or without acetylcholine (ACh) for 30 min. Afterwards RNA was isolated and cDNA was amplified by real time PCR. We selected adipocytes progenitors (CD36, PREF1, COL1A1), adipocytes markers (ADIPO, FABP4), muscarinic (muscarinic receptor type 2 (CHRM2) and 3 (CHRM2)) and β-adrenergic receptors (ABRD1, ABRD2 and ABRD3). Gene expression was represented regarding ACTB as 2HK/GEN.

Results

The stromal vascular cells (SVC) from subcutaneous fat (SAT) had higher expression levels of CD36, PREF1 and COL1A1 than SVC from epicardial fat (EAT). It explains the higher adipocytes markers after adipogenesis induction in SAT than EAT cells. However, an upregulation of fibroblasts markers was detected on EAT. The levels of CD36 and PREF1 in SVC were associated with higher adipogenesis. Although CHRM2 was higher in EAT than SAT SVC, the adipogenesis induction upregulated only CHRM3 (1.48±0.065 vs 1.42±0.036 a.u.) in EAT cells. Thus, this receptor was associated with adipocytes markers in epicardial fat (r=0.777 for CD36 and r=0.746 for FABP4) and incremented in epicardial fat biopsies from patients who were taken β-blockers (1.61±0.011 n=10 vs 1.54±0.097 a.u. n=9; p=0.05) and modulated by ACh treatment (p=0.05).

Conclusions

Our results showed that CD36 and PREF1 in epicardial SVC are adipocytes progenitors. The higher presence of adipocytes markers is associated with higher levels of muscarinic receptor (CHRM3), which are upregulated in epicardial fat from patients who were taken β-blockers and modulated by cholinergic activity. Because a metabolic and lipolytic dysfunction was associated with CHRM3, the sympathetic modulation might play a role in the epicardial adipocytes genesis. Further studies are needed to understand if this mechanism might improve or not future cardiovascular events.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ISCIII (PFIS2020)

CD5L, Macrophage Apoptosis Inhibitor, Was Identified in Epicardial Fat-Secretome and Regulated by Isoproterenol From Patients With Heart Failure

Objectives

Neurohormonal dysfunction, which can regulate epicardial fat activity, is one of the main promoters of atrial fibrillation (AF) in patients with heart failure (HF). Our aim was to study the epicardial fat mediators for AF in patients with HF and its catecholaminergic regulation.

Methods

We have included 29 patients with HF who underwent cardiac surgery and were followed up for 5 years. Released proteins by epicardial adipose tissue (EAT) after isoproterenol treatment were identified by nano-high-performance liquid chromatography (HPLC) and triple time-of-flight (TOF) analysis. Common and differential identified proteins in groups of patients with AF before and after surgery were determined by the FunRich tool. Plasma and epicardial fat biopsy proteins were quantified by western blot.

Results

Our results identified 17 common released proteins by EAT, after isoproterenol treatment, from HF patients who suffered AF or developed new-onset AF during follow-up. Mostly, they were involved on inflammatory response and extracellular matrix. One of them was CD5L, a macrophage apoptosis inhibitor. Its secretion by isoproterenol treatment was validated on western blot. The CD5L levels on epicardial fat were also higher in the group of male patients who present or develop AF (0.44 ± 0.05 vs. 0.18 ± 0.15; p < 0.016). However, there were no differences regarding plasma levels.

Conclusion

Our results suggest the role of epicardial fat CD5L as a mediator of AF and its possible paracrine effect by catecholaminergic activity.

P3494Dapagliflozin reduced lactate release by epicardial adipose tissue from CAD patients: switch from fatty acids to glucose aerobic oxidation

Background

Dapagliflozin, a sodium-glucose co-transporter 2 inhibitor, improves the glucose uptake by epicardial adipose tissue (EAT). However, its metabolic pathways are still unknown. Our aim was to clarify the EAT glucose-lipid metabolism from patients with and without coronary artery disease (CAD).

Methods

Paired subcutaneous (SAT) and EAT biopsies from 49 patients undergoing heart surgery were cultured and treated with or without dapa at 10 or 100 μM for 6 hours. Glucose, lactate and oxygen were analyzed on supernatants by colorimetric or fluorescence assays. Glycolytic, lipolytic, glyceroneogenic and lipogenic genes or protein expression levels were determined on fat tissues by RT-qPCR or western blot, respectively.

Results

Glyceroneogenic and lipid metabolism-involved genes were higher expressed in SAT than in EAT. Dapa reduced their expression in SAT but not in EAT. Lipid-droplet protein levels, perilipin (PLN A) and hormone-sensitive lipase (HSL), were reduced in EAT. Mitochondrial biogenesis-related gene PGC1α was upregulated (p<0.05). Despite this drug improved glucose utilization, it reduced lactate release and oxygen consumption in both fat pads. After classifying patients according presence/absence of CAD, we observed a greater release of lactate by EAT in patients with CAD (3.22±2.40 mM) that was remarkably reduced after dapagliflozin treatment at 10 μM (2.17±1.53 mM, p<0.01) and 100 μM (2.45±2.11 mM, p<0.001).

Clinical characteristics regarding CAD presence (n=49) Non CAD patients (n=26) CAD patients (n=23) p value Gender (male) (n/%) 14/54 20/87 0.010* Age (years) 73±9 67±12 0.026* BMI (kg/m2) 29.±4 30±4 0.377 HTA (n/%) 21/80.8 17/73.9 0.578 T2DM (n/%) 12/46 9/39 0.629 HF (n/%) 2/8 6/26 0.096 L-Lactate (mM) 2±1.1 3.2±2.4 0.029* Glucose (mg/dL) 65±15 62±22 0.539 Oxygen (RFU) 47±9 46±14 0.899 CAD: Coronary artery disease, BMI: Body mass index, HTA: arterial hypertension, T2DM: Diabetes mellitus type 2, HF: Heart failure, RFU: relative fluorescence units.

Lactate in CAD

Conclusions

Dapagliflozin reduced the anaerobic glycolytic pathway, lowering the released lactate by EAT, overall in patients with CAD. This effect suggests a protective metabolic role since high lactate was found to be a marker of poor outcomes in HF patients.

Acknowledgement/Funding

Astrazeneca