Epicardial Fat in Cardiovascular Diseases

• EAT thermoregulatory genes[ Time Frame: 24 hours ]
  Differences in peri-coronary EAT thermoregulatory transcriptome in patients with and without CAD

Epicardial adipose tissue (EAT) is the visceral fat depot of the heart. EAT transcriptome is unique when compared to subcutaneous fat. EAT is a highly inflammatory tissue enriched with genes involved in inflammation, endothelial function, immune signaling and thermoregulation. EAT has been correlated with coronary artery disease (CAD) and atrial fibrillation (AF), although the mechanisms of the interplay of EAT with these two major cardiovascular diseases have not been fully understood. Whether EAT may act as brown fat and whether this may be affected by the presence of CAD is currently unknown. Whether the postulated thermoregulatory function of the EAT is correlated to the presence and severity of CAD is unknown EAT is though to play a role in the development and recurrence of AF. Recent studies showed that EAT has a unique transcriptome with genes encoding for pro-arrhythmogenic proteins. EAT is located in different areas of the heart. Whether regional EAT depots may have different genetic profile and functions is unknown. Whether peri-atrial EAT may have unique effects on cardiac muscle activity distinct from other EAT sub-depots is unknown. Peri left atrial EAT and pericoronary EAT will be collected from patients who are undergoing elective cardiac surgery as standard care. EAT transcriptome will be analysed with RNA- sequencing analysis (RNA-seq) and quantitative real time polymerase chain reaction (qRT-PCR) . Immunofluorescence and immunoblot will be also performed on fat samples.

• Procedure: Coronary artery bypass grafting (CABG)
  CABG, as part of the standard medical care
• Procedure: Valve replacement
  cardiac surgery for aortic or mitral valve replacement as part of their standard medical care

• : AF + CAD
  Patients with clinically and angiographically established CAD and Atrial Fibrillation (AF) who require CABG, as part of the standard medical care
• : (no AF + CAD)
  Patients with clinically and angiographically established CAD without AF who require CABG, as part of the standard medical care
• : Control (no CAD, no AF)
  subjects who have no history, clinical signs of either CAD or AF, randomly selected, who will undergo cardiac surgery for aortic or mitral valve replacement as part of their standard medical care