Abstract 13801: Increased Pericardial Adipose Tissue Volume and its Association With Adverse Left Ventricular Remodeling: Does MiR-208a Release Into the Pericardial Space Provide a Mechanistic Link?
Background: There are no data on the potential role of Pericardial adipose tissue (PAT) on left ventricular remodeling in patients after acute myocardial infarction (AMI). Therefore, we measured PAT volume by serial cardiac MRI after AMI, and determined its relation to cardiac function. Furthermore, we measured the concentrations of specific Micro-RNAs (miRs) in adipose-tissue samples obtained from patients with or without myocardial ischemia.
Methods: PAT volume and parameters of LV-function were analyzed in 109 patients by serial cardiac MRI 4 to 7 days after AMI as well as after 4 months. In addition, in a total of 35 patients, we collected adipose tissue samples from the pericardial fat, from the mediastinal fat as well as from peripheral fat during cardiac surgery for acute- or non-acute bypass grafting (CABG) or cardiac valvular surgery as a control group. Tissue concentrations of the myocardial-specific miR-208a were measured by PCR.
Results: At baseline early after AMI, left ventricular ejection fraction (LVEF) was modestly reduced (mean: 47.3 ± 10.5 %) and PAT volume was 181±74 cm3. There was no correlation between PAT volume at baseline and initial LVEF. At 4 months, LVEF improved to 53.2 ± 12.7% and PAT volume was significantly reduced (mean: 168 ± 69 cm3; p<0.0001) for the entire study cohort. Importantly, patients with evidence of “adverse LV remodeling” after AMI as measured by increased LVESVI at 4 months (n=37) had a significantly (p=0.008) greater PAT volume at 4 months compared to patients without adverse remodeling, indicating that the adversely remodeling heart may signal to the pericardial fat tissue. Within the cardiac surgery cohort, concentrations of the myocardium-specific miR-208a were profoundly and significantly (p=0.006) elevated in the pericardial adipose tissue of patients undergoing CABG during acute myocardial ischemia in comparison to the cardiac valvular surgery control group.
Conclusion: Adverse left ventricular remodeling post-AMI is associated with a significant increase in PAT volume. Given that miR-208a targets nuclear hormone receptors involved in adipogenesis, the release of myocardial miR-208a into the pericardium during ischemia may link adverse remodeling of the myocardium with an increase in PAT.
- © 2013 by American Heart Association, Inc.