Human epicardial adipose tissue is a source of inflammatory mediators.
BACKGROUND
Inflammatory mediators that originate in vascular and extravascular tissues promote coronary lesion formation. Adipose tissue may function as an endocrine organ that contributes to an inflammatory burden in patients at risk of cardiovascular complications. In this study, we sought to compare expression of inflammatory mediators in epicardial and subcutaneous adipose stores in patients with critical CAD.


RESULTS
Paired samples of epicardial and subcutaneous adipose tissues were harvested at the outset of elective CABG surgery (n=42; age 65+/-10 years). Local expression of chemokine (monocyte chemotactic protein [MCP]-1) and inflammatory cytokines (interleukin [IL]-1beta, IL-6, and tumor necrosis factor [TNF]-alpha) was analyzed by TaqMan real-time reverse transcription-polymerase chain reaction (mRNA) and by ELISA (protein release over 3 hours). Significantly higher levels of IL-1beta, IL-6, MCP-1, and TNF-alpha mRNA and protein were observed in epicardial adipose stores. Proinflammatory properties of epicardial adipose tissue were noted irrespective of clinical variables (diabetes, body mass index, and chronic use of statins or ACE inhibitors/angiotensin II receptor blockers) or plasma concentrations of circulating biomarkers. In a subset of samples (n=11), global gene expression was explored by DNA microarray hybridization and confirmed the presence of a broad inflammatory reaction in epicardial adipose tissue in patients with coronary artery disease. The above findings were paralleled by the presence of inflammatory cell infiltrates in epicardial adipose stores.


CONCLUSIONS
Epicardial adipose tissue is a source of several inflammatory mediators in high-risk cardiac patients. Plasma inflammatory biomarkers may not adequately reflect local tissue inflammation. Current therapies do not appear to eliminate local inflammatory signals in epicardial adipose tissue.
Department of Surgery, Thomas Jefferson University, Suite 623, 1025 Walnut St, Philadelphia, Pa 19107, USA.
Tomasz
T
Mazurek
LiFeng
L
Zhang
Andrew
A
Zalewski
John D
JD
Mannion
James T
JT
Diehl
Hwyda
H
Arafat
Lea
L
Sarov-Blat
Shawn
S
O'Brien
Elizabeth A
EA
Keiper
Anthony G
AG
Johnson
Jack
J
Martin
Barry J
BJ
Goldstein
Yi
Y
Shi
D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D018932:Chemokine CCL2 / Q000097:blood / Q000378:metabolism; D016000:Cluster Analysis; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism*; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood / Q000378:metabolism; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D010496:Pericardium / Q000378:metabolism* / Q000473:pathology; D019947:Receptors, Interleukin-6 / Q000097:blood / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism
D015415:Biomarkers; D018932:Chemokine CCL2; D018836:Inflammation Mediators; D007375:Interleukin-1; D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D014409:Tumor Necrosis Factor-alpha