Interleukin-15 and soluble interleukin-15 receptor α in coronary artery disease patients: association with epicardial fat and indices of adipose tissue distribution

PLoS One. 2014 Mar 6;9(3):e90960. doi: 10.1371/journal.pone.0090960. eCollection 2014.

Abstract

Interleukin-15 (IL-15) is a pro-inflammatory cytokine which signals via a specific alpha receptor subunit (IL-15Rα). Increased IL-15 level has been observed in cardiovascular patients and IL-15 immunoreactivity has been detected at vulnerable atherosclerotic plaques. Due to the association between adipose tissue distribution, inflammation and coronary artery disease (CAD), we quantified IL-15 and IL-15Rα in CAD patients with different adiposity and adipose tissue distribution and we evaluated whether epicardial adipose tissue (EAT), a visceral fat depot surrounding and infiltrating myocardium, may be a source of both molecules. IL-15 and IL-15Rα proteins were quantified by enzyme-linked immunosorbent assays. Gene expression of IL-15 and IL-15Rα in EAT depots was evaluated by one colour microarray platform. EAT thickness was measured by echocardiography. Plasmatic IL-15 and IL-15Rα levels were higher in CAD than non-CAD patients. After classification according to adipose tissue distribution, IL-15 was higher in CAD patients with increased abdominal adiposity. Increased level of IL-15Rα was observed both in CAD and non-CAD patients with increased abdominal fat. EAT was a source of IL-15 and IL-15Rα and their expression was higher in CAD patients with increased EAT thickness. In conclusion, our data suggest that circulating levels of IL-15 and IL-15Rα seem to reflect visceral distribution of adipose tissue and that EAT may be a potential source of both IL-15 and IL-15Rα. Future studies on the relationship between IL-15, visceral fat and characteristics of atherosclerotic plaques could help to better understand the complex biology of this cytokine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adiposity / genetics
  • Aged
  • Aged, 80 and over
  • Body Fat Distribution
  • Coronary Artery Disease / blood*
  • Coronary Artery Disease / genetics
  • Coronary Artery Disease / pathology
  • Coronary Vessels / metabolism
  • Coronary Vessels / pathology
  • Female
  • Gene Expression
  • Humans
  • Interleukin-15 / blood*
  • Interleukin-15 / genetics
  • Interleukin-15 Receptor alpha Subunit / blood*
  • Interleukin-15 Receptor alpha Subunit / genetics
  • Intra-Abdominal Fat / metabolism*
  • Intra-Abdominal Fat / pathology
  • Male
  • Middle Aged
  • Pericardium / metabolism*
  • Pericardium / pathology
  • Plaque, Atherosclerotic / blood*
  • Plaque, Atherosclerotic / genetics
  • Plaque, Atherosclerotic / pathology
  • Signal Transduction

Substances

  • IL15 protein, human
  • Interleukin-15
  • Interleukin-15 Receptor alpha Subunit

Grants and funding

The study was supported by funds from Italian Ministry for Health “Ricerca Corrente” I.R.C.C.S. Policlinico San Donato, internal funds from University of Regensburg and the EU Framework/project ‘LipidomicNet’. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.