In vivo detection of macrophages in a rabbit atherosclerotic model by time-resolved laser-induced fluorescence spectroscopy

Laura Marcu, Qiyin Fang, Javier A. Jo, Thanassis Papaioannou, Amir Dorafshar, Todd Reil, Jian Hua Qiao, J. Dennis Baker, Julie A. Freischlag, Michael C. Fishbein

Research output: Contribution to journalArticle

61 Scopus citations

Abstract

Accumulation of numerous macrophages in the fibrous cap is a key identifying feature of plaque inflammation and vulnerability. This study investigates the use of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) as a potential tool for detection of macrophage foam cells in the intima of atherosclerotic plaques. Experiments were conducted in vivo on 14 New Zealand rabbits (6 control, 8 hypercholesterolemic) following aortotomy to expose the intimal luminal surface of the aorta. Tissue autofluorescence was induced with a nitrogen pulse laser (337 nm, 1 ns). Lesions were histologically classified by the percent of collagen or macrophage foam cells as well as thickness of the intima. Using parameters derived from the time-resolved fluorescence emission of plaques, we determined that intima rich in macrophage foam cells can be distinguished from intima rich in collagen with high sensitivity (>85%) and specificity (>95%). This study demonstrates, for the first time, that a time-resolved fluorescence-based technique can differentiate and demark macrophage content versus collagen content in vivo. Our results suggest that TR-LIFS technique can be used in clinical applications for identification of inflammatory cells important in plaque formation and rupture.

Original languageEnglish (US)
Pages (from-to)295-303
Number of pages9
JournalAtherosclerosis
Volume181
Issue number2
DOIs
StatePublished - Aug 2005

Keywords

  • Atherosclerotic diagnosis
  • Time-resolved fluorescence spectroscopy
  • Vulnerable plaques

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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    Marcu, L., Fang, Q., Jo, J. A., Papaioannou, T., Dorafshar, A., Reil, T., Qiao, J. H., Baker, J. D., Freischlag, J. A., & Fishbein, M. C. (2005). In vivo detection of macrophages in a rabbit atherosclerotic model by time-resolved laser-induced fluorescence spectroscopy. Atherosclerosis, 181(2), 295-303. https://doi.org/10.1016/j.atherosclerosis.2005.02.010