title: Combined two-photon luminescence microscopy and OCT for macrophage detection in the hypercholesterolemic rabbit aorta using plasmonic gold nanorose.
abstract: OBJECTIVE
  The macrophage is an important early cellular marker related to risk of future rupture of atherosclerotic plaques. Two-channel two-photon luminescence (TPL) microscopy combined with optical coherence tomography (OCT) was used to detect, and further characterize the distribution of aorta-based macrophages using plasmonic gold nanorose as an imaging contrast agent.
  
  
  METHODS
  Nanorose uptake by macrophages was identified by TPL microscopy in macrophage cell culture. Ex vivo aorta segments (8 × 8 × 2 mm(3) ) rich in macrophages from a rabbit model of aorta inflammation were imaged by TPL microscopy in combination with OCT. Aorta histological sections (5 µm in thickness) were also imaged by TPL microscopy.
  
  
  RESULTS
  Merged two-channel TPL images showed the lateral and depth distribution of nanorose-loaded macrophages (confirmed by RAM-11 stain) and other aorta components (e.g., elastin fiber and lipid droplet), suggesting that nanorose-loaded macrophages are diffusively distributed and mostly detected superficially within 20 µm from the luminal surface of the aorta. Moreover, OCT images depicted detailed surface structure of the diseased aorta.
  
  
  CONCLUSIONS
  Results suggest that TPL microscopy combined with OCT can simultaneously reveal macrophage distribution with respect to aorta surface structure, which has the potential to detect vulnerable plaques and monitor plaque-based macrophages overtime during cardiovascular interventions.
authors.affiliation: Department of Biomedical Engineering, University of Texas at Austin, 1 University Station C0800, Austin, Texas 78712, USA.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Wang
authors.forename: J Jacob
authors.initials: JJ
authors.lastname: Mancuso
authors.forename: S M Shams
authors.initials: SM
authors.lastname: Kazmi
authors.forename: Jordan
authors.initials: J
authors.lastname: Dwelle
authors.forename: Veronika
authors.initials: V
authors.lastname: Sapozhnikova
authors.forename: Brian
authors.initials: B
authors.lastname: Willsey
authors.forename: Li L
authors.initials: LL
authors.lastname: Ma
authors.forename: Jinze
authors.initials: J
authors.lastname: Qiu
authors.forename: Xiankai
authors.initials: X
authors.lastname: Li
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Dunn
authors.forename: Keith P
authors.initials: KP
authors.lastname: Johnston
authors.forename: Marc D
authors.initials: MD
authors.lastname: Feldman
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Milner
mesh_terms: D000818:Animals; D001158:Arteries / Q000166:cytology; D050197:Atherosclerosis / Q000473:pathology*; D001707:Biopsy, Needle; D002478:Cells, Cultured; D003287:Contrast Media / Q000032:analysis*; D004195:Disease Models, Animal; D006046:Gold / Q000032:analysis; D006937:Hypercholesterolemia / Q000473:pathology*; D007089:Image Enhancement / Q000379:methods; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D049449:Luminescence; D008264:Macrophages / Q000473:pathology*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D049329:Nanostructures / Q000032:analysis*; D011817:Rabbits; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence
chemical_list: D003287:Contrast Media; D006046:Gold