title: In vivo high-resolution structural imaging of large arteries in small rodents using two-photon laser scanning microscopy.
abstract: In vivo (molecular) imaging of the vessel wall of large arteries at subcellular resolution is crucial for unraveling vascular pathophysiology. We previously showed the applicability of two-photon laser scanning microscopy (TPLSM) in mounted arteries ex vivo. However, in vivo TPLSM has thus far suffered from in-frame and between-frame motion artifacts due to arterial movement with cardiac and respiratory activity. Now, motion artifacts are suppressed by accelerated image acquisition triggered on cardiac and respiratory activity. In vivo TPLSM is performed on rat renal and mouse carotid arteries, both surgically exposed and labeled fluorescently (cell nuclei, elastin, and collagen). The use of short acquisition times consistently limit in-frame motion artifacts. Additionally, triggered imaging reduces between-frame artifacts. Indeed, structures in the vessel wall (cell nuclei, elastic laminae) can be imaged at subcellular resolution. In mechanically damaged carotid arteries, even the subendothelial collagen sheet (approximately 1 microm) is visualized using collagen-targeted quantum dots. We demonstrate stable in vivo imaging of large arteries at subcellular resolution using TPLSM triggered on cardiac and respiratory cycles. This creates great opportunities for studying (diseased) arteries in vivo or immediate validation of in vivo molecular imaging techniques such as magnetic resonance imaging (MRI), ultrasound, and positron emission tomography (PET).
authors.affiliation: Maastricht University, Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Remco T A
authors.initials: RT
authors.lastname: Megens
authors.forename: Sietze
authors.initials: S
authors.lastname: Reitsma
authors.forename: Lenneke
authors.initials: L
authors.lastname: Prinzen
authors.forename: Mirjam G A
authors.initials: MG
authors.lastname: oude Egbrink
authors.forename: Wim
authors.initials: W
authors.lastname: Engels
authors.forename: Peter J A
authors.initials: PJ
authors.lastname: Leenders
authors.forename: Ellen J L
authors.initials: EJ
authors.lastname: Brunenberg
authors.forename: Koen D
authors.initials: KD
authors.lastname: Reesink
authors.forename: Ben J A
authors.initials: BJ
authors.lastname: Janssen
authors.forename: Bart M
authors.initials: BM
authors.lastname: ter Haar Romeny
authors.forename: Dick W
authors.initials: DW
authors.lastname: Slaaf
authors.forename: Marc A M J
authors.initials: MA
authors.lastname: van Zandvoort
mesh_terms: D000818:Animals; D017536:Carotid Artery, Common / Q000033:anatomy & histology*; D003094:Collagen / Q000032:analysis / Q000737:chemistry; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000379:methods*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D009068:Movement / Q000502:physiology; D051381:Rats; D012077:Renal Artery / Q000033:anatomy & histology*
chemical_list: D003094:Collagen