Abstract 18570: Real-Time in vivo Imaging of Reactive Oxygen Species (ROS) Dynamics in Murine Carotid Atheroma Using Novel ROS-Responsive NIRF Emitting Sensor
Introduction and Hypothesis: Excessive oxidative stress with reactive oxygen species (ROS) has been implicated in the pathogenesis of atherosclerosis, but only few studies have ever imaged ROS in atherosclerotic plaques. We aimed to develop a novel ROS-responsive NIRF emitting sensor and test whether it can detect ROS in vitro and image intraplaque ROS in vivo using a customized intravital imaging.
Methods and Results: A novel ROS-responsive sensor was fabricated by conjugating Chlorin e6 (Ce6, ex/em 660/675nm) to hyaluronic acid through a ROS-degradable thioketal linker. After exposure to various ROS in vitro, the thioketal linker of the quenched sensor was degraded by ROS (i.e., ·OH > O2- > OCl-) and a near infrared fluorescence (NIRF) signal recovery was observed due to dequenching of the Ce6. To further assess intraplaque ROS in vivo, at 48 hrs after iv injection of the ROS sensor (2.5 mg/kg of Ce6), we imaged right carotid atheroma of atherogenic mice (apoE -/-, high cholesterol diet (HCD) for 4months) using our customized multispectral intravital fluorescence microscope (IVFM) under mechanical carotid stabilization. The ROS induced NIRF signals in the plaques were strongly detected as compared to normal vessels (Figure, p<0.01), and significantly attenuated in N-acetylcysteine (NAC)-treated mice (apoE -/-. HCD for 4 month, NAC 200mg/kg for 2 months)(p<0.01). In vitro data, fluorescence microscope and immunohistologic analysis in sister sections of the target plaques corroborated the in vivo findings.
Conclusions: Our ROS sensor was feasible to detect intraplaque ROS activity in vivo. This novel ROS imaging strategy is expected to estimate the dynamic relationship of ROS generation and atherogenesis in vivo.
Author Disclosures: E. Park: None. C. Kim: None. J. Kim: None. B. Yi: None. J. Song: None. H. Kim: None. J. Jeon: None. D. Oh: None. H. Yoo: None. K. Park: None. J. Kim: None.
- © 2016 by American Heart Association, Inc.