Journal
CIRCULATION
Volume 115, Issue 17, Pages 2292-2298Publisher
LIPPINCOTT WILLIAMS & WILKINS
DOI: 10.1161/CIRCULATIONAHA.106.660340
Keywords
atherosclerosis; cathepsin K; fluorescence; imaging; inflammation
Funding
- NCI NIH HHS [P50-CA86355, R24-CA92782] Funding Source: Medline
- NHLBI NIH HHS [U01 HL080731, R01-HL080472] Funding Source: Medline
Ask authors/readers for more resources
Background - Cathepsin K (CatK), a potent elastinolytic and collagenolytic cysteine protease, likely participates in the evolution and destabilization of atherosclerotic plaques. To assess better the biology of CatK activity in vivo, we developed a novel near-infrared fluorescence (NIRF) probe for imaging of CatK and evaluated it in mouse and human atherosclerosis. Methods and Results - The NIRF imaging agent consists of the CatK peptide substrate GHPGGPQGKC-NH2 linked to an activatable fluorogenic polymer. In vitro, CatK produced a 2- to 14-fold activation of the agent over other cysteine and matrix metalloproteinases ( P < 0.0001), as well as a > 8-fold activation over a control imaging agent ( P < 0.001). Optical imaging of atheroma revealed > 100% NIRF signal increases in apolipoprotein E-/- mice in vivo (n = 13; P < 0.05, CatK imaging agent versus control agent) and in human carotid endarterectomy specimens ex vivo ( n = 14; P < 0.05). Fluorescence microscopy of plaque sections demonstrated that enzymatically active CatK ( positive NIRF signal) localized primarily in the vicinity of CatK-positive macrophages. Augmented NIRF signal ( reflecting CatK activity) colocalized with disrupted elastin fibers within the media underlying plaques. Conclusions - Use of this novel protease-activatable NIRF agent for optical imaging in vivo demonstrated preferential localization of enzymatically active CatK to macrophages, consistent with their known greater elastinolytic capabilities compared with smooth muscle cells. Augmented CatK proteolysis in atheromata further links CatK to vascular remodeling and plaque vulnerability.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available