Molecular imaging of vasa vasorum neovascularization via DEspR-targeted contrast-enhanced ultrasound micro-imaging in transgenic atherosclerosis rat model.
OBJECTIVE
Given that carotid vasa vasorum neovascularization is associated with increased risk for stroke and cardiac events, the present in vivo study was designed to investigate molecular imaging of carotid artery vasa vasorum neovascularization via target-specific contrast-enhanced ultrasound (CEU) micro-imaging.


METHODS
Molecular imaging was performed in male transgenic rats with carotid artery disease and non-transgenic controls using dual endothelin1/VEGFsp receptor (DEspR)-targeted microbubbles (MB(D)) and the Vevo770 micro-imaging system and CEU imaging software.


RESULTS
DEspR-targeted CEU-positive imaging exhibited significantly higher contrast intensity signal (CIS)-levels and pre-/post-destruction CIS-differences in seven of 13 transgenic rats, in contrast to significantly lower CIS-levels and differences in control isotype-targeted microbubble (MB(C))-CEU imaging (n = 8) and in MB(D) CEU-imaging of five non-transgenic control rats (P < 0.0001). Ex vivo immunofluorescence analysis demonstrated binding of MB(D) to DEspR-positive endothelial cells; and association of DEspR-targeted increased contrast intensity signals with DEspR expression in vasa vasorum neovessel and intimal lesions. In vitro analysis demonstrated dose-dependent binding of MB(D) to DEspR-positive human endothelial cells with increasing %cells bound and number of MB(D) per cell, in contrast to MB(C) or non-labeled microbubbles (P < 0.0001).


CONCLUSIONS
In vivo DEspR-targeted molecular imaging detected increased DEspR-expression in carotid artery lesions and in expanded vasa vasorum neovessels in transgenic rats with carotid artery disease. Future studies are needed to determine predictive value for stroke or heart disease in this transgenic atherosclerosis rat model and translational applications.
Whitaker Cardiovascular Institute, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
Julius L
JL
Decano
Anne Marie
AM
Moran
Nelson
N
Ruiz-Opazo
Victoria L M
VL
Herrera
D000818:Animals; D050197:Atherosclerosis / Q000000981:diagnostic imaging*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D003287:Contrast Media; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000473:pathology; D005455:Fluorescent Antibody Technique; D006801:Humans; D045423:Microbubbles; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D057054:Molecular Imaging / Q000379:methods*; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging*; D051381:Rats; D055647:Rats, Transgenic; D044022:Receptor, Endothelin A / Q000378:metabolism*; D017466:Receptors, Endothelin / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism*; D014463:Ultrasonography; D014651:Vasa Vasorum / Q000000981:diagnostic imaging / Q000473:pathology*
D003287:Contrast Media; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin; C570659:dear protein, rat; D040262:Receptors, Vascular Endothelial Growth Factor