Abstract 1188: In Vivo Enhancement of Adventitial Neovascularization in Developing Atheroma Using Targeted Echogenic Immunoliposomes
Background: Atheroma growth is associated with increased adventitial neovascularization.
Aim: To evaluate the utility of intravascular ultrasound (IVUS) and targeted echogenic immunoliposomes (ELIP) to demonstrate adventitial neovascularization.
Methods: To create a standard model of atheroma development, Yucatan miniswine (N=4) were prefed with a high cholesterol diet, followed by balloon denudation of the carotid and femoral arteries. After further cholesterol feeding to induce atheroma formation, anti-intercellular adhesion molecule (ICAM) antibody conjugated ELIP were injected and the arteries imaged with IVUS. Images were digitized and the arterial walls segmented. Adventitial boundaries were determined using previous validated methodologies. Highlighted adventitia was determined using mean gray scale values (MGSV). Three-dimensional reconstruction of a series of IVUS images was performed to better demonstrate highlighted adventitia.
Results: Anti-ICAM-ELIP demonstrated adventitial highlighting throughout the segments with atheroma (Figure⇓). This highlighting persisted for at least 30 minutes. Adventitial MGSV was 115±23.0 (anti-ICAM-ELIP treated) vs. 84±22.2 (baseline), p<0.05.
Conclusion: We have successfully demonstrated the feasibility of anti-ICAM-ELIP in enhancing adventitial neovascularization and its spatial distribution in developing atherosclerosis. This extends the utility of IVUS to image outside of the arterial media and to provide targeted molecular imaging of active components in atheroma development.