Abstract 11698: Myocardial Scar Imaging With Collagen-targeting Gold Nanoparticles

Abstract

Background: In the setting of myocardial ischemia, recovery of myocardial function by revascularization procedures depends on the extent of coronary disease and myocardial scar burden. Currently, computed tomographic (CT) imaging offers superior evaluation of coronary lesions but lacks the capability to detect the transmural extent of myocardial scar. The objectives of this study are to determine if collagen-targeting gold nanotracers can effectively target myocardial scar and provide contrast for CT imaging.

Methods: Gold nanoparticles (AuNPs) were coated with a collagen-homing peptide, collagen adhesin (CNA35). Myocardial scar was created in mice by occlusion/ reperfusion of the left anterior descending coronary artery. Thirty days after the injury, un-gated CT imaging was performed with a GE Ultra flat panel CT scanner. The heart was harvested at 6h after AuNPs injection. Picrosirius Red and silver staining were performed to evaluate the extent of collagen deposition and retention of CNA35-AuNPs in the myocardium.

Results: Over 6h, CNA35-AuNPs provided uniform and prolonged opacification of the vascular structures (100-150 HU). In mice with larger scar burden, focal contrast enhancement was detected in the myocardium, which was not apparent within that of control mice and mice with smaller scar burden. Picrosirius Red staining confirmed a range of sizes of myocardial scar formation, which correlated with the amount of silver enhancement - a surrogate marker of AuNPs retention. In control mice, there was no evidence of collagen deposition or silver enhancement within the myocardium.

Conclusions: This study demonstrated the feasibility of using CNA35 AuNPs for vascular imaging and specific collagen targeting in the myocardial scar. This combined use of a nanomaterial with higher attenuation than traditional CT contrast agents and specific targeting mechanism for myocardial scar burden may expand the applications of cardiovascular CT imaging.