Comparison of a New 68 Ga-Radiolabelled PET Imaging Agent sCD146 and RGD Peptide for In Vivo Evaluation of Angiogenesis in Mouse Model of Myocardial Infarction.

Ischemic vascular diseases are associated with elevated tissue expression of angiomotin (AMOT), a promising molecular target for PET imaging. On that basis, we developed an AMOT-targeting radiotracer, ⁶⁸ Ga-sCD146 and performed the first in vivo evaluation on a myocardial infarction mice model and then, compared AMOT expression and α _v β ₃ -integrin expression with ⁶⁸ Ga-sCD146 and ⁶⁸ Ga-RGD ₂ imaging. After myocardial infarction (MI) induced by permanent ligation of the left anterior descending coronary artery, myocardial perfusion was evaluated by Doppler ultrasound and by ¹⁸ F-FDG PET imaging. ⁶⁸ Ga-sCD146 and ⁶⁸ Ga-RGD ₂ PET imaging were performed. In myocardial infarction model, heart-to-muscle ratio of ⁶⁸ Ga-sCD146 imaging showed a significantly higher radiotracer uptake in the infarcted area of MI animals than in sham (* p = 0.04). Interestingly, we also observed significant correlations between ⁶⁸ Ga-sCD146 imaging and delayed residual perfusion assessed by ¹⁸ F-FDG (* p = 0.04), with lowest tissue fibrosis assessed by histological staining (* p = 0.04) and with functional recovery assessed by ultrasound imaging (** p = 0.01). ⁶⁸ Ga-sCD146 demonstrated an increase in AMOT expression after MI. Altogether, significant correlations of early post-ischemic ⁶⁸ Ga-sCD146 uptake with late heart perfusion, lower tissue fibrosis and better functional recovery, make ⁶⁸ Ga-sCD146 a promising radiotracer for tissue angiogenesis assessment after MI.