Astudy of 68Ga-FAPIin the imaging of atherosclerosis in New Zealand rabbits

1233 Background: Positron emission tomography is a non-invasive examination to monitoring biological procedures of tumors and cardiovascular events in body form the molecular aspect. Cardiovascular disease is the leading cause of much morbidity and mortality worldwide. Atherosclerosis is getting more concerns attribute to the initiate ability in cardiovascular diseases. Atherosclerosis is a chronic inflammatory disease that simultaneously accompanied with fibrofatty lesions, calcification and rupture. Fibroblast activation protein (FAP) plays an important role in many solid tumors and it still have correlation with plaques lesion in arteries wall. The inhibitor (FAPI) agents of fibroblast activation protein have recently been used in the theranostic of a variety of epithelial tumors and fibrosis related inflammation in small-animal models. The aim of the study was to evaluate the application of 68Ga-FAPI positron emission tomography /computed tomography (PET/CT) scans atherosclerotic rabbits. Methods: The atherosclerotic plaques animal model was successfully established,atherosclerosis was induced through an atherogenic diet in New Zealand rabbit’s artery. Atherosclerosis progression was evaluated after atherogenic diet feeding (7, 14, 28, 56 days, respectively). The plaque formation was monitored with noninvasive ultrasound-inspection. Then we successfully synthesis the 68Ga-FAPI probes to detective atherosclerotic plaques in model animals. After injection of radionuclide labelled probes, a dynamic micro-PET/CT examining in same parameters respectively. After imaging, the mice were sacrificed by air embolism and the carotid arteries were taken out for making circular sections. The paraffin embedded specimens were sectioned with 5 μm thickness and stained with oil red. After staining, immunohistochemistry experiment was carried out to verify the effect of micro-PET/CT imaging.Results: The micro-PET/CT imagings successfully identified the atherosclerotic plaques in the aortal lesions of model rabbits. In addition, there is no evident accumulation of nuclide labelled drug in the blocking experiments. The results of vitro and immunohistochemistry experiment also provided pathological evidences for the evaluation of imaging effect. Conclusion: 68Ga labeled FAPI had the pretention to identify atherosclerotic plaques in arteries which may play an important diagnostic role in cardiovascular acute events._____________________________________________________________________________ Key words: Atherosclerosis; FAP; FAPI;PET/CT