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Amyloid-Targeting PET Tracer [18F]Flutemetamol Accumulates in Atherosclerotic Plaques.
Molecules. 2019 Mar 19;24(6). pii: E1072. doi: 10.3390/molecules24061072
Hellberg S, Silvola JMU, Liljenbäck H, Kiugel M, Eskola O, Hakovirta H, Hörkkö S, Morisson-Iveson V, Hirani E, Saukko P, Ylä-Herttuala S, Knuuti J, Saraste A, Roivainen A
Abstract:
Atherosclerosis is characterized by the accumulation of oxidized lipids in the artery wall, which triggers an inflammatory response. Oxidized low-density lipoprotein (ox-LDL) presents amyloid-like structural properties, and different amyloid species have recently been recognized in atherosclerotic plaques. Therefore, we studied the uptake of the amyloid imaging agent [18F]Flutemetamol in atherosclerotic plaques. The binding of [18F]Flutemetamol to human carotid artery plaque was studied in vitro. In vivo uptake of the tracer was studied in hypercholesterolemic IGF-II/LDLR-/-ApoB100/100 mice and C57BL/6N controls. Tracer biodistribution was studied in vivo with PET/CT, and ex vivo by gamma counter and digital ex vivo autoradiography. The presence of amyloid, ox-LDL, and macrophages in the plaques was examined by immunohistochemistry. [18F]Flutemetamol showed specific accumulation in human carotid plaque, especially in areas positive for amyloid beta. The aortas of IGF-II/LDLR-/-ApoB100/100 mice showed large thioflavin-S-positive atherosclerotic plaques containing ox-LDL and macrophages. Autoradiography revealed 1.7-fold higher uptake in the plaques than in a lesion-free vessel wall, but no difference in aortic tissue uptake between mouse strains were observed in the in vivo PET/CT. In conclusion, [18F]Flutemetamol binds to amyloid-positive areas in human atherosclerotic plaques. Further studies are warranted to clarify the uptake mechanisms, and the potential of the tracer for in vivo imaging of atherosclerosis in patients.
PMID: 30893771
Free Full-Text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471324/
Tags: atherosclerosis, beta-amyloid, humans, mice