Preclinical evaluation of an F-labeled Tenascin-C aptamer for PET imaging of atherosclerotic plaque in mouse models of atherosclerosis.

Tenascin-C is an extracellular matrix glycoprotein strongly expressed in coronary atherosclerotic plaque. Aptamers are single-stranded oligonucleotides that bind to specific target molecules with high affinity. This study hypothesized that tenascin-C expression at atherosclerotic plaque in vivo could be detected by tenascin-C specific aptamers using positron emission tomography (PET). This paper reports the radiosynthesis of a fluorine-18 (F)-labeled tenascin-C aptamer for the biodistribution and PET imaging of the tenascin-C expression in apolipoprotein E-deficient (ApoE) mice. The aortas ApoE mice showed significantly increased positive areas of Oil red O staining than control C57BL/6 mice, and tenascin-C expression was detected in foam cells accumulated in the subendothelial lesions of ApoE mice. The ex vivo biodistribution of the F-labeled tenascin-C aptamer showed significantly increased uptake at the aorta of ApoE mice, and ex vivo autoradiography of aorta revealed the high accumulation of the F-labeled tenascin-C aptamer in the atherosclerotic lesions of ApoE mice, which was consistent with the location of the atherosclerotic plaques detected by Oil red O staining. PET imaging of the F-labeled tenascin-C aptamer revealed a significantly higher mean standardized uptake in the aorta of the ApoE mice than the control C57BL/6 mice. These data highlight the potential use of tenascin-C aptamer to diagnose atherosclerotic lesions in vivo.