Synthesis and biological evaluation of 68Ga-NOTA-CD44: a novel tracer targeting atherosclerotic plaques / 中华核医学与分子影像杂志

ABSTRACT

Objective:To construct 68Ga-1, 4, 7-trizacyclononane-1, 4, 7-triacetic acid (NOTA)-CD44 as a novel atherosclerosis tracer targeting hyaluronic acid (HA), and evaluate its biological property and molecular imaging features. Methods:Low molecular weight (LMW) recombinant human CD44 protein was selected, and the C-terminal of the protein was modified by sulfonation and coupled to the bifunctional ligand NOTA to synthesize a novel molecular probe 68Ga-NOTA-CD44 targeting HA. The biological properties of the probe, such as labeling rate and in vitro stability, were studied. Three atherosclerotic plaque model mice and three normal C57BL/6 mice were studied by 68Ga-NOTA-CD44 microPET/CT imaging and pathological examination. Results:68Ga-NOTA-CD44 tracer was synthesized and purified with the radiochemical purity above 99%, and the specific activity was up to 62.22 MBq/nmol. lts stability was good in PBS, and the radiochemical purity was over 90% after incubation for 3 h. After intravenous injection, the probe was metabolized mainly by the kidneys, and its metabolic level decreased successively in the liver, lungs and blood. MicroPET/CT imaging results of atherosclerotic model mice suggested that the uptake in the plaque of abdominal aorta was higher at 60 min after injection, with SUV max and target/background ratio (TBR) max of 1.14±0.02 and 4.95±0.93, and the probe had certain atherosclerotic plaque eroded targeting, which was consistent with the pathological result. Conclusions:As a novel probe, 68Ga-NOTA-CD44 is simple to prepare and has a high labeling rate. It has good physicochemical properties and in vivo biological properties, and can display atherosclerotic eroded plaques sensitively. 68Ga-NOTA-CD44 has a promising prospect to be a new molecular probe for early noninvasive recognition of atherosclerotic eroded plaques.