Preliminary Biological Evaluation of F-18-FBEM-Cys-Annexin V a Novel Apoptosis Imaging Agent

摘要

A novel annexin V derivative (Cys-Annexin V) with a single cysteine residue at its C-terminal has been developed and successfully labeled site-specifically with F-18-FBEM. F-18-FBEM was synthesized by coupling F-18-fluorobenzoic acid (F-18-FBA) with N-(2-aminoethyl)maleimide using optimized reaction conditions. The yield of F-18-FBEM-Cys-Annexin V was 71.5% +/- 2.0% (n = 4, based on the starting F-18-FBEM, non-decay corrected). The radiochemical purity of F-18-FBEM-Cys-Annexin V was >95%. The specific radioactivities of F-18-FBEM and F-18-FBEM-Cys-Annexin V were >150 and 3.17 GBq/mu mol, respectively. Like the 1st generation F-18-SFB-Annexin V, the novel F-18-FBEM-Cys-Annexin V mainly shows renal and to a lesser extent, hepatobiliary excretion in normal mice. In rat hepatic apoptosis models a 3.88 +/- 0.05 (n = 4, 1 h) and 10.35 +/- 0.08 (n = 4, 2 h) increase in hepatic uptake of F-18-FBEM-Cys-Annexin V compared to normal rats was observed after injection via the tail vein. The liver uptake ratio (treated/control) at 2 h p.i. as measured via microPET correlated with the ratio of apoptotic nuclei in liver observed using TUNEL histochemistry, indicating that the novel F-18-FBEM-Cys-Annexin V is a potential apoptosis imaging agent.