Preliminary biological evaluation of ¹⁸F-FBEM-Cys-Annexin V a novel apoptosis imaging agent

Molecules. 2015 Mar 17;20(3):4902-14. doi: 10.3390/molecules20034902.

Abstract

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 18F-FBEM. 18F-FBEM was synthesized by coupling 18F-fluorobenzoic acid (18F-FBA) with N-(2-aminoethyl)maleimide using optimized reaction conditions. The yield of 18F-FBEM-Cys-Annexin V was 71.5% ± 2.0% (n = 4, based on the starting 18F-FBEM, non-decay corrected). The radiochemical purity of 18F-FBEM-Cys-Annexin V was >95%. The specific radioactivities of 18F-FBEM and 18F-FBEM-Cys-Annexin V were >150 and 3.17 GBq/µmol, respectively. Like the 1st generation 18F-SFB-Annexin V, the novel 18F-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 18F-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 18F-FBEM-Cys-Annexin V is a potential apoptosis imaging agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Annexin A5 / chemistry*
  • Annexin A5 / metabolism*
  • Apoptosis
  • Cysteine / chemistry
  • Hepatobiliary Elimination
  • Humans
  • Liver / pathology*
  • Male
  • Maleimides / chemistry
  • Mice
  • Models, Animal
  • Positron-Emission Tomography / methods*
  • Radiopharmaceuticals / chemistry
  • Radiopharmaceuticals / metabolism*
  • Rats

Substances

  • Annexin A5
  • Maleimides
  • N-(2-(4-18F-fluorobenzamido)ethyl)maleimide
  • Radiopharmaceuticals
  • Cysteine