Investigation of a Potential Scintigraphic Tracer for Imaging Apoptosis : Radioiodinated Annexin V-Kunitz Protease Inhibitor Fusion Protein

الملخص EN

Radiolabeled annexin V (ANV) has been widely used for imaging cell apoptosis.

Recently, a novel ANV-Kunitz-type protease inhibitor fusion protein, ANV-6L15, was found to be a promising probe for improved apoptosis detection based on its higher affinity to phosphatidylserine (PS) compared to native ANV.

The present paper investigates the feasibility of apoptosis detection using radioiodinated ANV-6L15.

Native ANV and ANV-6L15 were labeled with iodine-123 and iodine-125 using Iodogen method.

The binding between the radioiodinated proteins and erythrocyte ghosts or chemical-induced apoptotic cells was examined.

ANV-6L15 can be radioiodinated with high yield (40%−60%) and excellent radiochemical purity (>95%).

123I-ANV-6L15 exhibited a higher binding ratio to erythrocyte ghosts and apoptotic cells compared to 123I-ANV.

The biodistribution of 123I-ANV-6L15 in mice was also characterized.

123I-ANV-6L15 was rapidly cleared from the blood.

High uptake in the liver and the kidneys may limit the evaluation of apoptosis in abdominal regions.

Our data suggest that radiolabled ANV-6L15 may be a better scintigraphic tracer than native ANV for apoptosis detection.