About this Journal Submit a Manuscript Table of Contents
Journal of Biomedicine and Biotechnology
Volume 2011 (2011), Article ID 675701, 8 pages
http://dx.doi.org/10.1155/2011/675701
Research Article

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

1Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan
2Division of Isotope Application, Institute of Nuclear Energy Research, Taoyuan 325, Taiwan
3Department of Veterinary Medicine, National Taiwan University, Taipei 106, Taiwan
4Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei 112, Taiwan
5EVAS Therapeutics LLC, 613 Huntley Heights Drive, Ballwin, MO 63021, USA
6Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, 259 Wen-Hwa First Road, Kwei-Shan, Taoyuan 333, Taiwan
7Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan 333, Taiwan

Received 29 November 2010; Accepted 15 February 2011

Academic Editor: David J. Yang

Copyright © 2011 Mei-Hsiu Liao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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.