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European Journal of Nuclear Medicine

, Volume 26, Issue 11, pp 1392–1399 | Cite as

99mTc-MAMA-chrysamine G, a probe for beta-amyloid protein of Alzheimer’s disease

  • Nancy A. Dezutter
  • René J. Dom
  • Tjibbe J. de Groot
  • Guy M. Bormans
  • Alfons M. Verbruggen
Original article

Abstract.

Chrysamine G (CG), an analogue of Congo red, is known to bind in vitro to the β-amyloid protein (Aβ 10-43) and to homogenates of several regions of the brain of Alzheimer’s disease (AD) patients. We synthesised a conjugate of 2-(acetamido)-CG with a bis-S-trityl protected monoamide-monoaminedithiol (MAMA-Tr2) tetraligand, which was efficiently deprotected and labelled with a 75% yield with technetium-99m, to obtain 99mTc-MAMA-CG. In mice, 99mTc-MAMA-CG was cleared mainly by the hepatobiliary system, resulting in a fast blood clearance. Brain uptake of 99mTc-MAMA-CG was low. Co-injection with the blood pool tracer iodine-125 human serum albumin (125I-HSA) demonstrated a brain/blood activity ratio for 99mTc-MAMA-CG that was significantly higher than that for 125I-HSA (t test for dependent samples, P<0.02), indicating the ability of 99mTc-MAMA-CG to cross the blood-brain barrier. In vitro autoradiography demonstrated pronounced binding of 99mTc-MAMA-CG to β-amyloid deposits in autopsy sections of the parietal and occipital cortex of an AD patient as compared with controls. Adding 10 µM Congo red during incubation displaced the binding of 99mTc-MAMA-CG. Congo red staining and autoradiography identified the same lesions. 99mTc-MAMA-CG seems to bind selectively to β-amyloid deposition in human brain parenchyma and blood vessels in vitro and thus might be a lead compound for further development of a useful tracer agent for the in vivo diagnosis of Alzheimer’s disease.

Key words: Alzheimer’s disease Diagnosis Congo red Chrysamine G Technetium-99m 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Nancy A. Dezutter
    • 1
  • René J. Dom
    • 2
  • Tjibbe J. de Groot
    • 1
  • Guy M. Bormans
    • 1
  • Alfons M. Verbruggen
    • 1
  1. 1.Laboratory of Radiopharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, K.U. Leuven, Leuven, BelgiumBE
  2. 2.Department of Neuropathology, University Hospital Gasthuisberg, Leuven, BelgiumBE

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