Recent advances in the development of amyloid imaging agents.

Abstract

Excessive amyloid-beta (Abeta) deposition in the brain is one of the most crucial events in the early pathological stage of Alzheimer's disease (AD). Therefore, Abeta deposits have enough potential to become a useful biomarker for not only an early diagnosis of AD, but also for the assessment of the clinical efficacy of anti-Abeta therapies, if they can be measured non-invasively and reliably in living patients. As a potent candidate technique to measure this biomarker, PET amyloid imaging using a radioligand for Abeta deposits has received much attention. A large number of Abeta ligands have been synthesized and evaluated as candidates for amyloid imaging agents. These can be classified into six categories of derivatives: Congo-red, Thioflavine T, stilbene, vinylbenzoxazole, DDNP, and miscellaneous. Many of these derivatives exhibit high binding affinities to Abeta fibrils (below 20 nM) and some of them also show excellent brain pharmacokinetic profiles. The concept of amyloid imaging is currently being tested in human PET studies using optimized amyloid imaging agents. Despite the small number of subjects, these studies have demonstrated sufficiently promising results. This review article provides an overview of recent advances in the development of amyloid imaging agents, and includes: a summary of the fundamental basis and clinical significance of amyloid imaging; lists of binding affinity data for 135 compounds classified into 12 molecular frameworks; a comprehensive discussion of the in vitro and in vivo features of representative Abeta ligands; and a discussion of the current state of clinical evaluation of these amyloid imaging agents (PIB, SB-13, BF-227, and FDDNP).

• Authors: Shozo Furumoto, Nobuyuki Okamura, Ren Iwata, Kazuhiko Yanai, Hiroyuki Arai, Yukitsuka Kudo
• Journal: Current topics in medicinal chemistry (Curr Top Med Chem) Vol. 7 Issue 18 Pg. 1773-89 ( 2007) ISSN: 1873-4294 [Electronic] United Arab Emirates
• PMID: 17979786 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid beta-Peptides
• Biomarkers
• Coloring Agents
• Contrast Media
• Ligands
• Radioisotopes

Topics

• Alzheimer Disease (diagnosis)
• Amyloid beta-Peptides (analysis)
• Biomarkers (analysis)
• Coloring Agents
• Contrast Media (pharmacokinetics)
• Humans
• Ligands
• Positron-Emission Tomography (methods)
• Radioisotopes