RT Journal Article
SR Electronic
T1 F-18 AV-45 (florpiramine F-18): A PET imaging agent for mapping beta-amyloid plaques in the brain
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1190
OP 1190
VO 50
IS supplement 2
A1 Seok Rye Choi
A1 Daniel Skovronsky
A1 Franz Hefti
A1 A Carpenter
A1 Geoffrey Golding
A1 Zhi-Ping Zhuang
A1 Nathaniel Lim
A1 Tyler Benedum
A1 Wei Zhang
A1 H Kung
YR 2009
UL http://jnm.snmjournals.org/content/50/supplement_2/1190.abstract
AB 1190 Objectives Beta-amyloid plaques in the brain is a major risk factor for Alzheimer’s disease. AV-45 (florpiramine F-18) is a plaques-specific imaging agent currently under a phase III clinical trial. We have fully characterized this tracer using in vitro binding and autoradiography techniques. Methods In vitro binding studies were performed using postmortem control and AD brain homogenates, Autoradiography of human brain sections and pathological staining in the same sections were also performed. Ex vivo autoradiography was performed in transgenic mice with beta-amyloid deposits in the brain. Results In vitro binding studies of AD brain homogenates showed a high binding affinity (Kd = 2-3nM). The Bmax values varied depending on AD samples (ranging from 3,000 to 8,000 fmol/mg protein). In vitro autoradioradiography of AD brain sections showed an excellent mapping of the density and regional localization of beta-amyloid plaques, while control brain exhibited no binding. The same highly localized plaque-staining were obtained using transgenic mice. The presence of plaques in human brain sections was confirmed by staining the same section with thioflavin S (a known plaque-specific dye). Screening of binding to other neuro-receptors or binding sites showed an uniformly low binding affinity, suggesting that the tracer only targets beta-amyloid plaques. Conclusions The results provide support indicating that F-18 AV-45 (florpiramine F-18) is a highly selective tracer for imaging beta-amyloid plaques in the brain. This new agent may be useful for imaging amyloid pathology for differential diagnosis of patients with dementia.