Research & Development/Project

Development of diagnostic probe for Alzheimer’s disease

     

The Imaging Department develops the diagnostic probe for Alzheimer’s disease.
The strategy is to develop a probe (compound) that binds to bad proteins, such as Amyloid β and Tau that specifically appear in the brain that is affected by Alzheimer’s disease, and diagnose the disease by measuring the accumulation of probes inside the brain (accumulation of bad proteins).

Let‘s assume an 80 year old gets Alzheimer’s. Amyloid β is thought to have started accumulating in the brain 30 years ago and Tau is thought to have started accumulating more than 10 years ago (Figure 1).
Figure 1, out of these two bad proteins, the probes that bind to Aβ allow diagnosis of both presymtomatic and very early stage of Alzheimer’s disease. The probes that bind to Tau is thought to be able to diagnose the severity of Alzheimer’s disease.
The Imaging Research Department has implemented 12 years of probe development and research and screening of about 4,000 compounds to development of PET (Positron-Emission Tomographic device) probes that has already begun imaging Amyloid β and human search clinical studies (Figure 2).
Figure 2 was [11C] labeled PET probe, but the imaging department also developed [18F] labeled probe that is easy to use at the clinical sites and has a longer half-life, and is currently implementing human search clinical studies.
This ongoing study is developing PET probe that binds to the bad protein Tau and light imaging probe that binds to Amyloid β and/or Tau proteins. It is predicted that the former diagnoses the severity of Alzheimer disease and the latter takes advantage of its easy and safe features to mass-screen Alzheimer’s disease.
Figure 3 is an image of the brain when the light imaging probe is administered to a genetically modified mouse that has accumulated Amyloid β in its brain.
In time, there will be 30 million Japanese and about 200 million people from developed countries over the age of 65. We continue to research with the belief that there will come a day when most of these populations will be able to receive presymptomatic or early diagnosis for Alzheimer’s disease and that our research and this diagnosis will contribute to eliminating the Alzheimer’s disease.

 

Figure 1: Expression of bad proteins and onset of clinical symptoms of Alzheimer’s disease
Yasuo Ihara, Hiroyuki In“Arai: In“ Do not get Alzheimer’s disease ”, Cited from Asahi Shimbun, Tokyo 2007 (Partly modified)

Figure 2: Alzheimer’s disease diagnosis using PET probe [11C] BF-227 that binds to bad protein Aβ
Left: Aged normal subject
Right: Patient with Alzheimer’s disease

Figure 3 Image of the brain when the light imaging probe is administered to a transgenic mouse with accumulatedAβ in its brain
Left: Administration of light imaging probe to a wild-type mouse
Right: Administration of light imaging probe to a transgenic mouse