PET probes for imaging brain acetylcholinesterase

Area of Science:

• Neuroimaging
• Biochemistry
• Pharmacology

Background:

• Acetylcholinesterase (AChE) imaging is vital for dementia diagnosis, understanding disease progression, and evaluating antidementia drugs.
• Cholinesterase inhibitors are key treatments for dementia, necessitating methods to monitor their efficacy and dosage.
• The distribution of AChE in the living brain can be visualized using radioprobes.

Purpose of the Study:

• To review the development of positron emission tomography (PET) probes for imaging AChE in the brain.
• To describe the principles of measuring AChE activity using substrate-type PET radioprobes.
• To discuss in vitro reagents derived from substrate-type PET probes for specific AChE activity measurement.

Main Methods:

• Utilized substrate-type PET probes, such as N-[(11)C]methylpiperidin-4-yl acetate ([(11)C]MP4A) and its propionate [(11)C]MP4P.
• Reviewed the development of radiolabeled cholinesterase inhibitors as PET probes for AChE mapping.
• Discussed in vitro assays for AChE activity measurement using substrate-type PET probes.

Main Results:

• [(11)C]MP4A and [(11)C]MP4P have been instrumental in demonstrating reduced AChE activity in dementia patients.
• These probes have shown the bioavailability of AChE inhibitors, guiding the development of (18)F-labeled derivatives.
• Various radiolabeled cholinesterase inhibitors have been developed as PET probes for brain AChE mapping.

Conclusions:

• PET imaging with substrate-type radioprobes provides a valuable tool for assessing AChE activity in the brain.
• This imaging modality supports dementia diagnosis, drug development, and personalized treatment strategies.
• Further development of PET probes enhances the ability to measure AChE activity both in vivo and in vitro.