A new PET imaging nuclear medicine radiotracer could help researchers to better understand the brain of aging individuals, according to a recent study published in an issue of The Journal of Nuclear Medicine.
Previous studies have shown that α4β2 nicotinic acetylcholine receptor (α4β2-nAChR) is of lowered density in the brain of aging patients and those suffering from neurodegenerative disease, particularly in the hippocampus and in the cortex.
According to the researchers, this receptor is responsible for learning to some extent, and even a partial loss of activity in α4β2-nAChR can have extensive effects on neurotransmission across neural networks. They have also found that high-performing and fast α4β2-nAChR-targeting nuclear tracers are confined to imaging outside the thalamus while the receptor is densely expressed inside the thalamus of the brain.
A research team analyzed the pharmacokinetic behavior of the new PET imagining radiotracer for the α4β2-nAChR which is known as 18F-XTRA. The team experimented the tracer on 17 individuals with prime focus on the outer thalamus region of the brain. The researcher explained the entry and distribution of 18F-XTRA inside the brain to be very quick.
Martin Pomper, MD, Ph.D. said that using the new PET nuclear tracer, a data was presented to determine α4β2-nAChR distribution in the brain. He added, the potential use of 18F-XTRA in research and clinical trials can be supported by faster uptake of the brain, quick pharmacokinetics, and its ability to bind into extra-thalamic region of the brain within 90-minute scan. It has also been found that lower binding of the radiotracer in the hippocampus is a sign of healthy aging. From methodological and biological perspectives, it is one of the critical findings, said Dr. Pomper.
The team further said that these findings can be effectively used in future studies to monitor and analyze any changes in the human brain, particularly related to aging and degeneration of neurons. The new PET imagining radiotracer may be sensitive to measure any loss of activity in α4β2-nAChR in aging brain. According to Dr. Pomper, it is a promising tool for future study of changes in cholinergic signals of the brain over healthy aging which may be related to memory changes during the lifespan.