Scientists at UCLA (University of California - Los Angeles) have developed and used a new and innovative brain scanning technology, Positron emission tomography (PET) along with patient-specific information on Alzheimer's disease risk for tracking brain aging. Published in the January issue of Archives of General Psychiatry, this study provides "a window into the brain" of living people , revealing hallmarks of neurodegeneration, ie. plaques and tangles.
"Combining key patient information with a brain scan may give us better predictive power in targeting those who may benefit from early interventions, as well as help test how well treatments are working," said study author Dr. Gary Small, who holds UCLA's Parlow-Solomon Chair on Aging and is a professor at the Semel Institute for Neuroscience and Human Behavior at UCLA.
A new chemical marker, FDDNP injected intravenously ,which binds to plaque and tangle deposits in the brain, has been used and was tested on 76 non-demented volunteers. The PET brain scans revealed the areas of accumulation of abnormal protein deposits being mainly in the medial and lateral temporal regions of the brain and areas involved with memory, having a direct correlation with old age.
The research revealed that APOE-4 gene allele heightens the risk for developing Alzheimer's disease as thirty-four of the 76 volunteers who carried the gene showed higher FDDNP levels in the frontal region of the brain, also involved in memory as compared to those without it.
"We found that for many volunteers, the imaging scans reflected subtle brain changes, which take place before symptoms manifest," said Small, who is also director of the UCLA Center on Aging.
"This type of scan offers an opportunity to see what is really going on in the brain," he said.
The other group of 36 volunteers had mild cognitive impairment (MCI), a condition that increases the risk of developing Alzheimer's disease. The concentration of FDDNP
in such patients was found to be higher in the medial temporal brain regions than normal volunteers.
"We could see more advancing disease in those with mild cognitive impairment, who are already demonstrating some minimal symptoms," Small said. "Eventually, this imaging method, together with patient information like age, cognitive status and genetics, may help us better manage brain aging."
In future, according to Small, a brain scan and a genetic test would be able to predict the risk and can be controlled in a similar way as cholesterol or high blood pressure. This would help delay future neurodegeneration, thus protecting the brain from extensive damage through medications and other interventions and the effectiveness of the treatments can also be monitored.
PET, with the FDDNP probe, is the only imaging technology that provides a full profile of neurodegeneration giving measures of both plaques and tangles - the physical evidence of Alzheimer's disease in the brain.
"The fact that we can see tangles as well as amyloid plaques is critically important in early detection of brain aging, since the tangles are the first abnormal proteins that appear in the brain, long before dementia is clinically obvious to the physician," said Dr. Jorge R. Barrio, a study author and professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA.
Currently, the new FDDNP-PET scans are used in a research setting, but clinical trials are in development to bring the technology to wider patient use.
The research was funded by both government and nonprofit agencies, including the National Institutes of Health, the U.S. Department of Energy, the Ahmanson Foundation, the Larry L. Hillblom Foundation and the Tamkin Foundation.
