A new study using PET imaging and MRI scans showed three different changes in the brains of people with Down syndrome, who are at higher risk for developing Alzheimer's disease.

The findings could help in the development of treatments to delay or prevent Alzheimer's symptoms, according to a study recently published in the journal Alzheimer’s & Dementia.

Down syndrome is caused when an individual has an extra copy of chromosome 21, which carries a gene for the amyloid precursor protein, leading to the over-production of amyloid, a protein linked to Alzheimer’s disease. Because people with Down syndrome are living longer, almost 80 percent will develop Alzheimer’s.
Scientists at the Banner Sun Health Research Institute in Arizona used PET imaging to detect the accumulation of beta-amyloid and to look at the brain activity of five people with Down syndrome who had already demonstrated symptoms of Alzheimer’s, 12 people with Down syndrome who had no symptoms of Alzheimer’s, and nine people who did not have either Down syndrome or Alzheimer’s. They also did MRI scans to measure gray matter volume in the study participants' brains.

Researchers found that the study participant group with Down syndrome who also had Alzheimer’s symptoms had a much higher accumulation of beta-amyloid, lower brain activity in the parts of the brain known to be affected by Alzheimer’s, and smaller gray matter volumes than those in the other two groups. They also found that the participants with Down syndrome who had no symptoms of Alzheimer’s had more accumulation of amyloid protein than the healthy control group. This led researchers to conclude that Alzheimer’s-associated brain changes in the Down population generally occurs between the ages 35 to 40, before the onset of Alzheimer’s symptoms. This could help pinpoint when to initiate investigational treatments, they said.

The number of people with Down syndrome who go on to develop Alzheimer’s symptoms has tripled in the last 20 years, says Dr. Marwan Sabbagh, a neurologist and director of the Banner Sun Health Research Institute, who served as the study’s lead researcher. Further research will help find ways to treat and prevent Alzheimer’s in these individuals, which could lead to effective Alzheimer’s prevention therapies for the general population.

“We believe that amyloid positivity precedes symptoms,” Sabbagh told DOTmed News. “We think this is also true in the non-Down’s population.”

Led by the Banner Alzheimer's Institute, the Alzheimer’s Prevention Initiative is conducting additional research into people at genetic risk for developing Alzheimer’s, including trials to investigate whether anti-amyloid drugs can prevent or delay the emergence of Alzheimer's symptoms.

These latest results come on the heels of an announcement Thursday that the American College of Radiology and the Alzheimer's Association are collaborating on a four-year research study to determine the value of beta-amyloid imaging in diagnosing and treating Alzheimer’s disease and other forms of dementia. The study will assess the impact of amyloid PET imaging on the short-term management of patients, as well as on hospitalizations and emergency room visits.

More Industry Headlines