Scientists Discover Brain Changes in Young Adults at Genetic Risk for Alzheimer's Disease.

Business Editors & Medical Writers

STOCKHOLM, Sweden--(BUSINESS WIRE)--July 23, 2002

Decades before symptoms appear, scientists can detect abnormalities in the brains of healthy adults in their 20s and 30s who are at genetic risk for developing Alzheimer's disease, says Eric

Reiman and colleagues presented their findings today at the 8th International Conference on Alzheimer's Disease and Related Disorders.

Using a brain-imaging technique called positron emission tomography (PET), scientists were able to study young adults carrying apolipoprotein E-(epsilon)4 (ApoE-(epsilon)4), one of three common forms of a gene that codes production of a cholesterol-carrying protein. Individuals with ApoE-(epsilon)4, which occurs in about one-fourth of the population, have an increased risk -- although not a certainty -- of developing late-onset Alzheimer's disease. Late-onset Alzheimer's disease is the most common form of Alzheimer's, in which memory and thinking problems begin after the age of 60.

A dozen healthy young adults who carry the ApoE 4 gene were compared to 15 young adults who do not carry this susceptibility gene. Clinical ratings and neuropsychological tests to assess the participants' memory and thinking, and PET imaging and powerful brain mapping software were used to map differences in brain activity between the ApoE4 carriers and noncarriers.

Although the young adults carrying the ApoE4 gene performed normally on the memory and thinking tests, Reiman and colleagues found that they had abnormally low brain activity in the same regions of the brain as patients with the clinical diagnosis of Alzheimer's disease.

"Young adults at risk of Alzheimer's disease have detectable brain abnormalities several decades before the possible onset of memory and thinking problems," said Reiman, who also serves as professor of psychiatry at the University of Arizona and director of the Arizona Alzheimer's Research Center. "Our findings underscore the possibility of finding treatments to prevent Alzheimer's disease at the earliest possible time and in the most effective way, and they reinforce the possibility of using PET to help establish the effectiveness of these prevention therapies without having to wait many years to determine whether or when treated individuals develop symptoms. Meanwhile, it is important to recognize that PET is not clinically indicated to predict a person's risk for developing this terrible disorder."

Based on previous research, it is believed that the low brain activity found in patients clinically affected by Alzheimer's disease, and in cognitively normal people at genetic risk for the disorder, progress as the person ages. Studies led by Reiman and previously published in the New England Journal of Medicine and the Proceedings of the National Academy of Sciences found that 50- to 65-year-old carriers of the ApoE4 gene had abnormally low brain activity in the same brain regions as clinically affected patients, that this activity continues to decline over time, and that PET could efficiently test the potential of treatments to prevent Alzheimer's disease.

"I think it is very important to emphasize that APOE-(epsilon)4 is only one of many risks for Alzheimer's disease. Researchers have estimated there are a number of additional genes (not yet identified) that will both increase and decrease risk," explains Marilyn Albert, Ph.D., Professor of Psychiatry and Neurology, Harvard Medical School. "It is also clear there are environmental risk factors that influence the development of Alzheimer's disease. It is important to understand the impact of these risks on the brain so that we can understand how best to reduce risk foD, and develop better treatments, and this study is part of that effort."

The Alzheimer's Association is hosting the 8th International Conference on Alzheimer's Disease and Related Disorders, July 20-25, 2002, in Stockholm, Sweden. The conference is the largest gathering of Alzheimer researchers in history. As many as 4,000 researchers from around the world will present and discuss the findings of nearly 2,000 studies on the prevention, diagnosis and treatment of Alzheimer's disease.

The Alzheimer's Association is the premier source of information and support for the millions of Americans with Alzheimer's. The largest private funder of Alzheimer research in the United States, the Association has committed $138 million toward research into the disease.

    Abstract No. 1545

    Title:
    Abnormalities in regional brain activity in young adults at
    genetic risk for late-onset Alzheimer's disease

    Session: Tuesday, July 23, 3-5 p.m.

    Researchers:
    Eric Reiman, Kewei Chen, Gene Alexander, Richard Caselli, Dan
    Bandy, Anita Prouty, Christine Burns

Editor's Note: News releases of selected research presented at the 8th International Conference on Alzheimer's Disease and Related Disorders are available on the Alzheimer's Association's Web site, at www.alz.org/internationalconference/newsroom.htm. Scientific abstracts are accessible on the Web at http://www.alz.org/internationalconference/programs.htm, then click on Program Navigator link.