PhotoA lot of high-powered research is currently aimed at Alzheimer's disease, as the huge Baby Boom generation moves into old age.

Since age is a principal risk factor, health officials are concerned that the memory-robbing and ultimately fatal disease could become an epidemic. Scientists working independently have recently uncovered new information that may lead to improved treatments. Both involve genes.

At Indiana University (IU), a research team has identified an immune system gene associated with higher rates of amyloid plaque buildup in the brains of Alzheimer’s patients and older adults. This plaque is believed to be a primary cause of the disease.

Potentially more harmful gene

The variant occurs in the IL1RAP gene, and researchers say it is associated with even more plaque build-up than the previously discovered APOEe4 allele gene.

The new study found that the amyloid-associated IL1RAP variant was also associated with a faster loss of memory and overall cognitive ability.

"These findings suggest that targeting the IL1RAP immune pathway may be a viable approach for promoting the clearance of amyloid deposits and fighting an important cause of progression in Alzheimer's disease," said Andrew Saykin, director of the Indiana Alzheimer Disease Center and the national Alzheimer's Disease Neuroimaging Initiative Genetics Core.

In unrelated research, scientists at State University of New York (SUNY) have found that women who have the APOEe4 allele gene variant experience a steeper decline in body mass index (BMI) after age 70 than those women without the version of the gene, whether they go on to develop dementia or not.

Weight may be a clue

Why is this important? Because it adds to a body of evidence suggesting that body weight change may provide a tell, aiding doctors in the diagnosis and management of Alzheimer's disease.

Research team leader Deborah Gustafson says women tend to follow a U-shaped relationship between age and BMI, a common marker of overweight and obesity. From the time they enter middle age to the time they reach 70 years of age, the average adult tends to gain weight. In other words, that's the norm.

After age 70, weight tends to decrease on average. This weight change over the life course may be due to aging, changes in body composition, energy metabolism, sensory changes, and changes in the brain related to regulation of basic body processes.

But the researchers found that among adults who develop dementia, this pattern is altered. Studies have shown that being more overweight or obese in mid-life may increase risk for dementia. Studies have also shown that after age 70 years, adults who develop dementia may lose weight more rapidly compared to those who do not develop dementia.

Protective pounds

Being a little overweight in later life is protective against both dementia and death.

Gustafson says those with the APOEe4 allele gene experience greater or steeper decline in BMI after age 70 years, even if they don't develop dementia. The discovery, she says, may aid in understanding of how doctors can better intervene among those at highest risk for dementia.

Alzheimer's disease affects more than 5 million older Americans and there is currently no therapy proven to halt or reverse the underlying cause of the progressive symptoms of dementia, though recent research has seemed promising.

Researchers are increasingly focused on mechanisms involved with the deposit and clearance of amyloid plaques, particularly in early stages when symptoms are mild or not yet present.

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