A $2 million grant to UC Davis researchers will fund one of the first studies investigating how diabetes may contribute to memory loss and possibly Alzheimer's disease in older people, aided by advanced imaging techniques that show the functioning brain.

Charles DeCarli, professor of neurology and director of the UC Davis Alzheimer's Disease Center, and his colleagues recently were awarded the grant from the Larry L. Hillblom Foundation to study the impact of diabetes on aging and memory loss. The grant will fund a four-year study that will focus on the brains of diabetics, looking at how the disease changes the brain and whether information is processed any differently in a diabetic's brain compared to those without the disease.

"We know that diabetes increases the risk for late-life dementia, but no one knows how," said DeCarli. "We are going to be the first to comprehensively analyze the workings of the memory systems in the brains of diabetics. "We think that either something about diabetes is damaging the hippocampus, the memory organ of the brain, or that the disease is causing small strokes that damage the brain over time."

Medical advancements have improved life expectancy and contribute to Americans who are 65-and-older being the fastest-growing segment of the population. Many in this age group, particularly those older than 75, experience memory loss. Additionally, age is the single-greatest risk factor for Alzheimer's disease, with a doubling of the risk every five years after 65. An increasing number of senior citizens also suffer from chronic illnesses, such as hypertension, heart disease and diabetes.

Scientists do not know how diabetes, which impairs the body's ability to control the amount of sugar in the blood, might be contributing to Alzheimer's disease, a progressive neurological disorder caused by changes in brain tissue with age. Both diabetes and Alzheimer's are associated with memory loss that can lead to dementia. Studying how memory works in diabetics is a crucial first step in unraveling the puzzling interaction between these two diseases.

The grant will fund the creation of the Larry L. Hillblom Network for Cognitive Neuroscience of Diabetes, Aging and Memory. It will include four researchers from complementary fields of brain research. In addition to DeCarli, other faculty include Andrew Yonelinas, a professor of psychology and associate director of the UC Davis Center for Mind and Brain; John Olichney, a professor of neurology at the Center for Mind and Brain; and Charan Ranganath, associate professor of psychology and a member of the UC Davis Center for Neuroscience.

DeCarli and his colleagues will recruit 200 individuals with diabetes who do not have dementia and 50 age-matched healthy individuals. Using state-of-the-art structural and functioning brain imaging, the team will be looking for changes in the shape of the brain and changes in brain tissue as they relate to vascular function.

The team will do this using the latest brain imaging techniques. For example, to determine which parts of the diabetic's brain are involved in memory, researchers will take images of a patient's brain using functional magnetic resonance imaging (fMRI) while the participant is performing a memory task. These images will tell them which parts of the brain are active during these tasks.

"Using these and other methods, we believe we can get some idea of the memory systems damaged by diabetes," DeCarli said.

The hope, DeCarli said, is that scientists who are armed with an understanding of how diabetes changes the brain can then develop ways of mitigating the damage.

"Our goal is to reduce the impact of diabetes so that people can lead more active and independent lives," he said.

UC Davis Health System is an integrated, academic health system encompassing UC Davis School of Medicine, the 577-bed acute-care hospital and clinical services of UC Davis Medical Center, and the 800-member physician group known as UC Davis Medical Group.

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