Link between diabetes and Alzheimer's disease bolstered

Date:
September 28, 2021
Source:
University of Nevada, Las Vegas
Summary:
Researchers show that chronic hyperglycemia impairs working
memory performance and alters fundamental aspects of working
memory networks.



FULL STORY ==========================================================================
A team of UNLV neuroscientists has strengthened the link between Type
II diabetes and Alzheimer's disease.


==========================================================================
In a study published in the September issue of the journal Communications Biology, researchers show that chronic hyperglycemia impairs working
memory performance and alters fundamental aspects of working memory
networks.

"Diabetes is a major risk factor for developing Alzheimer's disease,
but it is not clear why," says James Hyman, study author and associate professor of psychology at UNLV. "We show that a central feature of
diabetes, hyperglycemia, impairs neural activity in ways that are similar
to what is observed in preclinical Alzheimer's disease models. This is
the first evidence showing neural activity changes due to hyperglycemia
overlap with what is observed in Alzheimer's systems." The research
project is the continuation of a six-year collaboration between Hyman
and coauthor Jefferson Kinney, chair and professor in UNLV's Department
of Brain Health, to better understand why diabetes can elevate risk for Alzheimer's. The work is funded by a grant from the National Institute
on Aging.

"As the number of Alzheimer's disease diagnoses rapidly rises and the
incidence of diabetes and pre-diabetes has accelerated, it's crucial
that we understand what connects these two disorders," Kinney said.

The researchers found that two parts of the brain that are central to
forming and retrieving memories -- the hippocampus and the anterior
cingulate cortex - - were over-connected, or hypersynchronized. When
it came time to remember the correct information and complete a task,
these two parts of the brain -- which are affected early in Alzheimer's progression -- were over-communicating with each other, sparking errors.

"We know synchrony is important for different parts of the brain to
work together. But, we're finding more and more these days, that the
key with neural synchrony is it has to happen at the right time, and it
has to happen with control," Hyman said. "Sometimes, there's just too
much 'talking' between certain areas and we think this leads to memory difficulties, among other things." Hyman compares the situation to a
CEO who hands over a majority of the company's business operations to
their son, who then decides to upend previous communication structures
and become the sole gatekeeper of information.

"The only communication the CEO has is with one person, as opposed to
talking with all of the other people in the office," Hyman said. "It is possible that in Alzheimer's patients there's over-connection in certain
areas where there should be flexibility. And in the models in our study,
we're seeing evidence of that in real-time at these crucial moments to do
the task." This most recent finding not only provides novel information
about brain activity in the hyperglycemia model, it also provides an
additional important measure that can be used for continuing research.

"Our next step is to combine the biochemical markers and electrophysiology
data to test specific mechanisms responsible and potential treatments,"
said Kinney.

"This research will now be able to work towards understanding
the risk as well as what may be able to be done to help." ========================================================================== Story Source: Materials provided
by University_of_Nevada,_Las_Vegas. Original written by Natalie
Bruzda. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ryan. A. Wirt, Lauren. A. Crew, Andrew. A. Ortiz, Adam. M. McNeela,
Emmanuel Flores, Jefferson. W. Kinney, James M. Hyman. Altered
theta rhythm and hippocampal-cortical interactions underlie
working memory deficits in a hyperglycemia risk factor model of
Alzheimer's disease.

Communications Biology, 2021; 4 (1) DOI: 10.1038/s42003-021-02558-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210928121324.htm

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