Scientists have uncovered a mechanism in the brain that could account for some of the neural degeneration and memory loss in people with Alzheimer’s disease.

The researchers discovered that a common symptom of Alzheimer’s disease – the accumulation of amyloid plaques along blood vessels – could be disrupting blood flow in the brain. The results were published in the journal Brain.

The team discovered that the blood flow regulation of astrocytes — the most populous cell type in the brain — is disrupted by plaques formed of misfolded amyloid protein around blood vessels. In a healthy brain, amyloid protein fragments are routinely broken down and eliminated.

The presence of amyloid proteins around blood vessels in the brain is a hallmark of Alzheimer’s disease, yet it wasn’t understood if the proteins did any harm. Now, the research team has found that they do.

“We found that amyloid deposits separated astrocytes from the blood vessel wall,” said Stefanie Robel, a research assistant professor at the Virginia Tech Carilion Research Institute and a coauthor of the paper. “We also found that these amyloid deposits form an exoskeleton around the blood vessels, a kind of cast that reduces the pliability of the vessels.”

The exoskeleton is known as a vascular amyloid. Its inelasticity might result in lower blood flow, which could account for Alzheimer’s symptoms, such as memory lapses, impaired decision-making, and personality changes.

 

Source: Virginia Tech News

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