New Mechanism Uncovered In Dementia

Credit: Reigh LeBlanc

Researchers across the world are still wrapping their heads around dementia, but a team has now uncovered an added mechanism that may play an important role. 

In the modern world we've become accustomed to being 'cured' of many conditions, and going to the doctor to be told there's little we can do is incredibly frustrating. The plethora of chronic and age-related diseases out there are incredibly complicated, but we are making slow and steady progress. We might not have hit the nail on the head yet in regards to Alzheimer's, but we'll get there eventually and every feather in our bow is a step closer to a 'cure'. 

A work in progress

Many camps are still debating what causes neuro-degenerative diseases like Alzheimer's, but while they are a team has discovered an additional mechanism which could prove a novel target. This new aspect still involves amyloid plaques, but focuses on their disruption of blood flow in the brain. 

The scientists found that a certain type of cell in the brain called an astrocyte (which actually outnumber neurons) is prevented from doing its job correctly by these amyloid plaques. Astrocytes are involved in a huge range of functions, including waste disposal, nutrient delivery and maintenance of correct blood flow around the brain. In a healthy brain these are able to remove amyloid fragments, but when a plaque builds it prevents this process from happening. 

"We found that amyloid deposits separated astrocytes from the blood vessel wall. 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."

Amyloid plaque (dark) staining in the cerebral cortex

Stiff blood vessels

These amyloid clumps were also found to coat and harden blood vessels, reducing their flexibility. This could severely impact on blood flow in the brain and potentially limit crucial oxygen supply. 

"Vascular amyloid may be the culprit in Alzheimer's disease symptoms, especially considering that the amyloid exoskeleton might limit the supply of oxygen and glucose to the brain regions that need them most. This could also explain the cognitive decline in people with Alzheimer's disease, as the disease is associated with reduced cerebral blood flow."

But is it safe to remove them? 

The problem with targeting amyloid is that previous efforts have had mixed results and scientists are unsure whether removing the plaque at later stages could do more damage than good. However, whatever the outcome, more work on this mechanism could reveal new therapeutic targets in the near future. 

Read more at MedicalXpress