Cell growth—not death—linked to Alzheimer’s

A profusion of blood vessels within the brain may explain the destructive nature of Alzheimer’s disease, according to scientists at the University of British Columbia.

Researchers said that while the death of cells has been a major focus of Alzheimer’s research, their findings show that the disease might instead be caused by the propagation of cells in blood vessel walls.

Examining brain tissue from mouse models of Alzheimer’s, researchers found nearly double the density of capillaries compared to normal mice. They also found a similarly higher density of capillaries in the brain samples of people who had died of the disease compared to people who had died of other causes.

The research, published online in PLoS One, theorizes that the profusion of blood vessels is stimulated by amyloid beta, a protein fragment that has become a hallmark of Alzheimer’s.

“When the blood vessels grow, the cells of the vessel walls propagate by dividing,” researchers said. “In the process of splitting into two new cells, they become temporarily rounded in shape, and that undermines the integrity of the blood-brain barrier, potentially allowing harmful elements from outside the brain to seep in.”

The deterioration of the barrier might in turn allow the depositing of amyloid beta, which accumulates around neurons and eventually kills them.

Researchers said that given their findings, the next step in treating Alzheimer’s should include treatments that target blood vessel growth.

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