By IANS,
Washington : Researchers may have overcome one of the biggest hurdles to developing new dementia drugs that breach the blood-brain barrier.
As part of a new study, they have blocked an immune response and cleared up 90 percent of the plaques in mice linked with Alzheimer’s disease, which helped them regain some of their lost memory.
The results surprised scientists, said Richard Flavell of Yale University and the study’s co-author.
Flavell’s team originally thought that blocking the immune system molecule TGF-β (or transforming growth factor), might actually increase the build-up of these amyloid plaques.
Earlier studies had shown that Alzheimer’s patients tend to have elevated amounts of TGF-β, which plays a key role in activating immune system response to injury.
Some had thought the presence of the molecule was simply an attempt to quiet the inflammatory response caused by the plaque build-up.
Instead, the team found that as much as 90 percent of the plaques were eliminated from the brains of mice genetically engineered to block TGF-β in the peripheral immune cells.
It was like a vacuum cleaner had removed the plaques,” Flavell said.
When the TGF-β pathway was interrupted in mice, programmed to have Alzheimer’s, they showed an improved ability to perform some tests, including navigating mazes when compared to mice without TGF-β blocked.
When TGF-β was blocked, the immune system seemed to unleash immune cells known as peripheral macrophages. The macrophages passed through the blood-brain barrier and surrounded the neurons and plaques in the brains of mice.
These findings have been published in the latest issue of the journal Nature Medicine.