Immune cells 'vacuum up' Alzheimer's clumps
[The beauty of this crazy idea is that it can be tested by already approved drugs.]
newscientist.com
18:00 30 May 2008 NewScientist.com by Alison Motluk
Debris-gobbling immune cells can be enticed into the brain to eat away the amyloid plaques associated with Alzheimer's disease, according to a study in mice.
The study suggests a promising new approach in the fight against Alzheimer's – and several drug candidates are already on pharmaceutical company shelves, waiting to be tried out.
Richard Flavell at Yale University in New Haven, Connecticut, and his colleagues created a double transgenic mouse, dubbed Tg2576-CD11c-DNR. One gene predisposed it to develop amyloid plaques in its brain that mimic Alzheimer's disease, while another blocked the activity of TGF-beta, a cytokine.
The researchers had expected the double-transgenic mice to do even more poorly than their single-transgenic Alzheimer's cagemates. But as the animals got to old age – about 18 months – the Tg2576-CD11c-DNR mice performed significantly better at traversing through various mazes. When the researchers examined their brains, they found up to 90% less amyloid.
For reasons that are not entirely clear, selectively blocking TGF-beta allowed macrophages, immune cells that ingest unwanted materials, to get across the blood brain barrier and into the brain. There, they feasted on amyloid plaques. "It was like a vacuum cleaner," says Flavell.
Several drug candidates already exist that are known to block TGF-beta in a similar way. It's too early to know if such a drug would be able to roll back the symptoms. "But even to reverse the decline would be an improvement," says Flavell.
Journal reference: Nature Medicine, DOI: 10.1038/nm1781 |
