Monday, November 07, 2011

Green tea and Alzheimer's

Lasers can be used to force drugs into cells to destroy the plaques that cause memory loss in Alzheimer's disease

Also from New Scientist:

It may sound like a strange brew, but green tea and red light could provide a novel treatment for Alzheimer's disease. Together, the two can destroy the rogue “plaques” that crowd the brains of people with the disease. The light makes it easier for the green-tea extract to get to work on the plaques. Andrei Sommer at the University of Ulm in Germany, and colleagues, have previously used red light with a wavelength of 670 nanometres to transport cancer drugs into cells. The laser light pushes water out of the cells and when the laser is switched off, the cells “suck in” water and any other molecules, including drugs, from their surroundings.

Now, Sommer's team have found that the same technique can be used to destroy the beta-amyloid plaques in Alzheimer's. These plaques consist of abnormally folded peptides, and are thought to disrupt communication between nerve cells, leading to loss of memory and other symptoms. The team bathed brain cells containing beta-amyloid in epigallocatechin gallate (EGCG) – the green-tea extract known to have beta-amyloid inhibiting properties – at the same time as stimulating the cells with red light for 1 minute. Beta-amyloid in the cells reduced by around 60 per cent. Shining the laser light alone onto cells reduced beta-amyloid by around 20 per cent.

It can be difficult getting drugs into the brain, but animal experiments show that the green-tea extract can penetrate the so-called blood-brain barrier when given orally together with pulses of red light. The light, which can penetrate tissue and bone, stimulates cell mitochondria to kick-start a process that increases the barrier's permeability, says Sommer. This could form the basis of a therapy for Alzheimer's, with or without complementary drugs

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