X-Message-Number: 28118
From: "Basie" <>
Subject: digitoxin can protect your brain after clinical death
Date: Sun, 25 Jun 2006 15:17:36 -0400

Heart drugs may shield brain
Last updated: Wednesday, June 21, 2006
New laboratory research suggests that digoxin and digitoxin, two widely used 
heart drugs, could protect the brain from damage during a stroke.
The findings are preliminary, and scientists have only tested the drugs on 
the brain cells of rats. However, confirming the drugs' effects in human 
trials could lead to a powerful new weapon against stroke, the researchers 
said.

No protection for neurons

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Despite billions of dollars spent on research, "not a single stroke drug has 
come out that protects neurons from the damage caused by stroke. There's 
this amazingly huge need for a protective drug," noted senior researcher 
Donald Lo, director of the Centre for Drug Discovery at Duke University 
Medical Centre in Durham, North Carolina.

In search of a new stroke treatment, Lo and colleagues tested thousands of 
existing drugs by injecting them into dishes containing slices of rat 
brains. Because scientists can simulate the effects of stroke in brain 
cells, they can save money by not having to test the drugs on live rats.

Nearly all the drugs tested failed to prevent neurons from dying. But a 
chemical found in digoxin and digitoxin worked, according to the study, 
which is published in this week's issue of the Proceedings of the National 
Academy of Sciences.

Chemical gives six-hour protection
The chemical, known as neriifolin, protected the cells of the brain slices 
from damage for six hours or more, the researchers reported. The chemical - 
one of a class of molecules called cardiac glycosides - also appeared to 
prevent brain damage in live rats.

Currently, no drug has been shown to directly protect sensitive neurons 
during a stroke, said Lo, who is also an associate professor of neurobiology 
at Duke. One commonly well-known stroke drug, tissue plasminogen activator, 
or tPA, is a "clot buster" that breaks open blockages in blood vessels. But 
tPA only works if given within a few hours after a stroke.

Digoxin is a common heart drug used to treat heart failure and atrial 
fibrillation, a kind of irregular heartbeat. Digitoxin is also used to treat 
heart problems, but it's used less now than in the past, Lo said.

"The most exciting outcome would be if digoxin itself could be used in 
treatment of stroke," Lo said. "But there are a lot more studies that need 
to be done before that is tested in humans."

Another expert agreed that a pinch of caution is warranted.

Mice are not men
"Lots of agents have been found useful as neuroprotectants in mice and rats 
and did not pan out to work in people for various reasons," said Dr Rafael 
H. Llinas, medical director of neurology at Johns Hopkins Bayview Medical 
Centre in Baltimore.

Still, it's possible that a treatment might be able to protect the brain 
from the effects of a stroke, or "at least prolong the period when the brain 
is able to tolerate not getting enough oxygen, blood and energy," he said.

Llinas noted, for example, that some people survive being trapped under the 
ice in a frozen lake for a significant period of time. "Then, when they are 
removed and resuscitated, they are neurologically intact."

Currently, he said, researchers are trying to develop a treatment that both 
protects the brain, perhaps by slowing its function, but doesn't put the 
heart in danger.- 

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