뇌를 막히게 하는 단백질들을 제거해주는 항체(antibody)의 단회투여는 쥐의 기억력을 향상시켰고 인간에게 이용될 수 있는 알츠하이머병(Alzheimer's disease)에 대한 백신 개발을 이끌어줄 수 있을 것이라고 연구진들이 일요일(현지시각)에 밝혔다.
Single Vaccine Improves Alzheimer's in Mice -Study
WASHINGTON (Reuters) - A single dose of an antibody that cleans up brain-clogging proteins improves memory in mice and might lead to an Alzheimer's disease vaccine for people, researchers reported Sunday.
The experiment also sheds new light on the causes of Alzheimer's, a fatal and incurable disease that affects four million Americans and millions more around the world.
A team at Lilly Research Laboratories in Indianapolis, owned by Eli Lilly, Washington University in St. Louis and Universite Louis Pasteur in Strasbourg, France, has been reporting steady progress in mice with an antibody called m266.
In the mice, which are genetically engineered to develop a syndrome similar to Alzheimer's in humans, the antibody homes in on the beta amyloid peptide, which forms the characteristic brain-clogging "plaques" seen in the disease.
The antibody attaches to the peptide and causes it to be flushed out from the brain into the blood. Previous studies have shown that mice do better on a memory test after getting injected with the antibody.
Steven Paul of Lilly, who helped lead the research, said he and colleagues had assumed that the antibody was pulling beta amyloid out of the gummy plaques in the brain.
"What surprised us was that this was not the case," Paul said in a telephone interview.
Reporting in the journal Nature Neuroscience, Paul said it seemed the antibody was in fact pulling beta amyloid out of the system before it was being deposited in the brain -- and that this had immediate effects on the mice.
"First we took very, very old mice. They were two years old and they had lots of plaque in the brain," Paul said.
The team gave injections of the antibody to mice for six weeks. "What we found was that with one particular task, an object-recognition memory test, the animals looked pretty much like wild-type mice -- the animals that had no Alzheimer's disease," he added.
BRAINS STILL "CHOCK-FULL OF PLAQUE"
"We thought 'wow'. We looked at their brains and found no reduction at all in the plaque. The treated and untreated animals alike were chock full of plaque."
So they gave a new group of mice just a single injection of the antibody and tested them. These mice also did noticeably better on the memory tests, Paul said.
The study team had believed the antibodies were clearing plaque from the brains of the mice and thus improving brain function. It appears instead the antibodies were affecting the peptide before it could form plaque.
This suggests that beta amyloid circulates and causes problems in the brain even before it gets dumped into a blob -- even though it is clear that the clogs themselves kill brain cells and affect memory and other brain processes.
Paul warned that this information is a long way from being useful to any human Alzheimer's patient.
Attempts to come up with an Alzheimer's vaccine can be risky. Last month, Irish drug company Elan dropped development of its experimental vaccine against beta amyloid after 15 patients who got it developed a mysterious brain inflammation.
Nonetheless, a variety of approaches are possible, Paul said. "Can we block the form of this peptide, can we increase its clearance from the brain, can we neutralize it?" he asked.
Several recent studies have shown that people destined to develop Alzheimer's start developing the telltale clumps of beta amyloid and tangles of brain cells 10 to 20 years before they ever get any symptoms.
Eventually patients start to become forgetful, progressing within a few years to being unable to find their way around and, eventually, to care for themselves.
출처 : Reuters
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