Results 1 to 2 of 2

Thread: Researchers Still Hopeful for Alzheimer's Vaccine

  1. #1
    Senior Member Max's Avatar
    Join Date
    Jul 2001
    Location
    Montreal,Province of Quebec, CANADA
    Posts
    15,036

    Researchers Still Hopeful for Alzheimer's Vaccine

    Researchers Still Hopeful for Alzheimer's Vaccine
    Mon Oct 14,11:05 AM ET
    By Jacqueline Stenson

    NEW YORK (Reuters Health) - Progress toward an Alzheimer's disease (news - web sites) vaccine suffered a major setback earlier this year when a clinical trial was halted after some patients developed brain inflammation, but a follow-up report indicates that the vaccine was in fact targeting the brain-clogging plaques involved in the disease.



    And another new study found that a modified form of the vaccine worked in mice without causing the worrisome brain inflammation, raising hopes that a safe, effective vaccine for people could still be on the horizon.

    Both vaccines stimulate the immune system to produce antibodies against the beta-amyloid protein found in the plaques. But the modified vaccine relies on a smaller portion of the beta-amyloid protein than was used in the original vaccine. The modified vaccine was designed with the intent of avoiding the inflammation seen in 15 of 360 patients with mild to moderate Alzheimer's who received the original vaccine.

    In their research, Dr. JoAnne McLaurin, an assistant professor at the Center for Research in Neurodegenerative Diseases at the University of Toronto in Ontario, Canada, and colleagues found that mice given the modified vaccine developed antibodies that helped fight plaque, and no brain inflammation occurred.

    Besides leading to a potential vaccine for people, the researchers said the findings could potentially be used to develop a drug that would mimic the effects of the vaccine but would not require immunization. It is not clear why some of the patients in the human trial developed brain inflammation, but the investigators of that study are trying to determine the explanation and make modifications to render the vaccine safe.

    In the new analysis of two dozen patients who received the vaccine in Switzerland, the researchers found that the vaccine was working against beta-amyloid but was not attacking normal brain cells.

    Both studies were published in the October 15th online issue of Nature Medicine.

    "The findings show that the vaccine did precisely what it was intended to do in the first place--lead to the generation of antibodies that are specifically directed against the...brain amyloid plaques and the amyloid deposits in brain blood vessels," said Dr. Roger Nitsch, director of the division of psychiatry research at the University of Zurich.

    Nitsch and colleagues based their findings on blood samples of study participants. In the laboratory, they tested the effects of the antibodies on human brain tissue taken from deceased Alzheimer's patients and in mice bred to develop an Alzheimer's-like disease.

    Though the patients in the trial will not receive any additional doses of the vaccine, they will be followed to see if the antibodies remain in their bloodstream and if the vaccine helps prevent progression of Alzheimer's disease, Nitsch told Reuters Health.

    SOURCE: Nature Medicine 15 October 2002; doi:10.1038/nm783; nm790.

    ==============================
    "Events in our past seem to slip further away with time. But what happens when they circle back and meet us head on....in the present? Before we allow ourselves to be consumed by our regrets, we should remember the mistakes we make in life are not so important as the lessons we draw from them.." Outer Limits(Last supper)



  2. #2
    Senior Member Max's Avatar
    Join Date
    Jul 2001
    Location
    Montreal,Province of Quebec, CANADA
    Posts
    15,036

    Alzheimer Vaccine May Be Modified

    Alzheimer Vaccine May Be Modified
    Mon Oct 14,10:13 AM ET
    By RANDOLPH E. SCHMID, Associated Press Writer

    WASHINGTON (AP) - A new study suggests it may be possible to modify an experimental vaccine for Alzheimer's disease (news - web sites), making it safe for humans. The vaccine was withdrawn earlier this year because of side effects in test subjects.

    Related Quotes
    ELANZ
    DJIA
    NASDAQ
    ^SPC
    0.10
    7837.87
    1212.94
    837.69
    0.00
    -12.42
    +2.47
    +2.37



    delayed 20 mins - disclaimer
    Quote Data provided by Reuters



    A refined form of the vaccine for the degenerative brain disease was effective in mice, raising the possibility it might not produce the inflammation in humans that brought an end to the earlier clinical trials.

    But that remains only a possibility, requiring more research, said JoAnne McLaurin of the Centre for Research in Neurodegenerative Diseases at the University of Toronto, first author of the study being published Tuesday in the online edition of the journal Nature Medicine.

    In January, the Irish drug company Elan Corp. suspended a 360-patient experiment with the vaccine after 15 patients suffered serious brain inflammation. The company said in March it was abandoning the vaccine, although officials said it plans to continue seeking ways to slow the worsening of Alzheimer's.

    Dave Morgan, an Alzheimer's researcher at the University of South Florida, said other groups have also been working on the ways to refine the vaccine.

    The problem, Morgan said, is that it is not clear why the patients in the now-halted trial developed brain inflammation - whether immune cells entered the brain to attack the vaccine or if the vaccine provoked a reaction in the brain itself causing the inflammation.

    "Before we put any more vaccines in people we need to know what the problem was," said Morgan, who is not part of the Toronto research team.

    The goal of the vaccine is to clear away tangles of amyloid-beta protein, called plaques, that accumulate in the brains of Alzheimer's victims.

    In tests on mice, the vaccine produced antibodies directed against the AB proteins that cleared the plaques and reversed symptoms of brain degeneration.

    McLaurin, who is not connected to the Elan research, explained that her experiments in mice were aimed at finding out what the active antibody is and how it works.

    Her team of researchers found a way to produce antibodies against AB protein in mice using a vaccine that included only a small portion of AB rather than the entire molecule.

    This raises the possibility that a vaccine using only a portion of AB would be less likely to cause the inflammation that brought the earlier trial to a halt. It might also lead to development of a small molecule that mimics the vaccine, sidestepping the potential problems of the tested vaccine, McLaurin said.

    The response to the vaccine seems to target a specific group of AB in the body known as protofibrillar precursor, the study found.

    McLaurin's team included researchers at the University of Toronto and the University of Konstanz, Germany.

    In a separate paper in Nature Medicine, researchers headed by Roger M. Nitsch of the University of Zurich, Switzerland, reported that the human patients in the Elan trial did accumulate antibodies against AB.

    They said the antibodies recognized AB in tangles, diffuse AB deposits and AB in blood vessels of the brain and were able to cross the blood-brain barrier, which suggests they might be able to directly destroy plaques in the brain.

    However, the antibodies did not attack the longer form of AB that occurs in the nerve cells of healthy people as well as Alzheimer's patients.

    The function of that type of AB is unknown, but healthy nerve cells can contain a lot of it. This selectivity is good news, since an attack on the longer form of AB could result in complications.

    ==============================
    "Events in our past seem to slip further away with time. But what happens when they circle back and meet us head on....in the present? Before we allow ourselves to be consumed by our regrets, we should remember the mistakes we make in life are not so important as the lessons we draw from them.." Outer Limits(Last supper)



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •