A new vaccine may prevent the development and progression of Alzheimer's disease.

As the most common form of senile dementia, Alzheimer's disease affects more than 18 million people worldwide. With the graying of American baby boomers, this number is expected to climb rapidly over the next few decades.

Alzheimer's disease, which typically strikes individuals over the age of 65, affects mood, memory and behavior. Although the disease may take years to progress, people with Alzheimer's ultimately deteriorate to the point that they are unable to care for themselves.

While the exact cause of Alzheimer's is unknown, a leading theory attributes it to development of plaques or tangles in the brain. These structures, which interrupt the flow of messages between brain cells, are created by the accumulation of protein fragments called beta amyloid.

"Beta amyloid is a sticky substance that deposits itself in the brain, and interferes with brain functions like thinking and memory," said Dr. Howard Weiner, co-director of the Center for Neurologic Diseases at Brigham and Women's Hospital in Boston. "The goal of Alzheimer's research is to find a way to remove beta amyloid buildup from the brain."

Earlier attempts to produce an Alzheimer's vaccine were halted in 2002, when the experimental vaccine triggered encephalitis, a life- threatening swelling of the brain, in 15 of the 360 elderly volunteers involved in the study.

According to Weiner, "Human trials with the previous vaccine used injections of the beta amyloid protein itself. The new vaccine takes a totally different approach."

For the past three decades, Weiner's research has focused primarily on the role of immune therapy in multiple sclerosis (MS). According to Weiner, who serves as the director of Partners Multiple Sclerosis Center in Boston and is the author of the book "Curing MS,""We didn't start out by looking specifically for an Alzheimer's vaccine: We asked one question, and we got a totally different answer."

When Weiner and his colleague, Dan Frenkel, gave laboratory mice an MS-like disease, they were surprised to discover that the animals began clearing beta amyloid deposits from their brains.

"The mice's brains were actually manufacturing cells that ate up the beta amyloid," said Weiner. "We then asked ourselves if there was a way that we could make this happen without giving the mice the MS-like disease."

After a large series of experiments, the research team succeeded, using a vaccine made of a pair of chemical compounds known to be safe for use in humans. The compounds, which are found in vaccines against infectious agents such as shigella, and in medications used to treat multiple sclerosis, work by boosting the immune system.

Weiner and his colleagues speculated that the compounds would trigger the body's immune system to rid the brain of the beta amyloid plaques thought to be responsible for causing Alzheimer's disease. Their goal was to stimulate special cells, called microglia, to clear away the deposits.

To test their theory, the researchers used mice that had been genetically engineered to develop beta amyloid deposits in their brains, in amounts similar to those that would be present in human Alzheimer's patients. The vaccine was given nasally to the mice for a period of six weeks.

When the brain tissue of vaccinated mice was examined, Weiner and his colleagues found a 73 percent reduction in the amount of beta amyloid present.

In addition, there was no evidence of the encephalitis that had occurred with the earlier vaccine.

The next step is to begin clinical trials to determine if the vaccine will have the same results in humans. Weiner cautioned, "Sometimes, things that work in animals don't work the same way in people, but we're very hopeful that this vaccine will slow the progression of Alzheimer's disease in humans."

Weiner said that he and his research team plan to begin testing the new Alzheimer's nasal vaccine in humans in 2006, pending approval by the U.S. Food and Drug Administration.

"If all goes well with the clinical trials, and if we have positive results," he said, "we could see an Alzheimer's vaccine on the market in four or five years, at the earliest."

Weiner speculated that the drug initially would be administered to people diagnosed Alzheimer's disease, as well as to individuals with mild cognitive impairment, a condition that increases the risk of developing Alzheimer's.

"It's possible that in the future, the vaccine might be available to the general population to prevent Alzheimer's disease," Weiner said, "but right now, we've got to take one step at a time." mentalhelp.net

Could a simple word test be used to identify people who might be suffering from the very early stages of Alzheimer's disease? British scientists think so.

Results of a study presented at a science conference on Tuesday revealed that people in the first stages of the incurable illness cannot write down as many animals and fruits in one-minute period as healthy individuals.

Professor Andy Ellis of the University of York in England also discovered that the characteristics of the words the Alzheimer's sufferers produced were different.

They retained very familiar words, ones heard frequently and words learned in early, rather than late, childhood.

"Just by looking at the characteristics of the words people produced you could correctly determine whether somebody came from the group of healthy controls or the Alzheimer's patients," he told the British Association science meeting.

Ellis and his colleagues believe the results of the study, involving 96 patients and 40 healthy controls with an average age of 77, could form the basis of a test to determine whether elderly patients are just having a "senior moment" or the memory lapse is more serious.

"It is possible that exploring the characteristics of the words that are still available to them might be one of the ways one can begin to detect that something is going wrong," said Ellis.

"There is considerable value in identifying people who are beginning to show the first signs and this might be one way of doing that."

DEMENTIA

Alzheimer's is the leading cause of dementia in the elderly and affects an estimated 12 million people around the globe. The incidence of the disease is expected to increase as the population ages.

There is no cure for the progressive illness, which robs people of their memory and mental ability, but drug treatments may slow the early progression of the disorder. Animals listed in the written test by the healthy elderly people included giraffes, zebras and badgers -- creatures seldom seen on the Alzheimer's patient list.
"They are animals whose names children tend to learn more at around the age of 6-10 rather than 1-5," he said, adding they are creatures less talked or heard about than cats or dogs.

Ellis said a test based on the findings may help to assist with the early diagnoses of the illness and allow people to receive treatment as soon as possible.

"The next phase of the research is to look into the possibility of making a prognostic guide," Ellis added.
Reuters.com

The link between age-related macular degeneration (AMD) and smoking is now as robust as that between smoking and lung cancer, they say.

Yet many smokers are still unaware that their habit could cost them their sight.

AMD Alliance UK and the Royal National Institute of the Blind are calling for specific warnings on cigarette packets.
Smoking is the only proven cause of AMD that people can do anything about
Steve Winyard of RNIB and AMD Alliance UK

They would also like the government to fund an awareness campaign to alert people to the dangers of smoking, as well as the introduction of a complete ban on smoking in all enclosed public places across the UK.

AMD usually develops after a person reaches 50 years and affects the central part of the retina of the eye.

It is the UK's leading cause of sight loss - there are around 500,000 people in the UK with AMD.

An estimated 54,000 people have the condition as a result of smoking.

Ignorance

Yet a report by AMD Alliance UK reveals that only 7% of people know that AMD affects the eyes, based on a survey of 1,023 UK adults.

However, seven out of 10 smokers would either stop smoking permanently (41%) or cut down (28%) if they thought it could harm their eyesight.


A patient's view
Pauline Edwards, 50, from Salford, has AMD after smoking most of her adult life. Pauline said: "I smoked for years. Now I have AMD, am partially sighted in one eye and am likely to go blind. When you smoke you cannot imagine what it is like to have lung cancer and especially when you are young the risk of dying earlier doesn't come into it. I am a nurse, I saw people die from smoking-related diseases and that did not make me kick the habit. But if I had been told that I could lose my sight because of smoking I would have given up. I stopped the day I found out."


Studies have shown that people who stopped smoking 20 years ago have a similar risk of developing AMD as non-smokers do and the risk starts to decrease after 10 years of not smoking.

Steve Winyard, RNIB's head of campaigns and chairman of AMD Alliance UK, said: "Smoking is the only proven cause of AMD that people can do anything about, yet people are not aware of the link and most people have not even heard of the condition.

"The message is simple: do not take up smoking and if you do - stop.

"People also need to make sure they have regular eye tests to check their eyes are healthy - an eye test can save your sight."

Nick Astbury, president of the Royal College of Ophthalmologists, said: "This is a chilling statistic but it's not too late to give up."

A spokeswoman from the Department of Health said "We know that for people to change their behaviour we need to communicate the facts about smoking, as well as provide support to help them quit."

She said there were campaigns raising the awareness of the health dangers of smoking and passive smoking.

However, she said the public were less supportive of measures to make all bars and pubs smoke free.

She said they were clamping down on tobacco advertising, but that warnings on cigarette packets were determined by, and therefore a matter for, the European Commission.

The British Medical Association said it supported the call for AMD warnings on cigarette packs.

There are two types of AMD, wet and dry. Some 90% of cases are dry AMD, which cannot be treated.

The remaining 10% are wet AMD, which can be treated.