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Nicotine drug ‘may slow dementia
Nicotine-based drugs may help delay the moment a person with dementia has to enter a care home, say researchers.
Nicotine has toxic effects, and carries a strong risk of addiction, but scientists have shown it can also boost learning, memory and attention.
The effect is small, but it may help give dementia patients up to six extra months of independent living.
A team at King’s College London have demonstrated the positive effects of nicotine in experiments on rats.
They showed that nicotine boosted the animals’ ability to carry out a task accurately – particularly when they were also distracted.
When able to give full concentration, the animals responded correctly to stimuli about 80% of the time. Nicotine boosted the accuracy rate by about 5%.
However, when distracted, the animals’ success rate fell to about 55%. In this case nicotine brought it back up to around the 85% level.
Biochemical mechanisms
The King’s team, based at the Institute of Psychiatry, studied the mechanisms which underpin the effects produced by nicotine.
They showed how proteins on the surface of cells respond to the compound, and pinned down the role of several key chemicals in the brain, including dopamine and noradrenaline.
It transpired that there are only subtle biochemical differences in the way nicotine stimulates the brain, and triggers addiction.
Several nicotinic drugs are already in development, but the King’s team hopes its work will speed up the discovery of agents which give the brain a bigger boost than nicotine, with longer lasting effects.
Lead researcher Professor Ian Stolerman said: “Nicotine, like many other drugs, has multiple effects, some of which are harmful, whereas others may be beneficial.
“It may be possible for medicinal chemists to devise compounds that provide some of the beneficial effects of nicotine while cutting out the toxic effects.”
Professor Stolerman stressed that the positive effects produced by nicotine were small, and would be of no benefit to most people.
However, he said they could potentially make a difference to dementia patients.
He added that the “cognitive boost” that many smokers experience from nicotine may contribute to the pleasure they get from their habit.
‘Don’t smoke’
Professor Clive Ballard, of the Alzheimer’s Society, said: “Although nicotine has therapeutic qualities, when it is absorbed through smoking the health risks outweigh the benefits.
“Smoking increases risk of vascular dementia, the second most common form of dementia and is associated with a number of other health risks.
“More research is now needed to find a safe and effective treatment for dementia, with the potential benefits of nicotine, but without the health risks.”
Rebecca Wood, of the Alzheimer’s Research Trust, agreed that people should not be tempted to smoke to try to ward off dementia. She said the best way to minimise risk was to eat a balanced diet and exercise regularly.
Professor Stolerman said there was no reason to believe that nicotine or smoking reduced the risk of getting dementia – it only helps to reverse symptoms.
It is estimated that 700,000 people in the UK live with dementia.
The research will be presented to a Federation of European Neuroscience Societies conference in Geneva.
source: BBC News
Blood pressure ‘link to dementia’
Controlling blood pressure from middle-age onwards may dramatically reduce the chances of developing dementia, researchers have said.
Two studies support a link between high blood pressure and dementia risk – with one by an Imperial College London team suggesting treatment could cut this.
This study, by published in the Lancet Neurology journal, found blood pressure drugs reduce dementia by 13%.
The Alzheimer’s Society said better control could save 15,000 lives a year.
As many as one in four people has high blood pressure, in many cases undiagnosed or untreated.
The precise reasons why high blood pressure might increase the risk of dementia are not fully understood although many scientists believe that it can starve the brain of bloodflow and the oxygen it carries.
Patients suffering this restricted bloodflow are often described as having “vascular dementia”, and account for approximately a quarter of dementia patients.
Other types of dementia, such as Alzheimer’s disease, have no obvious link to bloodflow, but some experts think that blood pressure may still be somehow contributory in some cases.
The Lancet Neurology study looked at a trial of elderly patients with high blood pressure to see if those who were receiving treatment were less likely to develop any form of dementia compared with those left untreated.
Clear benefit
The trial was stopped early after the benefits of treatment in terms of reducing strokes and heart disease were so obvious it became unethical to deny them to everyone.
Although this meant that no benefits in terms of dementia could be found, when these results were combined with other similar studies in different age groups, the incidence of dementia was 13% lower in the treated groups.
Dr Ingmar Skoog, from the Institute of Neurosciences at Sweden’s Goteburg University, said that the need to treat high blood pressure, reducing heart attacks and strokes, was clear, even without the additional results on dementia.
Rebecca Wood, from the Alzheimer’s Research Trust, said the finding was an “exciting development”, which, if repeated, could offer hope to the 700,000 people in the UK with dementia.
Healthy living
The Alzheimer’s Society, however, stressed the need to try to prevent the disease.
Its own unpublished research suggested that vascular dementia was six times more likely to develop in people who had high blood pressure in their 40s and 50s.
If “best practice” in blood pressure treatment was applied to the UK population, it said, with every case detected and treated appropriately, this would save 15,000 lives a year.
Professor Clive Ballard, its director of research, said: “Only half of people over 65 receive effective treatment, yet we know treatment works.”
The charity’s chief executive, Neil Hunt, urged everyone, even those in middle age, to have regular blood pressure and cholesterol checks
source: BBC News
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