'Holy grail' drug reverses devastating symptoms of Alzheimer's

Described as the "holy grail" of Alzheimer's research, the drug can improve memory in brains ravaged by the condition that affects millions around the world, including 500,000 Britons.

Although existing pills can delay the progress of symptoms including memory loss, none is capable of repairing the damage to the brain.

With 500 new cases of the disease diagnosed every day as people live longer, there is a desperate need for new treatments.

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Tests show that the new drug, being developed at St Andrews University, stops brain cells from dying in mice suffering from a condition similar Alzheimer's disease.

Crucially, the drug also improves the animals' memory and learning, suggesting that brain tissue destroyed by the disease is actually repaired.

Rebecca Wood of the Alzheimer's Research Trust, which funded the study, said: "A drug that can stop Alzheimer's disease from killing brain cells is the holy grail for researchers working to overcome the condition." Describing his results as "striking" researcher Dr Frank Gunn-Moore said: "Humans are always more complex than animals but if you can give somebody another six months of good quality life, that has huge implications."

The drug works by stopping a chemical reaction behind much of the brain cell death in the early stages of Alzheimer's.

Key players in the reaction are ABAD, an enzyme that in healthy people helps power the brain, and amyloid, a sticky protein that clogs up the brain in Alzheimer's patients.

When the two come together, they trigger the release of toxic chemicals which kill brain cells. This cell death leads to memory loss and, eventually, the loss of the ability to walk, talk and even swallow.

The St Andrews drug, currently known as Tat-mito-ABAD-DP, stops the reaction in its tracks, giving the brain time to heal.

When mice bred to suffer from a condition similar to Alzheimer's were injected with the drug, their memory improved and they found it easier to learn.

The scientists, who discussed their breakthrough in an article in the journal Molecular and Cellular Neuroscience, are now working on refining the drug to ensure it is suitable for human trials.

They are also searching for other similar compounds which may be even better at combating the disease.

However, while the work is groundbreaking, the extensive research and testing needed means that such a a drug is around a decade away from the market.

Should it prove successful in treating humans, it is likely it will be used in combination with other drugs, including vaccines which are being developed by other researchers.

"Our research holds a possible key for the treatment of Alzheimer's disease, particularly in its early stages," said Dr Gunn-Moore, a neurobiologist, who carried out the study in conjunction with American researchers.

"I am not saying it is a cure but it is a certainly a stepping stone. It has opened up a new avenue for us to look at.

"We will never have a one drug wonder, we will have to have combinations of drugs in the treatment of something like Alzheimer's disease."

The Alzheimer's Research Trust described the discovery as "very important" but cautioned that such a drug is still many years from the pharmacy shelf.

Chief executive Rebecca Wood said: "Alzheimer's is a complex and under-funded disease, so it is a real challenge to find the right targets to fight it.

"If researchers can find proof that inhibiting a particular reaction will prevent the death of brain cells then this is a real step forward - but we desperately need to fund many more steps if we are to beat this devastating disease and find a cure."

Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: "This study provides another important piece in the puzzle for understanding Alzheimer's disease and points toward a possible new treatment

target."

The most common form of dementia, Alzheimer's costs the NHS up to to £14billion a year - more than it spends in total on stroke, heart disease and cancer.

Experts predict that the ageing population will cause a global epidemic, with one in 85 people around the world having Alzheimer's by 2050.

A vaccine capable of stopping the disease in its tracks is being developed in Switzerland and could be available for use in as little as six years.