Alzheimer's disease is the most common of the 100 types of dementia that afflict more than 700,000 people in the UK.

As the population ages and longevity rates increase the problem grows. By 2025 there will be more than one million people with dementia in the UK and 1.7 million by 2051. Better treatments are desperately needed.

Dementia, which causes memory loss, confusion and problems coping with every day activities, brings misery to sufferers and close relatives.

Two thirds of people with late onset dementia live at home, meaning that families bear the burden of care. The best that patients can be offered are drugs that slow the rate of decline, and in about 30 per cent of cases reverse some symptoms for a time.

Dr Susanne Sorensen, head of research at the Alzheimer’s Society, says: “Alzheimer’s disease causes the gradual death of brain cells, until most of the brain is dead. In terms of stem-cell research, one possibility is to put the gene that makes growth hormone into stem cells. These could then be put into the brain in the hope that the growth hormones would stimulate the brain’s own stem cells into growing and replacing the dead cells.

“Our main hope is that stem cells will be a major laboratory tool. One prospect is to use chimera cells – cells from a cow that have had the DNA taken out and replaced with DNA from a patient who has the disease.

“Using chimera cells would make it quicker to test drugs and would reduce the number of animals used in tests. Stem cells can be taken from adult organs or embryonic tissue. The embryonic cells are superior because they have the ability to grow into any sort of cell whereas stem cells from adults have already turned into particular types of cells.”

Dr Virginie Sottile, at Queen’s Medical Centre, Nottingham University, is working on understanding how to persuade adult bone marrow stem cells to change into brain cells.

She says: “Bone marrow is a good source of stem cells and if you use the patient’s own cells there are no rejection issues when they are put back.

“We are experimenting to understand how cells are regulated to see if the switch could take place. The research is at a very preliminary stage trying to understand the mechanisms that make stem cells do what they do.

“We know from postmortem examination of people who have suffered brain damage that the stem cells located near the nose have started the process of regrowing brain cells to replace the dead cells, so this is something that the brain does naturally.”

David Jones, a retired teacher, has seen his mother Lillian, 90, decline over seven years from an active pensioner who enjoyed playing bowls, watching television, walking, cooking and reading thrillers to someone who is confused and anxious.

He said: “It’s a real tragedy. She’s not the same person and gets little enjoyment from life. Effective treatment for Alzheimer’s is urgently needed. It took a long time to get doctors to prescribe one of the treatments that is available at present, but I saw no improvement. They say it will have slowed her decline. But how can I tell?

“Mother has changed from an amusing, unselfish person into someone who can’t be reassured, can’t enter into another’s feelings and wanders around the house at all hours. Alzheimer’s doesn’t just destroy the life of the victim it also ruins the lives of carers.”

www.alzheimers.org.uk