Researchers in Leeds have uncovered a new clue in the search for fresh treatments for Alzheimer's disease.
The team at the University of Leeds have discovered higher levels of a certain enzyme in the brains and blood of people with the disease.
Research has shown the enzyme, alkaline phosphatase, to be associated with a greater loss of cognitive function.
Scientists believe the discovery could be used to help clinical trials for new treatments.
The researchers, led by Nigel Hooper, professor of Biochemistry at the University of Leeds, studied blood plasma samples and post-mortem brain tissue, provided by the MRC London Neurodegenerative Diseases Brain Bank, from people with Alzheimer's and from healthy people.
They found that people with the disease had more of the enzyme in one of the first regions of the brain to be damaged in Alzheimer's than healthy people when they died.
Professor Hooper said: "We were surprised to find that levels of this enzyme in people's blood correlated with cognitive decline, and we think this could be significant for helping to monitor people with Alzheimer's over a period of time.
"We hope that with more research, our results could be useful to people who are testing new drugs, giving us a better chance of finding an effective treatment to fight Alzheimer's."
He added: "Dementia is not a normal part of ageing, and with research it can be beaten, but we need to know much more about its causes in order to develop effective treatments.
"I hope our research can help bring us a step closer to that goal."
The work in Leeds is part-funded by Alzheimer's Research UK and the Medical Research Council (MRC).