New research led by Nottingham University in the UK suggests abnormal levels of seven proteins in spinal fluid could be markers for the early stages of Alzheimer’s disease, raising hopes of a test for a disease that is difficult to diagnose at the beginning. The researchers write about their findings in the Journal of Alzheimer’s Disease.

Study co-author Dr Kevin Morgan, professor of Human Genomics and Molecular Genetics at Nottingham, told the press on Tuesday that the findings are “a new lead for improving early diagnosis of Alzheimer’s disease”.

An early diagnosis of Alzheimer’s disease would help people prepare for the future and also enable them to be involved in clinical trials at a much earlier stage of the disease, when treatments are more likely to show positive results, he added.

About 820,000 people in the UK have dementia, of which Alzheimer’s disease is the most common form. Dementia often develops slowly and is not always obvious in the early stages. It can be difficult to distinguish from the mild forgetfulness often seen in normal ageing.

Morgan and colleagues compared samples of cerebrospinal fluid (CSF) from 33 people with Alzheimer’s disease, 10 people with mild cognitive impairment, and 20 healthy older people. Mild cognitive impairment is a condition where people have problems with thinking and memory but not to an extent that it interferes with everyday life.

They compiled profiles of the proteins in each sample and then compared them with each other to see if they could find something distinctive in the samples from people with Alzheimer’s disease.

The results showed that the samples from people with Alzheimer’s diseases tended to have higher levels of four proteins, and lower levels of three other proteins.

A protein called SPARCL1 proved to be the strongest predictor for Alzheimer’s. When the researchers tested the samples using only this protein, they could tell whether a person had Alzheimer’s disease to an accuracy of 65%.

This accuracy went up to 95% when they tested for abnormal levels of all seven proteins.

The researchers repeated the tests with a new set of CSF samples from 32 healthy people and 30 people with Alzheimer’s disease. This time, when they tested for all seven proteins, the accuracy was 85%.

The team now plans to use their findings to develop a blood test for an early diagnosis of Alzheimer’s disease.

Morgan said:

“It will also be important to investigate what causes these specific proteins to change as Alzheimer’s develops.”

By understanding the underlying changes in the biochemistry of Alzheimer’s, we have a better chance of developing new treatments, he said, adding that:

“Dementia can only be defeated through research, and I hope these findings could take us a step closer to that goal.”

Dr Marie Janson, Director of Development at Alzheimer’s Research UK, who part-funded the study, said the findings have “opened up a new avenue for research”.

She emphasized how difficult it is to diagnose Alzheimer’s, as memory problems can be symptomatic of various conditions.

“This study has the potential to help create a vital tool for doctors to identify patients that need further investigation – but these results must now be followed up in order to achieve that goal,” she added.

Funds from the Big Lottery Fund and the EU FP6 Program through BIOPATTERN also supported the work.

Written by Catharine Paddock PhD