A "striking" discovery by University of Otago researchers could pave the way for Alzheimer's disease to be diagnosed by a simple blood test.
The researchers have found a promising new marker among a small number of molecules, within a larger class of molecules called microRNA.
The marker molecules, found both in the human brain and blood, were "exceptionally good" at detecting Alzheimer's disease, the researchers said.
A member of the Otago team, biochemist Professor Warren Tate, said Health Research Council programme funding had been crucial in gaining the "promising" results.
And researchers were seeking further funding which would be "critical" in continuing the work.
Further key research is needed to confirm and clarify aspects of the earlier testing, and, if the results can be confirmed, it is understood that a blood test could become available about five years after that.
Professor Tate, an RNA biologist in the Otago team, said Otago researchers were also at a "promising and exciting stage" in their hunt for new ways to treat Alzheimer's.
These other results would not be available until later this year, and "important groundwork" still had to be done before a clinical trial for a therapy was possible, he said.
Blood plasma microRNA had previously been shown to reflect various disease processes, and specific microRNA were linked to neurological diseases.
This led Dr Joanna Williams, a senior lecturer in anatomy at Otago University, to suggest that blood microRNA levels may reflect changes in the brain.
Dr Williams led the screening of microRNA in study participants' blood samples, supported by a member of her team, Diane Guevremont.
The specific set of blood microRNA markers identified by the Otago researchers can detect Alzheimer's disease correctly 86 per cent of the time.
The proposed new test could have many advantages, including being "quick and easy to administer, relatively inexpensive and readily available", she said.
Some other markers of early Alzheimer's disease had been previously known, but related testing involved costly or invasive and more time-consuming procedures that could not be used in routine clinical practice, she said.
If a GP took a blood sample from a patient starting to experience memory loss, researchers would analyse the blood and see its microRNA compared with "established patterns".
Study participants included about 50 Otago people whose diagnosis with Alzheimer's disease had been confirmed in Dunedin by consultant neurologist Dr Nicholas Cutfield and clinical psychologist Professor Bob Knight. Otago Daily Times