Alzheimer's disease is difficult to detect in its early stages, and is often diagnosed only after it begins deteriorating someone's memory and thinking abilities.
Researchers around the world have been looking at ways to improve the way Alzheimer's disease is diagnosed. While lots of research is focused on the brain, there could also be clues in your bloodstream as to how the disease manifests – possibly in the form of trace metals.
A team of researchers from the University of Technology, Sydney (UTS) Faculty of Science in Australia have taken the approach of scouring the blood for possible early warning signs, and are now closing in on a disease indicator for Alzheimer's. Their suspected culprit: iron.
Specifically, the team is studying a protein called transferrin, which helps shuttle iron around the body. Iron binds to the transferrin proteins in your blood. When these proteins encounter corresponding transferrin receptors on the surfaces of cells, the iron is then transferred to those cells.
If transferrin fails to do its job, so to speak, iron that was meant to be distributed throughout the body might end up accumulating in the brain. According to the UTS:Science press release, this accumulation "contributes to the build-up of 'plaques' and 'tangles'. Plaques impede the transmission of signals among brain cells and tangles kill them."
The research is led by neurochemist Dominic Hare from UTS:Science and Blaine Roberts from the Florey Institute in Melbourne, Australia, who investigates the way trace metals move through the blood and influence protein functions. Together they have used blood samples collected for the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL) to carry out an extensive study searching for biomarkers, cognitive characteristics and lifestyle factors that might combine in some way to help indicate the onset of Alzheimer's.
"The unique thing about AIBL is that it's following 1,000 people through time," said Hare in the release. "That gives us statistical power."
The researchers used samples from 34 AIBL participants – who are all being tracked for more than four years - and samples from 36 healthy participants, and analysed their blood with specialised mass spectrometry equipment, which allowed them to detect minuscule concentrations of trace metals.
Their results showed that, overall, participants with Alzheimer's had lower levels of iron in their blood compared to the healthy volunteers.
Interestingly, both groups of participants had the same amount of transferrin in their blood. The key difference, they found, is in how efficiently the transferrin is working. In the blood samples from the participants with Alzheimer's, the transferrin proteins were carrying less iron away from the brain. It's a subtle difference that the researchers say is "not observed through routine pathological testing."
"The disease develops so slowly and has so many effects on the body, being able to separate what's cause and what's effect is a big problem," Hare says in the release. "If we can identify why the disease is happening, we could intervene to alleviate the symptoms and potentially halt the disease process."
"The next step is to look at a copper-binding protein called ceruloplasmin that interacts with transferrin. Putting all these pieces together will help find methods to maintain quality of life, possibly slowing or even halting the progress of the disease."