Iron in the brain may play an important role in the development of Alzheimer’s disease, research has shown.
The findings suggest that lowering iron levels, possibly with a drug, could delay progression from mild loss of memory and thinking ability to Alzheimer’s.
But experts said the evidence was not strong enough to support the idea of a diagnostic iron test for individuals at risk of the disease.
Scientists measured levels of ferritin, an iron storage protein, in the cerebrospinal fluid (CSF) of 302 people in their seventies.
They found that higher amounts of iron predicted poorer mental performance in healthy participants, those with mild cognitive impairment (MCI) and Alzheimer’s patients.
Higher ferritin levels were associated with speedier progression from MCI to Alzheimer’s.
Reporting their findings in the journal Nature Communications, the researchers led by Dr Ashley Bush, from the University of Melbourne in Australia, wrote: “Lowering CSF ferritin, as might be expected from a drug like deferiprone, could conceivably delay MCI conversion to AD (Alzheimer’s disease) by as much as three years.”
The research also linked raised brain iron levels to the gene variant APOE-4, which increases the risk of Alzheimer’s.
People with the gene were more likely to have higher levels of ferritin in their brains.
“These findings reveal that elevated brain iron adversely impacts on AD progression and introduce brain iron elevation as a possible mechanism for APOE-4 being the major genetic risk factor for AD,” the scientists wrote.
Dr James Pickett, head of research at the Alzheimer’s Society in the UK, said: “Previous evidence suggests that an imbalance in iron in the brain may be linked to Alzheimer’s disease. This interesting study adds to these findings.
“The study, using seven years’ worth of data, finds that higher levels of the iron storage protein ferritin may be associated with people with mild cognitive impairment going on to develop Alzheimer’s disease earlier.
“The biggest mistake we could make would be to take these results as meaning that a test for conversion from mild cognitive impairment to Alzheimer’s disease is around the corner.
“It’s not clear enough from this study whether iron levels could be used to predict this conversion with enough accuracy and we can’t draw any conclusions about whether we might be able to use iron as a target for future treatments.
“We need to see much more research into areas such as this, which is why Alzheimer’s Society has pledged £100m for dementia research in the next ten years.”
Dr Eric Karran, research director at the charity Alzheimer’s Research UK, said: “Understanding the processes that underlie the progression of memory and thinking problems in old age is a key goal of dementia research.
“While this study adds to existing evidence suggesting that iron plays an important role in Alzheimer’s disease, it doesn’t provide a test that would be useful in the clinic.”