A team of researchers has identified warning signs in the blood that would indicate impending dementia and has observed that the levels of certain microRNAs (small molecules) are related to the risk of cognitive decline. 

This work, spearheaded by the German Center for Neurodegenerative Diseases (DZNE) and the Göttingen University Medical Center, has been published in the journal EMBO Molecular Medicine.

At the moment, the technique is not suitable for practical use. Scientists now have the goal of developing a simple blood test that can be applied in routine medical care to assess the risk of dementia. 

Prof. Andre Fischer explained in a DZNE statement that: “when symptoms of dementia manifest, the brain has already been massively damaged. Presently, diagnosis happens far too late to even have a chance for effective treatment. If dementia is detected early, the odds of positively influencing the course of the disease increase.”

The biomarker that Fischer and his colleagues have found is based on the measurement of so-called microRNAs in blood, molecules with regulatory properties that influence the production of proteins and, therefore, a key process in the metabolism of all living beings. 

According to him, “there are many different microRNAs and each of them can regulate entire networks of interdependent proteins and thus influence complex processes in the organism. So, microRNAs have a broad impact. We wanted to find out whether there are specific microRNAs whose presence in the blood correlates with mental fitness.”

90% developed Alzheimer’s

In this sense, the team wanted to check if there are specific microRNAs whose presence in the blood is correlated with mental capacity, and through experiments in humans, mice and cell cultures, the researchers identified three of these molecules. 

To do this, they studied data from both young and cognitively normal individuals and older people with mild cognitive impairment.

During their work, they observed that healthy individuals had levels of microRNAs that correlated with mental fitness: the lower the blood level, the better the subjects’ performance on cognition tests. In tests with patients with mild cognitive impairment, the analysis found that in those in whom the blood marker was very high, about 90% developed Alzheimer’s within two years.

“We, therefore, see an increased blood level of these three microRNAs as a harbinger of dementia,” concludes Fischer, who estimates that in humans the biomarker could indicate a future development of the disease in two to five years.

The results of the study were published in the DZNE.

Image Credit: DZNE website

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