Blood levels of ‘free range’ DNA may signal early detection of dementia and frailty

Oct. 12, 2022
Could lead to supportive services and other interventions to plan for, compensate for, or slow down worsening symptoms.

In a long-term prospective study of more than 600 older participants, Johns Hopkins Medicine researchers say they have evidence that higher levels of cell-free DNA circulating in the blood may signal increased risk of chronic inflammation associated with early signs of frailty and dementia.

The findings, published Oct. 11 in the Journal of Alzheimer’s Disease, could advance the search for relatively simple blood tests that detect risk of Alzheimer’s disease and other forms of cognitive decline.

Circulating cell-free genomic DNA, (ccf-gDNA) is a long-identified product of natural cell death in the body. As cells die via apoptosis (programed cell death), the cells shrink, degrade their plasma membrane, and ultimately rupture and release their contents into the body, including DNA fragments. These fragments end up as free-range DNA in the bloodstream.

For the new study, the researchers tested the blood of 631 people with the average age of 79 who showed no cognitive impairment when the study began. Participants received yearly physical and cognitive testing, at the time of each blood draw. Researchers found that during the eight-year study period, higher levels of ccf-gDNA in the blood were associated with increased cognitive decline and worsening frailty.

Johns Hopkins release

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