Our blood can tell all kinds of stories related to our health. It can track hormones and blood sugar and whether we have an infection. When our cells die, it’s where fragments of our cell-free DNA are cast adrift. That DNA is a diagnostic tool of its own, and it’s becoming clearer and clearer how useful it can be (https://longevity.technology/news/mitochondrial-dna-fragments-in-blood-shown-to-be-important-biomarkers-for-aging/).
It starts before we’re born, with prenatal screenings for various genetic disorders. If you develop certain types of cancer, cell-free DNA can be a useful monitoring tool. Now it also seems that it can serve as a marker for inflammation, one of the key signs of aging and an early warning system for all kinds of other health problems.
Research has been carried out into the relationship between cell-free DNA and aging before, but this was the first time a study focused on mitochondrial DNA, which we inherit through our mothers, in particular. Researchers from Johns Hopkins analyzed blood samples from 672 participants, all enrolled through other studies at the RUSH Alzheimer’s Disease Center. Participants were all over 80, but the samples had been taken back in the 1990s.
The scientists were looking at four inflammatory markers: cytokine proteins, inflammatory liver proteins and two different tumor necrosis factors. These were compared to the amount of short and long fragments of what’s known as CCF-mtDNA. Short fragments are what’s left over after a cell’s natural death, when functions like replication no longer work. Long fragments occur after major events, such as disease or injury, cause the rapid death of the cell. Sometimes the body reacts to large DNA fragments in the same way it would a bacterial or viral threat, by triggering an inflammatory immune response.
Inflammatory biomarkers were present in higher levels when CCF-mtDNA was also high. While cell-free DNA was generally associated with physical and mental deterioration, mitochondrial DNA specifically only appeared to correlate with physical decline. Every participant went through physical tests, such as grip strength and fatigue, as well as cognitive tests, including memory and perception, when their sample was taken.
Improved understanding of aging, including the significant role of inflammation, will hopefully help us develop ways to stay healthier for longer. Scientists hope they can expand their research to more people and further explore how inflammation may be triggered or aggravated by cell-free DNA fragments.