Scientists have revealed age- and health-related differences in DNA fragments found free in the bloodstream called cell-free DNA (cfDNA).
cfDNA refers to naked fragments of DNA which occur in the bloodstream. The recent research was considered to test whether variations in these fragments could be used to guess a biological age. That may describe an individual’s functional position instead of their chronological age.
This research, published in the journal Aging Cell, revealed many interesting findings. In the research, samples of cfDNA were taken from three groups of individuals;
• those in their twenties
• those in their seventies
• those over one hundred years of age. The individuals in this group were further subdivided into healthy and unhealthy.
Outcomes of the research
The outcomes of the research exposed differences in the nucleosome spacing of cfDNA. It varied depending on a person’s status of age and health. The nucleosome spacing of the cfDNA was consistent in the participants in their twenties.
But the spacing declined with age, becoming least consistent in the unhealthy centenarian group. Another finding was the likeness between the spacing of nucleosomes in the healthy and youngest group, instead of with the group in their seventies.
These differences propose that healthy aging marks in epigenomic features similar to those of younger persons. Its reasons are unclear, as many aspects take part in epigenomic changes, just as with all factors of age-related variations.
The cfDNA testing is designed at providing an improved understanding into epigenetic fluctuations and their significance.
The researchers used next-generation sequencing with sophisticated computational analysis to re-form the nucleosome spacing across various genome regions. This comprised both heterochromatin and euchromatin regions.
The main researcher Nicola Neretti said, “cfDNA is rather like a message in a bottle which captures what the cell looked like, epigenetically talking before it died”. The cellular components in maintaining regular nucleosome spacing degenerate with age.
The changes in spacing, therefore, reflect this deterioration, instead of being the consequence of the movement of the nucleosomes themselves or increases in their density.
Conversely, when nucleosome positioning varies, different genomic parts become more or less accessible. This degrades the working of these components. One illustration is the release of normally immobile segments of DNA called transposons.
The current research exposed that cfDNA signals decrease with advancing age at the start of two normally seen transposons. The interpretation could be that unhealthy participants, along with people in their seventies, have more mobile transposons. Therefore, these replicate themselves into the genome. Thus, disrupting normal genetic procedures.
The present research observed cfDNA from only 12 persons from Bologna, with three focuses in each age group. To correlate biological age with epigenetic signs, a much larger model will be required.
The best method, Neretti thinks, would be to observe cfDNA from a large population of persons over 2 or 3 decades. This would allow chasing of the age-related epigenomic changes happening in each individual’s DNA, in addition to the rate of such alterations.
Studying many individuals could make it probable to discover links between epigenomic differences and the individual’s diet, lifestyle, or medical conditions.
Better considering the epigenetic variations of the aging course could help in evolving treatments for age-associated ailments. And someday it could be used to determine whether your body is aging faster or slower than typical, Neretti added.