Age can be determined by blood

It turns out that the aging process is visible even in the very basis of our organism – in the blood. Every year, the blood renewal system loses diversity: instead of thousands of active stem cells, only a few dominant cells come to the forefront. These “leaders” replace the rest, but with it the immune system’s resistance to stress and infections decreases.

A team from Barcelona, bringing together specialists from the Center for Genomic Regulation and the Institute for Biomedical Research, has developed a technology that allows you to “read” the history of each blood cell. The secret lies in the marks on DNA that remain after cell division. These marks are like barcodes: they can be scanned and found out from which stem cell a particular group of cells came.

Using this approach, scientists have shown that already by the age of 50, the diversity in blood stem cells is markedly reduced. After 60 years, almost the entire blood renewal system works at the expense of a few large clones. Moreover, this process is not accidental – it develops gradually and is almost inevitable.

It is important that these changes occur not only in mice, on which usually test hypotheses, but also in humans. This means that the loss of diversity in stem cells is a basic part of biological aging. That said, a fraction of the “influential” clones did find mutations associated with an increased risk of heart disease, stroke or blood cancer. But most of these clones were completely “clean,” suggesting that the growth of some and the “dropping out” of others is a natural process, not always associated with disease.

The technology, called EPI-Clone, requires no intervention in genes and works with what is already in the body. This makes it particularly valuable: it is now possible to observe the aging of a person’s blood without complicated and expensive procedures. Perhaps in the future, doctors will be able to notice in advance when stem cells are losing diversity and intervene in a timely manner.

Another observation concerns which cells begin to predominate with age. Many have been found to produce predominantly myeloid cells, a type of immune cell associated with chronic inflammation. This is what many experts believe underlies age-related diseases. In experiments on mice, removing such cells helped restore a more “youthful” blood composition. Perhaps in the future, a similar approach will be applicable to humans.