Can cellular ageing be rewound? In the lab, at least in part, yes. A new study from the University of Bonn has turned blood cells from an 80-year-old person back to a biological age of under 20.
The result helps us understand how cells age. It also shows what time leaves written for good: a question that closely concerns anyone who chooses to store their baby’s cells at birth.
What the University of Bonn study shows
The team led by Oliver Brüstle at the University Hospital Bonn published the study in Aging Cell (Berg et al., 2026), together with RWTH Aachen University. The results were presented in a University of Bonn press release.
The researchers took blood cells from donors of all ages, from newborns to older adults. They then converted them directly into neural stem cells, which can give rise to neurons.
During the conversion, the cells’ biological age dropped sharply: cells from an 80-year-old donor reached a molecular age of under 20. According to the study, around 13% of the donor’s age remained in the early stages of culture and around 5% in the later stages.
The process was slow and could be observed for more than 100 days. This, the authors explain, makes it a good model for studying cellular ageing and the substances that speed it up or slow it down.
Cellular ageing: what the epigenetic clock measures
A cell’s biological age is measured with epigenetic clocks. They read small chemical marks that build up on DNA over time and that determine which genes are read.
These marks do not change the DNA sequence, that is, the “letters” of the genetic code. That is why reprogramming can rewrite them. This also happens when cells are turned into iPSCs, pluripotent cells from which almost any type of cell can be obtained: along this route, rejuvenation was already known, and it is fast.
For Brüstle, the topic is central to neuroscience, because age is the main risk factor for neurodegenerative diseases such as Alzheimer’s.
What time does not erase: DNA mutations
Cellular ageing does not only leave epigenetic marks. Over the years, DNA also accumulates mutations, small errors in the sequence, and reprogramming does not correct them.
From birth onwards, blood stem cells acquire on average around 17 new mutations per year (Mitchell et al., Nature 2022). And reprogrammed cells keep them: iPSCs derived from the blood of donors in their late 80s carried about twice as many mutations in coding genes as those from donors in their 20s (Lo Sardo et al., Nature Biotechnology 2017).
In short: reprogramming turns back the clock, not the DNA.
Why cells collected at birth are a unique starting point
If mutations build up over the years, cells collected at birth are the ones that have had the least time to accumulate them. This is one of the reasons why research is also looking at cord blood as a source for reprogramming.
Cord blood cells can be reprogrammed into iPSCs, even with just two factors (Giorgetti et al., Nature Protocols 2010). In a study published in PLoS ONE in 2013, cord blood iPSCs carried on average about one mutation in coding genes per cell line, and the authors described cord blood as an ideal source for iPSC banks.
These are areas of research and clinical trials, not yet standard therapeutic practice. But they explain why cellular ageing makes the moment of birth so valuable: it is the only opportunity to store cells this young.
With MyBabyCells, SSCB stores cord blood in Switzerland, in a biobank with FACT-NetCord accreditation and GMP certification. For adults, SSCB stores peripheral blood mononuclear cells (PBMC) through EternaCell’s MyCells service.
Would you like to know how to store your baby’s cells at birth? Discover MyBabyCells or contact us.
FAQ
What is cellular ageing?
It is the set of changes that time leaves in cells. One part concerns epigenetic marks, which regulate which genes are read. Another part is the mutations that accumulate in the DNA sequence.
Can cellular ageing be reversed?
In the lab, partly yes: reprogramming rewrites epigenetic marks and turns back the biological age of cells. DNA mutations, however, remain. The Bonn study concerns cells in a dish, not people.
What is the epigenetic clock?
It is a method that estimates a cell’s biological age by reading the chemical marks on its DNA. The result can differ from chronological age.
Why does cellular ageing make the moment of birth important?
Because cells collected at birth, such as cord blood cells, have had less time to accumulate mutations. That is why research considers them a good starting point for reprogramming.
Can cord blood become iPSCs?
Yes, in the lab cord blood cells can be reprogrammed into iPSCs. This is a field of research: iPSC-based therapies are still in clinical trials.
Does cellular ageing depend only on age?
Age is the main factor, but research is also studying which substances and conditions speed up or slow down the signs of age in cells. This is exactly what the Bonn model was designed for.
Sources
- Berg L. J. et al., Protracted Fate Acquisition and Epigenetic De-Aging During Induced Neural Stem Cell Conversion of Human Blood Cells, Aging Cell 2026
- University of Bonn, Researchers Transform Old Blood Cells into Young Brain Cells, 9 October 2026
- Mitchell E. et al., Clonal dynamics of haematopoiesis across the human lifespan, Nature 2022
- Lo Sardo V. et al., Influence of donor age on induced pluripotent stem cells, Nature Biotechnology 2017
- Giorgetti A. et al., Generation of induced pluripotent stem cells from human cord blood cells with only two factors: Oct4 and Sox2, Nature Protocols 2010
- Few Single Nucleotide Variations in Exomes of Human Cord Blood Induced Pluripotent Stem Cells, PLoS ONE 2013
