Scientists at the University of Bonn in Germany have found a way to make human cells display biological characteristics associated with much younger cells, with those derived from an 80-year-old donor showing an epigenetic age below 20. The findings, published in the journal Aging Cell in 2026, could help researchers understand how age-related changes occur and whether some of them can be reversed.According to the research, announced on October 9, scientists converted blood-cell precursors from an elderly donor into neural stem cells using specialised proteins called transcription factors. These stem cells can develop into nerve cells and provide researchers with a model for investigating age-related changes in the nervous system.The study’s notable finding was not just the apparent rejuvenation of the cells, but also the time it took for the changes to occur. Rather than producing the transformation rapidly, the researchers observed the process unfolding over more than 100 days.
Cells showed an epigenetic age below 20
Biological age does not always correspond to the number of years a person has lived. Scientists can estimate a cell’s biological age by examining epigenetic markers, chemical modifications to DNA that influence how genes function.In the Bonn study, cells derived from an 80-year-old donor displayed epigenetic characteristics associated with cells younger than 20. The findings suggest that the cellular reprogramming process can substantially alter molecular markers linked to aging.Professor Oliver Brustle, director of the Institute of Reconstructive Neurobiology at University Hospital Bonn, said the changes extended beyond measurements of biological age.“We also know that this epigenetic rejuvenation ensures that the cells actually behave like young cells,” Brustle said.The observation is significant because researchers want to understand whether changes in epigenetic age correspond to meaningful differences in how cells function.
Reprogramming process unfolded over more than 100 days
Earlier approaches to cellular reprogramming have often involved converting mature cells into pluripotent stem cells before directing them to develop into another specialised cell type. Such methods can produce substantial changes in cellular identity and age-associated markers over a relatively short period.The Bonn team used a different approach, directly reprogramming blood-cell precursors into neural stem cells. This allowed the researchers to observe the gradual changes without first passing through the pluripotent stem-cell stage.The process unfolded over more than 100 days, offering scientists an opportunity to study how epigenetic changes develop over time.Brustle said the slower transformation could help researchers identify the factors and substances that influence cellular rejuvenation. By examining the process as it happens, scientists may be able to investigate which changes are essential, which can be interrupted and how different stages relate to the cells’ eventual characteristics.
Findings could help research into Alzheimer’s and other neurological conditions
Neural stem cells can generate nerve cells, making them useful for laboratory studies of the nervous system. Researchers hope the approach could help them investigate how aging affects neural cells and contribute to research into age-related neurological conditions, including Alzheimer’s disease.A model that captures aspects of cellular aging may help scientists study disease mechanisms and test research hypotheses under controlled laboratory conditions. It could also provide a way to examine whether particular interventions influence age-associated molecular changes.However, the study does not establish that the method can prevent or treat Alzheimer’s disease. Further research would be needed to determine how the findings translate to disease models and, eventually, potential clinical applications.
Cellular rejuvenation is not the same as reversing human aging
Despite the striking result, the findings should not be interpreted as evidence that scientists have reversed aging in a person. The researchers studied cells under laboratory conditions; they did not make an 80-year-old person biologically younger, demonstrate an increase in life expectancy or develop an anti-aging treatment for patients.An epigenetic age estimate is also only one measure of biological aging. It does not, by itself, establish that every aspect of a cell’s function or health has returned to a younger state.The research offers a model for examining how cells change during reprogramming and may help scientists investigate the mechanisms underlying cellular aging. Whether these findings can eventually inform therapies for age-related diseases remains an open question.For now, the study represents a development in laboratory research into cellular rejuvenation, rather than a proven method of reversing aging in humans.
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