German Scientists Rejuvenate Cells of 80-Year-Old by Over 60 Years

Specialists from the University Hospital Bonn and the University of Bonn have transformed blood cells from an 80-year-old donor into neural stem cells with a molecular age of less than 20 years: in laboratory conditions, the cells "shed" more than six decades of biological aging. The results were published in the journal Aging Cell.

The scientists reprogrammed immature erythrocyte precursors into neural stem cells, from which brain cells can develop over time. During the transformation, molecular markers of aging were almost completely reset. "Using this method, we directly converted erythrocyte precursors into neural stem cells," said Professor Oliver Brüstle, director of the Institute of Reconstructive Neurobiology at the University Hospital Bonn. Previously, the Bonn team demonstrated the approach's effectiveness in animals: nerve cells obtained in this way established connections with existing neurons after transplantation into the brains of mice.

The main difference from previous experiments is the speed of the process. Previously, rejuvenation required two stages: first, the cell was turned into a pluripotent stem cell, capable of giving rise to almost any cell type, and then directed down a narrower path to a neural stem cell. In such a scenario, rejuvenation occurs quickly, and intermediate changes are extremely difficult to trace. The Bonn researchers excluded the pluripotent stage. "In our approach, rejuvenation occurred gradually and could be tracked for more than 100 days," Brüstle explained.

The degree of rejuvenation was assessed using epigenetic clocks—a tool that determines biological age based on chemical modifications of DNA that do not affect the sequence itself. After reprogramming, the cells of the 80-year-old donor exhibited a profile corresponding to an age of less than 20 years. Approximately 50 days later, the molecular age had decreased by about 60 years. "We also know that this epigenetic rejuvenation ensures that the cells truly behave like young ones," the scientist noted.

The extended process opens new opportunities for studying aging: such a model can be used to determine which molecular mechanisms are involved in rejuvenation and which substances accelerate or slow it down. The work is particularly valuable for neurobiology, where aging is closely linked to severe neurological diseases. "After all, age is the most important risk factor for neurodegenerative diseases such as Alzheimer's disease," Brüstle reminded. However, this is not about a therapy capable of rejuvenating a person: scientists have obtained a laboratory tool to study how cells regain youthful characteristics.