How blood stem cells can be rejuvenated

Now for the first time, a research team at Lund University in Sweden has succeeded in rejuvenating blood stem cells with established reduced function in ageing mice. 

When we are young, our blood stem cells produce an even and well-balanced number of red and white blood cells according to need. As we age, however, the capacity of the blood stem cells to produce the number of blood cells we need declines.

Tracking old stem cells

A fundamental question was whether blood stem cells age differently within a single individual or whether all blood stem cells are equally affected by advancing age.

In an initial stage, it was therefore important to genetically mark old blood stem cells, to enable the identification and tracking of those most affected by age. In the next step, these traceable cells were reprogrammed to another type of stem cell – known as iPS cells, which can generate all cells in an individual and not only blood cells.

When the cells are reprogrammed, their identity is ‟re-set” – when these reprogrammed iPS cells formed new blood stem cells, the researchers observed that the re-set had entailed a rejuvenation of the cells.

Not caused by mutations

The research team’s studies have also thereby shown that many age-related changes in the blood system cannot be explained by mutations in the cells’ DNA. If the changes depended on permanent damage at the DNA level, the damage would still be present after the re-set. Instead, epigenetic changes appear to underlie the decline in function associated with advancing age.

“Our findings justify further research to improve the function of human blood stem cells and thereby address diseases such as anaemia, leukaemia and other blood disorders”, concludes David Bryder.

The research was funded by: the Swedish Cancer Society, the Swedish Research Council, the Swedish Pediatric Leukemia Foundation, Knut and Alice Wallenberg foundation, ERC consolidator grant.