Rejuvenating Blood of Mice by Reprogramming Stem Cells That Produce Blood

The blood of young and old people differs. In an article published recently in the scientific journal Blood, a research group at Lund University in Sweden explain how they have succeeded in rejuvenating the blood of mice by reversing, or re-programming, the stem cells that produce blood.

"Our ageing process is a consequence of changes in our stem cells over time," explained Martin Wahlestedt, a doctoral student in stem cell biology at the Faculty of Medicine at Lund University, and principal author of the article. "Some of the changes are irreversible, for example damage to the stem cells' DNA, and some could be gradual changes, known as epigenetic changes, that are not necessarily irreversible, even if they are maintained through multiple cell divisions. When the stem cells are re-programmed, as we have done, the epigenetic changes are cancelled."

Even if the composition of the blood in old and young mice is remarkably like that in young and elderly people, Martin Wahlestedt stressed that the science is still only at the stage of basic research, far from a functioning treatment. The research group is pleased with the results, because they indicate that it may not primarily be damage to DNA that causes blood to age, but rather the reversible epigenetic changes.

"In older people, the number of B- and T-lymphocytes falls, while the number of myeloid cells increases," said Martin Wahlestedt. When an elderly person is affected by leukemia, the cancer often has its origin in the myeloid cells, of which the elderly have more. Being able to 're-start' the blood, as Martin and his colleagues have done in their studies on mice, therefore presents interesting possibilities for future treatment.