Stem cells and aging is a topic that’s all over the board. I recently blogged on the subject with a focus on fat stem cell injections. One of the pressing issues to consider is how age impacts the DNA of old stem cells. A new study shows that there may be less to worry about than previously thought as stem cell DNA repair may save the day.
As we age, our DNA strands get broken. DNA is the blueprint of life, so this is about as helpful as spilling ink all over the only copy of the building plans-the resulting construction job can be negatively impacted. The DNA breaks due to radiation and chemical exposure and these strand breaks accumulate with age-meaning a younger person generally has fewer and an older person more. For a stem cell, this DNA damage can be a big issue. This is because the blue print of how it should help repair the body or which cell to turn into to replace a damaged cell could be impacted.
This new study looked at mouse blood forming stem cells known as Hematopoietic stem cells (HSCs). These maintain homeostasis and regenerate the blood system throughout life. In our body we have quiescent stem cells (hibernating) that act as a reserve pool of cells. So if all of your active stem cells get used up in a big injury, this reserve supply can be called to “active duty”. In the study, the authors found, as expected, that older animals had HSCs that were ridden with accumulated DNA damage. However, once these cells were called from the reserves to active duty, the body did a good job of repairing this damage.
The upshot? While accumulated DNA damage is a big deal for stem cells, our bodies seem to have found a way around this issue. We can repair this damage in reserve stem cells, which is a good thing!