Blood donation is an important way to support community health. A consistent, reliable and safe blood supply is necessary for providing proper healthcare to trauma victims, surgical support, and other critical applications. Scientists have now found that donating blood may stimulate beneficial genetic changes. Frequent blood donors were found to carry mutations in blood stem cells that boosted the growth of healthy new cells that were not cancerous. The findings have been reported in the journal Blood.
As people get older, mutations naturally build up in blood stem cells. Groups of blood stem cells or clonal groups of cells may emerge that carry similar mutations. These mutations may sometimes lead to cancer. This work may help show how to reduce the likelihood of those mutations, since the bone marrow of frequent blood donors generates new blood stem cells, and while mutations occur they are not related to cancer.
In this study, the researchers assessed blood samples collected from more than 200 individuals who had each donated blood more than three times per year for over 40 years. They also analyzed a control group, in which people had sporadically donated blood fewer than five times in their lifetimes.
There was a similar level of genetic or clonal diversity among blood stem cells in both frequent and rare donors. There were mutations in a gene called DNMT3A in both groups, for example. This gene has previously been linked to leukemia development. But the frequent donors carried mutations that are not related to cancer.
The investigators modeled the DNMT3A mutations found in both groups of donors in human cell lines, and then either boosted red blood cell production with erythropoietin (EPO) or mimicked an infection with inflammatory molecules. The cells carrying mutations of frequent donors did not grow in the inflammatory conditions, but did grow when exposed to EPO. But in rare donors, the opposite was seen.
The mutant human blood stem cells were also transplanted into a mouse model, and blood donation was mimicked. Mice carrying stem cells with frequent donor mutations were able to produce blood cells and grow normally. None became cancerous. But the transfer of rare donor stem cells triggered a significant increase in white blood cell production in the mice.
The study authors suggested that regular blood donation leads to the selection of mutations in blood stem cells that will respond well when under stress. Stem cells carrying mutations that are linked to blood cancer are also not selected.
“Our work is a fascinating example of how our genes interact with the environment and as we age," said senior study author Dominique Bonnet, Group Leader of the Haematopoietic Stem Cell Laboratory at the Francis Crick Institute.
Since only a small group of people were assessed in this study, the researchers noted that this work will have to be confirmed in larger groups to truly show that blood donation will help reduce the incidence of mutations that lead to blood cancers.
Sources: Francis Crick Institute, Blood
