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Giving blood regularly may not just be saving the lives of other people, it could also be improving your own blood's health at a genetic level, according to a new study.
An international team of researchers compared samples from 217 men who had given blood more than 100 times in their lives, to samples from 212 men who had donated less than 10 times, to look for any variance in blood health.
While the differences were subtle, the frequent donors' blood was more likely to have beneficial mutations in a gene called DNMT3A. Other mutations in DNMT3A have been previously linked to blood cancer.
"Our work is a fascinating example of how our genes interact with the environment and as we age," says stem cell biologist Dominique Bonnet, from The Francis Crick Institute in the UK.
Blood cells in bone marrow. (Hector Huerga Encabo)Specifically, the team looked at blood stem cells, which produce more blood cells on demand. As we get older, these mechanisms can start to break down, leading to problems with blood cancers such as leukemia.
Blood loss triggers the production of the hormone erythropoietin. In lab tests on blood stem cells treated with erythropoietin, the researchers found those with the DNMT3A mutation produced blood faster than those without the mutation.
This suggests frequent blood loss leads to more production of the mutated blood cells. Research in mice shows the DNMT3A mutation results in healthier blood levels after the stress of blood loss.
"Activities that put low levels of stress on blood cell production allow our blood stem cells to renew and we think this favors mutations that further promote stem cell growth rather than disease," says Bonnet.
A blood cell viewed under an electron microscope. (Hector Huerga Encabo)Donating blood may better train these stem cells to replace blood in the right way. Follow-up tests in mice backed up that idea of boosting regenerative capacity, without introducing potentially harmful genetic mutations.
However, there are limitations to consider. Blood donors are more likely to be healthier anyway (it's a condition of giving blood), so figuring out any additional health benefit is tricky, because it might actually come from being in better shape to begin with.
"Our sample size is quite modest, so we can't say that blood donation definitely decreases the incidence of pre-leukemic mutations," says Bonnet. "We will need to look at these results in much larger numbers of people."
Irrespective of any health benefits – and previous studies have found others – there's an urgent need for blood donors. In the US, someone needs blood or platelets (small fragments in blood) every two seconds. Having healthier blood is an added bonus.
And while we wait for more detailed studies to confirm these findings, the study tells us more about how blood cancers can get started in the first place – particularly why dangerous mutations do and don't develop in response to stress – which then points to potential therapy options.
"We're now aiming to work out how these different types of mutations play a role in developing leukemia or not, and whether they can be targeted therapeutically," says stem cell biologist Hector Huerga Encabo, from the Francis Crick Institute.
The research has been published in Blood.
