Astronaut blood reveals genetic mutations for cancer and heart disease

Could just be a coincidence ... let's keep going into space and see what happens

Analyses of blood taken before and after spaceflight have confirmed astronauts undergo genetic mutations that could make them more susceptible to developing cancer and heart disease.

Cell functions can change due to alterations in DNA brought on by environmental factors. These genetic mutations, known as somatic mutations, can occur from exposure to things like radiation or hazardous chemicals. Scientists can identify somatic mutations by studying changes in blood cells, and some of these mutations are signs of clonal hematopoiesis, a process where the body starts making more and more cells carrying the same genetic mutation. 

Clonal hematopoiesis is often linked with aging, smoking, and carries a higher risk of cardiovascular problems and blood cancer.  A team of researchers led by the Icahn School of Medicine at Mount Sinai, a private medical school in New York City, decided to study astronauts' risk of developing clonal hematopoiesis. 

David Goukassian, professor of medicine with the Cardiovascular Research Institute at Icahn Mount Sinai and lead author of the study published in Nature Communications Biology, explained in a statement on Wednesday: "Astronauts work in an extreme environment where many factors can result in somatic mutations, most importantly space radiation, which means there is a risk that these mutations could develop into clonal hematopoiesis.

"Given the growing interest in both commercial spaceflights and deep space exploration, and the potential health risks of exposure to various harmful factors that are associated with repeated or long-duration exploration space missions, such as a trip to Mars, we decided to explore, retrospectively, somatic mutation in the cohort of 14 astronauts."

Goukassian and his team obtained blood samples from astronauts before they were sent into space, and then for three days after they landed back on Earth during 1998 to 2001. They found that all 14 astronauts had at least one genetic mutation, five had two or more. DNA sequencing showed a total of 34 mutations in 17 genes associated with clonal hematopoiesis.

The most frequent mutation was in TP53, a gene that produces a protein involved in suppressing tumor growth, and in DNMT3A another gene related to acute myeloid leukemia. The team believe the damage in DNA could be due to spaceflight, although they don't have enough evidence to confirm their suspicions.  

"It is too soon to attribute any of these mutations to spaceflight, however, we were surprised to find that the DNA damage repair gene TP53 was the most frequently mutated in this astronaut cohort, [where the median age was] 44 years, reflecting a potential difference compared to the civilian population, as well as based on current clinical evidence somatic TP53 mutations are uncommon in patients without a history of cancer radiotherapy," Goukassian told The Register

The team hopes that NASA will screen astronauts for somatic mutations every three to five years to build a bank of samples for scientists to study. In the future, NASA could use the data to understand and figure out which astronauts may be more susceptible to genetic mutations and use it to calculate individual risk. 

Protection against DNA damage may not be possible if it is due to the harsh environment of space, Goukassian said. "Identification of individual susceptibility and monitoring possible clonal expansion or maybe regression of clonal hematopoiesis will allow early intervention to reduce or prevent the risks of disease development in astronauts," he concluded. ®

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