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Part 3 of 5 Parts (Please read Parts 1, 2 and 3 first)
#6 – Space affects the microbiome
There is a vast community of microorganisms in the human gut. This is called the microbiome. It plays a very important role in our overall health. In order to study how living in a microgravity environment impacts the microbiome, Fred Turek of Northwestern University monitored the state of each of the Kelly twin’s microbiome before, during, and after Scott’s yearlong mission on the ISS. The research team found that the microbiomes of both Scott and Mark were drastically different at all times throughout the project. These differences were somewhat expected considering that microbiomes are very sensitive to environmental variances such as diet and individual immunity. However, the researchers state that Scott’s microbiome was different in space than it was in preflight. It displayed a decreased presence of one branch of bacteria called Bacteroidetes. These changes did not continue after Scott returned to Earth. While the study showed that Scott’s microbiome changed when switching between orbit and Earth, the changes were similar to those that would be expected if someone on the ground significantly changed their diet or was exposed to a new environment.
#7 – Spaceflight can trigger gene mutations
Chris Mason of Weill Cornell Medicine used the Twins study to investigate how space travel can influence genetics. His team used whole-genome sequencing to look for chemical changes in RNA and DNA. They were able to show that Scott experienced hundreds of unique gene mutation when compared to his twin. Some distinct gene mutations were expected but the sheer number of changes surprised the researchers. A few of these gene changes were discovered only after Scott returned from orbit. They were found on cell-free DNA and RNA that was circulating in his bloodstream. The researchers believe that these gene changes were caused by the stresses of space travel which can alter the biological pathways within cells, causing them to eject DNA and RNA. The free-floating DNA and RNA molecules can then trigger the production of new fats or proteins. They can even turn specific genes on or off. Ninety three percent of the genes that had altered expression while in space returned to normal postflight. The researchers found a subset several hundred “space genes” that remained disrupted after Scott’s return from orbit. Of the many gene-induced changes that Scott experienced, the researchers found five to be of particular relevance to future space missions. (1) Scott experienced hypoxia which is a condition caused by a lack of oxygen and a surplus of carbon dioxide; (2) Mitochondrial stress and increased levels of mitochondria in the blood; This suggests that there was damage to mitochondria; (3) Telomeres lengthening, DNA damage and DNA repair increased while Scott was in space. This could be a result of living a healthy lifestyle while constantly exposed to radiation; (4) Collagen production, blood clotting and bone formation all decreased. This was probably due to a combined result of living in microgravity and of fluids shifting around inside Scott’s body; and (5) There was evidence of hyperactive immune activity which might be an effect of living in a new environment. This could also be a result of mutating bacteria.
Please read Part 4 next