How is the health of astronauts effected by their time spent in outer space?

NASA utilized a twin study to understand the impact that outer space has on an astronaut. Scott and Mark Kelly were the two subjects in the study. Scott spent 1 year in space while Mark stayed on Earth. The teams studied the physiology, memory, and genes of the twins. They recorded them at 3 different points of the study. They recorded them before, during, and after the yearlong study. 

            The results of the study have not been made fully available to the public, but NASA has given some tidbits. They allude to the time in space having an impact on stressors (Rehm, 2019). These stressors can then impact the genes of the individual. The genes are not changed, they are manipulated. This type of genetics is called epigenetics which means on the genome. The epigenetic changes can consist of histone modifications such as acetylation(loosening) or methylation (tightening) of the DNA. These changes are inheritable (Heath, 2018). The genes can cause cognitive function to falter. Scott’s genes had a harder time regulating repair of DNA. Telomere length was affected as well. Telomeres are on the end of the DNA and act as a cap on the end of the DNA. The telomeres are important for the lifespan of a cell (Shammas, 2012). Scott’s were longer during flight, then were normal after 48 hours after flight. They then were shorter months later (Rehm, 2019). 

            Scott Kelly’s chromosomes were altered structurally that could lead to types of infertility or cancer. Most of his genes reverted back to a relative normal after 6 months but 9 percent remained in the state that they were in space (Rehm, 2019). 

A flaw that could be identified in the study was the fact that both brothers were astronauts and had both spent time in space. I believe that the ideal study would have had one brother who had never been to space and one who had. As a limitation of this study there is a challenge in finding an astronaut with a n identical twin.

            Future studies could include the long-term effects of outer space on health. It would be beneficial to know what the 9 percent of Scott Kelly’s genes that remain in space mode will do and how it will impact his health.

References

Heath, Katy, and Amy Marashall-Colon. “Epigenetics.” UIUC Genetics Lecture. UIUC Genetics Lecture, 15 Oct. 2018, Champaign- Urbana, UIUC.

Rehm, Jeremy. “NASA's Twins Study Reveals Effects of Space on Scott Kelly's Health.” Science News, Science News, 8 Aug. 2019, www.sciencenews.org/article/nasa-twins-study-reveals-effects-space-scott-kelly-health.

Shammas MA. Telomeres, lifestyle, cancer, and aging. Curr Opin Clin Nutr Metab Care. 2011;14(1):28–

34. doi:10.1097/MCO.0b013e32834121b1