My last post was a five part essay on the NASA Twins Study. It dealt with differences in biomarkers between a pair of twins, one of which was in Earth orbit and the other was on the ground. Recently, there has been interest in old research in blood chemistry.
An international team of researchers has found new biomarkers that can be used for diagnostic purposes. They will also be useful as predictive tools of the risks associated with deep-space flight. The research team included three researchers from the Lawrence Livermore National Laboratory (LLNL). They examined twenty-year-old blood samples from space shuttle astronauts before and after flights. Their findings have been published online in the journal Frontiers in Genetics.
Matt Coleman is a LLNL biomedical scientist in the Biology and Biotechnology Division. He said, “We knew that nucleic acid within exosomes can be intact for 15-20 years, but we weren't sure how space travel would affect them and whether we would find intact exosomes containing nucleic acids in the two-decade-old blood from space shuttle astronauts that was stored away," said LLNL biomedical scientist Matt Coleman, of the Lab's Biology and Biotechnology Division. This is an amazing surprise that we're getting so much information about the RNA in the exosome, the different types of RNA encapsulated within the exosomes and information about the genes and biological processes they regulate.”
Exosomes are small extracellular lipid-protein spheres that transport other molecules. They allow cells and tissue to communicate with each other. Long non-coding RNA (lncRNA) turns controls and turns on cell mechanisms. They can be found in exosomes along with other types of RNA.
In addition to the three researchers from the LLNL, the team also included scientists from the Icahn School of Medicine at Mount Sinai (New York), the University of Virginia School of Medicine, the University of California, San Diego, Ohio State University Wexner Medical Center and The Institute of Molecular Biology based in Yerevan, Armenia.
Coleman added that “Space changed the RNA within the exosomes of the astronauts who went into space. They had signatures that they were astronauts; they had been in a reduced-gravity environment and exposed to doses of space radiation.”
In the research, the team found twenty-seven different expressed lncRNAs, or biomarkers for spaceflight, that changed between pre-spaceflight and after flight. Coleman noted that “When we compare before and after space travel, we see a change in the amount of lncRNA—either more or less—and those changes directly affect the genes that are turned off or on in important cellular functions associated with neurodegeneration, general health and cardiovascular disease.”
The team analyzed RNA isolated from exosome samples of blood that4 came from eighteen space shuttle astronauts between 1998 and 2001. Three of the astronauts were extremely robust. Blood samples were drawn ten days before the astronauts went into orbit. Additional blood samples were drawn three days after they returned from orbit.
Coleman said, “Because the lncRNA can modulate a large number of genes, understanding those genes and the pathways they're associated with—such as general health or cardiovascular disease—would allow us to identify who needs to get specific medicine, change their diet or get more exercise to ward off any negative effects of spaceflight. These kinds of studies are trying to fill the knowledge gaps to first understand the effects of working and traveling in low-Earth orbit and then of deep space on the human body.”
Nearly all the past studies have focused on the effects of space on astronauts in low-Earth orbit. These included shuttle astronauts working on the International Space Station. Coleman said, “As we move to traveling to the moon and Mars, the space environment is going to be dramatically different. There will be greater exposure to ionizing radiation and astronauts will be in space for longer periods with greater times of confinement and extended problems with gravity.”
The LLNL capabilities that aided the team’s study included thirty years of expertise in genomic science, DNA repair as well as researching the effects of ionizing radiation through sequencing for the Human Genome Project. In addition to Coleman, biomedical scientist Amy Sebastian and graduate student Angela Evans from the LLNL took part in the study. The research was led by David Goukassian of the Cardiovascular Research Center at Icahn School of Medicine at Mount Sinai in New York City.
While the team’s current research focuses on lncRNA, the scientists expect to publish three more papers over the next three to six months about other types of RNA identified within exosomes that also play a role in health and diseases. These could furnish more information about the risks associated with spaceflight.