Houston, We Have an Eye Problem

Wednesday, September 9, 2020

Image credit: NASA

 

 

 

 

 

 

 

 

 

Duke researchers team up with NASA to explore gene-environment interactions in astronauts 

By Alexis Kessenich

Astronauts on long-duration spaceflights (LDSF) face a number of risks to their health — some more obvious that others — like during dynamic events such as launch and landing. But there are also lesser-known dangers, such as spaceflight-associated neuro-ocular syndrome (SANS), a spectrum of physiologic and pathologic neuro-ophthalmic changes that include swelling of the optic disc, nerve damage and vision impairment.

An astronaut’s susceptibility of developing SANS remains largely unknown, but a team of researchers in the Center for Applied Genomics and Precision Medicine (CAGPM) is on a mission to discover what causes the predisposition. 

The Nutritional Biochemistry Laboratory at NASA’s Johnson Space Center, led by Scott M. Smith, completed preliminary studies and found metabolomics and genetic differences in astronauts who developed SANS. This led to a broader evaluation of genetics, so the team at CAGPM engaged to help.

 

 

Rachel Myers and Ricardo Henao will lead the study’s data science efforts.

“We’re exploring over 80 genes associated with these metabolic pathways and around 500 different genetic variants within those genes,” says Rachel Myers, lead analyst for the study. “Our team will test each to see if one or groups of these variants are associated with SANS.”

The study is comprised of three different cohorts: one pre- and post-spaceflight cohort and two cohorts mimicking SANS and spaceflight environments on Earth. 

For the first cohort, data, such as eye measurements, were collected from astronauts before and after an LDSF. For the second cohort, data will be collected from patients at the Mayo Clinic with polycystic ovary syndrome, which shares some characteristics with SANS. The third cohort is a 30-day head-down tilt bed rest study, which mimics spaceflight environments and has been shown to inflict similar ocular changes.

Because the sample size is so small, and the number of astronauts available to participate is limited, the team will look at ways to combine different variants together and test association with the phenotypes provided by NASA’s preliminary study to see if they can find what causes the predisposition. 

No one has ever looked at the genetic aspect of SANS before. “It’s going to be really interesting to explore non-traditional approaches for genetic associations,” adds Myers.

At the end of the study, the team hopes to have both an understanding of what the genetic landscape of SANS is and a sense of what approaches are going to work for further investigation.

“With a small cohort, we run the risk of finding something that’s completely random,” says Myers, “so we’ll do additional validation after our initial findings before making recommendations.” 

“Ultimately, we’re exploring gene-environment interactions,” adds Geoff Ginsburg, principal investigator on the study. “The astronauts’ exposures in space – from ionizing radiation and microgravity to extreme social isolation – presents an exciting scientific opportunity to understand how this intense and hostile environment interacts with our genomes.”

Myers says after the study the team also hopes to have a new pipeline in the Center for processing sequencing data to get genetic variants, which will help with future studies. 

A solution for these astronauts is hopefully on the horizon. But, for now, the project is one small leap for CAGPM, one giant leap for genetic research!

JSC Initial Findings

Association of Genetics and B Vitamin Status With the Magnitude of Optic Disc Edema During 30-Day Strict Head-Down Tilt Bed Rest
Astronaut ophthalmic syndrome
Genotype, B‐vitamin status, and androgens affect spaceflight‐induced ophthalmic changes
Spaceflight-related ocular changes: the potential role of genetics, and the potential of B vitamins as a countermeasure