Over the past nearly 60 years, fewer than 600 people have flown in space. Of these, only a handful have spent more than 6 months in space. Yet, the studies performed by NASA, Roscosmos, ESA, CSA, JAXA, CNSA and by numerous academic and research centers prove irrefutably that humans come back from long-duration space flights changed. Microgravity is the root cause of many of the symptoms experienced by astronauts – from decreased body mass to altered ocular structure to metabolic changes, and the search is on for ways to mitigate or counter the deleterious effects of microgravity.
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Lower Body Pressure Negative (LBNP) Suit: The adult human body is made up approximately 60% of water, plus an additional 10% of lymph and blood and other fluids. The distribution of fluids in the body is maintained constant by the body’s circulatory system, which is ‘engineered’ by nature to counter the down-pull effect of Earth’s gravity. In outer space, in conditions of microgravity, more fluids tend to accumulate in the upper part of the body, thus increasing the intra-spinal and intra-cranial fluid pressure. The increase in intra-cranial pressure due to the fluid shifts that take place in the human body during prolonged stays in outer space is believed to be a key cause of the Spaceflight-Associated Neuro-ocular Syndrome (SANS), which affects astronauts’ ocular structures and vision, and of other space-related health conditions such as musculoskeletal and cardiac deconditioning.
Starting in the 1970s, Russian cosmonauts were outfitted with a lower body pressure negative (LBNP) suit (also called “Chibis pants”, see photo) – essentially a giant pair of rubber pants with accordion-like articulations – from which air could be sucked out, thus lowering the air pressure within the suit and pooling the fluids from the upper torso to the legs. The suit was one-size-fits-all and allowed the crewmember wearing it to move throughput the station and carry out professional duties.
“It’s the wrong trousers, Gromit, and they’ve gone wrong!”
Chibis decompression suit in the Technikmuseum Speyer.
By 2015, when NASA initiated its investigation into fluid shifts and their association with intracranial pressure and visual impairment, the only LBNP suit on the International Space Station (ISS) was the suit available in the Russian side of the space station. The suit, mounted to the wall and maintained in a stationary position, is used for the daily LBNP measurements and data collection on the ISS.
Researcher Lonnie Petersen, PhD, with the University of California, San Diego, together with Alan Hargens – University of California and Benjamin Levine – University of Texas Southwestern Medical Center at Dallas, have developed and tested a fully mobile gravity suit comprised of flexible pressurized-pants and attached vest. The suit looks much like a regular pair of ski-pants and simulates the effects of gravity through the application of low-level lower body negative pressure. Additionally, the suit induces a ground reaction force at the bottom of the feet and a mechanical load along the entire body axis, to more closely resemble the pressure placed on the human body by Earth’s gravity. The suit is comfortable enough to wear 8-10 hours a day for daily activities and even for exercise.
Cycle Ergometer with Vibration Isolation and Stabilization (CEVIS): As has been drilled into the heads of humans everywhere, a steady dose of physical exercise is essential to one’s physiological and mental health. On the ISS, where aerobic exercise is used as a countermeasure to the harmful physiological effects of exposure to microgravity, daily exercise is literally a life-saver. This is why astronauts on the ISS get a weekly dose of 30 to 90 minutes of biking on the CEVIS system – a computer-controlled bicycle which maintains an accurate workload independent of pedal speed. The CEVIS system is used in aerobic and cardiovascular conditioning through recumbent or upright cycling activities. Its control panel allows the crewmember to set system parameters and to monitor workout indicators such as workload, cycling speed, heart rate, and elapsed time. Workout measurements are then processed and saved for engineering and medical analysis down on Earth.
Pressure-Regulating Goggles: In 2015, the National Space Biomedical Research Institute (NSBRI) Industry Forum launched the ‘Vision for Mars’ Challenge to identify and advance critical medical technologies for ocular health in space. One of the winners of the challenge, Equinox, LLC of Sioux Falls, S.D., founded by Dr. John Berdahl, had developing the Balance Goggles™ – which are eyewear resembling swimming goggles. These goggles provided a gentle push on the exterior of the eye to stabilize the internal pressure within the eye, thus countering the pressure differential that may be causing the visual problems observed in astronauts.
Following in their footsteps, researchers at the NASA Johnson Space Center have performed a small-scale study, published earlier this year in the journal JAMA Ophthalmology, to examine how the combination of exercise and artificially-increased intra-ocular pressure (through the wear of swimming goggles) affects the relationship between the intra-cranial fluid pressure and the intra-ocular fluid pressure. The study monitored 20 healthy men performing low-, moderate- and high-intensity aerobic exercises while maintaining a head-tilt of minus 15 degrees (to simulate the effect of microgravity). Half were given swimming goggles to wear during exercise and the other half were not.
Researcher Jessica Scott, of the Universities Space Research Association in Houston, Texas and her colleagues found that exercise was associated with reduced pressure in the eye, while the use of swimming goggles, on the contrary, was associated with a small increase in pressure attributed to the goggles pressing the skin around the eye. While further research and testing on the ISS are still necessary to prove their long-term efficacy, goggles offer the promise of a safe and inexpensive countermeasure to the negative effects on the eye structure and vision observed in astronauts during extensive space flights.
Microbial Therapy for Astronauts: According to Elisabeth Grohmann, a microbiologist at Beuth University of Applied Sciences Berlin and lead author of a new study on antimicrobial internal surface coatings for the International Space Station (ISS), “spaceflight can turn harmless bacteria into potential pathogens. Just as stress hormones leave astronauts vulnerable to infection, the bacteria they carry become hardier — developing thick protective coatings and resistance to antibiotics — and more vigorous, multiplying and metabolizing faster.”
In their quest to combat bacterial infections aboard the ISS and for future missions, scientists are now looking to fight fire with fire, by engineering genetically modified microbes that can target and destroy select pathogens, remove toxins, modulate the immune system, and invade tumor tissue. Funded by the Translational Research Institute for Space Health (TRISH), a team at the Massachusetts Institute of Technology led by National Medal of Science recipient Prof. Robert Langer and his collaborator Prof. Giovanni Traverso is exploring ways to improve microbial therapies that reveal opportunities for caring for astronaut health in space, as detailed in their recent study published in the Journal of Experimental Medicine. Using synthetic biology tools and advanced microbiome research, researchers are now able to perform intracellular delivery of genetic payloads that displace infectious strains, thus addressing bacterial infections with much greater precision than through traditional treatments.
Microbial therapies remain experimental, but with more than 40 clinical trials underway, the technology for drug delivery to patients via genetically engineered microorganisms is nearing FDA approval.
TRISH’s LaunchPad: In line with its mission of enabling disruptive science and technologies to solve the challenges of human deep space exploration, the Translational Research Institute for Space Health (TRISH) is accepting applications for the TRISH LaunchPad – a program created in collaboration with CIMIT® CRAASH. The LaunchPad is an intensive 10-week program providing early-stage companies with access to space health and NASA experts and support to accelerate their technology towards use in space. Apply here by June 30th, 2019!
CIMIT® CRAASH: If you can’t make the TRISH LaunchPad deadline, check out the Commercialization Readiness Assessment and Accelerator for Solutions in Healthcare (CRAASH) program. This 10-session program (over 12 weeks) is aimed at accelerating the commercialization of healthcare innovations emerging from start-ups and academic labs. The program is delivered by industry veterans and is based on CIMIT‘s pioneering work facilitating innovations, the Coulter Foundation C3i Program and the NSF I-Corps Program, as well as university based curricula from MIT, Yale, and others.
Featured Image - Expedition 33 Commander Sunita Williams exercises on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station while participating in the first triathlon in space simultaneously with athletes in the Nautica Malibu Triathlon held in Southern California (16 Sept. 2012). Courtesy of NASA.