NASA astronaut Frank Rubio floats by the International Space Station’s “window to the world.” Yesterday, he returned from the longest single spaceflight by a U.S. astronaut on record - over one year. Exploring deep space will require even longer missions.
Yesterday, NASA astronaut Frank Rubio returned to Earth after over one year, the longest single spaceflight for a U.S. astronaut. But this is just the start; longer and more complex missions into deep space loom ahead, from returning to the moon in 2025 to eventually sending humans to Mars. To ensure that these missions succeed, NASA is increasing efforts to study the biological effects and prevent harm.
The dangers of microgravity are real
A NASA report published in 2016 details a long list of incidents and near-misses caused – at least partly – by space-induced changes in astronauts’ vision and coordination. These issues make it harder to move with precision and to judge distance and velocity.
According to the report, in 1997, a resupply ship collided with the Mir space station, possibly because a crew member bumped into the commander during the final docking maneuver. This mishap caused significant damage to the space station.
Returns to Earth suffered from problems, too. The same report notes that touchdown speeds during the first 100 space shuttle landings were “outside acceptable limits. The fastest landing on record – 224 knots (258 miles) per hour – was linked to the commander’s momentary spatial disorientation.” Earlier, each of the six Apollo crews that landed on the moon had difficulty recognizing moon landmarks and estimating distances. For example, Apollo 15 landed in an unplanned area, ultimately straddling the rim of a five-foot deep crater on the moon, harming one of its engines.
Spaceflight causes unique stresses on astronauts’ brains and central nervous systems. NASA is working to reduce these harmful effects.
NASA
Space messes up your brain
In space, astronauts face the challenges of microgravity, ionizing radiation, social isolation, high workloads, altered circadian rhythms, monotony, confined living quarters and a high-risk environment. Among these issues, microgravity is one of the most consequential in terms of physiological changes. It changes the brain’s structure and its functioning, which can hurt astronauts’ performance.
The brain shifts upwards within the skull, displacing the cerebrospinal fluid, which reduces the brain’s cushioning. Essentially, the brain becomes crowded inside the skull like a pair of too-tight shoes.
That’s partly because of how being in space alters blood flow. On Earth, gravity pulls our blood and other internal fluids toward our feet, but our circulatory valves ensure that the fluids are evenly distributed throughout the body. In space, there’s not enough gravity to pull the fluids down, and they shift up, says Rachael D. Seidler, a physiologist specializing in spaceflight at the University of Florida and principal investigator on many space-related studies. The head swells and legs appear thinner, causing what astronauts call “puffy face chicken legs.”
“The brain changes at the structural and functional level,” says Steven Jillings, equilibrium and aerospace researcher at the University of Antwerp in Belgium. “The brain shifts upwards within the skull,” displacing the cerebrospinal fluid, which reduces the brain’s cushioning. Essentially, the brain becomes crowded inside the skull like a pair of too-tight shoes. Some of the displaced cerebrospinal fluid goes into cavities within the brain, called ventricles, enlarging them. “The remaining fluids pool near the chest and heart,” explains Jillings. After 12 consecutive months in space, one astronaut had a ventricle that was 25 percent larger than before the mission.
Some changes reverse themselves while others persist for a while. An example of a longer-lasting problem is spaceflight-induced neuro-ocular syndrome, which results in near-sightedness and pressure inside the skull. A study of approximately 300 astronauts shows near-sightedness affects about 60 percent of astronauts after long missions on the International Space Station (ISS) and more than 25 percent after spaceflights of only a few weeks.
Another long-term change could be the decreased ability of cerebrospinal fluid to clear waste products from the brain, Seidler says. That’s because compressing the brain also compresses its waste-removing glymphatic pathways, resulting in inflammation, vulnerability to injuries and worsening its overall health.
The effects of long space missions were best demonstrated on astronaut twins Scott and Mark Kelly. This NASA Twins Study showed multiple, perhaps permanent, changes in Scott after his 340-day mission aboard the ISS, compared to Mark, who remained on Earth. The differences included declines in Scott’s speed, accuracy and cognitive abilities that persisted longer than six months after returning to Earth in March 2016.
By the end of 2020, Scott’s cognitive abilities improved, but structural and physiological changes to his eyes still remained, he said in a BBC interview.
“It seems clear that the upward shift of the brain and compression of the surrounding tissues with ventricular expansion might not be a good thing,” Seidler says. “But, at this point, the long-term consequences to brain health and human performance are not really known.”
NASA astronaut Kate Rubins conducts a session for the Neuromapping investigation.
NASA
Staying sharp in space
To investigate how prolonged space travel affects the brain, NASA launched a new initiative called the Complement of Integrated Protocols for Human Exploration Research (CIPHER). “CIPHER investigates how long-duration spaceflight affects both brain structure and function,” says neurobehavioral scientist Mathias Basner at the University of Pennsylvania, a principal investigator for several NASA studies. “Through it, we can find out how the brain adapts to the spaceflight environment and how certain brain regions (behave) differently after – relative to before – the mission.”
To do this, he says, “Astronauts will perform NASA’s cognition test battery before, during and after six- to 12-month missions, and will also perform the same test battery in an MRI scanner before and after the mission. We have to make sure we better understand the functional consequences of spaceflight on the human brain before we can send humans safely to the moon and, especially, to Mars.”
As we go deeper into space, astronauts cognitive and physical functions will be even more important. “A trip to Mars will take about one year…and will introduce long communication delays,” Seidler says. “If you are on that mission and have a problem, it may take eight to 10 minutes for your message to reach mission control, and another eight to 10 minutes for the response to get back to you.” In an emergency situation, that may be too late for the response to matter.
“On a mission to Mars, astronauts will be exposed to stressors for unprecedented amounts of time,” Basner says. To counter them, NASA is considering the continuous use of artificial gravity during the journey, and Seidler is studying whether artificial gravity can reduce the harmful effects of microgravity. Some scientists are looking at precision brain stimulation as a way to improve memory and reduce anxiety due to prolonged exposure to radiation in space.
Other scientists are exploring how to protect neural stem cells (which create brain cells) from radiation damage, developing drugs to repair damaged brain cells and protect cells from radiation.
To boldly go where no astronauts have gone before, they must have optimal reflexes, vision and decision-making. In the era of deep space exploration, the brain—without a doubt—is the final frontier.
Additionally, NASA is scrutinizing each aspect of the mission, including astronaut exercise, nutrition and intellectual engagement. “We need to give astronauts meaningful work. We need to stimulate their sensory, cognitive and other systems appropriately,” Basner says, especially given their extreme confinement and isolation. The scientific experiments performed on the ISS – like studying how microgravity affects the ability of tissue to regenerate is a good example.
“We need to keep them engaged socially, too,” he continues. The ISS crew, for example, regularly broadcasts from space and answers prerecorded questions from students on Earth, and can engage with social media in real time. And, despite tight quarters, NASA is ensuring the crew capsule and living quarters on the moon or Mars include private space, which is critical for good mental health.
Exploring deep space builds on a foundation that began when astronauts first left the planet. With each mission, scientists learn more about spaceflight effects on astronauts’ bodies. NASA will be using these lessons to succeed with its plans to build science stations on the moon and, eventually, Mars.
“Through internally and externally led research, investigations implemented in space and in spaceflight simulations on Earth, we are striving to reduce the likelihood and potential impacts of neurostructural changes in future, extended spaceflight,” summarizes NASA scientist Alexandra Whitmire. To boldly go where no astronauts have gone before, they must have optimal reflexes, vision and decision-making. In the era of deep space exploration, the brain—without a doubt—is the final frontier.
Many women want non-hormonal birth control. A 22-year-old's findings were used to launch a company that could, within the decade, bring a new kind of contraceptive to the marketplace.
Now a scientist with NextVivo, Shrestha is not directly involved in the development of the contraceptive that is based on her research. But, back in 2016 when she was going through her own problems with hormonal contraceptives, she “was very personally invested” in her research project, Shrestha says. She was coping with a long list of negative effects from an implanted hormonal IUD. According to the Mayo Clinic, those can include severe pelvic pain, headaches, acute acne, breast tenderness, irregular bleeding and mood swings. After a year, she had the IUD removed, but it took another full year before all the side effects finally subsided; she also watched her sister suffer the “same tribulations” after trying a hormonal IUD, she says.
For contraceptive use either daily or monthly, Shrestha says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
Shrestha unshelved antibody research that had been sitting idle for decades. It was in the late 80s that scientists in Japan first tried to develop anti-sperm antibodies for contraceptive use. But, 35 years ago, “Antibody production had not been streamlined as it is now, so antibodies were very expensive,” Shrestha explains. So, they shifted away from birth control, opting to focus on developing antibodies for vaccines.
Over the course of the last three decades, different teams of researchers have been working to make the antibody more effective, bringing the cost down, though it’s still expensive, according to Shrestha. For contraceptive use either daily or monthly, she says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
The problem
The problem with contraceptives for women, Shrestha says, is that all but a few of them are hormone-based or have other negative side effects. In fact, some studies and reports show that millions of women risk unintended pregnancy because of medical contraindications with hormone-based contraceptives or to avoid the risks and side effects. While there are about a dozen contraceptive choices for women, there are two for men: the condom, considered 98% effective if used correctly, and vasectomy, 99% effective. Neither of these choices are hormone-based.
On the non-hormonal side for women, there is the diaphragm which is considered only 87 percent effective. It works better with the addition of spermicides — Nonoxynol-9, or N-9 — however, they are detergents; they not only kill the sperm, they also erode the vaginal epithelium. And, there’s the non-hormonal IUD which is 99% effective. However, the IUD needs to be inserted by a medical professional, and it has a number of negative side effects, including painful cramping at a higher frequency and extremely heavy or “abnormal” and unpredictable menstrual flows.
The hormonal version of the IUD, also considered 99% effective, is the one Shrestha used which caused her two years of pain. Of course, there’s the pill, which needs to be taken daily, and the birth control ring which is worn 24/7. Both cause side effects similar to the other hormonal contraceptives on the market. The ring is considered 93% effective mostly because of user error; the pill is considered 99% effective if taken correctly.
“That’s where we saw this opening or gap for women. We want a safe, non-hormonal contraceptive,” Shrestha says. Compounding the lack of good choices, is poor access to quality sex education and family planning information, according to the non-profit Urban Institute. A focus group survey suggested that the sex education women received “often lacked substance, leaving them feeling unprepared to make smart decisions about their sexual health and safety,” wrote the authors of the Urban Institute report. In fact, nearly half (45%, or 2.8 million) of the pregnancies that occur each year in the US are unintended, reports the Guttmacher Institute. Globally the numbers are similar. According to a new report by the United Nations, each year there are 121 million unintended pregnancies, worldwide.
The science
The early work on antibodies as a contraceptive had been inspired by women with infertility. It turns out that 9 to 12 percent of women who are treated for infertility have antibodies that develop naturally and work against sperm. Shrestha was encouraged that the antibodies were specific to the target — sperm — and therefore “very safe to use in women.” She aimed to make the antibodies more stable, more effective and less expensive so they could be more easily manufactured.
Since antibodies tend to stick to things that you tell them to stick to, the idea was, basically, to engineer antibodies to stick to sperm so they would stop swimming. Shrestha and her colleagues took the binding arm of an antibody that they’d isolated from an infertile woman. Then, targeting a unique surface antigen present on human sperm, they engineered a panel of antibodies with as many as six to 10 binding arms — “almost like tongs with prongs on the tongs, that bind the sperm,” explains Shrestha. “We decided to add those grabbers on top of it, behind it. So it went from having two prongs to almost 10. And the whole goal was to have so many arms binding the sperm that it clumps it” into a “dollop,” explains Shrestha, who earned a patent on her research.
Suruchi Shrestha works in the lab with a colleague. In 2016, her research on antibodies for birth control was inspired by her own experience with side effects from an implanted hormonal IUD.
UNC - Chapel Hill
The sperm stays right where it met the antibody, never reaching the egg for fertilization. Eventually, and naturally, “Our vaginal system will just flush it out,” Shrestha explains.
“She showed in her early studies that [she] definitely got the sperm immotile, so they didn't move. And that was a really promising start,” says Jasmine Edelstein, a scientist with an expertise in antibody engineering who was not involved in this research. Shrestha’s team at UNC reproduced the effect in the sheep, notes Edelstein, who works at the startup Be Biopharma. In fact, Shrestha’s anti-sperm antibodies that caused the sperm to agglutinate, or clump together, were 99.9% effective when delivered topically to the sheep’s reproductive tracts.
The future
Going forward, Shrestha thinks the ideal approach would be delivering the antibodies through a vaginal ring. “We want to use it at the source of the spark,” Shrestha says, as opposed to less direct methods, such as taking a pill. The ring would dissolve after one month, she explains, “and then you get another one.”
Engineered to have a long shelf life, the anti-sperm antibody ring could be purchased without a prescription, and women could insert it themselves, without a doctor. “That's our hope, so that it is accessible,” Shrestha says. “Anybody can just go and grab it and not worry about pregnancy or unintended pregnancy.”
Her patented research has been licensed by several biotech companies for clinical trials. A number of Shrestha’s co-authors, including her lab advisor, Sam Lai, have launched a company, Mucommune, to continue developing the contraceptives based on these antibodies.
And, results from a small clinical trial run by researchers at Boston University Chobanian & Avedisian School of Medicine show that a dissolvable vaginal film with antibodies was safe when tested on healthy women of reproductive age. That same group of researchers last year received a $7.2 million grant from the National Institute of Health for further research on monoclonal antibody-based contraceptives, which have also been shown to block transmission of viruses, like HIV.
“As the costs come down, this becomes a more realistic option potentially for women,” says Edelstein. “The impact could be tremendous.”
This article was first published by Leaps.org in December, 2022. It has been lightly edited with updates for timeliness.