Should Science Give Astronauts Genetic Superpowers for Space Travel?
An astronaut peers through a portal in outer space.
What if people could just survive on sunlight like plants?
The admittedly outlandish question occurred to me after reading about how climate change will exacerbate drought, flooding, and worldwide food shortages. Many of these problems could be eliminated if human photosynthesis were possible. Had anyone ever tried it?
Extreme space travel exists at an ethically unique spot that makes human experimentation much more palatable.
I emailed Sidney Pierce, professor emeritus in the Department of Integrative Biology at the University of South Florida, who studies a type of sea slug, Elysia chlorotica, that eats photosynthetic algae, incorporating the algae's key cell structure into itself. It's still a mystery how exactly a slug can operate the part of the cell that converts sunlight into energy, which requires proteins made by genes to function, but the upshot is that the slugs can (and do) live on sunlight in-between feedings.
Pierce says he gets questions about human photosynthesis a couple of times a year, but it almost certainly wouldn't be worth it to try to develop the process in a human. "A high-metabolic rate, large animal like a human could probably not survive on photosynthesis," he wrote to me in an email. "The main reason is a lack of surface area. They would either have to grow leaves or pull a trailer covered with them."
In short: Plants have already exploited the best tricks for subsisting on photosynthesis, and unless we want to look and act like plants, we won't have much success ourselves. Not that it stopped Pierce from trying to develop human photosynthesis technology anyway: "I even tried to sell it to the Navy back in the day," he told me. "Imagine photosynthetic SEALS."
It turns out, however, that while no one is actively trying to create photosynthetic humans, scientists are considering the ways humans might need to change to adapt to future environments, either here on the rapidly changing Earth or on another planet. Rice University biologist Scott Solomon has written an entire book, Future Humans, in which he explores the environmental pressures that are likely to influence human evolution from this point forward. On Earth, Solomon says, infectious disease will remain a major driver of change. As for Mars, the big two are lower gravity and radiation, the latter of which bombards the Martian surface constantly because the planet has no magnetosphere.
Although he considers this example "pretty out there," Solomon says one possible solution to Mars' magnetic assault could leave humans not photosynthetic green, but orange, thanks to pigments called carotenoids that are responsible for the bright hues of pumpkins and carrots.
"Carotenoids protect against radiation," he says. "Usually only plants and microbes can produce carotenoids, but there's at least one kind of insect, a particular type of aphid, that somehow acquired the gene for making carotenoids from a fungus. We don't exactly know how that happened, but now they're orange... I view that as an example of, hey, maybe humans on Mars will evolve new kinds of pigmentation that will protect us from the radiation there."
We could wait for an orange human-producing genetic variation to occur naturally, or with new gene editing techniques such as CRISPR-Cas9, we could just directly give astronauts genetic advantages such as carotenoid-producing skin. This may not be as far-off as it sounds: Extreme space travel exists at an ethically unique spot that makes human experimentation much more palatable. If an astronaut already plans to subject herself to the enormous experiment of traveling to, and maybe living out her days on, a dangerous and faraway planet, do we have any obligation to provide all the protection we can?
Probably the most vocal person trying to figure out what genetic protections might help astronauts is Cornell geneticist Chris Mason. His lab has outlined a 10-phase, 500-year plan for human survival, starting with the comparatively modest goal of establishing which human genes are not amenable to change and should be marked with a "Do not disturb" sign.
To be clear, Mason is not actually modifying human beings. Instead, his lab has studied genes in radiation-resistant bacteria, such as the Deinococcus genus. They've expressed proteins called DSUP from tardigrades, tiny water bears that can survive in space, in human cells. They've looked into p53, a gene that is overexpressed in elephants and seems to protect them from cancer. They also developed a protocol to work on the NASA twin study comparing astronauts Scott Kelly, who spent a year aboard the International Space Station, and his brother Mark, who did not, to find out what effects space tends to have on genes in the first place.
In a talk he gave in December, Mason reported that 8.7 percent of Scott Kelly's genes—mostly those associated with immune function, DNA repair, and bone formation—did not return to normal after the astronaut had been home for six months. "Some of these space genes, we could engineer them, activate them, have them be hyperactive when you go to space," he said in that same talk. "When we think about having the hubris to go to a faraway planet...it seems like an almost impossible idea….but I really like people and I want us to survive for a long time, and this is the first step on the stairwell to survive out of the solar system."
What is the most important ability we could give our future selves through science?
There are others performing studies to figure out what capabilities we might bestow on the future-proof superhuman, but none of them are quite as extreme as photosynthesis (although all of them are useful). At Harvard, geneticist George Church wants to engineer cells to be resistant to viruses, such as the common cold and HIV. At Columbia, synthetic biologist Harris Wang is addressing self-sufficient humans more directly—trying to spur kidney cells to produce amino acids that are normally only available from diet.
But perhaps Future Humans author Scott Solomon has the most radical idea. I asked him a version of the classic What would be your superhero power? question: What does he see as the most important ability we could give our future selves through science?
"The empathy gene," he said. "The ability to put yourself in someone else's shoes and see the world as they see it. I think it would solve a lot of our problems."
Urinary tract infections account for more than 8 million trips to the doctor each year.
Few things are more painful than a urinary tract infection (UTI). Common in men and women, these infections account for more than 8 million trips to the doctor each year and can cause an array of uncomfortable symptoms, from a burning feeling during urination to fever, vomiting, and chills. For an unlucky few, UTIs can be chronic—meaning that, despite treatment, they just keep coming back.
But new research, presented at the European Association of Urology (EAU) Congress in Paris this week, brings some hope to people who suffer from UTIs.
Clinicians from the Royal Berkshire Hospital presented the results of a long-term, nine-year clinical trial where 89 men and women who suffered from recurrent UTIs were given an oral vaccine called MV140, designed to prevent the infections. Every day for three months, the participants were given two sprays of the vaccine (flavored to taste like pineapple) and then followed over the course of nine years. Clinicians analyzed medical records and asked the study participants about symptoms to check whether any experienced UTIs or had any adverse reactions from taking the vaccine.
The results showed that across nine years, 48 of the participants (about 54%) remained completely infection-free. On average, the study participants remained infection free for 54.7 months—four and a half years.
“While we need to be pragmatic, this vaccine is a potential breakthrough in preventing UTIs and could offer a safe and effective alternative to conventional treatments,” said Gernot Bonita, Professor of Urology at the Alta Bro Medical Centre for Urology in Switzerland, who is also the EAU Chairman of Guidelines on Urological Infections.
The news comes as a relief not only for people who suffer chronic UTIs, but also to doctors who have seen an uptick in antibiotic-resistant UTIs in the past several years. Because UTIs usually require antibiotics, patients run the risk of developing a resistance to the antibiotics, making infections more difficult to treat. A preventative vaccine could mean less infections, less antibiotics, and less drug resistance overall.
“Many of our participants told us that having the vaccine restored their quality of life,” said Dr. Bob Yang, Consultant Urologist at the Royal Berkshire NHS Foundation Trust, who helped lead the research. “While we’re yet to look at the effect of this vaccine in different patient groups, this follow-up data suggests it could be a game-changer for UTI prevention if it’s offered widely, reducing the need for antibiotic treatments.”
MILESTONE: Doctors have transplanted a pig organ into a human for the first time in history
A surgeon at Massachusetts General Hospital prepares a pig organ for transplant.
Surgeons at Massachusetts General Hospital made history last week when they successfully transplanted a pig kidney into a human patient for the first time ever.
The recipient was a 62-year-old man named Richard Slayman who had been living with end-stage kidney disease caused by diabetes. While Slayman had received a kidney transplant in 2018 from a human donor, his diabetes ultimately caused the kidney to fail less than five years after the transplant. Slayman had undergone dialysis ever since—a procedure that uses an artificial kidney to remove waste products from a person’s blood when the kidneys are unable to—but the dialysis frequently caused blood clots and other complications that landed him in the hospital multiple times.
As a last resort, Slayman’s kidney specialist suggested a transplant using a pig kidney provided by eGenesis, a pharmaceutical company based in Cambridge, Mass. The highly experimental surgery was made possible with the Food and Drug Administration’s “compassionate use” initiative, which allows patients with life-threatening medical conditions access to experimental treatments.
The new frontier of organ donation
Like Slayman, more than 100,000 people are currently on the national organ transplant waiting list, and roughly 17 people die every day waiting for an available organ. To make up for the shortage of human organs, scientists have been experimenting for the past several decades with using organs from animals such as pigs—a new field of medicine known as xenotransplantation. But putting an animal organ into a human body is much more complicated than it might appear, experts say.
“The human immune system reacts incredibly violently to a pig organ, much more so than a human organ,” said Dr. Joren Madsen, director of the Mass General Transplant Center. Even with immunosuppressant drugs that suppress the body’s ability to reject the transplant organ, Madsen said, a human body would reject an animal organ “within minutes.”
So scientists have had to use gene-editing technology to change the animal organs so that they would work inside a human body. The pig kidney in Slayman’s surgery, for instance, had been genetically altered using CRISPR-Cas9 technology to remove harmful pig genes and add human ones. The kidney was also edited to remove pig viruses that could potentially infect a human after transplant.
With CRISPR technology, scientists have been able to prove that interspecies organ transplants are not only possible, but may be able to successfully work long term, too. In the past several years, scientists were able to transplant a pig kidney into a monkey and have the monkey survive for more than two years. More recently, doctors have transplanted pig hearts into human beings—though each recipient of a pig heart only managed to live a couple of months after the transplant. In one of the patients, researchers noted evidence of a pig virus in the man’s heart that had not been identified before the surgery and could be a possible explanation for his heart failure.
So far, so good
Slayman and his medical team ultimately decided to pursue the surgery—and the risk paid off. When the pig organ started producing urine at the end of the four-hour surgery, the entire operating room erupted in applause.
Slayman is currently receiving an infusion of immunosuppressant drugs to prevent the kidney from being rejected, while his doctors monitor the kidney’s function with frequent ultrasounds. Slayman is reported to be “recovering well” at Massachusetts General Hospital and is expected to be discharged within the next several days.