Worms slither their way through dirt, over land, and in water. In fact, the tiny creatures can be found in nearly every habitat on Earth, even volcanic vents on the sea floor. Now they may have conquered space, too.
In February, NASA sent tens of thousands of worms to space. Their destination was the International Space Station (ISS). While they cozy up to the astronauts already living there, the worms will flex their muscles as they navigate a minuscule obstacle course. This may seem like a frivolous experiment, but it has a critical purpose: to study how space causes the loss of muscle mass in astronauts.
What's new — On February 20, NASA sent a Northrop Grumman Cygnus resupply spacecraft to the ISS packed with 8,000 pounds of precious science cargo, and other supplies for astronauts.
In the cargo was a special package, containing some 120,000 Caenorhabditis elegans worms. There was also a device designed to measure their muscle strength in a microgravity environment. C. elegans are a type of nematode, also known as roundworms. They are not in the same phylum as annelids, or segmented worms, like the earthworm. Rather, they are the ultra animal model — one of the most studied creatures on the planet, and considered an analog species for more complex organisms, including humans.
Nathaniel Szewczyk is a researcher at Ohio University and one of the co-investigators behind the new experiment. He says if researchers can get a handle on what happens to these model organisms in space, then it could crack open exactly what is happening to astronauts' bodies, too.
"If the molecules are effectively the same between worms and rodents and people, and the effects are basically the same, then things should translate fairly quickly," Szewczyk tells Inverse.
Why it matters — Over the past 60 years, humans have been a near-constant presence in space. With the Apollo missions, astronauts made their way to the Moon. And for the past 20 years, a rotating, international crew of astronauts have made a temporary home on the ISS, an orbiting complex flying 254 miles above Earth's surface. Both private space firms and government-sponsored space agencies have crewed missions planned over the next decade to send more and more humans into space than ever before.
A total of 240 people have been on the ISS, some staying in space just for a few weeks or months, or, in the case of astronauts Peggy Whitson and Mark Kelly, almost as long as a year at a time. As more humans go into space and come back to Earth, their stays have changed how scientists understand the effects of spaceflight on the human body.
One of the more troubling effects is an apparent loss of muscle mass in astronauts who live in a microgravity environment. But what causes the loss is a mystery — and so is how to treat, and prevent it from happening in the first place.
Digging into the details — Astronauts onboard the ISS don't need to use their bones and muscles to support the full mass of their bodies in the same way they do on Earth. Despite following a strict routine of regular exercise and nutrient-laden diet in space, astronauts in a microgravity environment typically lose some of their bone and muscle mass.
In the past few years, several studies have tried to resolve what, exactly, is happening to astronauts' bones and muscles. This is particularly imperative as humans start venturing out onto longer duration space travel to further-away destinations like Mars.
But when you think of muscle loss in humans, you don't exactly correlate it with small and slimy creatures that inch their way forward and backward through life.
"Worms are teeny tiny little creatures and it's just absolutely shocking that they even have muscles," Szewczyk says.
"But that's the thing. When you stop and think about it, you realize that worms and people both need muscles to move from point A to point B and quite surprisingly, a lot of little bits inside the muscle cells are effectively the same," he explains.
A case in point is myosin — a protein which is also one of the focal points of the experiment.
What's next — Myosin is one of the major proteins involved in muscle contraction, and it is present in both people and worms. In turn, worms are an ideal subject for this type of experiment.
To test muscle loss in worms in space, the researchers behind the experiment designed a small device called NemaFlex. NemaFlex looks like an old cassette recorder, but it is actually a very small obstacle course built especially for the worms.
Onboard the ISS, the worms will be placed inside the device and forced to wiggle their way through tiny, bendable pillars. As they move through the obstacle course, a microscopic camera will measure how much each pillar bends, which in turn reveals the degree of force the worm exerts on the pillar with their muscles.
"The physics is exactly the same for measuring human strength as it is for worm strength — it's just that you need a teeny, tiny little force plate to push against," Szewczyk says.
Following the initial testing, there will be further follow-up experiments after the worms have been in space for two to four weeks to measure any changes in their muscle mass after spending time in space.
After they are done flexing, the worms will journey back to Earth. Once on the ground, additional testing will reveal any changes in the worms' gene expression and muscle strength. Together, these experiments will give scientists a better understanding of how muscles adapt to the microgravity environment.
Although some may be skeptical of how much studying worms can tell us about humans, Szewczyk says, on a molecular level, there is a strong correlation between the two creatures.
"But it's also equally entirely true that there's lots of people who think that that's crazy talk," Szewczyk says.