Research in space yields clues to treating muscle loss back on Earth

Quick look

Iowa State researcher Khaled Kamal is mapping how microgravity conditions during spaceflight accelerate human muscle loss, work that could influence NASA’s long‑duration missions and help develop emerging therapies for muscular dystrophy, age-related sarcopenia, immobilization due to injury or long hospital stays, and health impacts related to sedentary lifestyles here on Earth.

AMES, Iowa – Nearly 15 years ago, Khaled Kamal was deep into his graduate work in genetics and cellular biology when an unexpected opportunity sent his career into orbit.

He learned he’d been selected to work on an upcoming NASA-European Space Agency mission.

“I think my first reaction was that there must have been some kind of mistake,” Kamal said with a smile. “It was a very exciting opportunity and something I wasn’t expecting because as a young biologist, I thought space research was reserved for engineers.”

That assignment – analyzing plant samples sent to the International Space Station – set Kamal on a path that would bring him to Iowa State University, where he now serves as assistant professor of kinesiology and health and leads the university’s Musculoskeletal Redox & Therapeutics Laboratory, a research program exploring how spaceflight reshapes the human body and how those discoveries can help people on Earth.

His research questions cut to the core of human physiology.

Why do astronauts lose muscle so fast?

Why does microgravity accelerate aging-like decline in the body?

And can the same pathways that erode strength in orbit help explain – and maybe treat – muscular dystrophy, age‑related muscle loss and long‑term disuse?

“As NASA prepares for longer missions to the Moon and Mars, answering these questions has become increasingly important, yet the implications extend far beyond space exploration,” Kamal said. “If we can understand how the body breaks down in extreme environments, we can help people facing muscle loss here at home.”

The forces our muscles depend on

Space is a perfect storm of biological stressors: mechanical unloading, radiation, isolation and disrupted circadian rhythms. On Earth, gravity provides a constant mechanical signal that muscles and bones rely on. In orbit, that signal disappears – and cells panic.

“The body doesn’t know what gravity is,” Kamal said. “It only knows what happens when it’s gone.”

And while a tiny amount of gravity still exists everywhere in space (“including enough to keep the moon orbiting Earth and Earth orbiting the sun,” Kamal said), microgravity conditions make astronauts – and everything around them – appear weightless.

“Astronauts float because a spacecraft in orbit is in constant free‑fall around Earth,” Kamal explained. “Everything – the station, the crew, their tools – is falling together at the same speed, creating the sensation of weightlessness.”

And that sensation of weightlessness has consequences. Without the mechanical cues gravity provides, the body’s mechanotransduction systems – the molecular machinery that senses force – begin to fail.

“It’s like the body is asking, ‘Where’s the enemy?'” Kamal said. “Many of the same stress and inflammatory pathways that respond to injury or disease become activated.”

The result is rapid deterioration. Human postural muscles, which help keep the body upright, can lose as much as 10-20% of their mass during the first months in space, and bone density declines at rates far beyond normal aging.

“On Earth, people lose about 1% of bone density per year after age 50,” Kamal said. “In space, astronauts lose 1.2% of bone density per month.”

This means that even elite astronauts – “super healthy, athletic people,” Kamal said – return from space weakened to the point that they’re unable to hold simple objects – a book, for example – for weeks.

Same problem, different speed

Kamal said what makes his research especially impactful is that the same cellular and molecular failures that unfold in space also appear in people who never leave the ground, including children with Duchenne muscular dystrophy, adults with age‑related sarcopenia, patients immobilized by injury or long hospital stays, and even people living sedentary lifestyles.

“All of these conditions share a common theme: the mechanotransduction system is failing,” Kamal said. “Space just accelerates it.”

Kamal said spaceflight acts as a biological fast-forward button in many ways.

“What takes years or decades on Earth can be observed in just a few weeks in space,” Kamal said. “This gives us a rare chance to spot early warning signs and test interventions faster.”

Tracking the body’s early distress signals

On the Iowa State campus, Kamal and his research team use a mix of investigative approaches, laboratory models and astronaut-derived data to study how muscles respond in microgravity.

For example, Kamal is currently leading a NASA GeneLab Analysis Working Group to analyze small extracellular vesicles – fluid-filled transport sacs – taken from astronaut blood, whose shifting RNA cargo signals early immune, mitochondrial and oxidative stress.

“Each astronaut’s vesicles tell a molecular story, and they show us how the body is adapting – or struggling – in real time,” Kamal said. “These biomarkers could one day help clinicians track muscle decline in aging adults or patients with chronic disease.”

Another research project is focused on exercise‑mimetic exosomes, which are tiny vesicles released by mechanically loaded muscle cells. In healthy tissue, these exosomes carry anti‑inflammatory and metabolic signals; however, in dystrophic or unloaded muscle, they deliver stress signals that accelerate damage.

Kamal’s team discovered that “exerosomes,” which are exosomes generated from mechanically stretched muscle cells, can reprogram diseased vesicles and help restore healthier communication between muscle and bone.

“It’s like flipping the switch from a destructive message to a regenerative one,” Kamal said.

This discovery recently received national recognition when Kamal and his team earned first place in the 2026 American Physiology Summit (APS) Hot Topics in Muscle Biology Award Competition, as well as APS Abstract of Distinction honors.

As part of their on-going research, Kamal and his team are also probing Piezo1, a mechanosensitive ion channel that helps muscle cells detect force.

“In microgravity conditions, Piezo1 activity drops, and we’ve been able to show that activating Piezo1 pharmacologically can partially restore mechanotransduction during unloading,” Kamal said. “This has the potential to give us an early‑stage countermeasure for astronauts and patients with disuse atrophy.”

Together, Kamal said these projects share a common goal of “understanding how cells sense, communicate and adapt to mechanical forces, whether in space, during aging or in disease.”

The future we’re working for every day

Namitha Bannimath, a current Ph.D. student in kinesiology and health at Iowa State, has spent the past year as a member of Kamal’s research team and said the experience has helped reshape how she approaches science.

“This research has taught me so much about patience and confidence,” Bannimath said. “You need both – patience to figure out what isn’t working, and confidence to keep going and never give up. I want to help make a difference in people’s lives, and this work has the potential to do that. It’s incredibly rewarding.”

Kamal said training the next generation of scientists is as important as the discoveries themselves and remains a powerful motivator in his work.

“Through the Musculoskeletal Redox & Therapeutics Laboratory at Iowa State, students gain hands-on experience tackling questions that span space biology, aging, muscle disease and regenerative medicine,” he said.

“What happens in space may one day allow us to help millions of people stay stronger and live healthier lives on Earth. That’s the future we’re working toward every day.”