Indiana bone loss scientist's research sends mice into space

INDIANAPOLIS (AP) - When SpaceX launched its Dragon resupply capsule to the International Space Station last month, it had the usual: food, spacewalk equipment, and spare parts. But it was also carrying something out of the ordinary: a research experiment from IUPUI that could lead to a better bone-healing drug.

Melissa Kacena, Ph.D., is a professor of orthopedic surgery at IU School of Medicine. Together with the U.S. Department of Defense and NASA, she has developed a new drug technology - patented in April - to speed bone damage recovery.

NASA hopes Kacena's drug could help astronauts, who lose bone mass in space. The U.S. Army also is counting on it to help heal soldiers with blast wounds. And for the general public, the new drug could help treat car accident victims or those with osteoporosis.

But before the new drug makes its way to humans, Kacena is testing how well it works on mice that she has sent into space.

"These experiments will be critical in saying this (drug) is worth going to the next step," she said.

Out with the old, in with the new

Last week's SpaceX launch is not the first time one of Kacena's experiments has been out of this world. In 2017, she sent dozens of mice to the space station to test the effects of spaceflight on bone fracture healing. This time, Kacena will test the effects of the new drug on the mice's bone regrowth cells - osteoblasts - themselves.

Normal bone regrowth relies on signals from both osteoblasts and osteoclasts, which break down bone. With gravity, the osteoclasts and osteoblasts work in harmony. On average, an individual "grows" a new skeleton every seven years.

In space, however, the body doesn't need support against gravity. Osteoclasts continue removing bone but don't signal new bone growth to replace it. As a result, astronauts lose 1 to 3% of their bone density every month, compared to a typical person with osteoporosis who experiences a 1% loss per year.

That is why Kacena is testing her drug in zero-gravity, where she hopes it will be able to stimulate growth without that signal.

"If it can heal in space, it can heal anywhere," said Kacena.

A medication to help speed the bone regrowth process does already exist. That said, the FDA-approved medication also requires bearing weight on the affected bone.

"(The FDA-approved drug) requires gravity to help the way it works," Kacena said. "If the patient has been bedridden, or in a wheelchair, or if the patient is on crutches, you're not getting that extra stimulation that's required."

Without weight-bearing stimulation to the damaged bone, the patient may suffer considerable bone density loss. She hopes that her space experiment will show that the new drug does not require gravity to enhance bone regrowth.

Kacena also aims to have a drug that won't increase cancer risk, which is a side effect of the current FDA-approved drug.

"What we're trying to understand is, what are the advantages of this (new drug) compared to what's currently used?" she said.

While Kacena is now a professor of orthopedic surgery, her degrees are in aerospace engineering. As an undergraduate and a master's student in Colorado, she studied how bacteria grow in different environments, including space.

But it wasn't until halfway through her Ph.D. that she was introduced to research about bone loss in space. She was hooked.

Even with a year of research experience and a job offer from Yale, Kacena was drawn to IUPUI's large bone research group and opportunities for collaboration.

An unlikely partnership between Kacena's laboratory, NASA, and the U.S. Department of Defense formed in 2013 when she met U.S. Army researcher Rasha Hammamieh. They discovered a shared research passion for bone loss, bone healing, and spaceflight.

"Sometimes the science takes you where the science takes you," she said. "And you just have to follow it."

Most recently, Kacena's science took her and her researchers to the Kennedy Space Center for the SpaceX launch. They arrived two weeks before the launch to prepare the bone cells for launch. Astronauts will spend two weeks running Kacena's experiment that compares bone cell growth using the current drug, the new drug, and no drugs, both on Earth and in space.

The group expects to confirm that spaceflight represses bone cell growth. And based on research completed on Earth, they expect that each drug will change some aspects of the cells in different ways.

Ideally, the new drug will stimulate bone growth even in space.

A pathway to clinical trials for Kacena's new drug opened once it was patented in April. But gaining FDA approval can take years or decades.

"We know that our drug works really well for healing in mice, rats and pigs," Kacena said. "It may not be in the clinic for a while, but it would be possible in my lifetime."

In the immediate future, Kacena and her team will continue analyzing the data from their 2017 experiment. In a few weeks, they'll be able to analyze data from the 2019 experiment, as well.

"My ultimate goal is to help the patient," she said, "whether it's the injured soldier, or whether it's somebody in a car crash...or for somebody with osteoporosis to improve their bone mass."

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Follow the experiment's progress at the laboratory's blog site: https://medicine.iu.edu/blogs/bone-healing-in-space/

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Source: The Indianapolis Star

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Information from: The Indianapolis Star, http://www.indystar.com