Bioreactor research could ensure healthy space travel

Bioreactors like this one simulate the biological effects of weightlessness

May 9, 2000
Web posted at: 4:08 p.m. EDT (2008 GMT)

By Richard Stenger
CNN Interactive Writer

ATLANTA (CNN) -- Wearing large glasses and a white lab coat with a NASA space shuttle patch, Gary Sanford peers in on one of his experiments. Inside a rotating glass dish, about the size of a hockey puck, a clump of cells churns end over end.

The blood vessel cells are "growing totally different than anything we've seen in normal cell culture," said Sanford, a biochemist at The Morehouse School of Medicine in Atlanta.

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Along with a team of researchers, Sanford is performing studies that could prove crucial in protecting the health of the next generation of astronauts using bioreactors, devices that simulate the biological effects of weightlessness.

Morehouse established its Space Medicine and Life Sciences Research Center in 1995 to research the effects of microgravity on the human body. Funded by NASA, the center focuses on how space travel can alter cardiovascular, muscle, brain and bone tissues.

In a bioreactor, the basic biological building blocks grow in unusual patterns because the device creates conditions whereby they behave as if they were suspended in weightlessness, according to the Morehouse researchers.

Biochemist Gary Sanford examines a bioreactor experiment at Morehouse University

On a human level, the lack of gravity can alter the biochemistry of astronauts and threaten their well being. For example, when people return from zero gravity to Earth, their blood pressure can drop precipitously because of physical changes in their blood vessels.

Astronauts also experience bone loss, muscle atrophy and other physiological alterations. By studying cells in the bioreactor, Morehouse medical researchers hope to generate data that will lead to medical strategies to counteract the effects of weightlessness.

"What we are doing here is providing the kind of data NASA managers need. They can't do all they research they need to do in space. There aren't enough shuttle flights going up. It's not like Delta," said Sandra A. Harris-Hooker, a vascular tissue specialist.

Bioreactors consist of small, customized thick glass containers. Inside, slow moving motors stir up a potion of cells and cell food. Slowly and steadily cascading in circles, the cells cannot determine which way is up and behave as they would in the weightlessness of space.

"When it is rotated slowly, cells do not form any solid surfaces. They remain fluid, floating in free fall," said Myrtle Thierry-Palmer, the center's director.

The embryonic mouse cells in the top image spent two fewer days in the bioreactor than those in the bottom image, and exhibit much less bone tissue formation

Morehouse researchers are using the bioreactor to investigate the properties of many types of tissue. For example, under normal conditions, embryonic bone cells become cartilage and then mineralize into calcium.

But in the device, young bone cells have trouble mineralizing into calcium. Others, a few days older, calcify more. Why the cells take different routes remains a mystery, but finding the answer could advance space medicine, said Morehouse researcher Brenda Klement.

The natural healing process from a fracture resembles the embryonic mineralization process, Klement said. And since astronauts lose bone density, the risk of fractures increases for them.

Another Morehouse scientist, Rajagopala Sridaran, is using the bioreactor to determine the effects of microgravity on ovulation. Studies indicate that levels of progesterone, a vital hormone in the pregnancy process, go down in space.

Yet pregnancies in space will become a real possibility with the long-term habitation of space, beginning with the International Space Station, the Morehouse researchers said. The research could lead to medical practices that ensure healthy fetuses, they said.

Much of the bioreactor work at Morehouse will benefit people on Earth as well as space, according to the researchers.

Kamla Dutt, for example, is studying eye-related neuron cells. They do not divide in culture, but genes were introduced to convince them to split into new cells in the bioreactor environment.

"We don't know why, but we're getting mature looking neuron cells," Dutt said. More studies are necessary to determine if they are functional, she added. If they are, they could be developed into transplant tissue to correct certain forms of blindness, she said.

Sanford's work on blood vessel cells and blood pressure has real world applications as well. The temporary hypertension that astronauts returning to Earth experience is "similar to when a patient gets up after being bed ridden a long time, he said.

Related findings on how new blood vessels form could shed light on how to stop cancerous growths. "It's a major issue. Not just from a NASA standpoint, but for the general public as well," he said.

Associate Editor Meriah Doty contributed to this report.

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