Air Filters May Be Key to Human Organ Regeneration

Industrial air filters may harbor key to human organ regeneration

The rat in Sally Meiners’ New Jersey lab stood on its hind legs, spied food and darted to the other end of the cage to grab the morsel. Just four days earlier, the rat had sat motionless, its spine severed and hind legs paralyzed.

The latest medical miracle? Perhaps.

In a bizarre twist, the rat appears to owe its quick recovery to the same material that Donaldson Co. Inc. of Bloomington, Ill., has been using for 25 years in the industrial air filters it makes for factories, trucks and airplanes.

Three years ago, Meiners’ husband, Michigan State University molecular biologist Melvin Schindler, discovered that the tiny fibers in Donaldson’s synthetic filters looked just like the natural collagen surface on which animal cells grow. And when Schindler placed a few human breast cells on the tiny fibers, they grew perfectly, rather than in the flat, misshapen way cells usually grow when placed in a glass petri dish. Soon Schindler was growing functioning, three-dimensional breast cells, stem cells and nerve cells in his lab on Donaldson’s fibers.

This spring, Meiners, a spinal cord injury researcher, decided to give the fibers a try. When she inserted them in the gap in her rat’s severed spine, its nerve cells grew over the fibers, connected the severed area and enabled the rat to walk again.

At least five more years of research are needed before anyone expects that the results of this lab work could be applied to humans. But the preliminary discoveries were encouraging enough to lead to a partnership with Schindler that is propelling Donaldson into the multimillion-dollar cellular science business for the first time.

Cell researchers and drug companies around the world are now studying Donaldson’s synthetic filter fibers. The Mayo Clinic, National Institutes of Health and 800 university labs have snatched up samples for their own cell experiments. And scientists in China, India, Australia, Israel, South Africa and across Europe are using Donaldson’s fibers to grow cell cultures.

“It’s a total hoot that fibers that make (Army) tanks go through the desert and that filter air in tractors can now be used for cell research,” Schindler said.

For Donaldson, the new demand for its filter material was entirely unforeseen.

“It’s just by coincidence that the fine fibers do mimic the … cellular matrix,” Donaldson spokesman Rich Sheffer said. “It was on our Donaldson website as a filtration enhancer.”

Donaldson created the product to go into the air filter systems it makes for Mack trucks, bulldozers, farm equipment, airplanes, factories and even Army vehicles. The fibers in the filters create a screen-like barrier that traps tiny pollutants. But Donaldson’s designers also unknowingly created a replica of the “cell matrix” naturally found in animals.

An online Google search is responsible for bringing Donaldson’s fibers to Schindler’s attention.

Long frustrated with how poorly mammalian cells grow on glass petri dishes, Schindler wondered if they might grow better on synthetic “nanofibers” that mimic what is naturally found in the body. Schindler hit the Internet to do more research. What he found surprised him.

“I came to the (Donaldson) website and said, ‘Oh, my God, this must be a Google mistake.’ There was an article about air filters showing nanofibers, but not for bioscience (use),” Schindler said.

Unlike plant cells, mammalian cells need a realistic structure to grow on, one that mimics the body. One look at what his Google search turned up sent Schindler reaching for the phone and Donaldson’s number.

When Schindler put a human breast cell on the Donaldson fibers for the first time, his microscope not only revealed that it had attached to the fibers and grown round and plump, just like it would in the body, but the cell even grew a hole in the middle, as normal milk-duct cells do.

It was “extremely dramatic,” Schindler recalled. “Right away I saw the difference, and that was striking.”

Schindler ultimately convinced Donaldson sales manager Tim Grafe that he wasn’t crazy or pulling a prank with this talk of filter material giving cells a new lease on life. They signed a confidentially agreement in 2003 that led to this year’s breakthrough into a new market for Donaldson.

Donaldson’s new division, which began operations last month, sells its flat fiber wafers for $70 a pack. Sales will be less than $1 million this year, but they should go higher as the company builds its profile in what is estimated to be an annual $100 million university research market and a $500 million pharmaceutical lab market, Grafe said.

Dr. Scott Nyberg, a Mayo Clinic liver transplant surgeon who has been trying to develop an artificial liver made of pig or rat liver cells, got his first sample of Donaldson’s nanofibers two months ago.

He placed liver cells from a healthy rat on the wafer and waited for the cells to start the usual bizarre mutations that had occurred in previous experiments. Instead, the cells kept their normal function and shape.

“It’s exciting,” Nyberg said. “It’s still early along to know for sure if it’s going to replace the (expensive) biological products that are out there … but I think this could make a huge difference.”


Posted on July 17th, 2005 in Research for a Cure.