A team of Colorado State University scientists and a syringe of her own stem cells helped Rio get her groove back.
"She saw the barrel, and it was Katy bar the door," said Linda Ghent of her 18-year-old mare's division-winning run earlier this month in the Mile Hi Barrel Horse Association's winter series finale in Castle Rock.
In August 2007, the door to racing had closed on Rio. The stoic animal had shown no gimpiness at all, but when Rio crashed into a barrel during a race in Craig, Ghent knew there was trouble.
Rio had torn the cartilage and connective tissue in her back-right stifle, which functions much like the human knee and is essential to the stops and turns demanded by the sport.
Such injuries are often career-enders for performance animals, such as those competing at the recent Denver's National Western Stock Show, Rodeo & Horse Show.
Rather than perform the usual surgery to remove the damage and then hope the scar tissue holds, CSU equine surgeon Laurie Goodrich took the problem to Dr. John Kisiday, a faculty member and bioengineer doing stem-cell research.
Bone marrow was harvested from Rio's sternum with a stout needle, distilled to the stem cells in Kisiday's lab, grown for two weeks in a petri dish and reinjected into the horse.
Rio could have been ready for the barrel course within a year of the treatment, but Ghent kept her out of the arena for two years.
During a checkup this week, Rio - short for Miss Re Olena - galloped with ease across a concrete floor at the CSU Veterinary Teaching Hospital breezeway, not seeming to mind as Goodrich twisted and bent her leg to check for swelling.
"This is cutting-edge stuff," said Ghent, who lives in Loveland. "And we're fortunate that it's going on right here in our own backyard."
A short time later, in a cavernous operating room nearby, Good rich attended to another quarter horse. This one was out cold, flat on its back on a massive padded operating table, its legs splayed and its inner right leg shaved.
Using a two-chamber needle similar to that used to mix epoxy - with stem cells on one side and a gluelike substance made from the horse's blood on the other - Goodrich delivered the slow but deliberate injection as staff and students assisted.
Stem cells have been the focus of a CSU clinical study since 2005. In 2008, the Steadman-Hawkins Research Foundation gave the university $250,000 to extend the work.
Rio was one of the first horses to undergo the treatment at CSU, but hundreds more horses and dogs have since recovered from joint, tendon, ligament and cartilage injuries that might have left them lame.
Success, Goodrich said, depends on the severity of the injury, and her goal is high: getting the animal back to the same level of performance as before the injury.
The work led to a spinoff business for Kisiday. His company, Advanced Regenerative Therapies, collects injured animals' stem cells, grows them and ships them back to veterinarians across the U.S. and Canada.
Kisiday said the procedure for growing human stem cells is the same as techniques for growing animal ones. It is unrelated to the controversial use of embryonic stem cells for biomedical research.
Last year, the U.S. Food and Drug Administration said it will take more study and licensing before the stem-cell treatment used at CSU can be used in humans.
Until such work is done, animals are carrying the scientific weight.
The $2,400 treatment seems steep next to the $3,500 Ghent paid for Rio when the horse was 5. But a few years later, as Rio collected prize after prize, Ghent was offered $70,000 for the mare.
It was a small price, she said.
"I want her to run as long as she wants to," Ghent said. "And after that, she'll be a pasture ornament."
