Stem-cell therapy proving successful in horses

stem-cell therapy shows promise for racehorses

jpatton1@herald-leader.comApril 23, 2011 

Anyone who has witnessed an on-track breakdown knows the sport of Thoroughbred racing is tough on horses, on owners and on fans. With hundreds of fatal injuries every year, there is more than enough heartbreak.

But for every fatal breakdown, there are dozens of minor injuries that can wreck a horse's career and an owner's budget.

Now, new treatment methods in regenerative medicine using stem cells could save careers and even lives.

Take the case of SandSunSea, a 3-year-old colt by the late Pleasant Tap, bought for about $90,000 at a yearling sale in Canada.

His trainer, Roger Attfield, elected not to try racing him at age 2. "He was a horse that I gave time to because he was a big growing boy," Attfield said. At 3, the colt was coming along nicely but then suffered a torn flexor tendon in his right front leg.

"He was just about ready to run when this happened. ... He was acting like he was going to be a nice horse," Attfield said. "I was just starting to get a little bit excited about him, he was doing so well. That's usually when they get hurt, when you feel that way."

Such an injury normally would take nine months to a year to recover from, and the horse might re-injure himself once he finally goes back into training.

Attfield turned to stem-cell therapy. He shipped the horse from Payson Park training center in Florida to Woodford Equine Hospital in Versailles, where Dr. Joe Yocum removed a bit of the horse's tissue one morning in March.

At the MediVet labs, which opened earlier this year in Nicholasville, 1.2 billion stem cells were pulled from 30 grams of fat taken from SandSunSea. The stem cells — which are simple cells in the body that can develop into any one of various kinds of cells, such as blood cells, skin cells, etc. — were "activated" to switch on the natural healing properties. That afternoon some of the cells were injected back into SandSunSea's leg. (The rest are stored frozen at the MediVet lab in case more treatments are needed one day.)

The results surprised even Yocum, who is a partner in MediVet America, one of a handful of companies around the world that offer stem-cell therapy to veterinarians.

"I went back after two weeks and scanned him and could hardly even find the lesion," Yocum said. "He looks perfect, really."

Normally it might take four months for the lesion to gradually disappear, he said. "This thing was practically obliterated in two weeks."

The horse, now at a rehab farm, has begun light exercise. But the technology is so new that nobody really knows the best way to proceed, and they don't want to push him too hard.

"Everybody's really interested in this," Yocum said. "I don't want to oversell it, like snake oil, but I think it really has some merit."

Attfield, now in Kentucky for Keeneland's spring racing meet, agreed. He had tried stem-cell therapy before on other horses, but this was his first adipose-derived (which means "from fat") treatment.

Now he's sold. The difference, he said, was amazing. "It's quite incredible," Attfield said.

He thinks SandSunSea might make it to the races one day after all. "He's got a pretty good fighting chance, if this works," he said.

Different from older treatments

So much is riding on an injured horse's recovery — can he come back to the track, or will he need a new home as a riding horse? — that many horse owners are willing to attempt a treatment that could cost $2,400.

"It'd be very cheap if it worked," Attfield said. "Sometimes, no matter how careful you are with these animals, they get hurt anyway.

It's just a frustrating part of the business."

Older stem-cell therapies relied on cells pulled from bone marrow, sometimes from donor animals.

But Jeremy Delk, co-owner of MediVet America, which has its North American headquarters in Nicholasville, said his company's technology gets a higher stem-cell yield from fat, which can improve outcomes. And by using the animal's own cells, the treatment eliminates many risks.

Delk said stem-cell therapy holds great promise for horses as well as dogs and cats.

"How many horses, possibly Kentucky Derby runners, get debilitating injuries that there was no treatment for," Delk said. "That's what this can change. ... There are so many horses that are suffering from these injuries, and we can possibly give them a second chance."

Small animals, too

Stem-cell therapy has had success treating soft-tissue injuries and arthritis and other joint diseases in horses, degenerative diseases in dogs, and internal medicine problems such as kidney disease in cats.

Delk said the lab in Nicholasville is designed to help vets, particularly small-animal practitioners who don't have the resources to extract stem cells at their offices.

The first animal to benefit was Bernie, an 11-year-old St. Bernard mix with arthritic knees.

Dr. Catherine Donworth, who treated Bernie at Romany Road Animal Clinic, said the costs (about $1,500 to $2,000 for a dog) are comparable to years of anti-inflammatory medication, but with very little risk.

That would mean a lot to most pet owners. "Pets are members of the family," she said. "The best case is we'll have a dog who's got his quality of life back. Preliminary studies are that it lasts for years."

Effective for laminitis?

Stem-cell therapy also offers a potential path to one of the holy grails of horse medicine: an effective way to battle laminitis.

The painful disease of the hooves is extremely difficult to treat, let alone cure.

Although most people remember 2006 Kentucky Derby winner Barbaro's heartbreaking injury in the Preakness, it wasn't the broken leg that killed him. The bones eventually healed but by that time his other feet had succumbed to pressure-induced laminitis and Barbaro was humanely euthanized.

Laminitis claimed the great Secretariat, as well as Pleasant Tap, sire of SandSunSea.

Delk said MediVet is actively researching how the therapy could help laminitic horses.

"Stem cells aren't a cure-all," he said. "We've treated laminitis cases with a lot of success, but it's still very early."

But there have been glimmers of hope.

In October 2009, the racehorse Thorn Song was as about as close to dying as a horse could get. Every conventional treatment for laminitis had been exhausted. In fact, the insurance company paid off on a $2.75 million mortality claim.

"He was deemed to have almost zero chance at survival," California vet Dr. Doug Herthel told The Blood-Horse.

But as a last-ditch effort, Herthel tried stem-cell therapy using bone marrow. (Herthel is not affiliated with MediVet; he has a stem-cell lab at his practice, Alamo Pintado Equine Medical Center in Los Olivos, Calif.)

Herthel thought the horse had less than 10 percent chance of making it, but, almost miraculously, within weeks the damaged hoof began to regrow.

The treatment worked. Thorn Song's life was saved, and this spring he successfully covered his first mare, Clouds of Glory, who is believed to be in foal.

Life not only saved, but created.

"That shows the power of what these cells can do," Delk said.

Reach Janet Patton at (859) 231-3264 or 1-800-950-6397, Ext. 3264.

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