Stem cells helped heal a dog's crippling injuries - maybe

Bernie has recovered nicely from critical burns to his paw pads. His treatment included injection with stem cells.
Bernie has recovered nicely from critical burns to his paw pads. His treatment included injection with stem cells.
Posted: October 03, 2011

It looked like a miracle, or at the very least a breakthrough. A pit bull stranded on a searing rooftop until his paw pads were burned off is now doing well, mostly healed after being injected with stem cells as part of a new treatment.

However, the story is not as it first appeared when it received widespread coverage last summer. Some experts say the dog's new skin is probably his own. The stem cells might have created a protective barrier during healing, but they probably did not graft onto the dog's paws.

The bigger question is whether the stem cells did any good, or whether this dog, named Bernie by his rescuers, would have healed just as well without them. Is it a triumph of technology or just the amazing power of physiology?

On July 19, the temperature was well over 100 in Reading. Animal-control officers found Bernie alone on an asphalt tile rooftop. He had also reportedly burned his back and his underside in what must have been a desperate effort to keep the searing heat from further eating through his paws.

Neighbors reported that he was trapped on the roof for 10 hours before his rescue, said Barry Pease, president of the Animal Rescue League of Berks County. The owner was never found.

By then the dog had third-degree burns on every paw pad. In a "before" picture, his paws looked as raw as hamburger. A shelter veterinarian treated him with sterile dressing and fluids before bringing the dog to Boyd Wagner, a veterinarian at Wyomissing Animal Hospital.

"I gasped," Wagner said. "I'd never seen anything that severe before." The shelter workers feared they might have to put the dog down because of his pain, he said.

Wagner said one of his clients ran Celavet Inc., which creates stem-cell treatments for animals. It makes stem cells, he said, that have been used to treat joint problems in dogs and horses.

Because the company had no FDA approval to use the stem cells for burns, Wagner asked if he could obtain them on a compassionate basis. He sent the FDA pictures of the dog's raw, angry skin, and the agency gave its approval, provided that he documented the animal's progress.

On July 26, Wagner put Bernie under general anesthetic and injected Celavet stem cells into all pads. "At first his paws were more inflamed than before, but then they started healing," Wagner said. He replaced the dressing on Bernie's paws every Monday, he said, each time charting his condition.

The company website says the cells it makes act like so-called embryonic stem cells, which have received huge attention in human medicine because they can be transformed into all types of tissue - bone, skin, lung, intestine, muscle, liver or brain - depending on where they are implanted. They are usually taken from excess embryos created during in-vitro fertilization and routinely discarded from fertility clinics.

Since the late 1990s, when human embryonic stem cells were first isolated, they have been the object of hope for everything from heart disease to spinal cord injury, but also the subject of controversy, since some consider human embryos to be human beings.

The cells injected into Bernie's paws were not embryonic stem cells but fetal ones, said Oleg Kopyov, Celavet's executive vice president. The company, based in Oxnard, Calif., refused a request for an interview, but in an e-mail, Kopyov wrote that the cells were derived from dog and cat fetuses and were cultured in a patented process.

The cells, he wrote, have been shown to repair tissue without eliciting an immune response. "Our cells seem to be embryoniclike in their ability to differentiate into almost all cell types," he wrote. Bernie was the first animal to be treated with such cells for burns.

His veterinarians consider him recovered enough to be adopted. The shelter workers will start searching for a new owner Monday.

The stem cells may not have been necessary for Bernie's recovery, said John Gearhart, director of the University of Pennsylvania's Institute of Regenerative Medicine and one of the first to isolate human embryonic stem cells.

From examining the company's literature and pictures of the dog's paws, he concluded that the new skin was unlikely to have been made from the stem cells. The cells may have helped to produce a protective covering, but Bernie's paws in the after pictures are most likely covered in his own skin.

"Ultimately, was this animal helped or harmed?" Gearhart asked. "That's the key question."

Stem cells can provide a protective covering and even supply some growth factors that can promote healing before they are sloughed off, he said. Stem cells have had similar beneficial effects in human burn victims, he said, as have synthetic materials used as temporary coverings.

Penn dermatology professor George Costarelis had the same skeptical reaction to the images before and after treatment. In the before pictures, he noted that the dog still had some skin around the wounds and this might have been capable of slowly growing slowly over the injured site.

The stem cells may have covered the wound temporarily, Costarelis said, but he agreed that they probably had been rejected and replaced with the dog's own skin.

"I'm skeptical this is any different from what would have happened if the dog had good wound care" without stem cells. With no controlled studies, he said, it's impossible to know.

Gearhart said very little mention exists in scientific literature on the type of stem cells Celavet makes. The company's brochures and news releases state that they act just like embryonic stem cells, he said, but he said there was too little information provided to know for sure.

Researchers at Penn are competing with Celavet and other companies to create stem-cell therapies to repair torn ligaments and other internal injuries in racehorses, he said, in "a big-money game." In those uses, Gearhart said, the stem cells do not necessarily form new tendons, for example, but simply aid in the healing of existing ones.

The publicity surrounding stem cells has made the public "nuts," he said. Desperate people contact him all the time, the most emotional of whom are seeking treatments for their animals. "There's a long history, from the animal side of things," he said, "of clinics popping up that take advantage of folks."

Not that Celavet would necessarily fit into this category. After all, Bernie's treatment was an act of charity.

"I'm not saying that some procedure like this would or could not work for Bernie," he said. "But what's needed are bona fide, confirmed data."


Contact staff writer Faye Flam at 215-854-4977 or fflam@phillynews.com. Read her "Planet of the Apes" blog at www.philly.com/evolution.

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