Stem Cell Therapy for Pets

Mike Zaremba, an operations manager for a software company in Denver, was desperate and searching. His dog Nakota, a three-year-old Siberian Husky, was in severe and chronic pain and could barely walk after an anterior cruciate ligament (ACL) surgery in February failed to achieve the desired result. The dog would hide in different parts of the house, he always had his head down, and he couldn't walk without limping severely. "The surgery went as well as it could have, so another surgery wasn't an option," says Zaremba. "But Nakota just wasn't healing. He was really suffering. I wanted so badly to help him, but I had run out of options."

When Zaremba's veterinarian told him about a new procedure in which Nakota's own fat-derived stem cells could be used to expedite the ligament's healing, Zaremba was skeptical but willing to try it. Within a few weeks after the minimally invasive procedure, Nakota was back to running long distances and jumping into the car with no visible sign of pain. "He's just like his old self again," Zaremba says. "It's unbelievable."

While humans are still waiting for stem cell treatments to become available, animals like Nakota already have a paw up. Poway, Calif.-based Vet-Stem, which touts itself as a world leader in veterinary regenerative medicine, has been using its licensed stem cell therapy in horses for three years and is now extending its commercial service to include dogs, who are treated with their own stem cells to repair tendons and ligaments. The first and only company in the United States to offer fat-derived stem cell treatments for commercial use, Vet-Stem has trained 65 board-certified small-animal surgeons to treat osteoarthritis. This fall veterinarians across the United States will be able to become credentialed users via online training at the company’s Web site.

Robert Harman, the privately held company's CEO and founder, is a veterinarian and former bio-tech executive who says veterinarians have used his company's procedure to treat more than 2,500 horses, including a number of world-class racehorses, and more than 200 dogs with arthritis and tendon and ligament injuries. "The animals return to their prior level of performance about 75 percent of the time," says Harman. "There's no question that this is working." Harman says the only adverse side effects have been swelling at the injection site in a small number of cases.

Harvesting stem cells has of course been a tricky and sometimes controversial business, especially from human embryos because of the accompanying moral debate. But with fat-derived (i.e., non-embryonic) cells—from either humans or animals—there is no such debate. And of course there are fewer restrictions and regulations for clinical trials on animals than on humans. With Vet-Stem's procedure, veterinarians collect a small sample (about two tablespoons) of the dog's own fat with a small incision, typically from behind the shoulder blade or from the belly. The fat is then overnighted to Vet-Stem, where the regenerative cells are isolated, and those cells are then overnighted back to the veterinarian in ready-to-inject syringes. The stem cells are then injected straight into the animal's joint or other area of concern.

While proponents of fat-derived stem cell therapy were considered mavericks just a few years ago, Vet-Stem's results, combined with data from a number of clinical trials worldwide, offer evidence that this is legitimate and promising science. Dr. Darwin Prockop, professor of biochemistry and director of the Center for Gene Therapy at Tulane University Health Sciences Center, has been researching non-embryonic stem cells for the past 14 years. Despite his early skepticism about fat-derived stem cells, he says that the potential uses for these and other non-embryonic stem cells are almost limitless. As Prockop explains it, the body heals itself, but sometimes it can't do enough. Stem cells boost the body's healing capability and could potentially be used to treat almost any disease. "These cells repair tissue; they have auto-immune and even anti-inflammatory properties," says Prockop, who is not affiliated with Vet-Stem.

The unlikely idea that animal and human fat might actually contain useful stem cells was first studied in a lab at the University of Pittsburgh in the late 1990s. Bill Futrell, former chairman of the plastic surgery department at that university, says his group, led by researchers Adam Katz and Ramon Llull, was interested in studying the potential uses of fat when the scientists had a revelation of sorts. "When [my researchers] came to me and told me, 'We can make bone out of fat,' I was excited but naturally skeptical," Futrell tells NEWSWEEK. "The medical dogma for so long had been that liver cells make only liver cells, etc., etc. We were disproving that dogma in our labs. We looked at this again and again and again, and concluded that this was real, and that it could be very useful."

Research at Pittsburgh (and also at UCLA) eventually led to the creation in 2002 of Vet-Stem by Harman, who had previously run HTI Bio-Services, a company that researched various technologies being developed by biotech companies and helped bring them to market. (UCLA and Pittsburgh have now gone to court over who owns the rights to fat-derived stem cell technology.) After Harman sold the company in 2000, a former client told him about the work of Futrell and his colleagues at Pittsburgh, who had apparently found regenerative stem cells in fat. With some 60 million dogs in this country alone, Harman reasoned that the potential for this technology's use in veterinary medicine, if it really worked, was staggering.

Veterinary experts have been watching Vet-Stem's research with interest. Dr. Beth Sebin, assistant director for education and research at the American Veterinary Medical Association (AVMA), says the organization encourages and supports animal and human studies of this new use of stem cells. "We don't endorse anything specifically, but we do think this is an exciting new area of research, and it does appear to work on animals with osteoarthritis and other joint problems," Sebin says. "There is peer-reviewed scientific literature that lends credibility to what Vet-Stem is doing. They are in the business of making money, of course, so we have to look at them closely. But the basic research seems to back up what they are saying. And it appears that this is all being done in veterinarian clinics in a humane and ethical manner. That's key for us."

As to cost, the procedure for dogs generally runs from $1,500 to $2,500, depending on the animal's overall health. So far Vet-Stem has performed this procedure on only a small handful of cats. "The problem with cats is that they hide their osteoarthritic issues," Harman says. "It's just not as commonly diagnosed." Though the focus is now on canines, the company is researching treatments for cats—especially those with kidney disease, which is a common problem without many solutions. Harman says they plan to start trials next year for feline kidney disease, as well as liver disease in dogs.

As groundbreaking a technology as this appears to be for pets, it could be directly translatable to humans, insists Harman, whose company is exclusively veterinary. "It won't help my business, but I really believe this technology should be fast-tracked for humans," he says.

Tulane's Prockop, who calls Vet-Stem's work with animals "encouraging," advocates a more cautious approach with people. He believes those trials should start with patients who are terminally ill—people who have few other remaining options. "We're still not certain why these cells sometimes work and sometimes don't," he says. "When placed into human tissue, they work kind of like a drug store. But they act differently depending on what type of tissue they are placed in, and we're still learning why that is." Currently, clinical research in the area of fat-derived stem cell use in humans is underway at major institutions such as Tulane, UCLA and the Texas Heart Institute.

Among the more promising human trials is one conducted last year in Japan with cancer patients who have had breast reconstruction after lumpectomies. The data from that and other studies in Europe is expected by the end of this year. For this fat grafting procedure, stem cells extracted from fat, usually from the abdomen, are mixed with regular fat and then injected into the area of the breast that needs filling out. (Ordinary fat grafts are often reabsorbed by the body or die before they can develop a viable blood supply.)

Cytori Therapeutics, a regenerative medicine products company in San Diego, has already initiated a clinical trial in Europe testing stem cells derived from fat in humans for patients suffering from an inadequate supply of blood to the heart, or chronic myocardial ischemia, and the company is about to begin trials in heart attack patients as well as for breast reconstruction. Researchers at Cytori have invented a device that allows physicians to take fat from human patients at their bedside, remove the stem cells from the fat, and treat patients with those cells in real time. The device has already been approved for use in Europe beginning in 2008. Cytori chief financial officer Mark Saad says the company hopes to win approval for the device in the United States within the next few years. In the meantime, American pet owners will have yet another option in the growing array of high-tech health treatments for pets.