Transplants for Pets: The New Frontier
Although potentially lifesaving, the procedure has physical and ethical consequences for owners and animals.
Joanne Healey Howl, DVM |
Posted: Sat Feb 10 00:00:00 PST 2001
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After a battery of tests, Chloe was accepted into Dr. Mathews' programs. The university found two potential donors, both healthy young Beagles from a research facility. Both Beagles had been scheduled to be destroyed within weeks but were freed to help Chloe instead. Beagle A, later named Alfred, was chosen as the donor. Beagle B, whom everyone called Bernard, served as backup. Both were given the same battery of tests as Chloe - lots of blood work, temperament testing and ultrasound examinations of their kidneys. All three dogs were prepared for surgery, which took nearly a full day for Dr. Mathews and her technical staff.
"The morning after the surgery, Chloe was a different dog," Tozzoli said. "She had a sparkle in her eye, and her tail was wagging; she felt great. She had been such a sick little thing just the day before. After all my worries, I just couldn't believe it!" Chloe recovered quickly although her schedule has been grueling at times; she gets medicine twice a day and has seen her veterinarian sometimes as often as every other day. She's a long-term survivor, celebrating her two-year surgical anniversary on Oct. 1, and will turn 13 on Valentine's Day. The two years have been almost a 20 percent extension of her life, 16 to 20 human years. Her Beagle buddies are survivors, too. Before any dog can undergo surgery, its owner must find a home for the donor. Tozzoli placed Alfred with one of her best friends - a great match for a loving Beagle. Bernard was destined to return to his research facility, but Tozzoli purchased his freedom, and the staff at Guelph placed him with loving owners. The surgery saved three lives.
In just the past 10 years, research at the University of Guelph has opened the door into the darkness of canine organ transplantation, but it's only the first crack of light. "My dogs aren't dying of rejection now," Dr. Mathews said. "I have quite a few that have lived five years or longer. But they do die of infection and some from cancer." Both are the result of long-term immune-system suppression. To avoid infection, transplanted dogs, such as Chloe, can't mingle with other dogs - no kennels, no groomers and only the most cautious walk in the park. Even a touch of kennel cough can kill. For organ transplantation to go forward, researchers need to find the delicate balance between suppressing rejection and leaving the dog's immune system healthy enough to fight off infections.
One way to reach this balance is to wean dogs slowly from immune-suppressive drugs, hoping the body eventually tolerates the new organ, which is how Dr. Mathews is attempting to solve the problem. Another approach is to find a drug that is more selectively immune suppressive, targeting organ rejection without wiping out all immune function. This is the hope of Dr. Gregory and his team at the University of California, Davis. "We showed years ago that a drug called leflumonide along with cyclosporine prevented renal allograft rejection between unmatched dogs," he said. "One of those dogs never did reject the kidney - it died of liver failure about seven months after transplantation." At the time of these studies, the drug was undergoing scrutiny for Food and Drug Administration approval for use in humans, so it was not available for dogs. Beginning in October, however, Dr. Gregory expected to start a clinical trial of the drug in dogs. He has high hopes for success.Page 1 | 2 | 3 | 4
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