Kidney, Bone Marrow Transplant Procedure Successful without Ongoing Drugs
The first client-owned patient who underwent surgery is shown here with her owner and veterinary technician Jonathan Mahoney. Standing (l to r) are Drs. Clint Lothrop, Michael Tillson and Pat Rynders with Tammy Hanson (kneeling).
Veterinarians from Auburn University have found a way to trick a dog’s immune system so that it accepts a kidney transplant without the ongoing use of immunosuppressant drugs. The key may be in the bone marrow.
Clinton Lothrop, DVM, PhD, DACVIM, was conducting bone marrow transplant research, his specialty for the last 15 years, when he discovered “almost by accident that bone marrow transplants induce tolerance for renal allograph.”
Over the last five years, Lothrop and Michael Tillson, DVM, MS, DACVS, and other college faculty members have performed simultaneous hemopoietic stem cells (taken from bone marrow) and kidney transplantation on 41 dogs. At press time, five procedures had been performed on client dogs from across the country that presented with end-stage renal disease. To date, there has been an 80 percent success rate. The first client dog was operated on about 90 days ago and is doing well with a steady reduction of immunosuppressive drugs. One patient did not respond to the transplantation but Lothrop said the dog had a zero chance of survival without the surgery. Nationally end-stage renal disease and renal failure are among the top three reasons dogs are euthanized, Lothrop said.
Lothrop and Tillson are the first to use this non-myloablative protocol in dogs, which requires a surgeon and internist working closely together “to provide extra level of nursing care for immunosuppressed dogs,” said Lothrop. As a result, the procedure may only be available at veterinary schools and large referring hospitals for the near future.
This procedure has not been tested on cats because of the existing protocols for surgery and the fact that feline kidney disease is easier to manage medically, Lothrop said.
On average, the procedure lasts four to six hours and costs between $8,000 and $12,000, depending on the size of the dog and length of hospitalization. Dr. Tillson has not found it necessary to remove the kidneys in client animals, and places new kidneys near the bladder. In comparison to surgery, immunosuppressant drugs for dogs with renal disease cost $600 to $1,000 per month, which makes the surgery, “almost a no brainer from the client’s perspective,” Lothrop said.
Patients receive a non-myloablative dose (200 rads) of radiation to suppress their immune systems immediately before the transplant surgery and they remain on immunosuppressive drugs for at least 60 days. After that time the drugs are incrementally reduced.
Recovery includes a two- to four-week hospital stay though kidney function can return in a week to 10 days. In some dogs function returned to normal in two days, Lothrop said.
“It [the bone marrow procedure] educates the body that it [the new kidney] is acceptable immunologically, which enables the body to tolerate it,” Lothrop said. “It has been a real team effort to perfect the medical aspects of this procedure.”
Drs. Lothrop and Tillson started their research with litter mates but now use totally unrelated dogs for transplants. “We’ve been encouraged by our research thus far,” said Tillson, “and we are hopeful that we will see similar results with our client-owned patients.”
Once the surgery is completed, the dogs have more in common than kidneys because Drs. Lothrop and Tillson expect the owners of transplant patients to adopt donors. “We want both the recipient and the donor to benefit from the transplantation process,” said Tillson. “And the donor dogs should live healthy lives with one kidney. Our ultimate goal is to work through shelters or rescue operations. Anyone who’s going to transplant their dog is going to be a great owner.”