Dr. Chad Schmiedt, a veterinary surgeon from the University of Georgia (UGA) Veterinary Teaching Hospital, and his colleagues have used mesenchymal stem cells from the fat of cats to optimize the acceptance of a new kidney in cats.
The recipient of this kidney transplant was a four-year-old flame point Siamese male cat named Arthur. Arthur’s owners brought him from Virginia to the University of Georgia after he was diagnosed with chronic renal failure about a year ago. Two other veterinary hospitals declined to operate on Arthur, since they did not deem this cat an optimal candidate for a kidney transplant. As it turns out, Arthur has trouble absorbing cyclosporine, which is the anti-rejection drug used to prevent the recipient of the kidney transplant from rejecting it.
In his initial consultation with Arthur’s owners, Schmiedt had the idea of using adult feline stem cells as a part of Arthur’s immunosuppressive protocol. There was precedent for this, since a cat that was operated on at University of Georgia Veterinary Teaching Hospital in 2013 had received a kidney transplant with doses of its own mesenchymal stem cells to prevent rejection of the transplanted organ. This cat was doing well one year after surgery.
“To the best of my knowledge, UGA is the only veterinary facility in the world to use adult stem cells in feline kidney transplantation,” said Schmiedt, who actually heads UGA’s feline kidney transplant program.”
Schmiedt continued: “We used feline adult stem cells in one other transplant that we did last year. A study published in 2012 found that the use of MSCs during renal transplant surgery i humans lowered the risk of acute organ rejection, decreased the risk of infection, and the patients had better estimated renal function one year after surgery.”
Mesenchymal stem cells can be harvested fat, bone marrow, and umbilical cord or placenta. Before the transplant surgery, Schmiedt isolated mesenchymal stem cells (MSCs) from Arthur’s fat and the UGA Regenerative Medicine Service grew the stem cells from the fat sample for use in Arthur after his surgery.
Arthur has his kidney transplant on May 15, 2014. The first surgery harvests a kidney from the donor cat (named Joey) and the second surgery transplants the donated kidney into Arthur. The UGA transplant program for cats requires that the donor cat be adopted by the recipient family’s family, which means that Joey and Arthur will become lifelong playmates.
“Cat owners who seek kidney transplants for their sick cats have to be very dedicated,” said Schmiedt. “They will give their car medication twice a day for the rest of its life. They also must be willing to take their cats to the veterinarian for frequent check-ups… a significant amount of time and expense is involved in keeping the recipient and donor cats healthy. But cat lovers who will go to this extent are willing to extend this kind of care to all cats they own.”
Apparently, Joey will be joined by Arthur and five other felines as well.
Stem cells do not replace the need for antirejection medication, and since Arthur’s body poorly absorbs cyclosporine, he will need to take a second antirejection drug as well called mycophenolate. Schmiedt, however, and his colleague stem cell scientist Dr. John Peroni sees MSCs making an important contribution to transplant medicine: “MSCs in veterinary species have been primarily used to treat musculo-skeletal injury – problems with bones, tendons, and joints – and those are our most frequent uses here at the UGA College of Veterinary Medicine. But there is good evidence to support using stem cells to modulate the immune system and regulate inflammation. So, the transplant setting might be another optimal use for these types of stem cells.”
In order to access the efficacy of MSCs in a transplant setting, controlled studies must be done. It is clear that transplanted MSCs do not improve kidney function, but they do seem to slow down the progression of kidney disease. Schmiedt thinks that benefits to patients are possible: “The only down side is harvesting the cells seven to 10 days ahead of the surgery, which adds to the cost of transplant procedure.”
Adaptation of this procedure to animals could smooth the path to making this procedure readily available in humans as well.