With veterinarians across the country training to use stem cells for tendon and ligament repair, a professor at the University of California, Davis (UC Davis) wants to take the technology a step further by applying them to chronic, cell-based diseases.
Richard Vulliet, DVM, is very early into the work. But he is optimistic about the evidence as it exists, of course, and he may have had a success.
Vulliet has treated four dogs with degenerative myelopathy with their own stem cells, which he prefers to call mesenchymal stem cells or pluripotent marrow stromal cells. The terminology has evolved and those names are more descriptive, he says.
The process works like this: Vulliet derives the mesenchymal stromal cells from bone marrow. The bone marrow aspirate is then filtered and plated (stromal cells adhere to plastic) because only about one cell in 100,000 is the proper mesenchymal stromal cell. He then cultures the cells into an enriched colony, and injects them back in.
He injects the cells systemically into the circulation because it appears that they home to an area of injury. Moreover, when the cells are injected directly into tissue, they tend to just clump there.
“We’re still in the exploratory phase,” he says. “When I talk to possible clients, I generally get the impression they think I know what I am doing. But no, this is research.”
Vulliet’s potential success is a dog named Turbo, a German Shepherd that belongs to his neighbor. A videotape of Turbo prior to treatment shows the dog trying to walk with little, if any, proprioception in its hind limbs. The dog careens and stumbles and hops to get along. At one point, Turbo falls right into Vulliet, who is holding the dog's leash.
That was in April. A videotape from July shows Turbo clamboring up into the seat of a pickup truck. Vulliet says Turbo was unable to do that prior to treatment.
The owner did not immediately tell Vulliet about the dog's improvement. It came out by chance during a conversation. "Oh, yeah, by the way, I forgot to tell you. But I think he is a lot better," Vulliet recalls the neighbor saying.
That kind of lax reporting is one of the pitfalls of doing the research the way Vulliet is conducting his. The conditions that he is interested in treating — the degenerative myelopathy common in German Shepherds, Rhodesian Ridgebacks and Pembroke Welsh Corgis as well as dilated cardiomyopathy common in Doberman Pinschers — have no experimental model. Therefore, he cannot use colony dogs, as is the usual practice in veterinary school research.
In fact, Vulliet isn’t even doing the research at UC Davis. He has rented a small, nondescript office in town, which he is paying for himself and with a $100,000 grant he received from the AKC Canine Health Foundation. The protocols he would be forced to adhere to at the university, working with pet dogs, would be too cumbersome, he says.
Because he is working with pet dogs, Vulliet says he is screening potential owners carefully. But it is not to determine if they will be conscientious reporters. He wants owners who have accepted that their pet’s condition is a fatal one and understand that his treatment is experimental. He says he wants owners who are going to be grateful if their dog gets any relief or improvement, because it might be very little.
Vulliet says he got interested in treating these conditions because he was working with mesenchymal stem cells and their interaction with connective tissue, and it was boring. Then he came across two papers.
In one of the papers, Japanese researchers described treating induced cardiomyopathy in experimental rats (Circulation 2005;112:1128-35). They reported that when the cells were injected into the myocardium, function improved, and there was evidence that the cells formed new vascular structures and produced collagen.
In the other paper, researchers at Tulane University in New Orleans induced spine injuries in experimental rats and treated them with mesenchymal stem cells. When they treated the animals immediately after the injury was induced, there was no apparent effect. However, when they waited one week before treating, they found that at five weeks, seven rats out of 12 could lift their trunks with their hind legs. By comparison, none of the 10 rats that were not treated showed similar signs of improvement.
Vulliet says notions of how mesenchymal stem cells might enhance the healing process have expanded beyond the idea that the cells migrate to a site of injury, differentiate into the proper type of cell and incorporate into the tissue. They might modulate immune response as well.
In the Tulane paper, researchers noted that microscopy showed that some of the injected cells had elongated and attached themselves to the injured areas where they appeared to be supporting the axons of the spinal cord. But they had not become axons. Vulliet suggests that they might be exuding tropic factors or growth factors, or they might be physically protecting the axons. Nobody really knows.
Of the four dogs with degenerative myelopathy that he has treated, one is far enough out from treatment to say that it definitely has not had any benefit, one has shown some signs of benefit, and two — Turbo included — seem to have been helped.
One dog was found to have a malignant tumor on its spleen, after it was treated. Vulliet says he did not note the tumor when the dog was examined before treatment, and it was large.
Vulliet has not treated any dogs with dilated cardiomyopathy. But he has been in contact with Doberman groups to recruit possible subjects.
Vulliet is not even far enough into his research to develop a protocol for collecting his data. Still, he hopes his work becomes a model. Most veterinary research done at veterinary schools uses dogs kept in a colony. Most animal research done for human medicine is done in rats. But there could be great advantages to using real animals living in a non-contained environment, he says.
Stem cells are an ideal entrée into real-animal research, Vulliet explains. Experiments with human subjects and stem cells are not generally allowed, and federal regulators are unclear about whether they have the authority to regulate such research, since the cells are not drugs and usually are autologous tissue.
There is nothing to hold back research with animals, apart from proper ethics and compassion, Vulliet says.
“I think we will learn more from these dogs than from the thousands of Ph.D.s who are experimenting in the labs,” he says. “If I can buy the dogs a few months of comfortable time, I will consider that a success.”
Feedback from colleagues has expressed concern regarding the nontraditional approach and discussion of VERY preliminary data.
This is very early work. That two of four patients appeared to improve is NOT proof of efficacy and neither Dr. Vulliet nor VIN New Service are making claims of efficacy.
Dr. Vulliet would like to find more patients to treat, but no one reading this should interpret these early results as proof of efficacy. It is very possible that this early result, that 2 of 4 dogs treated appeared to improve, is a chance result and not an effect of the treatment described.
These early studies are intended to fine-tune the methods involved and to assess whether larger, more controlled, trials should be pursued.