Where do the stem cells for clinical research come from?
When stem cells come right from the patient into whom they are later injected, they are called autologous cells. If they come from another dog, they are termed allogeneic cells.
With autologous cells, a doctor harvests some tissue from a dog — either a bit of bone marrow or fat tissue — then sends that tissue to a lab, which isolates the stem cells from the tissue and cultures, or grows, them. Then they are injected back into the dog. Immune rejection of such cells is the least likely because they came from the patient to begin with.
The process of growing stem cells in a lab after tissue has been taken from a dog takes about three or four weeks. That would make such cells fine for use in treating a chronic disease like, say, arthritis. But if there’s an emergency — a fracture or life-threatening infection — and none of the patient’s stem cells have been stored, allogeneic stem cells harvested from another animal would have to do.
At Tufts, for research purposes, there’s an animal stem cell bank with “a growing number of dog cells,” says veterinarian Andrew Hoffman, Director of the Regenerative Medicine Lab at the Cummings School of Veterinary Medicine. They can be used for research on the very dogs from whom they were taken or on other dogs. The chance of rejection of such cells by a dog in whom they did not originate is small. The type of stem cells used travel quite well one from one dog to another. (See main story.)
Stem cell research currently taking place at Tufts includes a trial to see if the cells can have a positive impact on a life-threatening skin disease, at least two different autoimmune diseases, and tendon injuries. There is also a study that is looking at how new combinations of chemotherapy drugs impact stem cells that initiate and then live within cancerous tumors. A lot of tumors possess these “cancer-initiating stem cells,” contributing to tumor growth and malignancy, and in some cases even constituting the entire tumor,
Dr. Hoffman says. Thus, if you can inhibit the growth of those cells with a particular grouping of chemotherapeutic agents, “you might be able to knock out the whole tumor. Mammary cell tumors would be one example” of the kinds of cancer the research is targeting, says Dr. Hoffman.