Page 109 - March_2022

EQUINE HEALTH
“In the future I think we will get better at selecting cells that have enhanced functionality for different conditions. We will be better at matching different types of cells with different disease conditions—so we can select the best possible formulations.” - Dr. Thomas Koch
Equine Mesenchymal stomal cells adherent to plastic culture ware during cell expansion in vitro.
other product (Arti-Cell Forte) contains cells from the peripheral blood of adult horses- -isolating cells from the blood, using my initial protocol for umbilical cord blood, since these also work for adult blood,” he explains.
“These cells are characterized by their abil- ity to adhere to certain types of plastics. In the lab we use plastic culture dishes and receive
the cells into those. In the first few days a lot
of cells are just floating in the media and don’t attach, and then some start attaching to the plastic. When we replace the media and aspi- rate it off and replace it with fresh media, this gets rid of all the floating cells. We end up with a cell population stuck to the plastic and the media is clear; there are no more floating cells because we have diluted them out,” says Koch.
After eight to 12 days some of the cells on the dish start to form colonies and expand and undergo cell division. “We use enzymes to lift them off the plastic; the enzymes cleave the binding between the cell and
the plastic without damaging the cells. We harvest them this way and split them, put- ting them from one flask into three to five flasks of the same size. Those cells reattach and keep growing and propagating. We can eventually grow them into billions of cells,” he says.
The original cells from umbilical cord blood come from breeding farms. “I work
with some high-end Standardbred and Thoroughbred farms in southern Ontario. During foaling season, they have eQcell’s col- lection kit at the farm, and whenever a foal is born, the attendant clamps the umbilical cord. Then when the foal stands up, the cord simply breaks at its natural breaking point. With the clamp across it (toward the mare side) the blood is not gushing out from the placenta through that break and is saved.”
Then the attendants use a blood transfusion bag to collect it. “These bags come preloaded from the company, with anticoagulant and a needle welded onto the end. The attendants simply clean the cord and put the needle into the blood vessel within it, and the blood can flow/drain into this collection bag. It’s non- invasive; you are not poking the mare or the foal—just saving the blood that would other- wise drain out and be lost.”
The infusion bag can be stored in a refrigera- tor overnight, then shipped by FedEx to the lab. “Even a day or two later, when it arrives at our lab, we can successfully isolate those cells. What’s nice about this source of cells is that they are as young as we can get them, and consistent. All our cells are from newborn foals, and mares that have no signs of disease during the pregnancy.”
There are advantages to having these very young cells. “If you get cells from fat (adipose) tissue or blood or bone marrow from adult horses, they may be somewhat damaged. All cells in the body become damaged as we get older. They age, so even if you have a healthy, normal animal, there are many stringent requirements for donor testing. Cells from an adult will be different,” he says.
With foal cells, the allogeneic cells have some variability between one foal and another, but these cells are still more consistent. “This is another advantage of allogeneic cells over autologous cells; we have the luxury of time, to work with these cells and apply different selec- tion criteria. We can standardize and optimize our cell products because we don’t use every cell,” he explains.
By contrast, with autologous cells you get what you get. “They may grow well, or they may not, but you have no alternative. If you want to use them, you simply have to use what you get. They may not be optimal; maybe the horse has other conditions that affect the functionality
of those cells. This is part of the problem with autologous cells, even though you don’t have immune issues. There may be other issues with those cells that affects their functionality.”
With allogeneic cells, it may be inconsistent in terms of whether horses develop antibod-
ies against them. “So far there have been very few adverse reactions to them. We know these cells don’t stay around very long in the tissues, so they are getting recognized as foreign by
the immune system and being removed by the body, as we would expect. But in spite of that, they seem to have a therapeutic effect,” he says.
The way they work is like a conductor of an orchestra. “The stem cell comes in and influences other cells in the body—in the joint or tissue. These cells are influenced by the stem cell and start to behave differently. Even though the stem cell gets removed by the
immune system, there is a lasting effect in the tissue of the patient’s own cells behaving dif- ferently. This is probably why we see enhanced repair of those tissues. Some of those cells that are behaving differently are macrophages. They may be in an inflammatory state, but the stem cells communicate with those macrophages, and they switch and become an anti-inflam- matory type of macrophage. These cells are not rejected by the immune system because they are the patient’s own cells. Those changed cells will stay around longer in the body and exert their therapeutic effects.”
The stem cells come in and have this echo- ing ripple effect throughout the tissue even after those stem cells have been removed. “In the future I think we will get better at select- ing cells that have enhanced functionality
for different conditions. We will be better at matching different types of cells with different disease conditions—so we can select the best possible formulations,” he says.
SPEEDHORSE March 2022 107
Dr. Thomas Koch, Ontario Veterinary College,University of Guelph