Stem cell research has become one of the hottest, most divisive of political topics in the human research field, but to researchers at the University of Guelph, it means optimism, especially for horses facing career-ending cartilage injuries.
Stem cell therapy - Hit or miss for horses?
Researchers from the Department of Biomedical Sciences, don't dismiss stem cell products as the âsnake oilâ variety, but they do advise caution and ask for patience when it comes to their use in horses.
Currently, stem cells are being used experimentally and commercially in cell-based transplantation treatments for the horse. Since 2002, commercial companies from the US and UK have been marketing regenerative medicine, selling products containing stem cells in either a non-purified or purified form, respectively.
Dr. Dean Betts and doctoral candidate Dr. Thomas Koch, Ontario Veterinary College (OVC), researchers from the Department of Biomedical Sciences, don't dismiss these products as the 'snake oil' variety, but they do advise caution and ask for patience when it comes to this burgeoning science.
"We believe that stem cells hold great promise for therapeutic use in horses. We are optimistic, but are also in the early days," says Koch, formerly a veterinarian in Denmark. "We need more study and research on the efficacy and safety of stem cell and tissue engineering treatments."
So, what makes the stem cell so special, and does the 'buzz' warrant an investment in excess of $4.5 billion (US dollars) in human research and development? In the horse industry, it means BIG business!
Currently, there is no effective long-term treatment to repair a cartilage injury in the joint, one of the leading causes of early retirement in performance horses. The tissue from the cartilage heals extremely slowly and the damaged (or missing) tissue is often irreplaceable, usually leading to osteoarthritis. Enter stem cell therapy.
A stem cell is a cell that can copy itself, divides extensively and with 'encouragement' - can diversify itself into a new tissue (such as cartilage). This new tissue may then be transplanted into the joint, replacing the damaged or missing tissue.
This sounds amazing, but there's one major problem!
The stem cells do not easily adhere to the surrounding healthy cartilage or bone, especially when the horse bears weight on its legs. "Currently, there is no feasible transplanting method in existence for horses' joints," claims Betts. "In horses, it is impossible to keep them immobile, so it is necessary to devise some way of holding the cells in place."
"We are looking into the potential of modifying the mosaic grafting technique of bone or cartilage, pioneered by Dr. Mark Hurtig here at OVC, to keep the transplanted tissue in place for the healing process to begin in the joint."
In conjunction with experimenting in potential grafting techniques, Betts and Koch are investigating the best and most practical kind of stem cells to be used as part of this procedure.
There is a common assumption that the source of stem cells is the embryos of unborn fetuses. While the 'ultimate' stem cell does come from the early embryo, there are other sources for these desired cells including; bone marrow, fat tissue, umbilical cord tissue and umbilical cord blood.
Betts and Koch are focusing on stem cells taken from the umbilical cord blood of the horse. "Cells taken at birth are younger and have better capabilities of dividing and creating different types of tissues," explains Betts. "Also, younger cells are less likely to be rejected when transplanted to heal cartilage." He adds, "Taking stem cells from the blood of the umbilical cord is non-invasive and more practical than from an embryo."
To date, Betts and Koch have found that the blood from the umbilical cord contains mesenchymal stem cells - cells that are the building blocks of bone, cartilage, fat, muscle and tendon. This important discovery is encouraging to Betts and Koch, and confirms that they are heading down the right stem cell path.
"It is currently unknown whether stem cells used in horses have therapeutic effect since the cells are generally combined with other biological factors," states Koch. "Now, we need to prove that it is indeed the stem cells that are causing the perceived improvements and how the cells cause the effect. Once this is achieved, this research may eventually lead to the production of conventional regulatory-approved drugs."
Perhaps someday, when your horse recovers from a severe joint injury, you will be thanking researchers like Betts and Koch. Perhaps another day later, when you have an injured knee or shoulder repaired with stem cell replacement therapy, you'll be thanking a horse!