Stem cells and Platelet Rich Plasma (PRP) as treatment methods for equine injuries seem a far cry from treatments of old – but the use of such therapies is increasing as the veterinary world embraces new methods to help sport horses return to their jobs.
Therapies to encourage regeneration of injured tissue were the focus of December’s 12th annual World Stem Cell Summit at the Palm Beach County Convention Center in Florida, where researchers, biochemists, veterinarians, and equestrians got together to learn more.
Several veterinarians from the Palm Beach Equine Clinic, including Dr Robert Brusie, Dr Jorge Gomez, and Dr Richard Wheeler, hosted a question and answer session at the Summit, addressing how regenerative medicine is changing and benefiting clients.
What Are Stem Cells?
Stem cell therapy can be used for many soft tissue and intra-articular problems, including severe cartilage damage, meniscal disease, tendon/ligament pathology, or any injury where the veterinarian would want to encourage a regenerative response. Stem cells can decrease re-injury rates in tendon bows, yield improved outcome in horses with meniscal tears, and may also have benefit when used in regional profusions for laminitic horses. Stem cells help to orchestrate an improved repair process in the site of injection and have anti-inflammatory properties.
How Can You Collect Stem Cells?
There are three different ways to collect stem cells from the horse. The first comes from bone marrow origin, where a collection of bone marrow from the sternum in a standing procedure. The bone marrow is sent to the lab for processing and expansion, which expands the cells up to a predetermined number (generally between 10 to 20 million cells).
Stem cells can be procured from harvesting fat. The veterinarian may extract a significant quantity of fat from around the tail head and gluteal region of the horse. The fat will be processed in the lab, stem cells in the fat are concentrated, and the cells are re-injected into the injury site.
The third option is to acquire allogenic stem cells, meaning stem cells from another animal of the same species. University programs offer commercially available stem cell lines where anywhere from 10 to 30 million stem cells are shipped for use the next day.
PBEC’s Board-Certified Staff Surgeon, Dr Weston Davis, is one of the top surgeons that has made clinical advances in stem cell therapy. Commenting on the three methods of obtaining stem cells, Dr Davis said: “I think the advantage of the bone marrow cells is that they are the most researched version of stem cells. The nice thing about the fat cells is that you can basically harvest the fat, process it, and inject it back on the same day.
“The allogenics are noninvasive to the horse that you are performing the procedure on. You don’t have to do a pre-surgical procedure to get your cells; you just call up and have your cells the next day to implant.
“One of the unique properties of stem cells is that they do not have immunologic markers, so if you inject the cell into another horse, that horse does not recognize that it is foreign. So generally speaking, there is no immune reaction to implanting the cells into another horse.”
There are also different methods of implanting the stem cells into the horse at specific areas of interest. “If we were treating a meniscal injury or cartilage damage in a joint, implantation would be as simple as a joint injection technique. If you are going to implant cells into an injured tendon or ligament, then we will most often do an ultrasound guided technique where we watch and direct the needle precisely into the lesion so we can put these regenerative cells right into the damaged area.”
How Does Platelet Rich Plasma Work?
Another therapy that can be applied on its own or in conjunction with stem cell therapy is the use of Platelet Rich Plasma (PRP). Platelets are very small blood cells that are a crucial part of the body and play an integral part in the blood clotting process to stop hemorrhaging from any wound. Because platelets are among the very first cells to accumulate at an injured site, they are very important orchestrators and stimulators in the repair process. Platelets contain granules filled with growth factors (the elements that aid in healing) and stimulate specified tissue to heal at an increased rate.
In order to treat a horse with Platelet Rich Plasma, veterinarians take a sample of the horse’s blood and concentrate the platelets in a high-speed centrifuge. This harvest and processing procedure takes about 30 minutes. The concentrated platelet rich sample is injected back into the horse at the specific area of injury using sterile technique and guided by ultrasound.
PRP treatment has had great success in tendon and suspensory ligament injuries and increasingly used in the treatment of intra-articular joint injuries. It can also be used following surgery in the joint to encourage a faster healing response.
“We harvest a large quantity of blood, anywhere from 60 to 180 milliliters, and we process that to concentrate the segment that is very rich in platelets,“ Dr Davis said.
“We get a high concentration of platelets – we are hoping for five to eight times the concentration that you would get from normal blood – then we take that platelet rich extract and inject it back into an injured area to encourage a more robust healing response. Whenever you have an injury, platelets are one of the first cells that get there. They will aggregate, clump, and de-granulate. They release these granules, which are very rich in growth factors, and signal the body to start the healing process.”
Cost is one thing that dictates the difference in the use of stems cells versus PRP for many owners. PRP tends to be more economically affordable, while stem cells can be a more expensive and aggressive therapy.
What New Technologies Are Available?
Both stem cell and PRP therapy are cutting-edge in the horse world now, as veterinary medicine researches how to further use the body’s own healing mechanisms to repair injuries. These regenerative therapies are part of a continually advancing field that has made exciting developments in both human and equine sports medicine.
“There is constantly new research,” Dr Davis said. “They have done some of the initial studies looking at the efficacy of both. Right now they are working on ways to refine their use. We want to get higher platelet yields out of our PRP, and we are tweaking the properties of the PRP to modify the number of white and red cells for particular injuries.
“For stem cells, they are researching different matrixes to apply them with, so that the cells integrate better at the injection site. Then they are working on triggering the stem cells, and trying to put in signaling cytokines or chemicals to make them differentiate to the specific cell type that you want. Actually directing the stem cells to become the exact type of cells you want is definitely still in its infancy, but it is on the horizon.”