In human medicine, stem cell research is a topic of controversy and conflict. But in the horse world, different approaches have allowed this exciting therapy to bypass heated debate and move into the realm of actual application. So far, the results have been worth cheering about.
What are stem cells?
Adult or somatic stem cells are found throughout the body and are used by the body primarily to maintain and repair tissue. One specific type, the mesenchymal stem cells (or bone marrow stromal cells), generate bone, cartilage, fat and fibrous connective tissue, such as tendons and ligaments.
Adult stem cells can be collected from many sites. This is in contrast to the embryonic stem cells—available only from embryos—that have caused so much debate in human medicine. In horses, stem cells are typically collected from one of three sites: fat, bone marrow and the umbilical cord.
Vet-Stem, Inc.—so far, America’s only commercial veterinary stem cell company—prefers to collect stem cells from a small sample of the injured horse’s fat. Vet-Stem sees this as a less invasive, less painful process than collecting bone marrow. What’s more, company founder Robert Harman, DVM, MPVM, says that fat tissue contains far more stem cells than bone marrow—a difference of 1 stem cell out of 50 cells in a fat sample vs. 1 in 100,000 in a similar bone marrow sample.
VetCell BioSciences, Ltd., a British veterinary stem cell company, collects stem cells from bone marrow and umbilical cords. They note that a veterinarian can remove a bone marrow sample using local anesthetic and standing sedation. The company also has technology that allows a stud farm or mare owner to collect stem cells from a foal’s umbilical cord and cryogenically store them for future use. VetCell has also developed a technique for multiplying the number of stem cells in a sample.
All three of these stem-cell sources have a distinct advantage over lab-created stem cells or those harvested from third-party embryos: Since they come from the horse’s own body, there is no risk of rejection when the stem cells are actually put to use.
What can stem cells do for horses?
Currently, stem cells are being used to treat equine tendon and ligament injuries, such as strains, tears or bows, and even some bone fractures. The key to their effectiveness is this: When transferred from one location to another, adult stem cells transform from the cell type of the original location (say, fat) to the cell type of the new location (say, a ligament). Thus, when injected into the injury site, stem cells are able to regenerate normal tissue, repairing the damage without scar tissue buildup. This is a dramatic improvement, since development of less-elastic scar tissue often leads to re-injury or prevents the horse from returning to its full performance ability.
In studies involving horses from a variety of performance disciplines, including jumping and barrel racing, Vet-Stem has recorded the following results, based on six-month follow-up surveys:
• More than 80 percent of patients had “favorable” or “very favorable” ultrasound results at one, three and six months.
• More than 80 percent of patients were considered “improved over traditional therapy” at one, three and six months.
• Three-fourths of all patients returned to full performance after six months.
Vet-Stem will eventually release return-to-performance results for racehorses, as well. Studies are also underway to evaluate the use of stem cells for treating other injuries and diseases. For instance, the San Luis Rey Equine Hospital is expected to work with the company this year to evaluate the effectiveness of stem cell therapy for spinal cord damage and joint repair.
What’s the process?
The procedure Vet-Stem uses for stem cell therapy in horses is fairly straightforward:
1. Your vet collects a sample of fat (about two tablespoons) from the injured horse’s tailhead.
2. The vet overnight-ships the fat sample to Vet-Stem.
3. Vet-Stem extracts the stem cells from the sample, preps them for use and sends them in ready-to-inject syringes back to the vet, again by overnight shipment.
4. The vet injects the stem cells into the horse’s injury site.
Vet-Stem recommends that the injection take place seven to 45 days after the injury. This allows the stem cells to begin regenerating normal tissue before the body begins developing scar tissue. The horse owner then works with her veterinarian to devise a suitable rehabilitation plan based on the individual horse and the specific injury.
Regarding cost, Vet-Stem suggests talking with your veterinarian for an estimate that would include stem cell therapy and any additional care needed for your horse’s particular situation. But, as a ballpark, the stem cell portion is in the range of $1,500 to $2,500 and depends on whether the ultrasound diagnostics are bundled in with the veterinarian’s charges. Vet-Stem points out that a similar procedure in humans costs in the range of $35,000 for treatment of cartilage damage.