When it comes to equine joint health, there are a lot of things being actively researched. In honor of Joint Health Awareness Month, we talked to two of the smartest veterinarians we know to find out what new joint health research they’re most excited about. Here’s what they had to say:

Lydia F. Gray, DVM, MA
Staff Veterinarian/Medical Director, SmartPak
Joint supplements are commonly used to proactively support healthy tissues in horses and to address discomfort in the joints of actively working or aged equine. While many owners are convinced of the benefits of joint supplements, based on the results they or their friends have seen, veterinarians often prefer an evidence-based approach such as this recently published study:

Watts, AE, Dabareiner R, Marsh C, et al. A randomized, controlled trial of the effects of resveratrol administration in performance horses with lameness localized to the distal tarsal joints. J Am Vet Med Assoc. 2016 Sep 15;249(6):650-9.

Who did the study?
A team of veterinarians from the College of Veterinary Medicine & Biomedical Sciences at Texas A & M University undertook a randomized, blinded, placebo-controlled clinical trial. Their goal was to determine the effect of giving resveratrol, the antioxidant found in the skin of red grapes, to performance horses with hock lameness.

How did they do the study?
41 client-owned horses finished the study, 21 in the treatment (resveratrol) group and 20 in the control (placebo) group. Horses that came to the College for hind limb lameness or poor performance were offered enrollment in the study if otherwise eligible. They were subjectively graded for lameness with and without joint flexion using the 0 – 5 AAEP Lameness Grading Scale, objectively graded for lameness using the Lameness Locator®, and re-evaluated for lameness after a nerve block of the more severely affected hind leg. All horses received steroid injections in both hocks and were instructed to rest the horse and give “bute” for 3-7 days. In addition, owners were given either the resveratrol-containing supplement or a placebo and instructed to give it twice a day. At 2 months, owners were asked to fill out a questionnaire, and at 4 months, owners were asked to fill out the same questionnaire as well as bring their horses back to the College for a re-evaluation of the lameness.

What did the study find?
Horses that received joint injections and the supplement containing resveratrol were significantly less lame on the basis of objective criteria (ie Lameness Locator) and subjective criteria (ie rider assessment of horse performance) than were horses that received joint injections and the placebo. This suggests that supplementing with resveratrol may be beneficial in horses with hock lameness.

Andris J. Kaneps, DVM, PhD, Dipl ACVS and ACVSMR
Kaneps Equine Sports Medicine and Surgery
Beverly, MA

Stem cell treatment is becoming more commonly used for treatment of joint and soft tissue injuries in horses. Stem cells are commonly obtained by drawing marrow from the breast bone. Because stem cell numbers in this type of sample are very low, it is sent to a laboratory for culture and proliferation, then returned to the veterinarian for injection in the same animal (referred to as autologous stem cells). This process may require three to four weeks. Stem cells derived from donors are available overnight (referred to as allogeneic stem cells) and can be injected in the affected joint within days. The aim of the paper summarized below was to determine if donor stem cells are as safe as autologous stem cells when injected in equine joints.

Ardanaz N, Vazquez, FJ, Romero A, Remacha AR, et al. Inflammatory response to the injection of mesenchymal stem cells in an equine experimental model: effect of autologous, and single and repeat doses of pooled allogeneic cells in health joints. BMC Veterinary Research 2016; 12:65.

Who did the study?
The study was conducted by a team of researchers based in Spain from the Laboratory of Genetics and Biochemistry and Department of Orthopedic Surgery and Traumatology, University of Zaragoza, and the Department of Animal Medicine and Surgery, Autonomous University Barcelona. The group undertook a blinded, randomized, placebo-controlled experimental study in normal horses. The goal was to determine the effects of autologous stem cells, donor stem cells and balanced electrolyte fluid injected in equine joints.

How did they do the study?
Six horses had joints injected with a single autologous dose of bone marrow derived stem cells and two separate doses of donor stem cells pooled from several horses. The second donor stem cell injections were made at least ten days after the first donor injection. Control joints in each horse were injected with balanced electrolyte fluid. Signs of joint inflammation and lameness were evaluated at days 0, 1, 2, 3, 5 and 10 after injection. Total protein, white blood cell count and neutrophil count in joint fluid were also measured at the same time-points.

What did the study find?
A mild increase in joint fluid volume without associated lameness was observed after all stem cell injections. The second donor stem cell injection caused the least amount of joint fluid increase. Laboratory parameters indicative of mild inflammation increased from day 1 to 5 for all stem cell (autologous and donor) injections. All clinical and joint fluid laboratory parameters returned to normal by day 10 and at that point were equal to joints injected with balanced electrolyte fluid.

Joint injection of donor stem cells caused the same level of inflammation as stem cells obtained from the treated horse. Repeated injection of donor stem cells did not result in an adverse response, in fact, there was less inflammation following the second donor injection. This research supports the use of donor stem cells that are available much sooner for treatment of a joint compared to autologous stem cells.