New Research Provides Clarity Around the Treatment of Equine Osteoarthritis

The Study Compared the Concentration of Alpha-2-Macroglobulin in Pro-Stride® APS, Restigen PRP® and Alpha 2EQ® Devices

Zoetis Inc. completed a recent study investigating alpha-2-macroglobulin (A2M) and other prominent proteins in regenerative medicine devices that help manage equine osteoarthritis (OA), including Pro-Stride® APS, Restigen® PRP and Alpha2EQ® devices.

Results from the direct comparison were completed in partnership with leading research universities and an independent veterinary practice. The multi-center study provides insights and increased clarity about the concentration of A2M in devices used for the management of equine osteoarthritis.

Two clear findings emerged from the study:

  1. The plasma output volume, A2M concentration and plasma protein composition was equivalent between the three devices. The 30mLs of platelet-poor plasma generated by the Pro-Stride APS and Restigen PRP devices contained the same concentrations of 16 plasma proteins (including A2M) as the final output of the Alpha2EQ device.1
  2. In addition to the platelet derived growth factors and white blood cell derived anti-inflammatory cytokines contained in the cellular output of Pro-Stride and Restigen, the A2M concentration was significantly higher than the final plasma output of Alpha2EQ.1

“This research provides guidance for equine veterinarians seeking a comprehensive option to help manage osteoarthritis for horses entrusted in their care,” shared Dr. Nathan Voris, Director of Equine Technical Services at Zoetis. “Our team is proud to invest in studies designed to help improve the profession’s understanding around the composition and therapeutic benefit of our orthobiologic devices. “The clinically relevant data from this, and other recent studies, illustrates that Pro-Stride and Restigen concentrate a variety of anti-inflammatory cytokines, growth factors and plasma proteins that are beneficial in addressing very complex diseases like osteoarthritis and soft tissue injuries,” concludes Dr. Voris.

The research was completed in partnership with Veterinary Medical Schools at the University of Pennsylvania and Colorado State University as well as a private equine practice in Missouri. The Zoetis Animal Health Research and Development team completed the mass spec plasma protein analysis in Kalamazoo, Michigan.

“Managing osteoarthritis calls for a comprehensive mix of plasma proteins, anti-inflammatory cytokines and anabolic growth factors,” explains Kyla Ortved, DVM, PhD, DACVS, DACVSMR, Associate Professor of Large Animal Surgery, University of Pennsylvania School of Veterinary Medicine. “Effective therapy requires addressing multiple disease pathways, so a cellular component may be essential along with plasma proteins. This study helps affirm the concentration of A2M with laboratory verified data; veterinarians have found success with the Pro-Stride APS device in the field and the research results help support our understanding of the components of each device.”

Osteoarthritis is a complex biologic process that affects many horses as they age. A targeted approach that takes on multiple disease pathways is needed to help manage pain and promote healing. Zoetis’ Pro-Stride and Restigen devices are comprehensive therapies for the management of osteoarthritis and soft tissue injuries. Pro-Stride and Restigen, together with CenTrate® BMA (horse bone marrow aspirate device), make up Zoetis’ family of regenerative medicine devices to help manage equine lameness.

In 20 minutes or less, a Pro-Stride device can be used to help produce a concentrated solution of cells, platelets, growth factors and anti-inflammatory cytokines to help reduce pain and manage osteoarthritis. Processing can take place right at the farm, stable or clinic and it has been shown to improve a horse’s lameness grade for up to one year after a single injection, and in some cases even longer.2,3

A summary of the research can be found online here. Contact your local Zoetis Equine Specialist or call 1-888-ZOETIS-1 with questions.

On Thursday, November 30, Zoetis Equine hosted an in-person sunrise session with the American Association of Equine Practitioners (AAEP) in San Diego, Calif. Panelists included researchers directly from this study who spoke to their work and key learnings.

Learn more about Zoetis Equine’s Regenerative Medicine Device portfolio.


  1. Zoetis Data on File: 23EQRGRMD-01-03. 2023.
  2. Bertone AL, Ishihara A, Zekas LJ, et al. Evaluation of a single intra-articular injection of autologous protein solution for treatment of osteoarthritis in horses. Am J Vet Res. 2014;75(2):141-151. doi: 10.2460/ajvr.75.2.141.
  3. Muir R, Reisbig N, Baria M, et al. The concentration of plasma provides additional bioactive proteins in platelet and autologous protein solutions. The American J of Sports Medicine. 2019;47(8):1955-1963.


About Zoetis

As the world’s leading animal health company, Zoetis is driven by a singular purpose: to nurture our world and humankind by advancing care for animals. After innovating ways to predict, prevent, detect, and treat animal illness for more than 70 years, Zoetis continues to stand by those raising and caring for animals worldwide – from veterinarians and pet owners to livestock farmers and ranchers. The company’s leading portfolio and pipeline of medicines, vaccines, diagnostics and technologies make a difference in over 100 countries. A Fortune 500 company, Zoetis generated revenue of $8.1 billion in 2022 with approximately 13,800 employees. For more information, visit

The Zoetis Equine division is committed to providing horse care you can count on. Our team includes numerous equine veterinarians and other experts who are inspired daily by the opportunity and profound responsibility to support horses, the owners who love them and the equine veterinarians and other care team members who safeguard their well-being. Whether at the clinic or in the field, Zoetis is always by your side with a comprehensive, innovative portfolio of equine products and services at every step of a horse’s care and throughout the journey of a horse’s life. Visit to learn more.

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