by Kentucky Equine Research Staff

A proof-of-concept study revealed that a novel intra-articular nanogel infused with medications, referred to as an intra-articular drug delivery system, is a promising therapy for horses with osteoarthritis.^* If effective, nanogels, also called hydrogels, could halt disease progression, restore joint function, and improve mobility.

According to the research team, a functionalized nanogel containing bioactive molecules serves two purposes. First, the nanogel, which contains hyaluronic acid, provides joint lubrication and has other viscoelastic properties. Second, it serves as a drug delivery system, capable of providing the sustained release of biomolecules possessing analgesic, anti-inflammatory, anticatabolic, or pro-anabolic features that are key to the long-term management of osteoarthritis.

“To date, nanogels have been studied in vitro, in a laboratory setting, showing positive features such as chondroprotection and cartilage-building effects,” said Catherine Whitehouse, M.S., a nutrition advisor for Kentucky Equine Research. “A small study in healthy horses was also conducted showing no adverse events associated with the gel.”

In the current study, the researchers used a functionalized nanogel in eight horses diagnosed with naturally occurring OA of the fetlock or coffin joint. Horses were all used for international level competition, including showing jumping and three-day eventing. All horses showed grade two or three lameness (out of five), and radiographs disclosed a combination of joint space narrowing, osteophyte formation, subchondral bone sclerosis, and synovitis, all hallmarks of osteoarthritis.

The nanogel used in this study was functionalized (i.e., changed with a specific intent in mind) with two compounds: endoethelin type A and bradykinin B1 receptor agonists that have anti-inflammatory and chondroprotective properties.

A single injection was administered at the start of the study, and horses were evaluated at week two. If horses were sound on soft ground and had a lameness score of two or less, they were instructed to gradually return to full workload by week six. Full follow-up examinations including radiographs and ultrasound exams were performed at week six by the researchers, and referring veterinarians submitted lameness video evaluations at week twelve. Referring veterinarians also reported lameness status twelve months following the injection.

Key findings included:

• The functionalized nanogel was well tolerated with no major adverse events following Mild, self-resolving joint swelling occurred in two horses.
• At week six, one horse returned to competition, two resumed training, and three were in full flat work.
• At week twelve, seven of the eight horses had improved lameness scores compared to baseline: four by one grade and three by two grades. Two horses had complete resolution of lameness.
• Four horses achieved a return to the same competition level as before the onset of lameness. One horse also returned to the same highest level of competition but competed at fewer events. One horse returned to a lower level of competition, and two horses were retired.
• Of the six horses that remained in competition, no recurrence of lameness was reported, and no additional treatments were performed for the OA between week twelve and the last follow-up.

These results show a relatively delayed but prolonged clinical effect. This nanogel therefore demonstrates “promising potential for long-lasting return to competition.”

“Steps can be taken early in an athletic horse’s life to help protect its joints. Multiple studies have shown that offering oral joint health supplements containing glucosamine and chondroitin sulfate have a prophylactic effect, helping maintain joint function,” said Whitehouse.

Read more: Arthritis in Horses: Use of Intra-Articular Nanogels

Serena Heppes explains how to safely adjust the stirrups and girth while mounted. This is a educational and safety video brought to you by the Certified Horsemanship Association (CHA) For more information on the largest certifying body of riding instructors and barn managers in North America, Certified Horsemanship Association, please visit www.CHA.horse. To find a certified equine professional or accredited equine facility near you, visit www.CHA.horse

Read more: Adjusting the Stirrups and Girth While Mounted with Serena Heppes