Researchers Explore the Digital Cushion

Researchers at Colorado State University used 16 saddle horses to investigate the biomechanics and cellular structure of the digital cushion (DC).

The horses were involved in an earlier experiment that included creating a forelimb carpal joint lameness, resting the horses for 2 weeks, then exercising them on a treadmill 6 minutes a day, 5 days a week for 8 weeks. The horses were examined for lameness, then sacrificed 70 days after the beginning of the study, so tissues for both studies could be obtained for testing and examination.

Core samples of the DC were taken from a palmar location inside the heel bulbs and a second, more dorsal position just behind the navicular bone. The samples were tested in a hydraulic press to measure elasticity and examined microscopically.

There were no measured differences in the elasticity of the DC samples or their microscopic, cellular structure and tissue composition between the lame and non-lame limbs. The DC tissue from the dorsal location closer to the navicular bone had a higher elastic modulus than the tissue from the palmar location. This area also had more ground substance, a gel-like material that fills the spaces between cells and fibers in connective tissue, compared with the palmar location.

These results should not be surprising, given that the relatively short duration of the lameness may not have allowed time for the DC to remodel in response to the lameness. Also, as one might expect given different remodeling forces likely act on the structure at different locations, the DC tissues were not homogenous in their microscopic structure.

— Damone J et al. JEVS 2024;142:105178

How Endurance Horses Fare in Nutraceuticals Trial

Researchers in Italy conducted a randomized, controlled feeding trial of a supplement containing natural, plant-based antioxidants, vitamin C and omega-3 fatty acids that was advertised as having antioxidant and anti-inflammatory properties.

Eleven Arabian endurance horses in active training were evaluated with a 15-minute trot and 60-minute gallop exercise test, including measurements of heart rate, red blood cell antioxidant capacity and blood chemistries such as blood lactate and creatine kinase performed before and after the 21-day feeding trial.

None of the blood lactate or heart rate variables were different between the treatment group and controls. Creatine kinase (a measure of muscle activity and damage) was significantly lower in the treatment group after the feeding trial, while red blood cell oxidative capacity was significantly increased. Unfortunately, no direct measures of inflammation were reported for the experiment. The supplement was palatable with no adverse effects noted.

— Stucchi L et al. JEVS 2025;146:105364

Cisplatin Could Cause Laminitis

Although considered a hazardous chemotherapeutic agent, topical Cisplatin has been safely and successfully used under bandages following surgical debridement to treat equine hoof canker.

In this study from Austria, researchers tested the safety of an arterial perfusion of the lower limb containing Cisplatin with an eye toward using this approach to treat canker. Thirteen limbs were collected from an equine slaughter plant and immediately prepared for arterial perfusion using an oxygenated solution formulated to support cellular functions. Cisplatin was added to the solution for the limbs in the treatment group, while a solution without Cisplatin was used for the controls. Dorsal hoof wall samples were collected and evaluated microscopically.

The primary and secondary epidermal lamellae appeared normal after the treatment. However, there was significantly decreased laminin staining in the treatment group, indicating damage to the basement membrane that was not seen in the controls. Although this study was not conducted in live horses, the authors were confident that even short-term exposure of the laminar blood supply to Cisplatin would compromise the basement membrane and significantly increase the risk of laminitis.

— Reinthaler B et al. JEVS 2025;150:105598

Polyacrylamide Gel for Arthritis

Two recently published studies of polyacrylamide hydrogel for arthritis in horses shed light on its safety and efficacy.

The first, supported by the product’s manufacturer and conducted by veterinarians involved with the manufacturer, examined the safety of administering the polyacrylamide gel intra-articular treatment concurrently with a second corticosteroid injection to one fetlock of 10 healthy horses.

Each horse received a single injection and was examined for complications six times over a course of 30 days. No adverse events occurred, and all the horses remained sound with no signs of joint swelling or lameness.

The second study, conducted by researchers in Europe, surveyed 160 sports medicine and rehabilitation veterinarians in the U.S. and Europe to gauge their satisfaction with the treatment for chronic synovitis or arthritis, usually used when other treatments had failed.

Most of the respondents (52%) reported complete recovery for more than half of their patients. Partial or temporary recovery was reported for 25-50% of cases. Most respondents (about 75%) reported at least some improvement in most (about 75%) of their cases with worsening of clinical signs reported for a few (less than 10%) of their cases. The median overall satisfaction score for the treatment was 8/10, which seems particularly high for a treatment most often used after others have failed.

While neither of these studies was particularly rigorous with the outcomes selected for evaluation, they were both well designed and meticulously reported. Combined, they support the use and continued investigation of polyacrylamide gel as a treatment for chronic arthritis in the horse.

— Whitaker B et al. JAVMA 2025;263:460-467 and Pluim M, Frippiat T. JEVS 2025;150:105610