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Study: Psoriasis And Supporting Limb Laminitis Show Similar Immune Response

For many horse owners, laminitis is one of the worst diseases a horse can get. Triggers for the condition are varied; laminitis can occur on its own or it can be triggered by another serious issue, like colic or a retained placenta–which are emergencies in themselves. To add insult to injury, supporting-limb laminitis can devastate a horse that is already favoring another leg.

Supporting limb laminitis is extremely painful and is generally a complication of orthopedic injuries and infections. Horses with the condition are often euthanized.

A horse that is experiencing supporting limb laminitis has an increase in cytokine production that promotes inflammation. Drs. Lynne Cassimeris, Julie Engiles and Hannah Galantino-Homer sought to locate the specific cells in the immune system that secrete cytokines; it's hoped that this discovery would help them find therapeutic interventions for the disease.

The research team focused on the proinflammatory Interleukin-17A (IL-17A) pathway. IL-17A is generally activated when the horse experiences a cutaneous wound or pathological skin condition; this response is similar to how humans react to a wound or skin disease—specifically psoriasis.

To test their hypothesis, the team used lamellar tissue from Thoroughbreds that had been euthanized because of naturally occurring standing limb laminitis. They compared these samples to euthanized horses that didn't have laminitis.

The scientists found IL-17A and the target genes in the tissue of laminitic horses, especially when compared to the tissue of non-laminitic horses. They report that finding a way to block the activation of IL-17A could lead to the development of a therapeutic treatment for supporting limb laminitis.

The team notes that this will not be as simple as applying human therapies to horses, as successful psoriasis treatments in humans use monoclonal antibodies to block IL-17A activation. These antibodies may not work in horses for a variety of reasons, including that they may not bind to the equine receptor. In addition, this treatment would most likely be cost prohibitive.

With more research, local inhibition of the IL-17A expression may be possible.

Read the full study here.

Laparoscopic Surgery May Prevent Recurrence of Nephrosplenic Entrapment

Nephrosplenic entrapment is a type of colic that occurs when a horse's colon shifts and settles over the nephrosplenic ligament, trapping the colon and its contents, which causes distention and pain. Nearly 9 percent of colic cases seen in equine clinics are caused by nephrosplenic entrapment.

Though it's unclear what makes some horses more prone to the condition, it's suspected that a large abdomen, abnormalities in how a horse's colon moves and the shape of the nephrosplenic space may play a role.

There are several treatments for nephrosplenic entrapment, including administering medication to shrink the spleen and then working the horse to try to get the colon back to a normal position. Anesthetizing a horse and rolling him back and forth to try to free the colon can also be done. Finally, surgery may be performed to manually free to the colon.

Though most horses with nephrosplenic entrapment recover, nearly 21 percent of survivors will experience another entrapment. The University of Pennsylvania's New Bolton Center found that a surgical procedure to close the nephrosplenic space can prevent the entrapment from occurring again.

Veterinarians can tack surgical mesh over the top of the spleen, which keeps the colon from slipping into the space. This can be done laparoscopically in about 30 minutes and has no risk of failure. Veterinarians looked at the records of 26 horses that had experienced nephrosplenic entrapment that had the space closed with mesh: not one horse had a recurrence during the follow-up period, which was up to seven years.

Horses That Pass In-Hand Inspection May Not Complete XC Phase Of Eventing

A recent study has used a horse-behavior scale to identify high-level event horses at risk of poor cross-country performance. Drs. Sue Dyson and Andrea Ellis completed two studies: one was a preliminary study that used 35 horses competing on the second day of dressage at the 2018 Burghley CCI 4*. The main study used 70 horses warming up for dressage at the 2019 Badminton CCI 5* horse trials and 67 horses warming up for dressage at the 2019 Burghley horse trials.

Each horse was observed for between 10 and 12 minutes by Dr. Sue Dyson while they warmed up. She then she applied the Ridden Horse Pain Ethogram (RHpE) to determine if the horse was pain-free and recorded her findings. The RHpE uses 24 behaviors to determine if a horse is experiencing musculoskeletal discomfort.

The behaviors include tilting the head, swishing the tail, staring for more than five seconds, spooking, rearing, bucking, exposing the tongue, moving the ears back for more than five seconds, clamping the tail or opening the mouth and separating the teeth for more than 10 seconds.

A horse that exhibits at least eight of the behaviors is believed to have a musculoskeletal issue. The more behaviors he shows, the more pain he is most likely experiencing. The most frequent score a non-lame horse garners is 2 out of 24; the study shows that a score of seven or more in four- and five-star equine competitors was more reliable to identify horses whose performance may be impaired because of pain.

The duo then compared RHpE scores for the competition horses to final results in terms of dressage penalties, cross-country performance, showjumping penalties and final placings. They found a moderate correlation between dressage penalty scores and the RHpE score; the correlation was much more pronounced in the cross-country phase: 10 of the 17 horses (59 percent) with an RHpE score of 7 or more failed to finish the cross-country phase; 39 out of 117 horses (33 percent) with a score below 7 failed to finish.

The team found no relationship between the RHpE score and showjumping performance. However, there was a significant relationship between total RHpE score and final horse placings, with horses having higher RHpE scores being placed lower than horses with low RHpE scores.

The scientists concluded that top-level competition horses at three-day events can pass the preliminary in-hand horse inspection, but show signs of lameness when ridden and demonstrate the behavioral changes assessed with the RHpE. Though there are many reasons a horse-and-rider team may not complete the cross-country phase of eventing competition, there is a strong correlation between horses that exhibit behaviors on the RHpE and a failure to complete. This indicates that underlying musculoskeletal discomfort may be a contributory cause to not finishing the cross-country phase of eventing.

Read the article here.

Miniature Horse Has Complete Hip Replacement

Veterinarians at the University of Liverpool have totally replaced the hip of a Miniature Horse. Duncan arrived at the clinic in July severely lame in his hind leg; a CT scan showed that he had dislocated the left hip joint and damaged the head of the femur beyond repair.

Duncan's vet, Dr. Dave Stack, discussed treatment options with some small-animal surgical specialists. As Duncan weighed under 200 pounds, they felt that a total hip replacement was an option to offer pain relief and a good quality of life.

The procedure had been tried before in small ponies but had failed. To be a success, teamwork between equine and small animal surgeons was paramount; anesthesiologists and internal medicine were also integral to a successful outcome.

The surgery team placed a hip implant used on large dogs in Duncan. The gelding stayed in the clinic for over three weeks and required 24/7 supervision. He also required intensive physiotherapy to return to normal function. He is now able to walk and trot almost normally, the vets report.