Sunday, December 29, 2019

Research identifies possible shock wave treatment markers

Extracorporeal shockwave therapy (ESWT) is used to promote healing of injured tendons and
ligaments. Using high-pressure sonic waves, ESWT is thought to increase blood flow to the treated area. It has been shown to reduce pain for several days after treatment.

This can cause problems if pain is masked before healing is complete. Overworked minor injuries could lead to major ones or even pose the risk of catastrophic life-threatening breakdown.

Competition authorities have introduced restrictions on horses participating after treatment. For example, the British Horseracing Authority banned the use of ESWT on the day of the race or on any of the preceding five days.

However, it’s one thing to restrict the use of ESWT; quite another to enforce a ban, as the therapy leaves no trace. That is, until now.

A team led by Mary Robinson, director of the University of Pennsylvania’s Equine Pharmacology Research Laboratory, and lab member Jinwen Chen has found that the practice does in fact leave a trail. In a paper in Equine Veterinary Journal, they report finding potential biomarkers of ESWT that, with further testing, could one day be used to enforce the ESWT ban.

"Because it's not a drug--it's applied to the surface of the skin--it's just not an easy thing to detect," says Robinson. "After a lot of trial and error, our study was able to measure changes in levels of five inflammatory factors, some of which we could detect up to three weeks after the shockwave therapy."
The search for these biomarkers dates back roughly a decade.

"It was Dr. Lawrence Soma, my predecessor, who said the lab was going to have to look at blood-based or urine-based biomarkers to try to detect shockwave therapy," Robinson notes.

To find the fingerprints that ESWT might leave behind, the researchers tested the therapy on 11 horses kept as a study herd at the University’s New Bolton Center. The researchers collected blood samples from the group of horses, composed of Thoroughbreds and Standardbreds, at several times both before and after each received a single dose of ESWT to a leg.

Over the years, the lab investigated various potential biomarkers - molecules that would indicate a horse received ESWT. They targeted 10 pro-inflammatory and anti-inflammatory signaling molecules, called cytokines, which they can measure from the blood using a sensitive test called ELISA, short for enzyme-linked immunosorbent assay.

"We looked a week before giving the shockwave therapy to see if there were any changes in the baseline period, due to changes in time of day or anything else, and didn't see anything we could define as significant," Robinson says. "And in the post-shockwave period we went out to three weeks."

No changes were detected in five of the cytokines they examined. But the other five-- TNF‐α, IL‐1β, IL‐1RA, IL‐6 and TLR2 – were significantly affected by EWST.

Of those, TNF‐α levels were significantly increased through the whole of the three-week post-therapy study period.

More study is necessary, Robinson emphasizes, before these biomarkers could be used to assess inappropriate use of ESWT in racehorses. For one, the researchers would like to see if measuring these same molecules in horses that are actively training and racing or that have an acute injury might change their results.

For that, she and her colleagues are actively pursuing follow-up studies to look at these biomarkers and other indicators using a biobank of samples from client-owned animals, including injured and active racehorses, treated at New Bolton Center.

The end goal is to keep the sport safe.

"Shockwave therapy is great as long as people rest the horse after using it," she says. "We are concerned that it's being abused in the racehorse industry and that it could potentially result in breakdowns. That's exactly what we're trying to avoid."

For more details, see:

Inflammatory mediators are potential biomarkers for extracorporeal shockwave therapy in horses
J.‐W. Chen, D. Stefanovski, J. Haughan, Z. Jiang, R. Boston, L. R. Soma, M. A. Robinson
Equine Vet J (2019)

Sunday, December 22, 2019

New asthma research in horses finds possible link to latex

A study into the causes of severe equine asthma (sEA) has revealed associations with over 113 substances, including latex found in artificial surfaces.

Lead researcher Sam White found that natural rubber latex was among ‘the most surprising and significant’ of several new allergens present in the dust horses breathe.

The study used advanced computing power to assess 400 potential allergens in over 130 sEA-affected and healthy horses, working with research groups in Switzerland, France, Canada and USA.

The study revealed several previously suspected allergens, such as pollen, mould and insect proteins, are likely involved in sEA, but the most surprising finding was the implication that natural rubber latex might also play a role. In fact, four of the five most significant allergens associated with sEA were latex proteins. The fifth was a protein from Aspergillus fumigatus, a common fungus previously linked with sEA. Until now, latex had not been tested due to limitations associated with classical allergen assessment methods.

White, now based in Nottingham Trent University's School of Animal, Rural and Environmental Sciences, carried out the study for the Royal Agricultural University (RAU) and the University of Nottingham.

The research used mathematical modelling to allow diagnosis of sEA from a blood sample, avoiding the need for more invasive diagnostic techniques currently employed.

He said: “The most significant and surprising allergens associated with sEA were from natural rubber latex. Latex is historically associated with the equine environment in the form of artificial surfaces on arenas and racetracks.

 “The high level of respirable dust associated with training on these surfaces has already been linked with chronic bronchitis, inflammation and oxidative stress in riding instructors, and latex has long been associated with a variety of respiratory conditions in humans.

“These early results show it could be linked to respiratory problems in horses too, although it is too early to make a firm conclusion based on these data.” 

He added that further research is needed to establish the levels of latex horses are exposed to in their environment, and the effects it has on them.

White said the identification of new allergens would improve allergen avoidance and inform future diagnostic tests and therapies. 

 For more details, see:

Antigen array for serological diagnosis and novel allergen identification in severe equine asthma
S. J.White , M. Moore-Colyer, E. Marti, D. Hannant, V.Gerber, L. Coüetil, E.A. Richard, M. Alcocer
Sci Rep (2019) 9, 15170

Donkeys are natural heat lovers

We might associate donkeys with Christmas, but new research from the University of Portsmouth shows the animals prefer hotter periods of the year.

Donkeys, it seems, love sun and warmth. That's the finding of the first study to examine the conditions under which healthy (non-working) donkeys and mules seek shelter in hot, dry climates.

It found that whilst mules would seek shelter from the heat and insects, donkeys enjoyed the sunshine and warmth for longer.

The research by equine behaviour expert Dr Leanne Proops, at the University of Portsmouth's Department of Psychology, is published in the Journal of Applied Animal Behaviour Science.
Dr Proops said: "We found that donkeys are less likely to seek shelter from the heat and light than mules. The sensitivity of mules to higher temperatures and sunlight may be due to the geographically different evolution of horses and donkeys and their adaptations to different climates. Donkeys are better adapted to arid, hot climates and hence higher sunlight levels."

"In contrast, horses are more adapted to cold conditions, and our previous research has shown that donkeys seek shelter far more often than horses in cold, wet conditions. As a hybrid, mules often display attributes that are a mixture of both species, such as their winter hair coat growth. Therefore, it might be expected that mules are less adapted to conditions of high temperatures and sunlight levels than donkeys, as we found in this study."

It is known that the effect of heat in the environment becomes physically challenging for animals once the ambient temperature surpasses their thermal neutral zone (TNZ). The TNZ is different for every species. An important method of controlling heat stress from solar radiation is for an animal to seek shade.

A total of 130 donkeys and mules were studied in two locations in Southern Spain in a seven-week period during the Summer. In both locations, researchers recorded the animals need for shade.
All the animals in the study were healthy, had free access to shelter and were regularly monitored by vets from The Donkey Sanctuary. Temperatures during the study period ranged from 14 to 37° C and data was collected between 8am and 4:15pm. For each location outside temperature, wind speed, light levels, rainfall, insect density and harassment levels were recorded.

Emily Haddy, PhD student on the project, said: "It has been very interesting to see the results from this study. Despite what equid owners may think, it is clear that different equid species have specific needs and so should be given free access to shelter - there is no 'one size fits all'."

Dr Faith Burden, Director of Research and Operational Support at The Donkey Sanctuary and co-author on the paper, points out the importance of these findings, "The majority of working equids worldwide are exposed to hot climates and as a consequence may suffer from issues such as dehydration and heat stress. By establishing the natural shelter seeking behaviour of healthy donkeys and mules across climates we hope to be able to inform welfare guidelines and encourage good management of these animals."..

Anyone with any domestic donkeys this Christmas are urged to keep them warm and dry.

For more details, see:

Shelter seeking behaviour of healthy donkeys and mules in a hot climate.
Emily Haddy, Faith Burden, Leanne Proops.
Applied Animal Behaviour Science (2019) 104898