03/21/2013 5:12PM

Vets gain ground against disease suffered by Paynter and Barbaro

Shigeki Kikkawa
Paynter is back in training after recovering from colitis-related laminitis.

When laminitis contributed to Kentucky Derby winner Barbaro’s death at the University of Pennsylvania’s New Bolton Center in 2007, the dreaded disease – an often-fatal complication of catastrophic limb injury – commanded enormous public attention. So did the fundraising efforts to cure this age-old veterinary problem.

Six years later, clinicians and researchers say, the veterinary profession is gaining ground in the battle, thanks to research and improvements in areas from digital radiography to glue-on horseshoes to cryotherapy, also known as cold therapy.

Some of that promising research is taking place at the New Bolton Center, which treated the two horses whose highly publicized bouts with the painful hoof disease in recent years have had very different outcomes: Barbaro, who was euthanized after developing laminitis secondary to his breakdown, and Haskell winner Paynter, who recovered from colitis-related laminitis last year and is back in training.

“We understand the disease much better now than we did even five or 10 years ago,” said Dr. James Orsini, director of Penn’s Laminitis Institute. “A ‘shock organ’ is an organ that fails related to some sort of systemic disease. In people, the lung is one of those organs. What we’re finding is that the lamellar tissue in the horse’s foot is a similar target organ for the horse. So, we know that if we can treat these other diseases more effectively — like colitis, or a mare with a retained placenta, or a horse with pleural pneumonia — we can better protect the foot from becoming the shock organ that ultimately fails and results in a crippling disease.

“If I could identify one or two game-changers,” Orsini added, “I’d say one is our ability to look at the molecular level of the tissue, to actually look at the cells and better understand what’s occurring on a molecular level relative to the tissue inflammation and the derangement of the tissue. The other thing that’s helped is we now understand that a technique that’s been around for hundreds of years — using cold therapy — is one of the best techniques available to us. We can identify the at-risk horse better, and our goal is to prevent the disease rather than have to treat it.”

Veterinarians don’t just look to the foot when tackling laminitis. They carefully consider the underlying cause and then try to stabilize that cause, Orsini said. And today, they are applying therapies aggressively to at-risk horses, not just to those showing acute signs of laminitis, said Dr. Bryan Fraley, a farrier and veterinarian whose Fraley Equine Podiatry is affiliated with Hagyard Equine Medical Institute in Kentucky.

Fraley was one of the vets who treated Paynter. That colt underwent cryotherapy well before he showed any distress from the disease.

“It’s been proven that if we ice these horses before they ever show clinical signs, and sometimes even in the early acute stages that are initially painful, we can actually help minimize the changes,” Fraley said. “We can try to prevent those horses from going from acute to chronic.”

Paynter did develop early signs of the disease, Fraley said, prompting the team to apply casts to prevent his coffin bone from sinking if the laminitis progressed.

“In my experience, if we apply foot casts with impression material like dental impression material to the bottom of the foot, we give those horses very good support to the center of the bony column,” Fraley said. “We try to unload the wall and the laminae. In Paynter’s case, it worked.

“In the past, we were often waiting for horses to show clinical signs,” Fraley said. “Now, we’re trying to identify horses that are at risk before they ever show the first symptom.”

Dr. Hannah Galantino-Homer at Penn’s Laminitis Institute hopes her research into “serum biomarkers” — molecular changes in the blood that can signal laminitis-induced tissue changes — someday will help clinicians identify signs of laminitis even faster.

“Our overall goal is to find diagnostic markers, like serum tests, that would allow us to detect [laminitis signs] early and to give us some sense of how they’re going to do — a prognosis,” Galantino-Homer said. “One marker we’re looking at, we have a horse who was euthanized for supporting-limb laminitis with complete detachment of the hoof capsule, and it looks like that marker went up pretty early. So, if we have a large-enough study with a lot of horses, collecting from the clinic and following through to see what happens, we might be able to correlate that marker with how much damage they have.

“Because that damage doesn’t always show up until much later,” she added. “People talk about taking X-rays and looking at whether the coffin bone has moved relative to the hoof capsule. But that happens after the damage occurs. If we can detect the damage earlier, that would be helpful in those intensively managed hospital cases.”

Galantino-Homer’s lab also is helping to develop a database of naturally occurring laminitis cases and a tissue bank showing changes at various stages of the disease. Her team is working to develop a laboratory in-vitro system so they can study the lamellae cells more closely and easily. They are discovering some interesting angles on this ancient disease.

“The pathologist I work with, Julie Engiles, has been looking at the bone changes and how that’s not just a consequence of laminitis,” she said. “That’s happening very early and could be propagating the disease and be a big source of the pain.”

Another key is to prevent or quickly resolve the issues that lead to laminitis, including catastrophic breakdowns. As in Barbaro’s case, a horse who undergoes surgery to repair one leg is at risk of developing support-limb laminitis, caused by overloading a sound limb as the horse shifts weight from an injured one.

“It’s important to think about any pre-existing bone disease, too, and to ask if we can make bone heal faster,” said Dr. Kurt Hankenson, who holds the Dean W. Richardson Chair for Equine Disease Research at Penn.

Among the practical laminitis-prevention developments to help the post-surgical horse, according to Hankenson: “Mats in stalls, which are being used with greater frequency to provide some cushion.”

Hankenson noted that improvements in shoeing technologies, such as glue-on shoes, can aid support for injured horses and potentially reduce the laminitis risk.

Laminitis research has benefited from high-profile cases like Barbaro and Paynter. After Barbaro’s death in 2007, Gretchen and Roy Jackson, Barbaro’s owners and breeders, donated $3 million to endow the Dean W. Richardson Chair that Hankenson now holds. Later that year, philanthropists Marianne and John Castle gave Penn’s vet school $1 million for laminitis research.

This month, the Grayson-Jockey Club Equine Research Foundation included a pair of laminitis-related projects in its 2013 funding grants. And the American Association of Equine Practitioners Foundation also has laminitis studies underway and planned for the future.

But researchers note that the overall funding for laminitis study remains relatively small. More funding would enhance research, but in the meantime, the small community of laminitis researchers has come up with some useful collaborations, Orsini and Galantino-Homer said.

Clinicians also are collaborating. Paynter was a case in point. Veterinarians from New York’s Upstate Equine Medical Center, Penn’s New Bolton Center, and Kentucky’s Hagyard clinic were sought out by owner Ahmed Zayat for advice in solving both colitis and secondary laminitis. Even on a smaller scale, horsemen can expect a team approach when it comes to laminitis treatments, including the veterinarian or surgeon treating the initial injury or sickness, as well as the farrier.

“We have a lot better technologies in terms of the types of glue-ons and shoes that are out there,” Fraley said. “We have options, from new polyurethane shoes to better support materials. I think farriers are critically important in the treatment of a laminitic horse. Farriers are usually first on the scene and first to recognize the problem. They often recognize subtle changes, and in acute cases, they can get shoes off quickly, with minimal trauma, and help veterinarians get that horse better foot support.”

Fraley and others caution that the difference in Paynter’s outcome versus Barbaro’s is due to a number of factors, including the different causes that led to each horse’s laminitis. That’s an important distinction for veterinarians because different causes might call for slightly different treatments.

“And I think we’re better today at deciphering the different causes,” Orsini said.

Orsini noted improvements in equine medications for some of the specific conditions that can lead to laminitis, like Cushing’s disease, and there is ongoing research into the safest and most effective pain medications.

“The older nonsteroidals like ibuprofen that we take as two-legged patients, there are now drugs that are very specifically formulated for the horse that are even better anti-inflammatories with fewer side effects,” Orsini said.

Dr. David Hood of the Hoof Project Foundation in Texas is working with researchers at the University of California-Davis to study the effectiveness of pain medications. And while clinicians often are focused on preventing or halting very early-stage laminitis, Hood also is looking at laminitis from the other end of the timescale, seeking solutions on how to best rehabilitate horses who have chronic laminitis.

One of the advances in that area is Hood’s own development, a force-plate system similar to an electronic scale that allows him to measure more precisely how much weight a laminitic horse is putting on each limb at any given time.

“We can see exactly how lame the horse is, which foot is worse,” Hood said. “We’ll usually then do a diagnostic nerve-blocking workup on them using the force-plate to see where the pain is coming from.

“We’re also doing some laminar biopsies now, looking at the type of healing that’s going on inside the foot,” he added. “We’ll go in through the dorsal wall and take a little piece of tissue and work on it, look at it with a microscope.”

More research at the molecular level should mean that more knowledge and better treatments – possibly including stem-cell therapy – are on the way, clinicians and research vets said.

“We haven’t eliminated all cases of kidney, lung, or heart failure in people,” Penn’s Galantino-Homer pointed out, noting that laminitis will likely always be with horses. “But we’re going to make it less common, we hope, and more treatable.”