Interviewees: Mark Chelsen, dog owner
Last summer, Mark Cheslen noticed that his dog Roxi was having trouble playing fetch at the local lake. Soon, Roxi’s vision deteriorated “to the point where she couldn’t see anything straight ahead, to the point that we’d walk out of the room and she’d still be looking up just to think we were still there,” Chelsen says.
The vet’s diagnosis: a degenerative retinal disease with no known cure.
That’s a hard answer for any pet owner to hear, and for Chelsen, more bad news was coming. Over the next few months, his nine-year old golden retriever also was found to have a brain tumor and a lung problem that eventually caused her death this past winter.
But during Roxi’s last weeks, Chelsen did have a source of comfort: Roxi could see.
Under the care of researcher and veterinary ophthalmologist Sinisa Grozdanic at Iowa State University, Roxi was the first dog to receive an experimental treatment for her retinal degeneration disease, a condition which can afflict dogs of any age. Grozdanic says after that the treatment, Roxi “pretty much recovered the vision to the point of a healthy dog”
Mark Chelsen says that as Roxi passed away, she “watched us as if to say good bye. Imagine if she could not see.”
Grozdanic cautions that Roxi’s result may not be typical. But in her case at least, the result of the eye treatment was dramatic. “If somebody told me that this is possible, a month ago, I would say that it’s just a pure lie,” says Grozdanic.
According to Grozdanic, Roxi suffered from a newly recognized disease called Immune Mediated Retinopathy, or IMR. As Grozdanic and colleagues wrote in the journal “Veterinary Clinics of North America: Small Animal Practice,” they recently discovered the cause of this disease, and a similar condition called Sudden Acquired Retinal Degeneration Syndrome, or SARDS. IMR and SARDS are autoimmune diseases in which the body produces antibodies that attack retinal tissue.
Grozdanic says dogs with IMR or SARDS lose their vision suddenly. “You have a dog which is perfectly normal, visual, happy, catching Frisbees on a nice afternoon. And the next morning you have a completely blind dog which is bumping into everything in the house” he says. “You really do not have any advanced warning signs.”
From Blind to Seeing in One Shot?
IMR and SARDS are not the only causes of sudden blindness in dogs, but dogs that do have these diseases now have cause for hope. Whereas in the past, veterinarians had no treatments or explanations to offer such patients, Grozdanic now knows what’s causing the loss of vision, and he’s had some success by treating patients with steroids or a human protein called immunoglobulin. These drugs can suppress the autoimmune attack, but when delivered to the whole body, they can cause side effects such as liver damage.
With Roxi, Grozdanic tried something new: injecting a combination of immunoglobulin and steroids directly into Roxi’s worse eye. This direct delivery prevents the drugs from damaging other organs, and with Roxi at least, Grozdanic says “she really responded excellently.”
Roxi regained vision in the treated eye, and Grozdanic and Chelsen had discussed treating her other eye. But at the same time, Roxi’s breathing was also getting worse, and she did not have long to live.
In her last weeks, with her eyesight back, Roxi was able to enjoy some of her old habits. Shortly before Roxi’s death, Chelsen said, “The other day she went and chased a squirrel, and she hasn’t done that forever.”
Grozdanic was able to determine the cause of SARDS and IMR by analyzing donated canine eye tissue, and that information helped him determine what treatments to try. The donated tissue came from a dog who, during his life, also suddenly went blind. Chelsen says the generosity of that pet’s owner motivated him to have Roxi undergo the experimental treatment. “We’ve got a lot of eyesight because of that woman,” he says. “Why not carry this on?”
In dogs who received steroids or immunoglobulin by the old method, the treatments delivered all over the body rather than just in the eye, results were less dramatic. Still, for dogs, whose other senses help them cope, Grozdanic says even modest recovery of retinal activity is a great help. “I mean, there is no vision at all, and even if we get five percent, for a dog, that can mean a lot in terms of improving quality of life, and that’s our goal. Everything that we get above that basic five percent is great,” he says.
Although both blindness diseases, SARDS and IMR, are characterized by sudden blindness, they differ in their mechanism. In SARDS patients, antibodies are produced only in the eyes, while in IMR patients, they’re produced throughout the body. In the past, SARDS was recognized but the cause was unknown. Now that Grozdanic has published his discovery of what’s causing SARDS and IMR, he’ll continue testing the intraocular injection that showed promise with Roxi.
Grozdanic says his work may have implications for a subset of people who lose their vision.”If intraocular application may be something which would help dogs, that may be a way to go in the humans. And avoid all possible side effects of other types of the therapies which are currently used,” says Grozdanic.
Grozdanic’s collaborator, Randy Kardon, Director of Neuro-Ophthalmology at the University of Iowa, says that in humans, blindness of autoimmune origin is often associated with cancer, a devastating combination for any patient.
“You can just imagine how bad it is for somebody to get diagnosed with cancer and then to go blind, maybe a few months after being diagnosed,” says Grozdanic. “If this approach really continues to work in a safe manner in the dogs, some of these things will easily be applied to humans. At least I believe so. And that can be a huge breakthrough for treatment of humans,” he says.
Roxi has left behind hope that loss of vision may be reversible for some. But that’s not all.
“She brought so much joy to everybody’s life,” says Chelsen, who recalls taking Roxi to visit his mother-in-law at a nursing home. “Everybody would be like, ‘Where’s Roxi?’ It’s not ‘Hi Mark’ but ‘Where’s Roxi?’” he says.
He adds, “Life was her party. It was always, ‘Thanks for coming.’”
This research by was published in Veterinary Clinics of North America: Small Animal Practice, March 2008, and funded by the Veterans Health Administration and Iowa State University. Sinisa Grozdanic, Matthew Harper, and Helga Kecova are the authors.
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