Dogs and humans could benefit from potential new therapies and diagnostic techniques for a degenerative neurological disease
By Kim Campbell Thornton
Andrews McMeel Syndication
New therapies and diagnostic tests have the potential to help dogs with a progressive neurodegenerative disease live longer lives. Boxers, German shepherds and Pembroke Welsh corgis are among more than 100 breeds and mixes that may benefit from two therapies being studied, as well as a diagnostic biomarker test for degenerative myelopathy, a disease of the central nervous system that develops late in life.
The condition, which typically affects dogs between 8 and 14 years old, damages the spinal cord, muscles, nerves and brain, causing loss of muscle control, weakness in the hind legs and, eventually, paralysis. Dogs with two copies of a mutation in the gene superoxide dismutase 1 (SOD1) are at risk for the disease, but not all dogs with the mutation will develop the disease.
Early signs include dragging or shuffling the hind legs. At first, owners may suspect the weakness or lameness is caused by an orthopedic condition or simply advancing age, says Dominik Faissler, DVM, assistant professor of neurology at Tufts Cummings School of Veterinary Medicine in North Grafton, Massachusetts.
As the disease progresses, the dog may stumble and fall, have difficulty standing up and lose mobility as the nervous system becomes unable to transmit motor commands between brain and limbs. Gradually, the brain stem becomes affected, causing difficulty swallowing. Paralysis usually occurs in the space of a year. Most dogs are euthanized before they develop difficulty breathing, Dr. Faissler says.
Currently, a DNA test developed in 2009 is available to identify the recessive gene mutation that causes the disease, allowing breeders to avoid producing affected dogs, but last year’s discovery of a diagnostic biomarker can help lead to earlier diagnosis of dogs at risk of developing DM, as it’s called for short. It’s also important for researchers in human medicine who study amyotrophic lateral sclerosis (ALS), better known as Lou Gehrig’s disease. The same mutation that causes DM in dogs also causes ALS in humans.
Finding the biomarker involves collecting cerebrospinal fluid from the affected dog. That’s more difficult and expensive than a blood test because it requires anesthesia, but less expensive than magnetic resonance imaging (MRI). Because DM mimics other diseases such as intervertebral disc disease and spinal cancer, an MRI is part of the process to rule out those conditions. Even then, the diagnosis is not considered definitive until the dog dies and a necropsy is performed. As the biomarker test becomes more widely available, it may help to provide earlier and more reliable diagnoses. And earlier diagnosis goes hand in paw with the search for effective therapies.
One of the therapies being studied involves injecting antisense oligonucleotides (ASOs) into the spinal fluid with the goal of suppressing production of the mutant protein SOD1. Researchers hope the molecular therapy will be able to sneak past the blood-brain barrier and “silence” the messenger RNA, slowing or stopping disease progression. Affected dogs who meet certain criteria may be eligible to participate in the study, conducted at the University of Missouri. A gene-silencing study is also under way at Tufts Cummings School.
A gene therapy clinical trial, also at the University of Missouri, injects what’s called interference RNA (iRNA) into the spinal fluid to repress production of the SOD1 protein. Dogs in the early stages of the disease may also be eligible to participate in that study.
Both University of Missouri studies are randomized and double-blinded. That means neither researchers nor owners know which dogs receive the treatment and which receive a placebo. The study’s design gives dogs a 67 percent chance of receiving the treatment, according to the university’s website.
The treatments have been tested for safety, but their effectiveness isn’t yet known. The same therapeutic approach is being studied in humans with SOD1-associated ALS. Success in either dogs or humans will likely benefit both.
How to find a
Q: We have moved cross-country and need to find a veterinarian for our two cats. Do you have any tips for us?
A: I like your priorities. Finding a great veterinarian should be at the top of the to-do list for any pet person who’s new in town.
You can use a number of filters to narrow the search for your cats’ veterinarian. The one that’s nearest and dearest to my heart is Fear Free certification. Veterinarians with Fear Free credentials know how to approach and interact with cats in a manner that caters to their needs for security, gentle handling and a calm environment. Practice visits, treats and pheromones are among the techniques used to give cats a fabulous experience they won’t mind repeating throughout life.
I also asked a couple of my cat-expert colleagues to weigh in with their advice. Jane Brunt, DVM, executive director of the CATalyst Council and past president of the American Association of Feline Practitioners, suggests searching online for veterinarians in your own zip code so your cat doesn’t have to travel far to get to the clinic. She also suggests looking for a Cat Friendly Practice designation accreditation by the American Animal Hospital Association. Ask pet-owning family or friends for recommendations. Call a practice to make an appointment for a tour. How the receptionist handles your call is a good clue as to how well the practice is run.
Winn Feline Foundation Executive Director Vicki Thayer, DVM, a specialist in feline veterinary care, says veterinarians and staff should exhibit a love and understanding of cats in the way the waiting room and exam rooms are set up with cat behavior in mind. They should handle cats calmly, slowly and quietly and offer helpful advice on getting the cat to -- and into -- the hospital with minimal anxiety. -- Dr. Marty Becker
Do you have a pet question? Send it to firstname.lastname@example.org or visit Facebook.com/DrMartyBecker.
App updates owners
about pet condition
-- Want to know how your hospitalized pet is doing? There’s an app for that. Texas A&M Veterinary Teaching Hospital in College Station has begun using an app called EASE (Electronic Access to Surgical Events) that allows veterinarians to give pet owners real-time updates on a pet’s status using videos, texts and photos. The app originated for use in human hospitals to allow doctors to send HIPAA-compliant messages to family members. Texas A&M is the first veterinary teaching hospital to adopt it. The app is a way to help support owners emotionally, says oncology technician supervisor Jaci Christensen.
-- A biobank of dog tumors hopes the donated tissue will help lead to new models and treatments for cancer in dogs and humans. Owners of dogs diagnosed with a cancer of interest at veterinary hospitals in partnership with Tallwood Canine Cancer Research Initiative by Jackson Laboratory can ask the veterinarian to donate their pets’ tumors after removal. The tumors will be used to create cancer models. Researchers will also sequence DNA from healthy dogs of specific breeds and compare it to dogs of the same breed who have cancer.
-- As pets live longer, helping them maintain quality of life and mobility is an important facet of veterinary medicine. Your veterinarian may be helping you manage your pet for cognitive dysfunction, chronic high blood pressure, kidney disease, Cushing’s disease and diabetes, to name just a few. For your golden oldie, consider a diet rich in omega-3 fatty acids and other antioxidants, which have been shown to enhance brain health. You can also keep the brain sharp with gentle play and exercise. Medication can help with hypertension, cognitive dysfunction, arthritis, diabetes and other conditions. Easy but important: Maintain a routine and be alert to subtle behavior changes that may indicate health problems. -- Dr. Marty Becker, Kim Campbell Thornton and Mikkel Becker
ABOUT PET CONNECTION
Pet Connection is produced by a team of pet-care experts headed by "The Dr. Oz Show" veterinarian Dr. Marty Becker and award-winning journalist Kim Campbell Thornton. They are affiliated with Vetstreet.com and are the authors of many best-selling pet-care books. Joining them is dog trainer and behavior consultant Mikkel Becker. Dr. Becker can be found at Facebook.com/DrMartyBecker or on Twitter at DrMartyBecker. Kim Campbell Thornton is at Facebook.com/KimCampbellThornton and on Twitter at kkcthornton. Mikkel Becker is at Facebook.com/MikkelBecker and on Twitter at MikkelBecker.