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November 2022
Notebook: November 2022
Veterinary news briefs from across the industry and beyond. This month’s articles include: Dogs Tear Up With Emotion; Progress Toward a Stem Cell–Based Therapy for Blindness; Diabetes in Dogs Associated with Seasons; and more!
Progress Toward a Stem Cell–Based Therapy for Blindness
Following a transplantation procedure, human photoreceptor precursor cells labeled red migrated and integrated into a degenerated canine retina. The green label is a synaptic maker, suggesting the transplanted cells began forming a connection with second-order neurons in the retina.
A multi-institutional effort is taking steps to develop a technique to regenerate photoreceptor cells and restore sight in people with vision disorders. The work, led by a team at the University of Pennsylvania School of Veterinary Medicine, in collaboration with researchers at the University of Wisconsin-Madison, Children’s Hospital of Philadelphia, and the National Institutes of Health’s National Eye Institute, introduced precursors of human photoreceptor cells into the retinas of dogs. A cocktail of immunosuppressive drugs enabled the cells to survive in the recipients’ retinas for months, where they began forming connections with existing retinal cells. The study is published in the journal Stem Cell Reports.
“In this study, we wanted to know if we could, one, improve the surgical delivery of these cells to the subretinal space; two, image the cells in vivo; three, improve their survival; and four, see them migrate to the layer of the retina where they should be and start integrating,” says William Beltran, a professor of ophthalmology at Penn Vet and senior author on the study. “The answer to all those questions was yes.”
UC Davis Launches Clinical Trials to Treat Coronavirus Disease in Cats
Scientists from the University of California-Davis School of Veterinary Medicine have launched clinical trials focused on improving treatments for feline infectious peritonitis, or FIP, and are currently enrolling patients at the UC Davis veterinary hospital.
One trial will compare whether cats improve when treated with one of two closely related antiviral drugs. The first drug, remdesivir, is an antiviral drug with emergency use authorization from the Food and Drug Administration to treat COVID-19. If fully licensed, veterinarians could prescribe it to affected cats in the future. The second drug, GS-441524, is closely related to remdesivir.
The other trial, funded by the National Institute of Child Health and Development, will examine if antiviral drugs combined with a new stem cell therapy using mesenchymal stem cells, or MSCs, improve response to treatment for FIP.
The school reports that the trial could help humans as well. It is part of a larger study looking into new treatments for multisystem inflammatory syndrome in children, or MIS-C, a condition that causes organs and other body parts to become inflamed.
QUOTE OF THE MONTH
“Far and away the best prize that life offers is the chance to work hard at work worth doing.”
—Theodore Roosevelt
Dogs’ Eyes Tear Up When Reunited with Owners
Research from Takefumi Kikusui, PhD, a professor at the Laboratory of Human-Animal Interaction and Reciprocity at Azabu University in Japan, suggests that a dog’s eyes may well up with tears of happiness when reunited with their owner after a period of absence.
Kikusui reports that he decided to investigate dog tears after watching one of his two standard poodles when she had puppies six years ago. He noticed that her eyes got teary as she nursed her puppies. “We found that dogs shed tears associated with positive emotions,” Kikusui, who coauthored the research that was published in the journal Current Biology, said in a news release. He relates that the team made the discovery of oxytocin as a possible mechanism underlying it, referring to the hormone that in humans is sometimes called the love or maternal hormone.
Researchers stated that there is much they still don’t know about dog tears, including whether they cry in response to negative emotions as humans do, or if a dog’s ability to tear up plays a social function in the canine world. Kikusui said it was possible humans would better care for dogs that got teary-eyed. His team showed 74 people pictures of dogs’ faces with and without artificial tears in them and asked them to rank the animals. People gave more positive responses when they saw dogs with teary eyes.
Diabetes in Dogs Associated with Season, Region
Research published in the journal PLOS ONE looked at 960 pet dogs with diabetes mellitus living across the United States. Researchers from the University of Pennsylvania School of Veterinary Medicine found that diabetes diagnoses were significantly more likely to occur in the winter and in the northern US compared with any other season or region. They report that although the findings don’t explain the underlying cause of this correlation, the link with cold weather hints at future possibilities to pursue.
Hypotheses about the connection between colder and more northerly climates and diabetes diagnoses in humans include links to vitamin D deficiency, diet, lifestyle, and viral infections. In dogs, the diet connection seems unlikely, says Rebecka Hess, BSc, DVM, DACVIM, a professor at Penn Vet and senior author on the study, as most dog owners feed their pets a commercially available kibble, no matter their location or the season. In addition, she says, overweight and obese dogs aren’t at higher risk of developing diabetes, so a connection with exercise, or lack thereof, seems unlikely.
Study Validates CBTC Criteria for Diagnosing Canine Glioma
A multi-institutional team led by North Carolina State University reports that researchers found that using recently released criteria for the diagnosis of canine glioma resulted in strong diagnostic consensus among pathologists. Researchers report that the findings not only pave the way for more standardized diagnostic criteria for dogs with brain tumors but also create a useful baseline to support larger interinstitutional studies that could aid dogs and humans with glioma.
“The CBTC (Comparative Brain Tumor Consortium) system of diagnostic criteria could be very useful not only in the clinical diagnosis of canine patients but also in enabling interinstitutional research collaboration, since it has everyone speaking the same language, diagnostically speaking,” says Gregory Krane, DVM, PhD, DACVP, colead author of the paper. “To that end, we wanted to conduct a real-world assessment of the system.”
Krane obtained 85 glioma samples taken from dogs examined at NC State between 2006 and 2018. Five pathologists—one human-medicine neuropathologist, two veterinary neuropathologists, and two veterinary pathologists without subspecialty training in neuropathology—separately examined the samples using the CBTC guidelines.
“The study also shows that even with detailed diagnostic criteria, pathologist consensus is often not 100%. For a clinical setting, practitioners should be comfortable talking with their pathologist if the diagnosis is not compatible with the rest of the clinical picture, and in the research setting, investigators can strengthen their studies by incorporating groups of pathologists into the diagnostic review,” researchers say. The study appears in Veterinary and Comparative Oncology.
Senate Passes Bipartisan Bill to Protect Pets and Other Animals During and After Natural Disasters
Coast Guard Shallow-Water Response Team 3 crewmembers rescue pets from rising flood waters caused by Hurricane Florence in North Carolina on Sept. 18, 2018.
Bipartisan legislation to help protect pets and other animals during and in the aftermath of natural disasters and emergencies has passed the Senate. The Planning for Animal Wellness (PAW) Act directs the Administrator of the Federal Emergency Management Agency (FEMA) to establish an advisory group with outside experts that will align FEMA guidance to match current best practices in animal care for disaster preparedness, response, and recovery. The bill now moves to the United States House of Representatives for consideration.
The PAW Act would require the FEMA Administrator to establish an advisory group to encourage and foster collaborative efforts among individuals and entities working to address the needs of animals in disaster preparedness. The working group will review current best practices and federal guidance on sheltering and evacuation planning for household pets, service and assistance animals, and other animals, as appropriate. If the Administrator, in consultation with the working group, finds that current federal guidance does not meet best practices, FEMA is required to publish updated guidance in consultation with the advisory group.
Different Levels of Dog-Owner Bond Are Reflected in Dogs’ Sleeps
Researchers of the Department of Ethology at Eötvös Loránd University, Hungary, report that they have provided the first evidence that the sleep pattern of dogs who slept in a new place with their owner was influenced by the dog-owner attachment bond.
The dog-owner attachment bond has already been studied in a number of behavioral tests; this time the researchers wanted to know whether in dogs, similarly to children, attachment has an effect on the quality of sleep in a new environment.
The attachment bond of 42 dogs to their owners was measured using the adapted version of the Strange Situation Test, developed by psychologists to assess human infant-mother bond.
Researchers found higher attachment scores to be associated with spending more time in deep sleep, known as the most relaxing sleep phase.
“Sleeping in a new place for the first time can be stressful. But these results suggest that dogs with higher attachment scores sleep better, presumably because the owner of these dogs provides a more secure environment for their dog; thus, they can relax and have a good nap,” says the first author Cecília Carreiro, PhD. The study was published in the journal Animals.
Catnip Repels Mosquitos
A research group at Iwate University, Nagoya University, Kyoto University, and University of Liverpool conducted research on catnip and silver vine, which have been known as cat attractant plants. They report that their research, published in the journal iScience, found that the behavior had more practical reasons than creating a feeling of euphoria.
“The first appearance of silver vine (Matatabi in Japanese) as a cat attractant in literature in Japan dates back to more than 300 years ago. A folklore Ukiyo-e (a genre of Japanese woodblock prints and paintings) drawn in 1859 shows a group of mice trying to tempt some cats with a smell of silver vine. Still, benefits of the cats’ response had remained unknown,” says Masao Miyazaki, PhD, of Iwate University, a leader of the research project.
The research group first identified the active ingredient of silver vine that induces the response. They isolated substances from extract of silver vine leaves and administrated each of them to cats to examine the response. The experiment revealed that nepetalactol, a novel substance, most strongly induces the characteristic behavior. The research group believed that the plant has another biologically important function as the reaction was already shown in feline animals when they evolved from other species about 10 million years ago. On the basis of some reports that nepetalactone has mosquito repellent activity, researchers tested the mosquito repellent property of nepetalactol on cats. They found that the cats’ reaction to silver vine is chemical defense against mosquitoes, and perhaps against viruses and parasitic insects.
CSU Trial Studies Canine and Human Dementia
Stephanie McGrath, DVM, (right) and Breonna Thomas (left) work with a golden retriever for a clinical trial at the James L. Voss Veterinary
Teaching Hospital.
A new study is underway at the Colorado State University James L. Voss Veterinary Teaching Hospital to understand the response to three different medications in the treatment of canine cognitive dysfunction syndrome (CCDS) in aging dogs, with the long-term hope of advancing Alzheimer disease treatments in humans. The study, “Investigating the effect of trazodone, rapamycin, and cannabidiol on cognitive dysfunction in dogs,” is led by principal investigators Stephanie McGrath, DVM, and Julie Moreno, PhD, and the researchers are looking for people who would like to have their dogs evaluated for enrollment in the study.
The researchers state that dementia is a problem for aging humans and dogs alike. As the proportion of older Americans relative to the overall population in the US continues to rise, Alzheimer disease and other forms of dementia are becoming increasingly frequent causes of disability and death. The likelihood of Alzheimer disease increases with age, affecting 5.3% of people between the ages of 65 and 74, rising to 13.8% in 75- to 84-year-olds, and ballooning to 34.6% for those over the age of 85. What’s more, the number of Americans over age 65 is projected to increase from 58 million in 2021 to 88 million by 2050.
One of the challenges to discovering a treatment for Alzheimer disease is identifying a good model for research, which is where canine cognitive dysfunction syndrome comes in. CCDS is a neurodegenerative disease affecting dogs with many similarities to Alzheimer disease. It affects 14–35% of dogs over the age of eight, and that percentage continues to increase with advancing age, with one study reporting that 68% of dogs 15 to 16 years old are affected. Signs of CCDS include changes in behavior, like disorientation, irritability, changes in sleep cycles, house soiling, and decreased activity.
According to researchers, the disease also has a great deal in common with Alzheimer disease in humans, even at the biological level. The brains of patients with Alzheimer disease classically have deposits of beta-amyloid protein known as plaques, and neurofibrillary tangles marked by hyperphosphorylated tau proteins, observations also made in dogs with CCDS. Dogs typically share a home closely with their humans and are subject to many of the same environmental exposures.
“The discovery of therapeutics for diseases like Alzheimer disease is essential but extremely difficult as we are unable to fully model it appropriately in the basic research laboratory,” Moreno, an assistant professor in the Department of Environmental and Radiological Health Sciences, said. “However, when collaborations like ours exist, we can take findings from a mouse or a worm and apply them to a dog with clinical disease. The advantage of dogs is that they have a naturally occurring form of Alzheimer disease that is similar to the human form.”
Photo credits: Photo courtesy of the Beltran laboratory/Stem Cell Reports, siridhata/iStock via Getty Images Plus; Nataba/iStock via Getty Images Plus, Imgorthand/E+ via Getty Images; Goodboy Picture Company/E+ via Getty Images , Photo Courtesy of Iwate University; Photo courtesy of Colorado State University