Pet owners may have a new reason to reach for the kibble.
Dry cat and dog food tends to be better for the environment than wet food, veterinary nutritionist Vivian Pedrinelli of the University of São Paulo in Brazil and colleagues report. Their analysis of more than 900 hundred pet diets shows that nearly 90 percent of calories in wet chow comes from animal sources. That’s roughly double the share of calories from animal ingredients in dry food.
The team factored in the cost of different pet food ingredients across several environmental measures. The findings, described November 17 in Scientific Reports, suggest that wet food production uses more land and water and emits more greenhouse gases than dry food.
Scientists already knew that meat-heavy human diets drive greenhouse gas emissions(SN: 5/5/22). But when it comes to environmental sustainability, “we shouldn’t ignore pet food,” says Peter Alexander, an economist at the University of Edinburgh who was not involved in the work.
Just how much various pet foods impact the environment isn’t clear, Alexander says. Commercial cat and canine fares aren’t typically made from prime cuts of meat. Instead, the ingredient lists often include animal byproducts — the gristle and bits people aren’t likely to eat anyway.
How to calculate the carbon cost of these leftovers is an ongoing debate, says Gregory Okin, an environmental scientist at the University of California, Los Angeles who was not involved with the study.
Some argue that the byproducts in pet food are essentially free, since they come from animals already raised for human consumption. Others note that any calories require energy and therefore incur an environmental cost. Plus, animal ingredients in pet food might not be just scraps. If they contain even a small amount of human-edible meat, that could add up to a big impact.
Knowing that there’s an environmental difference between moist morsels and crunchier cuisines could be helpful for eco-conscious pet owners, Okin says. Having that info handy at the grocery store is “super important when people are making decisions,” he adds. “There are consumers who want to pay attention.”
How you ‘parent’ your pooch has an impact on the kind of dog it grows up to be, a new study shows. An owner who’s highly responsive to a dog’s behavior and needs tends to lead to a more social, secure, and smart canine.
Parenting styles and choices are known to influence the way that children develop and grow. Researchers are now discovering more about a somewhat similar relationship between owners and their pets.
The researchers recruited 48 dog owners and their pets, asking them to complete a pet parenting style survey before participating in three behavioral tests in the lab, assessing attachments and interactions between the dogs and their humans.
“This an important finding because it suggests that dog owners who take the time to understand and meet their dog’s needs are more likely to end up with secure, resilient dogs.”
Based on the initial surveys, researchers put the dog owners into three categories, similar to categories used in human parenting research: authoritative (high expectations, high responsiveness), authoritarian (high expectations, low responsiveness), and permissive (low expectations, high responsiveness).
The three behavioral tests covered attachment (how the dog responded to its owner during close interactions), sociability (how the dog responded when a stranger and its owner traded places with one another in the testing room, and problem-solving(challenging the dog to get a treat from a puzzle with either no interaction at all or verbal encouragement and gestures from the owner).
Overall, dogs with authoritative owners had the highest rate of secure attachment and were highly social and sensitive to social context, compared to dogs with authoritarian or permissive owners. What’s more, the only dogs to solve the puzzle task came from the authoritative group.
The study matches up in some ways with previous research into parents and kids; specifically that children with authoritative parents are more likely to show secure attachment, thought to be because of the consistent, reliable support they get.
“This research shows that the pet dog-human caretaker bond may be functionally and emotionally similar to the bond between a human parent and their child,” says behavioral scientist Lauren Brubaker from Oregon State University.
The research opens up some interesting new questions – why, for example, did the dogs with permissive owners respond to the social cues of the stranger they were with but not their owner in one of the tests?
For now, though, the study is enough to show that there is some kind of relationship between the approach we take as dog owners and the way that those dogs then behave, even with numerous other factors in play.
“More research in this area is needed, especially replications with larger sample sizes and across different populations and cultures,” write the researchers in their published paper.
“However, our findings suggest that in the sampled population pre-existing dog–owner relationship quality served as a significant predictor of dog behavior across all three domains.”
Previous studies into the physiological effects that dogs have on humans often used imaging technology such as PET scans — no, not that type of pet but positron emission topography.
While imaging scans have a variety of medical uses, they do have some drawbacks in a study such as this one. They can be loud, and lengthy, and participants may need to remain still.
These are not characteristics that generally pair well with dogs, so previous studies frequently used pictures of dogs as stand-ins.
In this study, researchers opted to use functional near-infrared spectroscopy (fNIRS). Two electrodes were placed on participants’ foreheads to measure prefrontal cortex activity.
This area of the brain plays an important role in social cognitive processing.
Participants were measured first in a neutral state, facing a white wall. Then measurements were taken as contact with a dog was progressively introduced.
First, the participants could see the dog, then sit beside it, and finally pet it before returning to a neutral state. None of the participants had any dog allergies or phobias.
These measurements were taken across 6 sessions for each participant: 3 with a dog, and 3 with a plush animal. The plush held a hot water bottle within it to give it more weight and warmth.
Three actual dogs were used, all females ages 4 to 6. There was a Jack Russel, a goldendoodle, and a golden retriever.
The results showed that brain activity increased substantially through the progressive phases of the experiment and oxygenated hemoglobin remained elevated (indicating increased activity) even after the dog left.
The plush had similar effects but only at first. Researchers said that as participants returned for more sessions, the difference in brain activity between dog and plush sessions significantly increased.
This study found a novel application for fNIRS, but is it a good tool for the job?
Yes, it is, according to Dr. David A. Merrill, a psychiatrist and the director of the Pacific Neuroscience Institute’s Pacific Brain Health Center at Providence Saint John’s Health Center in California.
“fNIRS is valid. There are decades’ worth of study using the technique measuring brain activity. [It] affords a view into the brain based on blood oxygenation without the need for a big, immobile scanner,” Merrill told Healthline.
Jen Summers, PsyD, a utilization review specialist at Los Angeles-based Lightfully Behavioral Health, told Healthline she agreed the fNIRS is a valid measurement tool but noted other areas she would like to see explored in more detail.
As an example, Dr. Summers pointed out that Labradors are the most common dog breed for therapeutic visitation animals, but none were included in this study.
“The study participants were ‘healthy subjects,’ however, the study did not define ‘healthy.’ It would be curious for future research to determine if participants with known medical conditions (i.e. anemia, autoimmune diseases, or anyone with noted deficits in oxygenated hemoglobin) would have increased frontal brain activation compared to their baseline,” said Summers.
Putting these study results to work is of interest across the medical community.
Dr. Joey R. Gee, a neurologist with Providence Mission Hospital in Orange County, California, told Healthline that dog-assisted therapies are “valuable for many chronic disorders and may be employed in settings where ‘calming’ is needed, such as with children and in long-term care facilities.”
“Pets such as dogs can and should be considered as an important therapeutic option for patients of all ages going through any number of physical or mental health issues,” he said.
Experts noted that one interesting aspect of the study was the increased effect of multiple sessions with a dog.
“Exposure and experience foster familiarity. Psychology studies have consistently demonstrated how the mere exposure effect influences a familiarity preference: we prefer things we are familiar with versus those which are novel,” said Summers.
“This certainty and comfort are undoubtedly bidirectional such that not only do we respond more positively, the dog also tends to respond more positively to humans they are bonded to securely,” said Merrill.
A new lab at UBC’s Vancouver campus is looking for research participants—and not just anyone will do. The criteria? Must be furry and four-legged. Enjoy belly rubs and yummy treats? That’s a bonus, too.
The new Human-Animal Interaction Lab at UBC has officially opened and will soon be inviting pet dogs and their owners to engage in canine cognition research. Researchers are hoping to discover new knowledge that will improve animal shelter practices and companion animal welfare in shelters and homes with pets. They will also conduct studies on animal-assisted interventions using trained therapy dogs to benefit the wellbeing of dogs working in assistance roles, as well as refining methods of using therapy dogs in educational settings for the benefit of both the child and dog.
“The goal is to uncover knowledge about why dogs do the things they do and how do we determine the individual differences of specific dogs,” says Dr. Alexandra (Sasha) Protopopova, the lab’s director and an assistant professor in UBC’s Animal Welfare Program in the faculty of land and food systems.
The lab, which was renovated thanks to federal and provincial funding via the Canada Foundation for Innovation and the BC Knowledge Development Fund, has recently undergone inspections by UBC veterinarians to ensure it is safe for pups and their humans. The room is outfitted with specialized flooring for easy cleaning, high-tech 360-degree cameras, and a two-way mirror with an observation room next door where researchers can observe the dogs without being noticed.
Although the room is a laboratory, the researchers have worked to make it feel warm and inviting with the careful placement of silly artwork, faux plants (to disguise the cameras), and dog toys, so that the animals and their companions feel safe and comforted.
“The comfort of the animal is a priority,” says Dr. Protopopova, who also holds the NSERC/BC SPCA Industrial Research Chair in Animal Welfare. “Our work is completely non-invasive, and we take that very seriously. All research is made to benefit the welfare of animals and the dogs that come in.”
UBC PhD student Bailey Eagan and her dog Rupert demonstrate the new Human-Animal Interaction Lab at UBC. Credit: Lexis Ly/UBC
UBC PhD student Bailey Eagan and her dog Rupert demonstrate the new Human-Animal Interaction Lab at UBC. Credit: Lexis Ly/UBC
While there will be a variety of different studies underway in the lab, the overarching goal of the research is to understand individual differences in dog cognition, both in terms of breed differences and individual differences in dogs, says Dr. Protopopova.
“We take a behavioural angle to our research and look for differences between dogs on a small-scale level,” she explains. “For example, we will be looking at how dogs interact with the world and what kinds of differences we might observe in fundamental aspects of their learning, like speed of knowledge acquisition and how quickly or slowly the dog might engage with a new item.”
An example of a simple cognitive experiment that the lab could run involves the “touch” command, where the pup is taught to touch its nose to the palm of the owner’s hand. The researchers might then change the rules by having the dog learn to touch both palms of the owner’s hand. They would then monitor to determine how long it takes the dog to both learn the task and adapt to the new rules.
The lab will also serve a teaching purpose to help students understand how dogs learn, see the world, and navigate their environment. Ultimately, the research will also help inform behaviour rehabilitation practices for dogs and cats and help improve resources and knowledge for animal shelters to support the behavioural needs of the animals in their care.
From the moment a dog arrives at the lab for their appointment, Dr. Protopopova says they are continuously assessed to determine their willingness to take part. After consent is obtained from the dog owner, the dog must also demonstrate their active willingness to participate throughout the research process.
“It’s important for us to ask the dogs if they would like to participate in the same way we would invite children to participate in studies,” she says. “While we have consent forms for the owner, we also have assent procedures for the dog as well, just like we would have for children. The dogs are always given the opportunity to engage and re-engage in the experiment. If the dog does not want to go forward, or if we observe any stress signs, we let the owner know and immediately stop the experiment.”
Regardless of whether they finish, all pups earn a certificate for participating—complete with a photo of them wearing a doggie graduation cap and sash, if they wish.
“We like to think of it as earning their Ph-Dog,” says Dr. Protopopova with a laugh.
For more information on how to apply, please click here.
Leptospirosis, a disease that dogs can get from drinking water contaminated with Leptospira bacteria, can cause kidney failure, liver disease and severe bleeding into the lungs. Early detection of the disease is crucial and may mean the difference between life and death.
Veterinarians and researchers at the University of California, Davis, School of Veterinary Medicine have discovered a technique to predict leptospirosis in dogs through the use of artificial intelligence. After many months of testing various models, the team has developed one that outperformed traditional testing methods and provided accurate early detection of the disease. The groundbreaking discovery was published in Journal of Veterinary Diagnostic Investigation.
“Traditional testing for Leptospira lacks sensitivity early in the disease process,” said lead author Krystle Reagan, a board-certified internal medicine specialist and assistant professor focusing on infectious diseases. “Detection also can take more than two weeks because of the need to demonstrate a rise in the level of antibodies in a blood sample. Our AI model eliminates those two roadblocks to a swift and accurate diagnosis.”
The research involved historical data of patients at the UC Davis Veterinary Medical Teaching Hospital that had been tested for leptospirosis. Routinely collected blood work from these 413 dogs was used to train an AI prediction model. Over the next year, the hospital treated an additional 53 dogs with suspected leptospirosis. The model correctly identified all nine dogs that were positive for leptospirosis (100% sensitivity). The model also correctly identified approximately 90% of the 44 dogs that were ultimately leptospirosis negative.
The goal for the model is for it to become an online resource for veterinarians to enter patient data and receive a timely prediction.
“AI-based, clinical decision making is going to be the future for many aspects of veterinary medicine,” said School of Veterinary Medicine Dean Mark Stetter. “I am thrilled to see UC Davis veterinarians and scientists leading that charge. We are committed to putting resources behind AI ventures and look forward to partnering with researchers, philanthropists, and industry to advance this science.”
Detection model may help people
Leptospirosis is a life-threatening zoonotic disease, meaning it can transfer from animals to humans. As the disease is also difficult to diagnose in people, Reagan hopes the technology behind this groundbreaking detection model has translational ability into human medicine.
“My hope is this technology will be able to recognize cases of leptospirosis in near real time, giving clinicians and owners important information about the disease process and prognosis,” said Reagan. “As we move forward, we hope to apply AI methods to improve our ability to quickly diagnose other types of infections.”
Reagan’s group is actively pursuing AI for prediction of outcome for other types of infections, including a prediction model for antimicrobial resistant infections, which is a growing problem in veterinary and human medicine. Previously, the group developed an AI algorithm to predict Addison’s disease with an accuracy rate greater than 99%.
Other authors include Shaofeng Deng, Junda Sheng, Jamie Sebastian, Zhe Wang, Sara N. Huebner, Louise A. Wenke, Sarah R. Michalak and Jane E. Sykes. Funding support comes from the National Science Foundation.
Cornell researchers have provided the first documentation that dogs’ sense of smell is integrated with their vision and other unique parts of the brain, shedding new light on how dogs experience and navigate the world.
“It makes a ton of sense in dogs,” she said. “When we walk into a room, we primarily use our vision to work out where the door is, who’s in the room, where the table is. Whereas in dogs, this study shows that olfaction is really integrated with vision in terms of how they learn about their environment and orient themselves in it.”
Erica Andrews, a former analyst in Johnson’s lab, is the paper’s first author and currently works in canine aging research.
Johnson and her team performed MRI scans on 23 healthy dogs and used diffusion tensor imaging, an advanced neuroimaging technique, to locate the dog brain’s white matter pathways, the information highways of the brain. They found connections between the olfactory bulb and the limbic system and piriform lobe, where the brain processes memory and emotion, which are similar to those in humans, as well as never-documented connections to the spinal cord and the occipital lobe that are not found in humans.
“It was really consistent,” Johnson said. “And size-wise, these tracts were really dramatic compared to what is described in the human olfactory system, more like what you’d see in our visual systems.”
Tractography, a 3D-modeling process, allowed Johnson and her team to map and virtually dissect the white matter tracts. The findings in the digital images were later confirmed by a co-author and white matter expert at Johns Hopkins University.
Johnson said the research corroborates her clinical experiences with blind dogs, who function remarkably well. “They can still play fetch and navigate their surroundings much better than humans with the same condition,” Johnson said. “Knowing there’s that information freeway going between those two areas could be hugely comforting to owners of dogs with incurable eye diseases.”
Identifying new connections in the brain also opens up new lines of questioning. “To see this variation in the brain allows us to see what’s possible in the mammalian brain and to wonder – maybe we have a vestigial connection between those two areas from when we were more ape-like and scent-oriented, or maybe other species have significant variations that we haven’t explored,” Johnson said.
Johnson plans to examine the olfactory system’s structure in the brains of cats and horses, which aligns with the broader goals of her research program – to leverage the most advanced imaging techniques, used commonly in human clinical research, to better understand animal brain physiology and disease.
If you want to find a safe neighborhood to live in, choose one where the residents trust each other – and have a lot of dogs to walk.
In a study conducted in Columbus, researchers found that neighborhoods with more dogs had lower rates of homicide, robbery and, to a lesser extent, aggravated assaults compared to areas with fewer dogs, at least when residents also had high levels of trust in each other.
“People walking their dogs are essentially patrolling their neighborhoods,” Pinchak said. “They see when things are not right, and when there are suspect outsiders in the area. It can be a crime deterrent.”
Sociologists have long theorized that a combination of mutual trust and local surveillance among residents of a neighborhood can deter criminals, said study co-author Christopher Browning, a professor of sociology at Ohio State.
But there hasn’t been a good measure of how residents provide surveillance of neighborhood streets. “We thought that dog walking probably captures that pretty well, which is one reason why we decided to do this study,” Browning said.
For the study, researchers looked at crime statistics from 2014 to 2016 for 595 census block groups – the equivalent of neighborhoods – in the Columbus area.
They obtained survey data from a marketing firm that asked Columbus residents in 2013 if they had a dog in their household.
Finally, they used data from the Adolescent Health and Development in Context study (which Browning runs) to measure trust in individual neighborhoods. As part of that study, residents were asked to rate how much they agreed that “people on the streets can be trusted” in their neighborhoods.
Research has shown that trust among neighbors is an important part of deterring crime, because it suggests residents will help each other when facing a threat and have a sense of “collective efficacy” that they can have a positive impact on their area, Pinchak said.
Results of this study showed, as expected, that neighborhoods with high levels of trust had lower levels of homicide, robbery and aggravated assaults when compared to neighborhoods with low levels of trust.
But among high-trust neighborhoods, those with high concentrations of dogs showed an additional drop in crime compared to those with low concentrations of dogs.
Among the high-trust neighborhoods, neighborhoods high in dog concentration had about two-thirds the robbery rates of those low in dog concentration and about half the homicide rates, the study found.
It really has to do with the dog walking, Pinchak said.
“Trust doesn’t help neighborhoods as much if you don’t have people out there on the streets noticing what is going on. That’s what dog walking does,” Pinchak said. And that’s why dogs have a crime-fighting advantage over cats and other pets that don’t need walking.
“When people are out walking their dogs, they have conversations, they pet each other’s dogs. Sometimes they know the dog’s name and not even the owners. They learn what’s going on and can spot potential problems.”
Results showed that the trust and dog-walking combination helped reduce street crimes: those crimes like homicides and robberies that tend to occur in public locations, including streets and sidewalks.
The study found that more dogs in a neighborhood was also related to fewer property crimes, like burglaries, irrespective of how much residents trust each other, Pinchak said.
That’s because barking and visible dogs can keep criminals away from buildings where the dogs are found – and neighborhood trust and surveillance is not needed as a factor, as it is in street crimes.
The protective effect of dogs and trust was found even when a wide range of other factors related to crime was taken into account, including the proportion of young males in the neighborhood, residential instability and socioeconomic status.
Overall, the results suggest that it is beneficial to have a lot of trust in your neighbors to prevent crime – particularly if you add a lot of dogs and dog walkers.
“There has already been a lot of research that shows dogs are good for the health and well-being of their human companions,” Pinchak said.
“Our study adds another reason why dogs are good for us.”
The Human Animal Bond Research Institute (HABRI) revealed results of a new publication led by researchers at the Telethon Kids Institute and The University of Western Australia (UWA), which found a simple health intervention using text messaging may encourage children to spend more time being physically active with their family dog.
“This study shows that a simple text message reminder to play or walk with the family dog can result in increased physical activity for children and their caregivers,” said Steven Feldman, president of HABRI. “HABRI looks forward to raising awareness of the results of this publication which outline new and simple ways to encourage families to spend more quality time playing with and walking their dogs.”
The randomized controlled trial was published in the journal BMC Pediatrics.
“We found texting parents to remind them of how easy and important it is to be active with the family dog is a low-cost intervention with the potential to boost public health, which can be easily implemented across entire communities,” said Telethon Kids and UWA associate professor Hayley Christian, principal investigator on the study. “Interventions, policies and community programs should capitalize on the high level of dog ownership and incorporate dog walking or play into physical activity campaigns.”
Dr. Christian and colleagues led the Play Spaces and Environments for Children’s Physical Activity’ (PLAYCE) PAWS mHealth intervention, a randomized controlled trial conducted in Perth, Western Australia. Families of children between the ages of 5 and 10 with a family dog were placed into three experiment groups: one group of parents received regular text reminders about family play with the dog, one group received text reminders while also receiving a dog pedometer to further engage them with the dog, and the third group carried on as usual. This study was the first of its kind to utilize a mobile-based dog-facilitated strategy to increase children’s physical activity.
At baseline, approximately 60 percent of families walked their dogs more than once a week, and this increased to more than 75 percent at the 3-month follow-up. No differences were observed in dog walking or dog play at 1-month. The text-message only group were 2.6 times more likely to increase their frequency of total dog-facilitated activity at 3-months, compared to the usual care group. The combined intervention group were twice as likely to increase their frequency of total dog-facilitated physical activity compared with the usual care group at 3-months.
Similar findings were reported by a HABRI-funded study conducted by Richards et al., which found that significant increases in family dog walking in the intervention group only occurred at 6 months and were also sustained at 12 months. The positive associations with total dog-facilitated physical activity lost significance after adjusting for socio-demographic factors. Most parents found the intervention strategies acceptable, with 81 percent satisfied with the text-messaging program, and 83 percent satisfied with using the dog pedometer. Parents indicated that the text messages were good motivators to engage in more play with the dog.
Many dog lovers want to know what goes on in their furry friends’ minds. Now scientists are finally getting closer to the answer. In a new study just published in the journal of Animal Cognition, researchers from the Family Dog Project (Eötvös Loránd University University, Budapest) found out that dogs have a “multi-modal mental image” of their familiar objects. This means that, when thinking about an object, dogs imagine the object’s different sensory features. For instance, the way it looks or the way its smells.
The group of scientists assumed that the senses dogs use to identify objects, such as their toys, reflect the way the objects are represented in their minds. “If we can understand which senses dogs use while searching for a toy, this may reveal how they think about it” explains Shany Dror, one of the leading researchers of this study. “When dogs use olfaction or sight while searching for a toy, this indicates that they know how that toy smells or looks like”.
In previous studies, the researchers discovered that only a few uniquely gifted dogs can learn the names of objects. “These Gifted Word Learner dogs give us a glimpse into their minds, and we can discover what they think about when we ask them – Where is your Teddy Bear? –“ explains Dr. Andrea Sommese, the second leading researcher.
In the first experiment, they trained 3 Gifted Word Learner dogs and 10 typical family dogs (i.e., dogs that do not know the name of toys), to fetch a toy associated with a reward. During the training, dogs received treats and were praised for choosing this toy over a few distractor toys.
The researchers then observed how the dogs searched for the targeted toy, always placed among 4 others, both when the lights were on and off. All dogs successfully selected the trained toys, both in the light and in the dark. However, it took them longer to find the toys in the dark. Only the Gifted Word Learner dogs participated in the second experiment. Here, the researchers aimed to find out what these dogs think about when they hear the name of their toys. “Revealing the senses used by the dogs to search for the named toys gave us the possibility to infer what these dogs imagine when they hear, for example, Teddy Bear explains Dr. Claudia Fugazza, co-author of the study.
The Gifted dogs were successful in selecting the toys named by their owners in the light and the dark. This reveals that, when they hear the name of a toy, they recall this object’s different sensory features and they can use this “multisensory mental image” to identify it, also in the dark. “Dogs have a good sense of smell, but we found that dogs preferred to rely on vision and used their noses only a few times, and almost only when the lights were off” clarifies Prof. Adam Miklósi, head of the Department of Ethology at ELTE University and co-author of the study. “Dogs sniffed more often and for longer in the dark. They spent 90% more time sniffing when the lights were off, but this was still only 20% of the searching time”.
To conclude, the dogs’ success in finding the toys and the different senses used while searching in the light and the dark reveals that, when dogs play with a toy, even just briefly, they pay attention to its different features and register the information using multiple senses.
A protein that the body naturally produces could become an important new immunotherapy drug in the cache of cancer-fighting tools available to oncologists. UC Davis cancer researchers for both companion dogs and humans joined scientists from other institutions to study a new approach that triggers the body’s defense mechanisms, its T-cells and natural killer (NK) cells, to respond and destroy cancer.
Surgical oncologist Robert J. Canter with UC Davis Comprehensive Cancer Center and canine oncologist Robert B. Rebhun with the UC Davis School of Veterinary Medicine are corresponding authors for a study just published in the Journal for ImmunoTherapy of Cancer.
In the first-of-its-kind Phase 1 clinical trial, 21 pet dogs of various breeds that had metastatic lung disease resulting from osteosarcoma or melanoma were treated with protein interleukin-15 (IL-15). Although previously recognized for immunotherapy properties, IL-15 has undergone few human clinical trials because of toxicity risks associated with concentrated doses.
“No one previously had administered IL-15 as an inhaled treatment in dogs to deliver it directly to the site of the cancer. We came up with that idea as a means of reducing exposure to the rest of the body, in order to improve the benefit-risk ratio, to improve the immune stimulating effects, and to reduce toxicity,” Canter explained. “In this study, we used interleukin-15 to reinvigorate the immune system to make it recognize the cancer cells that had evaded the immune system and eliminate them.”
The research shows that amplified concentrations of IL-15 can stimulate immune system defenses against some types of cancers in dogs. IL-15 is one of several types of cytokines—substances that have signaling and regulating functions in immune system activity.
“As part of our comparative oncology research, we are strong advocates of clinical trials in companion dogs, especially for immunotherapy, as a way to speed bench-to-bedside translation,” said Canter, who is chief of the UC Davis Division of Surgical Oncology and co-director of the comparative oncology training program at UC Davis. “The cancers that afflict dogs, including sarcomas, brain tumors, lymphoma and melanoma, are incredibly similar to cancers that humans develop.”
UC Davis received a $2 million National Cancer Institute grant to fund the comparative oncology training program to support the next generation of oncology researchers collaborating on curing cancer in both humans and dogs. For instance, osteosarcoma and melanoma that develop elsewhere in the body commonly spread to the lung, in dogs as well as humans.
In the study, conducted between October 2018 and December 2020, the dogs inhaled a mist containing IL-15 twice daily. Doses were increased over time, to help determine not only effectiveness, but also tolerable levels and the ceilings above which toxicity would result. Dogs exhibited significant responses within 14 days after they began inhaling the IL-15 mist.
Tumors shrank dramatically in two dogs in the study, including one that went into complete remission for more than a year. Cancer that had been growing rapidly in five other dogs stabilized for several months. “Our overall response rate, the clinical benefit rate, was close to 40%,” Canter said.
For that and other reasons, additional studies are needed, noted Rebhun, a professor in the UC Davis School of Veterinary Medicine’s Department of Surgical and Radiological Sciences.
“The inhaled IL-15 responses that we’ve seen in dogs are better than prior human studies, but clinical benefit is seen in less than half of the dogs. Using IL-15 in people has led to potentially favorable immune responses but has not yielded good tumor responses. This indicates that combining IL-15 with other immunotherapies may result in additive or synergistic responses,” said Rebhun, who holds the Maxine Adler Endowed Chair in Oncology and is the associate director of the cancer program in the Center for Companion Animal Health.
In his view, the study yielded two significant findings: the therapy was well tolerated, and even a short two-week course of inhaled IL-15 could lead to sustained suppression of advanced and diffuse metastatic cancer. Both he and Canter noted that in eventual clinical application, IL-15 likely would be used not as a standalone therapy, but as a reinforcement in combination with other treatments.
“All of the canine patients in this study had advanced metastatic cancer, and the majority already had received prior chemotherapy, radiation therapy and, in some cases, immunotherapy. Studies are ongoing now to see whether we can predict which patients might respond to this therapy based on properties of the tumor or the patient’s immune status,” Rebhun said.
“This may help us identify patients that might respond to this therapy, as well as help us understand how to potentially combine other immunotherapies to improve response rates. We are grateful to the extremely dedicated clients who sought any and all possible care for their pets, elected to enroll them in this study, and even delivered the inhaled IL-15 to their dogs at home—in hopes that it could benefit their dog, other dogs, or possibly even people with advanced metastatic cancer,” Rebhun said.
Other authors of the study included UC Davis researchers Daniel York, Sylvia M. Cruz and Sean J. Judge, along with Colorado State University scientists Rachel V. Brady and Jenna H. Burton, and Louisiana State University researcher Sita S. Withers.
As part of the grant for the study, the National Institutes of Health supplied the recombinant IL-15, which it expressed from source materials. The study was supported in part by National Institutes of Health and the National Cancer Institute.