Our gastrointestinal tracts have a huge community of microbes living there, some are good and some can be harmful. These microorganisms may play a role in the development of diseases including inflammatory bowel disease (IBD). Knowing that some dogs suffer from IBD, researchers at the University of California San Diego School of Medicine decided to analyze fecal samples from dogs that both had and did not have the disease. They found there was a pattern of microbes that indicated IBD in dogs. Using their data, published
in Nature Microbiology, the scientists diagnosed IBD in dogs with greater than 90 percent accuracy. Unfortunately, they also learned that because the gut microbiomes of humans do not share enough similarities with those of dogs to use the pups as a model for the disease.
“One of the really frustrating things about IBD in humans is that it’s hard to diagnose — it usually requires intestinal biopsies, which are not only imperfect, but invasive and expensive to collect,” explained the senior author of the research, Rob Knight, a Professor in the Departments of Pediatrics at UC San Diego School of Medicine and Computer Science and Engineering as well as the Director of the Center for Microbiome Innovation at UC San Diego.
Knight said that there are changes in the gut microbiomes of people that have IBD, similar to what was seen in dogs. But just looking at the gut microbiomes of people is not enough to determine which people are healthy and which are not. Additionally, Knight explained that it is not yet understood whether such patterns are the cause or the result of the disorder.
Using fecal samples from 85 healthy dogs and 65 dogs showing chronic symptoms of gastrointestinal distress and pathology confirmation of inflammatory changes. They assayed for the microbes present in each sample using 16S rRNA sequencing, the typical way to identify the microbial residents of a community. To learn more about how 16S RNA sequencing is used in microbiome studies, watch the lecture below from Dr. Christopher Taylor, an Assistant Professor in the Department of Computer Science at the University of New Orleans. Back to the current study, the team found that differences between healthy and unhealthy dogs allowed to then identify whether the feces came from a dog with or without IBD with over 90 percent accuracy.
The researchers have made their findings easy to dissect for those that are interested as well. “One of the really nice things about this study is that all of the statistical software packages we used to analyze data are available online, and anyone can see our exact calculations,” said Yoshiki Vázquez-Baeza, a a member of Knight’s lab and a graduate student at the UC San Diego Jacobs School of Engineering’s Department of Computer Science and Engineering. “Too often we read about a study with interesting conclusions, but it’s not completely clear how the authors got there. This approach is more open and transparent.”
This approach is not yet available for use by vets in the clinic, however. The work may be used for such a diagnostic test, but for now the researchers are looking at the shifts in the microbiomes of other animals with and without IBD. For example, zoo animals suffer from IBD more often than their counterparts in the wild, and studying them could help find out if there are microbes that play key roles in IBD across species.
Previous work by Knight’s team also found that the microbial communities of human adult skin have more in common with their own dogs than with random dogs, which suggests that pets can aid in microbe sharing among residents of a home. The researchers can pick out what dogs belong to which humans just based on microbiome overlap, with a fair degree of precision.
If you’d like to know more about IBD, watch the video above.
, Nature Microbiology