S100A12 Protein as a Marker of GI Health in Dogs

The protein S100A12 has recently been investigated for its cytokine-like effects and is believed to play a role in immune function. Studies indicate S100A12 is a useful biomarker of localized inflammation in humans, as patients with inflammatory bowel disease often have increased fecal concentrations of the protein.

Because rodent species do not express S100A12, researchers in Germany and Texas recently proposed the use of S100A12 as a marker of gastrointestinal (GI) disease in the dog, with hopes that the species may serve as a model for human research. They examined fecal S100A12 protein concentrations in dogs infected with a variety of enteric parasites and viruses, and their findings were recently published in Parasites & Vectors.

Study Design

The study included apparently healthy, purebred puppies from French breeding kennels that were categorized as small breed (≤25 kg) or large breed (>25 kg).

A voided fecal sample and a rectal swab for virology were collected from each puppy. Fecal consistency was ranked from 1 to 13, with low scores considered abnormal.

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The investigators screened fecal samples for major diarrheal diseases, including Toxocara canis, Cystoisospora spp, Giardia spp (using both McMaster flotation and ELISA), canine coronavirus (CCV), and canine parvovirus (CPV). At the Gastrointestinal Laboratory at Texas A&M University, a previously validated I-radioimmunoassay was used to quantify fecal S100A12 concentrations in batched samples.

The authors then performed both univariate and multivariate analyses to examine associations among dog size (large vs small breed), presence of infectious diseases, fecal consistency score, and fecal S100A12 concentration.

Results

The study included samples from 307 puppies with a median age of 7 weeks (range, 4-13 weeks) representing 29 breeds. Most dogs (75%) were classified as large breed, and the most commonly represented breeds were Labrador retrievers (57 puppies) and German shepherds (41 puppies).

The median fecal consistency score was 8 (range, 1-12), indicating that most samples were normal. Depending on species, GI parasite prevalence ranged from 21 to 41%, while 20% and 18% of dogs tested positive for CCV and CPV, respectively.

The median fecal S100A12 concentration was 24 ng/g (range, <24-14,363 ng/g), and 6% of dogs had concentrations above the 745 ng/g reference interval upper limit. Univariate analysis revealed that fecal S100A12 concentrations were higher in dogs infected with Cystoisospora, CCV, and CPV compared with uninfected dogs; however, these effects became insignificant on multivariate analysis and thus were not influential.

Univariate and multivariate analyses confirmed that small-breed puppies and those with abnormal fecal consistency scores had significantly higher fecal S100A12 concentrations than other puppies.

Take-home Message

Infection with the studied enteropathogens did not significantly increase fecal S100A12 concentrations. However, dogs with abnormal fecal consistency generally had higher S100A12 concentrations than those with normal feces, suggesting that the dog may be an appropriate model to study the role of S100A12 in human GI disease.

Dr. Stilwell received her DVM from Auburn University, followed by an MS in Fisheries and Aquatic Sciences and a PhD in Veterinary Medical Sciences from the University of Florida. She provides freelance medical writing and aquatic veterinary consulting services through her business, Seastar Communications and Consulting.