Cat owners, take note: If your pet appears to be in pain while eating, chewing or grooming and has a red, inflamed mouth, it may be suffering from a common condition called feline stomatitis.

“Chronic stomatitis is debilitating for cats,” says Serge Fuchs, a professor in the School of Veterinary Medicine's Department of Animal Biology and director of the Mari Lowe Center for Comparative Oncology Research. “If anti-inflammatory therapies don’t work, vets have to pull out all of a cat’s teeth. Those [cats] that don’t respond are usually euthanized because they’re in severe pain.”

That’s the bad news. The good news is that a recent study led by Fuchs and other Penn Vet researchers has demonstrated a new approach to reducing inflammation in cats with stomatitis—an approach that may also prove useful in treating human diseases.

The research that Fuchs and his colleagues conducted did not start out as an attempt to treat stomatitis. Instead, they were examining a molecular pathway that is activated when a virus infects cells of the body. In the process, they discovered that a class of drugs called PTP1B inhibitors that were already on the market to treat diabetes and obesity also worked to enhance the activity of interferon, a protein that plays a leading role in the immune system’s response to infection.

After a series of tests on human cells infected with hepatitis C and vesicular stomatitis showed that PTP1B inhibitors boosted the antiviral effects of interferon, the researchers decided to try the treatment in living creatures. Instead of turning to mice—they lack an element of the interferon signaling pathway that humans have—the Penn team looked to cats as ideal test subjects.

The researchers injected five cats that had been diagnosed with chronic stomatitis, which has been linked to infection with the feline calcivirus, with PTP1B inhibitors. Just two weeks later, all of the cats showed dramatically reduced signs of inflammation in their mouths.

Clearly this is a welcome development in veterinary medicine. But Fuchs says the benefits needn’t stop there.

“Our study suggests that PTP1B inhibitors could be re-profiled to treat viral infections in humans,” he notes. And because interferon is currently used to treat some cancer and multiple sclerosis patients, these drugs could offer relief for people with those diseases as well.