Researchers at North Carolina State University announced on Mar. 30 that they have identified a molecule, artemin, as a possible marker and therapeutic target for cats with degenerative joint disease (DJD), the main form of which is osteoarthritis. The study provides new evidence that naturally occurring osteoarthritis in cats shares important biological features with human disease.
Understanding how pain is generated in cats with DJD has been challenging due to limited research and few effective treatments. The researchers compared known pain pathways active in humans and dogs to those in cats, focusing on transient receptor potential (TRP) ion channels found in the spinal cord’s dorsal root ganglia (DRG). These channels can be activated by artemin binding to its receptor GFRA-3, triggering signals associated with pain.
“We know that Artemin/GFRA-3 induced changes to TRP channels play a role in osteoarthritis pain in humans and dogs, but didn’t know whether cats shared this biological pathway,” said Santosh Mishra, associate professor of neurobiology at North Carolina State University and co-corresponding author of the study.
The team conducted detailed assessments on more than 70 cats to compare healthy animals with those affected by DJD. They examined blood serum and DRG tissue samples from both groups. Their results showed that TRP channels linked to osteoarthritis pain are present and functional in healthy cat neurons. In addition, increased artemin concentrations were observed in the blood of cats diagnosed with DJD through X-rays but did not always correspond with veterinarian-assessed pain levels.
“These results are interesting for a couple of reasons,” Mishra said. “First, we now know that the biological pathways are similar, but the differences are also important.” He added: “We saw that artemin levels were increased in cats with radiographic evidence of the disease, but that artemin levels didn’t correlate to veterinarian-assessed pain. However, knowing how difficult it is to measure pain in cats, in future work we will utilize technology to more objectively measure pain.”
The researchers suggest elevated artemin could serve as a diagnostic marker for DJD or even become a treatment target. “If veterinarians could do a blood test for increased artemin to diagnose DJD instead of X-rays it would save time and stress for cats,” Mishra said. “And perhaps targeting artemin expression could be therapy for either pain or disease progression.”
“Because cats exhibit naturally occurring DJD/OA similar to people, this work provides a valuable window into real biological processes and pain mechanisms which will ultimately improve clinical care for cats,” said Duncan Lascelles, professor of translational pain research at NC State.
The findings may also inform development of cross-species therapies as well as refine models used by scientists studying joint diseases.
