Developing a Noninvasive Urine Test for Chronic Kidney Disease in Cats

SUMMARY: Researchers will develop and validate a test to improve our understanding of chronic kidney disease in cats and support future research into new treatments. 

THE PROBLEM: Chronic kidney disease affects a large percentage of senior cats and is a leading cause of death in this population. In the later disease stages, many cats have a reduced appetite and ability to undertake daily activities, creating distress for affected animals and their families. The need for frequent veterinary visits and administration of medications often compounds this. In addition, we do not fully understand how the disease progresses, which makes developing new treatments difficult.  

THE PROJECT: Treatments relating to a critical hormone system called the renin-angiotensin system (RAS) have been a big success in people with CKD. However, these are not widely used in cats with CKD because we do not have a clear picture of the degree to which the RAS is involved in feline CKD. Recently, scientists found that high levels of angiotensinogen (AGT) – a particular protein of the RAS – in the urine of people indicates the RAS is “turned on” and can predict whether a person with CKD is likely to experience worse outcomes. Unfortunately, we do not have a method to measure AGT in cats' urine. 

To address this issue, researchers will aim to develop a reliable way to measure the amount of AGT in cat urine. Researchers will employ an enzyme-linked immunosorbent assay test, as this method has successfully measured AGT in the urine of people and rodents. A possible pitfall of this tool is that it may require more work to gauge its accuracy in cats. To tackle this challenge, the team will use a second method called mass-spectrometry, which will help confirm that the ELISA test accurately measures AGT in the study’s cat urine samples.  

POTENTIAL IMPACT: In humans, RAS inhibitors are widely used in patients with CKD, effectively delaying its progression. The ability to accurately gauge RAS status in cats with CKD may open up the rational use of existing drugs similar to those used in people and guide the development of newer therapies targeting the RAS to help delay CKD progression in cats.