Study reveals insights into feline chronic kidney disease
Researchers found differentially expressed proteins between cats with hypertensive CKD and cats with normotensive CKD.
Researchers have found potential biomarkers in feline urine.
A new study, published in the latest issue of the Journal of Small Animal Practice (JSAP), has successfully isolated extracellular vesicles from cat urine and discovered differentially expressed proteins between cats with normotensive chronic kidney disease (CKD) and hypertensive CKD. 

It is the first study to characterise the proteome of feline urinary extracellular vesicles that originate in the kidney and could be a source of biomarkers for disease progression and potential therapeutic targets.

Nicola Di Girolamo, the editor of JSAP, said in response to the study: “CKD is particularly common in geriatric cats and associated hypertension can contribute to morbidity, so the search for factors associated with disease is highly valuable.”

The researchers used three different methods (precipitation, precipitation followed by size exclusion chromatography, and ultrafiltration followed by exclusion chromatography) to isolate extracellular vesicles from stored urine samples from a sample of 28 cats. Nine cats were classed with normal renal function, 10 with normotensive CKD and nine with hypertensive CKD. 

Unexpectedly, the study found no differential protein expression between the extracellular vesicles of cats with normal renal function and those with either normotensive CKD or hypertensive CKD. This surprising result may have been due to the small category sizes used in the study.

However, the researchers did find a total of five differentially expressed proteins between cats with hypertensive CKD and cats with normotensive CKD. These included increased expression of aminopeptidase and decreased expression of alpha-2-macroglobulin, cauxin, inter-alpha-trypsin inhibitor heavy chain 4 and transferrin.

The authors of the study concluded that further investigation is warranted into the usefulness of these proteins as therapeutic targets or biomarkers.

The study, 'Urinary extracellular vesicles as a source of protein-based biomarkers in feline chronic kidney disease and hypertension', can be read online or in the January issue of JSAP. The research was funded by the BSAVA through its fundraising and grant-awarding arm, PetSavers.