# Serum and Urinary Uromodulin in Dogs with Early Chronic Kidney Disease vs. Healthy Canine Population

## TL;DR

The study compares serum and urinary uromodulin levels in dogs with early chronic kidney disease and healthy dogs to identify better biomarkers for early diagnosis.

## Contribution

The study identifies urinary uromodulin corrected to creatinine as a promising early marker for chronic kidney disease in dogs.

## Key findings

- Urinary uromodulin indexed to creatinine was significantly reduced in dogs with stage 2 CKD.
- Urinary uromodulin correlated with kidney disease markers SDMA and UPC in stage 1 CKD.
- Serum uromodulin was not affected by age, gender, or CKD stage.

## Abstract

Simple Summary: Uromodulin has been known for many years as a normal protein component of urine. However, in recent years, serum as well as urinary uromodulin have been investigated in relation to kidney diseases. Chronic kidney disease (CKD) is a common diagnosis, especially in old dogs, and suitable markers for the early stages of the disease are constantly being investigated. We focused on the effect of age and gender on uromodulin in serum and urine in a healthy population of dogs of the same breed, German shepherd. We compared the results with two groups of other breeds of healthy dogs. Compared with groups of patients in the early stages of CKD, we concluded that urinary uromodulin corrected to creatinine in urine seems to be the most prospective marker.

Serum and urinary uromodulin are evaluated as potential biomarkers of kidney disease. The aim of our research was to select a more appropriate form of uromodulin for the diagnosis of early stages of chronic kidney disease (CKD). We also focused on the influence of age and gender in one breed on uromodulin and on the possible interbreed differences. Serum uromodulin had the lowest values in dogs younger than 2 years but no effect of gender, breed, or CKD was observed. Urinary uromodulin indexed to urinary creatinine was significantly reduced in dogs in stage 2 of CKD (p = 0.003) in contrast to uromodulin converted to urine specific gravity. Urinary uromodulin with both corrections was significantly lower in Belgian shepherds compared to German shepherds (p < 0.0001, p = 0.0054) but was not influenced by gender or age. In stage 1 of CKD, urinary uromodulin correlated with kidney disease markers SDMA (p = 0.0424, p = 0.0214) and UPC (p = 0.0050, p = 0.0024). Urinary uromodulin appears to be more associated with CKD than serum uromodulin. Further studies with a larger number of patients are needed for the suitability of urinary uromodulin as a marker of early-stage disease.