Untargeted Metabolomics Identify a Panel of Urinary Biomarkers for the Diagnosis of Urothelial Carcinoma of the Bladder, as Compared to Urolithiasis with or without Urinary Tract Infection in Dogs.

Maria Malvina Tsamouri,Carrie A Palm,Mamta Parikh,Michael S Kent,Paramita M Ghosh,William T N Culp,Blythe P Durbin-Johnson

doi:10.3390/metabo12030200

Maria Malvina Tsamouri, Carrie A Palm + Show 5 more

Open Access

https://doi.org/10.3390/metabo12030200

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Abstract

Urothelial carcinoma (UC), the most common urologic cancer in dogs, is often diagnosed late because the clinical signs are shared by other non-malignant lower urinary tract disorders (LUTD). The urine-based BRAFV595E test for UC is highly effective only in certain breeds; hence additional non-invasive biomarkers of UC are needed. Here, urine from dogs with UC (n = 27), urolithiasis (n = 8), or urolithiasis with urinary tract infection (UTI) (n = 8) were subjected to untargeted metabolomics analyses, using GC-TOF-MS for primary metabolites, QTOF-MS for complex lipids, and HILIC-QTOF MS for secondary and charged metabolites. After adjusting for age and sex, we identified 1123 known metabolites that were differentially expressed between UC and LUTD. Twenty-seven metabolites were significant (1.5 ≤ log2FC ≤ −1.5, adjusted p-value < 0.05); however, 10 of these could be attributed to treatment-related changes. Of the remaining 17, 6 (hippuric acid, N-Acetylphenylalanine, sarcosine, octanoylcarnitine, N-alpha-methylhistamine, glycerol-3-galactoside) discriminated between UC and LUTD (area under the ROC curve > 0.85). Of the 6 metabolites, only hippuric acid and N-alpha-methylhistamine were discriminatory in both male (n = 20) and female (n = 23) dogs, while sarcosine was an effective discriminator in several breeds, but only in females. Further investigation of these metabolites is warranted for potential use as non-invasive diagnostic biomarkers of dogs with UC that present with LUTD-related clinical signs.

Highlights

Urothelial carcinoma (UC) is the most common type of urinary bladder malignancy in dogs, affecting >50,000 dogs annually in the US
Other metabolites tested (Figure S3) failed to sufficiently discriminate between UC vs. control (Figure S4) despite being differentially expressed between the groups. These results identify 6 urine-based metabolites that can likely distinguish between UC vs. control groups
While a clinical test is available for the detection of UC in the urine, namely the BRAFV595E mutation analysis, this test was found to be more effective in terriers (73% carry the mutation), than in other breeds (36% carry the mutation) (p < 0.05) [22]

Summary

Introduction

Urothelial carcinoma (UC) is the most common type of urinary bladder malignancy in dogs, affecting >50,000 dogs annually in the US. Middle-aged or elderly female dogs are most commonly affected [1] Diagnosis of this disease is often challenging due to non-specific clinical signs, such as stranguria, pollakiuria, and hematuria as well as secondary bacterial infection. We previously evaluated the expression levels of 5 miRNA associated with UC pathophysiology (miR-34a, let-7c, miR-16, miR-103b, and miR-106b) in the blood and urine of dogs with UC vs LUTD [4].

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