What Do We Know About Cyclooxygenases Expression in the Lower Urinary Tract of Dogs and Cats? A Systematic Review

Cyclooxygenases (COX-1 and COX-2) are key enzymes in the biosynthesis of prostanoids, which mediate physiological functions, inflammation, and the process of carcinogenesis. In dogs and cats, lower urinary tract diseases are prevalent and often complex, requiring targeted therapeutic interventions. Although the role of cyclooxygenases is well established in humans, their expression profile in dogs and cats remains underexplored. This systematic review aimed to consolidate the available knowledge regarding the expression of COX-1 and COX-2 in the lower urinary tract tissues of dogs and cats, highlighting pathological implications and gaps in the literature. A total of 28 original studies were included in this review, which employed methodologies such as immunohistochemistry (IHC), Western blotting (WB), in situ hybridization (ISH), RNA sequencing, and ELISA. The urinary bladder was the most frequently analyzed tissue, followed by the urethra. COX-2 expression was predominantly elevated in tissues with inflammation or neoplasia, whereas COX-1 exhibited a constitutive expression pattern in normal tissues. In cats with feline idiopathic cystitis (FIC), COX-2 expression was significantly elevated in the urethral mucosa. In cases of transitional cell carcinoma (TCC), COX-2 expression varied substantially. The consistent expression of COX-1 in both normal and altered tissues suggested a homeostatic role. Despite the potential of COX-2 as a therapeutic target and prognostic marker, methodological heterogeneity, small sample sizes, and the lack of standardized criteria limit the comparability of findings. This review underscores the need for well-designed studies and standardized approaches to better understand the role of COX enzymes in the uropathology of small animals.