Comparative Study of Urinary N-Acetyl-Beta-D-Glucosaminidase Levels, Urinary Glycosaminoglycans and Plasma Glycosaminoglycans Levels in Cats With Feline Idiopathic Cystitis

Abstract

Comparative study was conducted to measure urinary N-acetyl-?-glucosaminidase (NAG), urinary glycosaminoglycans (GAGs) and plasma glycosaminoglycans (GAGs) in cats with feline idiopathic cystitis (FIC). A standard questionnaire was designed to gather information for all cats including signalment, characteristics, environment, type of food and management of the cats? litter box to evaluate the risk factors for developing FIC. Blood and urine samples were collected from 19 clinically normal cats and 19 aged and sex matched cats with FIC. Concentration of urinary NAG, urinary GAGs and plasma GAGs were measured by colorimetric method. NAG index and GAGs-to-creatinine ratio were calculated. The results demonstrated that cats with body condition score >3/5 (OR = 4.96; 95% CI 0.873-28.152), castrated male (OR = 2.36; 95% CI 0.640-8.667) and longhaired-cats (OR = 8.31; 95% CI 0.890-77.568) tend to be the risk factor for developing FIC. On the contrary, domestic shorthair breed (OR = 0.09; 95% CI 0.010-0.876) was the protective factors for FIC. Cats with FIC were significantly more likely to use a litter box than clinically normal cats (OR = 14.57; 95% CI 2.566-82.732). Cats with FIC had significantly higher NAG index (2.36 ? 0.69 U/g) than clinically normal cats (1.00 ? 0.21 U/g) (p < 0.05). The cats with FIC had lower GAGs-to-creatinine ratio (3.84 ? 0.52 x103) than clinically normal cats (4.52 ? 0.76 x103) but the values were not significantly different. The Urine protein to creatinine ratio (UPC) and NAG index presented the significant moderate positive correlation (r = 0.511, p < 0.05) in cats with FIC. These finding suggested that the increased NAG index might play a role as a biomarker for identifying and assessing progressive idiopathic cystitis, particularly in cats with proteinuria condition. It was possibly that cats with FIC had some complications related to the kidney dysfunction prior to the development of FIC. This defective GAGs layer in cats with FIC resulting in decreased urinary GAGs excretion and GAGs-to-creatinine ratio might relate to the increased lysosomal enzyme such as NAG from the kidney.