Decreased urine glycosaminoglycan excretion in cats with interstitial cystitis

Purpose: The urine protein and glycosaminoglycan (GAG) excretion of normal cats was compared with that of cats suffering from interstitial cystitis (IC), which is reported to decrease urine GAG excretion in humans. Materials and Methods: Total urine GAG; concentration was measured in random and 24-hour urine specimens by spectrophotometry by 1,9-dimethylmethylene blue (DMB) chloride. Results: In both random and 24-hour urine samples, GAG and protein concentrations and GAG:creatinine and protein:creatinine ratios all were significantly lower in cats with IC. Total GAG and protein excretion also were significantly lower in 24-hour urine samples from cats with IC. Conclusions: GAG excretion was decreased in cats with IC, as it is in humans. It is unclear whether this is due to changes in synthesis, metabolism, or bladder permeability.