Effects of oral administration of N-acetyl-d-glucosamine on plasma and urine concentrations of glycosaminoglycans in cats with idiopathic cystitis.

OBJECTIVE To determine the effects of once-daily oral administration of N-acetyl-d-glucosamine (NAG) on plasma and urine glycosaminoglycan (GAG) concentrations in cats with idiopathic cystitis (IC). ANIMALS 19 cats with IC and 10 clinically normal cats. PROCEDURES Cats with IC were randomly assigned to receive 250 mg of NAG in capsule form orally once daily for 28 days (n = 12) or a placebo (capsule containing cellulose) orally once daily for the same period (7). In cats with IC, plasma and urine GAG concentrations and urine creatinine concentration were measured on days 0 (immediately before first dose), 7, 14, 21, 28, and 56. For purposes of comparison, those variables were measured in 10 clinically normal cats on day 0. RESULTS Mean ± SEM urine GAG-to-creatinine concentration ratios (day 0 data) for cats with IC and clinically normal cats differed significantly (3.11 ± 0.62 μg/mL and 14.23 ± 3.47 μg/mL, respectively). For cats with IC, mean plasma GAG concentration in NAG-treated cats (39.96 ± 5.34 μg/mL) was higher than that in placebo-treated cats (24.20 ± 3.35 μg/mL) on day 21. In the NAG-treated cats, plasma GAG concentration on days 21 (39.96 ± 5.34 μg/mL) and 28 (39.91 ± 6.74 μg/mL) differed significantly from the day 0 concentration (27.46 ± 3.90μg/mL). CONCLUSIONS AND CLINICAL RELEVANCE Cats with IC have lower urinary GAG-to-creatinine concentration ratios than did clinically normal cats. Administration of NAG (250 mg, PO, q 24 h) significantly increased plasma GAG concentrations in cats with IC after 21 days of treatment.