Influence of an Orally Administered Glycosaminoglycan Preparation on Urinary Saturation for Calcium Oxalate and Struvite in Healthy Cats
Glycosaminoglycans are recommended commonly for treatment of osteoarthritis and feline idiopathic cystitis; however, they may also have a role in urolith formation. Glycosaminoglycans inhibit crystal and urolith formation, and decreased urinary levels of glycosaminoglycans are associated with increased risk of calcium oxalate urolith formation in human beings. During urolith formation and growth, glycosaminoglycans are incorporated into the urolith matrix; therefore, they may also promote urolith formation and growth. We hypothesized that oral administration of a commercially available preparation containing chondroitin sulfate and glucosamine, commonly used for treating osteoarthritis in dogs and cats, to healthy adult female cats would be associated with increased urinary relative supersaturation for calcium oxalate and struvite. Our objectives were to evaluate administration of a commercially available compound containing chondroitin sulfate and glucosamine used for management of osteoarthritis and idiopathic cystitis in cats on urinary excretion of electrolytes and minerals, and urinary saturation for calcium oxalate.
Six healthy, spayed female cats, aged 4-6 years, and weighing 3.5-6.5 kg, were evaluated. Twenty-four urine samples were collected before and after administration of an oral glycosaminoglycan preparation at recommended dosage for management of osteoarthritis (Cosequin, Nutramax Laboratories) for two weeks. Twenty-four hour urine samples were collected using a modified litter box. A dry, adult maintenance food (SportMix, Midwestern Pet Foods) was fed to maintain body weight and condition. Twenty-four hour urine samples were mixed, the volume recorded, and pH, sodium, potassium, chloride, calcium, magnesium, phosphorous, citrate, oxalate, and ammonia concentrations were determined. Molar concentrations of these analytes were entered into a computer program (EQUIL 89d, University of Florida) for determination of relative supersaturation for calcium oxalate monohydrate and dihydrate, and struvite. Data were analyzed using 2-tailed, paired t-tests; p < 0.05 was significant.
Body weight did not change between the start and finish of the treatment period. Significant differences were not found for 24-hour urine pH, 24-hour urine volume, 24-hour urinary excretion of minerals or electrolytes, or for urinary relative supersaturation of calcium oxalate or struvite.
Oral administration of a commercially available glycosaminoglycan preparation at recommended dosages for two weeks did not increase or decrease urinary saturation for calcium oxalate or struvite in healthy adult female cats.