The effect of traditional risk factors for stone disease on calcium oxalate crystal adherence in the rat bladder

Crystal adherence in the urinary tract has been studied using the chemically injured rat bladder and cell cultures. These studies have provided evidence that mucin prevents adherence and have studied various compounds for their ability to promote or inhibit crystal adherence. Little work has been done examining the effect on crystal adherence of traditional risk factors for stone disease. The study reported here examined the effect hypercalciuria, hyperoxaluria and pH on calcium oxalate crystal adherence using the intact rat bladder model. Calcium at levels seen in hypercalciuric stone formers was associated with increased adherence. Oxalate at levels seen in stone formers had no effect on adherence. There was a tendency to increased crystal adherence at higher pH values only when phosphorus was present as the buffer. Hypercalciuria is a risk factor for stone disease by increasing the level of saturation of calcium oxalate and calcium phosphate in the urine and by decreasing inhibitor function. This study suggests that it may also play a role by increasing crystal adherence within the urinary tract.