Not all cystinuric patients develop urinary calculi. There is the need to identify modulating factors. In recent years the role of trace elements in the mechanism of stone formation has received a steadily increasing attention. The aim of our study was to determine urinary excretion of trace elements in patients with recurrent cystine calculosis.
Material and methods: 11 patients with recurrent cystine calculosis and 15 healthy volunteers participated in the study. Urinary zinc, copper, chromium, boron and arsenic concentrations were determined by use of inductively coupled plasma-mass spectrometry (ICP-MS).
Results: There was a statistically significant difference between the patients with cystinuria and controls in mean arsenic urinary excretion (0.625+/-0.6 microg/kg body weight/24 h vs. 1.264+/-0.635 microg/kg b.w./24 h, p=0.02). There was also a noticeable difference in urinary chromium, the mean concentration of which was higher in case of the patients with cystinuria (3.32+/-3.59 microg/kg/24 h) than in the controls (1.38+/-0.69 microg/kg/24 h). The mean urinary excretion of zinc, copper, and boron (in microg/kg b.w./24 h) were respectively 7.40+/-7.98; 1.33+/-0.48; 26.55+/-15.81 in the patients with cystinuria and 9.84+/-5.33; 1.16+/-0.84; 35.87+/-13.76 in the controls.
Conclusion: It seems that a decreased excretion of arsenic may contribute to the development of cystine calculosis.