Reduced crystallization inhibition by urine from women with nephrolithiasis.
BACKGROUND
Human urine is known to inhibit growth, aggregation, nucleation, and cell adhesion of calcium oxalate monohydrate (COM) crystals, the main solid phase of human kidney stones. This study tested the hypothesis that low levels of inhibition are present in women with calcium oxalate stones and, therefore, could promote stone production.


METHODS
In 17 stone-forming women and 17 normal women matched in age within five years, inhibition by dialyzed urine proteins of COM growth and aggregation was examined, as well as whole urine upper limits of metastability (ULM) for COM and calcium phosphate (CaP) in relation to the corresponding supersaturation (SS).


RESULTS
Compared to normals, patient urine showed a reduced ULM in relation to SS. In contrast to men, there was no difference in growth inhibition.


CONCLUSIONS
Reduced CaP and CaOx ULM values in relation to SS are a characteristic of female stone formers. This defect could promote stones by facilitating crystal nucleation. Abnormal inhibition may well be a very important cause of human nephrolithiasis.
Asplin
John R
JR
Renal Section, University of Chicago, and Litholink Corporation, Chicago, Illinois 60637, USA.
Parks
Joan H
JH
Nakagawa
Yashushi
Y
Coe
Fredric L
FL
D000818:Animals; D002118:Calcium / Q000652:urine; D002129:Calcium Oxalate / Q000652:urine; D019343:Citric Acid / Q000652:urine; D003460:Crystallization; D005260:Female; D011897:Random Allocation; D012307:Risk Factors; D012737:Sex Factors; D014527:Uric Acid / Q000652:urine; D014545:Urinary Calculi / Q000737:chemistry / Q000453:epidemiology / Q000652:urine; D014556:Urine / Q000737:chemistry*
D002129:Calcium Oxalate; D014527:Uric Acid; D019343:Citric Acid; D002118:Calcium