Reduced crystallization inhibition by urine from men 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 tests the hypothesis that low levels of inhibition are present in men with calcium oxalate stones and could therefore promote stone production.


METHODS
In 17 stone-forming men and 17 normal men that were matched in age to within five years, we studied the inhibition by dialyzed urine proteins of COM growth, aggregation, and binding to cultured BSC-1 renal cells, as well as whole urine upper limits of metastability (ULM) for COM and calcium phosphate (CaP) in relationship to the corresponding supersaturation (SS).


RESULTS
Compared with normals, patient urine showed reduced COM growth inhibition and reduced ULM in relationship to SS. When individual defects were considered, 15 of the 17 patients were abnormal in one or more inhibition measurements. ULM and growth inhibition defects frequently coexisted.


CONCLUSIONS
Reduced COM growth and CaP and CaOx ULM values in relationship to SS are a characteristic of male stone formers. Both defects could promote stones by facilitating crystal nucleation and growth. Abnormal inhibition may be a very important cause of human nephrolithiasis.
Asplin
J R
JR
Renal Section, Department of Medicine, University of Chicago, Illinois 60637, USA.
Parks
J H
JH
Chen
M S
MS
Lieske
J C
JC
Toback
F G
FG
Pillay
S N
SN
Nakagawa
Y
Y
Coe
F L
FL
D002118:Calcium / Q000652:urine; D002129:Calcium Oxalate / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry; D002951:Citrates / Q000652:urine; D003460:Crystallization; D006801:Humans; D007669:Kidney Calculi / Q000652:urine*; D008297:Male; D010758:Phosphorus / Q000652:urine; D011188:Potassium / Q000652:urine; D000644:Quaternary Ammonium Compounds / Q000652:urine; D012737:Sex Factors; D012964:Sodium / Q000652:urine; D012995:Solubility; D014556:Urine / Q000737:chemistry*
D002130:Calcium Phosphates; D002951:Citrates; D000644:Quaternary Ammonium Compounds; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002129:Calcium Oxalate; D010758:Phosphorus; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D012964:Sodium; C485829:calcium phosphate, dibasic, anhydrous; D011188:Potassium; D002118:Calcium