Evidence that calgranulin is produced by kidney cells and is an
inhibitor of calcium oxalate crystallization.
Pillay, Sokalingum N., John R. Asplin, and Fredric L. Coe.
Department of Medicine, Section of Nephrology, MC5100, University
of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637, Phone #773-702
-9463, Fax #773-702-5818
APStracts 5:0079F, 1998.
Urine produced by normal human kidneys is almost always supersaturated
with respect to calcium oxalate (CaOx), the most common constituent
of human kidney stones. Crystallization, with risk of renal damage
and kidney stones, appears to be affected by molecules in urine that
retard nucleation, growth, aggregation, and renal cell adherence of
CaOx. The repertoire of such molecules is incompletely known. We have
purified a 28 kd protein from urine using salt precipitation,
preparative isoelectric focusing, and sizing chromatography. Amino
acid composition and N-terminal amino sequence analysis showed
complete homology to calgranulin. Calgranulin was found to be a
potent inhibitor of CaOx crystal growth (44% of control) and
aggregation (50% of control) in the nM range. Calgranulin cDNA was
cloned from a human kidney expression library. Western analysis of
human and rat kidney homogenates and mRNA temporal expression from
two independent renal epithelial cell lines showed that calgranulin
is produced in the kidney. Given its urinary abundance and potency,
calgranulin may contribute importantly to the normal urinary
inhibition of crystal growth and aggregation, and therefore to the
renal defense against clinical stone disease.
Received 21 November 1997; accepted in final form 26 March 1998.
APS Manuscript Number F365-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 24 April 1998