Calcium phosphate crystal-associated proteins: alpha2-HS-glycoprotein, prothrombin F1, and osteopontin.
OBJECTIVE
To elucidate the process of urinary stone formation, many urinary constituents have been examined as inhibitors or promoters.


METHODS
We analyzed specific binding proteins of calcium phosphate (CaP) crystals generated in human urine and found that the separated proteins were alpha2-HS-glycoprotein, prothrombin fragment 1 (PTF1), and osteopontin (OPN). We also studied their inhibitory effects on calcium oxalate crystallization and the quantitative differences in urinary excretion of the proteins in healthy individuals and stone formers.


RESULTS
Both PTF1 and OPN had strong inhibitory effects on growth of calcium oxalate crystals. No differences in alpha2-HS-glycoprotein were found between healthy subjects and stone formers. Urinary concentrations of PTF1 and OPN were lower in stone formers than in healthy controls. No differences in these proteins were seen between single and recurrent stone formers.


CONCLUSIONS
Low urinary concentrations of PTF1 and OPN might be one reason for stone formation.
Nishio
S
S
Department of Urology, Ehime University School of Medicine, Ehime, Japan. nishio@m.ehime-u.ac.jp
Hatanaka
M
M
Takeda
H
H
Aoki
K
K
Iseda
T
T
Iwata
H
H
Yokoyama
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000737:chemistry* / Q000652:urine; D017610:Calcium Compounds / Q000494:pharmacology; D002130:Calcium Phosphates / Q000737:chemistry*; D016022:Case-Control Studies; D002852:Chromatography, Ion Exchange; D003460:Crystallization; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D053495:Osteopontin; D010087:Oxides / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry* / Q000652:urine; D011498:Protein Precursors / Q000737:chemistry* / Q000652:urine; D011516:Prothrombin / Q000737:chemistry* / Q000652:urine; D020539:Sequence Analysis, Protein; D012795:Sialoglycoproteins / Q000737:chemistry* / Q000652:urine; D014545:Urinary Calculi / Q000737:chemistry / Q000209:etiology*; D060749:alpha-2-HS-Glycoprotein
C556354:AHSG protein, human; D001798:Blood Proteins; D017610:Calcium Compounds; D002130:Calcium Phosphates; D010087:Oxides; D010446:Peptide Fragments; D011498:Protein Precursors; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D060749:alpha-2-HS-Glycoprotein; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D053495:Osteopontin; C485838:calcium phosphate, monobasic, anhydrous; C029733:prothrombin fragment 1; D011516:Prothrombin; C020243:calcium phosphate; C016538:lime; C485829:calcium phosphate, dibasic, anhydrous