Influence of urinary sialic acid on calcium oxalate crystal formation.
Using seed crystal method, whole-urine method, and scanning electron microscopy, the inhibitory effects of sialic acid and osteopontin (OPN) on aggregation/growth of CaOx crystals were investigated. Using the seed crystal method, sialic acid showed an inhibitory effect on CaOx crystal aggregation/growth in a concentration-dependent manner, but almost no effect was observed using the whole-urine method. OPN showed an inhibitory effect on aggregation/growth in both experimental systems. The inhibitory effect of asialo-OPN on aggregation/growth was approximately 20% lower than that of OPN in the experiment using the seed crystal method and approximately 15% lower in the experiment using the whole-urine method. Scanning electron microscopy showed that OPN and sialic acid inhibit the aggregation of CaOx crystals. The above findings show that sialic acid accounts for about 15-20% of the involvement of OPN in CaOx crystallization.
Konya
E
E
Department of Urology, Kinki University School of Medicine, Osaka, Japan. urology@med.kindai.ac.jp
Amasaki
N
N
Umekawa
T
T
Iguchi
M
M
Kurita
T
T
D002129:Calcium Oxalate / Q000378:metabolism*; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D019158:N-Acetylneuraminic Acid / Q000652:urine*
D002129:Calcium Oxalate; D019158:N-Acetylneuraminic Acid