Accessible Requires Authentication Published by De Gruyter July 5, 2005

Effects of urine dilution on quantity, size and aggregation of calcium oxalate crystals induced in vitro by an oxalate load

Angela Guerra, Franca Allegri, Tiziana Meschi, Giuditta Adorni, Beatrice Prati, Antonio Nouvenne, Almerico Novarini, Umberto Maggiore, Enrico Fiaccadori and Loris Borghi

Abstract

Increasing urinary volume is an important tool in the prevention of calcium renal stones. However, the mechanism of how it actually works is only partially understood. This study aimed at assessing how urine dilution affects urinary calcium oxalate crystallization. A total of 16 male idiopathic calcium oxalate (CaOx) stone-formers and 12 normal male subjects were studied and 4 h urine samples were taken twice, under low (undiluted urine) and high hydration conditions (diluted urine). An equal oxalate load (1.3mmol/L) was added to both types of urine and the crystallization parameters were assessed. In both stone-formers and normal subjects, the crystallization processes were significantly (p<0.05 or less) more marked in the undiluted urine than in the diluted urine in terms of: a) total quantity of calcium oxalate dihydrate (COD) and calcium oxalate monohydrate (COM) crystals; b) total quantity of crystalline aggregates; and c) aggregation index (i.e., ratio between the area occupied by crystalline aggregates and the area occupied by all the crystals present). The comparison between stone-formers and normal subjects showed that the greatest difference was for the size of COD crystals, which were larger in the urine of the stone-formers. A further important finding was an inverse relationship between changes in urinary volume and in the aggregation index (r=–0.53, p=0.004). In conclusion, urine dilution considerably reduces crystallization phenomena induced in vitro by an oxalate load in both calcium stone-formers and normal subjects.


Corresponding author: Loris Borghi MD, Dipartimento di Scienze Cliniche, Università di Parma, Via Gramsci 14, 43100 Parma, Italy Phone: +39-0521-702007, Fax: +39-0521-940993,

References

1 Pak CY, Sakhaee K, Crowther C, Brinkley L. Evidence justifying a high fluid intake in treatment of nephrolithiasis. Ann Intern Med 1980; 93: 36–9. Search in Google Scholar

2 Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. J Urol 1996; 155: 839–43. Search in Google Scholar

3 Borghi L, Meschi T, Schianchi T, Briganti A, Guerra A, Allegri F, et al. Urine volume: stone risk factor and preventive measure. Nephron 1999; 81(Suppl 1): 31–7. Search in Google Scholar

4 Borghi L, Guerra A, Meschi T, Briganti A, Schianchi T, Allegri F, et al. Relationship between supersaturation and calcium oxalate crystallization in normals and idiopathic calcium oxalate stone formers. Kidney Int 1999; 55: 1041–50. Search in Google Scholar

5 Guerra A, Meschi T, Allegri F, Schianchi T, Adorni G, Novarini A, et al. Calcium oxalate crystallization in untreated urine, centrifuged and filtered urine and ultrafiltered urine. Clin Chem Lab Med 2004; 42: 45–50. Search in Google Scholar

6 Baumann JM, Affolter B, Brenneisen J, Siegrist HP. Measurement of metastability, growth and aggregation of calcium oxalate in native urine. Urol Int 1997; 59: 214–20. Search in Google Scholar

7 Hess B, Kok DJ. Nucleation, growth, and aggregation of stone-forming crystals. In: Coe FL, Favus MJ, Pak CY, Parks JH, Preminger GM, editors. Kidney stones: medical and surgical management. Philadelphia: Lippincott-Raven, 1996:3–32. Search in Google Scholar

8 Hallson PC, Rose GA. Uromucoids and urinary stone formation. Lancet 1979; 12: 1000–2. Search in Google Scholar

9 Kok DJ, Papapoulos SE, Bijvoet OL. Excessive crystal agglomeration with low citrate excretion in recurrent stone-formers. Lancet 1986; 10: 1056–8. Search in Google Scholar

10 Edyvane KA, Hibberd CM, Harnett RM, Marshall VR, Ryall RL. Macromolecules inhibit calcium oxalate crystal growth and aggregation in whole human urine. Clin Chim Acta 1987; 167: 329–38. Search in Google Scholar

11 Hess B, Nakagawa Y, Coe FL. Inhibition of calcium oxalate monohydrate crystal aggregation by urine proteins. Am J Physiol 1989; 257: F99–F106. Search in Google Scholar

12 Ebisuno S, Kohjimoto Y, Yoshida T, Ohkawa T. Effect of urinary macromolecules on aggregation of calcium oxalate in recurrent calcium stone formers and healthy. Urol Res 1993; 21: 265–8. Search in Google Scholar

13 Hess B. Tamm-Horsfall glycoprotein and calcium nephrolithiasis. Mineral Electrolyte Metab 1994; 20: 393–8. Search in Google Scholar

14 Khan SR. Interactions between stone-forming calcific crystals and macromolecules. Urol Int 1997; 59: 59–71. Search in Google Scholar

15 Hess B. Tamm-Horsfall glycoprotein – inhibitor or promoter of calcium oxalate monohydrate crystallization processes? Urol Res 1992; 20: 83–6. Search in Google Scholar

16 Ackermann D, Brown P, Khan SR. Preparation and application of calcium oxalate dihydrate crystal seeds. Urol Res 1989; 17: 147–8. Search in Google Scholar

17 Yuzawa M, Tozuka K, Tokue A. Effect of citrate and pyrophosphate on the stability of calcium oxalate dihydrate. Urol Res 1998; 26: 83–8. Search in Google Scholar

18 Berg W, Hesse A, Schneider HJ. A contribution to the formation mechanism of calcium oxalate urinary calculi. III. On the role of magnesium in the formation of oxalate calculi. Urol Res 1976; 4: 161–7. Search in Google Scholar

19 Worcester EM. Urinary calcium oxalate crystal growth inhibitors. J Am Soc Nephrol 1994; 5(Suppl 1): 46–53. Search in Google Scholar

20 Robertson WG, Peacock M. Calcium oxalate crystalluria and inhibitors of crystallization in recurrent renal stone-formers. Clin Sci 1972; 43: 499–506. Search in Google Scholar

Received: 2005-1-24
Accepted: 2005-3-30
Published Online: 2005-7-5
Published in Print: 2005-6-1

© Walter de Gruyter Berlin New York