•  
  •  
 

Abstract

The main purpose of this research was to evaluate the effect of high calcium intake on the parameters of calcium balance and the risk of occurrence of urolithiasis in rabbits. Twenty-four adult rabbits (New Zealand White) were divided into two groups - experimental and control, where the first group was provided with increased calcium content in diet, while the second one received usual amount of calcium for a definite period. The following parameters were evaluated in both groups: total calcium content in blood, blood phosphorus, fractional excretion of calcium (FECa), glomerular filtration rate (GFR), urine pH, nephrocalcin content in urine, urine biochemical examination, and urine sediment analysis. In turn, animals on the high-calcium diet had elevated serum total calcium, FECa, urinary Ca, and urinary pH, but reduced neprocalcin in urine. Clearly, there are several factors, such as the enhanced excretion of calcium by the kidneys, acid-base imbalance leading to the development of alkalic urine with the super saturation with calcium carbonate, and lack of inhibition for crystals aggregation, which promote the formation of conditions suitable for the formation of stones. The normal level of GFR in spite of elevated values of FECa suggests that at this stage the reaction of the kidneys occurs only at the tubule level, and no signs of filtration dysfunction were found. Thus, in general, this research can be considered as evidence in favor of the multifactor theory of calcium urolithiasis.

References

[1] ScienceDirect. Calcium and phosphorus homeostasis in rabbits [Internet]. Available from: https://www. sciencedirect.com/science/article/abs/pii/ S0009912014000034.

[2] PMC. Fractional excretion of calcium and renal function in rabbits [Internet]. Available from: https://pmc.ncbi.nlm.nih. gov/articles/PMC12433243/.

[3] PMC. Glomerular filtration rate measurement using exogenous markers [Internet]. Available from:: https://pmc.ncbi. nlm.nih.gov/articles/PMC9710478/.

[4] PMC. Iohexol clearance methodology [Internet]. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5489626/.

[5] PMC. Fractional excretion of calcium formula and clinical application [Internet]. Available from: https://pmc.ncbi.nlm. nih.gov/articles/PMC11104238/.

[6] AbdominalKey. Kinetic modeling and adequacy in PD [Internet]. Available from:: https://abdominalkey.com/ kinetic-modeling-and-adequacy-in-pd/.

[7] PMC. Glomerular filtration rate clearance methods [Internet]. Available from: https://pmc.ncbi.nlm.nih.gov/ articles/PMC2329278/.

[8] Cat.life. Diagnosis: blood tests for renal function [Internet]. Available from: https://cat.life/en/diagnosis/blood-tests/.

[9] FVTM. Urinalysis and urine pH assessment in rabbits [Internet]. Available from: https://fvtm.stafpu.bu.edu.eg/ Animal20medicine/948/publications/Ameer20Ahmed20AbdElhameed20Megahed_1-s2.0-S0022030219308306-main.pdf.

[10] JaypeeDigital. Laboratory evaluation of urine [Internet]. Available from: https://www.jaypeedigital.com/eReader/ chapter/9789380704197/ch1.

[11] Clauss M, Burger B, Liesegang A, Del Chicca F, KaufmannBart M, Riond B, et al. Influence of diet on calcium metabolism, tissue calcification and urinary sludge in rabbits (Oryctolagus cuniculus). J Anim Physiol Anim Nutr 2012 Oct; 96(5):798—807.

[12] Lulich JP, Berent AC, Adams LG, Westropp JL, Bartges JW, Osborne CA. ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats. J Vet Intern Med 2016;30(5):1564—74. https:// doi.org/10.1111/jvim.14559. Epub 2016 Sep 9. PMID: 27611724; PMCID: PMC5032870.

[13] Eckermann-Ross C. Hormonal regulation and calcium metabolism in the rabbit. Vet Clin Exot Anim Pract 2008 Jan 1;11(1):139—52. https://doi.org/10.1016/j.cvex.2007.09.002. PMID: 18165142.

[14] Eckermann-Ross C. Hormonal regulation and calcium metabolism in the rabbit. Vet Clin North Am Exot Anim Pract 2008 Jan;11(1):139—52. https://doi.org/10.1016/ j.cvex.2007.09.002. PMID: 18165142.

[15] Colette C, Percheron C, Pham CT, Boniface H, Thomas N, Guiter J, et al. Renal handling of calcium in hypercalciuric calcium oxalate nephrolithiasis. Miner Electrolyte Metab 1993;19(6):377—84. PMID: 8164620.

[16] Liesegang A, Burger B, de Vries de Heekelingen T, Schroeter-Vogt C, Hatt JM, Kowalewski MP, et al. Rabbits (Oryctolagus cuniculus) increase caecal calcium absorption at increasing dietary calcium levels. J Anim Physiol Anim Nutr 2024 Jan;108(1):185—93. https://doi.org/10.1111/jpn.13880. Epub 2023 Sep 4. PMID: 37664966.

[17] Carvalho M, Lulich JP, Osborne CA, Nakagawa Y. Defective urinary crystallization inhibition and urinary stone formation. Int Braz J Urol 2006 May-Jun;32(3):342—8. https:// doi.org/10.1590/s1677-55382006000300016. discussion 349 PMID: 16813682.

[18] Tonneijck L, Muskiet MH, Smits MM, van Bommel EJ, Heerspink HJ, van Raalte DH, et al. Glomerular hyperfiltration in diabetes: mechanisms, clinical significance, and treatment. J Am Soc Nephrol 2017 Apr;28(4):1023—39. https://doi.org/10.1681/ASN.2016060666. Epub 2017 Jan 31. PMID: 28143897; PMCID: PMC5373460.

[19] Polzin DJ. Chronic kidney disease in small animals. Vet Clin North Am Small Anim Pract 2011 Jan;41(1):15—30. https:// doi.org/10.1016/j.cvsm.2010.09.004. Epub 2010 Dec 4. PMID: 21251509.

[20] Jewell DE, Tavener SK, Hollar RL, Panickar KS. Urine metabolomic changes in cats with renal disease or calcium oxalate uroliths. PLoS One 2025 Aug 18;20(8):e0329999. https://doi.org/10.1371/journal.pone.0329999. PMID: 40824970; PMCID: PMC12360560.

[21] Pak CY. Citrate and renal calculi: new insights and future directions. Am J Kidney Dis 1991 Apr;17(4):420—5. https:// doi.org/10.1016/s0272-6386(12)80635-4. PMID: 2008910.

[22] Hu B, Wu HR, Ma ZY, Wu ZC, Lu YM, Shi GW. Involvement of VKORC1 in the inhibition of calcium oxalate crystal formation in HK-2 cells. J Huazhong Univ Sci Technolog Med Sci 2014 Jun;34(3):376—81. https://doi.org/10.1007/ s11596-014-1286-0. Epub 2014 Jun 18. PMID: 24939302.

[23] Thongboonkerd V. Proteomics of crystal—cell interactions: a model for kidney stone research. Cells 2019;8(9):1076. https://doi.org/10.3390/cells8091076.

Download

Share

COinS