Calcium binding parameters of tissue structures in kidney recipients acute hypercalcaemia

Calcium binding cooperative parameters by tissue was analysed in 28 kidney recipients (19 men and 9 women, 32 ± 12 years old) with sufficient graft function. Patients received triple immunosuppression (cyclosporine, metipred, azathioprine) under conditions of acute hypercalcaemia followed by a drip IV infusion of calcium gluconate over 2,5 hours. At the end of each 30-minute period the amount of calcium retained by tissue was recorded and the kinetic parameters of calcium binding were determined according to Langmuir and Scatchard. In all recipients there was a segment of binding isotherm with positive cooperativity (direct regression in Scatchard) with normal buffer capacity (b) for calcium in Langmuir. 7 recipients in early and 9- in late date after operation demonstrated cooperativity at [Ca⁺⁺] 1,0–1,3 mmol/l (first variant in health) while 10 recipients in early and 2 in late date – at [Ca⁺⁺] 1,3–1,5 (second variant in health). 6 from 13 kidney recipients showed disturbed tissue structure calcium binding parameters with [Ca⁺⁺] 1 mmol/l namely decreased the association constant (Ka), increased the number of interactive sites (n), reduced calcium exchangeable pool (Me). Additionally, [Ca⁺⁺] at Me = 0 was elevated that means the shift of calcium binding curve to the right that may predispose to hypercalcaemia. Glucocorticoid therapy, hyperparathyreose, hypocalcitoninaemia were not the reasons of these disturbances.

kidney allotransplantation, hypercalcaemia, tissue proteins, calcium binding cooperative properties of tissue proteins, kinetic parameters, аллотрансплантация почки, гиперкальциемия, тканевые белки, кооперативное связывание кальция тканевыми белками

1. Бородулин И.Э. Реабсорбция кальция, магния и фосфора после аллотрансплантации трупной почки // Дисс.-канд. мед. наук. М., 2008.

2. Бородулин И.Э., Пронченко И.А., Шмерко Н.П. и др. Методические подходы к выявлению механизмов развития гипер- и гипокальциемии после аллотрансплантации почки // Нефрология и диализ. 2010. № 3. С. 179–183.

3. Ермакова И.П., Бузулина В.П., Пронченко И.А. Кальцийсвязывающие свойства тканевых белков после аллотрансплантации почки // Бюл. экспер. биол. и мед. 1991. № 9. С. 256.

4. Ермакова И.П., Потанина Т.В., Бузулина В.П. и др. Кинетические параметры связывания кальция тканевыми структурами при острой гиперкальциемии у человека // Физиология человека. 2012. Принята к публикации.

5. Левин А.Л., Андрианова М.Ю., Ермакова И.П. и др. Дифференцированные влияния pH, pCO2 и концентрации белка на уровень ионизированного кальция в плазме крови и алгоритм расчета его стандартизованного значения // Бюл. экспер. биол. и мед. 1986. № 12. С. 704.

6. Bailor C.H., Van Alstine H.E. The fate of intravenously administered calcium. Effects on urinary calcium and phosphorus fecal calcium and calcium-phosphorus balance // J. Сlin. Invest. 1950. Vol. 29. P. 1167.

7. Сlinical Disorders of Fluid and Electrolyte Metabolism / Eds. M.H. Maxwell, C.R. Kleeman. New York, 1980.

8. Copp D.H., Moghadam H., Mensen E.D. The Parathyroids and calcium metabolism // The Parathyroids / Eds. R.O. Greep, R.W. Talmage. New York, 1961. P. 203.

9. Evenepoel P. Calcium metabolism in the early post-transplant period // Minerva Urol Nefrol. 2011. Vol. 63 (1). P. 89–99.

10. Huang Y., Zhou Y., Castiblanco A. et al. Multiple Ca(2+)-binding sites in the extracellular domain of the Ca(2+)-sensing receptor corresponding to cooperative Ca(2+) response // Biochemistry. 2009. Vol. 48 (2). P. 388–398.

11. Kantham L., Quinn S.J., Egbuna O.I. et al. The calcium-sensing receptor (CaSR) defends against hypercalcemia independently of its regulation of parathyroid hormone secretion // Am J Physiol Endocrinol Metab. 2009. Vol. 297 (4). P. 915–923.

12. Kawarazaki H., Shibagaki Y., Fukumoto S. et al. Natural history of mineral and bone disorders after living-donor kidney transplantation: a one-year prospective observational study // Ther Apher Dial. 2011. Vol. 15 (5). P. 481.

13. McLean F.C., Hastings A.B. The state of calcium in the fluids of the body // J. Biol. Chem. 1935. Vol. 108. P. 285.

14. Messa P., Cafforio C., Alfieri C. Calcium and phosphate changes after renal transplantation // J Nephrol. 2010. Vol. 23 (Suppl 16). P. 175–181.

15. Surface and Interfacial Aspects of Biomedical Polimers / Ed. J.D. Andrade. New York, London, 1985. Vol. 2. P. 38.