BACKGROUND: Calcifediol (25D) availability is crucial for calcitriol (1,25D) synthesis, but regulation of vitamin D hydroxylases is majorly responsible for 1,25D synthesis. The net efficiency of vitamin D hydroxylases might be informative. We assume that the ratio between calcitriol and calcifediol (25D/1,25D) serum concentrations could suggest the vitamin D hydroxylation efficiency. METHODS: We evaluated 25D/1,25D in different patient populations: hemodialysis (HD, n = 76), CKD stage 2-5 (n = 111), renal transplant (TX, n = 135), patients with no renal disease (No-CKD, n = 290), and primary hyperparathyroidism (PHP, n = 20). RESULTS: The geometric mean of 1,25D/25D (pg/ng) averaged 1.11 (HD), 1.36 (CKD), 1.77 (TX), 2.22 (No-CKD), and 4.11 (PHP), with a progressive increment from HD to PHP (p-value for the trend <0.001). Each clinical condition elicited a significant effect on 25D/1,25D (p < 0.0001) and adjusted multivariate analysis indicated levels of Cas, Ps, PTH, and 25D as predictors of 25D/1,25D. Both in vitamin D deficient and replete subjects (25D< or ≥20 ng/ml) 25D/1,25D associated with each clinical condition (p < 0.0001) and mean values increased progressively from HD to PHP (p-values for the trend <0.0001). Regression analysis between 25D (substrate) and 25D/1,25D (efficiency) revealed an exponential negative correlation in No-CKD (r(2)Exp = 0.53, p < 0.001) with sharp increments of 25D/1,25D when 25D values are <20 ng/ml. At variance, in CKD (r(2)lin = 0.19) and in TX (r(2)lin = 0.32) the regression was linear as if, in case of deficit, some inhibition of the system were operating. CONCLUSION AND GENERAL SIGNIFICANCE: In conclusion 1,25D/25D can reflect the efficiency of vitamin D hydroxylases more than separate evaluation of 25D and 1,25D and can facilitate the therapeutic choices in different patient populations.

Calcitriol/calcifediol ratio. an indicator of vitamin D hydroxylation efficiency / Marzia, Pasquali; Tartaglione, Lida; Rotondi, Silverio; Maria Luisa, Muci; Mandanici, Giusy; Farcomeni, Alessio; Martino, Marangella; Mazzaferro, Sandro. - In: BBA CLINICAL. - ISSN 2214-6474. - STAMPA. - 3:(2015), pp. 251-256. [10.1016/j.bbacli.2015.03.004]

Calcitriol/calcifediol ratio. an indicator of vitamin D hydroxylation efficiency

TARTAGLIONE, LIDA;ROTONDI, SILVERIO;MANDANICI, GIUSY;FARCOMENI, Alessio;MAZZAFERRO, SANDRO
Ultimo
2015

Abstract

BACKGROUND: Calcifediol (25D) availability is crucial for calcitriol (1,25D) synthesis, but regulation of vitamin D hydroxylases is majorly responsible for 1,25D synthesis. The net efficiency of vitamin D hydroxylases might be informative. We assume that the ratio between calcitriol and calcifediol (25D/1,25D) serum concentrations could suggest the vitamin D hydroxylation efficiency. METHODS: We evaluated 25D/1,25D in different patient populations: hemodialysis (HD, n = 76), CKD stage 2-5 (n = 111), renal transplant (TX, n = 135), patients with no renal disease (No-CKD, n = 290), and primary hyperparathyroidism (PHP, n = 20). RESULTS: The geometric mean of 1,25D/25D (pg/ng) averaged 1.11 (HD), 1.36 (CKD), 1.77 (TX), 2.22 (No-CKD), and 4.11 (PHP), with a progressive increment from HD to PHP (p-value for the trend <0.001). Each clinical condition elicited a significant effect on 25D/1,25D (p < 0.0001) and adjusted multivariate analysis indicated levels of Cas, Ps, PTH, and 25D as predictors of 25D/1,25D. Both in vitamin D deficient and replete subjects (25D< or ≥20 ng/ml) 25D/1,25D associated with each clinical condition (p < 0.0001) and mean values increased progressively from HD to PHP (p-values for the trend <0.0001). Regression analysis between 25D (substrate) and 25D/1,25D (efficiency) revealed an exponential negative correlation in No-CKD (r(2)Exp = 0.53, p < 0.001) with sharp increments of 25D/1,25D when 25D values are <20 ng/ml. At variance, in CKD (r(2)lin = 0.19) and in TX (r(2)lin = 0.32) the regression was linear as if, in case of deficit, some inhibition of the system were operating. CONCLUSION AND GENERAL SIGNIFICANCE: In conclusion 1,25D/25D can reflect the efficiency of vitamin D hydroxylases more than separate evaluation of 25D and 1,25D and can facilitate the therapeutic choices in different patient populations.
2015
vitamin D; vitamin D hydroxylation; calcitriol; calcifediol; chronic renal failure; renal transplantation
01 Pubblicazione su rivista::01a Articolo in rivista
Calcitriol/calcifediol ratio. an indicator of vitamin D hydroxylation efficiency / Marzia, Pasquali; Tartaglione, Lida; Rotondi, Silverio; Maria Luisa, Muci; Mandanici, Giusy; Farcomeni, Alessio; Martino, Marangella; Mazzaferro, Sandro. - In: BBA CLINICAL. - ISSN 2214-6474. - STAMPA. - 3:(2015), pp. 251-256. [10.1016/j.bbacli.2015.03.004]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/771372
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