Calcitriol counteracts endothelial cell pro-inflammatory processes in a chronic kidney disease-like environment

J Steroid Biochem Mol Biol 124(1-2):6 (2011) PMID 21236342

In advanced chronic kidney disease (CKD), hypocalcemia, high levels of advanced glycation end products (AGEs), and parathyroid hormone (PTH) coexist and are considered to play a role in the development of chronic vasculopathies. The aim of the present study was to evaluate the impact of a CKD-like environment on cultured endothelial cell (EC) functions and to assess the impact of calcitriol on the expression of parameters such as endothelial nitric oxide synthase (eNOS), receptor of AGEs (RAGE), interleukin 6 (IL-6) and nuclear factor kappa B (NF@kB). Human umbilical vein cord endothelial cells (HUVEC) were grown in medium containing low Ca^2^+ concentration stimulated with AGE-HSA and PTH and treated with calcitriol for additional incubation. mRNA expression was established by reverse transcriptase-PCR, protein expression by Western blot analysis, IL-6 secretion by ELISA, NOS activity by conversion of [^1^4C]arginine to [^1^4C]citrulline and DNA-binding activity of NF@kB-p65 assayed colorimetrically in nuclear extracts. The CKD-like environment characterized by the association of low Ca^2^+ and high levels of AGEs and PTH, depressed eNOS system activity and enhanced RAGE and IL-6 expression/secretion. DNA-binding activity of nuclear NF@kB-p65 was increased and the expression of I@kB@a decreased. Addition of calcitriol normalized the expression, secretion and activity of eNOS, RAGE and IL-6. The enhanced NF@kB activity was also counteracted probably due to the increased I@kB@a expression. The effect of CKD-like environment on EC may partly explain the increased vasculopathies in CKD patients, in contrast to calcitriol, which suggests a vascular protective action.

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