Efeito da vitamina 25 (OH) D3 sobre a expressão de receptor toll-like (TLR-4) e mediadores inflamatórios sobre células endoteliais (HUVEC) no ambiente urêmico

Abstract

INTRODUCTION: The main cause of mortality in patients with chronic kidney disease (CKD) are Cardiovascular Diseases (CVD); associated with inflammatory mechanisms, which result in endothelial dysfunction and injury. A deficiency of 25 (OH)D3 and/or 1,25(OH)2D3 together with uremic environment may be responsible by poor outcome and activation of the Toll-like receptors (TLR). Furthermore, it is known that 1,25(OH)2D3 exerts immunomodulatory function in various cell types; however it is unclear whether supplementation with 25(OH)D3 might modulate inflammatory response in endothelial cells against uremic environment. OBJECTIVE: The aim of this study was to evaluate the effect of 25(OH)D3 on the expression of inflammatory markers and intracellular Vitamin D mechanism in endothelial cells against the uremic environment. MATERIALS AND METHODS: Endothelial cells from human umbilical cord (HUVEC) were incubated in the presence or absence of uremic serum treated or not treated with 25(OH)D3 for 24h. After incubation, we investigated the inflammatory mediators: Toll-like (TLR-4), ICAM-I (CD54), HLA-DR, Oxidative Stress (ROS) and intracellular mechanisms of Vitamin D Receptor (VDR), 1 -alphahydroxylase (CYP27) and 24-hydroxylase (CYP24) by flow cytometry. RESULTS: The uremic serum induced lower expression of TLR-4 compared with the healthy serum HUVEC. Treatment with 25(OH)D3 had no effect on the modulation of TLR-4 in these cells. For production of ROS, as expected, there was a higher expression in HUVEC stimulated with uremic serum. However, the treatment with 25(OH)D3 not decreased ROS production in these cells. We did not observe differences in the expression of VDR, CYP24 and CYP27 in any groups. We observe a positive correlation between IL-10, MCP-1 and ROS and cathelicidin, IL-10, TNFa and MCP1. There was a negative correlation between TLR-4 and ROS DISCUSSION: This study showed that the uremic serum induced a lower expression of TLR-4, higher expression of cytokines and ROS. Unfortunately, the treatment with 25(OH)D3 was not sufficient to diminish these inflammation mechanisms in HUVEC. Thus, it is necessary future studies to evaluate the impact of time response from 25(OH)D3 or 1,25(OH)2D3 in HUVEC in uremic model.