Conclusions
High-dose cholecalciferol decreased serum MCP-1 concentrations by 12 weeks in patients with early CKD, although the decrease was not maintained for the remainder of the year. In vitro results confirm an MCP-1-lowering effect of vitamin D. Future studies should determine if vitamin D-mediated reductions in MCP-1 concentrations reflect improved clinical outcomes.
Methods
In this double-blind, randomized, placebo-controlled trial, 46 subjects with early CKD (stages 2 and 3) were supplemented with oral cholecalciferol (50 000 IU weekly for 12 weeks followed by 50 000 IU every other week for 40 weeks) or a matching placebo for 1 year. Serum tumor necrosis factor-α, interleukin-6, monocyte chemoattractant protein-1 (MCP-1), interferon gamma-induced protein-10 and neutrophil gelatinase-associated lipocalin were measured at baseline, 12 weeks and 1 year. Serum cathelicidin (LL-37) was measured at baseline and 12 weeks. An in vitro experiment was performed to investigate the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) treatment on MCP-1 secretion in THP-1 monocytes activated with lipopolysaccharide (LPS) and Pseudomonas aeruginosa.
Results
By 12 weeks, serum MCP-1 decreased in the cholecalciferol group (66.2±2.5 to 60.8±2.6 pg/ml, group-by-time interaction P=0.02) but was not different from baseline at 1 year. Other markers of inflammation and immunity did not change. In vitro, LPS- and Pseudomonas-activated monocytes treated with 1,25(OH)2D3 had significantly less MCP-1 secretion compared with untreated cells. Conclusions: High-dose cholecalciferol decreased serum MCP-1 concentrations by 12 weeks in patients with early CKD, although the decrease was not maintained for the remainder of the year. In vitro results confirm an MCP-1-lowering effect of vitamin D. Future studies should determine if vitamin D-mediated reductions in MCP-1 concentrations reflect improved clinical outcomes.