Objective      To determine the effect of albumin-bound indoxyl sulfate (IS) on the activity of chemotaxis in the monocytes and investigate its underlying potential mechanism.       Methods      Different concentrations of IS were bound to 4% human serum albumin (HAS)

and the binding efficiency was evaluated by high-performance liquid chromatography (HPLC). CCK-8 assay was employed to evaluate the proliferation of THP-1 cells after exposure to free IS and albumin-bound IS at different doses for 24 h. After free and albumin-bound IS were respectively incubated with THP-1 cells for 24 h

Transwell chemotaxis chamber was used to measure the chemotaxis

ELISA was employed to evaluate the contents of monocyte chemoattractant protein-1 (MCP-1)

and flow cytometry was adopted to detect the protein expression of chemokine receptor CCR2.       Results      The protein binding efficiency of albumin-bound IS was about 90%. Both free and albumin-bound IS suppressed the proliferation of THP-1 cells (P0.05)

and up-regulated the MCP-1 and CCR2 in THP-1 cells in a dose-dependent manner (P0.05).       Conclusion      Albumin-bound IS

like free one

enhances the chemotaxis of monocytes by up-regulating the expression of MCP-1 and CCR2. Eliminating albumin binding IS is beneficial to reduce cardiovascular events

inflammation

and infection-related complications in uremic patients.