What are the effects of the eotaxin group of chemokines (CCL11, CCL24 and CCL26) on extravillous trophoblast (EVT) functions important during uterine decidual vessel remodelling?CCL11, CCL24 and CCL26 can regulate EVT migration, invasion and adhesion, highlighting a potential regulatory role for these chemokines during uterine decidual spiral arteriole remodelling in the first trimester of human pregnancy.A successful human pregnancy depends on adequate remodelling of the uterine decidual spiral arterioles, a process carried out by EVT which invade from the placenta. The invasion by EVT into the maternal uterine decidual vessels is regulated by the interaction of many factors including members of the chemokine subfamily of cytokines.This study used the HTR8/SVneo cell line as a model for invasive EVT. All experiments were repeated on at least three separate occasions.The effect of recombinant human CCL11, CCL24 and CCL26 on EVT migration and invasive potential was measured using the xCELLigence real-time system, wound-healing and Matrigel invasion assays, zymography to measure MMP activity and reverse zymography to measure TIMP activity. A commercially available adhesion assay was used to assess EVT adhesion to extracellular matrix proteins.All the three eotaxins were found to significantly stimulate migration of the EVT-derived cell line HTR8/SVneo (P 0.05). All the three eotaxins significantly increased HTR8/SVneo invasion (P 0.05). All the three eotaxins significantly increased HTR8/SVneo cell binding to collagen IV (P < 0.05) and fibronectin (P < 0.05).This work has been conducted in vitro with a commonly used cell line model of EVT, HTR8/SVneo.This study is the first to comprehensively examine the effects of the eotaxin group of chemokines on EVT functions and demonstrates that all the three eotaxins have the ability to regulate EVT functions critical to their role in vessel remodelling. This identifies a new role for the eotaxin group of chemokines during placentation.