Cigarette smoking alters sialylation in the Fallopian tube of women, with implications for the pathogenesis of ectopic pregnancy

SUMMARY Sialylation creates a negative charge on the cell surface that can interfere with blastocyst implantation. For example, α2,6‐sialylation on terminal galactose, catalyzed by the sialyltransferase ST6GAL1, inhibits the binding of galectin‐1, a β‐galactoside‐binding lectin. We recently reported the potential involvement of galectin‐1 and ‐3 in the pathogenesis of tubal ectopic pregnancy; however, the precise role of galectins and their ligand glycoconjugates remain unclear. Here, we investigated the expression of the genes encoding α2,3‐ and α2,6‐galactoside sialyltransferases (ST3GAL1−6 and ST6GAL1−2) and the localization of sialic acids in the Fallopian tube of women with or without ectopic implantation. ST6GAL1 expression was higher in the mid‐secretory phase than the proliferative phase of non‐pregnant women (P