Esomeprazole reduced expression and secretion of the antiangiogenic factor, soluble fms-like tyrosine kinase-1 (sFLT-1) in cultured human placental cells. Esomeprazole magnesium hydrate (Eso MH) and esomeprazole magnesium trihydrate (Eso MTH) reduced secretion of sFLT-1 by primary cytotrophoblast cells (A). Both Eso MTH and Eso MH reduced primary cytotrophoblast mRNA expression of the sFLT-1 variants, sFLT1-e15a (B), and sFLT1-i13 (C). Secretion of sFLT-1 from HUVECs was reduced by treatment with esomeprazole MH only (D). There was no alteration in the relative mRNA expression of sFLT1-e15a (E) and sFLT1-i13 (F) in HUVECs, following treatment with either Eso MH or Eso MTH. Eso MH and Eso MTH were added at 100 μmol/L concentrations. Data expressed as mean ± SEM (n = 3). The statistical significance is indicated as follows: * p < 0.05, ** p < 0.01, **** p < 0.0001.