Assessment of an in vitro transport model using BeWo b30 cells to predict placental transfer of compounds.

The human ex vivo placental perfusion model has regularly been used to study the transplacental transport of compounds. However, this method is laborious and dependent on the presence of fresh human placenta, hampering its use for the assessment of large numbers of compounds. An in vitro model for the placental barrier using BeWo b30 cells may provide an alternative to the ex vivo system. The present study aims to assess whether such an in vitro model could be used to reliably predict placental transfer. To this end, BeWo b30 cells, derived from a human choriocarcinoma, were grown on transwell insert to form a cell layer, separating an apical maternal compartment from a basolateral fetal compartment. For a set of nine selected model compounds, including the reference compound antipyrine, the transport velocity from the apical to the basolateral compartment was determined. Relative transport rates obtained were compared with the transfer indices (a measure for the transport relative to antipyrine) of these compounds obtained in ex vivo placental perfusion studies as reported in the literature. The relative transport rates in the in vitro BeWo model were in good correlation (R² = 0.95) with the transfer indices reported for the ex vivo model. This indicates that the BeWo model could be a valuable in vitro model for prediction of placental transfer of compounds.