Construction of a human placental brush border membrane vesicle model for evaluating the effect of antenatal drugs on OCTN1/2 transport function.

Organic cation transporters novel 1 and 2 (OCTN1/2) localize specifically to the brush border membrane of human placentas, where they facilitate transmembrane delivery of vital substrates including ergothioneine and L-carnitine to sustain placental antioxidant balance and fetal energy metabolism. Multidrug regimens are frequently administered to manage gestational complications, yet these therapeutics may unintentionally impair placental OCTN1/2 activity and perturb bidirectional maternal-fetal nutrient trafficking. Herein, we established and fully validated a human placental brush border membrane vesicle (BBMV) model. Morphological and biochemical characterization confirmed structural integrity, high purity, and a predominantly right-side-out orientation (ROV), with stable OCTN1/2 expression. Substrate uptake experiments with ergothioneine and L-carnitine revealed classical saturable concentration-dependent kinetics, which were substantially suppressed by verapamil. This validated BBMV model was applied to assess the modulatory actions of 11 widely prescribed antenatal medicines on OCTN1/2 transport function. Most antidiabetic, antihypertensive, and tocolytic drugs exhibited minimal impact on OCTN1. However, metformin, glibenclamide, and labetalol moderately inhibited OCTN2, which could hinder placental L-carnitine uptake. Notably, fluoxetine exerted inhibitory effects on both OCTN1 and OCTN2, implying elevated risks of impaired placental antioxidant defense and energy substrate transfer. These findings elucidate the transport characteristics of placental OCTN1/2 and identify unintended inhibitory effects of common antenatal drugs, providing critical experimental references for rational clinical medication during pregnancy.