“…Villous explants from term placentas have been used to evaluate villous metabolism, endocrine function and transport of amino acids and other small molecules [120][121][122] , whereas early placental tissue explants have been used to study placentation, invasion of EVTs, trophoblast proliferation and differentiation 123,124 . Villous explants from both early and term placenta have been used to study the effects of xenobiotics on transporter expression 125 and endoplasmic reticulum (ER) stress 126 . These models maintain the topology of chorionic villi (i.e., contain microvillous membrane of the syncytium, mesenchymal stromal cells, endothelial cells, blood cells and Hofbauer cells) and represent a functional unit of the placenta.…”