Using Cotyledon Perfusion to Study Drugs Transfer Across the Placenta

Ex Vivo Study of Drugs Transfer Across the Placenta

Drug prescriptions are usual during pregnancy however women and their fetuses still remain an orphan population with regard to drugs efficacy and safety clinical studies. Most xenobiotics diffuse through the placenta and some of them can alter fetus development resulting in structural abnormalities, growth or functional deficiencies. The aim of the study is to study the drug transfer using human placenta after delivery.

For ethical reasons, pregnant woman are not included in clinical trials so that data regarding safety and efficacy of many drugs are scarce. It is known that xenobiotics across the placental barrier but studies regarding quantity and mechanisms of this transfer remain insuffisant. Among the different methodologies to evaluate drug transfer, perfusion of human cotyledon is one of the most relevant ones. The two sides of the cotyledon, fetal and maternal ones, are perfused within the hour after delivery with EARLE medium in a double closed circuit. The studied drug (it can be any drug given to pregnant mothers) and antipyrine (the control molecule) are added at the beginning of the three hours perfusion realized at 37°C, with maternal flow rate of 12ml/min and fetal one of 6ml/min. Samples are collected along the perfusion and the drugs dosage will be done in the pharmacology department of Cochin Hospital. Tissues of the cotyledon will be also collected to study the proteins, and ARNs expressed. The drug concentrations will be analyzed by calculating fetal to maternal concentrations ratios and a fetal transfer rate (fetal drug quantity on total drug quantity at the end of the perfusion). Then modelling on Monolix software will be done to estimate the transfer constants across the two compartments. Modelling will allow to estimate the interindividual variability and to test covariables like sex, gestation duration, genetics, or protein expression. Proteins will be studied by an appropriated method (western blot, or proteomic analysis). The genetics study will consist in candidate gene approach. Polymorphisms will be chosen in genes coding for transporters or enzymes or their regulators.

Inclusion Criteria:

• pregnant women older than 18 years,
• patient with social security or health insurance,
• from the 24th week of amenorrhea,
• patient who has given her consent,

Exclusion Criteria:

• Maternal pathologies pre-existing pregnancy :

  • diabetes-like vascular disease,
  • arterial hypertension,
  • known prothrombotic pathology, history of venous thrombosis or pulmonary embolism,
  • maternal serology HIV+, BHV+, CHV+ and syphilis,

• Pregnancy and fetal pathologies :

  • pre-eclampsia,
  • delayed growth in utero (can affect placental circulation),
  • gestational diabetes without insulin,
  • fetal malformation,
  • known genetic pathology,

• Patient under tutorship or curatorship, or not speaking french,

• Patient who has not given her consent