18 Ultrastructural Alterations of Placental Tissue After 6H of Hypoxic Dual in vitro Placenta Perfusion

Background: Peripartal asphyxia affects the foetus and the placenta with its functions. This can be studied by the dual in vitro placenta perfusion model enabling the separated ex vivo perfusion of maternal and foetal circulation and simulating asphyxia.Aim: Examination of placental villous ultrastructure by electron microscopy before and after 6h of dual in vitro placenta perfusion with defined hypoxia to study whether morphological alterations could indicate a loss of placental function.Methods: Placentae (n=20) after normal pregnancies were studied. Written informed consent was obtained. Villous tissue was sampled before and after 6h of normoxic (pO2 80–90mmHg, n=10) or hypoxic (pO2= 20–30mmHg, n=10) placenta perfusion. Fixation, embedding, preparation of semi- and ultrathin sections. Systematic investigation by electron microscopy of terminal villous syncytio- and cytotrophoblast with its substructures mitochondria, rough and smooth endoplasmatic reticulum (ER), nucleus, golgi-apparatus and microvilli. Glucose consumption, lactate production, creatinine and antipyrin permeability as well as leptin- and hCG-release were used as control parameters during perfusion.Results: Terminal villi of all examined placentae showed intact substructures before and after normoxic perfusion. After 6h of hypoxic placenta perfusion the terminal villi demonstrated morphological alterations: villous stroma was oedematous, cell organelles (mitochondria, ER) swollen or completely degenerated, syncytio- and cytotrophoblast interspersed with multiple vacuoles and microvilli slenderly extended or partly cut off. The foetal blood vessels appeared narrow with luminal orientated endothelial cells nuclei. The morphological results correlated with the functional data.Conclusion: 6h of hypoxic dual in vitro placenta perfusion induces degenerative alterations of terminal villi which may impair the placental barrier and placental function.