Altered Membrane Fluidity Of Syncytiotrophoblast Of Preeclamptic Placentas Is Non-Dependent On Hif-1a

LEVI LORENA; PIEHL LILIANA; RUBÍN DE CELIS EMILIO; DAMIANO ALICIA E; STERIN-SPEZIALE NORMA

Los Cocos, Córdoba- Argentina

Simposio; III Latin-American Symposium on Maternal-Fetal Interaction and Placenta:Basic & Clinical Research; 2007

Placental Association of America

Preeclampsia is a pregnancy disorder characterized by abnormal trophoblast invasion giving rise to a hypoxic tissue with an increase of Hypoxia Inducible Factor-1alpha (HIF-1alpha). Alterations in plasma membrane composition affect membrane order, fluidity and lipid-protein interactions. Previously we observed an increase in sphingomyelin composition without changes in the apical membrane cholesterol amount of preeclamptic (PE) placentas. Here we determined if the membrane fluidity of syncytiotrophoblast (hST) is altered in PE placentas via HIF-1alpha. Methods: Placental explants were exposed to CoCl2 (a HIF-1a inducer) during 24 h. Vesicles from apical (MVM) and basal (BM) membranes from normal, PE and treated placentas were prepared by differential centrifugation. Lipids were extracted by Bligh-Dyer method, phospholipids separated by thin layer chromatography and quantified by Fiske-Subarrow. Cholesterol was determined by a commercial kit. Membrane fluidity was evaluated by the order parameter determined from the electron spin resonance spectra of the 5-doxylstearic acid insert into the membrane, using an X-band ESR Spectrometer Bruker ECS 106. Results: In explants treated with CoCl2, phosphatidylcholine concentration was similar to those found in normal placentas. However cholesterol levels were higher than control (n¼6, p