Membrane fluidity and oxygen diffusion in cholesterol‐enriched endothelial cells

Article type: Research Article

Authors: Dumas, Dominique^; | Latger, Véronique | Viriot, Marie‐Laure | Blondel, Walter | Stoltz, Jean‐François

Affiliations: Laboratoire d’Angiohématologie et Hémorhéologie, équipe LEMTA – UMR CNRS 7563 et équipe FR W0070 CNRS – UHP – INPL – CHU, Faculté de Médecine, F‐54505 Vandoeuvre‐lès‐Nancy, France | DCPR (GRAPP) – UMR CNRS 7530, ENSIC‐INPL, 1 rue Grandville, 54000 Nancy, France

Note: [] To whom correspondence should be addressed: Fax: +33 03 83 59 26 43; E‐mail: Dumas@hemato.u‐nancy.fr.

Abstract: In this study, we measured the influence of cholesterol rigidification on oxygen permeability in human endothelial cell monolayer membranes (ECs). Cholesterol‐induced membrane rigidification was assessed at different membrane depths by a fluorescence polarization method with diphenyl‐hexatriene (DPH) and 1‐(4‐trimethylamino)‐6‐phenylhexatriene (TMA‐DPH). Fluorescence quenching by oxygen was probed in preferentially labelled membrane with pyrene butyric acid (PyC_{4}) and pyrene dodecanoic acid (PyC_{12}), as shown with a 3D fluorescence microscope (CellScanTM System). With both probes the experiments revealed a decrease in oxygen diffusion as the cholesterol concentration increased in the medium culture (from 3.42 \muM to 17.11 \muM). We showed that very low concentrations of cholesterol (about 1000 times below normal value, 6.2 mM) particularly decrease oxygen levels or diffusion rate in the middle region of the membrane. In conclusion, these findings prove in a direct manner that cholesterol significantly affect the endothelial barrier function and molecular oxygen transfer to underlying tissues. Risk factors (cholesterol) directly would contribute to tissue ischemia.

Journal: Clinical Hemorheology and Microcirculation, vol. 21, no. 3-4, pp. 255-261, 1999