PERMSELECTIVITY OF CULTURED ENDOTHELIAL MONOLAYERS: EFFECT OF SIZE AND CHARGE OF THE TRANSPORTED MOLECULES

Known molecular size neutral dextrans (molecular weight (MW) range ∼6,000-∼500,000), anionic (dextran sulfate, ∼500,000 MW), and cationic (DEAE-dextran, ∼500,000 MW) were used to determine the permselectivity characteristics of bovine pulmonary arterial endothelial monolayers. The experimental system consisted of two compartments separated by a gelatinized polycarbonate membrane (0.8 μm pore size) on one side of which endothelial monolayers were grown to confluence. Dextran solutions (1 gram %) were prepared in phosphate buffered saline buffer (containing 0.5 gram % serum albumin) and placed on the luminal side. Transendothelial dextran transport at 37°C was studied as a function of time. Dextran concentrations were determined spectrophotometrically using the anthrone method. The results (mean ± S.E.) of the dextran concentrations in the abluminal compartment at 45 minutes are given in the table.The endothelial monolayers markedly restricted dextran transport compared to transport across gelatinized, polycarbonate membranes alone (controls). Furthermore, the results indicate that size and charge of the transported molecules determine the sieving mechanism responsible for their passage across the cultured endothelial monolayer. (Supported by HL32418.)