Rabbit beta-migrating very low density lipoprotein increases endothelial macromolecular transport without altering electrical resistance

Abstract

Rabbit aortic endothelial cells (RAEC) were grown on micropore filters in a new device. This system allowed in situ measurement of transendothelial electrical resistance (TEER). The monolayers demonstrated a TEER of 14 ± 1 Ω · cm2 at confluence. No difference was seen in the transport of low density lipoproteins (LDL) across endothelial cell monolayers obtained from normal or Watanabe heritable hyperlipidemic rabbits, indicating that the LDL receptor was not involved in the LDL transport. TEER was inversely correlated with 22Na transport (r2 = 0.93, P = <0.001) but not with 125I-LDL transport. The amount of LDL transported at 15° C or across glutaraldehyde-fixed monolayers was half that of the controls at 37°C. Preincubation of the monolayers with rabbit beta-migrating very low density lipoprotein (β-VLDL) increased cholesterol content by 65%, and the transport of albumin and LDL doubled without a change in TEER. Removal of β-VLDL from the culture medium resulted in the return of cellular cholesterol content and LDL transport to control values. We conclude that preincubation of RAEC with β-VLDL resulted in an increased permeability to LDL and albumin, and that β-VLDL may promote increased transendothelial transport of macromolecules in cholesterol-fed rabbits.