Albumin modulation of paracellular permeability of pig vena caval endothelium shows specificity for pig albumin

Abstract

We measured endothelial hydraulic conductivity (Lp,e) and endothelial electrical resistance (Re) of pig vena cava in pig serum albumin (PSA) and bovine serum albumin (BSA) to determine whether specificity for the autologous albumin found in dog vena cava is a general property of mammalian endothelium. Pigs were anesthetized with pentobarbital sodium for surgical removal of the thoracic inferior vena cava. A vessel segment was placed as a membrane separating two compartments in a chamber. Vessels kept in 30 mg/ml BSA had Lp,e values of 1.30 +/- 0.81 x 10(-7) cm.s-1.cmH2O-1 (n = 9) and Re values of 13.8 +/- 2.6 omega.cm2 (n = 3). Vessels kept in PSA had Lp,e values of 0.257 +/- 0.125 x 10(-7) cm.s-1.cmH2O-1 (n = 5) and Re values of 21 +/- 6.3 omega.cm2 (n = 4). The differences between Lp,e and Re in BSA and PSA were statistically significant (P < 0.05). In vessels kept in PSA, switching to BSA caused a doubling of Lp,e. Lower Lp,e and higher Re in PSA as compared with those in BSA suggest that specificity for the autologous albumin is a general phenomenon in mammalian endothelium and that albumin binding to specific sites is associated with its permeability effect.