Effect of various blood-derived and semisynthetic nutrient media on in vitro uptake of 125I-albumin across the intact porcine aortic endothelial surface in an organ-support system.

Abstract

The effects on porcine arterial structure and permeability of a 4-hour in vitro incubation at 37 degrees C in eight different blood-derived and synthetic nutrient media were examined. Changes in arterial permeability were inferred from the normalized, 1-hour, pressurized, transendothelial uptake (M/c0 cm) of porcine 125I-albumin in 60 porcine aortic tissue preparations using an organ-support system. The organ-support system provided experimental control of ambient gas composition, temperature, transmural pressure, flow (stirring), and nutrient media at a number of sites along the vessel. Light and electron microscopic (scanning and transmission) structural correlations with the observed permeability changes were examined. The M/c0 from the autogenous serum (AS) medium was used as the "control" measurement in each vessel preparation. (Grand mean M/c0 for AS from all studies was 0.312 +/- 0.011 [x10(-3)] [mean +/- SEM] cm, n = 60.) For brevity, M/c0 values from the other media are expressed below as a percentage of the corresponding paired M/c0 from the AS. Uptake from heparinized autogenous blood was 113 +/- 9% of that from AS (p = 0.119); from heparinized autogenous plasma was 135 +/- 10% (p = 0.048); from AS+heparin was 97 +/- 5% (p = 0.498); from pooled porcine serum was 113 +/- 9% (p = 0.037); from a synthetic medium was 131 +/- 8% (p = 0.004); and from a physiological hetastarch solution was 532 +/- 8% (p = 0.0002). Associated light microscopic structural changes and ultrastructural changes were not found. We conclude that 1) incubation with AS and heparinized blood (both of which are autogenous blood substances containing platelet products or platelets) provided the best support for the endothelial barrier function, whereas heparin plasma, pooled serum, a synthetic medium, and particularly hetastarch provided poorer support; 2) arterial permeability can increase significantly without discernible endothelial ultrastructural changes; and 3) AS and to a lesser extent heparin blood should provide a suitable nutrient medium for short-term (less than 4-hour) metabolic support of the endothelial surface and subjacent tissues.