PROINFLAMMATORY ACTIVITY ON RAT CAROTID ENDOTHELIUM OF ALBUMINS OBTAINED BY DIFFERENT PROCEDURES

To investigate whether the proinflammatory activity of intravenously a dministered albumins is related to their preparation method, we compar ed bovine albumins obtained by alcohol precipitation and by heat shock . This last procedure produced a notable increase in monocyte adhesion /mm(2) in rat carotid endothelium (48+/-31, n=32 rats, vs 7+/-6, n=24 rats, mean+/-S.D., P<0.001). We found no changes in fluorescence emiss ion in these two groups, and no correlation was observed between leuko cyte adhesion and the contents of free fatty acids, free -SH groups, f ructosamine, dimers and polymers. The inhibition profile of the proinf lammatory activity by polyanionic molecules (fucoidan and dextran sulf ate 500 kD) was compatible with the recognition of heat-shocked albumi ns by scavenger receptors. Thiol disulfide exchange in albumins was pr oduced by ageing with cysteine and by incubation with protein disulfid e isomerase. Albumins thus modified increased the adhesion of leukocyt es to the endothelium, which indicates that some isomeric forms of alb umin generated by thiol disulfide exchange may acquire proinflammatory behavior. (C) 1997 Elsevier Science Ltd.