Abstract
Vascular damage is the occasional manifestations in patients with rheumatoid arthritis (RA) . Using human endothelial cells (EC) as an in-vitro model of vascular tissue, we have examined the injurious effects of polymorphnuclear leucocytes (PMN) from RA patients on EC to investigate the role of PMN on vascular damge in RA. The results obtained are as follows.
(1) The mechanism of EC injury by PMN seemed to be via a non-lytic cell detachment rather than cell death, and there was no difference of injurious capacity between RA-PMN and normal-PMN.
(2) EC injury by PMN was partially inhibited by H2O2 scavenger, catalase, but was most prominently inhibited by simultaneous addition of catalase and protease inhibitor, suggesting that both H2O2 and protease have an injurious effect.
(3) EC injury by PMN and commercially available H2O2 was markedly inhibited by the addition of human serum in advance. The inhibitory effect of normal serum was much stronger than RA serum.
(4) At lower PMN/EC ratio, PMN enhanced the growth of EC, suggesting that PMN release injuryous factors as well as growth-stimulating factor.
