Possible role of plasminogen activator inhibitor-1 in bronchial asthma

ABSTRACT

Asthma represents a chronic inflammatory process of the airways. The plasminogen activator inhibitor-1 gene [PAI-1] has an essential role in promoting fibrosis after inflammation. The tissue-type plasminogen activator [t-PA] and urokinasc type plasminogen activator [u-PA] convert plasminogen to plasmin, which enhance proteolytic degradation of the extracellular matrix [ECM]. Among the inhibitors of plasminogen activators, PAI-1 is the most important in the process of lung fibrosis. The main role in the inhibition of fibrinolysis through the blockade of activators is ascribed to PAI-1. It is synthesized in endothelium, megakaryocytes, smooth muscle cells of vessels, and in the liver, with the help of cytokines, growth factors, cyclic nucleotides. hormones including glycocorticosteriods and bacterial endotoxins. The study is designed to investigate the correlation between plasma PAI-1 and bronchial asthma severity and whether steroid medications could affect its levels. The study included 40 children with bronchial asthma and 20 healthy children as control subjects. Estimation of plasma PAI-1 carried out for them using ELISA technique. There was a significant lowering of PAI-1 in all asthmatic groups in comparison to control group. The moderate asthmatic subgroups showed highly significant difference in comparison to mild asthmatic and to control group. The mild subgroups showed also significant difference to control group but with lesser mean value compared to moderate subgroups. The results suggest that PAI-1 may play an important role in the pathogenesis of bronchial asthma