The rtPA has been used extensively for cardiovascular disease to lyse preformed clots. However the dosage used (100mg) for the treatment of the myocardial infarction results cerebrovascular accidents in 9% of patients treated. The tPA therapy with much lower dosage (3 mg bid) dose for 2 weeks duration was found to be effective in restoring hearing in certain hearing loss patients. (R. Mora et al Annals Oto Rhino Laryn, in press). The specific aim of this study is to examine the effect of tPA on inflammatory cascades.

We have added Actlyse (rtPA) in graded concentration to 80% confluent monolayers of A549 (human lung epithelial cells – obtained from ATCC) in a 24 well plate. They were then incubated at 37°C (5% C0₂). The cells were harvested after 24 hours. Total RNA was isolated and reversed transcribed using oligo dT and AMV Reverse Transcriptase. The CDNAs for house keeping gene GAPDH, Chemokines, MMP-1 (matrix collagen degrading enzymes) were amplified IL-1⍺, IL-6, cxc chemokine IL-8 (a potent angiogenic factor and neutrophil chemattractant).

We observed a significant increase in steady state mRNA level of IL-8 and mmp-1 in tPA treated human lung epithelial cell line, in a concentration dependent manner.

These results indicate that the pathophysiologic effects pf tPA are mediated through regulating inflammatory cascade.