Urokinase-type plasminogen activator and plasminogen activator inhibitor antigen in tissue extracts of paranasal sinus mucous membranes affected by chronic sinusitis and antrochoanal polyps

We examined the effect of pH on the extraction of urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) from paranasal sinus mucous membrane associated with chronic sinusitis and antrochoanal polyps. The specific activity of u-PA extracted with buffer at pH 7.4 was stronger than that extracted with buffer at pH 4.2. The antigen level of u-PA extracted with the acidic buffer was significantly higher than that extracted with the neutral buffer. In contrast, the difference in antigen levels of PAI-1 extracted with the acidic buffer and neutral buffer was not significant. Based on these results, we inferred that the u-PA-PAI-1 complex was extracted by the acidic buffer and the activity of u-PA was therefore decreased.