Inhibition of human platelet cathepsin A by non-steroidal anti-inflammatory drugs--in vitro study.

Since the lysosomal proteases appear at site of inflammation they may be a target for non-steroidal anti-inflammatory drugs (NSAIDs). In in vitro study the inhibition of human platelet cathepsin A by NSAIDs was found. Indomethacin, phenacetin and aminophenazone were the most potent inhibitors of cathepsin A. Acetylsalicylic acid added to platelet lysate inhibited cathepsin A in the same extent as salicylate. The inhibition was time-dependent and reversed after dialysis. Mixed type of inhibition by salicylate was shown.