Activity and inhibition of elastase in GCF

The aim of this study was to investigate the presence of free elastase in GCF Samples were taken from inflamed sites in 12 subjects with gingivitis alone and from inflamed sites with and without tissue destruction in 19 patients having periodontitis. Elastase activity was measured with a low molecular weight substrate. To distinguish between free elastase and elastase bound to alpha-2-macroglobulin (A2MG), an excess of alpha-1-antitrypsin (A1AT) was added to the samples. The activity that could be inhibited by A1AT was considered as free elastase, and the uninhibited activity as derived from the elastase-A2MG complex. The elastase-A1AT complex was measured with an ELISA. Free elastase was found in almost all samples, but both the total amount and the proportion of free elastase were higher in samples from sites showing destruction. The elastase-A2MG complex was also increased in sites with tissue destruction, while there was no significant difference in the amount of A1AT complex between the 3 categories of sites. In conclusion, our study clearly reveals free elastase in GCF The elevated levels of free elastase in sites showing tissue destruction seem to be due to a combination of increased release of elastase and an inactivation of A1AT.