Trypsin, elastase, plasmin and MMP-9 activity in the serum during the human ageing process

Objective: the aim of this work was to define the influence of the ageing process on the activity of proteolytic enzymes, such as trypsin, elastase, plasmin and active MMP-9 concentration, as well as the inhibitor alpha 1-antitrypsin. Moreover, we assessed associations between enzyme activity and selected clinical and biochemical parameters. Methods: healthy normotensive volunteers (n=60, 30 women) aged 20-82years were split into subgroups: young (aged 20-22), middle-aged (49-52) and elderly (77-82). Serum enzyme activity was assessed using fluorometric methods. Results: overall, active MMP-9 concentration and trypsin activity decreased with age, and alpha 1-antitrypsin concentration and plasmin activity increased. Activity of elastase increased with age when compared to the young age group. An inverse correlation was identified between MMP-9 concentration and BMI and a direct correlation found between BMI and elastase, plasmin activity and 1-antitrypsin concentration. In the middle-aged group, glucose correlated directly with trypsin activity and inversely with MMP-9 concentration. Trypsin activity and MMP-9 concentration correlated inversely with cholesterol concentration and plasmin and elastase activity, and the 1-antitrypsin concentration correlated with cholesterol concentration in the overall group. Conclusions: the results confirm the influence of the ageing process on the activity of serum proteolytic enzymes. The activity of individual proteolytic enzymes in the serum changes with age.