Increased collagenase and dipeptidyl peptidase I activity in leucocytes from healthy elderly people

The incidence of infectious diseases increases with ageing. The enzymatic a ctivity of leucocytes may have a relevant role in the morbidity and mortali ty due to infections in the elderly. In this study we have compared the act ivity of enzymes involved in the inflammatory response in leucocytes from y oung and elderly women. A total of 35 healthy females was studied, 20 volun teers aged 78-98 years (mean 89.1 years) and 15 young controls aged 19-34 y ears (mean 26 years). All of them were in good clinical condition, without any acute or chronic disease. Intracellular enzyme activity was analysed by flow cytometry in leucocytes from young and elderly women. The enzyme subs trates employed were for oxidative burst, L-aminopeptidase, collagenase, ca thepsin B, C, D and, G and dipeptidyl peptidase I. The intracellular enzyme activity assessed by flow cytometry in leucocytes from young and elderly w omen was similar, as far as oxidative burst, L-aminopeptidase, cathepsin B, C, D and G are concerned. An increased collagenase activity was detected i n granulocytes from elders. The mean fluorescence channels for this enzyme corresponded to 86 +/- 23 and 60 +/- 15 in cells from elders and controls, respectively (P = 0.01224). An increased dipeptidyl peptidase I activity wa s detected in lymphocytes from elderly women. The corresponding values for this enzyme in elders and the young were 65.9 +/- 43.3 and 17.3 +/- 5, resp ectively (P = 0.0036). The proper functional activity of intracellular enzy mes involved in inflammatory responses is likely to be determinant for succ essful ageing.