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

The incidence of infectious diseases increases with ageing. The enzymatic activity of leucocytes may have a relevant role in the morbidity and mortality due to infections in the elderly. In this study we have compared the activity of enzymes involved in the inflammatory response in leucocytes from young and elderly women. A total of 35 healthy females was studied, 20 volunteers aged 78-98 years (mean 89.1 years) and 15 young controls aged 19-34 years (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 substrates employed were for oxidative burst, L-aminopeptidase, collagenase, cathepsin B, C, D and, G and dipeptidyl peptidase I. The intracellular enzyme activity assessed by flow cytometry in leucocytes from young and elderly women was similar, as far as oxidative burst, L-aminopeptidase, cathepsin B, C, D and G are concerned. An increased collagenase activity was detected in 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 was 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, respectively (P = 0. 0036). The proper functional activity of intracellular enzymes involved in inflammatory responses is likely to be determinant for successful ageing.

[Cathepsin L-like activity in hemolymph of females crammed with Boophilus microplus]. / Actividad semejante a catepsina L en la hemolinfa de hembras repletas de Boophilus microplus.

The cysteine-proteinase activity present in the hemolymph of females crammed with Boophilus microplus at the second oviposition was proved. The enzyme assay was performed using the synthetic N-carbobenzoxi-phenilalanyl-arginil-4-metoxibetan++ +-naphthylamide substrate, and hydrolysis in both raw ovarim extract and hemolymph were observed. The activity was 100% inhibited by trans-epoxisuscinyl-L-leucidamide (4-guadinine) butane, an specific inhibitor for cysteine-proteinase. Polyacrylamide and gelatin-gel electrophoresis showed the existence of only one active band in both samples tested with the same electrophoretic sliding (approximately 38 kDa).