Proteolytic enzyme activity as a result of aging

Abstract

The extracellular matrix (ECM) undergoes constant dynamic changes; proteolytic enzymes, particularly the serine proteases plasmin, trypsin and elastase, catalyze critical functions in these processes. Notably, ECM degradation disorders have been reported in various morbid conditions, including cardiac infarction, atheromatosis, and neoplastic diseases, indicating a physiological requirement for proper ECM maintenance. Here we define the role of proteolytic enzymes in the development of aging by assessing changes in proteolytic enzyme activity in serum during aging in rats. The activities of trypsin, elastase and plasmin in rat serum were determined by the fluorometric method using AMC-labeled substrates in 34Wistar rats divided into four age groups: 3 month-olds (n=8), 9 month-olds (n=8), 15 month-olds (n=8) and 24 month-olds (n=10). Analysis of proteolytic enzyme activity in four age-dependent groups revealed that in comparison to their 3, 9, and 24 month-old counterparts, the 15 month-old rats exhibited a statistically significant increase in average elastase activity. In accordance with previous studies, a statistically significant increase in trypsin levels was found in the 3 month-old rats, suggesting that trypsin activity decreases with age. Average plasma plasmin activity in the 24 month-old rats was, moreover, statistically significantly higher than that in the other three age groups. Analysis of combined proteolytic activity indicates that age-dependent patterning of blood serine protease enzyme activity may be related to age-related diseases.