Background:The wall of an abdominal aorta aneurysm shows increased activity of metalloproteinases, aspartyl cathepsins and cystein cathepsins, and decreased activity of inhibitors of these enzymes, as compared to the wall of a normal aorta. Parietal thrombi of the aneurysm also show marked proteolytic activity. The aim of our study was to determine the activity of secretory enzymes, membrane enzymes, cytosol enzymes, mitochondrial enzymes and lysosomal enzymes in the blood plasma of patients with abdominal aortic aneurysm.Material/Methods:Blood for examinations was collected from 15 patients with abdominal aorta aneurysm without coexisting diseases, and from the same number of healthy subjects, to determine the activity of lactic acid dehydrogenase (LDH), 5’ nucleotidase (5’NT), gamma-glutamyltranspeptidase (GGTP) and cholinesterase (ChE), alanine aminotransferase (ALT), aspartic aminotransferase (AST), cathepsin B (CB), cathepsin D (CD), and cathepsin L (CL).Results:The plasma activity of ALT, AST and GGTP in the blood of patients with aortic aneurysm is lower than in the plasma of healthy subjects. The activity of LDH, 5’NT and ChE, CB and CL does not significantly differ in the plasma of patients with aortic aneurym compared to the plasma of healthy subjects. The activity of CD is increased in the plasma of patients with aortic aneurysm.Conclusions:Determination of cathepsin D activity may be helpful in the diagnosis of aortic aneurysm.

Keywords: Alanine Transaminase - blood, Aortic Aneurysm - blood, Aortic Aneurysm - enzymology, Aspartate Aminotransferases - blood, Cathepsins - blood, Enzymes - blood, Lymphocytes - enzymology, Metalloproteases - blood, Subcellular Fractions - enzymology, Alanine Transaminase - blood, Aortic Aneurysm - enzymology, Aspartate Aminotransferases - blood, Cathepsins - blood, Enzyme Inhibitors - blood, Enzymes - blood, Lymphocytes - enzymology, Metalloproteases - blood, Neutrophils - enzymology, Reference Values, Subcellular Fractions - enzymology, gamma-Glutamyltransferase - blood