Plasma renin-angiotensin system-regulating aminopeptidase activities are modified in early stage Alzheimer's disease and show gender differences but are not related to apolipoprotein E genotype.

Alterations in blood pressure and components of the renin-angiotensin system (RAS) contribute to the development and progression of Alzheimer's disease (AD), resulting in changes that can lead or contribute to cognitive decline. Aspartyl aminopeptidase (ASAP), aminopeptidase A (APA), aminopeptidase N (APN) and aminopeptidase B (APB) catabolise circulating angiotensins, whereas insulin-regulated aminopeptidase (IRAP) has been described as the AT4 receptor. We have found in AD patients a significant decrease of APA activity in men but not in women, and of APN, APB and IRAP in both genders, when compared with control subjects.

Renin-angiotensin system-regulating aminopeptidases in tumor growth of rat C6 gliomas implanted at the subcutaneous region.

Background: Angiotensin peptides play roles in brain tumor infiltration and associated angiogenesis.

Materials And Methods: We explored the roles of soluble and membrane-bound forms of renin-angiotensin system-regulating aminopeptidase N (APN)-, aminopeptidase B (APB)-, glutamate aminopeptidase- and aspartate aminopeptidase (AspAP)-specific activities on tumor growth in the rat C6 glioma model with implantation into the subcutaneous abdomen of Wistar rats, evaluating these activities as biological markers. The tumor volume was assessed for three weeks and a sample of tumor was obtained every seven days to obtain the soluble and membrane-bound fraction, in order to assay enzyme activities fluorometrically using their corresponding aminoacyl-β-naphthylamide as substrates.