This study aimed to screen out serum special proteins and seek interaction between them, which would provide new therapeutic targets and elucidate the comprehensive pathophysiological mechanism for EH. Evidence is accumulating that the local ocular RAAS is involved in aqueous humor dynamics, regulation of intraocular pressure, neuroprotection and ocular pathology making components of RAAS attractive candidates when developing new effective ways to treat glaucoma.Įssential hypertension (EH) is a risk factor for some severe diseases.Components of renin-angiotensin-aldosterone system have been detected in different structures of the human eye, introducing the concept of a local intraocular renin-angiotensin-aldosterone system (RAAS).This review focuses on the local ocular RAAS in the anterior part of the eye, its possible role in aqueous humor dynamics and intraocular pressure as well as RAAS as a potential target for anti-glaucomatous drugs.
A local RAAS and its components have been detected in many structures of the human eye. These local regulatory systems, such as the one present in the vascular endothelium, are responsible for long-term regional changes. In addition to the systemic RAAS, tissue-specific regulatory systems have been described in various organs, evidence that RAAS is both an endocrine and an autocrine system. The first mentioned axis is known to counterbalance the deleterious effects of the latter axis. In its entirety, RAAS comprises dozens of angiotensin peptides, peptidases and seven receptors. Angiotensin II, angiotensin converting enzyme 1 and angiotensin II type 1 receptor (ACE1–AngII–AT1R). Angiotensin (1–7), angiotensin converting enzyme 2 and Mas receptor (ACE2–Ang(1–7)–MasR), 2. When aldosterone is included, RAAS is involved also in fluid and electrolyte homeostasis. The renin-angiotensin system (RAS) is one of the oldest and most extensively studied human peptide cascades, well-known for its role in regulating blood pressure. Thus, the angiotensin II-generating protease of human neutrophils has been identified as cathepsin G on the basis of subcellular localization, substrate specificity, physicochemical characteristics, and antigenic identity.
Individually purified angiotensin II-generating protease and cathepsin G had similar proteolytic and esterolytic activity for angiotensinogen and N-benzoyl-L-tyrosine ethyl ester on a weight basis, exhibited identical mobilities by SDS-gradient polyacrylamide gel electrophoresis and pH 4.3 disc-gel electrophoresis, and gave precipitin lines of antigenic identity on Ouchterlony analysis with goat antibody to the angiotensin II-generating protease.
Cytochalasin B-treated human neutrophils stimulated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine released beta-glucuronidase, lysozyme, and angiotensin II-generating protease in a dose-dependent fashion, consistent with localization of this protease to the neutrophil granule.
When purified neutrophils were disrupted by nitrogen cavitation and fractionated by differential centrifugation, 44 and 24% of the angiotensin II-generating activity was in the lysosomal and undisrupted cell fractions, respectively. A human neutrophil protease, initially termed neutral peptide-generating protease, has been shown to cleave angiotensin II directly from angiotensinogen and has been identified as leukocyte cathepsin G.
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