Angiotensin(1-7) and ACE2, "The Hot Spots" of Renin-Angiotensin System, Detected in the Human Aqueous Humor.
BACKGROUND
The main purpose of the study was to establish whether essential components of the renin-angiotensin system (RAS) exist in the human aqueous humor.


METHODS
Forty-five patients ≥ 60 (74±7) years of age undergoing cataract surgery at Tampere University Hospital were randomly selected for the prospective study. The exclusion criterion was the use of oral antihypertensive medicine acting via renin-angiotensin system. Aqueous humor samples were taken at the beginning of normal cataract extraction. The samples were frozen and stored at -80 °C. The concentrations of intraocular endogenous RAS components Ang(1-7), ACE2, and ACE1 were measured using ELISA.


RESULTS
Concentration medians of Ang(1-7), ACE2, and ACE1 in the aqueous humor were: Ang(1-7) 4.08 ng/ml, ACE2 2.32 ng/ml and ACE1 0.35 ng/ml. The concentrations were significantly higher in glaucomatous than in non-glaucomatous eyes, ACE1 (p=0.014) and Ang(1-7) (p=0.026) vs non-glaucomatous eyes.


CONCLUSIONS
Ang(1-7), ACE2 and ACE1 are found in the human aqueous humor. The observations are consistent with the conception that local tissue-RAS exists in the human eye and it might have a role in the control of intraocular pressure.
BioMediTech, University of Tampere, Tampere, Finland.
Mervi
M
Holappa
BioMediTech, University of Tampere, Tampere, Finland.
Jarkko
J
Valjakka
Department of Ophthalmology, Tampere University Hospital, Tampere, Finland ; SILK, Department of Ophthalmology, School of Medicine, University of Tampere, Tampere, Finland.
Anu
A
Vaajanen
Angiotensin (1-7); angiotensin II; angiotensin converting enzyme 1; angiotensin converting enzyme 2; aqueous humor; glaucoma; renin-angiotensin system