Purchase this article with an account.
A.H. Wolf; Angiopoietin Expression in central and peripheral Retinal Pigment Epithelium . Invest. Ophthalmol. Vis. Sci. 2004;45(13):1897.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Angiopoietins are angiogenic factors that regulate angiogenesis by binding to the TIE receptors. Tight interaction with VEGF and the Angiotensin system has been shown before. While Angiopoetin1 induces changes that play a role in later stages of angiogenesis, Angiopoietin2 is more important in the initial process of angiogenesis. In contrast to Angiopoietin1, Angiopoietin2 does not induce phosphorylation of the TIE2 receptor and thus acts as an natural antagonist to Angiopoietin1. Aim of our study was to investigate differences in the expression profile of the Angiopoietin/TIE2 system in central and retinal pigment epithelium (RPE) and thus further elucidate the role of the angiopoietins in chorioidal neovascularisation and macular edema. Methods: RPE from a zone of 36mm² was preparated from the posterior pole as well as from an area close to the ora serrata of human globes using a specially designed device. For further investigation, protein and RNA was extracted. Investigation of the expression profile was performed by Northern–Blot analysis, Western–Blot analysis and semiquantitave PCR. In Addition, other angiogenic factors such as Endostatin, Angiostatin, PEDF and VEGF were analysed. Results: We could show that there is a difference of Angiopoietin2–expression in central and peripheral RPE with the peripheral RPE expressing more Angiopoietin2 than central RPE. Expression also seemed to differ inter–individually. We could not detect any striking difference in the expression of Angiopoietin1 and TIE2 receptor. Other investigated angiogenic factors showed no striking difference in central/peripheral expression profile. Conclusion: Since Angiopoietin2 is considered to play an important role in the initial process of angiogenesis, weak expression of Angiopoietin2 in central RPE may serve as an autoprotection against neovascularisation of the macula. On the other hand, the absence of the natural antagonist to Angiopoietin1 may allow Angiopoietin1 to function as a major player and provoke macula edema in diseases such as diabetic maculopathy.
This PDF is available to Subscribers Only