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A.H. Wolf, D. Kook, A. Yu, A. Kampik, H. Schmid, U.C. Welge–Luessen; Angiopoietin1 is Induced by Oxidative Stress in Retinal Pigment Epithelium (RPE) Cells . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1386.
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Angiopoietin1 (ANG1) and 2 (ANG2) are known as growth factors with the ability to promote and prevent angiogenesis. Recently it was shown that ANG1 and 2 are expressed in choroidal neovascularisation (CNV) membranes. Furthermore it could be demonstrated that ANG1 acts as a survival factor against oxidative stress in endothelium cells. However, on the other hand angiopoietins are known to induce inflammation. In the pathogenesis in of early AMD inflammation as well as oxidative stress in the RPE play an essential role. Therefore the goal of this study was to investigate whether ANG expression is increased in RPE cells after exposure to oxidative stress.
The expression of ANG1 and ANG2 was analysed in native RPE cells by quantitative RT–PCR as well as by Northern blotting. The expression of their receptor TIE2 was investigated by RT–PCR. To evaluate ANG1 and ANG2 expression after oxidative stress cultured RPE cells were exposed to hydrogen peroxide at differing duration (1h–2 hrs, 12 –48 Hrs recuperation) and concentrations (50 – 300 µmol). ANG1 and ANG2 mRNA expression was quantified by RT–PCR.
ANG2 is not expressed in native RPE cells. Oxidative stress increased the expression of ANG1 5fold, whereas ANG2 expression was not influenced. The main receptor of angiopoietins (TIE2) could not be detected in RPE cells.
Oxidative stress increases expression of ANG1 while ANG2 remains unchanged. On one hand increased ANG1 levels could have a protective effect, on the other hand high levels of angiopoietins could trigger inflammation and thus promote ignition or progression of AMD.
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