Abstract

DO.09.05

Müller cell-derived bFGF in retinal ischemia

Yousef Yafai1, Ianors Iandiev1, Johannes Lange1, Wolfram Eichler1, Andreas Reichenbach2, Andreas Bringmann1, Peter Wiedemann1
1Augenklinik, Universität Leipzig, 2Paul-Flechsig Institute, Universität Leipzig

Purpose
To determine the regulation of basic fibroblast growth factor (bFGF) in glial (Müller) cells under conditions of ischemic/ hypoxic retinopathy.
Methods
Transient retinal ischemia was induced in rat eyes by raising the intraocular pressure above the systolic pressure, and bFGF was determined in the retina. Furthermore, bFGF was investigated in surgically excised retinal tissues of patients with ischemic diabetic retinopathy, and using primary guinea-pig Müller cell cultures exposed to hypoxia. bFGF expression and secretion were studied by immunohistochemistry, real-time RT-PCR, and ELISA.
Results
Retinal Müller cells demonstrated an increased level of bFGF immunoreactivity in fibrovascular tissues from patients with diabetes compared with retinal tissues from subjects with non-hypoxic pathologic myopia. In the ischemic rat retina, Müller cells contributed significantly to bFGF release when compared to non-ischemic retina. In Müller cell cultures severe hypoxia (0% O2) induced an increase of bFGF mRNA and protein levels. However, there was no effect on bFGF production in mild hypoxia (5% O2).
Conclusions
These results suggest that Müller cells produce and secrete bFGF under certain conditions including severe hypoxia. The angiogenic activity of Müller cell-derived bFGF may contribute to the neovascular process in the retinal tissue in diabetic proliferative retinopathy.

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