Abstract
P 092
Components of basement membranes in a modell of laser-induced CNV
Dimitrios A. Karagiannis, Irina Semkova, Norbert Kociok, Liang Yong, Antonia M. Joussen
Labor für experimentelle Ophthalmologie, Universitäts-Augenklinik Düsseldorf
Objective
The main cause of severe vision loss in patients with age-related macular degeneration (AMD) is choroidal neovascularization (CNV).
Basement membranes (BM) are key components of vascular walls, inner limiting membrane, Bruch's membrane, etc.
In vitro has been shown that changes in BM proteins play an important role in angiogenesis. We investigated different BM proteins nidogen-1, nidogen-2, laminins, collagen type-IV and perlecan, their expression and the structure of CNV lesions over a course of time.
Methods
An experimental animal model of AMD was used to investigate the role of BM proteins. Laser photocoagulation was performed to induce rupture of Bruch’s membrane and subsequent neovascular growth in C57Bl/6J (WT) animals. We determined 4 different time points to investigate the changes, 24 hours, 1 week, 2 weeks and 4 weeks after laser procedure.
The choroid was flatmounted and labeled with Isolectin IB-4.
Distribution and expression of the studied proteins in choroid and retina were investigated by immunohistochemistry on paraffin sections.
Results
Flatmount preparation showed the largest lesion sizes 24 hours after laser. 1 week after laser the lesions size decreased. 2 weeks after laser the lesions were confluent.
All proteins were located in Bruch´s membrane and other BMs including vascular walls.
Immunohistochemistry showed the expression of perlecan, laminins, collagenIV in CNV lesions during all timepoints. Nidogen-1 showed its highest expression 2 weeks after laser. Nidogen-1 was not expressed after the 1 week.
Conclusions
The investigated proteins were all expressed in ocular BMs. There was no difference in expression to non-treated animals suggesting that CNV lesions do not change the composing of BMs. The flatmount preparation showed that CNV lesions underwent changes, suggesting a mechanism similar to healing processes in other tissues. Further studies are needed to determine the role of BMs in laser-induced CNV.
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