Abstract

P 267

Ultrastructural changes in the PDR membranes after the application of Bevacizumab (Avstin)

Christina Vidinova1, Pravoslava Guguchkova2
1Department of Ophthalmology, Military Medical Academy Sofia, Sofia, Bulgaria; 2Department of Ophthalmology, Vitreo-retinal, Eye Hospital "Zrenie", Sofia, Bulgaria

Objective:  
Proliferative diabetic retinopathy (PDR) is a sight threatening diseases. The aim of our study is to examine the ultrastructural changes in the PDR membranes after the application of intravitreal Bevacizumab (Avastin).
Methods:
In our study 24 PDR patients and 9 PDR patients with vitreous haemorrhage were enrolled.  They all underwent complete ophthalmologic examination including OCT. In all heamophthalm patients intravitreal Avastin (1.25) has been applied. Later in all cases pars plana vitrectomy was performed. Proliferations taken directly from the eye have been studied transmission, scanning electron microscopically and with Safranin O.
Results: 
The fibrovascular proliferations in PDR consisted mostly of fibroblasts and occasional macrophages. The prevailing type of blood vessels had only one thin layer of endothelial cells, very thin Basal membrane and no perycites. Safranin O staining showed dense proteoglycan –collagen network. In the Avstin treated group occluded new-vessels and reduction of the endothelial fenestration were observed. Apart from numerous fibroblasts, significant in number macrophages, leucocytes and elements of the blood were present. The number of proteoglycans in the matrix was increased.
Conclusion:
Our results point out that Avastin’s application influences PDR membrane ultrastructure. It provokes reduction of the neovascularization and oedema through vessel occlusion and changes in the endothelial cells. It also accelerates removal of intravitreal blood. Bevacizumab however can be responsible for complications of fibrosis and traction retinal detachments. That is why patients converged to the treatment should be carefully selected and constantly monitored.

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