Article
Influence of verteporfin photodynamic therapy on the expression of vascular endothelial growth factor in choroidal neovascular membranes
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Published: | September 22, 2004 |
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Outline
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Objective
To evaluate the impact of verteporfin photodynamic therapy (PDT) on the expression and distribution of vascular endothelial growth factor (VEGF) in choroidal neovascular membranes (CNV) secondary to age related macular degeneration (AMD).
Methods
Retrospective review of an interventional case series of fifteen patients who underwent removal of CNV (n=15) secondary to ARMD after treatment with PDT 3 to 246 days previously. CNV were stained for CD 34, Endoglin (CD 105), Ki-67 and VEGF. Thirty CNV secondary to AMD without previous treatment were used as control. Immunohistological results were correlated with clinical findings and fluorescein angiography.
Results
CNV without PDT disclosed different degrees of VEGF expression by endothelial cells. Retinal pigment epithelium cells (RPE), in contrast, mostly displayed no or weak immunoreactivity. However, CNV treated by PDT were characterized by a strong VEGF expression in RPE cells. Weak endothelial and stromal VEGF expression 3 days after PDT was contrasted by an upregulation at greater post-treatment intervals.
Conclusions
Verteporfin PDT characteristically induces a hypoperfusion of the treated area. The resulting ischemic insult of the tissue is probably responsible for the enhanced VEGF expression by RPE cells and neoangiogenesis.