Abstract
Purpose: :
Integrins are cell surface receptors that relay information from the outside of the cell to the inside based on the surrounding ECM. Several integrin family members have been implicated to play a significant role in mediating the angiogenic response. The integrins implicated include α1 ß1, α2 ß1, α5 ß1, αV ß3, ß3 and αV ß5. The purpose of the study is to investigate the expression and co–localization of integrins and endothelial cells in various stages of Choroidal Neovascularization (CNV).
Methods: :
Twenty–one CNV membranes were collected from eyes via vitreoretinal surgery representing early, mid and late stage CNV development. A double immunohistochemical staining procedure was used to identify the presence and co–localization of integrins and endothelial cells. Primary antibodies against α1 ß1, α2 ß1, α5 ß1, αV ß3, ß3 and αV ß5 were used in combination with primary antibodies against Von Willibrand Factor (VWF) or CD31, both markers of endothelial cells. Secondary antibodies tagged with Alexa–488 or Cy3 and Zeiss Inverted Axiovert 200M Confocal Laser–scanning Microscope (Zeiss–LSM 510 META) were used to visualize immunohistochemical labeling. Tonsil tissues were used as positive control tissue in this study.
Results: :
Cells in CNV membranes expressed α1 ß1, α2 ß1, αV ß3, αV ß5 and ß3, but not α5 ß1 in active CNV lesions. Most of these integrins were co–localized within endothelial cells with αVß3 and αVß5 present in early stage membranes with more mild expression in a subset of membranes at mid to late stage. α1 ß1 and α2 ß1 expression was restricted to early stage of CNV. Integrin α5 ß1 was absent in all tissues.
Conclusions: :
CNV membranes are positive for α1ß1, α2ß1, αVß3, αVß5 and ß3 integrins. Of these, most αV ß3 and ß3 colocalize with endothelial cells within CNV membranes. These results suggest that therapeutic applications focused on blocking αV ß3 and/or ß3 on endothelial cells may be helpful in minimizing neovascularization in choroidal neovascularization.
Keywords: age-related macular degeneration • immunohistochemistry • pathology: human