Aims: The aim of the study was to evaluate the histopathology of neovascular tufts and vitreous samples collected from patients with diabetes.
Methods: Vitreous samples and neovascular tufts were collected from patients with type 1 (n = 13) and (n = 17) type 2 diabetes with proliferative retinopathy, and from controls with a macular hole (n = 5). Neovessels were analysed using immunohistochemistry and vitreous samples with an enzyme-linked immunosorbent assay (ELISA). The main outcome measure was to examine differences in the levels of growth factors in patients with type 1 and type 2 diabetes with proliferative retinopathy.
Results: Vascular endothelial growth factor (VEGF)-A was most strongly present in the samples from patients with type 1 diabetes. In type 2 diabetes, VEGF-D was more abundantly present than in type 1 diabetes. Angiopoietin (ANG)-2 was also abundantly present. Macrophages and nuclear factor kappa B (NFκB) were found, indicating the presence of an inflammatory process in the neovascular tissues.
Conclusions: VEGF-A and ANG-2 are equally important in the neovascular process in both type 1 and type 2 diabetes. VEGF-D is abundantly present in type 2 diabetes. In order to achieve better control of diabetic retinopathy, it might be beneficial to develop treatments that prevent the actions of ANG-2 and VEGF-D.
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Funding This study was supported by grants from Finnish Academy, Finnish Diabetes Research Foundation, Finnish Cultural Foundation, Kuopio University Hospital (EVO Grant 5187), Evald and Hilda Nissi Foundation and Finnish Eye Foundation.
Competing interests None declared. The authors have no financial or proprietary interest in products mentioned in the article.
Ethics approval The study protocol was approved by the Ethical Committee of Kuopio University Hospital and the study conformed with the principles outlined in the Declaration of Helsinki.
Patient consent Obtained