title: Binding of VEGF-A is sufficient to abrogate the disturbing effects of VEGF-B together with VEGF-A on retinal endothelial cells.
abstract: OBJECTIVE
  Inhibition of vascular endothelial growth factor (VEGF) is a promising strategy to treat retinal complications of diabetes. In contrast to VEGF-A binding ranibizumab, aflibercept also binds to other members of the VEGF family including VEGF-B, but potential effects of this factor on permeability and angiogenic processes are unclear. Therefore, we studied how VEGF-B variants as single agents or together with VEGF-A165 might affect proliferation, migration, or barrier function of retinal endothelial cells (REC). Also investigated was the normalization of REC properties with both VEGF-inhibitors to explore if additional targeting of VEGF-B is relevant.
  
  
  METHODS
  Stimulation of proliferation or migration of immortalized bovine REC (iBREC) and disturbance of their barrier by exposure to VEGF-B variants (as single factors or together with VEGF-A165) was determined with or without VEGF-binding proteins being added. Permeability of iBREC was assessed by measuring their transendothelial resistance (TER) and expression of the tight junction protein claudin-1.
  
  
  RESULTS
  VEGF-B167 and VEGF-B186 enhanced proliferation of iBREC but these isoforms did not affect cell migration. Interestingly, ranibizumab completely blocked both migration and proliferation induced by VEGF-A plus VEGF-B. Both VEGF-B variants did also not affect barrier function or claudin-1 expression in a normal or high-glucose environment. Accordingly, binding VEGF-A was enough to normalize a reduced TER and reinstate claudin-1 lost during treatment with this factor in combination with VEGF-B.
  
  
  CONCLUSIONS
  Important properties and functions of REC seem not to be affected by any VEGF-B variant and targeting the key factor VEGF-A is sufficient to normalize growth factor-disturbed cells of this type.
authors: Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075, Ulm, Germany, heidrun.deissler@uniklinik-ulm.de.
authors: Heidrun L
authors: HL
authors: Deissler
authors: Gerhard K
authors: GK
authors: Lang
authors: Gabriele E
authors: GE
authors: Lang
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D015153:Blotting, Western; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D062445:Claudin-1 / Q000378:metabolism; D017097:Electric Impedance; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D000069579:Ranibizumab; D040262:Receptors, Vascular Endothelial Growth Factor / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D012171:Retinal Vessels / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology*; D042561:Vascular Endothelial Growth Factor B / Q000494:pharmacology*
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D062445:Claudin-1; D011993:Recombinant Fusion Proteins; C467484:VEGFA protein, human; C467485:VEGFB protein, human; D042461:Vascular Endothelial Growth Factor A; D042561:Vascular Endothelial Growth Factor B; C533178:aflibercept; D040262:Receptors, Vascular Endothelial Growth Factor; D000069579:Ranibizumab