title: NGF/anti-VEGF combined exposure protects RCS retinal cells and photoreceptors that underwent a local worsening of inflammation.
abstract: OBJECTIVE
  Our previous study highlighted the potential nerve growth factor (NGF) effect on damaged photoreceptors from a rat model of spontaneous Retinitis Pigmentosa (RP). Herein, we tested the combined NGF/anti-vascular endothelial growth factor (αVEGF) effect on cultured retinal cells isolated from Royal College of Surgeons (RCS) rats receiving an intravitreal VEGF injection (iv-VEGF) to exacerbate retinal inflammation/neovascularization.
  
  
  METHODS
  RCS (n = 75) rats were equally grouped as untreated (n = 25), iv-saline (single saline intravitreal injection; n = 25) and iv-VEGF (single VEGF intravitreal injection; n = 25). Morphological and biochemical analysis or in vitro stimulations with the biomolecular investigation were carried out on explanted retinas. Isolated retinal cells were treated with NGF and αVEGF, either alone or in combination, for 6 days and cells were harvested for morphological and biomolecular analyses.
  
  
  RESULTS
  Infiltrating inflammatory cells were detected in iv-VEGF exposed RCS retinas, indicative of exacerbated inflammation and neovascularization. In cell cultures, NGF/αVEGF significantly increased retinal cell survival as well as rhodopsin expression and neurite outgrowth in photoreceptors. Particularly, NGF/αVEGF upregulated Bcl-2 mRNA, downregulated Bax mRNA, upregulated trkANGFRmRNA and finally upregulated both NGF mRNA and protein.
  
  
  CONCLUSIONS
  These data confirm and extend our previous findings on NGF-photoreceptor crosstalk, highlighting that the NGF/αVEGF combination might be an interesting approach for improving neuroprotection of RCS retinal cells and likewise photoreceptors in the presence of neovascularization. Further studies are required to translate this in vitro approach into clinical practice.
authors.affiliation: Institute of Cell Biology and Neurobiology, CNR, Rome, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Rocco
authors.affiliation: Research Laboratories in Ophthalmology, IRCCS-G.B. Bietti Foundation, Via Santo Stefano Rotondo, 6 I-00184, Rome, Italy.
authors.forename: Bijorn Omar
authors.initials: BO
authors.lastname: Balzamino
authors.affiliation: Research Laboratories in Ophthalmology, IRCCS-G.B. Bietti Foundation, Via Santo Stefano Rotondo, 6 I-00184, Rome, Italy.
authors.forename: Graziana
authors.initials: G
authors.lastname: Esposito
authors.affiliation: Institute of Cell Biology and Neurobiology, CNR, Rome, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Petrella
authors.affiliation: Institute of Cell Biology and Neurobiology, CNR, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Aloe
authors.affiliation: Research Laboratories in Ophthalmology, IRCCS-G.B. Bietti Foundation, Via Santo Stefano Rotondo, 6 I-00184, Rome, Italy. amicera@gmail.com.
authors.forename: Alessandra
authors.identifier: http://orcid.org/0000-0002-9375-6071
authors.initials: A
authors.lastname: Micera
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D000068258:Bevacizumab / Q000008:administration & dosage*; D002470:Cell Survival; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D058449:Intravitreal Injections; D008297:Male; D018613:Microscopy, Confocal; D020932:Nerve Growth Factor / Q000494:pharmacology*; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects / Q000473:pathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D012313:RNA / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D012174:Retinitis Pigmentosa / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors*
chemical_list: D020533:Angiogenesis Inhibitors; C000617196:Bcl2 protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab; D012313:RNA; D020932:Nerve Growth Factor
keywords: Anti-VEGF; Apoptosis; NGF; Neuroprotection; Retinal degeneration; Retinitis pigmentosa