title: Anti-vascular endothelial growth factor acts on retinal microglia/macrophage activation in a rat model of ocular inflammation.
abstract: OBJECTIVE
  To evaluate whether anti-vascular endothelial growth factor (VEGF) neutralizing antibodies injected in the vitreous of rat eyes influence retinal microglia and macrophage activation. To dissociate the effect of anti-VEGF on microglia and macrophages subsequent to its antiangiogenic effect, we chose a model of acute intraocular inflammation.
  
  
  METHODS
  Lewis rats were challenged with systemic lipopolysaccharide (LPS) injection and concomitantly received 5 µl of rat anti-VEGF-neutralizing antibody (1.5 mg/ml) in the vitreous. Rat immunoglobulin G (IgG) isotype was used as the control. The effect of anti-VEGF was evaluated at 24 and 48 h clinically (uveitis scores), biologically (cytokine multiplex analysis in ocular media), and histologically (inflammatory cell counts on eye sections). Microglia and macrophages were immunodetected with ionized calcium-binding adaptor molecule 1 (IBA1) staining and counted based on their differential shapes (round amoeboid or ramified dendritiform) on sections and flatmounted retinas using confocal imaging and automatic quantification. Activation of microglia was also evaluated with inducible nitric oxide synthase (iNOS) and IBA1 coimmunostaining. Coimmunolocalization of VEGF receptor 1 and 2 (VEGF-R1 and R2) with IBA1 was performed on eye sections with or without anti-VEGF treatment.
  
  
  RESULTS
  Neutralizing rat anti-VEGF antibodies significantly decreased ocular VEGF levels but did not decrease the endotoxin-induced uveitis (EIU) clinical score or the number of infiltrating cells and cytokines in ocular media (interleukin [IL]-1β, IL-6, tumor necrosis factor [TNF]-α, and monocyte chemoattractant protein [MCP]-1). Eyes treated with anti-VEGF showed a significantly decreased number of activated microglia and macrophages in the retina and the choroid and decreased iNOS-positive microglia. IBA1-positive cells expressed VEGF-R1 and R2 in the inflamed retina.
  
  
  CONCLUSIONS
  Microglia and macrophages expressed VEGF receptors, and intravitreous anti-VEGF influenced the microglia and macrophage activation state. Taking into account that anti-VEGF drugs are repeatedly injected in the vitreous of patients with retinal diseases, part of their effects could result from unsuspected modulation of the microglia activation state. This should be further studied in other ocular pathogenic conditions and human pathology.
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France.
authors: Aude
authors: A
authors: Couturier
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France ; Assistance Publique Hôpitaux de Paris, Hôtel-Dieu de Paris, department of Ophthalmology, Hôpital Hôtel-Dieu, Paris, France.
authors: Elodie
authors: E
authors: Bousquet
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France.
authors: Min
authors: M
authors: Zhao
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France.
authors: Marie-Christine
authors: MC
authors: Naud
authors: Inserm, U1138, CICC, Université René Descartes Sorbonne Paris Cité, Université Pierre et Marie Curie Paris Centre de Recherche des Cordeliers, Paris, France.
authors: Christophe
authors: C
authors: Klein
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France.
authors: Laurent
authors: L
authors: Jonet
authors: Assistance Publique Hôpitaux de Paris, Hôtel-Dieu de Paris, department of Ophthalmology, Hôpital Lariboisière, Paris, France.
authors: Ramin
authors: R
authors: Tadayoni
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France.
authors: Yvonne
authors: Y
authors: de Kozak
authors: Inserm, U1138, Team 17, Physiopathology of ocular diseases : Threrapeutic innovations, Université René Descartes Sorbonne Paris Cité, Centre de Recherche des Cordeliers, Paris, France ; Department of Ophtahlmology of Lausanne University, Jules Gonin Ophthalmic hospital, Lausanne, Switzerland.
authors: F
authors: F
authors: Behar-Cohen
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D057134:Antibodies, Neutralizing / Q000494:pharmacology / Q000627:therapeutic use*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002452:Cell Count; D004195:Disease Models, Animal; D006801:Humans; D008070:Lipopolysaccharides; D008262:Macrophage Activation / Q000187:drug effects*; D008840:Microfilament Proteins / Q000378:metabolism; D017628:Microglia / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D009500:Neutralization Tests; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D051381:Rats; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D014605:Uveitis / Q000188:drug therapy* / Q000473:pathology*; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: C100745:Aif1 protein, rat; D000893:Anti-Inflammatory Agents; D057134:Antibodies, Neutralizing; D002135:Calcium-Binding Proteins; D008070:Lipopolysaccharides; D008840:Microfilament Proteins; D042461:Vascular Endothelial Growth Factor A; D052247:Nitric Oxide Synthase Type II; D040262:Receptors, Vascular Endothelial Growth Factor