title: Nerves and neovessels inhibit each other in the cornea.
abstract: OBJECTIVE
  To evaluate the regulatory cross-talk of the vascular and neural networks in the cornea.
  
  
  METHODS
  b-FGF micropellets (80 ng) were implanted in the temporal side of the cornea of healthy C57Bl/6 mice. On day 7, blood vessels (hemangiogenesis) and nerves were observed by immunofluorescence staining of corneal flat mounts. The next group of mice underwent either trigeminal stereotactic electrolysis (TSE), or sham operation, to ablate the ophthalmic branch of the trigeminal nerve. Blood vessel growth was detected by immunohistochemistry for PECAM-1 (CD31) following surgery. In another set of mice following TSE or sham operation, corneas were harvested for ELISA (VEGFR3 and pigment epithelium-derived factor [PEDF]) and for quantitative RT-PCR (VEGFR3, PEDF, and CD45). PEDF, VEGFR3, beta-3 tubulin, CD45, CD11b, and F4/80 expression in the cornea were evaluated using immunostaining.
  
  
  RESULTS
  No nerves were detected in the areas subject to corneal neovascularization, whereas they persisted in the areas that were neovessel-free. Conversely, 7 days after denervation, significant angiogenesis was detected in the cornea, and this was associated with a significant decrease in VEGFR3 (57.5% reduction, P = 0.001) and PEDF protein expression (64% reduction, P < 0.001). Immunostaining also showed reduced expression of VEGFR3 in the corneal epithelial layer. Finally, an inflammatory cell infiltrate, including macrophages, was observed.
  
  
  CONCLUSIONS
  Our data suggest that sensory nerves and neovessels inhibit each other in the cornea. When vessel growth is stimulated, nerves disappear and, conversely, denervation induces angiogenesis. This phenomenon, here described in the eye, may have far-reaching implications in understanding angiogenesis.
authors: Schepens Eye Research Institute, Department of Ophthalmology, Medical School, Boston, Massachusetts, USA. giulio.ferrari@schepens.harvard.edu
authors: Giulio
authors: G
authors: Ferrari
authors: Amir R
authors: AR
authors: Hajrasouliha
authors: Zahra
authors: Z
authors: Sadrai
authors: Hiroki
authors: H
authors: Ueno
authors: Sunil K
authors: SK
authors: Chauhan
authors: Reza
authors: R
authors: Dana
mesh_terms: D000818:Animals; D003315:Cornea / Q000098:blood supply* / Q000294:innervation*; D016510:Corneal Neovascularization / Q000378:metabolism / Q000503:physiopathology*; D003714:Denervation; D004195:Disease Models, Animal; D004572:Electrolysis; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D017493:Leukocyte Common Antigens / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009410:Nerve Degeneration / Q000378:metabolism / Q000503:physiopathology*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D009880:Ophthalmic Artery / Q000378:metabolism / Q000503:physiopathology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015843:Serpins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014276:Trigeminal Nerve / Q000378:metabolism / Q000503:physiopathology*; D014404:Tubulin / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D005136:Eye Proteins; D017493:Leukocyte Common Antigens; D009414:Nerve Growth Factors; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012333:RNA, Messenger; D015843:Serpins; D014404:Tubulin; D040321:Vascular Endothelial Growth Factor Receptor-3; D000099174:Pigment Epithelium-Derived Factor; C462941:beta3 tubulin, mouse; C516770:Ptprc protein, mouse