title: Lack of lymphatics and lymph node-mediated immunity in choroidal neovascularization.
abstract: OBJECTIVE
  Inflammation and immune cells regulate choroidal neovascularization (CNV) and could become therapeutic targets in age-related macular degeneration (AMD). Lymphangiogenesis is a key component of various inflammatory diseases. Whether lymphangiogenesis and lymph node-mediated immunity are involved in the pathogenesis of AMD is not understood.
  
  
  METHODS
  To investigate lymphangiogenesis in CNV, we generated CNV in animals by laser and studied surgically removed CNV membranes from uveitis and AMD patients. Immunohistochemistry was performed with lymphatic vessel endothelial hyaluronate receptor 1 (LYVE-1) and podoplanin antibodies. VEGF-C and VEGFR-3 expressions were examined with immunohistochemistry and Western blotting. To examine the role of lymph node in CNV, we lasered lymphotoxin alpha-deficient mice (LTα-/-) and measured the CNV volume.
  
  
  RESULTS
  Immunohistochemistry showed that LYVE-1(+) macrophages infiltrated in acutely induced CNV, although lymphatic tubes did not form. CNV membranes from patients did not show LYVE-1(+)podoplanin(+) vessels, suggesting the lack of lymphangiogenesis in AMD and uveitis. Western blots and immunostaining revealed VEGF-C and VEGFR-3 expression in CNV lesions, mainly in macrophages and angiogenic endothelial cells. Using fluorescent microsphere tracers, we show a path for cellular migration from the eye to the cervical lymph nodes (LNs) during CNV. However, CNV injury did not cause LN swelling. CNV volume did not differ between wild-type and LN-deficient mice, suggesting that LN is not a key component of early CNV formation.
  
  
  CONCLUSIONS
  Laser-induced CNV is not primarily dependent on acquired immunity, nor does the fundus injury affect peripheral LNs. Our results reveal a previously unknown cellular connection between the ocular fundus and the cervical LNs. This connection that in function resembles lymphatics is actively utilized in CNV.
authors.affiliation: Center for Excellence in Functional and Molecular Imaging, Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Nakao
authors.forename: Souska
authors.initials: S
authors.lastname: Zandi
authors.forename: Ri-ichiro
authors.initials: R
authors.lastname: Kohno
authors.forename: Dawei
authors.initials: D
authors.lastname: Sun
authors.forename: Takahito
authors.initials: T
authors.lastname: Nakama
authors.forename: Keijiro
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yoshida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Enaida
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Ali
authors.initials: A
authors.lastname: Hafezi-Moghadam
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D020256:Choroidal Neovascularization / Q000209:etiology / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007834:Lasers; D042583:Lymphangiogenesis; D042601:Lymphatic Vessels / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D008562:Membrane Glycoproteins / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D042582:Vascular Endothelial Growth Factor C / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000276:immunology; D000098853:Podoplanin
chemical_list: D015415:Biomarkers; D008562:Membrane Glycoproteins; D042582:Vascular Endothelial Growth Factor C; D040321:Vascular Endothelial Growth Factor Receptor-3; D033921:Vesicular Transport Proteins; C119248:LYVE1 protein, human; C117468:PDPN protein, human; D000098853:Podoplanin
keywords: AMD; LYVE-1; VEGF-C; VEGFR-3; macrophage; uveitis