title: Orbital Angiogenesis and Lymphangiogenesis in Thyroid Eye Disease: An Analysis of Vascular Growth Factors with Clinical Correlation.
abstract: The human orbit is an environment that is vulnerable to inflammation and edema in the setting of autoimmune thyroid disease. Our study investigated the tenet that orbital adipose tissue lacks lymphatic vessels and analyzed the clinicopathologic differences between patients with acute and chronic thyroid eye disease (TED). The underlying molecular mediators of blood and lymphatic vessel formation within the orbital fat also were evaluated.
  
  
  
  Retrospective cohort study.
  
  
  
  The study included fat specimens from 26 orbits of 15 patients with TED undergoing orbital decompression. Orbital fat specimens from patients without TED as well as cadaveric orbital fat served as controls.
  
  
  
  Tissue specimens were processed as formalin-fixed, paraffin-embedded sections or frozen cryosections for immunohistochemistry. Total RNA was extracted and analyzed via quantitative (real-time) reverse-transcription polymerase chain reaction. Clinicopathologic correlation was made by determining the clinical activity score (CAS) of each patient with TED.
  
  
  
  Samples were examined for vascular and lymphatic markers including podoplanin, lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), and cluster of differentiation 31 (CD31) by immunohistochemistry, as well as for mRNA levels of vascular endothelial growth factor (VEGF), VEGF receptors, semaphorin 3F, neuropilin 1, neuropilin 2, podoplanin, and LYVE-1 by quantitative (real-time) reverse-transcription polymerase chain reaction.
  
  
  
  Clinicopathologic correlation revealed increased staining of CD31-positive blood vessels in patients with acute TED with a CAS more than 4, as well as rare staining of podoplanin-positive lymphatic vessels within acutely inflamed orbital fat tissue. Additionally, quantitative (real-time) reverse-transcription polymerase chain reaction analysis demonstrated increased expression of VEGF receptor (VEGFR) 2 as well as VEGF signaling molecules VEGF-A, VEGF-C, and VEGF-D.
  
  
  
  In acute TED, compared with chronic TED and control orbital fat, there is increased blood vessel density, suggesting neovascularization and rare lymphatic vessels suggestive of limited lymphangiogenesis. This proangiogenic and prolymphangiogenic microenvironment is likely the result of the increased expression of VEGFR-2, VEGF-A, VEGF-C, and VEGF-D. These findings imply that orbital edema in acute TED may be mediated, in part, by both the formation of new, immature blood vessels and the formation of lymphatic capillaries that are functionally incapable of draining interstitial fluid.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
authors.forename: Lindsay L
authors.initials: LL
authors.lastname: Wong
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts; Ophthalmic Plastic Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
authors.forename: Nahyoung Grace
authors.initials: NG
authors.lastname: Lee
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
authors.forename: Dhanesh
authors.initials: D
authors.lastname: Amarnani
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts; Ophthalmic Plastic Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Choi
authors.affiliation: Department of Surgery, Harvard Medical School, Children's Hospital of Boston, Boston, Massachusetts.
authors.forename: Diane R
authors.initials: DR
authors.lastname: Bielenberg
authors.affiliation: Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts; Ophthalmic Plastic Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
authors.forename: Suzanne K
authors.initials: SK
authors.lastname: Freitag
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: D'Amore
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts. Electronic address: Leo_Kim@meei.harvard.edu.
authors.forename: Leo A
authors.initials: LA
authors.lastname: Kim
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D000368:Aged; D015415:Biomarkers; D016022:Case-Control Studies; D005260:Female; D049970:Graves Ophthalmopathy / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D042583:Lymphangiogenesis / Q000502:physiology*; D042601:Lymphatic Vessels / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D012189:Retrospective Studies; D042442:Vascular Endothelial Growth Factors / Q000378:metabolism
chemical_list: D015415:Biomarkers; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D042442:Vascular Endothelial Growth Factors; D040262:Receptors, Vascular Endothelial Growth Factor