title: Is Angiostatin Involved in Physiological Foveal Avascularity?
abstract: The primate central retina is characterized by an avascular fovea and well-defined perifoveal capillary plexus. Neither blood vessels nor their accompanying astrocytes enter the fovea during any stage of retinal development; a balance of angiogenic and angiostatic factors probably maintains foveal avascularity throughout life. The aim of this study was to identify potentially angiorepulsive factors involved in the development of the avascular primate retinal fovea.
  
  
  
  Retinas of newborn, juvenile, and adult Callithrix jacchus and Macaca fascicularis monkeys and control human retinas were studied to determine the localization of angiostatin relative to III β-tubulin, glial fibrillary acidic protein, vascular endothelial growth factor (VEGF), platelet endothelial cell adhesion molecule-1 (PECAM), and the angiostatin receptor αvβ3-integrin in the foveal, macular, and peripheral retina. Expression studies were performed using immunohistochemistry (IHC) on retinal whole-mount and paraffin sections, and Western blotting on frozen material. The complex network of the main retinal cell types was identified by IHC of retinal whole mounts.
  
  
  
  In general, lifetime expression of angiostatin was found in all retinas. Colabeling with different markers revealed retinal ganglion cells as the main source of angiostatin expression in the primate retina, whereas PECAM-immunopositive blood capillaries expressed the angiostatin receptor αvβ3-integrin, and capillary-associated astrocytes expressed VEGF.
  
  
  
  This study provides the first evidence of angiostatin expression in the primate retina; the expression of angiostatin in the avascular foveal region and the peripheral retina suggests that angiostatin may play a role in the regulation of retinal vascularization, providing a possible explanation for the development and persistence of an avascular fovea.
authors: Department of Ophthalmology Clinic for Diseases of the Anterior Segments of the Eyes, Essen University Hospital, Essen, Germany|Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Michael R. R.
authors: MR
authors: Böhm
authors: Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Florian
authors: F
authors: Hodes
authors: Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Katrin
authors: K
authors: Brockhaus
authors: Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Stephanie
authors: S
authors: Hummel
authors: Centre for Reproductive Medicine and Andrology, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Stefan
authors: S
authors: Schlatt
authors: Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Harutyun
authors: H
authors: Melkonyan
authors: Institute of Experimental Ophthalmology, School of Medicine, Westfalian Wilhelms-University of Münster, Münster, Germany
authors: Solon
authors: S
authors: Thanos
mesh_terms: D000368:Aged; D043168:Angiostatins / Q000096:biosynthesis*; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002144:Callithrix; D002196:Capillaries / Q000166:cytology / Q000378:metabolism; D005260:Female; D005584:Fovea Centralis / Q000098:blood supply* / Q000166:cytology / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D008252:Macaca fascicularis; D008297:Male; D008875:Middle Aged; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D043168:Angiostatins