title: Angiopoietin concentrations in diabetic retinopathy.
abstract: OBJECTIVE
  Angiopoietin 1 and 2 interact with vascular endothelial growth factor (VEGF) to promote angiogenesis in animal and in vitro models. Although VEGF concentrations are elevated, there is little information regarding angiopoietin concentration in the vitreous of patients with diabetic retinopathy.
  
  
  METHODS
  Angiopoietin concentrations were measured by luminescence immunoassay in vitreous samples from 17 patients with non-proliferative diabetic retinopathy (NPDR) and clinically significant diabetic macular oedema (CSMO), 10 patients with proliferative diabetic retinopathy (PDR), and five patients with macular hole (controls) obtained at pars plana vitrectomy.
  
  
  RESULTS
  Angiopoietin 1 concentrations were low in patients with macular hole (median 17 pg/ml) while in NPDR with CSMO they were 2002 pg/ml (range 289-5820 pg/ml) and in PDR 186 pg/ml (range 26-2292 pg/ml). Angiopoietin 2 concentrations in NPDR with CSMO were a median of 4000 pg/ml (range 1341-14 329 pg/ml). For both macular hole and PDR patients angiopoietin 2 was below the limit of detection.
  
  
  CONCLUSIONS
  Angiopoietin 2 concentration was twice that of angiopoietin 1 in NPDR with CSMO. Angiopoietin 2 is the natural antagonist of angiopoietin 1 which is thought to act as an anti-permeability agent. The predominance of angiopoietin 2 may allow VEGF induced retinal vascular permeability in patients with CSMO. The relatively low concentration of both angiopoietin 1 and 2 in patients with proliferative diabetic retinopathy may reflect the established nature of the neovascularisation in cases proceeding to vitrectomy.
authors.affiliation: Moorfields Eye Hospital, Institute of Ophthalmology, London, UK. jigs37@hotmail.com
authors.forename: J I
authors.initials: JI
authors.lastname: Patel
authors.forename: P G
authors.initials: PG
authors.lastname: Hykin
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Gregor
authors.forename: M
authors.initials: M
authors.lastname: Boulton
authors.forename: I A
authors.initials: IA
authors.lastname: Cree
mesh_terms: D000328:Adult; D000368:Aged; D042683:Angiopoietin-1 / Q000032:analysis; D042702:Angiopoietin-2 / Q000032:analysis; D042682:Angiopoietins / Q000032:analysis*; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D005584:Fovea Centralis / Q000473:pathology; D006801:Humans; D008269:Macular Edema / Q000378:metabolism; D008875:Middle Aged; D015861:Retinal Neovascularization / Q000378:metabolism; D012167:Retinal Perforations / Q000378:metabolism / Q000601:surgery; D014821:Vitrectomy; D014822:Vitreous Body / Q000737:chemistry
chemical_list: C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; D042702:Angiopoietin-2; D042682:Angiopoietins