title: Immunoreactive endothelin-1 in the vitreous humor and epiretinal membranes of patients with proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To investigate the potential role of endothelin-1 (ET-1), a potent vasoconstrictor with mitogenic properties, in the pathogenesis of proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Plasma and vitreous samples were collected from normal patients (controls; n = 25), diabetic patients with PDR (n = 25), and diabetic patients with non-PDR (n = 25). The patients had to have epiretinal membranes (ERMs) or other ocular conditions that made them candidates for vitrectomy. Immunoreactive ET-1 (IR-ET-1) was assayed in plasma and vitreous samples by radioimmunoassay. IR-ET-1 was immunohistochemically localized in ERMs. Expression of endothelin receptors A (ETA) and B (ETB) was confirmed by reverse transcription-polymerase chain reaction analysis.
  
  
  RESULTS
  IR-ET-1 levels in plasma and vitreous samples from diabetic patients were higher (P < 0.0001) than those in samples from the control group. The levels for patients with PDR were even higher (P < 0.0001) than those for patients with non-PDR. Eyes with ERMs in the PDR group had the highest vitreous IR-ET-1 levels (14.67 +/- 0.67 pg/mL). IR-ET-1 was localized in the cellular and stromal components of ERMs in diabetic and nondiabetic patients. Furthermore, the ETA and ETB receptors were expressed in both diabetic and nondiabetic ERMs.
  
  
  CONCLUSIONS
  Diabetic patients with PDR and ERMs had the highest plasma and vitreous IR-ET-1 levels. ET-1 and its ETA and ETB receptors were present in ERMs. These data suggest that ET-1 is involved in diabetic vitreoretinal disease.
authors.affiliation: Departamento de Oftalmología, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain. MRPUCMHS@telefonica.net
authors.forename: Manuela
authors.initials: M
authors.lastname: Roldán-Pallarés
authors.forename: Raquel
authors.initials: R
authors.lastname: Rollín
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Martínez-Montero
authors.forename: Arturo
authors.initials: A
authors.lastname: Fernández-Cruz
authors.forename: Carmen
authors.initials: C
authors.lastname: Bravo-Llata
authors.forename: Raquel
authors.initials: R
authors.lastname: Fernández-Durango
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism*; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D019773:Epiretinal Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D012333:RNA, Messenger