title: Apelin in epiretinal membranes of patients with proliferative diabetic retinopathy.
abstract: OBJECTIVE
  Formation of epiretinal membranes (ERMs) in the posterior fundus results in visual impairment. ERMs have been associated with numerous clinical conditions, including proliferative diabetic retinopathy (PDR), a neovascular disease. Apelin has been identified as a novel angiogenesis contributor. The aim of this study was to investigate the correlation between apelin and ERMs after PDR.
  
  
  METHODS
  ERM samples were obtained by vitrectomy from 12 subjects with PDR (aged 57±6 years; duration of diabetes 16±7 years), and 12 subjects with idiopathic ERM (aged 68±5 years). The samples were processed for immunohistochemistry and reverse transcription-PCR (RT-PCR). We also analyzed samples from patients with PDR who received an intravitreal injection of bevacizumab (IVB) before vitrectomy.
  
  
  RESULTS
  The mRNA expression of apelin was significantly higher in the PDR ERMs than in the idiopathic ERMs. Accordingly, immunohistochemical analysis revealed strong expression of apelin in all eight PDR ERMs without IVB, and was double-labeled with glial fibrillary acidic protein antibody (GFAP), platelet endothelial cell adhesion molecule-1 (CD31), cytokeratin (CK) and vascular endothelial growth factor (VEGF) but not with fibronectin. They were mainly located in the adventitia. In contrast, the expression of apelin was lower in the PDR ERMs after IVB and the idiopathic ERMs.
  
  
  CONCLUSIONS
  The results showed that apelin was involved in the formation of ERMs and promoted the formation of adventitia, including glial, endothelial, and RPE cells. Bevacizumab blocked the expression of apelin and regressed gliosis and angiogenesis.
authors.affiliation: Department of Ophthalmology, People's Hospital, Peking University, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China ; Department of Ophthalmology, Inner Mongolia People's Hospital, Huhhot, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Department of Ophthalmology, People's Hospital, Peking University, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China ; Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Ophthalmology, People's Hospital, Peking University, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China ; Department of Ophthalmology, The Third Hospital, Peking University, Beijing, China.
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Xu
authors.affiliation: Department of Ophthalmology, People's Hospital, Peking University, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Yan-Rong
authors.initials: YR
authors.lastname: Jiang
mesh_terms: D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000073861:Apelin; D000068258:Bevacizumab / Q000008:administration & dosage; D003930:Diabetic Retinopathy / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D019773:Epiretinal Membrane / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D058449:Intravitreal Injections; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015861:Retinal Neovascularization
chemical_list: C115436:APLN protein, human; D020533:Angiogenesis Inhibitors; D000073861:Apelin; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D000068258:Bevacizumab