title: Intraocular expression of serum amyloid a and interleukin-6 in proliferative diabetic retinopathy.
abstract: OBJECTIVE
  Because serum amyloid A can regulate angiogenesis, we searched for an association between serum amyloid A and interleukin-6 (IL-6), as proinflammatory factors, and proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Retrospective, comparative study.
  
  
  METHODS
  Seventy-six patients (76 eyes) with PDR and 31 patients (31 eyes) with nondiabetic ocular disease (control group), including idiopathic epiretinal membranes (8 eyes) and idiopathic macular holes (23 eyes), were enrolled. Enzyme-linked immunosorbent assay, dual-color immunofluorescence staining, and semiquantitative reverse-transcription polymerase chain reaction were used to examine the serum amyloid A and IL-6 levels in vitreous and plasma, expression of protein and mRNA of serum amyloid A in the excised membranes, respectively.
  
  
  RESULTS
  Vitreous serum amyloid A and IL-6 levels in the study group were significantly higher than those in the control group (both P < .001), whereas the plasma concentrations of serum amyloid A and IL-6 did not vary significantly between the groups (P = .555 and P = .621, respectively). A significant correlation was observed between the vitreous and plasma levels of serum amyloid A in subjects with PDR (r = 0.525; P < .001). In fibrovascular membranes of the study group, colocalization of endothelial marker CD31 with serum amyloid A and colocalization of fibrillar structure markers fibronectin with serum amyloid A were observed. Expression of serum amyloid A mRNA was significantly higher in fibrovascular membranes with PDR than in idiopathic epiretinal membranes (P = .004).
  
  
  CONCLUSIONS
  Serum amyloid A and IL-6 may be involved with the inflammatory process in the development of PDR. Local expression of serum amyloid A may exist in PDR.
authors.affiliation: Department of Ophthalmology, People's Hospital, Peking University, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Yong
authors.initials: Y
authors.lastname: Tao
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Yan-Rong
authors.initials: YR
authors.lastname: Jiang
mesh_terms: D001824:Body Constitution; D003930:Diabetic Retinopathy / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D019773:Epiretinal Membrane / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D015850:Interleukin-6 / Q000097:blood* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000685:Serum Amyloid A Protein / Q000235:genetics / Q000378:metabolism*; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D012333:RNA, Messenger; D000685:Serum Amyloid A Protein