title: Chemokines in proliferative diabetic retinopathy and proliferative vitreoretinopathy.
abstract: OBJECTIVE
  To determine levels of the chemokines CCL1/I-309, CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL7/MCP-3, CCL8/MCP-2, CXCL5/ENA-78, CXCL6/GCP-2, CXCL10/IP-10, and CXCL11/I-TAC in the vitreous humor and serum, from patients with proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and rhegmatogenous retinal detachment with no PVR (RD), and to investigate the expression of MCP-1, CXCL12/SDF-1, and the chemokine receptor CXCR3 in epiretinal membranes.
  
  
  METHODS
  Paired vitreous humor and serum samples were obtained from patients undergoing vitrectomy for the treatment of RD (57 specimens), PVR (32 specimens), and PDR (88 specimens). The levels of chemokines were measured by enzyme-linked immunosorbent assays. Eighteen PDR and 5 PVR membranes were studied by immunohistochemical techniques.
  
  
  RESULTS
  Of all the chemokines studied, only MCP-1 and IP-10 were detected in vitreous humor samples. MCP-1 levels in vitreous humor samples were significantly higher than in serum samples (p < 0.001). MCP-1 levels were significantly higher in vitreous humor samples from patients with PVR and PDR compared with RD (p = 0.0002). MCP-1 levels in vitreous humor samples from patients with active PDR were significantly higher than in inactive PDR cases (p = 0.0224). IP-10 levels in vitreous humor samples were significantly higher than in serum samples (p = 0.0035). IP-10 levels were significantly higher in vitreous humor samples from patients with PVR and PDR compared with RD (p = 0.0083). The incidence of IP-10 detection in vitreous humor samples was significantly higher in active PDR cases compared with inactive cases (p = 0.0214). There was a significant association between the incidence of IP-10 detection and increased levels of MCP-1 in vitreous humor samples from all patients, and patients with RD and PDR (p < 0.001 for all comparisons). MCP-1, and SDF-1 were localized in myofibroblasts in PVR and PDR membranes and in vascular endothelial cells in PDR membranes. CXCR3 was expressed by vascular endothelial cells in PDR membranes.
  
  
  CONCLUSIONS
  MCP-1, IP-10 and SDF-1 may participate in pathogenesis of PVR and PDR. Myofibroblasts and vascular endothelial cells are the major cell types expressing MCP-1, SDF-1, and CXCR3 in epiretinal membranes.
authors.affiliation: Department of Ophthalmology, College of Medicine, King Saud University, King Abdulaziz University Hospital, Airport Road, PO Box 245, Riyadh 11411, Saudi Arabia. abuasrar@KSU.edu.sa
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Abu El-Asrar
authors.forename: Sofie
authors.initials: S
authors.lastname: Struyf
authors.forename: Dustan
authors.initials: D
authors.lastname: Kangave
authors.forename: Karel
authors.initials: K
authors.lastname: Geboes
authors.forename: Jo
authors.initials: J
authors.lastname: Van Damme
mesh_terms: D000328:Adult; D018925:Chemokines / Q000097:blood / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000097:blood / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018630:Vitreoretinopathy, Proliferative / Q000097:blood / Q000378:metabolism*; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D018925:Chemokines