title: Panretinal photocoagulation induces pro-inflammatory cytokines and macular thickening in high-risk proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To investigate whether pan-retinal photocoagulation (PRP) affects vitreous levels of cytokines and macular thickening in patients with high-risk proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Fourteen patients with bilateral high-risk PDR--which requires pars plana vitrectomy (PPV)--but without a history of retinal photocoagulation participated in this study. Before PPV, one eye received PRP, and the other eye did not. The concentrations of cytokines of vascular endothelial growth factor (VEGF), stromal derived factor-1 (SDF-1), interleukin-6 (IL-6) and regulated upon activation, normal T-cell expressed and secreted (RANTES) were measured in each vitreous sample obtained at PPV. Macular thickness obtained by optical coherence tomography was also monitored during clinical course.
  
  
  RESULTS
  After the PRP, macular thickness in PRP-pretreated eye showed temporal increase. Vitreous levels of IL-6 and RANTES in PRP pre-treated eye were significantly higher than levels in control eyes (p = 0.013, p = 0.033). Although macular thickness in control was correlated to vitreous levels of VEGF and IL-6 (p = 0.022, p = 0.003), that in PRP-pretreated eye was closely correlated to IL-6 and RANTES (p = 0.002, p = 0.011). After the PPV, macular thickness in both eye groups improved, and there was no significant difference between both eye groups 3 months after the PPV.
  
  
  CONCLUSIONS
  In patients with high-risk PDR, PRP cause temporal worsening of macular edema linked with pro-inflammatory cytokines of IL-6 and RANTES, but not with VEGF and SDF-1. Thus, PRP-induced macular edema was caused by inflammation, while visual prognosis after PPV was not influenced by pretreatment of PRP.
authors.affiliation: Department of Ophthalmology, NTT East Japan Tohoku Hospital, 2-29-1 Yamato, Wakabayashi, Sendai, Miyagi 984-8560, Japan. masahiko@v101.vaio.ne.jp
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shimura
authors.forename: Kanako
authors.initials: K
authors.lastname: Yasuda
authors.forename: Toru
authors.initials: T
authors.lastname: Nakazawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Abe
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiono
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Iida
authors.forename: Taiji
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Kohji
authors.initials: K
authors.lastname: Nishida
mesh_terms: D000368:Aged; D018946:Chemokine CCL5 / Q000378:metabolism; D054377:Chemokine CXCL12 / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000378:metabolism / Q000601:surgery*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D017075:Laser Coagulation / Q000009:adverse effects*; D008269:Macular Edema / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000473:pathology* / Q000601:surgery; D041623:Tomography, Optical Coherence; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: C483024:CCL5 protein, human; D018946:Chemokine CCL5; D054377:Chemokine CXCL12; D016207:Cytokines; C508600:IL6 protein, human; D015850:Interleukin-6; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A