Expression profiles of cytokines and chemokines in vitreous fluid in diabetic retinopathy and central retinal vein occlusion

The involvement of cytokines and chemokines in vitreous fluid is important in the development and progression of diabetic retinopathy (DR) and central retinal vein occlusion (CRVO). In this study, the concentrations of cytokines and chemokines in the vitreous fluid of eyes with DR and CRVO were measured and compared. We studied 76 eyes with proliferative DR and diabetic macular edema (DR group), 10 eyes with CRVO (CRVO group), and 23 eyes with an epiretinal membrane and macular hole (control group), among a series of 160 eyes from which vitreous fluid samples were collected during vitrectomy. The vitreous fluid samples were collected by suction with a vitreous cutter at the initial stage of vitrectomy. Twenty-seven different cytokines and chemokines were measured simultaneously using an array system (Bio-Plex(A (R))) with beads combined with antibodies (Bio-Rad), as follows: interleukin (IL)-1 beta, IL-1 receptor agonist, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-17, eotaxin, basic fibroblast growth factor, granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-gamma, interferon-inducible 10-kDa protein (IP-10), monocytochemotactic protein-1 (MCP-1), macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta, platelet-derived growth factor (PDGF)-BB, regulated upon activation, normal T cell expressed and secreted, tumor necrosis factor alpha (TNF-alpha), and vascular endothelial growth factor (VEGF). Compared to the control group, the levels of IL-6, IL-8, IL-10, IL-13, IP-10, MCP-1, MIP-1 beta, PDGF and VEGF in the vitreous fluid were significantly higher in the DR group, while the levels of IL-1 beta, IL-2, IL-5, IL-8, IL-9, IL-10, IL-12, IL-13, eotaxin, G-CSF, IFN-gamma, IP-10, MCP-1, MIP-1 beta, TNF-alpha and VEGF were significantly higher in the CRVO group. Compared to the DR group, IL-2, IL-9, IL-12, MCP-1 and IFN-gamma were significantly elevated in the CRVO group. Multivariate regression analysis revealed that among 6 factors correlated to VEGF in the DR group, IL-10 and IL-13 were more positively correlated and PDGF was most inversely correlated to VEGF. In addition to inflammatory cytokines and neurotrophic factors such as VEGF, anti-inflammatory cytokines such as IL-10 and IL-13 may be involved more in the pathogenesis of DR and CRVO than in other diseases; cytokines and chemokines may also be correlated to VEGF in the vitreous fluid. It is also suggested that the inflammatory reaction may be more activate in CRVO than in DR.