Abstract
Purpose: :
To determine the vitreous concentration of complement fragment C5a in patients with proliferative diabetic retinopathy (PDR) and to elucidate the relation between C5a and various inflammatory cytokines.
Methods: :
Vitreous and aqueous humor samples were obtained at the time of vitrectomy from 20 eyes of 19 PDR patients and from 14 eyes of 14 patients with macular disease who has no history of diabetes as controls. Vitreous and aqueous concentrations of human C5a, vascular endothelial growth factor (VEGF), interferon-inducible protein-10 (IP-10), interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1) and monokine induced by interferon-γ (Mig) were quantified using FACS Caliber® flow cytometer.
Results: :
Aqueous and vitreous concentration of C5a increased significantly in patients with PDR 303.8, 1,079.3pg/ml respectively compared with controls 53.4, 201.7 pg/ml. (P=0.02, P=0.01). Aqueous concentration of VEGF, IP-10, IL-8, MCP-1, Mig were significantly higher in PDR patients 479.8, 251.9, 174.4, 2141.0, 72.3pg/ml compared with control patients (P=0.01, 0.01, 0.02, 0.01, 0.02). In PDR patients, aqueous concentration of C5a correlated significantly with those of IP-10 (P<0.01) and IL-8 (P<0.01). Vitreous concentration of VEGF, IP-10, IL-8, MCP-1, Mig were significantly higher in PDR patients 1082.7, 237.9, 80.6, 1553.8, 47.5pg/ml compared with control patients (P=0.001, 0.005, 0.01, 0.01, 0.03). In PDR patients, vitreous concentration of C5a revealed positive correlation with those of IP-10 (P<0.01), VEGF (P=0.05) and MCP-1 (P=0.01).
Conclusions: :
Our results suggest that C5a may play a role in the pathogenesis of PDR and work in concert with inflammatory cytokines such as VEGF, MCP-1, IP-10 and IL-8 in pathological angiogenesis.
Keywords: diabetic retinopathy • cytokines/chemokines • vascular endothelial growth factor