Yoshida S, et al. - The intent here was to determine if the vitreal concentrations of MCP-1, IL-6, IL-8, and VEGF were elevated after unsuccessful vitrectomy in patients with proliferative diabetic retinopathy (PDR). Furthermore, this study ascertained whether the altered levels of these cytokines correlated with the cause for the reoperation. The data revealed that elevated levels of MCP-1, IL-6, and IL-8 could be the cause of the postoperative fibrous proliferation. On the other hand, VEGF could serve as the cause of the neovascularization after unsuccessful vitrectomy in the eyes of PDR patients.

Methods

• Vitreous samples were obtained from 263 eyes of 233 patients: PDR (n=129 eyes), proliferative vitreoretinopathy (PVR; n=24 eyes) and nondiabetic controls (n=110 eyes) prior to vitrectomy.
• They were also yielded from 14 eyes of 14 patients with PDR before vitrectomy and from the same 14 eyes before a second vitrectomy for reoperation.
• An estimation was conducted of the levels of MCP-1, IL-6, IL-8, and VEGF via flow cytometry using a cytometric bead array (CBA) assay.

Results

• Prominently higher mean concentrations of vitreal MCP-1, IL-6, IL-8, and VEGF were reported in patients with PDR and PVR (P<0.01).
• Markedly high correlations were observed among the concentrations of MCP-1, IL-6, and IL-8. In contrast, the correlation of VEGF with the other 3 cytokines was lower.
• Among the 14 patients who required reoperation, the mean vitreal concentrations of MCP-1, IL-6, and IL-8 were higher than that at the time of the initial vitrectomy (P<0.01).
• The mean vitreous level of MCP-1, IL-6, and IL-8 in eyes with fibrous proliferation was higher than in those without fibrous proliferation (P<0.05), at the time of the reoperation vitrectomy.
• On the other hand, VEGF in eyes with neovascular glaucoma (NVG) or anterior hyaloidal fibrovascular proliferation (AHFVP) appeared to be higher than in the eyes without NVG and AHFVP (P<0.05).