Aqueous cytokine and growth factor levels indicate response to ranibizumab for diabetic macular oedema

Background/Aims

To investigate the relations between aqueous humour levels of cytokines/growth factors and treatment response to intravitreal ranibizumab (IVR) for diabetic macular oedema (DME)

Methods

Sixty-eight eyes of 68 patients with treatment-naïve centre-involved DME, central macular thickness (CMT) greater than 400 μm and visual acuity (VA) worse than logMAR 0.3 were recruited. Each patient received monthly IVR injection (0.5 mg/0.05 mL) until CMT was reduced to below 300 μm. Additional IVR was given to maintain CMT below 300 μm during the clinical course of 6 months with monthly follow-up. Aqueous concentrations of cytokines/chemokines and growth factors were measured using samples obtained just before first IVR injection. CMT and VA were monitored monthly for up to 6 months. The number of monthly IVR injections given during the 6-month study period was also recorded.

Results

Twenty-four eyes showed CMT <300 μm soon after the first IVR injection (good responders), while 12 eyes did not reach the goal after six consecutive injections (poor responders). Baseline CMT and VA were not significantly different between the two groups. However, the good responders showed significant increases in baseline aqueous concentrations of vascular endothelial growth factor (VEGF), placenta growth factor, soluble VEGF receptor-1 (sVEGFR1), monocyte chemoattractant protein-1, intercellular adhesion molecule-1, interleukin 6 and inducible protein-10, but not of sVEGFR2, compared with poor responders.

Conclusions

Response to ranibizumab treatment for DME appears to be associated with aqueous concentrations of VEGFR1 family and certain inflammatory cytokines, but not with clinical parameters.

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