Effects of ranibizumab on growth factors and mediators of inflammation in the aqueous humor of patients with diabetic macular edema.

PURPOSE

The study aims to investigate changes in the aqueous humor levels of 8 growth factors and inflammatory mediators after intravitreal ranibizumab injection (IRI) and the relationship between these substances and functional-morphological parameters in patients with diabetic macular edema (DME).

METHODS

We recruited 25 patients with DME who were scheduled to receive 2 doses of IRI at monthly intervals. At baseline and 1 month after IRI, we measured aqueous levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), monocyte chemoattractant protein 1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), platelet-derived growth factor (PDGF)-AA, interleukin (IL)-6, IL-8, and interferon-gamma inducible protein 10 (IP-10) by the suspension array method. Central macular edema (CMT) or macular volume (MV) was examined by optical coherence tomography before and 1 month after IRI, and the improvement of macular edema was evaluated by calculating the percent change of CMT or MV.

RESULTS

Aqueous humor levels of VEGF, PlGF, PDGF-AA, and IP-10 were significantly decreased 1 month after IRI (P < 0.001, P = 0.002, P = 0.002, and P = 0.005, respectively). In addition, the baseline aqueous humor levels of PlGF, MCP-1, and IL-6 were significantly correlated with the improvement in best corrected visual acuity (P = 0.036, P = 0.024, and P = 0.049, respectively). The baseline aqueous humor level of sICAM-1 was significantly negatively correlated with the change in CMT (P = 0.005), and the baseline aqueous humor levels of VEGF and PlGF were significantly correlated with the change in MV (P = 0.020 and P = 0.003, respectively). Furthermore, the percentage reduction in VEGF after IRI was significantly correlated with the change in MV (P = 0.037).

CONCLUSIONS

Our findings suggest that the change in aqueous humor levels of VEGF, PlGF, and ICAM-1 in DME may not only be an anatomic response but also a potential therapeutic target.

CLINICAL TRIAL REGISTRATION

This study was registered in the University Hospital Medical Information Network (UMIN) clinical trial registry. The registration number is UMIN000030301.