Relationship Between Aqueous Humor Levels of Cytokines and Axial Length in Patients With Diabetic Retinopathy.

Purpose: A negative relationship between intraocular vascular endothelial growth factor-A (VEGFA) and axial length was found, which may help explain why myopia with long axial length was a protective factor for development of diabetic retinopathy (DR). The aim of this study is to further assess the relationship between the aqueous humor levels of interlukin (IL)-8, IL-10, VEGFA, vascular adhesion molecule-1 (VCAM-1), basic fibroblast growth factor, VEGFB, and placental growth factor (PLGF) and axial length in eyes with DR.

Design: Retrospective, single-center, unmasked study.

Methods: Patients with age-related cataract and with/without DR who visited the Department of Ophthalmology at the Affiliated Hospital of Inner Mongolia Medical University were enrolled. The level of IL-8, IL-10, VEGFA, VCAM-1, and basic fibroblast growth factor were measured by cytometric bead array, and VEGFB and PLGF were measured by enzyme-linked immunosorbent assay. Axial length was measured by biometry.

Results: Totally 65 eyes of 65 patients were enrolled, including 14 patients with nonproliferative diabetic retinopathy, 16 patients with proliferative diabetic retinopathy (PDR), and 35 patients with age-related cataract as control. In the nonproliferative diabetic retinopathy group, the aqueous level of PLGF was negatively correlated with axial length (r = -0.576, P = 0.031), whereas the aqueous levels of IL-10 (r = 0.533, P = 0.049) and VCAM-1 (r = 0.566, P = 0.035) were positively correlated with axial length. In the proliferative diabetic retinopathy group, all cytokines did not significantly correlate with axial length.

Conclusions: Among patients with diabetic retinopathy, we further found that aqueous levels of PLGF were negatively correlated with axial length, whereas VCAM-1 and IL-10 were positively correlated with axial length. These findings may suggest that these cytokines play a role in the development of DR, and further explain the relationship between the axial length and DR.