Evaluation of Hypoxia and Microcirculation Factors in the Progression of Diabetic Retinopathy.

Purpose: The purpose of this study was to evaluate comparatively the changes in HIF-1ɑ, EPO, sICAM-1, hemodynamic, and electrophysiological parameters during the progression of non-proliferative diabetic retinopathy (NPDR).

Methods: This retrospective longitudinal study included 82 patients with NPDR, who were divided into 2 groups: group I (n = 40) consisted of patients without progression of NPDR after 1 year and group II (n = 42) included patients with the transition of NPDR to proliferative diabetic retinopathy (PDR). The hemodynamics of the eye was assessed by Doppler ultrasonography. The glial hypoxia index Cg was calculated using ERG. The serum levels of hypoxia-inducible factor 1-a (HIF1-α), soluble intercellular adhesion molecule-1 (sICAM-1), and erythropoietin (EPO) were determined by ELISA method.

Results: In group II, resistive index (RI), short posterior ciliary arteries (SPCAs) increased significantly from 0.62 ± 0.005 to 0.65 ± 0.007 (P = 0.003), being higher than the corresponding parameter in group I (P = 0.013). In group II, there was an increase in the hypoxia index Cg (5.56 ± 0.05) relative to the primary indicators and in group I (P < 0.001). In group II, HIF1-ɑ, EPO, and sICAM-1 levels after a year significantly increased (0.213 ± 0.02 ng/mL, 37.7 ± 2.4 mIU/mL, and 576.3 ± 11.9 ng/mL, respectively) both relative to the main indicators and the values in group I (P < 0.001). When EPO exceeds 27.5 mIU/mL, a high risk of progression of NPDR to the initial stages of PDR is predicted.

Conclusions: The glial Cg index and the level of HIF1-a, EPO in the serum of patients with progression of NPDR were initially higher than in patients without progression of NPDR and have increased during the year, indicating the development of PDR due to more severe hypoxia.