MicroRNA-200b Expression in the Vitreous Humor of Patients with Proliferative Diabetic Retinopathy

<b><i>Background:</i></b> The role of microRNA (miRNA)-200b in the pathogenesis of proliferative diabetic retinopathy (PDR) has been studied in diabetic animal models. The aim of this study was to assess miRNA-200b expression in the vitreous of patients with PDR and to determine its correlation with vascular endothelial growth factor (VEGF), one of the pathogenic mechanisms in PDR. <b><i>Methods:</i></b> Quantitative reverse transcription polymerase chain reaction was used to measure miRNA-200b expression in the vitreous from 29 eyes with PDR and 30 eyes with idiopathic macular holes (IMH; control group). Vitreous VEGF was measured using an enzyme-linked immunosorbent assay. <b><i>Results:</i></b> miRNA-200b<b> </b>expression was about 5-fold increased in the vitreous samples from eyes with PDR compared with the controls (<i>p</i> ≤ 0.001). Vitreous VEGF expression was also significantly higher in the PDR group than in the IMH group (<i>p</i> ≤ 0.001), but no significant correlation was found between miRNA-200b and VEGF. <b><i>Conclusion:</i></b> Both miRNA-200b and VEGF are increased in the vitreous of patients with PDR but in a noncorrelated pattern. miRNA-200b may be involved in the pathogenesis of PDR but through VEGF-independent mechanisms. Further studies are needed to identify the miRNA-200b-targeted genes involved in the pathogenesis of PDR and to examine the potential role of miRNA-200b as a target for PDR treatment.