Identification of Diagnostic and Prognostic microRNAs for Recurrent Vitreous Hemorrhage in Patients with Proliferative Diabetic Retinopathy

MicroRNAs (miRNAs) can provide insight into the pathophysiological states of ocular tissues such as proliferative diabetic retinopathy (PDR). In this study, differences in miRNA expression in vitreous from PDR patients with and without incidence of recurrent vitreous hemorrhage (RVH) after the initial pars-plana vitrectomy (PPV) were analyzed, with the aim of identifying biomarkers for RVH. Fifty-four consented vitreous samples were analyzed from patients undergoing PPV for PDR, of which eighteen samples underwent a second surgery due to RVH. Ten of the sixty-six expressed miRNAs (miRNAs-19a, -20a, -22, -27a, -29a, -93, -126, -128, -130a, and -150) displayed divergences between the PDR vitreous groups and to the control. A significant increase in the miRNA-19a and -27a expression was determined in PDR patients undergoing PPV as compared to the controls. miRNA-20a and -93 were significantly upregulated in primary PPV vitreous samples of patients afflicted with RVH. Moreover, this observed upregulation was not significant between the non-RVH and control group, thus emphasizing the association with RVH incidence. miRNA-19a and -27a were detected as putative vitreous biomarkers for PDR, and elevated levels of miRNA-20a and -93 in vitreous with RVH suggest their biomarker potential for major PDR complications such as recurrent hemorrhage incidence.

Change of Vascular Endothelial Growth Factor Levels following Vitrectomy in Eyes with Proliferative Diabetic Retinopathy

Purpose. To study the change of concentrations of vascular endothelial growth factor (VEGF) in vitreous cavity after vitrectomy in eyes with proliferative diabetic retinopathy (PDR). Methods. In this retrospective study, intravitreal fluid samples were taken at baseline (beginning of the vitrectomy) and postoperatively (several days later after vitrectomy) at the time of prophylactic injection of bevacizumab in forty-eight eyes of forty-eight patients with PDR. Postvitrectomy fluid samples were divided into four groups according to the time interval between the vitrectomy and the injection (group 1, 3–5 days; group 2, 6–10 days; group 3, 11–15 days; group 4, 16–21 days; twelve eyes in each group). Postvitrectomy fluid sample was paired with baseline sample for each eye. VEGF concentrations in the samples were determined by enzyme-linked immunosorbent assay. Recurrent vitreous hemorrhage and neovascular glaucoma within six months postvitrectomy were also analyzed. Results. Overall, the intravitreal VEGF level after vitrectomy (median, 36.95 pg/ml; range, 3.2–1,299.4 pg/ml) was significantly less than the VEGF level at baseline (median, 704.5 pg/ml; range, 30.6–1,981.1 pg/ml). Postoperative and baseline VEGF levels were significantly correlated (r = 0.499, p<0.01). Both the absolute value of postoperative VEGF concentrations and the postop/baseline VEGF ratios declined with time and dramatically decreased in groups 3 and 4. In only two eyes, the postoperative VEGF level was even higher than the baseline VEGF level (postop/baseline VEGF ratio >1), and recurrent vitreous hemorrhage developed within six months in these two eyes. Conclusions. After vitrectomy for PDR, intravitreal VEGF levels decreased substantially in the majority of patients, while persistent high-VEGF level occurred in a few individuals. Postoperative VEGF levels and postop/baseline VEGF ratio declined with time. The postop/preop VEGF ratio may serve as a predictor for late complications.

Surgical Treatment of Diabetic Recurrent Vitreous Hemorrhage and Traction Retinal Detachment

Although the irreversible proliferative complications of diabetes are less visible with anti-vascular endothelial growth factor (anti-VEGF) agents, surgical treatment is still important for these groups of patients; because of the high frequency of diabetes mellitus. The most common indications for vitreoretinal surgery for proliferative diabetic retinopathy are vitreous hemorrhages and tractional retinal detachments. This review summarized the surgical treatment of these two complications.

Intravitreal Bevacizumab for Proliferative Sickle Retinopathy: A Case Series

Purpose: To report outcomes of intravitreal bevacizumab therapy for proliferative sickle retinopathy (PSR). Methods: A retrospective, interventional case series. Five eyes of 5 patients with PSR were managed with intravitreal bevacizumab therapy over a 13-year period at a single institution. Results: Four patients had sickle cell-hemoglobin SC disease and 1 had sickle cell-beta thalassemia disease. Four of the patients treated with intravitreal bevacizumab injection were treated for recurrent vitreous hemorrhage and 1 was treated for new peripheral sea fan neovascularization. In those patients treated for vitreous hemorrhage, there was improvement in visual acuity as early as 2 weeks after treatment. Only 2 of the patients had documented recurrent vitreous hemorrhage during the period of follow-up after the initial injection. In 1 patient, the vitreous hemorrhage did not recur until 13 months after the injection. All patients showed an anatomic response to intravitreal bevacizumab therapy with partial regression of the peripheral sea fan neovascularization. All patients tolerated the injections without any complications. Conclusions: Intravitreal bevacizumab injections appear to be well tolerated and may be an effective treatment of PSR. Regression of peripheral sea fan neovascularization and decreased duration of vitreous hemorrhage may be observed. Large-scale randomized controlled trials are needed to further clarify the role of bevacizumab in PSR.