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Kumar Sambhav, Bharani k Mynampati, K V Chalam, sandeep Grover; Reduction of Aqueous Levels of VEGF After Sequential Intravitreal Injections of Aflibercept in Diabetic Macular Edema. Invest. Ophthalmol. Vis. Sci. 2017;58(8):942.
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© ARVO (1962-2015); The Authors (2016-present)
To measure the aqueous levels of vascular endothelial growth factor (VEGF) after each intravitreal injection of aflibercept in patients with diabetic macular edema (DME).
14 eyes of nine patients with non-proliferative diabetic retinopathy (NPDR) and center-involving DME were included in the study. All the patients had well controlled type 2 diabetes for more than 5 years. All these patients received a course of 3 intravitreal injections of an anti-VEGF agent, aflibercept, 4-6 weeks apart. At each visit, before the injection of intravitreal aflibercept 2mg/0.05 ml, 80-100 µl of aqueous was removed to balance the intraocular pressure. These samples were rapidly cooled on ice, centrifuged to remove cells, and immediately stored in a −80°C freezer. At the time of measurement, the aqueous samples were thawed at room temperature and VEGF levels (pg/ml) were measured using standard Luminex 100 IS fluoroanalyzer (Luminex Inc., Austin, TX, US) method. To ensure a proper assay, a known concentration of human recombinant VEGF was included in each run as a positive control.
The aqueous VEGF level was measured before and after treatment with 2 doses of intravitreal aflibercept. GraphPad InStat v.3; (San Diego, California, USA) was used for statistical analyses. The mean, standard deviation (SD), and median were calculated for aqueous VEGF levels at baseline (1 month after the first injection), 1 month (1 month after the second injection) and 2 months (1 month after the third injection). Non parametric one-way ANOVA (Kruskal-Wallis) was used to compare the mean values of aqueous VEGF levels for each visit.The mean baseline anti-VEGF levels were 47.26 pg/ml [median 26.2; range 6.8-140.8]. The mean anti-VEGF levels at 4-6 weeks visit were 8.05 pg/ml [median 5.5; range 2-18.8] and at 8-12 weeks visit were 5.07 pg/ml [median 4; range 1.48-10.4]. Kruskal-Wallis test results showed statistically significant decrease in VEGF levels on comparing baseline visit to 4-6 weeks follow up visit (p<0.0001) and 8-12 week follow up visit (p=0.0008).
Aqueous concentrations of VEGF in patients with non-proliferative diabetic retinopathy and diabetic macular edema significantly decreases after treatment with intravitreal aflibercept. In the future, the measurement of VEGF levels in aqueous at every visit can possibly be used as a guide to plan treatment at an individual level.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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