Abstract
Purpose :
Sampling of aqueous humor in eyes with retinoblastoma is now done during injection of intravitreal melphalan. This gives access to the intraocular fluid of these eyes in a way that was not previously possible. The aim of this study is to evaluate the aqueous humor from eyes with retinoblastoma for the presence of nucleic acids, including DNA, RNA and micro-RNA. A secondary aim is to evaluate for changes in the nucleic acid content during treatment.
Methods :
Eighteen samples of aqueous humor (100 ul) from 8 patients were evaluated for the presence of DNA, RNA and micro-RNA. Aqueous from 6 patients were sampled routinely as part of the procedure to inject melphalan intravitreally as treatment for seeding. Aqueous from 2 additional patients was taken after primary enucleation for treatment of advanced, unilateral retinoblastoma. DNA, RNA and micro-RNA were assayed using Qubit HS kits (ThermoFisher scientific) specific for each nucleic acid.
Results :
DNA, RNA and micro-RNA were assayed in all 18 samples, with mean concentrations (range) of 5.1 ng/ul (0.084-56 ng/ul), 1.7 ng/ul (0.4-12.8 ng/ul), and 17.1 ng/ul (0.079-150 ng/ul), respectively. Including all patients (intravitreal injection and primary enucleation) micro-RNA was found to have the highest concentration in the aqueous as compared to RNA and DNA. Aqueous humor samples from patients treated with primary enucleation had the highest concentration of all nucleic acids as compared to those from patients undergoing treatment with intravitreal melphalan, and micro-RNA was the most abundant. Aqueous humor samples from patients treated with intravitreal injection had the following mean concentrations (range) of DNA, RNA and micro-RNA respectively 0.33 ng/ul (0.084-0.77 ng/ul), 0.80 ng/ul (0.4-4.23 ng/ul), and 0.54 ng/ul (0.079-1.82 ng/ul), respectively There was no significant decrease in the level of nucleic acids after subsequent intravitreal injections. There was a significant difference between DNA and RNA in the samples (p=0.009) however not between the other nucleic acids assayed.
Conclusions :
The aqueous humor of eyes with retinoblastoma harbor DNA, RNA and micro-RNA. The highest concentration of nucleic acid assayed is micro-RNA. Eyes that were primarily enucleated had the highest concentration of all nucleic acids. During active treatment for seeding however, the concentration of nucleic acids was not found to decrease after each sequential injection.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.