Duration 5min, Q&A 3min
Detection of Glaucoma-Related Circulating miRNAs in Aqueous Humor with a Microarray System
Circulating Micro RNAs (miRNAs) in body fluids are thought to be a valuable potential source of novel biomarkers and therapeutic targets. The aqueous humor (AH) is one such fluid in which bacteria, cytokines, and chemokines are often analyzed when diagnosing ocular disease. In this study, a microarray system able to detect 2019 mature miRNAs, was used to analyze individual AH samples from patients with glaucoma, cataracts, and epiretinal membrane, in order to reveal the number of detectable miRNA types and glaucoma specific expression characteristics in the AH.
This research was conducted in accordance with the Declaration of Helsinki and Tohoku University Medical School Institutional Review Board approved the protocol. Informed consent was obtained from 10 glaucoma, 5 cataract, and 5 epiretinal membrane patients undergoing surgery at Tohoku University Hospital, Sendai, Miyagi, Japan. These patients met the inclusion criterion of having had no history of cancer, asthma, and other ocular diseases.
Approximately 100 μl of AH was collected from each patient by anterior chamber paracentesis, using a 30-gauge needle inserted through the peripheral cornea. The needle did not contact any iris or lens tissue during the sampling. Samples were subsequently centrifuged for 10 min at 300 g for removing cellular components, and the total RNA in its aqueous phase was purified with miRNeasy Mini Kit (Qiagen, Valencia, CA). And fraction of small RNAs (<200 nucleotides) was conformed by Agilent 2100 bioanalyzer (Agilent teqnology). AH miRNA samples were hybridized to 3D-Gene human miRNA ver. 1.60 chips containing 2019 miRNAs (Toray Industries, Inc., Tokyo, Japan).
Results and Conclusion
Among the 2019 miRNAs tested, 500.0 ± 188.7 and 561.0 ± 215.5 were present in the AH of the glaucoma and control groups, with no significant difference between them (P = 0.51, Student t-test). The number of miRNAs detected in all glaucoma and all control patients were 158 and 135, respectively. 121 of these miRNAs were detected in all patients from both groups. In these three groups of commonly detected miRNAs, several up and down-regulated miRNAs of glaucoma were found that showed a significant difference (P < 0.05). Most of these miRNAs showed an area under the curve greater than 0.70 in a receiver operating characteristic analysis, and formed a cluster composed only of glaucoma patients in a hierarchal cluster analysis. These are potential candidate miRNA markers for glaucoma.
[ Keyword ]
Circulating miRNA, Aqueous humor, Glaucoma
[ Conflict of Interest ]