Abstract
Purpose:
Primary vitreoretinal lymphoma (PVRL), a subset of primary CNS lymphoma, affects the retina, vitreous, and optic nerve head, with the most common symptoms of blurred or decreased vision. Because the clinical appearances overlap heavily with inflammatory and infectious uveitis, PVRL is often masqueraded as uveitis and treated initially with corticosteroids, which may further mystify the physicians. Recently, studies have unveiled the high stability of miRNA in biofluids and the correlation of miRNA expression profiles with diseases and disease states, which have positioned extracellular miRNA quantification in biofluids as a promising tool for diagnostic applications.
Methods:
The study included 11 B-cell PVRL and 13 uveitis patients. Vitreous specimens were obtained through a standard three port pars plana vitrectomy. The diluted and undiluted vitreous supernatant was pooled and subjected to total RNA extraction using a commercial column-based system (Qiagen miRNeasy® Mini Kit). cDNA was synthesized by using mature miRNA as templates with miRCURY LNA™ Universal RT cDNA Synthesis Kit (Exiqon A/S). Six selected samples (PVRL n=3, uveitis n=3) were arrayed by a RT-PCR-based microRNA panel that detects 168 human mature miRNAs. The markers promising in distinct levels between uveitis and lymphoma were further tested by individual RT-PCR analysis.
Results:
Of 168 human mature miRNAs assayed by RT-PCR array, 29.8% (50 miRs) were detectable in vitreous samples. The miR-484, miR-197, and miR-132 were consistently higher in the PVRL vitreous, while miR-155, miR-200c, and miR-22* consistently higher in the uveitis vitreous. The results were normalized by different combination of 7 control miRs (miR-103, miR-191, miR-42-5p, miR-16, miR-425, miR-93 and miR-451) as recommended by the manufacture. After optimization, the normalization against miR-16 showed equally reliable as the average of 7 control miRs. Individual assay for the selected miRs did not succeed in other 18 samples but the results support the pattern yielded from the array analysis.
Conclusions:
Mature miRs are detectable in vitreous samples. B-cell PVRL and uveitis might be characterized with distinct miR signatures. Assay of selected miR might be helpful in the differential diagnosis of these two diseases. Further investigation on disease miR may provide new insight into ocular lymphoma and uveitis.
Keywords: 535 gene microarray •
746 uveitis-clinical/animal model •
763 vitreous