Protein Composition of the Subretinal Fluid Suggests Selective Diffusion of Vitreous Proteins in Retinal Detachment.

Ebbe Toftgaard Poulsen,Goran Petrovski,Anders K Hansen,Xhevat Lumi,Jan J Enghild

doi:10.1167/tvst.9.11.16

Ebbe Toftgaard Poulsen, Goran Petrovski + Show 3 more

Open Access

https://doi.org/10.1167/tvst.9.11.16

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Abstract

PurposeTo study the proteome of the subretinal fluid (SRF) from rhegmatogenous retinal detachment (RRD) in search for novel markers for improved diagnosis and prognosis of RRD.MethodsHuman undiluted SRF obtained during vitrectomy for primary RRD using a 41-gauge needle (n = 24) was analyzed and compared to vitreous humor from 2-day postmortem eyes (n = 20). Sample preparation underwent nanoflow liquid chromatography–tandem mass spectrometry. Label-free quantification (LFQ) using MaxQuant was used to determine differentially expressed proteins between SRF and vitreous humor. The intensity-based absolute quantification (iBAQ) was used to rank proteins according to their molar fractions within groups. Identification of proteins beyond the quantitative level was performed using the Mascot search engine.ResultsThe protein concentration of the control vitreous humor was lower and more consistent (1.2 ± 0.4 mg) than that of the SRF (17.9 ± 22 mg). The iBAQ analysis showed high resemblance between SRF and vitreous humor, except for crystallins solely identified in vitreous humor. The LFQ analysis found 38 protein misregulations between SRF and vitreous humor of which the blood coagulation pathway was found to be enriched using the PANTHER Classification System. Combined, the iBAQ, LFQ, and Mascot analysis found an overlap only in chitinase-3-like protein 1 and galectin-3-binding protein unique to the SRF.ConclusionsThe proteome of the SRF was highly represented by proteins involved in proteolysis. Such proteins can possibly serve as targets in modulating the effects of SRF in RD.Translational RelevanceTo identify potential novel biomarkers for therapeutic targeting in RD.

Highlights

Rhegmatogenous retinal detachment (RRD) is the most common vision-threatening retinal condition requiring urgent care
The intensity-based absolute quantification (iBAQ) analysis showed high resemblance between subretinal fluid (SRF) and vitreous humor, except for crystallins solely identified in vitreous humor
The proteome of the SRF was highly represented by proteins involved in proteolysis

Summary

Introduction

Rhegmatogenous retinal detachment (RRD) is the most common vision-threatening retinal condition requiring urgent care. With its relatively high incidence of 1:10,000 to 15,000 per year, RRD affects mostly the elderly population as well as those in their mid/late working age.[1,2] Delayed or improper surgical treatment of patients in the acute phase of the disease can cause severe to permanent visual impairment. RRD can be described by two main cellular mechanisms: inflammation and cell death. The inflammation is sterile without any presence of infection. Fresh detachment is hallmarked by the presence of hyperreflective points on optical coherence tomography at the detached neuroretina/retinal pigment epithelium (RPE) border, which at later stages likely contain aggregates of macrophages or activated microglia (CD68+ C34−) at this cellular interface.[3] Vitreoretinal traction plays a role in RRD by allowing accumulation of liquefied vitreous under the retina, leading

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