Biological Characteristics of Subsilicone Oil Fluid and Differences With Other Ocular Humors.

Hideyuki Shimizu,Takeshi Iwase,Kazuhisa Yamada,Rina Namba,Seina Ito,Yasuki Ito,Shiang-Jyi Hwang,Ayana Suzumura,Keiko Kataoka,Shinji Ueno,Hiroki Kaneko,Yasuhito Funahashi,Hiroko Terasaki,Kei Takayama

doi:10.1167/tvst.8.1.28

Abstract

PurposeSubsilicone oil fluid (SOF) in eyes with silicone oil (SO) endotamponade possibly has a role in complications (e.g., vision loss); thus, we aimed to examine inflammatory cytokine and electrolyte levels and retinal glial cell viability in SOF.MethodsWe measured major inflammatory cytokine levels and electrolytes in SOF and compared them with those in vitreous fluid (VF) and anterior chamber fluid (ACF). We analyzed the correlation between inflammatory cytokines and retinal thickness in SO-filled eyes. Further, we measured the MIO-M1 cell viability in medium with SOF and compared it with that containing VF.ResultsWe collected and examined 57 SOF, 22 ACF, and 21 VF samples from eyes with PVR, PDR, RD, and MH. Interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1 levels in SOF were significantly higher than those in ACF. There was no significant difference for all cytokines between SOF and VF. Retinal thickness changes during SO endotamponade were not correlated with the presence of any inflammatory cytokines. Levels of ferrous iron, but not of potassium, showed a significant decrease in SOF compared with VF. The WST-1 assay showed that SOF-added medium induced higher MIO-M1 cell viability than VF-added medium.ConclusionsWe found no significant correlation between the change in the retinal thickness and cytokine levels, but SOF contains higher concentrations of cytokines and lower concentrations of ferrous iron and can be biologically distinguished from ACF and VF.Translational RelevanceNovel knowledge of inflammatory cytokine levels and electrolytes in SOF provides better understanding of pathology of SO-filled eyes.

Highlights

Silicone oil (SO) is a major surgical adjuvant during retinal surgeries
We could not find specific causes for SO-related vision loss (SORVL) in SO-filled eyes. We designed this new study seeking to explain SORVL and SO-related retinal changes biologically, and we further examined the association between retinal thickness and cytokine level changes, and the cytokine level differences among subsilicone oil fluid (SOF), anterior chamber fluid (ACF), and vitreous fluid (VF) in SO-filled eyes with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), or retinal detachment (RD)
We froze SOF, ACF, and VF and thawed them only once before applying the MILLIPLEX MAP Human Cytokine/Chemokine Panel (Merck Millipore, Billerica, MA), a bead-based multiplex immunoassay that allows the simultaneous quantification of the following human cytokines: fibroblast growth factor (FGF)-2, interferon (IFN)-c, interleukin (IL)[10], IL-12p40, IL-1b, IL-6, IL-8, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor (TNF)-a, and vascular endothelial growth factor (VEGF)

Summary

Introduction

Silicone oil (SO) is a major surgical adjuvant during retinal surgeries. SO, from a vitrectomy with SO tamponade, is evacuated after the retina has attached or the condition has stabilized, usually weeks to months after the primary surgery.[5,6] During the evacuation, a certain amount of fluid in the space between SO and the surface of the posterior retina can be found in the eye We have dubbed this fluid ‘‘subsilicone oil fluid (SOF)’’ and have hypothesized that inflammatory cytokines in it have pivotal roles in SORVL induction.[7] We have proposed a safe method to extract this SOF and have examined the levels of major inflam-

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