Evaluation of sFLT1 Protein Levels in Human Eyes with the FLT1 rs9943922 Polymorphism

Abstract

Purpose

Age-related macular degeneration (AMD) is a devastating disease characterized by central vision impairment in individuals with advanced age. Neovascular AMD is a form of end-stage disease in which choroidal vessel outgrowth occurs beneath the retina. While many hypotheses have been raised as to what triggers the formation of pathologic choroidal neovascular membranes, the exact mechanism for their initiation remains unresolved. Polymorphisms in the FLT1 gene have previously been associated with neovascular AMD risk, including the rs9943922 SNP. Here, we aimed to determine the association between the high-risk FLT1 genotype and FLT1 protein levels in human retina or RPE/choroid tissue.

Methods

Retina and RPE/choroid tissue from ten human donor eyes was selected from a collection of eyes genotyped for the rs9943922 SNP. Differences in soluble and membrane bound FLT1 protein levels were assessed for retina versus RPE/choroid donor tissue using ELISA and Western blotting analyses. Genotype-associated changes in FLT1 protein levels were also evaluated.

Results

We found soluble FLT1 levels in the RPE/choroid tissue to be approximately three times higher than that of the retina (p<0.001), while both samples have similar levels of the membrane bound form. When tissue with the rs9943922 SNP was compared with controls, no significant genotypic difference in FLT1 protein levels were observed.

Conclusions

Based on these data, we conclude that the rs9943922 SNP in the FLT1 gene does not result in a large difference in FLT1 protein levels, regardless of whether it is the soluble or the membrane bound form.