Abstract
Purpose: :
Recent studies have illuminated the Vitreous Proteome as a potentially important diagnostic tool that will predict disease progression and response to treatment in eyes with retinal disease. Several studies to date have demonstrated correlations of protein levels between vitreous and aqueous humor, suggesting the measurement of aqueous humor protein levels can replace the need to measure these levels in vitreous. In contrast to previous studies that analyzed only a few endpoints (VEGF, IL-6), this study further analyzed the relationship between aqueous and vitreous by probing a wide array of proteins in patients with posterior segment diseases. Targeted proteins in the current study belong to a wide group of families known to be active in ocular disease including angiogenesis/growth, inflammation, apoptotic and complement pathways.
Methods: :
Anterior chamber aqueous fluid was obtained (0.05 mL) using a limbal approach with a 30 gauge needle. Immediately following successful aqueous fluid sample, the vitreous sample was obtained via a pars plana approach. A 25 gauge needle with a 1 mL syringe was directed into the mid-vitreous cavity and 0.05 to 0.10 mL of vitreous fluid was gently aspirated. Aqueous and vitreous samples were then analyzed via reverse phase protein microarray technology (RPPM).
Results: :
The entire sample population (n=11) was investigated via RPPM for 34 proteins. This process revealed eight proteins that significantly correlated between the vitreous and aqueous humor. Eight proteins had positively trending correlations but fell short of significant correlations, while 23 proteins had absolutely no correlation.
Conclusions: :
Proteins in the aqueous cannot be assumed to correlate with their counterparts in the vitreous. Expanded studies are needed to analyze the relationship between anterior and posterior chamber levels of proteins in patients with diverse diseases. Given the findings in this study, new techniques that allow safe in-office collection of vitreous samples will add to the ability to understand the Vitreous Proteome and manage retinal diseases.
Keywords: retina • vitreous • proteomics