Abstract
Purpose:
Proliferative diabetic retinopathy (PDR) is associated with microvascular complications that cause biochemical changes in human retina and vitreous and alter the proteome of vitreous humor. The present study investigated the human PDR vitreous proteome with nano-LC-ESI-MS/MS.
Methods:
Vitreous humor of PDR subjects (N=12) who underwent pars plana vitrectomy in University of Florida, Jacksonville Ophthalmology clinic were collected. Subjects who underwent surgery for epiretinal membrane or macular hole served as controls. The protocol was reviewed and approved by institution review board at University of Florida, Jacksonville. Vitreous samples were collected after informed consent and snap frozen on ice. Samples were digested with trypsin and purified using high performance liquid chromatography columns. Purified peptide samples were loaded onto LTQ Orbitrap XL mass spectrometer (ThermoFisher Scientific, West Palm Beach, FL) for LC-MS/MS analysis. Data were analyzed using scaffold version-4 software.
Results:
<br /> A total of 65 proteins were found in vitreous using LC-ESI MS/MS analysis. Thirteen proteins that are participants in coagulation and complement pathway were elevated specifically in PDR vitreous compared to control vitreous proteome. Proteins that are associated with insulin resistance were observed in PDR vitreous but not in control vitreous. Several transporter proteins like serotransferrin, apolipoprotein A-I, A-II, Extracellular cellular matrix proteins and glycoproteins were also noted.
Conclusions:
Detection of elevated coagulation and complement cascade proteins in PDR vitreous compared to normal subject implies dysfunction of these cascades and confirm increased leukostasis and inflammation in PDR.