Abstract
Purpose: :
Diabetic Retinopathy (DR) is the major cause of vision loss and blindness in people with diabetes, and the commonest cause of loss of vision in the working population. Many people with diabetes do not undergo regular retinal checks as recommended. An objective test that distinguished patients who had significant retinal disease from those who did not require ophthalmic assessment would allow screening and treatment programs to be more effectively targeted. The identification of disease biomarkers may also lead to insights into the pathogenesis of DR that might result in new treatments to prevent and even reverse loss of vision from DR. We have taken a proteomic approach to compare the changes in the protein profile of plasma from sufferers of DR with non-diabetic plasma in order to identify potential biomarkers of this disease.
Methods: :
Plasma samples were prepared for proteome analysis by depleting six highly abundant plasma proteins human serum albumin, antitrypsin, IgG, IgA, haptoglobin and transferrin (Agilent MARS 6) then digesting the depleted sample with trypsin. Tryptically digested peptides were labelled with isobaric mass spectrometry (MS) based quantitative tags, iTRAQ (Applied Biosystems, CA, USA), analysed using nano LC MS/MS, and relative protein quantification obtained using Protein Pilot software (Applied Biosystems).
Results: :
A number of proteins from diabetic plasma samples were identified to be significantly differentially expressed. Proteins including complement C3 precursor, fibronectin and apolipoprotein B-100 were found to be up-regulated in plasma from diabetic samples with varying severity of DR. Complement C4-A, complement C4-B, Apolipoprotein A-1 and alpha-2-macroglobulin were down regulated in diabetic plasma samples.
Conclusions: :
The application of highly sensitive quantitative proteomics technology to DR plasma can provide information on potential biomarkers for DR.
Keywords: diabetic retinopathy • proteomics • retina