Proteomic analysis of vitreous from diabetic macular edema

To identify and analyze diabetic macular edema (DME)-related proteins in the vitreous, en masse, using two-dimensional gel (2D gel) electrophoresis and mass-spectrometry (MS). Vitreous samples were corrected from 20 eyes with pre-proliferative diabetic retinopathy associated with DME (DME group) and without DME (non-DME group). They were subjected to 2D gel electrophoresis, and the spot intensities were compared between the groups. Apparently visible spots were excised from the gel, and the proteins were identified by liquid chromatography tandem MS (LC MS/MS) sequence analysis. We identified 14 proteins from the DME group, and 15 proteins from the non-DME group. The intensity of eight spots was markedly higher in DME than non-DME samples and one spot was detected only in non-DME samples. From the eight spots, six proteins were identified, including PEDF, ApoA-4, ApoA-1, Trip-11, PRBP, and VDBP. On the other hand, Apo H was expressed only in non-DME. Certain vitreous proteins expressed exclusively in DME and lacked in DME. These chemical mediators in the posterior vitreous may play a role in the pathogenesis of DME.