Large-scale proteomic analysis of aqueous humor from patients with primary open angle and exfoliation glaucoma

A large-scale proteomic approach was used to evaluate the protein profiles of aqueous humor obtained from patients with primary open angle glaucoma (POAG) and exfoliation glaucoma (EXG). The study population consisted of 15 POAG and 15 EXG patients, and 10 patients with no previous ophthalmic treatment as controls. Aqueous humor was collected at the beginning of surgery. Proteins were analyzed using the SOMAscan platform. Among the 7,335 human proteins identified in the aqueous humor of POAG and EXG patients, 215 and 330, respectively, were upregulated, as compared to controls. A pathway-enrichment analysis of the proteins upregulated in both POAG and EXG revealed enrichment of those involved in trabecular meshwork remodeling. Among the 43 and 23 proteins downregulated in POAG and EXG, respectively, was GSTP1, whose null genotype has been shown to increase the risk of POAG in Asians. SOMAscan analysis of the aqueous humor proteins of POAG and EXG patients revealed enrichment of pathways related to the onset and progression of glaucoma, as well as novel disease-associated proteins. These results demonstrate the advantages of SOMAscan, including its high detection sensitivity and accuracy even in analyses of a small number of samples.