Abstract
Purpose:
Pathogenesis of Age-related Macular Degeneration (AMD) is a complex, poorly understood interaction of multiple factors. We performed a clinical-experimental study to identify potential future biomarkers and new targets of therapy.
Methods:
Vitreous samples of patients with AMD (sample group, n=108) or idiopathic floaters (control group, n=26) were analyzed. Patients with systemic diabetes, nephropathy, uncontrolled hypertension or diabetic retinopathy were excluded. Samples were taken via a 23 gauge single-site core vitrectomy. After tryptic digestion analysis was performed using capillary electrophoresis coupled online to a time-of-flight mass spectrometer, as well as tandem mass spectrometry. Significant peptides were determined by comparing AMD-samples with samples of the controls and then matched to corresponding proteins. Gene Ontology-Terms (GO-Terms) were assigned to every IPI number via WebGestalt (WEB-base Gene SeT AnaLysis Toolkit). Three main categories were formed: Biological Process, Cellular Component and Molecular Function. For statistical analysis Wilcoxon-Mann-Whitney Test was used. A P value of α<0.05 was considered statistically significant.
Results:
In our analysis 878 successfully sequenced peptides were detected, relating to 136 proteins. 50 proteins, composed of 116 peptides, were expressed significantly different between sample and control group (P=3,48E-8 to 4,91E-2). 42 proteins could be analyzed via WebGestalt. In the following most frequent GO-Terms of the three formed main categories are listed. Biological Process: response to stimulus (n=33), multicellular organismal process (33), biological regulation (28). Cellular component: extracellular space (23), membrane-enclosed lumen (17), extracellular matrix (13). Molecular Function: protein binding (26), structural molecule activity (14), enzyme regulator activity (13).
Conclusions:
In this descriptive study we could confirm up- or down regulated proteins in patients with AMD by using one of the highest number of samples in literature. Proteins assigned to the most common GO-Terms may have an important function in the pathogenesis of AMD.