Abstract
Abstract: :
Purpose:To determine whether the distribution and post–translational modification of proteins in human vitreous fluid alters with location and age. Methods:Donor eyes of two age groups, younger than 20 years and older than 60 years, were snap frozen within 6 hours post–mortem and stored at –70 C until analysis. The frozen vitreous was separated into six segments comprised of three anterior and three posterior sections, centrifuged, and dialyzed extensively to remove salts. Two dimensional gel electrophoresis with colloidal coomassie or silver staining was used to separate and visualize the proteins. The gel spot patterns were analysed by Progenesis image analysis software and selected protein spots were analysed by MALDI–MS or ESI–MS/MS. Results:Several hundred protein spots were visible within each section of the vitreous. Dominant plasma–derived proteins including albumin, transferrin and transthyretin are present in all sections from each age group. Significant differences in the relative spatial abundance of transferrin, retinoic acid binding protein, and transthyretin post–translational modifications have been noted. The presence of over 30 protein spots in the molecular weight range of 10–50 kDa alters significantly dependent upon anterior or posterior vitreous humor location. Conclusions:The distribution of numerous vitreous humor proteins is spatially dependent. The abundance of the dominant plasma derived proteins does not appear to alter with age.
Keywords: vitreous • aging • proteomics