Abstract
Abstract: :
Purpose: Age–related macular degeneration (AMD) is the leading cause of blindness for the elderly. Recently, a considerable amount of evidence has accrued which would link AMD to the inflammatory process. PAF is the most potent proinflammatory lipid mediator described and is produced by various cell types, including platelets, neutrophils, monocytes/macrophages, endothelial cells and the retina. It has been well established that PAF is involved in number of disease processes, including asthma, sepsis, cardiac infarction, cerebral ischemia, hypertension, gastric ulceration, etc. We have therefore examined the expression of PAF receptors in human eyes and tissue cultured retinal pigment epithelial (RPE) cells in an attempt to determine the feasibility of a possible pathogenic role of PAF in development of AMD. Methods: Paraffin slides of human eyeballs from five different individuals were obtained from Parkland Memorial Hospital Pathology Lab. These slides were deparaffinized, bleached and underwent immunohistology staining. They were treated with goat anti–human PAF–R mono–clone antibody (2ug/ml). Human retinal pigment epithelial cells were obtained from ATCC and maintained in Hank’s balance salt solution. The cultured RPE cells were detached with EDTA and stained with goat–anti human PAF–R antibody followed by mouse anti–goat antibody conjugated with FDIC (1ug/ml). The expression of PAF–R was analyzed by flow cytometry. The RPE cells treated with goat IgG isotope plus mouse anti–goat antibody conjugated with FPIC were used as negative controls. Results: PAF–R was present in all five eyes we have tested. No PAF receptor was detected in negative controls. PAF–R was expressed exclusively in RPE cells, ciliary body epithelial cells and Bruch’s membrane. By using tissue cultured cells, more than 59% of RPE cells expressed PAF–R, compared with only 14 % on IgG isotope controls. Conclusions: The PAF receptor is presented on human RPE and Bruch’s membrane. The function of such expression merits further investigation. PAF and PAF–like compounds may play a pathogenic role in the development of AMD.
Keywords: age-related macular degeneration • retinal pigment epithelium