Abstract
Purpose: :
Fuchs endothelial corneal dystrophy (FECD) is a disorder characterized by the abnormal progressive loss of corneal endothelial cells (CECs). Until now, the mechanism of the disease process has not been enlightened. Oxidative stress and inflammatory mechanisms are hypothesized to be involved in the disease process. The receptor of advanced glycated endproducts (RAGE) is involved in several inflammatory and degenerative diseases. Interaction of RAGE ligands with the receptor increase oxidative stress and modulate apoptosis. RAGE and its ligands S100B and HMGB-1 may be involved in FECD. Therefore, we evaluated the expression of the receptor of RAGE and its ligands S100B and HMGB1 in FECD.
Methods: :
Cryopreserved corneal tissue of 6 patients with FECD were used for the immunohistochemical detection of the RAGE receptor system and its ligands S100B and HMGB-1. Briefly, 10µM thick sections were used for the immunohistochemical procedure. After quenching the endogenous peroxidase, the sections were blocked with a 2% albumin solution in phosphate buffered saline. After this blocking procedure, the sections were incubated overnight at 4O Celsius with the desired antibodies (RAGE, S100B, HMGB1). After this incubation procedure, the sections were exposed to the appropriate biotinylated secondary antibody (dilution 1:200). Sections were incubated with the avidin-conjugated horseradish peroxidase (Vector Laboratories) and peroxidase activity was developed with a peroxidase substrate solution.
Results: :
All sections showed a strong expression of RAGE in the endothelial layer of the cornea. No expression of S100B was seen. In contrast, the growth factor HMGB1 was expressed in the keratocytes of the corneal stroma.
Conclusions: :
RAGE and its ligands seem to be of importance for the disease process of FECD. Cell culture studies need to be performed with keratocytes and corneal endothelial cells to discover the effects of HMGB1 on the cellular level of the cornea.
Keywords: cornea: basic science • growth factors/growth factor receptors • immunohistochemistry