Abstract
Purpose::
Oxidative stress facilitates the deposition of advanced glycation end-products (AGEs) which has been associated with age-related tissue alterations, neurodegenerative and diabetic pathology. In the eye, AGEs have been demonstrated in diabetic retinopathy and in the retina of glaucoma patients. Here, we studied an association of AGEs with alterations of the anterior chamber angle in glaucoma patients by immunohistochemistry.
Methods::
Immunohistochemistry (IHC) for the monoclonal anti-AGE- 6D12 was performed on sections of paraffin-embedded tissues of 26 trabeculectomy specimens from patients with POAG. For comparison, we studied 10 eyes of healthy corneal transplant donors within the same age group, and 12 eyes which had been enucleated because of secondary glaucoma. IHC was performed using the indirect alkaline phosphatase technique. The sections were evaluated in a masked fashion using a semiquantitative scoring system.
Results::
.The trabeculectomy specimens showed varying degrees of fibrosis and a fine pattern of regular dot-like AGE-deposits, (grades 1-2), which was more extensive in 4 cases (grade 3). Eyes with secondary glaucoma showed moderate to extensive deposits (grade 3-4) of AGEs within the anterior chamber angle mostly associated with the basis of the iris and the channel of Schlemm, but only small deposits (grade 1-2) in the superficial trabecular meshwork and in the sclera. In donor eyes the anterior chamber angle remained mostly free of AGEs and the extent of AGE-deposition in the retina was dependent on age.
Conclusions::
We have demonstrated the deposition of AGEs in the anterior chamber angle of patients with glaucoma. The observed pathology was more severe in cases with secondary glaucoma and unfavourable outcome. Our results support the assumption that some of the passage inhibition of aqueous humor in glaucoma may be related to the effects of advanced aging with the possible consequence of altered rigidity within the trabecular meshwork.
Keywords: trabecular meshwork • immunohistochemistry