Abstract

DO.07.02

Pathophysiology of PEX-Syndrome/Glaucoma

Schlötzer-Schrehardt U.
Universitäts-Augenklinik Erlangen

Pseudoexfoliation glaucoma (PEXG) is the most common and most important secondary open-angle glaucoma comprising the majority of glaucoma in some countries. The underlying disorder, pseudoexfoliation syndrome (PEX), is a generalized disease of the extracellular matrix characterized by the progressive, stable deposition of abnormal fibrillar aggregates in various intra and extraocular tissues. Active involvement of trabecular meshwork cells in this fibrotic process involving the local production of PEX material in the juxtacanalicular area may be the primary cause of outflow resistance and chronic pressure elevation in PEX patients. Molecular biologic and biochemical data support the pathogenetic concept of PEX as a type of stress-induced elastosis, associated with the excessive production and abnormal aggregation of elastic fiber components. Recently, a strong genetic risk factor for PEX/PEXG, i.e. polymorphisms in the lysyl oxidase-like 1 (LOXL1) gene, has been identified. LOXL1, a member of the lysyl oxidase family of enzymes, which are essential for the formation, stabilization, and maintenance of elastic fibers, has been shown to play a role in PEX material accumulation and in concomitant elastotic processes in intra- and extraocular tissues of PEX patients. In addition, TGF-b1, increased oxidative and cellular stress, a dysbalance of proteolytic enzymes and their inhibitors, low grade inflammatory processes, and impaired cellular protection mechanisms appear to be key factors in pathogenesis.

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