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Abstract #15975 Published in IGR 2-3
Importance of trabecular meshwork changes in the pathogenesis of primaryopen-angle glaucoma
Lutjen-Drecoll EJournal of Glaucoma 2000; 9: 417-8
in this guest editorial, Elke Lutjen-Drecoll discusses trabecular meshwork changes. Historically the first description of changes in the angle was in 1972 by Rohen and Witmer: the so-called "plaque-material" in the subendothelial region of Schlemms Canal. Morphologically one can find an increase in extracellular material in the subendothelial region of Schlemms Canal, a reduction in cellularity in the trabecular meshwork and changes in the expression of different proteins in the TM cells. The question is whether such changes are the initial events that cause increased pressure or not. The author describes the results of a large study of 45 donor eyes with either primary open angle glaucoma or pseudo-exfoliation. In the eyes with pseudo-exfoliation there was a significant correlation between the amount of PEX-material and IOP on the one hand and with nerve fiber loss on the other hand. This points to a cause and effect relation. In eyes with primary open angle glaucoma a significant correlation between the amount of plaque material in the subendothelial region of Schlemms Canal and loss of axons in the optic nerve was also found. The correlation with IOP however was not present. Here it is suggested that the plaque formation does not cause an increase of IOP by itself. So both plaques and nerve fiber loss are caused by common factors. The author further comments on the mutation in the MYOC gene. One of the factors increased in the aqueous humor of nearly 50% of eyes with POAG is TGF-beta2. In vitro TGF-beta2 can induce expression of the stress protein alfaB-crystallin and the MYOC/TIGR protein. It can also stimulate formation of extracellular matrix components like fibronectin and of the enzyme tissue transglutaminase which crosslinks fibronectin to complexes not degradable by metalloproteinases.
Department of Anatomy, University Erlangen-Nurnberg
Classification:
1.3 Pathogenesis (Part of: 1 General aspects)
2.5 Meshwork (Part of: 2 Anatomical structures in glaucoma)