P 137Latent TGF- ß 1 binding protein (LTBP-1): A new marker for intra- und extraocular pseudoexfoliation deposits
U. Schlötzer-Schrehardt, M. Küchle, C. Hofmann-Rummelt,
Background: Pseudoexfoliation (PEX) syndrome is a generalized process of the extracellular matrix characterized by the accumulation of an abnormal pathognomonic material in various intra- and extraocular tissues. Whereas the intraocular manifestations can be directly diagnosed by biomicroscopic observations, the extraocular manifestations can presently only be diagnosed by electron microscopy. In order to better evaluate the distribution and precise localization of PEX deposits in the various organ systems, we searched for a relatively specific immunohistochemical marker for PEX material on the light microscopic level.
Methods: Eyes and tissue specimens of various organ systems obtained from 4 organ donors with ocular PEX syndrome and age-matched control tissues were investigated by electron microscopy and immunohisto-chemistry using antibodies against elastic microfibrillar components.
Results: Out of a panel of antibodies tested, the immunolabeling of both intra- and extraocular PEX deposits with antibodies against latent TGF- ß 1 binding protein (LTBP-1) was particularly prominent. In addition to the known intraocular sites of PEX material accumulations, focal plaque-like LTBP-1 positive deposits could be observed in the conjunctival stroma, optic nerve meninges, skin, heart muscle, lungs and kidney from donors with PEX syndrome, but not in the control tissues. Electron microscopy confirmed the presence of typical fibrillar PEX material in the respective tissues.
Discussion: Antibodies against LTBP-1 provide a new and relatively specific marker for PEX deposits in intra- and extraocular locations. Systematic screening of PEX accumulations in a larger number of tissue specimens may help to elucidate the functional implications and consequences of the systemic manifestations in PEX patients.
Department of Ophthalmology, University Erlangen-Nürnberg, Schwabachanlage 6, D-91054 Erlangen