Severe Abnormalities of Lens Epithelial Cells in Exfoliation Syndrome: A Transmission Electron Microscopy Study of Patients with Age-Related Cataract.

Affiliation

Laboratory of Histology and Embryology, Medical School, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece. [Email]

Abstract

Background andobjectives: The aim of this study was to examine via electron microscopy the lens epithelial cells in age-related cataracts and compare the findings between patients with and without exfoliation syndrome, in the Greek population. Materials and Methods: Twenty-one patients with age-related cataracts, older than 60 years, were included in the study. Eleven of them also suffered from exfoliation syndrome. Anterior lens capsules, obtained during phacoemulsification, were examined with a transmission electron microscope. Results: In all cases, ultrastructural features of diffuse intracellular and extracellular oedema were noticed to a varying degree and transparent vacuoles were detected. Often, there was more than one layer of cells, giving the impression that healthier cells tried to cover neighboring cells presenting extensive damage. Commonly, cells lost their regular shape and appeared with expanded nuclei carrying dense granules. Apoptotic cells were also detected. The epithelial cells frequently were completely destroyed or absent, exhibiting loose connections amongst them or with the basement membrane. In exfoliation syndrome (XFS) patients the alterations were more severe. Additionally, the lens epithelial cells (LECs) apical cell membrane appeared with varying distances from the basement membrane, due to different cell "heights", creating an irregular margin of the epithelium (p<0.05). Conclusion: Transmission electron microscope (TEM) examination revealed ultrastructural abnormalities in all patients' lens epithelia, more extended and more frequently observed in XFS group. In all cases, the lesions were comparable to those described in severe pathologies, all of which were excluded from the study. Environmental factors such as increased ultraviolet B (UVB) radiation exposure in Mediterranean countries, genetic factors, epigenetic factors, or all of them, could contribute to these alterations. Further epidemiological and molecular biology research is needed, so as to justify these results.

Keywords

age-related cataract,anterior lens capsule,electron microscopy,exfoliation syndrome,lens epithelial cells,senile cataract,

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