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A comparative immunohistochemical study of human corneotrabecular tissue
B Foets1, J van den Oord, K Engelmann
1Department of Ophthalmology, UZ Sint-Rafaël, Leuven, Belgium.
Insights
Human corneal endothelial cells (HCECs) show neuroectodermal markers, suggesting a neural origin. Cells in Schlemm's canal resemble vascular endothelium, not HCECs.
Area of Science:
- Ophthalmology
- Cell Biology
- Neuroscience
Background:
- The cellular origins and phenotypes of ocular tissues are crucial for understanding eye development and disease.
- Human corneal endothelial cells (HCECs) play a vital role in maintaining corneal clarity.
Purpose of the Study:
- To comparatively analyze the immunophenotypes of HCECs, keratocytes, trabecular cells, and cells lining the canal of Schlemm.
- To investigate the potential neuroectodermal origin of HCECs.
Main Methods:
- In situ immunohistochemical techniques using a wide array of antibodies.
- Antibodies targeted intermediate filament proteins, vascular endothelial markers, neuroectodermal/neuroendocrine markers, and specific monoclonal antibodies against HCECs.
Main Results:
- HCECs coexpressed cytokeratins and neurofilaments, staining positive for neuron-specific enolase (NSE) and expressing neural cell adhesion molecules (N-CAM).
- Trabecular cells also expressed NSE and N-CAM.
- Cells lining the canal of Schlemm exhibited immunophenotypical features similar to vascular endothelial cells, distinct from HCECs.
Conclusions:
- The findings support a neuroectodermal origin for HCECs.
- Cells of the canal of Schlemm share characteristics with vascular endothelium, differentiating them from corneal endothelial cells.
Abstract:
Using in situ immunohistochemical techniques and a broad panel of antibodies directed against intermediate filament proteins, vascular endothelial markers, neuroectodermal/neuroendocrine markers, and monoclonal antibodies raised against human corneal endothelial cells (HCECs), a comparative phenotypical analysis was performed on HCECs, keratocytes, trabecular cells, and cells lining the canal of Schlemm. The coexpression of cytokeratins and neurofilaments by HCECs argues in favor of a neuroectodermal origin, which is further supported by the fact that they stain positive for neuron-specific enolase (NSE) and that they express neural cell adhesion molecules (N-CAM) at their surface. The expression of NSE and N-CAM also applies to the trabecular cells. The cells lining the canal of Schlemm were found to share many immunophenotypical features with vascular endothelial cells (i.e., factor-VIII-related antigen and BMA-120), rather than with HCECs. This was further supported by the reactivity of two monoclonal antibodies (i.e., 9.3 E and 5.52 H) that were raised against HCECs, and which labelled vascular endothelium and cells lining Schlemm's canal.