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Published on: July 6, 2015
Absence of scar formation in human donor cornea with prior laser in situ keratomileusis
Siegfried G Priglinger1, Christian-Albrecht May, Claudia S Alge
1Department of Ophthalmology, Ludwig Maximilians University, Munich, Germany.
Purpose:
To investigate transglutaminases (enzymes capable of cross-linking extracellular matrix proteins to proteolysis-resistant complexes during scar tissue formation) in a human donor cornea after successful laser in situ keratomileusis (LASIK) without clinical complications and to compare with the results in a human donor cornea with corneal scarring after corneal injury.
Setting:
Department of Ophthalmology, Ludwig-Maximilians University, Munich, Germany.
Methods:
A donor cornea with prior uneventful LASIK treatment and 1 with corneal scarring after penetrating injury were investigated. Cryostat sections were stained immunohistochemically for tissue transglutaminase (tTG), keratocyte transglutaminase (kTG), and their reaction product epsilon-(gamma-glutamyl)-lysine.
Results:
With light microscopy, the flap interface of the LASIK-treated eye could hardly be detected, while in the injured eye, infiltration of cells and a clear margin next to the scar formation were present. Immunohistochemistry demonstrated a distinct staining for tTG, kTG, and epsilon-(gamma-glutamyl)-lysine in the corneal scar. In contrast, neither transglutaminase nor epsilon-(gamma-glutamyl)-lysine staining could be observed at the flap margin or in the interface of the LASIK-treated donor eye.
Conclusions:
Irreversible protein cross-linking of transglutaminases via epsilon-(gamma-glutamyl)-lysine connections seem to be indicators for scarring in corneal wound healing. The absence of transglutaminases and their reaction product epsilon-(gamma-glutamyl)-lysine in a LASIK-treated cornea supports the idea of missing scar tissue formation after LASIK surgery.
