Abstract
Purpose: :
Neprilisin (NEP, CD-10, CALLA, neutral endopeptidase 24.11, enkephalinase) is a metallopeptidase expressed in some epithelial and stromal normal cells of many organs. Is involved in the metabolism of a number of regulatory peptides and peptide signalling at the cell surface. Probably has specific roles in the control of growth and differentiation of some epithelial and stromal systems, but its expression has not been described in the normal cornea. The aim of our study was to know if stromal keratocytes in both, degenerative and reactive pathology, would express CD10 as a marker of functional activation.
Methods: :
immunohistochemical staining for CD10, CD34, c1a, muscle specific actin and CD 68 were preformed in 5 postmortem normal corneas, and 5 cases each of a) keratoconus b) lattice corneal dystrophy c) transplant rejection d) keratitis e) bullous keratopathy. Also three cases of keratoconus post excimer laser were included. In all of them, an informed consent was signed by the patient or relatives according to Spanish LIB 14/2007.
Results: :
The keratocytes in normal cornea did not expressed CD 10 marker, while its expression, grading from weack to intense, was observed in 2 of 5 lattice corneal dystrophy; 5 of 5 of both transplant rejection and keratitis; 3 of 5 bullous keratopathy and 1 of 5 keratoconus. Its expression parallels to CD34 expression, but only in some cases is associated to Cd68 and actin, suggesting CD10 specific function not directly associated to myofibroblastic or macrophagic transformation of keratocytes. Very weak and isolated expression was found in post lasik cases.
Conclusions: :
Reactive corneal keratocytes were consistently positive for CD10 in transplant rejection and keratitis, but weaker in corneal degeneration, probably as reflection of its role in an early response to the "noxa". Its role is not parallels to myofibrobastic transformation. The CD10 function as neutral endopeptidase involved in the metabolism of regulatory peptides, would suggest a specialized contribution to the concentration of peptide signalling molecules or additional mechanism of cell-to cell interaction.
Keywords: cornea: stroma and keratocytes • inflammation • pathology: experimental