Changes in Corneal Basal Epithelial Phenotypes in an Altered Basement Membrane

To examine the corneal epithelial phenotype in an altered basement membrane.Corneas from 9 patients with symptoms of continuous unstable corneal curvature (CUCC) were harvested by penetrating keratoplasty and subjected to histology examination and immunohistochemical staining with transactivating and N-terminally truncated pP63 transcript (ΔNp63), cytokeratin 3 (Krt3), ATP-binding cassette sub-family G member 2 (ABCG2), connexin 43 (CX43), p38 mitogen-activated protein kinases (p38MAPK), activating protein 2 (TFAP2), and extracellular signal-regulated kinase (Erk1/2) monoclonal antibodies. Positive immunostaining with ABCG2, p38MAPK, and TFAP2 monoclonal antibodies was observed in the basal epithelial cells of CUCC patients, and CX43 and ΔNp63 were detected in the full-thickness epithelial cells of CUCC patients.Our results indicate that alteration of the corneal basement membrane induces a de-differentiation-like phenotype in corneal basal epithelial cells

An RK cornea (case 8) immunostained with ABCG2, p38MAPK, Erk1/2, and TFAP2 antibodies (200×).

<p>In the limbus of normal cornea, ABCG2 was observed in the basal epithelial cell layers (C). However, the corneal epithelial cells of the central cornea were not stained by ABCG2 antibody (B). In the RK-wounded area of CUCC cornea, ABCG2 staining was obvious in the basal epithelial cell layers (A). Furthermore, p38MAPK (D) and <b>TFAP2</b> (J) were also observed in the basal epithelial cells of the wounded area of the RK. The central part of the normal cornea and limbus did not demonstrate expression of P38MAPK (E, F) or <b>TFAP2</b> (K, L). <b>Erk1/2</b> was not identified in the basal epithelial cells of any of these samples (G, H, I). Moreover, an intact Bowman's membrane was found only in the central part of normal cornea. However, a disrupted Bowman's membrane was found in both the CUCC cornea and the normal limbus. The negative controls are also shown (M, N, O, 100×).</p

Clinical manifestations of seven patients with continuously unstable curvatures of corneas (CUCCs) for keratoplasty.

<p>PKP = penetrating keratoplasty; DALK = deep anterior lamellar keratoplasty.</p

Double immunofluorescent staining of connexin 43 (CX43) and ΔNp63 in a normal central cornea (A), limbus (B) and a CUCC cornea (C) (200×).

<p>The epithelial cells of a normal central cornea and the suprabasal epithelial cells of the limbus were positively stained by CX43 antibody (green color); only limbal basal epithelial cells were positively stained by ΔNp63 antibody (orange color and arrows). Both CX43 and ΔNp63 were detected throughout the epithelial cells of CUCC corneas.</p

Immunohistochemical patterns between the normal cornea and the RK case with the markers of corneal epithelial stem/progenitor cells and corneal-type epithelial differentiation.

<p>Immunohistochemical patterns between the normal cornea and the RK case with the markers of corneal epithelial stem/progenitor cells and corneal-type epithelial differentiation.</p

Comparison of immunohistochemical patterns between normal cornea and 8 cases of CUCCs with the markers of corneal epithelial stem/progenitor cells and corneal-type epithelial differentiation.

<p>Comparison of immunohistochemical patterns between normal cornea and 8 cases of CUCCs with the markers of corneal epithelial stem/progenitor cells and corneal-type epithelial differentiation.</p