Abstract
Purpose::
To evaluate the immunohistochemical profile of keratocytes and endothelium in corneal tissue of posterior polymorphous corneal dystrophy (PPCD) and normal controls.
Methods::
Formalin-fixed, paraffin-embedded sections of four corneas with the diagnosis of PPCD, and three corneas with no history of corneal disease were stained with monocloncal antibodies that react with vimentin, FB5, fibroblast growth factor -2 (FGF-2) , transforming growth factor beta-2 (TGF- B2), transforming growth factor-beta receptor (TGF-BR), and smooth muscle actin (SMA). Degree and location of immunoreactivity was assessed by light microscopy.
Results::
Keratocytes in all corneas stained uniformly positive with vimentin, TGF-B2, and TGF-BR. Keratocytes stained with FB5 in 2/4 corneas with PPCD, and in 3/3 control corneas. FGF-2 stained occasional keratocyte nuclei in 2/4 PPCD corneas and in 3/3/ corneal corneas. There was focal staining of keratocyte nuclei with SMA in 3/4 PPCD corneas, and in 0/3 controls. Corneal endothelium stained strongly with FGF-2 and TGF-B2 in all corneas; with vimentin in 3/4 PPCD corneas, and 3/3 controls; with FB5 in 3/4 PPCD corneas, and in 3/3 controls; and TGF-BR in 3/4 PPCD corneas and in 3/3 controls. Endothelial cells stained strongly positive with SMA in 3/4 PPCD corneas, especially in areas of endothelial multi-layering, and in no control corneas. SMA-positive stromal fibroblasts were noted in proximity to SMA-positive endothelium in some cases.
Conclusions::
No significant deviations were noted in immunostaining of PPCD versus controls with FB5, vimentin, FGF-2, TGF-B, and TGF-B2. However, strong staining of corneal endothelium with SMA was noted in 3/4 PPCD corneas, especially in areas of endothelial multi-layering; this was not present in control cornea endothelium. Myofibroblastic metaplasia of endothelium may explain the ability of corneal endothelium to form multiple layers, and to overgrow trabecular meshwork in PPCD.
Keywords: pathology: human • cornea: endothelium • cornea: stroma and keratocytes