Expression of Angiogenesis-Related Factors in Human Corneas after Cultivated Oral Mucosal Epithelial Transplantation

Abstract

We analyzed the expression of angiogenesis-related factors in corneal tissues that had undergone previously autologous cultivated oral mucosal epithelial transplantation (COMET). Six eyes from four chemically- and two thermally-injured patients with limbal stem cell deficiency who received COMET to promote wound healing were studied retrospectively. Immunoconfocal microscopy was performed on corneal specimens from the patients after COMET, as well on normal corneas, conjunctiva, and oral mucosa for keratin 8, fibroblast growth factor-2 (FGF-2), VEGF, collagen XVIII (endostatin), pigment epithelium-derived factor (PEDF), soluble fms-like tyrosine kinase-1 (sFlt-1), tissue inhibitor of metalloproteinase-3 (TIMP-3), thrombospondin-1 (TSP-1), and interleukin-1 receptor antagonist (IL-1ra). FGF-2, VEGF, endostatin, PEDF, and IL-1ra were detected in all the samples, with signals for FGF-2, VEGF, and IL-1ra localized to the full-thickness epithelial layer, as signals for endostatin limited to the basement membrane. Expression of PEDF varied in tissues, with a preferential expression in the suprabasal epithelial layer. FGF-2 and IL-1ra were abundantly expressed in the basal epithelial layer in specimens with increased stratification. Signals for sFlt-1, TIMP-3, and TSP-1 were detected in normal corneal epithelium, and in a specimen containing corneal epithelium, but were negative in all other specimens. Expression of FGF-2, VEGF, PEDF, endostatin, and IL-1ra was similar in normal corneas, conjunctiva, oral mucosa, and corneas after COMET. Expression of sFlt-1, TIMP-3, and TSP-1 was limited to normal corneas and negative for other tissues. A lack of the aforementioned antiangiogenic factors may contribute to the peripheral corneal neovascularization seen after COMET.