Connective tissue growth factor in pterygium: simultaneous presence with vascular endothelial growth factor – possible contributing factor to conjunctival scarring

Abstract

Background. Various growth factors have been detected in pterygium and been associated with its vasculogenesis. The basic pathophysiological mechanisms responsible especially for the fibrotic activity in pterygium are, however, not yet known. Connective tissue growth factor (CTGF) has been shown to be substantially involved in various processes of fibrosis. We report on the presence of CTGF in pterygium and its simultaneous presence with vascular endothelial growth factor (VEGF).

Methods. Samples of pterygium were collected during surgery with informed consent of the patients. Specific, non-commercial primary antibodies against CTGF were used to detect CTGF using immunohistochemistry. Specificity of antibodies was confirmed with Western-blot analysis. The same specimens were stained with commercial antibodies for VEGF. Additionally RT-PCR analysis was performed from pterygium samples.

Results. CTGF was detected in the epithelium of all samples as well as in some stromal keratocytes. The RT-PCR confirmed the identity of CTGF in these samples. The staining pattern differed slightly from that of VEGF, which was detected in all samples. The control sections were negative.

Conclusion. CTGF is present in the epithelium of a majority of pterygia and probably contributes to fibrosis. Simultaneous presence with VEGF suggests growth factor interaction and possible involvement in apoptotic dysregulation.