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


CONCLUSIONS
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.
van Setten
Gysbert
G
St. Eriks Eye Clinic, Karolinska Institutet, Polhemsgatan 50, 11282 Stockholm, Sweden, g.van.setten@sankterik.se
Aspiotis
Miltos
M
Blalock
Timothy D
TD
Grotendorst
Gary
G
Schultz
Gregory
G
D015153:Blotting, Western; D002921:Cicatrix / Q000378:metabolism; D003229:Conjunctival Diseases / Q000378:metabolism*; D055513:Connective Tissue Growth Factor; D016228:Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008222:Lymphokines / Q000235:genetics / Q000378:metabolism*; D011625:Pterygium / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
C526317:CCN2 protein, human; D016228:Endothelial Growth Factors; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D055513:Connective Tissue Growth Factor