Localization of TGF-beta type II receptor and ED-A fibronectin in normal conjunctiva and failed filtering blebs.
OBJECTIVE
The cytokine transforming growth factor-beta (TGF-beta), and the ED-A splice variant of the extracellular matrix protein fibronectin modulate wound healing and scar formation. To further elucidate their possible role in filtering bleb scarring after glaucoma surgery in human eyes in vivo, we studied the cell type specific localization of TGF-beta receptors and the presence of ED-A fibronectin in sections of normal conjunctiva and scarred filtering blebs.


METHODS
Cryosections of normal conjunctiva (four patients) and scarred filtering blebs (seven patients) were studied by double-label immunofluorescence. Antibodies against PECAM-1 and prolyl-4-hydroxylase allowed for specification of vascular endothelial cells and activated fibroblasts, respectively. TGF-beta receptor type II (TGF-beta-RII), alpha-smooth muscle actin, O-linked sialoglycoprotein, fibronectin and the ED-A fibronectin splice-variant were also detected using specific antibodies. Labeled sections were viewed with a confocal laser scanning microscope.


RESULTS
Vascular endothelial cells expressed TGF-beta-RII in both normal and scarred tissue. TGF-beta-RII was sparsely detected in the fibroblasts of normal conjunctiva while it was strongly expressed in most fibroblasts of the scarred filtering blebs. Similarly, ED-A fibronectin was not detected in the extracellular matrix of normal conjunctiva but abundantly present in scarred filtering blebs.


CONCLUSIONS
Filtering bleb scarring is associated with an abundant expression of TGF-beta receptors in activated fibroblasts and the deposition of the fibrogenic ED-A fibronectin splice-variant. These data support the concept of targeting TGF-beta signaling to prevent scar formation after filtering glaucoma surgery.
Meyer-Ter-Vehn
Tobias
T
Department of Ophthalmology, University of Würzburg, Würzburg, Germany. meyer_T3@augenklinik.uni-wuerzburg.de
Grehn
Franz
F
Schlunck
Günther
G
D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D017398:Alternative Splicing / Q000235:genetics; D015415:Biomarkers / Q000378:metabolism; D001768:Blister / Q000378:metabolism* / Q000473:pathology*; D002452:Cell Count; D002648:Child; D003228:Conjunctiva / Q000378:metabolism* / Q000473:pathology*; D004727:Endothelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*
D000199:Actins; D015415:Biomarkers; D005353:Fibronectins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D018125:Receptors, Transforming Growth Factor beta; D011393:Procollagen-Proline Dioxygenase; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II