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Localization of TGF-beta type II receptor and ED-A fibronectin in normal conjunctiva and failed filtering blebs.

Meyer-Ter-Vehn T, Grehn F, Schlunck G - Mol. Vis. (2008)

Bottom Line: 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.Vascular endothelial cells expressed TGF-beta-RII in both normal and scarred tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Würzburg, Würzburg, Germany. meyer_T3@augenklinik.uni-wuerzburg.de

ABSTRACT

Purpose: 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.

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Localization of α-smooth muscle actin (SMA) and the absence of lymphatic endothelium in scarred filtering bleb tissue. Serial sections were double labeled for TGF-β-RII (A, D, and G; green) and α-SMA (B, C), O-linked sialoglycoprotein (E, F), and PECAM-1 (H, I, red). α-SMA is colocalized to TGF-β-RII in stromal fibroblasts and perivascular cells (A,B,C). Vascular structures expressing TGF-β-RII(H) were negative for markers of lymphatic endothelium (E).Some collagen fiber autofluorescence is present in the red channel (B, E, H), Scale bar represents 50 µm.
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f4: Localization of α-smooth muscle actin (SMA) and the absence of lymphatic endothelium in scarred filtering bleb tissue. Serial sections were double labeled for TGF-β-RII (A, D, and G; green) and α-SMA (B, C), O-linked sialoglycoprotein (E, F), and PECAM-1 (H, I, red). α-SMA is colocalized to TGF-β-RII in stromal fibroblasts and perivascular cells (A,B,C). Vascular structures expressing TGF-β-RII(H) were negative for markers of lymphatic endothelium (E).Some collagen fiber autofluorescence is present in the red channel (B, E, H), Scale bar represents 50 µm.

Mentions: Specimens of scarred filtering blebs were rich in vascular structures as detected by PECAM-1 staining (Figure 2B,C). PECAM-1 positive cells stained for TGF-β-RII (Figure 2B,C), but non-vascular spindle-shaped cells were also expressing this receptor (Figure 2C, arrows). The latter appear to be activated fibroblasts as detected by an anti-prolyl-4-hydroxylase antibody (Figure 3B,C). These cells were abundant in scarred filtering blebs, and most of them expressed TGF-β-RII (Figure 3B,C, arrows). In scarred filtering blebs, fibroblasts also expressed α-SMA (Figure 4B,C), which was detected in perivascular cells as well. Lymphatic endothelium was not detected (Figure 4E,F).


Localization of TGF-beta type II receptor and ED-A fibronectin in normal conjunctiva and failed filtering blebs.

Meyer-Ter-Vehn T, Grehn F, Schlunck G - Mol. Vis. (2008)

Localization of α-smooth muscle actin (SMA) and the absence of lymphatic endothelium in scarred filtering bleb tissue. Serial sections were double labeled for TGF-β-RII (A, D, and G; green) and α-SMA (B, C), O-linked sialoglycoprotein (E, F), and PECAM-1 (H, I, red). α-SMA is colocalized to TGF-β-RII in stromal fibroblasts and perivascular cells (A,B,C). Vascular structures expressing TGF-β-RII(H) were negative for markers of lymphatic endothelium (E).Some collagen fiber autofluorescence is present in the red channel (B, E, H), Scale bar represents 50 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2255025&req=5

f4: Localization of α-smooth muscle actin (SMA) and the absence of lymphatic endothelium in scarred filtering bleb tissue. Serial sections were double labeled for TGF-β-RII (A, D, and G; green) and α-SMA (B, C), O-linked sialoglycoprotein (E, F), and PECAM-1 (H, I, red). α-SMA is colocalized to TGF-β-RII in stromal fibroblasts and perivascular cells (A,B,C). Vascular structures expressing TGF-β-RII(H) were negative for markers of lymphatic endothelium (E).Some collagen fiber autofluorescence is present in the red channel (B, E, H), Scale bar represents 50 µm.
Mentions: Specimens of scarred filtering blebs were rich in vascular structures as detected by PECAM-1 staining (Figure 2B,C). PECAM-1 positive cells stained for TGF-β-RII (Figure 2B,C), but non-vascular spindle-shaped cells were also expressing this receptor (Figure 2C, arrows). The latter appear to be activated fibroblasts as detected by an anti-prolyl-4-hydroxylase antibody (Figure 3B,C). These cells were abundant in scarred filtering blebs, and most of them expressed TGF-β-RII (Figure 3B,C, arrows). In scarred filtering blebs, fibroblasts also expressed α-SMA (Figure 4B,C), which was detected in perivascular cells as well. Lymphatic endothelium was not detected (Figure 4E,F).

Bottom Line: 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.Vascular endothelial cells expressed TGF-beta-RII in both normal and scarred tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Würzburg, Würzburg, Germany. meyer_T3@augenklinik.uni-wuerzburg.de

ABSTRACT

Purpose: 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.

Show MeSH
Related in: MedlinePlus