Mechanism of Scarring After Glaucoma Surgery Identified
(HealthDay News) – Vascular endothelial growth factor (VEGF) triggers the formation of myofibroblasts associated with scarring after glaucoma surgery through a particular signaling pathway, according to a study published online May 17 in The American Journal of Pathology.
Noting that previous studies have shown that inhibiting VEGF reduces subconjunctival fibrosis and improves outcomes after glaucoma surgery, Hae-Young L. Park, MD, from The Catholic University of Korea in Seoul, and colleagues used a rabbit trabeculectomy model to examine the effects of VEGF stimulation and inhibition (via the inhibitor bevacizumab) on myofibroblast transformation.
The researchers found that VEGF stimulation induced transforming growth factor (TGF)-β1 expression, down-regulated epithelial markers (E-cadherin and β-catenin), and up-regulated the mesenchymal marker α-smooth muscle actin in the subconjunctival layers after trabeculectomy. The conjunctival and subconjunctival layers at the site of trabeculectomy showed increased expression of the important myofibroblast transformation factors Smad and Snail. VEGF stimulation activated myofibroblast transformation while VEGF inhibition reduced myofibroblast transformation.
"These findings suggest that VEGF potentially affected the TGF- β1/Smad/Snail pathway, thereby triggering myofibroblast transformation," Park and colleagues conclude. "This gives an experimental basis for the use of anti-VEGF agents in glaucoma surgery."