Optical Effects of Anti-TGFβ Treatment after Photorefractive Keratectomy in a Cat Model

Abstract

Purpose To assess the contribution of corneal myofibroblasts to optical changes induced by photorefractive keratectomy (PRK) in a cat model. Methods First, we tested the transforming growth factor β (TGFβ)-dependence of feline corneal keratocyte differentiation into α-smooth muscle actin (αSMA)-positive myofibroblasts in vitro. Twenty-nine eyes from 16 cats were then treated with −10D PRK in vivo and divided into two post-operative treatment groups: (1) eyes that received 100μg anti-TGFβ antibody for 7 days, followed by 50μg Dexamethasone for another 7 days to inhibit myofibroblast differentiation; (2) eyes that received vehicle solution for 14 days (controls). Corneal thickness and reflectivity were measured by optical coherence tomography. Wavefront sensing was performed in the awake-behaving state pre-operatively and 2, 4, 8 and 12 weeks post-operatively. Wound healing was monitored using in vivo confocal imaging and postmortem αSMA immunohistochemistry. Results In culture, TGFβ caused cat corneal keratocytes to differentiate into αSMA-positive myofibroblasts, an effect that was blocked by co-incubation with anti-TGFβ antibody. In vivo, anti-TGFβ treatment post-PRK resulted in less αSMA immunoreactivity in the sub-ablation stroma, lower corneal reflectivity, less stromal re-growth and lower non-spherical, higher order aberration (HOA) induction than controls. However, there were no inter-group differences in epithelial regeneration or lower order aberration changes. Conclusions Anti-TGFβ treatment reduced feline myofibroblast differentiation in vitro and following PRK. It also decreased corneal haze and fine-grained irregularities in ocular wavefront after PRK, suggesting that attenuation of the differentiation of keratocytes into myofibroblasts can significantly enhance optical quality after refractive surface ablations.

Reversal of fibrosis by TGF-β3 in a 3D in vitro model

“…Although multiple studies have demonstrated that scarring can be blunted by inhibiting the fibrosis pathway at the time of wounding (Blalock et al 2012; Buhren et al 2009; Huxlin et al 2013; Jester et al 1997; Sriram et al 2013; Talamo et al 1991), the current studies, to the best of our knowledge, are the first to demonstrate that an established model of human fibrosis can be reversed. Our previous studies on TGF-β3 (Karamichos et al 2011) have shown the prevention of scarring in vitro; however, in the present study, we attempted to reverse an established scar-like ECM.…”

The Aryl Hydrocarbon Receptor Ligand ITE Inhibits TGFβ1-Induced Human Myofibroblast Differentiation

“…According to the results, blocking TGF␤ signaling after PRK reduced corneal haze 51,52 and enhanced optical quality. 53 Although the efficacy of anti-TGF␤ therapy has been demonstrated in animals and related pharmaceutical approaches to the treatment of IPF are close to clinical trial, 54 an ideal antifibrotic therapeutic candidate has yet to be identified. In this study, ITE has proven to be a very effective inhibitor of TGF␤1 signaling in vitro.…”

Wounding the cornea to learn how it heals

“…Additional research has focused on cat corneal endothelial cells (Huang et al, 1989; Petroll et al, 1999; Rotatori et al, 1994). Corneal scarring in response to corneal epithelial wound healing is also being studied in cats (Buhren et al, 2009; Huxlin et al, 2013). Cats, like rabbits, respond similarly to humans in terms of corneal scarring (Nagy et al, 2007).…”