Electrophilic PPAR[gamma] ligands inhibit corneal fibroblast to myofibroblast differentiation in vitro: A potentially novel therapy for corneal scarring

A critical component of corneal scarring is the TGF[beta]-induced differentiation of corneal keratocytes into myofibroblasts. Inhibitors of this differentiation are potentially therapeutic for corneal scarring. In this study, we tested the relative effectiveness and mechanisms of action of two electrophilic peroxisome proliferator-activated receptor gamma (PPAR[gamma]) ligands: cyano-3,12-dioxolean-1,9-dien-28-oic acid-methyl ester (CDDO-Me) and 15-deoxy-[DELTA].sup.-12,14-prostaglandin J.sub.2 (15d-PGJ.sub.2) for inhibiting TGF[beta]-induced myofibroblast differentiation in vitro. TGF[beta] was used to induce myofibroblast differentiation in cultured, primary human corneal fibroblasts. CDDO-Me and 15d-PGJ.sub.2 were added to cultures to test their ability to inhibit this process. Myofibroblast differentiation was assessed by measuring the expression of myofibroblast-specific proteins ([alpha]SMA, collagen I, and fibronectin) and mRNA ([alpha]SMA and collagen III). The role of PPAR[gamma] in the inhibition of myofibroblast differentiation by these agents was tested in genetically and pharmacologically manipulated cells. Finally, we assayed the importance of electrophilicity in the actions of these agents on TGF[beta]-induced [alpha]SMA expression via Western blotting and immunofluorescence. Both electrophilic PPAR[gamma] ligands (CDDO-Me and 15d-PGJ.sub.2) potently inhibited TGF[beta]-induced myofibroblast differentiation, but PPAR[gamma] was only partially required for inhibition of myofibroblast differentiation by either agent. Electrophilic PPAR[gamma] ligands were able to inhibit myofibroblast differentiation more potently than non-electrophilic PPAR[gamma] ligands, suggesting an important role of electrophilicity in this process. CDDO-Me and 15d-PGJ.sub.2 are strong inhibitors of TGF[beta]-induced corneal fibroblast to myofibroblast differentiation in vitro, suggesting this class of agents as potential novel therapies for corneal scarring warranting further study in pre-clinical animal models.Academi

Evaluation of Optic Disc Edema in Long-Duration Spaceflight Crewmembers using retinal Photography

Background: Long-duration spaceflight crewmembers are at risk for spaceflight-associated neuro-ocular syndrome (SANS). One of the earliest manifestations of SANS is optic disc edema (ODE), which could be missed using the subjective Frisén scale. The primary objective of this study is to determine the inter-rater and intrarater reliability of Frisén grade for SANS-induced ODE among a trained observer cohort. The secondary objective is to propose a standardized evaluation process for SANS-induced ODE across International Space Station Partner Agencies. Methods: Retrospective, double-blinded diagnostic study. Preflight and postflight fundus photographs were presented to subject matter experts who identified and graded ODE. Pairs of images were also compared side-by-side for disc ranking. Grader concordance was assessed for Frisén grading and disc ranking. Results: Expert graders identified Grade 1 ODE in 17.35% of images from 62 crewmembers (9 female, mean [SD] age, 47.81 [5.19] years). Grades 2 and 3 were identified less than 2% of the time. Concordance in Frisén grades among pairs of graders was 70.99%. Graders identified a difference in preflight and postflight fundus photographs 17.21% of the time when using disc ranking. Pairs of graders had complete concordance in disc ranking 79.79% of the time. Perfect intrarater agreement between Frisén grade and disc ranking occurred 77.7% of the time. Conclusions: These findings demonstrate intergrader and intragrader variability when using the Frisén scale to identify SANS-induced ODE, which is typically milder in presentation than terrestrial cases of idiopathic intracranial hypertension. It is possible to miss early ODE on fundoscopy alone, making it insufficient as a sole criterion for the diagnosis of SANS. A more sensitive and objective method of surveillance is necessary to monitor international crewmembers for ODE, perhaps using a multimodal approach that includes technology such as optical coherence tomography

Electrophilic PPARγ ligands inhibit corneal fibroblast to myofibroblast differentiation in vitro: A potentially novel therapy for corneal scarring

A critical component of corneal scarring is the TGFβ-induced differentiation of corneal keratocytes into myofibroblasts. Inhibitors of this differentiation are potentially therapeutic for corneal scarring. In this study, we tested the relative effectiveness and mechanisms of action of two electrophilic peroxisome proliferator-activated receptor gamma (PPARγ) ligands: cyano-3,12-dioxolean-1,9-dien-28-oic acid-metheyl ester (CDDO-Me) and 15-deoxy-Δ-12,14-prostaglandin J(2) (15d-PGJ(2)) for inhibiting TGFβ-induced myofibroblast differentiation in vitro. TGFβ was used to induce myofibroblast differentiation in cultured, primary human corneal fibroblasts. CDDO-Me and 15d-PGJ(2) were added to cultures to test their ability to inhibit this process. Myofibroblast differentiation was assessed by measuring the expression of myofibroblast-specific proteins (αSMA, collagen I, and fibronectin) and mRNA (αSMA and collagen III). The role of PPARγ in the inhibition of myofibroblast differentiation by these agents was tested in genetically and pharmacologically manipulated cells. Finally, we assayed the importance of electrophilicity in the actions of these agents on TGFβ-induced αSMA expression via Western blotting and immunofluorescence. Both electrophilic PPARγ ligands (CDDO-Me and 15d-PGJ(2)) potently inhibited TGFβ-induced myofibroblast differentiation, but PPARγ was only partially required for inhibition of myofibroblast differentiation by either agent. Electrophilic PPARγ ligands were able to inhibit myofibroblast differentiation more potently than non-electrophilic PPARγ ligands, suggesting an important role of electrophilicity in this process. CDDO-Me and 15d-PGJ(2) are strong inhibitors of TGFβ-induced corneal fibroblast to myofibroblast differentiation in vitro, suggesting this class of agents as potential novel therapies for corneal scarring warranting further study in pre-clinical animal models